Microbiology

When to use Ziehl-Neelson (carbol fuchsin, Fite stain)

Acid-fast bacteria (Nocardia, Mycobacteria) Protazoa (Cryptosporidium) When screening use auramine-rhodamine stain -- less expensive, more sensitive but less specific

Branching Filamentous (Gram Pos)

Actinomyces Nocardia (weak acid fast)

Pigment producing Bacteria

Actinomyces israelii - yellow "sulfur" granules made of filaments of bacteria S. aureus - yellow Pseudomonas aeruginosa - blue-green Serratia marcescens - red

Pseudomonas aeruginosa

Aerobic, motile, gram negative rod. Oxidase+, nonlactose fermenting. Produces pyocyanin (blue-green pigment). Smells like grapes. Causes pneumonia, sepsis, otitis externa, osteomyelitis, ecthyma gangrenosum, folliculitis (hot tub). Toxins: endotoxin, Exotoxin A. Think PSEUDDO: Pneumonia Sepsis Otitis Externa UTI Drug use Diabetes Osteomyelitis In burn victims watch out for wound infections. May be source of chronic pneumonia in CF patients (due to biofilm formation) Tx depends on source, severity and sensitivity.

Lengionella pneumophila

Aerosol transmission from water reservoir (eg. air conditioner). No person-to-person transmission. Causes legionnaires' disease (severe pneumonia, fever, GI and CNS symptoms) and Pontiace fever (mild flu like illness). Gram negative rod -- poor staining, use silver stain. Grow on charcoal yeast extract culture with cysteine and iron. (French legionnaire with a silver helmet, sitting around a campfire [charcoal] with his iron dagger -- he's no sissy [cysteine]) Pt. may be hyponatremic on labs Tx: macrolide or quinolone.

Haemophilus influenza

Aerosol transmission. Many strains, but nontypeable strains most common cause of mucosal infectins (otitis media, conjunctivitis, bronchitis). Since HiB vaccine introduced, nontypable strains also most common cause of invasive infections. Causes Epiglottitis, Meningitis, Otitis media and pneumonia (haEMOPholis). Small gram negative coccobacilli. Culture on chocolate agar with factors V and X (grow with S. aureus which lyses RBC and provides factor V). Produce IgA protease. T: amoxicillin (± clavulanate) for mucosal infections. Meningitis treated with ceftriaxone. Rifampin prophy for close contacts.

Pulmonary Anthrax

Flu-like symptoms that rapidly progress to fever, pulmonary hemorrhage, mediastinitis and shock

Gram Positive Rods

Bacillus Clostridium Crynebacterium Gardnerella (gram varies) Lacobacillus Mycobacterium (acid fast) Propionibacerium

Transformation

Bacteria picks up naked DNA from environment. Think SHiN (S. pneumo, HiB, Neisseria)

Gram Negative Rods (Enterics)

Bacteroides Campylobacter E. coli Enterobacter Helicobacter Klebsiella Proteus Pseudomonas Salmonella Serratia Shigella Vibrio Yersinia

Gram Negative Rods (Zoonotic)

Bartonella Brucella Francisella Pasteurella

Lancefield Grouping of Strep. spp.

Based on differences in C carbohydrate on bacterial cell wall.

How do I culture B. pertussis?

Bordet-Gengou agar: Potato Regan-Lowe medium: Charcoal, blood, antibiotic

Gram Negative Rods (Respiratory)

Bordetella Haemophilus (pleomorphic) Legionella (silver stain)

Urease-positive organisms

CHuck Norris hates PUNKSS Cryptococcus H. pylori Proteus Ureaplasma Nocardia Kelbsiella Staph. epidermidis Staph. saprophyticus

Encapsulated Bacteria and Immunology

Capsule is virulence factor -- protects microbe from phagocytosis Vaccine made from capsule + conjugated protein Capsule opsonized then clears in spleen, so asplenic patients have increased risk of severe infections and must be given Strep pneumo, HiB and meningococcal vaccines.

Catalase-positive organism

Cats Need PLACESS to hide Catalase + Nocardia Pseudomonas Listeria Aspergillus Candida E. Coli Staphylococci Serratia

Secondary TB

Caused by reactivation of latent TB in any organ or reinfection in partially immune (but hypersensitized) host Pulmonary TB: Fibrocaseous cavitary lesion, often in upper lobes Extra-pulmonary TB: CNS: Parenchymal tuberculoma or meningitis Vertebral body: Pott disease Lymphadenitis, Renal, GI or Adrenal infection

Corynebacterium diphtheriae

Causes diphtheria when it produces diphtheria toxin (encoded by β-prophage). Symptoms include pseudomemranous pharyngitis, lymphadenopathy, myocarditis, arrythmia. Toxoid vaccine prevents diphtheria. Gram positive rods with metachromatic (blue and red) granules. Forms black colonies on cystein-tellurite agar. Test for toxin with Elek test. ABCDEFG ADP-rybosylation β-prophage Corynebacterium Diphtheriae Elongation Factor 2 Granules

Strep pyogenes (GABHS)

Causes: Pyogenic -- pharyngitis, cellulitis, impetigo, erysipelas Toxigenic -- scarlet fever, toxic shock-like syndrome, necrotizing fasciitis Immunologic -- rheumatic fever (Anti-M protein), acute glomerulonephritis (immune complex deposition) Acute Rheumatic fever: Polyarthritic, carditis, nodules, erythema marginatum, sydenham chorea Scarlet fever: scarlet, sand-papery rash, strawberry tongue, circumoral pallor, subsequent desquamation Glomerulonephritis follows impetigo more often than pharyngitis β-hemolytic gram positive cocci in pairs and chains. Bacitracin sensitive. ASO titer detects recent infection.

Staphylococcus aureus

Causes: skin infections, abscesses, pneumonia (s/p influenza), endocarditis, septic arthritis, osteomyelitis, toxic shock syndrome (tampons or nasal packing), food poisoning (enterotoxin is heat stable, even cooked food can cause symptoms). Gram positive cocci in clusters. Catalase+ and coagulase +. Normal flora of nares.

When to use Giemsa Stain

Certain Bugs Really Try Patience Chlamydia Borrellia Rickettsia Trypanosomes Plasmodium

How do I culture Legionella?

Charcoal yeast extract agar buffered with cysteine and iron

Listeria monocytogenes

Children and adults: acquired by ingestion of unpasteurized dairy products and cold deli meats. Otherwise healthy patients -- mild gastroenteritis Immunocompromised patients -- meningitis Pregnant women -- amnionitis, septicemia, and spontaneous abortion Fetus: acquired by transplacental transmission. Causes granulomatosis infatiseptica (premature birth/spontaneous abortion due to fetal sepsis) Neonates: acquired by vaginal transmission during birth. Causes meningitis Facultative intracellular microbe that spreads from cell to cell via actin polymerization (seen as "rocket tails" on microscopy), thus avoiding antibody. Only gram positive organism that produces endotoxin Treat with ampicillin in infants, elderly or immunocompromised patients as empiric treatment for meningitis

Pleomorphic (Geimsa)

Chlamydiea Rickettsiae

How do I culture H. flu?

Chocolate agar: Factor V (NAD+) and Factor X (hematin)

Spore

Coat made of Keratin-like coat; dipicolinic acid; peptidoglycan

When to use India Ink

Cryptococcus neoformans

Transduction (Generalized)

During packaging of products of lytic bacterophage, bacterial DNA may be incorporated into viral capsid. When next bacteria is infected, these genes are transferred.

Endotoxin effects

ENDOTOXIN Edema (cause by compliment activation -- C3a) Nitric oxide (released by macrophages, leads to hypotension) DIC/Death (caused by tissue factor activation) Outer membrane TNF-α (released by macrophages, leads to fever and hypotension) O-antigen Xtemely heat stable IL-1 (released by macrophages, leads to fever) Neutrophil chemotaxis (mediated by complement activation -- C5a)

How do I culture M. pneumoniae?

Eaton agar: requires cholesterol

How do I culture E. coli?

Eosin-methylene blue (EMB) agar: colonies with green metallic sheen

M protein

Expressed by Group A Strep. (S. pyogenes) Helps prevent phagocytosis Has molecular mimicry (shares similar epitopes) to human cellular proteins. May underlie rheumatic fever autoimmune response.

Protein A

Expressed by S. aureus. Binds Fc region of IgG, preventing opsinozation and phagocytosis.

Conjugation

F+ (has a pilus) bacteria contacts F- bacteria (no pilus) and transfers a plasmid along the pilus. No transfer of chromosomal DNA

Nocardia

Found in soil. Causes pulmonary infection in immunocompromised patients, and post-tramatic cutaneous infection in immunocompetent patients. Gram positive aerobe that forms filaments (looks like fungi). Requires acid fast stain. Treat with sulfonamides. When you have filamentous bacteria, treatment is a SNAP (Sulfonamides for Nocardia, Actinomyces get Penicillin)

Anaerobes

Frankly Can't Breath Air Fusobacterium Clostridium Bacteroides Actinomyces Have no catalase or superoxide dismutase and undergo oxidative damage. Foul smelling (short fatty acids), difficult to culture, produce gas (H2 and CO2) in tissue. Normal GI flora, but pathogenic when elsewhere Aminoglycocides are inneffective b/c require O2 for transport into cell

When to use Silver stain

Fungi Legionella Helicobacter pylori

Klebsiella

GI flora. Causes lobar pneumonia when apsirated (alcoholics and diabetics). Causes "currant jelly" sputum -- very muccoid colonies from abundant polysaccharide capsule. Can cause nosocomial UTI 4 A's of Klebsiella Aspiration pneumonia Abscess in lung or liver Alcoholic diAbetic

E. coli

GI flora. Multiple virulence factors allow for pathogenicity in various settings: fimbriae -- cystitis, pyelonephritis; K capsule -- pneumonia, neonatal meningitis; LPS -- sepsis Four GI pathogenic strains: EPEC: No toxin. Adheres to apical sruface, flattening villi, preventing absorption. Diarrhea in children (EPEC -- Pediatric) ETEC: Heat labile and heat stabile enterotoxins. No inflammation or invasion. Causes watery diarrhea (ETEC -- Traveler's diarrhea) EIEC: Invades intestinal mucosa causing necrosis and inflammation, leading to dysentary (clinical manifestation like shigella). (EIEC -- Invasive) EHEC (STEC): Produces shiga-like toxin. Causes dysentery (toxin causes necrosis and inflammation) and HUS (anemia [w/ schistocytes], thrombocytopenia and AKI). Most common serotype 0157:H7. Unlike other E coli, does not ferment sorbitol.

Transposition

Genes move within chromosome or from chromosome to plasmid (or vice versa). When transposition occurs, flanking DNA may move to plasmid

Primary TB

Ghon Complex: 1. Ghon focus in lower to mid zone of lungs 2. Lymphadenopathy of hilar nodes. Symptoms: fever, night sweats, weight loss, cough (±productive), hemoptysis Four possible outcomes 1. Heals by fibrosis -> immunity and hypersensitivity -> Tuberculin+ 2. Progressive lung disease (pts. with HIV, malnutrition) -> death (rare) 3. Severe bacteremia -> miliary TB -> death 4. Preallergic lymphatic or hematogenous dissemination -> dormant TB in multiple organs -> reactivation in later life

ADP ribosylating A-B toxin

Group of toxins with two components. B (binding) component binds host cell surface receptor, enabling endocytosis. A (active) component attaches ADP-rybosyl to disrupt host cell target proteins

Hfr

High frequency recombination: plasmid incorporated into chromosomal DNA. When replicated, plasmid may now contain some flanking chromosomal DNA, which may then be transferred by conjugation.

Strep agalactiae (GBS)

Normal vaginal flora. Causes pneumonia, meningitis and sepsis in neonates. Produces CAMP factor, which enlarges area of S. aureus hemolysis. Test pregnant women at 35-37 weeks, prophylax women with positive culture (penicillin). β-hemolitic gram positive cocci in pairs and chains. Bacitracin resistant. Hippurate test+.

Identifying Staph spp

Novobiocin - Saprophiticus is resistant, Epidermidis is sensitive (NO StRESs)

Spiral/Spiriochetes (Gram Neg)

Leptospira Treponema Borrelia (Giemsa)

How do I culture M. tuberculosis?

Lowenstein-Jensen agar

Transduction (specialized)

Lysogenic phage DNA is incorporated into bacterial chromosome When phage DNA is excised, flanking bacterial DNA comes with and is incorporated into viral capsid and transferred to next bacterial host. Think ABCDE ShigA-like toxin Botulinum toxin (certain strains) Cholera toxin Diphtheria toxin Erythrogenic toxin of S. pyogenes

Mycobacteria

M. Tuberculosis: TB, often multi-drug resistant M. avium-intercellulare: disseminated disease in AIDS pts. Often multi-drug resistant. Prophylax with azithromycin when CD4+ counts <50 M. scrofulaceaum: cervical lymphadenitis in children M. marinum: hand infection in aquirium handlers Cord factor in virulent strains inhibits macrophage maturation and induces release of TNF-α. Sulfatides (surface glycolipids) inhibit phagolysosomal fusion.

Leprosy

M. leprae. Acid fast bacillus that prefers cool tempratures (infects skin and superficial nerves). Cannot be grown in vitro! Reservoir in US is armadillos. Lepromatous disease: Present diffusely over skin, but glove and stocking pattern of spread. Leonine (line like face). Low cell mediated immunity with humoral Th2 response. Is communicable. Most common cause of peripheral neuropathy in world (not in industrialized countries). Treat with dapsone, rifampin and clofazimine. Tuberculoid disease: limited to a few hypoesthtic hailess skin plaques. High cell mediated immunity with Th1-type immune response. Treat with dapsone and rifampin.

How do I culture Lactose-fermenting Enterics?

MacConkey agar: Fermentation produces acid, turning colonies pink

Glycocalyx

Mediate adherence to surfaces - made of loose network of polysaccharides

No Cell Wall

Mycoplasma Ureaplasma

Aerobes

Nagging Pests Must Breath Nocardia Pseudomonas Mycobacterium tuberculosis (reactivates in apices of lungs b/c PO2 highest)

Gram Negative Cocci

Neisseria Moraxella catarrhalis

Strep. bovis (GDS)

Normal GI flora. S. gallolyticus (S. bovis biotype 1) can cause bacteremia and subacute endocarditis -- associated with colon cancer. Bovis in the blood = cancer in the colon. γ-hemolytic gram positive cocci in pairs and chains. Grows in bile but not 6.5%NaCl.

Enterococci (GDS)

Normal colonic flora. Cause UTI, biliary tract infection, subacute endocarditis (after GI/GU procedure). VRE is important source of nosocomial infection. Gram positive cocci in pairs and chains. Grow in 6.5%NaCl and bile. Variable hemolysis (often no hemolysis, or γ-hemolysis).

Actinomyces

Normal oral flora. Can cause oral/facial abscesses that drain though sinus tract. Forms yellow "sulfur" granules. Gram positive anaerobe that forms filament (looks like fungi). No need for acid-fast stain. Treat with penicillin. When you have filamentous bacteria, treatment is a SNAP (Sulfonamides for Nocardia, Actinomyces get Penicillin)

Staph. epidermidis

Normal skin flora. Contaminates blood cultures. Can infect prosthetic devices and IV catheters by producing adherent biofilm. Gram positive cocci in clusters. Catalase+ and coagulase-. Novobiocin sensitive

Identifying Strep spp

Optochin - Viridans is resistant, Pneumoniae is sensitive (OVeRPaSs) Bacitracin - GBS is resistant, GAS is sensitive (B-BRAS)

When to use PAS stain

PAS the Sugar stains glycogen and mucopolysaccharides. Used to diagnose Whipple Disease (Tropheryma whipplei)

Cutaneous Anthrax

Painless papule surrounded by vesicles -> ulcer with black eschar (painless, necrotic) -> uncommonly progresses to bacteremia and death

Pertussis toxin

Released by Bordetella pertussis A-B toxin that disables Gi protein, which increased cAMP impairing phagocytosis by host cell which allows microbe survival. This bug causes Whooping cough in children -- child coughs on expiration and whoops on inspiration (toxin may not be cause of the cough). This bug causes "100-day cough in adults

More on conjugate vaccines for Encapsulate Bacteria

Prevnar: pnuemoccocal conjugate vaccine -- PCV Pneumovax: unconjugated pneumococcal polysaccharide vaccine -- PPSV HiB: Conjugate Vaccine Meningococcal vaccine: Conjugated vaccine

Cereulide

Produced by B. cereus Causes nausea and emesis within 1-5 hours after ingestion of germinated spores (reheated riced syndrome). If ungerminated: watery, non-bloody diarrhea occurs 8-18 hours after ingestion.

C. difficile

Produces two toxins. Toxin A binds to brush border of gut. Toxin B is cytotoxic. Causes actin depolymerization -> cytosckeletal disruption ->pseudomembranous colitis -> diarrhea. Often secondary to antibiotic use (Clindamycin or ampicillin). Diagnosed by detection of either/both toxin through PCR. Treat with metronidozole or oral vancomycin. Recurrent cases can be treated with fidaxomicin or fecal microbiota transplant.

Edema toxin

Released by Bacillus anthracis A-B toxin that mimics adenylate cyclase, and produces cAMP. Likely causes characteristic edematous borders of black eschar in cutaneous anthrax

Botulinum toxin

Released by Clostridium botulinum A-B toxin. This is a protease that cleaves SNARE (soluble NSF attachment receptor), which is a set of proteins required for presynaptic vesicular fusion to cell membrane, thus blocking neurotransmitter release. Blocks release of Ach at NMJ, leading to flaccid paralysis/floppy baby. Found in honey and spoiled canned/bottled food. Treat with antitoxin.

Alpha toxin

Released by Clostridium perfringens Phosphidolipase (lecithinase) that degrades cell membranes. Leads to tissue degradation (myonecrosis) of gas gangrene and hemolysis (can see "double zone" of hemolysis on blood agar)

Tetanospamin

Released by Clostridium tetani A-B toxin. This is a protease that cleaves SNARE (soluble NSF attachment receptor), which is a set of proteins required for presynaptic vesicular fusion to cell membrane, thus blocking neurotransmitter release. Blocks release of GABA and glycine from Renshaw cells in spinal chord, thus disrupting the inhibitory signal and causing spasticity, risus sardonicus ("sardonic grin") and lockjaw. Prevent with tetanus vaccine. Treat with antitoxin, diazepam (for muscle spasms) and maybe vaccine booster.

Diphtheria Toxin

Released by Cornybacterium diphtheriae A-B toxin that inhibits protein synthesis by inactivating elongation factor (EF-2), causing pharyngitis eith pseudomembranes in throat and severe lymphadenopathy (bull neck)

Shiga-like Toxin (SLT)

Released by Enterohemorrhagic E. Coli (EHEC, E. coli 0157:H7). A-B toxin that inhibits protein synthesis by inactivating 60s ribosome subunit by removing adenine from rRNA. Enhances cytokine release leading to hemolytic-uremic syndrome (HUS). Unlike Shigella, EHEC does not invade host cells

Heat-labile toxin

Released by Enterotoxigenic E. coli (ETEC) A-B toxin that over-activates adenylate cyclase leading to increase in cAMP which increased secreation of Cl- in gut, causing H2O efflux (diarrhea)

Heat-stabile toxin

Released by Enterotoxigenic E. coli (ETEC) Over-activates guanylate cyclase leading to increase in cGMP which causes a reduced resorption of Na+, Cl- and H2O from gut (diarrhea)

Exotoxin A (Pseudomonas)

Released by Pseudomonas aeruginosa A-B toxin that inhibits protein synthesis by inactivating elongation factor (EF-2) and causes host cell death

Exotoxin A (Strep. pyogenes)

Released by S. pyogenes Binds to MHC II and TCR at unique binding site to cause hyper-release of IL-1, IL-2, IFN-γ, and TNF-α leading to shock. Toxic Shock Syndrome: Fever, Rash, Shock.

Shiga Toxin (ST)

Released by Shigella spp. A-B toxin that inhibits protein synthesis by inactivating 60s ribosome subunit by removing adenine from rRNA. Causes GI mucosal damage leading to dysentery. Also enhances cytokine release leading to hemolytic-uremic syndrome (HUS)

Toxic Shock Syndrome Toxin (TSST-1)

Released by Staph. aureus Binds to MHC II and TCR at unique binding site to cause hyper-release of IL-1, IL-2, IFN-γ, and TNF-α leading to shock. Toxic Shock Syndrome: Fever, Rash, Shock. Other S. aureus toxins may cause scalded skin syndrome (exfoliative toxin) and food poisoning (enterotoxin)

Streptolysin O

Released by Strep. pyogenes Degrades cell membranes. Lyses RBCs, contributes to β-hemolysis. Host Antibodies against Streptolysin O (ASO) can be used to diagnose rheumatic fever

Cholera toxin

Released by Vibrio cholerae A-B toxin that permanently activates Gs protein causing large increase in cAMP and leading to increased Cl- secretion in gut and H20 efflux ("rice water" diarrhea)

Encapsulated Bacteria

SHiNE SKiS Streptococcus pneumo H. influenzae type B Neisseria meningitides E. coli Salmonella Klebsiella pneumoniae BGS

How do I culture Fungi?

Sabouraud agar

Staph. saprophyticus

Second most common cause of uncomplicated UTI in women (after E. coli). Gram positive cocci in clusters. Catalase+ and coagulase-. Novobiocin resistant

IgA Protease

Secreted by Strep. pneumo, HiB, and Neisseria (think SHiN) which colonize respiratory mucosa. Enzymatically cleaves IgA.

Neisseria Gonorrheae

Sexually or perinatally transmitted. Causes gonorrhea, septic arthritis, neonatal conjunctivitis, PID and Fitz-Hugh-Curtis syndrome. Tx: ceftiaxone (+ azithromycin or doxy for possible chlamydia co-infection) Prevention: Condom use. Erythromycin ointment prophylaxis for neonates. No vaccine due to antigenic variation (various pilus proteins) Gram negative diplicocci without a polysaccharide capsule. Ferment glucose but not maltose (gonococci -- glucose)

Facultative Intracellular

Some Nasty Bugs May Live FacultativLY Salmonella Neisseria Brucella Mycobacterium Listeria Francisella Legionella Yersinia pestis

Type III secretion system

Some gram negative bacteria (ex: Pseudomonas, E. coli, Salmonella, Shigella) Called "injectisome." Needle-like protein appendage to facilitate direct delivery of toxins into eukaryotic host cell.

Periplasm

Space between plasma membrane and outer membrane in gram negative species

Spore forming bacteria

Spores are resistant to heat and chemicals. Have dipicolinic acid at their core. Have no metabolic activity. Autuclave (121°C for 15 min) to kill spores. Bacillus anthracis -- Anthrax (only polypeptide capsule) Bacillus cereus -- food poisoning (rice) Clostridium Difficile -- antibiotic associated pseudomemranous colitis Clostridium botulinum -- Botulism Clostridium tetani -- Tetanus Clostridium perfringens -- Gas gangrene Coxiella burnetii -- Q fever All are gram positive bacilli. Clostridia are obligate anaerobes.

Gram Positive Cocci

Staph Strep

Obligate Intracellular

Stay inside when it's Really Chilly and Cold Rickettsia Chlamydia Coxiella Rely on host cell ATP

Viridans Strep

Strep. mutans causes dental carries. Strep sanguinis causes endocarditis (make dextrans which bind to clots on damaged heart). α-hemolytic gram positive cocci in pairs and chains. Optichin resistant.

How do I culture C. diphtheriae?

Tellurite agar, Loffler medium

How do I culture Neisseria spp?

Thayer-martin Agar: Vancomycin (inhibits GP), Trimethoprim, Colistin (inhibits other GNs), Nystatin (inhibits fungi) Very Typically Cultures Neisseria

Which bugs don't gram stain?

These Microbes May Lack Real Color Treponema (too small -- use dark-field and fluorescent antibody stain) Mycobacterium (high lipid content -- use Acid fast for mycolic acids in CW) Mycoplasma (no cell wall) Legionella (mostly intracellular -- use silver stain) Rickettsia (intracellular parasite) Chlamydia (intracellular parasite, no classic peptidoglycan)

Strep. pneumoniae

Think MOPS: Meningitis, Otitis Media, Pneumonia, Sinusitis. Associated with rusty sputum. Can cause sepsis in asplenic or sickle cell patients. Virulence from capsule. α-hemolytic gram positive lancet shaped diplococci. Encapsulated. IgA protease. Think MOPS again: Most OPtichin Sensitive

Neisseria Meningetides

Transmitted by respiratory/oral secretions. Causese mengiococcemia, meningities and Waterhouse-Friderichsen syndrome. Tx: ceftriaxone or penicillin G Prevnetion: Rifampin, ciprofloxacin or ceftriaxone prophylaxis for close contacts. Vaccine. Gram negative diplococci with a polysaccharide capsule. Ferment glucose and maltose (MeninGococci -- maltose and glucose)

Capsule

Usually polysaccharide layer (except Bacillus anthracis, which is D-glutamate )

Pilus/Fimbria

mediates adherence of bacteria to cell surface; sex pilus forms attachment btwn two bacteria during conjugation