microbio 1

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What is the peptidoglycan layer in bacteria?: repeating disaccharides with 4 aas
gives rigid support and protects agains osmotic pressure
What enzyme catalyzes the formation of crosslinked chains?: transpeptidase aka penicillin binding protein
what is the role of the murein lipoprotein?: extends from the peptidoglycan layer to the outer membrane of the G+s
what is teichoic acid?: The major surface antigen of the cell wall/cell membrane of G+s. Induces TNF and IL1
Break down LPS: Where is it located? What are the parts of it.: Located on the outer membrane- G-s
Oligosaccharide unit- O-antigen
Center- core polysaccharide
Interior- Lipid A, disaccharide- endotoxin, induces TNF and IL1; the polysaccharide is the antigen.
What is the function of the plasma membrane?: oxidative and transport enzymes.
What is unique about bacterial ribosomes?: 50S and 30S
Erythromycin 50
tetracycline 30
What are the G+ bugs?: Cocci
Streptococcus- Cat -
Staphylococcus- Cat +

spore producing rods:
Bacillus
Clostridium
(Outer layer of the spore is the exospporium)

plain old rods:
Corynebacterium
Listeria (only G+ w/ endotoxin)
What is the G- diplococci?: Neisseria
What is the purpose of the following: periplasm capsule pilus/fimbria Flagellum Plasmid Glycocalyx: periplasm- fluid between cytoplasmic and outer membrane- where B-lactamases are.
capsule- protects from phagocytosis
pilus- mediates adherence of bacteria to cell surface, sex pilus for conjugation
Flagellum- motility- connected by basal body
plasmid- has genes for resistance, enzymes, toxins
Mediates adherence to surfaces, foreign
What is the role of: Catalase Peroxidase Superoxid sdismutase: Catalase-breaks down hydrogen peroxide
peroxidase- same
superoxide dismutase- breaks down the superoxide radical. w/o, not an aerobe.
What bugs have superantigens?: S. Aureus
S. pyogenes

Superantigens bind directly to MHC II and T-cell recptor, activating large numbers of T-cells to stimulate IL 1 and IL 2

S. aureus TSST-1, fever, rash, shock. (enterotoxins- food poisoning)

S. pyogenes- scarlet fever-strain SPE toxin --> toxic shock
What bugs have ADP Ribosylating toxins?: Corynebacterium diptheria
Vibrio cholerae
E. coli
Bordetella pertussis
What is the mechanism of diptheria toxin?: Inactivates elongation factor-2 causing pharyngitis and "pseudomembrane"
What is the mechanism of cholera toxin?: ASP ribosylation of G protein stims cAMP increasing the pumping of CL- and H2O into the gut
rice-water diarrhea
What is the mechanism of the E.Coli toxin?: Heat-labile toxin stimulates adenylate cyclase (like cholera) causing watery diarrhea. It also stimulates guanylate cyclase
What is the mechanism of Pertussis toxin?: Stims adenylate cyclase-> whooping cough, inhibs chemokine receptor causing lymphocytosis.
What is the mechanism of clostridium toxin?: alpha toxin causes gas gangrene, get double zone of hemolysis on blood agar
What is the mechanism of tatanus toxin?: Blocks glycine transmission-> lockjaw
What is the mechanism of botulinum toxin?: Blocks the release of Ach -> CNS paralysis
What is the mechanism of anthrax toxin?: one toxin is an adenylate cyclase
What is the mechanism of shiga toxin?: cleaves host cell rRNA, enhances cytokine release-> HUS
also caused by E. Coli O157:J7
What is the mechanism of S. pyogenes toxin?: streptolysin O is a hemolysin, Ag for ASo in rhumatic fever
What is the mechanism of endotoxin?: Activates macrophages:
IL-1- fever
TNF- Fever, hemorrhagic tissue necrosis
NO- hyoptension

Activates complement (alt path)
C3a- hypotension, edema
C5a- neutrophil, chemtaxis

Activates Hageman factor- Coag cascade-> DIC
What bugs do not gram stain well?: These Rascals May Microscopically Lack Color

Treponema - too thin (darkfield)
Rickettsia- Intracellular
Mycobacteria- acid fast, high lipid content
Mycoplasma- no cell wall
Legionella- intracellular (silver stain)
Chlamydia- intracellular
What is the difference in the Nesseria species in fermentation?: Menigococci- ferment maltose and glucose
Gonococci- ferment glucose
What bacteria produce a pigment?: S. aureus - yellow (gold)
P. Aeruginosa- blue-green
Serratia marcescens- red (maraschino cherries
What bugs use IgA proteases to colonize mucosal surfaces?: S. pneumoniae
Neisseria Meningitidis
N. Gonorrhoeae
H. Influenzae
In bacterial sex, what are the differences between conjugation, transduction and transformation?: conjugation- DNA transferred from 1 to another bacterium, prokaryotic- chromosomal or plasmid (F plasmid)
Transduction- DNA transferred by a virus from 1 cell to another (sperm back)
Transformation- purified DNA taken up by a cell
What is the difference between generalized and specialized transduction?: generalized is any gene (virulent)- bacterial DNA is detroyed, but may be accidently packaged like viral DNA
specialized is a specific gene (temperate) DNA is accidentally repilcated when viral DNA is being replicated.
What is the difference between a virulent and a temperate phage?: virulent- invade and replicate until the bacteria explode.

temperate- DNA is incorporated into bacterial DNA. (prophage) Bacteria with prophage are called lysogenic, they are genetic time bombs.
What is Gram, catalase adn coagulase +?: s. aureus
What is gram and catalase + and coagulase -?: Novobiocin sensitive
s. epidermidis
Novobiocin resistant
S. saprophyticus.
What is Gram +, catalase -, and alpha (green) hemolyitic?: S. pneumoniae- optochin sensitive, bile soluble
Viridans strep- optochin resistant, not bile soluble
What is G+, cat-, and shows Beta (clear) hemolysis?: Group A- s. pyogenes- Bacitracin sensitive
Group B- S. agalactiae- Bacitracin resistant
What is G+, cat-, and shows gamma (no) hemolysis: Enterococcus

peptostreptococcus
What type of media do you need to culture H. influenzae?: Chocolate agar with factors V (NAD) and X (hematin)
What type of media do you need to culture N. Gonorrheae?: Thayer-Martin (VCN) media
What type of media do you need to culture B. pertussis?: Bordet-Gengou (potato) agar
What type of media do you need to culture C. diphtheriae?: Tellurite plate, Loffler's medium, blood agar
What type of media do you need to culture M. Tuberculosis?: Lowenstein-Jenson
What type of media do you need to culture lactos-fermeting enterics?: Pink colonies on MacConkey's Agar
What type of media do you need to culture Legionella?: Charcoal yeast extract agar buffered with increased iron and cysteine
What type of media do you need to culture Fungi?: Sabouraud's agar
For what organisms would you use a silver stain?: Fungi, PCP, Legionella
For what organisms would you use a Giemsa's stain?: Borrelia, Plasmodium, trypanosumes, Clamydia
For what organisms would you use a Ziehl-Neelson stain?: acid fast
What gram - cocci is a maltose fermentor?: Nesseria Meningitidis
What G- is a maltose nonfermentor?: Nesseria gonorrhoeae
What are the Gram - coccoid rods? (4): H. influenzae
Pasteurella
Brucella
B. pertussis
What are some fast G- lactose fermenting rods?: Klebsiella
E. coli
Enterobacter
What are some slow G- lactose fermenting rods?: Citrobacter
Serratia
What are some non lactose fermenting Ox - G - rods?: Shigella
Salmonella
Proteus
What are some non lactose fermenting ox + G- rods?: Pseudomonas
What bugs are obligate aerobes?: Nagging Pests Must Breathe
Nocardia
Pseudomonas aeruginosa
M. tb
Bacillus
What are the obligate anaerobes?: Clostridium, Bacteroides, Actinomyces.
Foul smelling. hard to culture. Produce gas in tissue
What class of drugs require O2 to enter the cell and kill?: Aminoglycosides- don't work on obligate anaerobes.
What bugs are obligate intracellulars?: Stay inside when its Really Cold.
Rickettsia
Chlamydia
What bugs are facultative intracellular?: Some Nasty Bugs May Live FacultativeLY
Salmonella
Neisseria
Brucella
Mycobacterium
Listeria
Francisella
Legionella
Yersinia
What bugs make spores?: Clostridium
Bacillus

G+ rods
What bacteria are alpha hemolytic?: strep pneumoniae- cat -, optochin sensitive
Viridans strep- cat - and optochin resistant
What bacteria are beta hemolytic: Staph aureus- cat and coag +
Strep pyogenes cat - and biacitracin sensitive
strep agalactiae - cat - and bacitracin resistant
Listeria monocytogenes (tumbling motility, meningitis in newborns, unpasteurized milk)
What is the role of the M protein?: Group A strep, inhibs activation of complement, protects from phagocytosis.
However, plasma cells make Ab against it.
What is the role of Streptolysin O Streptolysin S: Group A strep enzyme.
O is oxygen labile. Inactivated by O2. Destroys red and white blood cells. allows for B-hemolytic ability. Antigenic

S- also b-hemolytic, not antigenic
What is the role of the pyrogenic exotoxin?: aka erythrogenic toxin
only found in a few strains, but can cause scarlet fever.
What does Group A strep cause?: pyogenic- pharyngitis, cellulitis, impetigo
toxigenic- scarlet fever, toxic shock-syndrome
Immunologic- rheumatic fever, acute glomerulonephritis.
When would you see tea colored urine with strep?: acute post-strep glomerulonephritis- hematuria.
What are the Bs of Group B Strep?: Bacitracin resistant, B-hemolytic, cause pneumonia, meningitis, sepsis mainly in Babies.

neonates- fever, vomiting, poor feeding, and irritability.
What are the 3 most common bugs of meningitis under 3 months old?: Strep B, E. coli, Listeria
What's up with viridans strep?: alpha hemolytic (viridans means green)
dental caries, S. mutans, and endocarditis, S. sanguis (blood). Optochin resistant.
What does S. pneumoniae the most common cause of (4 things)?: Meningitis
Otitis media
Pneumonia
Sinusitis

Encapsulated, IgA protease
"rusty" sputum
sepsis in sickle cell, and splenectomy
if an alcoholic vomits then develops foul smelling sputum, what organisms are most likely?: anaerobes
Middle age male with acute monoarticular joint pain and bilateral bell's palsy?: lyme disease (ixodes)
What type of immunoglobin is reacting in M. pneumoniae croagglutinins?: IgM
What do WBC casts indicate?: pyelonephritis
what cell is deficient in someone with tetany and candidiasis. With hypocalcemia and immunosuppresion?: DiGeorge- T cell
Thorn prick from a rose, with ulcers along lymph drainage?: Sporothrix schenckii
What causes cauliflower lesions by yeast?: the broad based budding blasto
What would cause redness and swelling of the breast after breast feeding, fluctuant mass?: S. Aureus causing Mastitis
Young child has recurrent lung infections and granulomatous lesions. What is the defect?: Neutrphils lack NADPH oxidase
20 y/o college student presents with lymphadenopathy, fever, hepatospleno. Serum agglutinates in Sheep RBCs?: EBV infection, B Cell is infected
What organism would cause endocarditis 3 wks after getting a heart valve replacement?: S. aureus or S. epidermidis
Why would someone get megacolon and diarrhea after a round of clindamycin?: C. difficile overgrowth
What bug can be grown in 6.5% NaCl?: Enterococci
What is the change made for vancomycin resistance?: d-ala-d-ala is now d-ala-lactate preventing vanco binding
What cancer is associated with S. bovis?: colon cancer
Which strep are paired up?: S. pneumoniae
What is the Quellung reaction?: helps identify pneumococcus- anti serum, the capsule will swell.
Which one is optochin sensitive: viridans or pneumo?: pneumo
What is the role of Protein A?: Staph
bidn the Fc portion of IgG, protects from opsonization
How does coagulase protect the bacteria?: forms fibrin around the bacteria protecting from phagocytosis
What does staph aureus cause?: Inflammatory- skin infections, organ abscesses, pneumonia
Toxin- TSST, SSS
TSST is a superantigetn
What is the toxin involved in scalded skin syndrom: Exfoliatin
Which toxin causes food poinsoning?: enterotoxins (heat stabile)
What is the role of hyaluronidase?: breaks down proteoglycans in CT
What is the role of staphylokinase?: lyses formed fibrin clots
What are the symptoms of Toxic Shock Syndrome?: high fever, nausea, vomiting, watery diarrhea are sudden
diffuse erythema comes on a little later
When is Staph epidermidis a problem?: Hospitalized patients with IVs or Catheters.
Who gets S. Saprophyticus?: women, common community aquired UTI.

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