MCB4203 Exam 2

V. cholerae (Cholera), Salmonella enterica serovar Typhi (typhoid fever), Mycobacterium tuberculosis (tuberculosis) --> can be asymptomatic in some individuals.

"overt pathogens"

E. coli and Shigella as close "cousins"; relevance of virulence plasmid in Shigella, loss of other genes from E. coli?

- DNA-DNA reassociation kinetics - DNA exchange & recombination (transduction & conjugation) - co-linearity of genomes - multi-locus enzyme polymorphisms - whole-genome sequence comparisons

main species/strains of Shigella; where are they found?

- S. dysenteriae: epidemic; produces Shiga toxin; most severe disease. - S. flexneri: developing countries. - S. boydii: not very common. - S. sonnei: developed countries.

neutralization or resistance to phagolysosomal components?

- acquire traits that reduce effectivity of toxic compounds released into phagolysosome after fusion (bacterial cell membranes w/ altered structures, modified LPS, capsules) - acid-tolerance; can survive for periods of time within the acidic phagolysosomal compartments.

major mechanisms of antibiotic resistance?

- directly targeting antibiotic - targeting antibiotic availability - target modification

function of IpaB?

- forms translocon pore in mammalian membrane w/ IpaC - IpaB/IpaC mediate uptake of coated beads

host contribution factors to virulence?

- function of host immune systems - evasion of host pathways by pathogens (molecular mimicry, subversion of host defenses "hiding") - identification of novel antimicrobials (host- & pathogen-targeting drugs)

genetic approaches to reporter fusion?

- gene fusions to measure virulence gene regulation - gene fusions to measure virulence gene regulation by transposon mutagenesis

Model for the Mechanism of Protein Secretion by the Sec-independent T1SS from E. coli that Secretes A-Hemolysin (HLya):

- inner membrane (IM)-spanning ABC transporter (HlyB). - a periplasmic-connecting protein (accessory factor, HlyD). - an outer membrane (OM)-spanning pore protein (TolC).

symptoms of shigellosis? how infectious is it, and how does it spread?

- sexually spread. - highly infectious; low ID50-100-1,000 organisms.

how can ABR in Shigella be transferred?

- showed transfer in vitro & in vivo between multiple drug resistant E. coli & sensitive Shigella. - proposed gene transfer (not multiple mutations) by conjugation as mechanism.

escape from phagocytosis mediated by bacterial toxins that disrupt membranes involves?

1. Degrading membrane lipids 2. Forming pores in membrane

S. pneumoniae: _____ binding to the phosphorylcholine (P-Cho) groups mediating adherence.

15 choline-binding proteins (CBPs)

o 1st genuine cases of community-acquired MRSA (CA-MRSA) infections were reported among individuals in Western Australia in early _____.§ Further outbreaks in late 1990s, early 2000s in patient groups that had not been hospitalized in recent past.

1990s

§ Cationic AMPs sensed by sensor histidine kinase ApsS à phosphorylates cognate response regulator ApsR à genes encoding proteins that modify cell wall Tas & phospholipids in the cell membrane à increase in the positive charge of the cell surface --> repulsion of cationic AMPs.

2-Component Regulatory System ApsS/ApsR

_____ has sensor histidine kinases (SHK): extracellular (gram-positive) or periplasmic (gram-negative) sensor domain, transmembrane domain, a dimerization domain, enzymatic kinase domain. upon sensing a signal, the _____ dimerizes & undergoes autophosphorylation on a His residue of the dimerization domain. _____ is transferred to an Asp residue in the receiver (Rec) domain of the cognate response regulator (RR).

2-Component Regulatory System for Sensing & Transducing Extracellular Signals; SHK; phosphoryl group

§ Spore-containing envelopes mailed to news & government offices; consensus is that it was "non-weaponized" (i.e., not mixed w/ silica nor dispersal agents). § 11 inhalational & 11 cutaneous cases reported; all 5 patients who developed shock w/ inhalational disease died. § Prophylactic antibiotic treatment for many potentially exposed individuals likely mitigated a much higher fatality rate. § Specific source of the contaminated envelopes still unknown. · 2 suspects investigated; no one formally charged/prosecuted.

2001 anthrax outbreak (U.S.)

for S. pneumoniae: _____: antigens from the 23 most common capsular types; safe; efficacy about 60% in elderly but does not work in infants.

23-valent capsular vaccine

CDC estimates that _____ MRSA infections & 11,00 MRSA-associated deaths occur in the U.S. per year.§ Recently categorized by the CDC as a "significant antibiotic-resistant threat."

80,000

basal structure is assembled in the inner & outer membranes, outer membrane channel structure is closed.

A

the _____ of diphtheria toxin (DT): - catalyzes ADP-ribosylation of EF-1 at diphthamide residue (unusual histidine derivative) --> specificity. - transfer of ADP-ribosyl group to EF-2 --> inactivation -> inhibition of polypeptide elongation (protein translation).

A subunit

causes wound & lung infections?

A. baumannii

colonization of _____: - adherence to host cells - resistance to inhibitory agents & conditions of skin & mucosal surfaces - biofilm formation - quorum sensing

A. baumannii

colonizes respiratory tract; causes pneumonia; colonizes skin; invades & infects bloodstream; can cause UTI; can colonize & infect wounds.

A. baumannii

environmental survival of _____: - resistance to desiccation, disinfectants, & antibiotics. - use of various substrates for growth. - biofilm formation on surfaces, equipment, & devices. - quorum sensing for regulation of e.g., biofilm formation.

A. baumannii

infection of _____: - elicitation of inflammatory responses - cytotoxicity - iron acquisition - resistance to serum & competent activation

A. baumannii

o Has been categorized as a "superbug" (along w/ TB & MRSA) because they are extensively drug-resistant. o Also, inherently resistant to disinfectants & various environmental conditions --> hampers decontamination efforts. o Aggressive sterilization & patient isolation required (1 patient = 1 doctor/1 nurse rule). treatments are limited.

A. baumannii

o High incidence among immunocompromised individuals, especially those who have experienced a prolonged (more than 90-day) hospital stay. o Gram-negative rod, aerobic, & non-motile. o Ubiquitous in soil & aquatic environments; can also colonize skin.§ Both colonized wound infections (soldiers) --> Iraq strains brought to U.S. via colonized wounded soldiers --> Walter Reed --> other U.S. hospitals. o Wound infections (primarily), also bloodstream & pneumonia.

A. baumannii

_____ either inactivates the target or causes it to behave abnormally. diphtheria toxin-mediated _____ of the diphthamide residue on EF-2 catalyzed by a glutamic acid (active site of the A domain); nicotinamide is released as a product.

ADP-ribosylation

binding of _____ to membrane receptor protein (HK) --> phosphorelay to RR --> regulation of target genes.

AI2

gram-positive & gram-negative use _____ for interspecies communication; furanosyl borate diester; byproduct of SAM degradation; common to all bacteria; clear indicator of presence of other bacteria; small, hydrophobic, diffusible across cell membrane.

AI2

binding of _____ to membrane receptor protein (HK) --> phosphorelay to RR --> regulation of target genes; 2-component system (TCS)

AIP

gram-positive species (mostly) use _____ for intraspecies communication.

AIP

"_____" genes --> often virulence factors.

Accessory

_____is also an important regulator of biofilm development in S. aureus.o Accumulation of _____ induces biofilm dispersal; naturally occurring agr mutants have been isolated from biofilm infections (agr mutation = _____ biofilm formation).

Agr; AIP; increased

· "Re-discovery" of Penicillin by _____.

Alexander Fleming

in S. epidermidis this two-component system is called _____

ApsS/ApsR

needle components are secreted & assembled; tape measure protein controls needle length.

B

the _____ of diphtheria toxin (DT): recognition subunit that has R domain that binds HB-EGF growth factor (required for cutaneous wound healing).

B subunit

o Cause bacterial resistance to the B-lactam family of antibiotics. o Can be encoded in chromosome, plasmid but also transposable elements. o Cleave beta-lactam ring of beta-lactam antibiotics & inactivates them. o Penicillinase: first known beta-lactamase. o Emergence of methicillin-resistant S. aureus (MRSA).

B-lactamases

inhibit transpeptidation step in peptidoglycan synthesis; bind PBPs; stimulate autolysins. resistance mechanisms: gram-negative outer membrane alterations; porin mutations; B-lactamase; modify target (alteration of PBP). these antibiotics can be used on gram-negative &/or gram-positive (depends on agent)

B-lactams (penicillins, cephalosporins, carbapenems, & monobactams)

causes lung infections?

B. cenocepacia

causes diarrhea & is a risk factor for colorectal cancer?

B. fragilis, ETBF

causes internal abscesses & bacteremia (sepsis)?

B. fragilis, NTBF

o Gram-positive, non-motile, aerobic, facultative anaerobic, large rod-shaped bacterium capable of forming dormant spores. o Found in soil --> herbivore mammals <-- humans.

Bacillus anthracis

spores are extremely stable outside of the host; can be produced in large quantities; spores require refinement.

Bacillus anthracis

Functions Heterogeneity in _____ Systems: § Prep for environmental fluctuations (bet hedging). § More cost-effective way of producing public goods (division of labor). § Loophole for genotypic cooperators when faced w/ non-contributing mutants (cheat protection). § Means to finetune the output of the population (output modulation).

Bacterial Quorum Sensing

first international disarmament treaty (about 176 countries).

Biological & Toxins Weapons Convention

_____ plague pandemic killed about 25 million people (almost 1/3 of the world population) over the course of 5 years.

Black Death

absorbed thru gut & into synapses of peripheral nerves, blocks acetylcholine release.

BoNT

specific for peripheral neurons; toxin binds to ganglioside & protein receptors found only on neuronal cells; bound toxin is internalized & action inhibits neurotransmitter acetylcholine (Ach) release; acetylcholine is involved in initiating an action potential for muscle movement at the neuromuscular junction; leads to paralysis.

BoNT

synthesized & secreted from the bacteria as a 150-kDa protein; cleavage into 2 protein fragments, heavy chain & light chain connected by disulfide bridge; produced as part of an even larger complex containing other proteins beside the toxin; the complex: progenitor toxin, the toxin - derivative toxin (less effective than progenitor toxin given orally, but equally so if injected); endopeptidase (serotype-specific) targets SNARE proteins (mediate synaptic vesicle fusion, Ach release); nontoxic components of progenitor toxin help protect the derivative toxin from stomach acid/proteases.

BoNT

bioterrorism: o Ancient times: poisoning of water wells; arrows dipped in poison; diseased blood. o Medieval times: catapulting diseases corpses. o Smallpox-contaminated blankets given to Native Americans. o WWI: anthrax species, water contaminated w/ _____ --> inhibition of troop movements (directed at animals). § Post-WWI: _____ (1925) - banned bioweapon use (not possession/research, etc.). o WWII thru Cold War: defensive --> offensive bioweapons programs. o 1969: U.S. officially terminated its offensive bioweapons program (back to defensive measures only). o _____ (1975): first international disarmament treaty (about 176 countries).

Burkholderia mollei; Geneva protocol; Biological & Toxins Weapons Convention

after the needle is fully assembled, tip complex components are secreted & assembled.

C

Normal Neurotransmission at Synapse of Neuromuscular Junctions: 1. Binding of the _____ portion of the heavy chain to presynaptic membrane receptors. 2. Uptake of the _____ into a synaptic endocytic vesicle. 3. _____ of the catalytic light chain to the cytosol. 4. BoNT-LC-mediated proteolytic cleavage of _____ involved in synaptic vesicle fusion w/ the plasma membrane --> no membrane fusion --> release of the neurotransmitter, acetylcholine (Ach) is not present --> no muscle contractions.

C-terminal; toxin; Translocation; neuron-specific SNARE proteins

"______" located on chromosome 7; mutation results in production of a defective transmembrane conductance regulator protein.

CF gene

used for gene editing; clustered regularly interspaced short palindromic repeats à edit genome to study the function of genes, e.g., delete a gene or activation.

CRISPR system

Normal Neurotransmission at Synapse of Neuromuscular Junctions: membrane fusion is blocked until depolarization of the nerve terminal membrane --> _____ influx --> conformational changes that initiate membrane fusion --> release of neurotransmitter into synaptic cleft.

Ca2+

generation of stimulus signals: - _____ transmits signals to the flagellar motors. - _____ controls their lifetime. - _____ (methyltransferase) & _____ (methylesterase) regulate MCP methylation state.

CheY; CheZ; CheR; CheB

causes botulism (food poisoning), infant botulism, wound botulism; species is an anaerobic, gram-positive rod; canned foods, honey improperly sterilized, contaminated w/ spores; germination of spores in anaerobic environment, when BoNT produced.

Clostridium botulinum

causative agent of diphtheria & skin infections.

Corynebacterium diphtheriae

- replicates within specialized vacuoles, lysosomal cathepsin D, & acid phosphatase accumulate in bacteria-containing phagosomes, full lysosomal fusion is delated. - acidic environment (pH ~ 5) used to activate metabolic activity; specific proteins protect the bacterium from phagocytic oxidative burst.

Coxiella burnetii (tickborne Q fever)

S. aureus virulence is also strongly influenced by metabolism. o Example 2: _____ § S. aureus can make 2 types of cytochromes, encoded by qox & cyd operons. § Cellular respiration § These 2 different cytochromes impact S. aureus virulence in an organ-specific manner.

Cytochromes

upon contact w/ the host cell membrane --> formation of translocator pore in host cell membrane.

D

disrupt cell membranes by intercalating in them

DACs

fiery pyroptosis enhances inflammation: - _____: danger-associated molecular patterns such as intracellular ATP levels. - _____: pathogen-associated molecular patterns such as LPS.

DAMPs; PAMPs

Secreted enzymes that degrade pus

DNases, proteases

causes bacteremia?

E. chaffeensis

Enterobacteriaceae resistant to carbapenems are _____ & _____. *some bacteria in this family are resistant to nearly all antibiotics, leaving more toxic or less effective treatment options.

E. coli & K. pneumoniae

avoiding the complement system & phagocytosis; evasion of pili type switching to escape antibody-based host responses. _____ & _____ change pilin types by antigenic variation mechanisms --> impossible to mount an effective antibody response that prevents colonization or allows for bacterial clearance.

E. coli & Neisseria gonorrheae

causes diarrhea?

E. coli, EIEC

causes neonatal meningitis?

E. coli, K1 strains

causes UTIs?

E. coli, UPEC

o MDR pathogens that evolved multiple mechanisms for escaping antibiotics.o Typically, associated w/ healthcare settings.o Enormous financial & resource burden on global healthcare. o Cases of community-acquired infections.

ESKAPE pathogens

o Commensal bacterium from GI tract. o Cause of hospital-acquired bacteremia, UTIs, wound infections, & catheter-associated infections. o Hospital isolates acquired accessory genes that are not present in gut isolates.

Enterococcus faecium

In 1897, _____ (a French physician) published his thesis in which he described antimicrobial property of mold.

Ernest Duchesne

P. aeruginosa virulence factor: AB toxin that ADP-ribosylates EF-2; inhibits host cell protein synthesis; causes cell death.

ExoA

P. aeruginosa virulence factor: these are the T3SS effector proteins that cause cytotoxicity & inflammation.

ExoS, ExoT, ExoU, & ExoY

WWI: anthrax species, water contaminated w/ Burkholderia mollei à inhibition of troop movements (directed at animals). § Post-WWI: _____ (1925) - banned bioweapon use (not possession/research, etc.).

Geneva protocol

types of infections S. aureus is causing?

HA-MRSA, CA-MRSA, & LA-MRSA

degrade hyaluronic acid in connective tissue.

Hyaluronidases

_____ expression is dependent on temperature; _____ is responsible for activating yop transcription at 37 degrees.

IcrF; LcrF

host defense against S. pneumoniae in bloodstream: _____ antibodies, complement proteins, _____ protein (CRP), & _____ peptide (SAP).

IgM; C reactive; serum amyloid

______ forms "tip complex" w/ IpaD & modulates secretion.

IpaB

induces actin polymerization & filopodia formation.

IpaC

o Paleo-genomic studies confirm presence of Y. pestis in 2 historically recorded plague pandemics: § _____, 6-8th centuries § _____ (14-18th centuries) including the famous "Black Death."

Justinian's Plague; 2nd Plague Pandemic

causes UTIs, septicemia, & liver abscess?

K. pneumoniae

o Bacteria spread on agar plates. o Wafer discs or stripes w/ different concentration of the antibiotic are placed on the agar. o Observe bacterial growth on plate. Susceptibility

Kirby-Bauer Assay

how was the virulence plasmid discovered in Shigella?

Koch's Postulates: - loss of 180 kb plasmid is associated w/ T to O transition & loss of virulence in S. sonnei. - marked plasmid w/ Tn3 (ApR); transferred to plasmid-cured S. sonnei; restored virulence. - pWR110 transferred into E. coli K-12 makes strain invasive. - all Shigella & EIEC have a virulence plasmid; homologous sequences & functional interchangeability.

has pore-forming cytotoxins: - pore-forming hemolysin, listeriolysin O (LLO) - a gram-positive rod; motile; facultative anaerobe. - causes foodborne gastroenteritis (raw foods/unpasteurized milk) - can survive at 4 degrees C ("cold enrichment" of cultures). - bacteremia (immunocompromised/pregnant patients) --> meningitis - infection (in utero or birth canal --> sepsis or infection/meningitis). - 100-1000x more common in AIDS patients/suppressed cell-mediated immunity. - antibiotic treatment (ampicillin) for meningitis.

L. monocytogenes

in early 21st century, a novel pig-associated strain of MRSA identified: livestock-acquired MRSA (_____) since found in cattle, dogs, & humans.§ Frequently shared between animals & humans; capable of symptomatic infections in both species.

LA-MRSA

NETosis: Neutrophil Extracellular Traps, Immobilizes, & Kills Bacteria: bacterial _____ induces cytoskeletal rearrangements upregulating reactive oxygen species generation & antimicrobial granule release.

LPS

P. aeruginosa virulence factor: endotoxic shock, sepsis, serum resistance.

LPS

o Released from cell membrane upon cell lysis. o Interacts w/ TLRs on immune cells. § TLR4

LPS

examples of endotoxins?

LPS, LTA, & phosphatidylglycerol (PG)

LPS: _____ = toxicity; polysaccharide = highly variable; immunogenicity.

Lipid A

i. Invades intestinal cells ii. Gastroenteritis iii. Can cross blood-brain & blood-placental barriers in immunocompromised persons.

Listeria monocytogenes

P. aeruginosa virulence factor: antibiotic efflux pump (MexEF-OprMN) & its regular (MexT); confers antibiotic resistance.

MDR efflux system (MexEF, OprMN, & MexT)

oral vaccine development: - injected viral proteins are processed & transported to the cell surface as peptides bound to _____ molecules, where they can stimulate a cellular immune response.

MHC class I

in the USA, _____ is among one of the leading causes of death by any single infectious agent.

MRSA

lowest [antibiotic] that will kill bacteria.

Minimum Bactericidal Concentration (MBC)

o lowest [antibiotic] that will prevent bacterial growth. dilution susceptibility assay.

Minimum Inhibitory Concentration (MIC)

_____: ESX-1 thru ESX-5 systems - some important in virulence, some important for growth (e.g., iron acquisition).

Mycobacteria

secretion signal for sec system?

N-terminal signal peptide

secretion signal for TAT system?

N-terminal signal peptide often containing 2 arginine residues

NETosis: Neutrophil Extracellular Traps, Immobilizes, & Kills Bacteria: virulent enteropathogenic bacteria induce _____ formation, whereas nonvirulent probiotic bacteria do not.

NET

NETosis: Neutrophil Extracellular Traps, Immobilizes, & Kills Bacteria: o Activated neutrophils can undergo NET formation termed: _____ a unique form of cell death.

NETosis

_____ is highly resistant to sulfonamides, penicillin, tetracycline, fluoroquinolones, & the only recommended antibiotics to treat it are ceftriaxone and azithromycin.

Neisseria gonorrhoeae

i. Mediate tighter binding to host cell once initial pili binding has occurred. ii. Recognize carbohydrates or protein host cell receptors. iii. Listeria monocytogenes has 2 surface proteins internalins A & B (lnIA & lnIB) to bind to host cells.

Nonfimbrial Adhesins (gram-positive)

cellular signaling molecules can be located on the _____, _____, or _____.

OM (outer membrane); PG peptidoglycan layer of cell wall); CM (cytoplasmic membrane)

know that Shigella destroys macrophages and by what mechanism, function of PMNs and epithelial cells in Shigella infection.

OspC1 & OspD3 block apoptosis & necroptosis in epithelial cells. Shigella effectors block cell death pathway to allow host cell to live longer.

ESKAPE pathogen associated with... - lung (cystic fibrosis or "CF") - skin (wound & burn infections, chronic wounds) - eye - bone, heart, UTI, meningitis

P. aeruginosa

ESKAPE pathogen that is ubiquitous in soil, water, & plants; adapts from aerobic to anaerobic conditions easily. - biofilm growth: variety of factors.

P. aeruginosa

causes lung infections in cystic fibrosis patients; wound & burn infections; ventilator-associated infections; & catheter-associated infections?

P. aeruginosa

causes periodontal disease & internal infections?

P. gingivalis

modes of resistance to transpeptidase inhibitors: emergence of _____ w/ low affinity for penicillin or _____ production --> resistance. e.g., penicillin-binding protein 2A (PBP2A) causes resistance in methicillin-resistant S. aureus (MRSA). some bacteria lack cell wall - insensitive to beta-lactam antibiotics.

PBPs; beta-lactamase

for S. pneumoniae: 13-valent conjugated vaccine made in 2010.

PCV-13

for S. pneumoniae: o _____, pneumococcal conjugated 7-valent vaccine (2000): covalent linkage between carbohydrates to peptide antigens à induction of MHCII-mediated T-cell-dependent responses to the carbohydrates; works in infants; issues w/ use in developing countries, because it is expensive.

PCV-7

IL-1beta drives recruitment of neutrophils & macrophages undergoing pyroptosis: _____ (Pore-induced Intracellular Traps): - Immobilize live bacteria. - Bacteria are destroyed when apoptotic cells are phagocytosed & degrade by recruited neutrophils.

PITs

IL-1beta drives recruitment of neutrophils & macrophages undergoing pyroptosis: _____.

PITs

o _____ (distribution of antimicrobial compound in host's body) § Toxicity dictates internal vs. external use · Absorption, dosage, distribution/dissemination, route of administration, stability.

Pharmacokinetics

§ Antimicrobial agent specificity for bacterial target w/o affecting mammalian cells (differential toxicity). § "Risk" vs. "reward"

Pharmacokinetics (side effects)

Yersinia post-translational regulation of virulence: the _____, which detects low levels of pH & low levels of magnesium also affects RovA expression.

PhoQ-PhoP two-component system

in lower airways recognized by pattern-recognition receptors (e.g., TLRs) on epithelial cells & alveolar macrophages.

Pneumococci

mediates binding to integrins (transmembrane proteins that maintain cell-cell interactions, cell-ECM interactions, & intracellular signaling (cellular invagination)).

RGD (Arg-Gly-Asp) motif

used to turn off/silence specific host genes à C. elegans, D. melanogaster high-throughput screening (Nobel Prize, 2016).

RNA interference (RNAi)

used to compare host gene expression changes in response to infection.

RNA microarray

used to compare changes in global protein production &/or indicator proteins ("biomarkers"; i.e., pro-inflammatory cytokines).

RNA-seq

- enables the screening of large libraries of eukaryotic host genes. - gene-specific dsRNA was able to efficiently silence specific genes (better than sense or anti-sense RNA). - used to turn off/silence specific host genes à C. elegans, D. melanogaster high-throughput screening (Nobel Prize, 2016).

RNAi

Yersinia post-translational regulation of virulence: o _____ controls switch between environmental survivability & virulence.

RovA

_____ can cause "flesh-eating" skin infections (necrotizing fasciitis).

S. aureus

can infect nearly every tissue & organ system in the human body; causes boils, skin/soft tissue infection, abscess. sepsis --> bacterium can spread to & grow in nearly all organ systems (kidneys, heart, bone, spleen, liver, brain abscess, etc.); also, a major cause of biofilm infections; growth-phase-dependent expression of many virulence factors regulated by the Agr QS system; biofilm formation also negatively regulated by Agr.

S. aureus

iron acquisition in gram-positive bacteria: _____ uses siderophores exogenously produced by other bacteria to take up iron thru the ABC transporter system.

S. aureus

o 20% persistent colonization; 30% transiently colonized. § Primarily nares; also groin & GI tract. § Colonization increase the risk for subsequent infection. § Those w/ _____ infections are generally infected w/ their own colonizing strain. o Emergence of antibiotic resistant strains § MRSA: both community- & hospital-acquired strains. § VRSA: not a serious problem yet.

S. aureus

effector of system is an untranslated RNA molecule "RNAIII"; regulates at post-transcriptional level --> base pairs w/ target mRNAs: stabilization/destabilization of target mRNA & access to RBS (target gene).

S. aureus Agr QS System

how does S. aureus biofilm affect proinflammatory responses?

S. aureus biofilms appear to be capable of attenuating traditional host proinflammatory responses, which may explain why biofilm infections persist in an immunocompetent host.

o Causes pneumonia, bacteremia, meningitis, & otitis media. o Colonizes nasopharynx. o Colonization often asymptomatic: reservoir for transmission of S. pneumoniae among humans. o Most people are colonized by 1 serotype of S. pneumoniae at a time (antibacterial peptides, pneumocins). o Primarily extracellular pathogen. o Inflammatory responses; can breach epithelial cell layers to reach bloodstream.

S. pneumoniae

o Recruitment of PMNs (e.g., C5a, galectin-3, pneumolysin Ply).

S. pneumoniae

Mechanism of Protein Secretion by the _____: autotransporter has multiple domains: 1. N-terminal Sec signal sequence 2. Passenger (P) domain 3. Linker (L) region 4. C-terminal beta domain ii. Translocator domain of the protein inserts into the OM & facilitates surface localization of the passenger domain. iii. Some autotransporters undergo autoproteolytic cleavage.

Sec-dependent T5SS

Mechanism of Protein Secretion by the _____ from E. coli that Secretes A-Hemolysin (HLya): o Inner membrane (IM)-spanning ABC transporter (HlyB). o A periplasmic-connecting protein (accessory factor, HlyD). o An outer membrane (OM)-spanning pore protein (TolC).

Sec-independent T1SS

Sec Co-translational System: the _____ does/is the following: 1. Recognizes nascent polypeptides possessing signal sequences as emerge from ribosome. 2. SRP-ribosome-substrate complex targeted to membrane via affinity of SRP for the SRP receptor (SR). 3. Universally conserved. 4. Important function in Sec substrate recognition & targeting. 5. Composed of RNA & proteins. 6. Signal peptide recognized by SRP particle. 7. SRP-bound peptide delivered to SECYEG complex w/ help of SRP receptor FtsY. 8. Some proteins go via alternate route involving YidC alone or w/ help of SecYEG complex. 9. A signal peptidase (SPase) cleaves signal sequence à mature protein is released.

Signal Recognition Particle (SRP)

S. aureus Intracellular Lifestyle o _____: § Stable or unstable (reversible) § Stable phenotype from genetic defects in electron transport chain cofactors or thymidine biosynthesis. § Reduce virulence § Increased antibiotic tolerance § Avoidance of immune system o _____: § Bacterial cell surface fibronectin-binding protein à host fibronectin --> host cell integrin receptor

Small-colony Variants (SCVs); Non-phagocytic internalization

S. aureus virulence is also strongly influenced by metabolism. o Example 1: ____ § 2-component System (SrrB = membrane sensor protein, SrrA = cytosolic response regulator) § Upregulates expression of anaerobic metabolism genes in response to hypoxia. § Also, important of resistance to nitric oxide. § Mutation of this regulator impacts virulence in vivo.

SrrAB

types of pore-forming toxins?

Staphylococcal leukotoxins, Staphylococcal leukocidins, hemolysins, streptolysin O (SLO), streptolysin S (SLS), perfringolysin O (PFO), listeriolysin O (LLO)

surface-associated multicellular growth lifestyles of bacteria; is not motile.

Staphylococcus

o Binds to plastic implants --> biofilms extend into tissue --> shedding bacteria into the bloodstream --> sepsis.

Staphylococcus epidermidis

o Biofilms: adhesive proteins, exopolysaccharides (PGA), & nucleic acids.

Staphylococcus epidermidis

o Capsule-like exopolymer (poly-y-glutamic acid, PGA) made under high salt --> protection from osmotic stress, biofilm, protection against AMPs & phagocytosis.

Staphylococcus epidermidis

o Forms robust biofilms (protection against innate immunity), difficult to eliminate using antibiotics (natural resistance).

Staphylococcus epidermidis

o Found primarily on human skin in almost all people. o Protects skin from pathogenic species like S. aureus. o Coagulase-negative Staphylococcus (CoNS) species (S. aureus coagulase catalyzes conversion of fibrinogen to fibrin à blood clotting). o Issue for implanted abiotic medical devices, indwelling catheters, pacemakers, or join prostheses.

Staphylococcus epidermidis

Which secretion systems inject proteins/molecules directly inside the host cell? a. _____, _____, _____ & _____ (Group A Strep) - Injectisome

T1, T3, T4, & Cytolysin-mediated Translocation (CMT) in S. pyogenes

proteins cross directly from the cytoplasm to the cell surface, bypassing the general Sec system & periplasm; capable of transporting proteins up to 800 kDa out of the cell. 3-partite system: ATP-binding cassette (ABAC) transporter or proton-antiporter, adaptor protein, & outer membrane pore; secreted protein binds to the ABC transporter via C-terminal signal sequence; signal sequence is not cleaved during export. no stable periplasmic intermediate; secretion of cytotoxin (RTX family), cell-surface proteins, proteases, lipases, & others (e.g., alpha-hemolysin (HlyA) from E. coli secreted via _____.

T1SS

_____ deliver effector proteins into the host cell cytoplasm in a Sec-independent manner.

T3SS

chaperone proteins guide _____ effector proteins to the _____ apparatus.

T3SS

export of specific proteins w/ short N-terminal tag-enrichment of soluble proteins w/ no purification steps; production of biopolymer-forming proteins; delivery of immunomodulatory cytokines.

T3SS

o Central slices from denoised cryo-electron tomograms of plunge-frozen C. trachomatis elementary bodies & S. enterica minicells. o Central slices thru sub-tomogram averages of the host-free T3SS from C. trachomatis & S. enterica. o Individual components are labeled in the corresponding 3D surface rendering.

T3SS

oral vaccine development: - genetically fused viral target protein to an N-terminal signal sequence to facilitate _____ secretion & injection into the host cytoplasm.

T3SS

_____ & _____ similarities: o System components (about 20) structurally, genetically, & functionally related to flagella. o Have a large basal body complex embedded in the inner membrane. o ATPases facilitate release of the chaperones & unfolding of the effectors for secretion. o Refolding upon exit of the needle - help in facilitating the transport process. o Switch proteins regulate which substrates are secreted. o Effector proteins only secreted upon contact w/ host cell.

T3SS & flagella

o Directly injects virulence proteins (e.g., Yops of Yersinia) into cytosol of host cell.

T3SS (injectisomes)

o Directly injects virulence proteins (e.g., Yops of Yersinia) into cytosol of host cell. o Can enable bacteria to invade host e.g., by rearranging the cytoskeleton & ruffling the membrane of the host.

T3SS (injectisomes)

Yersinia pYV Virulence Plasmid i. pYV encodes virulence proteins & a _____. ii. _____ & temperature regulated.

T3SS; Calcium

the _____ & contractile phage structural components: § Phage attaches to bacterial OM from the extracellular space, while the T6SS assembles within the IM. § If a target membrane of a neighboring eukaryotic or bacterial cell is close, the _____spike will cross the TM to deliver effector molecules into adjacent cell.

T6SS

EsxA & EsxB: § Proteins secreted via _____. § T cell-antigenic targets required for virulence. § Pore-forming toxins involved in escape from macrophage phagosomes. § Present only in the pathogenic strain.

T7SS

_____ present in Mycobacterium, Corynebacteriales, S. aureus, Bacillus anthracis, & some L. monocytogenes.

T7SS

o Mycomembrane around Mycobacterium (also in Corynebacteriales) contains a hydrophobic layer, exopolysaccharide capsule layer further covers the mycomembrane à extracellular protein transport is an issue.

T7SS

the TatABC translocon is found in the cytoplasmic membrane of both gram-positive & gram-negative bacteria; it transports fully folded proteins, including bound cofactor ligands from cytoplasm to extracellular milieu in gram-positive bacteria or to the periplasm in gram-negative bacteria.

TAT system

a series of increasing concentrations of antibiotic is prepared in the culture medium; each tube is inoculated, and incubation can proceed. o Growth (turbidity) occurs in those tubes w/ antibiotic concentrations below the MIC; the lower the MIC, the more potent.

Tube Dilution for MIC Determination

Membrane-disrupting Toxins; o Disrupting the integrity of the target cell's plasma membranes. o Frequently called "hemolysins" --> red blood cells are a convenient cell type to use as an assay system. o Also called cytolysins --> can target a variety of cell types (target the cell membrane).

Type 2 Toxins

o Found in several pathogens: P. aeruginosa, enteroaggregative E. coli, S. typhimurium, V. cholerae, & Yersinia pestis. o Multicomponent systems: 12-25 subunits. o Evolutionarily related to bacteriophage T4 tail & baseplate. o Role in pathogenesis, defense against simple eukaryotic predators & interbacterial interactions.

Type VI Secretion System

_____ strain: skin & soft-tissue infections (outbreaks in prisons, locker rooms/sports teams, military); now, the predominant strain.

USA300

_____ strain: highly associated w/ necrotizing pneumonia or pulmonary abscesses & sepsis.

USA400

blocks DNA replication & transcription by damaging DNA.

UV radiation

o Gram-negative bacterium; motile; halophilic. o Causative agent of cholera. § Voluminous, watery diarrhea; life-threatening (dehydration). o Fecal-oral transmission; aquatic environments natural reservoir (algae, copepods, crustacean shells). o Penetration of intestinal epithelium facilitated by flagellar motility, mucinase. o Mortality rate w/o treatment 25-50%.

V. cholerae

____ is transmitted from contaminated pork whereas Y. pseudotuberculosis is primarily transmitted thru contaminated produce.

Y. enterocolitica

_____ is most like Y. pestis; about 97% genetic identity in over 75% of all encoded genes.

Y. pseudotuberculosis

both _____ & _____ induce gastric enteritis, diarrhea, & mesenteric lymphadenitis.

Y. pseudotuberculosis; Y. enterocolitica

_____ encodes 3 major adherins: invasion, YadA, & Ail.

Yersinia

first discovered by Alexandre Yersin during a plague outbreak in Honk Kong, 1894.

Yersinia

i. _____ adheres to cells by recognizing alpha-5-beta-l integrin thru bacterial protein invasion.

Yersinia

inhibits IL-1beta production by blocking biosynthesis of the bioactive lipids.

Yersinia

o Etiological agent of plague. o First discovered by Alexandre Yersin during a plague outbreak in Honk Kong, 1894.

Yersinia pestis

requires flea as a vehicle for transmission; bacterium sensitive to antibiotics; was used as a bioweapon during WWII.

Yersinia pestis

family _____ consists of gram-negative, rod-shaped bacterial pathogens Y. pestis, Y. pseudotuberculosis, & Y. enterocolitica; ecological opportunity & evolution of flea borne transmission of Yersinia.

Yersiniae

caused by Y. enterocolitica & Y. pseudotuberculosis o CDC estimates Y. enterocolitica & Y. pseudotuberculosis causes 117k illnesses, 640 hospitalizations, & 35 deaths in U.S. annually.o Children are more likely to become infected than adults.

Yersiniosis

_____ translocates YopO/E/H/J/T/M.

YopB/D

_____ induces apoptosis in macrophages & diminishes chemotaxis of neutrophils.

YopJ

Yersinia outer membrane proteins are secreted thru the T3SS into host cytosol.

Yops

_____ inhibit cytokine production & bacterial uptake by inhibiting host signaling pathways.

Yops

_____ interact w/ host proteins to interfere w/ host cytoskeleton, cytokine biosynthesis, & inflammasome activation.

Yops

i. Secretion substrates are delivered into periplasmic space by Sec or TAT systems. ii. Inner membrane complex assembles opposite outer membrane pore; the pseudopilin extends from inner membrane complex, while the secretion substrates bind to the tip of pseudopilin. iii. ATP hydrolysis by a cytoplasmic ATPase drives incorporation of pilin subunits embedded in the inner membrane into the pseudopilus. iv. Extension of the pseudopilus pushes secretion substrates out of the cell.

a. Sec-dependent T2SS

found in gram-positive & gram-negative bacteria but not found in all species; used for folded proteins, some proteins contain co-factors; proteins targeted to membrane-embedded translocase by N-terminal twin-arginine signal sequence: polar N-terminal region of variable length followed by a region w/ motif SRRXFLK, & hydrophobic region of 12-20 AA. precursor proteins bind to TatBC thru TAT signal sequences; TatA is recruited to the resulting complex & thru forms a large pore; major conformational change (role of proton electrochemical gradient) induces transport of the protein across the membrane; TAT signal sequence is then cleaved by a surface signal peptidase; mature protein is released.

a. Tat-Twin Arginine System

hallmarks of the virulence of Shigella?

a. invasion of (colonic) epithelial cells b. intracellular replication c. intercellular spread d. inflammation/anti-inflammation e. gene regulation (temperature & intracellular environment)

in vivo models of Shigella?

a. sereny test (guinea pig) - invasion, multiplication, spread, inflammation b. mouse lung model - invasion, multiplication, spread, death c. ligated rabbit ileal loop - fluid accumulation induced by bacteria (or toxin) d. guinea pig intrarectal challenge - severe, acute rectocolitis; dysentery; & invasion & colonization in colon e. monkey infection - dysentery & lesions in colon resemble human disease

bacterial quorum sensing: small, hydrophobic, membrane-diffusible molecules; synthesized from S-adenosyl methionine (SAM) & a fatty acid precursor, acyl-ACP (acyl carrier protein).

acyl-homoserine lactones (AHLs)

the _____ of diphtheria toxin (DT): T domain (translocation domain) facilitates translocation of A subunit across membrane into cytosol.

additional functional domain

essential step for most pathogens; usually involved in mediating host cell targeting, cell-cell interactions, or signal transduction.

adherence

Yersinia: _____ expression is regulated by temperature in Yersiniae ssp. Importance of temperature at 26 degrees C & at 37 degrees C, the flagellum machinery is degraded à expression of adherins to establish attachment.

adherin

outer membrane proteins that bind to host cells such as epithelial cells, platelets, & mucus membranes

adhesins

S. pneumoniae: Mechanisms to adhere to the apical surface of epithelial cells: pili, _____ [pneumococcal surface adhesion (PsaA) binding to cadherin, pneumococcal adherence & _____ (PavA) binding to fibronectin, etc.]

adhesins; virulence factor A

S. aureus cell-surface _____ highly upregulated during exponential growth phase; secreted toxins & tissue-degrading enzymes upregulated during stationary phase.

adhesions

S. aureus virulence factor expression is coordinately regulated by the _____.

agr quorum-sensing system

denature proteins.

alcohols

P. aeruginosa virulence factor: adherence, protection from dehydration, antiphagocytic, protection of biofilm from host immune system.

alginate

form epoxide bridges that inactivate proteins.

alkylating agents (formaldehyde, ethylene oxide)

function of actin tail (intracellular motility), (proteins in Shigella and Listeria play same function)?

allows for intracellular movement; forms protrusion at cell surface to get inside of the cell.

bind 16S rRNA in 30S subunit of bacterial ribosome. resistance mechanisms: inactivation of antibiotic by adding groups; mutation in 16S rRNA genes. broadly bactericidal.

aminoglycosides

o All forms of disease treatable w/ antibiotics; "the sooner, the better," (especially for inhalational or GI anthrax). o Vaccine available but recommended only for certain at-risk adult groups (i.e., military, researchers, etc.). o Anti-toxin strategies still under investigation.

anthrax

o easily found in nature; can be produced in a lab; & can last for a long time in the environment. o Can be released quietly & without anyone knowing. o Microscopic _____ can be put into powders, sprays, food, & water; invisible, odorless, & tasteless. o has been used as a "weapon" before.

anthrax spores

bacterial strategies against host AMPs (peptides)? i. Capsule (limits diffusion) ii. LPS (negative charge à binds AMPs) iii. Modification of teichoic acids or phospholipid head groups in gram-positive bacteria (positively charged AA). iv. AMP peptidases (degradation of defensins) v. Cytoplasmic proteins that counter permeabilizing effects of AMPs.

anti-AMPs

transport of antibiotic outside of cell.

antibiotic efflux

mutational alteration or enzymatic modification of antibiotic target.

antibiotic target modification

protection of antibiotic action target from antibiotic-binding.

antibiotic target protection

replacement or substitution of antibiotic action target.

antibiotic target replacement

o applied to living skin or tissue. § Often contain diluted disinfectants. § Often also active against viruses, fungi, protozoa. § Often several targets in bacterial cell. § Most effective against actively growing bacteria. § In general, resistance mechanisms poorly understood relative to antibiotics. · Membrane-active agents less effective against gram-negative bacteria. · Membrane pumps (quaternary ammonium cation resistance in staphylococci).

antiseptics

quorum sensing: direct/indirect activation of a cognate receptor protein by the _____ --> modulation of specific set of genes; usually produced under positive regulatory feedback control; can sense population densities of "self" (within same species) as well as "non-self" (other species).

autoinducer

small, hydrophilic post translationally modified peptides --> cannot be transported across cell membrane; retained in extracellular environment.

autoinducer oligopeptide (AIP)

quorum sensing: use of small diffusible signaling molecules - _____ - role of the positive regulatory feedback control.

autoinducers

small, diffusible signaling molecules ("_____") used to coordinate activities of bacteria as a group.

autoinducers

_____ inhibits lip-PP --> p Lipid in the peptidoglycan synthesis.

bacitracin

endotoxin (LPS)

bacterial cell wall component that binds toll-like receptors; located on chromosome; found in gram-negative bacteria.

lipoteichoic acid (LTA)

bacterial cell wall component that binds toll-like receptors; located on chromosome; found in gram-positive bacteria.

what is the function of type three secretion system in Shigella?

bacterial entry: - target host-cell membrane; form pores. - target regulatory/structural targets in hosts.

reasons for resistance: agriculture, use of antibiotics, caused by genome plasticity in bacteria, societal factors, travel?

bacterial genome plasticity; inappropriate bacterial prescriptions; agricultural antibiotics; international travel; crowding, homelessness, poor sanitation/nutrition

peptidoglycan (PG)

bacterial membrane surface coating component that binds toll-like receptors; located on chromosome; found in all bacteria.

antimicrobial compounds that kill bacteria; best for patients w/ compromised immune systems.

bactericidal

antimicrobial compounds that inhibit bacterial growth; bacteria can frequently recover once treatment is removed; best used in patients w/ intact immune systems.

bacteriostatic

_____ inhibitors can be used in addition to beta-lactams, bc cause bacterial resistance to the B-lactam family of antibiotics.

beta-lactamase

tracheal cytotoxin (TCT)

binds toll-like receptors; a bacterial PG component; produced by Bordetella (gram-negative) species.

a multicellular community of bacteria encompassed in a protective matrix; can be mediated by an extracellular polysaccharide (EPS) slime; can contain proteins & eDNA; increased resistance to antibiotics & immune system.

biofilm

many infections are the result of _____ growth (dental plaque/periodontal diseases, endocarditis, surgical implant & indwelling medical device infection, CF lung infection); Legionnaires' Disease, which is biofilm in AC or other abiotic surface as source of aerosolized bacteria.

biofilm

visualize bacteria or the host molecules during infection.

biphotonic imaging

introduction into water/food supplies; difficulty in initial diagnosis; relative ease in acquisition; potential bioweapon.

botulinum neurotoxin

leads to flaccid paralysis, swallowing, vision problems, & affected breathing.

botulism

potential limitations of transposon mutagenesis?

can carry transcriptional terminators --> polar effects on downstream gene expression (operon) can only be used to identify non-essential genes (disruption of essential gene by transposon à death of clone).

S. pneumoniae: _____ prevents entrapment in nasal mucus --> bacteria reach epithelial cells lining the nasopharynx.

capsule

S. pneumoniae: sugar transporters, _____ biosynthetic enzymes, the pore-forming toxin _____, & _____ lyase (degrades hyaluronic acid polysaccharide in extracellular matrix).

capsule; pneumolysin; hyaluronate

bacteria on CDC list as urgent threats?

carbapenem-resistant Acinetobacter, C. difficile, carbapenem-resistant Enterobacteriaceae, drug-resistant Neisseria gonorrhoeae

Yersinia post-translational regulation of virulence: nutrient availability also effects RovA expression by _____ as well as catabolite repression system (Crp).

carbon storage regulator system (Csr)

oral vaccine development: - attenuated versions of the intracellular bacterium Salmonella typhimurium can serve as "______" of genes from pathogens/viruses.

carriers

only recommended antibiotics to treat Neisseria gonorrhoeae are _____ and _____.

ceftriaxone; azithromycin

type of protein exotoxin (type 2) that pokes holes in membranes --> influx of water into cells; interaction w/ host cell receptor dictates toxin specificity; membrane insertion often facilitates by low pH --> change to protein structure à membrane penetration.

channel-forming/pore-forming Toxins

pili-mediated attachment to GI epithelium, coregulated w/ _____ toxin production (ADP-ribosylase --> Gs protein (host cell adenylate cyclase protein; high cAMP levels à loss of ion flow control --> extreme water loss à diarrhea, dehydration). o "Rice water stool" - mucus, epithelial cells high concentration of V. cholerae.

cholera

NETosis: Neutrophil Extracellular Traps, Immobilizes, & Kills Bacteria: _____ decondensation & extrusion thru pores binds & immobilizes bacteria.

chromatin

P. aeruginosa biofilms --> _____ (inability of ciliated cells to move & remove mucus from the lungs).

ciliary dyskinesia

DNA gyrase inhibitor

ciprofloxacin, novobiocin

use of the plaque assay for the measurement in intracellular spread of Shigella?

clones fail to produce positive plaque assay or sereny test.

express virulence in a non-virulent strain of gram-negative bacteria:

cloning fragments of genomic DNA from an invasive Salmonella strain into a lab strain of E. coli; clones of E. coli invade tissue culture cells.

express virulence in a non-virulent strain of gram-positive bacteria:

cloning the gene for the hemolysin listeriolysin O (LLO) from Listeria monocytogenes into a lab strain of Bacillus subtilis: B. subtilis escapes from host phagosome & grows in cytoplasm.

one of the 2 major routes of the sec translocation system; signal recognition particle or SRP-mediated; predominant GSP pathway in eukaryotes & haloarchaea.

co-translational

a wildtype copy of the transposon-disrupted gene is reintroduced at a 2nd, ectopic site (plasmid or at a genetically neutral site on the chromosome) in the mutant bacterium; used to restore gene expression. Can distinguish polar effects on downstream genes in operons

complementation

disease of abnormal electrolyte transport & mucous secretion from exocrine glands & secretory epithelia; caused by P. aeruginosa. o Mucus obstructs the airway & inhibits ciliary movement --> coughing & wheezing. o Interference w/ the ciliated cell defenses of the airway --> bacteria trapped in mucus --> colonization --> biofilm. o Release of neutrophil extracellular traps (NETs) to trap bacteria. o Chronic infection can lead to early death.

cystic fibrosis (CF)

know that Shigella avoids autophagy and survives in the ______ of the host cell, not vacuole.

cytoplasm

E. coli receptors employ _____ signaling proteins: CheW & CheA.

cytoplasmic

effective host defense for bacterial escape from phagocytosis?

cytotoxic T cell (CD8+) response or the natural killer (NK) cell response (via MHCI-antigen recognition) (activated macrophages might not be effective)

after stationary phase comes?

death phase

i. Cationic, multiple cysteine residues. ii. Interacts w/ negatively charged bacterial cell membrane; depolarization &/or pore formation. iii. Must diffuse thru outer membrane (gram-negative) or cell wall (gram-positive). iv. host factors, not bacterial factors!!

defensins (AMPs)

disadvantage of chemical/UV mutagensis?

difficult to identify mutations (not marked); possibly more than one "hit" per strain.

aerosol inhalation or via touching open ulcers/sores; colonization of back of throat; production of _____ kills cells, causes inflammation, & fibrin accumulation; lymph node swelling, edema in neck; children at highest risk for disease.

diphtheria

can enter bloodstream & affect other organs (heart, CNS) --> respiratory paralysis & heart failure.

diphtheria

antibodies against B subunit of toxin, raised in horses; physically interfere w/ binding to target cells; passive immunization; effective in treatment of disease.

diphtheria anti-toxin

heat-labile AB polypeptide lethal at 0.1 microgram per kilogram of body weight; extraordinary potency --> death by necrosis of the heart & liver; AB polypeptide is proteolytically processed; subunits connected by disulfide bridge.

diphtheria toxin (DT)

§ Antibiotic inactivation: enzymatic inactivation of antibiotic to confer drug resistance.

directly targeting antibiotic

applied to nonliving objects/surfaces (i.e., bleach, alcohols, & phenolics); § Primarily bactericidal; too toxic for use for external/internal treatment of patients.

disinfectants

biological agents (bacteria, viruses, or toxins) that are used in non-malicious ways (therapeutic development, & educational purposes) but could also be used as bioweapons (i.e., botulinum toxin, staphylococcal enterotoxins, B. anthracis, & many others).

dual-use agents

adenylate cyclase --> high levels of intracellular cAMP --> disturbance of H2O homeostasis, disruption of intracellular signaling pathways. § Net result: shock & lethality (precise mechanisms still under investigation).

edema factor

assembly of the T3SS: _____ are released from the chaperone & unfolded thru an ATP-driven process & secreted thru the needle by the PMF.

effectors

____ actively remove AMPs from cytoplasmic membrane. secreted proteases contribute to degrading _____.

efflux pumps; AMPs

P. aeruginosa virulence factor: proteolytic degradation of elastin, collagen, immunoglobulins, competent proteins, immune evasion, & nutrient acquisition; tissue damage.

elastase, alkaline protease, & other proteases

examples of S. aureus biofilm infections?

endocarditis, implanted medical devices, diabetic foot ulcers

survival strategies of pre-infection stages of Clostridium & Bacillus?

endospore formation

embedded in bacterial cell surface & released by cell lysis (i.e., LPS, teichoic acids).

endotoxins

toxins are not only proteins but also other molecules. non-protein toxins are _____, such as LPS, LTA, & PG.

endotoxins

type of protein exotoxin (type 2) that causes destabilization of membrane via destruction of host cell membrane lipids (various targets); phospholipase removes polar head group (stabilizes lipid bilayer); alpha-toxin from Clostridium perfringens -> wound infection (gangrene).

enzymatic toxins

extracellular transport of non-proteinaceous compounds.

excretion

S. pneumoniae: _____ remove sugar residues from host glycoproteins.§ E.g., neuraminidase NanA: nutrition; exposure of new sites on the host cell surface for binding; signal for 2-cpmponent regulatory systems à biofilm formation.

exoglycosidases

translocation of proteins from cytosol to periplasm (gram-negative).

export

iron acquisition in gram-positive bacteria: import of _____ driven by ATP hydrolysis thru coupling to the ATPase.

ferric-bound siderophores

i. Do not always function as adhesins. ii. For instance, bacterial M-protein thought to bind Fibronectin in S. pyogenes infection by M proteins also inhibit complement fixation, etc.

fimbria-like surface proteins:

travel between environments & chemotaxis; long (up to 20 micrometers) helical structures that extend outward from cell surface; polymerized subunits of flagellin protein; expression usually turned off in host; also regulated by phase variation ("on/off" control of gene expression, which allows for a response to rapidly changing environmental conditions).

flagella

_____ proteins are relatively conserved (i.e., recognition by TLR-5) & antigenic ("H" antigens of motile bacteria).

flagellin

P. aeruginosa virulence factor: motility, dissemination, initiation of the innate immune response.

flagellum (polar)

some receptors recognize siderophores of other bacteria; "_____."

freeloading

clustered regularly interspaced short palindromic repeats --> edit genome to study the function of genes, e.g., delete a gene or activation.

gene editing via CRISPR-Cas9

type of transgenic animal model in which a gene is replaced w/ gene from another animal, human, or replaced by mutant gene.

gene replacement mice

inhibit transglycosylation & transpeptidation steps in peptidoglycan synthesis by binding D-Ala-D-Ala. resistance mechanisms: gram-negative outer membrane alterations; modify target (substitute D-Ala-D-lactate for D-Ala-D-Ala). most effective against gram-positive bacteria.

glycopeptides

_____ use AHL bacterial QS systems for intraspecies communication.

gram-negative bacteria

binding of AHL to receptor regulatory protein within cell --> protein dimerization --> regulation of target genes.

gram-negative bacterial quorum sensing

o Many are human microbiota. o Take advantage of breaches (not random breaches!) of human defenses to cause infections that they would normally be unable to cause in the healthy individual. o Adapted to respond to a limited range of opportunities. o Antibiotic resistance is common.

gram-negative opportunistic infections

iron acquisition in _____ bacteria: bacterial membrane-anchored Fe-binding protein & membrane-associated ABC transporter system.

gram-positive

T7SS found in _____ & _____.

gram-positive bacteria & Mycobacteria

diphtheria: formation of _____ (necrotic host cells, fibrin, bacteria) over tonsils, pharynx, larynx --> removal causes bleeding; chunks of membrane can break off & cause asphyxiation.

grayish pseudo membrane

virulence factor production is often ______-dependent.

growth-phase

oxidizing agents

halides

bind -SH groups, thus denaturing proteins.

heavy metals (e.g., Hg2+, Ag+)

S. aureus can also scavenge iron-bound _____ & _____ thru a series of iron-regulated surface determinants (ISD) protein.

heme; hemoglobin

P. aeruginosa virulence factor: pore-forming toxins that damage host cell membranes.

hemolysins

membrane-disrupting toxins that lead to host cell lysis; roles include killing of host cells & escape from phagosome.

hemolysins & cytolysins

often used w/ mass spectrometry (MS).

high-performance liquid chromatography (HPLC)

what are some virulence factors?

i. Biofilm formation ii. Motility & chemotaxis iii. Production of siderophores iv. Iron abstinence v. Capsules (usually polysaccharides) vi. Lengthened & shortened LPS O antigen vii. sIgA proteases viii. C5a peptidase ix. Pili & fimbriae x. Nonfimbrial adhesion xi. Binding to M cells

bacterial mechanisms for resistance or deactivation of nitrogen?

i. Flavohemoprotein (Hmp) à NO to NO3- or N2O

function of IpaB?

i. Forms translocon pore in mammalian membrane w/ IpaC ii. IpaB/IpaC mediate uptake of coated beads

many bacteria have redundant iron acquisition systems. other strategies?

i. Iron abstinence (B. burgdorferi) ii. Hemolysins, cytolysins iii. Heme uptake systems (S. aureus) iv. Proteases that degrade lactoferrin, transferrin

bacterial mechanisms for resistance or deactivation of oxygen?

i. Superoxide dismutase --> O2- to H2O2 ii. Catalase --> H2O2 to H2O i. Membrane carotenoid pigments (numerous conjugated double bonds enable the detoxification of ROS).

how does Shigella invade the epithelium, and what are the other key players in the invasion and spread of Shigella?

i. secretes virulence factors via T3SS to get into epithelial cells. ii. replicates & forms actin tails to continue spreading. iii. produces effectors to downregulate inflammation & the innate immune response.

mycolactone

immunosuppressant & neurosuppressant; pro-apoptotic; located on plasmid; produced by Mycobacterium ulcerans.

DAMPs & PAMPs trigger _____ activation resulting in IL-1beta & IL-18 cytokine generation & secretion; _____ cleaves immature cytokines into mature forms.

inflammasome; caspase-1

· Fiery pyroptosis enhances _____.

inflammation

o Host response to S. pneumoniae (epithelial cells & alveolar macrophages): production of _____ (IL-1, TNF-alpha, IL-18, complement proteins, AMPs).

inflammatory mediators

genes needed for colonization (e.g., adhesins (attachment proteins) à promoter close associations w/ host cells.

initial lag phase

T3SS _____ seals off before the needle structure is assembled (not present in flagella).

injectisome

survival strategies of pre-infection stages of Legionella pneumophila?

intermediate host (e.g., insect, amoeba)

what are Ipa proteins?

invasion plasmid antigens i. encoded on virulence plasmid (ipaBCDA) ii. essential for virulence iii. highly immunogenic (convalescent monkey serum)

P. aeruginosa: cystic fibrosis (CF) airways characterized by inadequate _____ & defective mucociliary clearance --> predisposition to persistent microbial colonization.

ion transport

type of transgenic animal model in which a gene is introduced.

knock-in mice

type of transgenic animal model involves deletion of a gene or truncation/inactivation of a gene; includes gene-edited mice & conditional knockout mice.

knockout mice

used to extract specific/localized regions of interest from tissue.

laser capture microscopic dissection (LCM)

exotoxin of B. anthracis: zinc metalloprotease --> selectively inactivates mitogen-activated protein kinase kinases (MAPKKs) --> deregulation of numerous cell processes --> abnormal ion transport, loss of electrolytes & water, blockage of cellular signal transduction pathways, improper functioning of immune response. § Net result: shock & lethality (precise mechanisms still under investigation).

lethal factor

genes required for persistence (proteins required to withstand the immune response).

logarithmic/exponential phase

general characteristics of antibiotics? - _____ compounds that kill/inhibit bacterial growth. - can be ingested or injected into humans or animals w/ minimal side effects. - generally, interfere w/ a specific _____/_____.

low-medium MW; cellular process/enzyme

lux system - Vibrio fischeri: _____ generates blue-green light thru oxidation of reduced flavin mononucleotide (FMNH2) & long-chain fatty aldehyde (RCHO).

luciferase

lux system - Vibrio fischeri: _____ produced by LuxI binds to LuxR to positively regulate transcription of other lux genes.

lux operon AHL (AI-1)

bind 23S rRNA in 50S subunit of bacterial ribosome. resistance mechanisms: methylation of target; mutation in 23S rRNA genes; efflux. bacteriostatic for most; bactericidal for some gram-positive bacteria.

macrolides/lincosamides

methicillin resistance is encoded by _____ gene --> alternative penicillin-binding protein (PBP2a) resists beta-lactam antibiotics such as methicillin; ound on staphylococcal cassette chromosome (SCC) mec element. § Often associated w/ genetic resistance to other classes of antibiotics.

mecA

general strategies of pre-infection stages?

metabolic dormancy, attachment/growth on abiotic surfaces, genome plasticity, protection against secondary metabolites (acids, antibiotics, bacteriocins, antimicrobials peptides) that bacteria themselves produce (efflux pumps).

DNA inhibitor

metronidazole

these 2 are used to compare host gene expression changes in response to infection.

microarrays and RNA-seq

most bacteria have surface components (protein & carbohydrates) that are bound by _____; viscosity inhibits swimming motility; relatively resistant to enzymatic digestion.

mucin

- binding to multiple cell surface receptors (gangliosides, glycolipids). - preassembled at the point of expression - holotoxin complex enters host cells. - endocytosis followed by pH-dependent translocation of A subunit. ...or... - retrograde transport to ER followed by secretory transport to cytoplasm (via Golgi) or to nucleus (localization signal sequences). includes CT, PT, anthrax toxin

multi-subunit A-B toxins

§ Strands of repeating glycan units (N-acetylmuramic acid & N-acetylglucosamine) covalently linked by a beta-1,4 glycosidic bond. § Peptide: L-alanine, D-glutamate, 'X' (e.g., meso-DAP, L-alanine), & D-alanine.

murein

iron acquisition in gram-______ bacteria: iron uptake mechanism via transferrin/lactoferrin, siderophores, or heme; requirement of an outer membrane receptor, a periplasmic-binding protein, & an inner membrane ABC transporter system.

negative

- synthesized in cytosol & transported/stored in presynaptic vesicles at the nerve terminal. - membrane proteins in the presynaptic vesicle interact w/ a protein complex on the presynaptic plasma membrane. - vesicle docking & formation of the primed state.

neurotransmitter acetylcholine (Ach)

various S. epidermidis sensing domains recognize various signals (small molecules, peptides, ions, or stress conditions).

o 1. Stimulation --> intracellular domain of sensor histidine kinase undergoes autophosphorylation of specific histidine residues --> o 2. Cognate response regulator recognizes phosphoryl-histidine residue --> transfer of the phosphoryl group to a specific aspartate residue in the response regulator's receiver domain (phosphorylation) --> o 3. Conformational change in the protein's effector domain --> modulation of downstream cellular processes (e.g., via transcriptional activation or repression).

why are cell wall synthesis inhibitors good antimicrobial therapeutics?

o Cell wall as unique feature in bacteria. o Generally safe. o Peptidoglycan (murein) biosynthesis as a target. o Gram-positive bacteria more sensitive to such antibiotics targeting murein.

· Symptoms of MRSA Skin Infection?

o Infected area resembles a spider bite (bump/infected area); unless a spider is seen, the irritation is likely not a spider bite. o Red, swollen, painful, & warm to touch. o Full of pus or other drainage. o Accompanied by a fever. o Treatment: infection lanced/drained by physician, & an antibiotic is prescribed. o Important not to ignore symptoms; if MRSA escapes the abscess, serious systemic infection may occur.

· Lack of the Development of New Antibiotics?

o Limit on mechanisms o Short antibiotic lifespan (resistance in 8 years, 50 years lifespan). o Prolonged development period (10-20 years). o High cost: up to $2 billion o Unfavorable economics of drug development.

various functions of bacterial toxins as virulence factors and players in environmental fitness?

o Protection against macrophages, neutrophils. o Immunomodulatory function: effect on cell signaling to dampen immune response (e.g., cytokine production). o Release of carbon/iron stores. o Environmental fitness? (i.e., botulinum neurotoxin aka BoNT) o Toxin genes can be encoded by extra-chromosomal elements (lysogenized phage, plasmid, pathogenicity island) à HGT. o Toxin damage to human body may be an "accidental" side effect.

some other factors contributing to AMR?

o Weakened immune system increase changes of developing infection that will require antibiotic treatment. o The FDA banned used of antibiotic agents in personal hygiene products. Use of antibiotics in farm animals select for antibiotic-resistant bacteria. o Cross-contamination leads to human exposure, potentially leading to serious infections. o Misuse of drugs in humans & animals is accelerating the process. o Leads to longer hospital stays, higher medical costs, & increased mortality. o Combination of meat, vegetables, dairy, & other products.

o Microbial pathogens that usually do not cause disease in healthy people; causes disease when host defenses become compromised.

opportunistic pathogens

o Some _____ can infect individuals w/ no identifiable underlying health conditions or acquire virulence properties (e.g., Streptococcus pyogenes à "flesh-eating" bacteria).

opportunistic pathogens

o Subgroups of strains sharing the core genome/pangenome (80% genome) & 20% "accessory" genes (genomic islands, prophages, plasmids, or mobile genetic elements).

pangeome

type of individuals are affected by carbapenem-resistant Enterobacteriaceae?

patients in healthcare facilities, especially those who require devices (e.g., catheters) & those patients who take long courses of some antibiotics.

_____ are penicillin derivatives, and beta-lactams are 4-membered lactams. _____ is a penam, and penam is a time of beta-lactam antibiotic.

penams; Penicillin

naturally occurring antibiotic derive from mold; Egyptian doctors used moldy bread to treat wounds some 3,500 years ago.

penicillin

o Proteins found in bacteria. o Bind antibiotics of the beta-lactam class (e.g., penicillin). o Bind B-lactam antibiotics since structure of these antibiotics is like sugar-amino acid backbone. o Involved in the process of synthesizing cross-linked peptidoglycan (final stages of PG synthesis). o Upon binding w/ penicillin, B-lactam amide bond in _____ is ruptured --> penicillin forms a covalent bond w/ catalytic serine residue at the _____ active site. o Irreversible reaction inactivating the enzymes.

penicillin-binding proteins (PBPs)

Yersinia prevents _____, phagosome-lysosome fusion, & to host lymph nodes to replicate. Bacteria other than Yersiniae are phagocytosed into the cell inside a vesicle called the phagosome. The phagosome then fuses w/ lysosomes to enable proteolytic degradation of the bacterium of which the debris is then removed from the cell via exocytosis.

phagocytosis

escape from _____ causes growth in cytoplasm (nutrients, protection from antibodies, complement).

phagosome

denature proteins; disrupt cell membranes by intercalating in them.

phenols

P. aeruginosa virulence factor: hydrolysis of phospholipids in host membranes, tissue damage, phosphate acquisition.

phospholipases

rod-shaped chain of polymerized pilin protein subunits (~0.5-10 micrometers) that promoter tissue-specific interacts "tropism"; involved in pathogen adherence (i.e., over 30 types identified in E. coli).

pili (fimbriae)

tip of _____ = adhesin that attaches to host receptor.

pilus

where are virulence factors of Shigella located?

plasmid that contains operon that encodes T3SS responsible for bacterial entry.

plasminogen -> _____ -> degradation of fibrin clots (streptokinase serine protease).

plasmin

_____ activators are used in healthy cells for wound healing.

plasminogen

_____ surface proteins exhibit variability among different serotype strains.

pneumococcal

multiplication of _____, invasion of S. pneumoniae into bloodstream via platelet-activating factor receptor (PAFR), poly-Ig receptor (PIGR), & soluble CD14 (sCD14).

pneumococci

S. pneumoniae soluble, cytolytic toxin: § Binds to TLR4 à proinflammatory responses. § Assembled in the cholesterol-containing membranes of host cells. § Pore-forming § Activation of CD4+ T cells & chemotaxis of immune cells

pneumolysin

_____ (P. aeruginosa, V. cholerae, H. pylori) vs. _____ flagella (E. coli, S. enterica, Proteus mirabilis) or dual flagellar systems (Vibrio parahaemolyticus).

polar; lateral

function of B. anthracis capsule?

poly-y-D-glutamic acid polypeptide; protects against phagocytosis

Gram-_____ bacteria have a thick peptidoglycan layer and no outer lipid membrane whilst gram-_____ bacteria have a thin peptidoglycan layer and have an outer lipid membrane.

positive; negative

Normal Neurotransmission at Synapse of Neuromuscular Junctions: neurotransmitters bind to _____ receptors on muscle -> .muscle movement.

post-synaptic

one of the 2 major routes of the sec translocation system; SecB-mediated in E. coli & relatives, most common in bacteria; sec substrates exceed number of available translocation pores (lower abundance of Sec-pores in prokaryotes vs. eukaryotes).

post-translational

Secreted enzymes that degrade

proteases

single polypeptide that is cleaved during processing; A & B subunits still linked by disulfide bond, which is broken under reducing conditions of cytosol; A & B subunits interact by noncovalent interaction, which are disrupted when inside host cell.

protein exotoxin type 3

"exotoxins" (secreted) or "exoenzymes" (release via cell lysis, delivery via injection).

protein toxins

- used to characterize functional protein networks & their dynamic alteration during infection. - combination of high-resolution protein separation techniques w/ mass spectrometry & database mining tools.

proteomics

_____ provides energy for the rate-limiting step of the T3SS transport.

proton motive force (PMF)

P. aeruginosa virulence factor: small-molecule toxic blue-green pigment; redox-active compound that generates reactive oxygen species; disrupts action of cilia & phagocytic function.

pyocyanin

P. aeruginosa: § Large amounts of _____ produced in lungs of CF patients. § Interferes w/ normal redox cycle of mammalian cells. § Production of reactive forms of oxygen that damage the mammalian cell.

pyocyanin

implications of _____: § Pathogens can limit the host response while growing. § Pathogen detects when a host site has become saturated. § Coordinated expression of cell processes.

quorum sensing

population density-based method of intercellular bacterial communication.

quorum sensing

P. aeruginosa virulence factor: key role in controlling virulence factor production, biofilm formation, swarming motility, & expression of antibiotic efflux pumps.

quorum sensing - LasR (3-oxo-C12-HSL), RhlR (C4-HSL)

why can gram-positive opportunistic infections be particularly dangerous?

reach blood stream causing sepsis.

links regulatory circuit of a given virulence gene (vir) to a reporter gene.

reporter fusion

survival strategies of pre-infection stages of Staphylococci & Enterococci (important during dehydration)?

resistance to DNA damage/protein oxidation

RNA polymerase inhibitor

rifampin

Yersinia post-translational regulation of virulence: stringent response: amino acid starvation induces activation of _____ gene transcription & virulence.

rovA

some bacteria synthesize _____, which cleave hinge region, which creates separation of the part of the sIgA that binds bacteria from the part that interacts w/ mucin.

sIgA proteases

General Secretory Pathway (GSP) or _____ is found in the cytoplasmic membrane of all bacteria; chaperone proteins guide substrate complex, which transports them in an unfolded state from cytoplasm to the extracellular milieu in gram-positive bacteria or to the periplasm in gram-negative bacteria.

sec system

i. General secretory pathway for unfolded proteins ii. Proteins have N-terminal signal peptide, translocation apparatus SecYEG.

sec system

translocation of proteins from cytosol to extracellular milieu (environmental medium), other cells, or bacterial surfaces.

secretion

response of host to endotoxin of LPS; excess cytokine production & no release.

septic shock

how do bacteria prevent phagolysosomal fusion, including the mechanisms of Legionella pneumophilia, Salmonella typhimurim, and Mycobacterium tuberculosis?

sequestration of bacteria in specialized vacuoles within cytosol.

inhibit protein synthesis within target cells by a mechanism like that of the infamous plant toxin ricin.

shiga toxins

P. aeruginosa virulence factor: iron acquisition.

siderophores

i. Low MW, high affinity iron chelator. ii. Catechols & hydroxymates iii. Form tight iron-chelated complexes w/ high affinity iv. 10-18-10-9 M free iron concentration in human body

siderophores

Sec Post-translational System: i. SecA binds to _____ of the secretion substrate protein & _____ in inner membrane. ii. SecA undergoes an _____ conformational change driving translocation thru the pore of the translocase. iii. _____ helps the translated proteins remain unfolded before being delivered to the SecA-SecYEG complex. iv. _____ helps stabilize this process. v. _____ protein cleaves signal sequence from the protein --> protein is folded upon delivery to the periplasm. vi. Some proteins remain in the periplasm, while others will be secreted by transport across _____ (Type II & Type V secretion systems).

signal peptide (SP); SecYEG translocase (Channel); ATP-dependent; Chaperone SecB; SecDF-YajC; protease; outer membrane

DT, BoNTs; binding to cell surface receptors (protein, glycoprotein); endocytosis followed by pH-dependent translocation of A subunit.

single-chain A-B toxins

both _____ from wastewater & _____ are used as fertilizer carrying antibiotics & antibiotic-resistant bacteria onto commercial crops.

sludge; manure

naïve population; extremely contagious & lethal; has been used as a bioweapon in the past; ability to vaccinate exposed persons key in control of disease spread (disease prevented if vaccination occurs within 3-4 days post-exposure).

smallpox (virus)

after 2001 anthrax outbreak in USA: - Important for there to be an official organized network of scientific experts to communicate w/ media & the public. - Minimize hype & propagation of misinformation (i.e., needles destruction of anthrax strains at ISU). - Appreciation that a bioweapon attack does not have to be "a large-scale exposure w/ catastrophic outcomes" (pre-2001 era scenario). - Increased security, reporting requirement for obtaining & working w/ select agents. - Better medical infrastructure & crisis management plans now in place: - In 2002, decision made to acquire enough _____ for the entire U.S. population.

smallpox vaccine

iron acquisition in gram-positive bacteria: S. aureus has 2 iron-binding siderophores, ______ recognized by surface receptors, & heterodimeric permeases.

staphyloferrin A & B

_____ (protease that dissolves blood clots), hyaluronidase, V8 protease (cleaves human IgG), & exfoliative toxins (cause scaled-skin syndrome, characterized by blistering & peeling of skin).

staphylokinase

_____ acts as a plasminogen activator & cleaves plasminogen into plasmid, which then degrades fibrin clots & allows bacteria to escape from blood clots.

staphylokinase serine protease

after logarithmic/exponential phase, a transition to early _____ phase?

stationary

genes encoding toxins & degradative enzymes (spread thru the body).

stationary phase

o 1930s: introduction of _____ antimicrobials to treat gonorrhea. o 1940s: due to increasing resistance, sulfonamides no longer recommended for gonorrhea treatment; _____ becomes treatment of choice.

sulfonamide; penicillin

facilitate "unnatural associations" between CD4+ T cells & APCs; results in overstimulation of T cells à IL-2 à T & B cell proliferation/stimulation à toxic shock; Toxic Shock Syndrome (TSST-I) & enterotoxins (S. aureus), various Streptococcal SAgs.

superantigens

zones of growth inhibition around the discs/strips containing the antibiotic

susceptibility

§ Antibiotic target modification: mutational alteration or enzymatic modification of antibiotic target. § Antibiotic target replacement: replacement or substitution of antibiotic action target. § Antibiotic target protection: protection of antibiotic action target from antibiotic-binding.

target modification

§ Antibiotic efflux: transport of antibiotic outside of cell. § Reduced permeability to antibiotics: generally thru reduced production or modification of porins. § Resistance by absence: deletion of a gene (usually a porin).

targeting antibiotic availability

i. Translocates folded proteins ii. Protein have twin - arginine motif (Twin arginine translocation = Tat).

tat system

Yersinia post-translational regulation of virulence: _____ dictates ability of DNA-binding protein H-NS to bind & inhibit rovA expression.

temperature

_____ & _____ regulate the sporulation & germination of B. anthracis.

temperature; oxygen/CO2

receptor molecules interact w/ signaling proteins to form stable _____ complexes.

ternary

bind 16S RRNA in 30S subunit of bacterial ribosome. resistance mechanisms: inactivation of antibiotic; ribosome protection; mutation in 16S rRNA genes; efflux. broadly bacteriostatic; some protozoa.

tetracyclines

V. fischeri has 2 AHL quorum-sensing systems: - _____ - _____ o These systems work together in a sequential manner to regulate motility, colonization, & bioluminescence. o High-cell densities: reduced biofilm formation & increased virulence factor expression.

the hybrid AinSR system; the LuxIR system

o large macromolecules taken up into cells thru endocytosis, transported in vesicles thru the cell, & deposited on the opposite side of the cell. § S. pneumoniae binds to the poly-Ig receptor when exposed on the apical side of the cell, transcytosed to the basal side of the epithelial layer.

transcytosis

trafficking proteins from cytosol thru cell membrane.

translocation

beta-lactamases are _____ inhibitors.

transpeptidase

beta-lactams such as penicillin inhibit _____ in the peptidoglycan synthesis.

transpeptidation

segment of bacterial DNA that can be translocated between chromosomal, phage, & plasmid DNA in absence of a complementary sequence in host DNA; contain inverted repeats at their ends; encode enzymes required for transposition; often carry ABR genes; can be used as molecular tool for whole-genome & single-gene studies in bacteria.

transposons

active immunization in childhood prevents diphtheria, t/f?

true

antibiotic resistance is developed by bacteria, not humans which happens due to the high selective pressure. t/f?

true

channel that spans the periplasmic space & outer membrane are different between flagella & T3SS. t/f?

true

o Bacteria or antibiotics from humans & pet animals enter water systems thru ground & wastewater. t/f?

true

o Excretions from animal farms enter wastewater & are used as manure. t/f?

true

staphylococcus biofilms are inherently more recalcitrant to antibiotic treatment & the immune system. t/f?

true

protein exotoxins are _____ or ____ toxins.

type 2, type 3

long, amyloid-like coiled structures. ii. S. Typhimurium iii. Contribute to aggregation, microcolony formation, &/or biofilm formation.

type 5 pili (curli pili)

P. aeruginosa virulence factor: adherence, twitching motility.

type IV pili (polar)

gram-negative bacteria have _____ & _____ secretion systems; gram-positive have _____, injectosomes, _____, & sortase.

type-1; type-6; type-7; SecA2

· Factors Contributing to AMR in Healthcare?

underuse: not finishing prescribed antibiotics; use: increase risk for other infections (i.e., C. difficile); overuse: estimated that 25-75% prescriptions are not necessary. · Wrong dose · Wrong antibiotic - Lack of antibiotics - Poor sanitation & personal hygiene - Use of antibiotics in agriculture - Inadequate infection controls in healthcare facilities.

estimated that 10-90% of antibiotics are excreted in _____ & _____ leading to constantly increasing concentration of antibiotics in aquatic environments.

urine; feces

advantage of chemical/UV mutagensis?

useful if pathogen difficult to manipulate genetically.

substrates for sec system?

various surface & secreted proteins

substrates for TAT system?

various surface & secreted proteins; often fully folded & sometimes as multiprotein complexes

molecules produced or strategies used by disease causing bacteria that enable them to infect & survive in host.

virulence factors

nuclear, radiological, chemical, biological, or other device that is intended to harm many people

weapon of mass destruction

S. epidermidis protection against osmolarity change:

§ 8 sodium ion/proton pumps. § 6 transport systems for osmoprotectants.

several forms of disease of B. anthracis?

§ Cutaneous (most common; about 95% of reported cases) § Inhalation § Gastrointestinal § Injectional (drug use) (2009-2010 outbreaks in UK & Germany - 54 cases, 18 deaths).

examples of gram-negative opportunistic infections?

§ E. coli § Bacteroides fragilis § Klebsiella pneumoniae § Porphyromonas gingivalis § Pseudomonas aeruginosa § Burkholderia cenocepacia § Acinetobacter baumannii

what are the ESKAPE pathogens?

§ Enterococcus faecium § Staphylococcus aureus § Klebsiella pneumoniae § Acinetobacter baumannii § Pseudomonas aeruginosa Enterobacter species

S. epidermidis sensor histidine kinase: homodimeric transmembrane proteins:

§ Extracellular sensing domain § Intracellular histidine phosphotransfer domain

signals for translocation in T3SS (injectisomes):

§ Host membrane contact § Absence of Ca2+ levels & 37 degrees C in Yersinia. § O2 levels in Shigella § Local pH changes in Salmonella SPI-2.

o 2 different ways of action for type 2 toxins?

§ Killing of host cells to release cellular content for nutrient &/or metal acquisition, evasion of immune cell recognition. § Membrane-disrupting toxins used to escape from the phagosome & enter the cytoplasm before phagolysosomal fusion occurs.

all opportunistic infections caused by gram-negative bacteria?

§ S. aureus § S. epidermidis § Streptococcus pneumoniae § C. difficile § Streptococcus agalactiae (Group B strep) § Streptococcus pyogenes (Group A strep) § Enterococcus faecium

o Emerged shortly after introduction of methicillin (2nd generation penicillin) in clinical setting (1960 à 1961)

· MRSA: Methicillin-resistant S. aureus