Microbio (Boards)
5 years from now a new flu virus emerges. Scientists link it to birds, what is most likely to be the cause?
influenza A
prophage
integrated viral DNA
predominant bacteria on mucous memb of oral cavity
lactic acid bacteria + streptococci
Which of the following cell types produce IL-1?
macrophages
Rhinoviruses
main cause of common cold (no vaccine)
Influenza C
mild upper resp tract illness
Antigenic drift
minor changes caused by small genetic mutations (point mutations
negatie polarity (complimentary to mRNA)
must transcribe their own mRNA using negative strand as template
in addition to peptidoglycan, acid-fast cell wall of Mycobacterium contains large amt of glycolipids, esp ______ that make up 60% of acid-fast cell wall
mycolic acids
adenovirus
naked (nonenveloped) icosahedral nucleocapside + ds linear DNA genome
paramyxoviruses
negative sense ssRNA enveloped RNA-dependent RNA polymerase resembles orthomyxoviruses except they are larger, diff surface proteins, nonsegmented genomes
PicoRNAviruses
nonelnveloped ss positive sense RNA genome incapable of causing cell transformation
negative polarity or contain negative-sense RNA
orthomyxoviruses paramyxoviruses rhabdoviruses
bacteriophage w/ ability to form stable, nondisruptive relationship w/in bacetrium
temperate phage vs. virulent phage (lyses & kills host)
infarction causes
thrombosis obstruction from embolus/plaque aneurysm mechanical compression from tumor/hernia vessel rupture
The act of rough pneumococci, grown in the presence of DNA from dead smooth pneumococci, developing capsules is an example of
transformation (Genetic exchange b/w strains of bateria by transfer or incorporation of free DNA from another ruptured bacterial cell)
HSV-1
trigeminal ganglia oral secretions child under 10yo
Human adenoviruses are unlikely to target CNS b/c adenoviruses prefer epithelial cells for replication
true & related
RNA viruses
tx in cytoplasm (except for retroviruses + influenza viruses) tx involve sRNA-dependent RNA polymerase (except retroviruses)
DNA viruses
tx in nucleus (except for poxviruses) tx involves host-cell DNA-dependent RNA polymerase
widespread rash on trunk + face of child. mother states child has received vaccinia vaccine. child most likely infected w/
varicella-zoster virus 90% cases occur in children under 9yo. vesicles in skin -> disseminate ->become encrusted & fall off in 1wk administration of aspirin = CONTRAINDICATED (may increase incidence of REYE syndrome - encephalitis, liver impairment)
herpes virus infection that can be treated prophylatically by vaccine
varicella-zoster virus varicella - chickenpox herpes zoster - shingles attenuated varicella vaccine
DNA enveloped viruses
variola (smallpox) virus Hep B virus Epstein-barr virus NOT adenovirus
High fever (101-102F) that begins suddenly, muscle/bodyaches, chills, tiredness, sudden onset
Influenza
essential to f(x) of outer memb of gram-neg bacteria
LPS
Detection of protein A
Stphylococcus Aureus
T lymphocytes
CMV (cytomegalovirus) congenital infection (if mother becomes infected) infection in immunocompromised
Steps in replicative cycle of viruses
1) Attachment (receptor) 2) Entry (receptor-mediated endocytosis/membrane f(x)) 3) Uncoating (triggered by pH changes in endosomes) 4) Replication + viral protein production -all DNA viruses (except poxviruses) rep in nucleus using host cell RNA polymerase -all RNA viruses (except retroviruses, orthomyxoviruses) replicate in cytoplasm using their own RNA polymerase) 5) Assembly (new virus particles) 6) Release (budding thru host plasma memb or plasma memb ruptuer)
virus
1) Retroviruses contain RNA genome & reverse transcriptase 2) false - provirus = formed as viral RNA is directly incorporated into host DNA
bacteria
1) lancefield groups are based on antigenic characteristics of a cell wall carb called C substance 2)main pathogenic Lancefield groups for humans are A, B, C, D, G Group A (S. pyogenes), Group B (S. agalactiae)
Measles
1) paramyxovirus 2) resp droplets 3) ssRNA
4 characteristic phases of population growth of bacteria
1. Lag phase (cells are metabolically active but not dividing; resynthesis of EZs, coEZs, etc necessary for growth) 2. Log (logarithmic or exponential) phase (fastest growth period) 3. Maximum stationary phase (medium is being depleted in some nutrients) 4. Decline (Death phase)
Retroviruses
2 identical, ss +-sense RNA molecules RNA dependent DNA polymerase (reverse transcriptase)
nucleocapsid of HIV
2 ssRNA, reverse transcriptase, protease, integrase env gene (GP 120, GP41) pol gene gag gene (core proteins)
bacterial virus
Bacteriophage
Type 2
Cytotoxic, IgM or IgG, complement
Type 4
Delayed, CD4 + CD8, CD8 dominates
resting memory B lymphocytes
EB (Epstein Barr virus) primary: infectious mononucleosis secondary: Burkitt's lymphoma, B cell lymphoma, hairy leukoplakia, nasopharyngeal carcinoma
Sympathetic stimulation has an effect on carbohydrate metabolism because
Epi increases liver glycogenolysis
endotoxins = part of outer memb of cell wall of (lipopolysaccharides - LPS) LPS activates complement
Gram negative bacteria only
Staphylococcus aureus
Gram-positive Coagulase positive Causes infective endocarditis Possesses Surface protein A causes toxic shock syndrome hyaluronidase Catalase-positive Scalded skin syndrome
Lentiviruses
HIV 1 (AIDS) HIV 2 (AIDS)
virus
HSV type 2 mainly spreads by sexual contact can be spread from mother to infant during childbirth
trigeminal ganglion
HSV-1 primary: gingivostomatitis secondary: cold sore, keratitis, encephalitis
sacral gangli
HSV-2 genital herpes
Oncovirus
HTLV-1 (adult T-cell leukemia) HTLV-2 (myelopathy)
Influenza viruses = Orthomyxoviruses A + B most common in humans
Hemagglutinin (attachment) Neuraminidase (release) Negative-sense Lipoprotein coat Segmented Genome (Antigenic Shift - reassortment of genome pieces) negative sense ssRNA (Segmented) NOT ssDNA
cell w/in which a virus replicates
Host cell
Type 3
Immune Complex, IgG, complement
integration into host genome w/o killing host
Lysogenic cycle
viral multiplication w/in a host cell leading to destruction
Lytic cycle
Streptococcus pyogenes
M protein hyaluronidase rapidly destroys tissue
skin rash w/ Koplik spots
Measles (Rubeola)
painful swelling of parotid glands
Mumps
influenza C
NOT annual flu ONLY humans least severe ONLY antigenic drift
Inflammation of pharynx
Pharyngitis
virus
Retroviruses = RNA viruses that have genome surrounded by inner protein envelop & outer envelop that contains lipid & glycoprotein spikes, which serve to attach virus to host cells "retro" refers to possession of EZ reverse transcriptase (RNA-directed DNA polymerase), which tx's RNA to DNA during process of viral nucleic acid synthe
Flu-like symptoms & lymphadenopathy followed by rash on entire body
Rubella
crosses placenta TORCH - Toxoplasmosis, Others (syphilis, varicella, mumps, parvovirus, HIV), Rubella, CMV, Herpes Simplex
Rubella Herpes HIV Cytomegalovirus NOT measles
HSV-2
Sacral Ganglia sexual means (genitals)
produces hyaluroniase
Staph aureus Strep pyogenes Clostridium Perfrigens NOT Bordetella pertussis
Which family comprises 2 genera: Rubiviruses (rubella virus) + Alphaviruses (artrhopod-borne viruses)
Togavirus family
transfer of DNA from donor cell to recipient cell w/ DNA packaged w/in bacteriophage
Transduction
dorsal root + cranial nerve ganglia
VZV (varicella-zoster) primary: chickenpox secondary: singles
Antigenic shift
abrupt major change to virus by combining 2/more viruses to create mix of surface antigens
Mycobacterium species, along w/ members of a related genus Nocardia = classified as
acid-fast bacteria
What type of hypersensitivity reaction is mediated by IgE?
anaphylactic
Type 1 hypersensitivity
anaphylactic, IgE, IgG
influenza B
annual flu affects only humans not likely to change or pandemic ONLY antigenic drift
influenza A
annual flu infect animals (birds) + humans antigenic shift & drift -> rapidly changes & creates potential for pandemic
positive polarity (same as mRNA)
can use their RNA genome directly as mRNA
cariogenicity of S. mutans = ability to adhere to tooth surface. Attachment = largely due to presence of extracellular glycocalyx =
capsule protects cells against phagocytosis by eukaryotic cells mediates adherence identification purposes antiphagocytic polysach capsules
Congenital Rubella syndrome
cataracts heart defects deafness
Which of the following maintains a continuous antimicrobial effect (substantivity)?
chlorohexidine gluconate (12hr)
other staphylococci
coagulase negative
Amantadine
drug most commonly used to treat influenza
Herpresviruses
dsDNA nuclear membrane icosahedral nucleocapsid enveloped only viruses to obtain virion envelops by budding from host nuclear or Golgi membrane, not host plasma membrane
vaccinia vaccine
eliminated smallpox
Endotoxin
gram - LPS high potency low specificity not secreted; cell must due & lyse to release
Exotoxin
gram - and + protein extracellular high potency high specificity
members of Picornaviridae
hepaDNAvirus
ludwig's angina
infection of oral cavity infection of 3rd mand molar escapes oral cavity & fills submandibular + submental triangles migrating swelling can compress airway can be fatal w/o dental care
Epstein-barr virus = causative agent for all
infectious mononucleosis nasopharngeal carcinoma Burkitt lymphoma oral hairy leukoplakia
phage T4
infects E.coli
Influenza A
pandemics + epidemics
acid-fast wall components
peptidoglycan (prevents osmotic lysis) mycolic acids (impede entry of chemicals) surface proteins periplasm (contains EZs for nutrient breakdown)
largest & most complex DNA virus family
poxvirus family largest & most complex viruses known
virus
prions = generally quite resistant to proteases, heat, radiation, formalin treatments, altho their infectivity can be reduced by such treatments prion dx's = usually rapidly progressive & always fatal
Which of the following is true of Streptococcus pyogenes?
releases endotoxins (attach to host tissues, evade immune response, spread by penetrating host tissue layers) human pathogen causes strep throat, scarlet fever, impetigo, rheumatic fever, form of glomerulonephritis, mitral valve affected Scarlet fever = antibodies produced to fight S. pyogenes cross rxt w/ host heart tissue group of A beta-hemolytic, gram + streptococcus
paramyxovirus that causes many resp infection epidemics each winter. common cause of bronchiolitis in infants, complicated by pneumonia in approx. 10% of causes
resp syncytial virus (RSV) lacks envelop glycoproteins covered w/ spikes no vaccine or antibiotics available antigenic drift
positive sense RNA/ positive polairity
retroviruses
virus
rotaviruses = most common cause of gastroenteritis in children reoviruses have icosahedral capsid composed of outer + inner protein shell containing double-stranded segmented genome (nonenveloped)
capsules
s. mutans Klebsiella pneumoniae Cryptococcus neoformans
poliovirus (enteroviruses, rhinoviruses, hep A)
salk vaccine (killed-IV) sabin vaccine (live,attenuated-orally) picornaviridiae
Influenza B
smaller/localized outbreaks (camps, schools)
Orthomyxoviruses + Paramyxoviruses share
ssRNA enveloped negative-sense NOT segmented (only orthomyxoviruses)
In which muscular triangle of the neck will you initially find swelling in a Ludwig's angina clinical case?
submental + submandibular triangles
Adenosine arabinoside (vidarabine)
suppresses synthe of varicella-zoster & HSV tends to diminish new lesion formation & duration of fever prevents spread of virus thru viscera
lysogenic bacteirum
temperate bacteriophage