Micro bacteria 1

felumore's version from 2016-02-16 17:25


Question Answer
How to differentiate gram positive cocci?catalase test ; anaerobes do not have catalase
positive -- facultative anaerobes-- staphylococci,
negative -- anaerobes --> streptococci/ enterococci-
How to differentiate staphylococci into different types?Coagulase test;
-positive-- staphylococcus--bind fibrinogen to form fibrin
- negative -- Staphylococcus epidermidis, S. saoriohyticus
Yellow colonies in Mannitol Salt Agar, coagulase positiveStapylococcus aureus-- salt tolerant.
- mannitol salt Agar -S. aureus ferment mannitol--> yellow
novobiocin resistant coagulase negative cocciStaohylococci saprophyticus
--S. epidermidis - not resistant
Green colony in blood agar, catalase negative cocciStreptococci pneumoniae, Viridans streptococci
-- green in blood agar-- alpha hymolytic
Yellow colony in blood agar catalase negative cocciStreptococci pyogenes, Streptococci agalactiae
Yellow in blood agar--> beta hemolysis
Clear colony in blood agar, catalase negative.Enterococcus
non-hemolytic -
optochin susceptible, bile soluble diplococciStreptococci pneumoniae -
Optochin resistant, Bile resistant, gram positive, coagulase negative cocciStreptococci viridans , Streptococci mitis
Bacitracin susceptible Lancefield group A, gram positive, catalase negative cocciStreptococcus pyogene
PYR positive = pink
Lancefield group D antigen positive,
black precipitate on bile esculin agar
Enterococcus -
resistant to bile sale
clear on blood agar
Enterococcus faecalis, faeciumGram positive cocci catalase anaerobes- non hymolitic, normal GI
Aerobic, gram positive spore-forming rodsBacillus
Anaerobic, gram positive spore-forming rodsClostridium -
Gram positive - nonspore-forming rods, club-shaped
- black- browncolonies on tellurite agar
catalase positive -
Anaerobic, gram positive non spore forming rodsLactobacillus
Gram positive, nonspore forming rods, grows at low T, aerobicListeria -
Gram positive non spore forming rods, aerobic, acid fast, filamentous shapeNocardia-
Gram positive non spore forming rods , anaerobe, filamentous shapeActinomyces -
Gram negative diplococci,
Grow on Thayer-Martin agar ( chocolate agar w/ antibiotics) @ CO2 5%, kidney shape, oxidase positive, catalase positive, ferment glucose
- Neisseria gonorrheae ( ferment glucose)
- Neisseria meningitidis ( ferment glucose + maltose ) -
Gram negative cocobacilli
Aerobes, non fastidious , oxidase positive, catalase negative, easy growth on blood agar
Gram negative cocobacilli- diplococcus
Aerobes, non fastidious , oxidase positive, catalase positive, non fastidious, blood agar, no fermentation
Gram negative coco bacilli, Aerobes
fastidious, Bordet-Gengou, Regan- Lowe agar, NAAT used - 7-12 days incubation
Gram negative coco bacilli, Aerobes
nonfastidious, oxidase negative, BCYE chocolate agar, 3days incubation
Gram negative coco bacilli, Aerobes
fastidious, oxidase positive, catalase positive, blood agar
Gram negative bacilli, aerobes, straight rods, oxidase positive, green pus, faculatative aerobes, no fermentationPseudomonas-
Gram negative bacilli, aerobes, straight rods, poor gram stain, Silver stain positive, direct fluorescent antibody test, BCYE agar, systeine, ironLegionella-
Gram negative bacilli, aerobes, curved, - gull wing oxidase positive, need less O2 tension, @ 42C*Campylobacter-
Gram negative bacilli, aerobes, comma-shaped, oxidase positive, alkaline environmentVibrio-
Gram negative bacilli, aerobes, Urease positive Oxidase positiveHelicobacter-
Gram negative bacilli, facultative anaerobes, oxidase positive coccobacilli, require factor X and factor V, need chocolate agarHaemophilus-
Gram negative bacilli, facultative anaerobes, oxidase positive, cocobacilli, bipolar stainingPasturella-
Gram negative bacilli, facultative anaerobes, oxidase negative, Ferment glucose, Lactose utilization ( pink in MacConkey agar -- positive, clear---negative)Enterobacteriaceae
Gram negative bacilli, facultative anaerobes, oxidase negative, lactose fermenting, produce H2SCitrobacter-
What is the test to determine Helicobacter?Urease test --- positive -
Gram negative bacilli, facultative anaerobes, oxidase negative, lactose fermentingenterobacter-
Gram negative bacilli, facultative anaerobes, oxidase negative, lactose fermenting, motilE Coli-
Which medium to use when finding if enterobacteriaceae is E scherichia Coli, or Shigella?MacConkey agar - pink - E.coli ( ferment lactose ) , pale, Shigella-
Gram negative bacilli, facultative anaerobes, oxidase negative, lactose fermenting, non-motil, encapsulatedKlebsiella pneumoniae-
Gram negative bacilli, facultative anaerobes, oxidase negative, non- lactose fermenting, make H2S, non motile, Hektoen enteric agar -greenShigella-
MacConkey -- clear
Gram negative bacilli, facultative anaerobes, oxidase negative, non- lactose fermenting, non- H2S producing, Bipolar staining, urease positiveYersinia pestis, enterocolitica-
Gram negative bacilli, facultative anaerobes, oxidase negative, non- lactose fermenting, H2S producing , cause of UTI, urease positive, swarming motilityProteus-
Gram negative bacilli, facultative anaerobes, oxidase negative, non- lactose fermenting, make H2S, motileSalmonella-
Hektoen enteric agar showed green , Oxidase test was negative, which bacilli?Shigella
-- green- non-lactose fermenting, no black dots--> non-H2S producing -
Hektoen enteric agar showed yellow- orange and black precipitate, which bacilli?Citrobacter -
yellow--> lactose fermenting, black--> make H2S
- Hekton inhinit gram positive
Which medium can determine pseudomonads?Cetrimide agar
--> green, bule yellow green -
How can you differentiate Salmonella and shigella?Hekton agar
Salmonella-- black precipitates -
What can be identified by urease test?Helicobacter, Proteus, Ureaplasma, Nocardia, cryptococcus -
positive= pink
Spirochetes, Gram negative cell wall, ThinTreponema-
Spirochetes, Gram negative cell wall, visible in blood smear, fastidiousBorrelia-
Spirochetes, Gram negative cell wall, hook obligate aerobe, grow @ 28-30 CLeptospira -
does not Gram stain, obligate intracellular,
have LPS, no PG, - reticulate body, elementary body
- within phagosome
Chlamydia, Chlamydophila- cannot make own ATP-
does not Gram stain, obligate intracellular, no PG, no LPS, giemsa stain, found in cytoplasmOrientia-
does not Gram stain, obligate intracellular, thin PG, Giemsa stain found in cytoplasmRickettsia-
does not Gram stain, obligate intracellular, no PG, no LPS, Giemsa or wright stain, in phagocytic vacuole, elementary bodies, reticulate bodiesEhrlichia, Anaplasma-
does not Gram stain, obligate intracellular, gram negative cell wall, - Acidophile, Small cell variant (Spore) , large cell variant, found in phagolysosomeCoxiella-
Mycoplasmasmallest bacteria require sterol, fried egg appearance -
Mycobacteiawaxy cell envelope, small, rods, need heat to stain -


Question Answer
Bacterial structural toxinLPS, LOS, PG, lipoteichoic acid, lioiarabinomannan--- cause immune response -
what is endotoxin in gram negative cell wall?Lipid A -
antibiotic role on endotoxin relasebeta lactam target target penicillin binding protein --> cause release of LPS -
LPS released from lysed cell activate___macrophage- via CD14, TLR 4 --> also activate cytokine secretion
How PG fragments, lipoteichoic acid activate immune response?Bind to TLR 2,6 on macrophage--> cytokine relase -
Receptors that activate phagocytosis-mannose receptor, compleme - Fc receptors- --
blocked by capsules -- prevent phagocytosis
What is antigen responsible for serotyping?K antigen -
What is the role of streptococcus pyogene hyaluronic acid capsule on virulence?minic host cell-
Immune response to bacterial carbohydrateinnate- complement via lectin pathway,
humoral - T independent activation on B class switching -
quorum sensing in bioform formation-when cell density increase, it activate transcription factor for bioform
Effect of rifampicin on bioformnot effective, due to dormancy of bacteria -
super antigenbind MHCII and TCR cause T proliferation
-staphylococcal enterotoxin, TSST, streptococcal pyrogenic toxin
exotoxins that damages membrane- phospholipases,
Cperfringens alpha toxin
--> cause gas gangline
- surfactants -
Listeriolysin O -> escape form phagolysosome
what is AB toxin?intracellular exotoxin
A= active
B= binding to specific receptor
--> induce endocytosis
corynebacterium diphtheriae diphtheria toxin
Effectorsintracellular exotoxin
- use type III, IV secretion
-- produce inappropriate signals
-Salmonella Sip protein
How Botulinum toxin can cause either flaccid, or spastic paralysis.-Target different ganglions.
Neisseria meningigitidisGram negative, diplococcus, kidney bean shaped, Oxidase positive, calatase positive, non motile, type IV pili twitching, - NO LPS, has LOS
N. meningitidis diseasesepsis, meningitis - infant,
- via nasopharynx, respiratory transmission
-- initial petechiae rash, rapid progression to sepsis
Serous groups of Neisseria meningitidis-Based on O antigen -
A, B, C, Y, W-135 ( vaciccine target)
A-- related outbreak
virulence factor, neisseria meningitidis-- Pili - binding,
-- IgA protease- cleave IgA
--capsule - prevent phagocytosis,
--Neisserial porin,
-- PG - fragment cause immune response,
--LOS- exotoxin
How N. meningitidis act on hostlarge LOS release due to blebing--> cytokine release
Lipid A recognition by TCR 4, CD14 -
N. meningitidis diagnosisLumbar puncture, blood culture, Gram stain,
Pseudomonas AeruginosaGram negative bacillus, motile, oxidase negative, no fermentation,
green in fluorescent, fruity odor -
Pseudomonas Aeruginosa infectionImmunocompromised
skin, respiratory keratitis, otitis externa -
Pseudomonas Aeruginosa virulence factor-Adhesin--type IV pili
- LPS- endotoxin
- polysaccharide
- exotoxins -
Pseudomonas Aeruginosa--- exotoxin- Exotoxin A-- AB toxin, ADP ribosylate EF2 on diphthamide resideue -
Type III exotoxin---ExoS.T, U Y
---> Exo S; prevent DNA synthesis, Exo T; inhibit phagocytosis
-- phospholipase C
--phamnolipid-- surfactant
-- leukocidin
Pseudomonas Aeruginosa --exoenzymeElastase -- lung damages -cause chronic inflammation in CF
cyctic fibrosis-- prone to infection
-- cause bioform in CF lung
Pseudomonas Aeruginosa- biofilm formationadhesion -type IV pilli, flagella-
- make exopolysacchride; Pel, Psl
- Alginate in late biofilm
Straphylococcus aureusgram + clusters
Catalase +, coagulase +, beta hemolytic , yellow colonies, mannitol fermentation -salt tolerant,
--Penicillin resistance, pyogenic
-- normal flora,
Straphylococcus aureus - transmissionhand hygiene- respiratory, skin -
Straphylococcus aureus - virulence factorType 5, 8 capsule, bioform
cellulitis, toxic shock syndrome, scaled skin syndrome -
- adhesin -- clumping factor A, B
- Protien A- bind Fc of host/s Ig s
- Teichoic lipoteichoic acid
cytotoxin of Straphylococcus aureus- Alpha toxin -- pore forming
- beta toxin -- sphingomyelinase-- break membrane -
- gamma toxin,-- PVL - high affinity to leukocyte
- delta toxin
Straphylococcus aureus - food poisoningingestion of enterotoxin- SEA, SEB, SEC -
Straphylococcus aureus- toxic shockTSST1 - mestrual related -
Straphylococcus aureus- scalded skin syndromeSSSS -exfoliatin from bacteria degrade desmosomes--> baby -
Superantigen, organism, exotoxin, disease1) Staphylococcus aureus --- TSST1 ( enterotoxin F)---> Toxic shock , SEA, SEB, SEc.... --> food poisoning
2) Streptococcus pyogenes , pyrogentic toxin--> toxic shock, necrotizing fascitis
Cytolysins, organisms, exotoxin, disease1) Clostridium perfringen-- alpha toxin ---> gas gangline
2) Listeria monocytogens -- listeriolysin --> neonatal meningitis
3) pseudomonas aeruginosa--- phospholipase C
4) Straphylococcus aureus -- alpha toxin, beta toxin, gamma toxin, ---> abscesses
5) E coli-- alpha hemolysin --- UTI
AB toxin, organism, exotoxin, disease1) Clostidium, botulinum, AB, botulinum toxin
2) Clostridium tetani, tetanus neurotoxin--> tetanus
3) Corynebacterium diphtheriae -- diphtheria toxin--> diphtheria
4) Pseudomonas aeruginosa -- exotoxin A -via ADP tibosylation
5) vibro cholerae --- cholera toxin
6) E coli--- heat labile enterotoxin--> traveller's diarrhea, Vero toxin--> hemorrhagic colitis
Effectors ( injected toxins), organisms, exotoxin, diseased1) Salmonella -- Sip -- diarrheas
2) Pseudomonas aeruginosa -- ExoS, T, U -
3) H pylori -- Cag A -- ulcer