Microbiology - Basic Bacteriology

eesohbel's version from 2015-08-03 22:28

Section 1

Question Answer
Peptidoglycangives support, protects against osmotic pressure, sugar backbone w/cross-linked peptide side chains
Cell wallonly in G+, major surface Ag, makes peptidoglycan for support, *Lipoteichoic acid induces TNF and IL1
outer membraneonly in G-, site of endotoxin (LPS), major surface Ag, lipid A induces TNF/IL1- polysaccharide is the Ag
Plasma membrane site of oxidative/transport enzymes, lipoprotein bilayer
Ribosome50s and 30s subunits
Periplasmbetween cytoplasmic membrane and outer membrane in G-, has hydrolytic enzymes, including B-lactamases
Capsuleprotects against phagocytosis, made of polysaccharide (except bacillus anthracis which has D-glutamate)
Pilus/fimbriamediate adherance of bacteria to cell surface, sex pilus forms during conjugation, made of glycoprotein
Sporeprovides resistance to dehydration, heat, and chemicals, has keratin-like coat, made of dipicolinic acid
Glycocalyxmediates adherence to surfaces, esp foreign surfaces (catheters), made of polysaccharide

Section 2

Question Answer
Circular Gram PositivesStaph and Strep
Circular Gram NegativesNeisseria
Branching filamentousActinomyces and nocardia (weakly acid fast)
Pleomorphic morphologyrickettsiae, chlamydiae
Spiral bacterialeptospira, borrelia (Giemsa), treponema
No cell wall bacteriamycoplasma (has sterols and no cell wall)
Mycolic acid bacteriamycobacteria, high lipid content
Gram Postive Rodsclostridium, corynebacterium, bacillus, listeria, mycobacterium (acid fast)
Gram Negative Rods: EntericsE coli, shigella, salmonella, yersinia, klebsiella, proteus, enterobacter, serratia, vibrio, campylobacter, helicobacter, pseudomonas, bacterioides
Gram Negative Rods: Respiratory bugsHaemophilus, Legionella, Bordetella
Gram Negative Rods: Zoonotic bugsFrancisella, Brucella, Pasteurella, Bartonella

Section 3

Question Answer
Gram Stain LimitationsThese Microbes May Lack Real ColorTreponema, Mycobacteria, Mycoplasma, Legionella, Rickettsia, Chlamydia
Giemsa stainCertain Bugs Really Try my Patience
Chlamydia, Borrelia, Rickettsiae, Trypanosomes, Plasmodium
PAS (periodic acid-Schiff)Stains glycogen, mucopolysaccs- used to dx Whipple's disease (tropherymam whippelii)
Ziehl-Neelsenacid fast orgs (Nocardia, Mycobacterium)
India inkcryptococcus
Silver stainfungi (pneumocystis), legionella, helicobacter pylori
H flu culturechocolate agar w/factor V (NAD+) and X (hematin) or can be grown with staph aureus which provides factor V through hemolysis of RBCS
N. gonorrhoeae cultureThayer Martin media (VPN)- Vancomycin (no G+), polymyxin (no G-), Nystatin (no fungi)
B. pertussis culturepotato agar (Bordet-Gengou agar)
C. diphtheriae culturecysteine-tellurite plate, Loffler's media
M. tuberculosis culturelowenstein-jensen agar
M. pneumoniae cultureeaton's agar
Legionella culturecharcoal yeast extract agar
Fungi culturesabouraud's agar
EMB agargrow E. coli on eosin-methylene blue and see blue/black colonies with green sheen
MacConkey's agargrow lactose fermenting enterics and see pink colonies from acid. ConKEES grow on this agar. Citrobacter, Klebsiella, E. Coli, Entercobacter, Serratia
blue/purple staininggram positive
pink/purplegram negative
blood agar containing bile and hypertonic salinecan be used to differentiate enterococci from nonenterococcal group D strep. nonenterococci can grow in the presence of bile but NOT in the prescence of hypertonic saline

Section 4

Question Answer
Obligate aerobesNagging Pests Must Breathe- nocardia, pseudomonas, mycobacterium, bacillus
Obligate anaerobesFrankly Can't Breathe Air- Fusobacterium, Clostridium, bacteroides, actinomyceS. s- no catalase and/or superoxide dismutase-->susceptible to oxidative damage, foul smelling and hard to culture, make gas in tissue (CO2/H2)
what antibiotics are ineffective against anaerobesaminOglycosides because require oxygen to enter into bacterial cell
Obligate intracellularrickettsia, chlamydia, coxiella
Facultative intracellularSome Nasty Bugs May Live FacultativeLY- Salmonella, neisseria, brucella, mycobacterium, listeria, francisella, legionella, yersinia
Urease + bugsCH PUNKSS
Pigment producing bacteriaactinomyces israelli (yellow sulfur), S. aureus (yellow), Pseudomonas aeruginosa (blue green), Serratia (red)
Protein AS. aureus, binds Fc region of Ig, prevents opsonization and phagocytosis
IgA proteaseenzyme that cleaves IgA, secreted by strep pneumo, H. flu, and Neisseria (SHiN). Can colonize respiratory epithelium
M proteinhelps prevent phago (group A strep)

Section 5

Question Answer
Positive quellung rxnif encapsulated bug is present capsule swells when anticapsular antisera are added
Encapsulated bacteria+ quellung, SHiNE SKiS
Step Pneumo, H. influenza type B, Neisseria meningitidis, E. coli, Salmonella, Klebsiella pneumoniae, group B Strep
Capsules have virulence vactor, SHiN makes IgA protease, cause meningititis, and take up DNA from environment
Exotoxin sourcesome G+ and G-
Endotoxin sourceouter cell membrane of most G- bacteria and Listeria
Exotoxin and Endotxin secreted from cellexo is secreted from cell, endo is not
Chemistry of exotoxin and endotoxinexo made of polypeptdes, endo made of LPS
Location of genes for exo and endotoxinsexo is plasmid/bacteriophage, endo is bacterial chromosome
Toxicity of exo vs endotoxinshigher for exo (1microgram)
Clinical effects of endotoxin and mode of actionfever and shock, production of TNF, IL-1 and IL-6
Antigenicity of exo vs endotoxinexo has high titer antibodes called antitoxins, endotoxin is poorly antigenic
Vaccine use of exo or endotoxinstoxoids used as vaccines for exotoxins, no vaccines from endotoxins
Heat stability for exo vs endotoxinsexo destroyed at 60deg, endotoxins stable at 100 for 1 hr


Question Answer
Induces IL-1, IL 6, TNF-alphaG+ Lipoteichoic acid
Induces IL-1 and TNF-alpha onlyG- Outer Membrane (LPS endotoxin)
Responsible for septic shockG- LPS endotoxin
Contain beta lactamaseG- Periplasmic space
Structures unique to G-Outer membrane (LPS endotoxin),Periplasmic space,Porin
Facilitates conjugationPilus (Sex pilus, or F pilus)
Bacterial ribosomes? 50S and 30S
Transferred during conjugation? Plasmid
Loose network of polysachharidesGlycocalyx biofilm
Organized network of polysaccharidesGlycocalyx capsule
Takes up naked DNA Transformation
How does transformation work?When a cell is lysed, its DNA fragments float around and can be incorporated into living bacteria
What bacteria can transform?S. pneumo, H. influenza (type b), Neisseria [SHiN]
Plasmids transferred via sex pilusConjugation, mediated by the bacterial penis
Transfer of DNA segments via excision and reintegrationTransPosition: Transposons jump
Flanking chromosomal DNA is found in?Transposons
DNA transfer mediated by viruses?TransDuction: part of lysed bacterial DNA gets incorporated into viral capsid
Provides support in cell wallPeptidoglycan
Unique to Gram positives?Cross-linked peptidoglycan layer, lipoteichoic acid
EndotoxinEdema via C3a
Nitric oxide - Hypotension/shock
Outer membrane - LPS in G(-) outer membrane (Listeria is only G+ with endotoxin)
TNF-a - hemorrhagic tissue necrosis
eXtremely heat stable
IL-1 - fever
Neutrophil chemotaxis via C5a
Bacterial growth curvelag phase (metabolic activity), log (rapid cell division), stationary (nutrient depletion slows growth, spores form in some), bacterial death phase due to inc. waste products and nutrient depletion
Transformationtake up DNA from environment (competence),many bacteria can have this but specifially SHiN: Spneumo, Hflu, Neisseria
Conjugation F+ x F-F+ plasmid has genes for conjugation, otherwise they are F-, plasmid replicated/transferred thru pilus from F+ cell, plasmid DNA only (no chromosomal genes)
Conjugation F- x HfrF+ plasmid can be incl. into bacterial xsomal DNA termed Hfr cell, transfer of plasmid AND xsomal genes
Generalized transduction"packaging event", lytic phage infects bacteri-->cleavage of bacterial DNA and synth of viral proteins-->part of bacteria xsomal DNA can be put into viral capsid
Specialized transduction"excision event", lysogenic phage infects bacterium-->viral DNA into bacterial xsome, when phage DNA is excised flanking bacterial genes may be excised also, DNA into phage viral capsid and can infect another bacterium
Transpositionsegment of DNA can jump from 1 location to another, transfer genes from plasmid to xsome and vice versa, when excision happens some flanking xsomal DNA can be incoporated into plasmi and transferred to other bacterium
Lysogeny, specialized transductionABCDE, shigA-like toxin, botulinum toxin, cholera toxin, diphtheria toxin, erythrogenic toxin of S. pyogenes


Question Answer
GiemsaChlamydia, Borrelia, Rickettsia, trypanosomes, Plasmodium, Histoplasma
PASGlycogen: T. whipplei
Ziehl-Neelson[carbol fuschin]: Acid fast (Nocardia, Mycobacteria) and Protozoa (Cryptosporidium)
India inkCryptococcus neoformans
Silver stainFungi (PCP), Legionella, Helicobacter pylori
No cell wall, sterolsMycoplasma
Mycolic acid, lipid richMycoBacteria
Which organisms don't gram stain?Treponema, Mycobacteria, Mycoplasma, Legionella, Rickettsia, Chlamydia "These Microbes May Lack Real Color"
Which bacteria are encapsulated ?SHINE SKiS
strep pneumo, h. flu, neisseria meningitidis, e. coli, salmonella, klebsiella, and group B strep


Question Answer
Degrades H2O2 into H2O and bubbles of O2Catalase test
Catalase+ organismsNocardia, Pseudomonas, Listeria, Aspergillus, Candida, E. coli, Staphylococci, Serratia, Bukholderia, Serratia, Nocardia [Cats Need PLACESS to hide]
Which population is susceptible to Catalase + Organisms?Chronic granulomatous disease (NADPH oxidase deficiency)
No NADPH: Can't convert H2O2 to ROS
Cat+ organisms gobble up the H2O2
CoagulaseCoagulates blood
Allows binding to fibrin and fibrinogen (easier phagocytosis)
Cocci in clustersStaph
Cocci in pairs and chainsStrep
Partial hemolysisAlpha hemolysis (green): S. Pneumonia and S. Viridans
G+ DiplococciS. Pneumonia
No hemolysisGamma hemolytic: Enterococcus
G+ RodsClostridium
G+ Branching filamentsActinomyces (not acid fast) and Nocardia (acid fast)
Gold pigmentS. aureus
Yellow pigmentActinomyces Israelii
Green-blue pigmentPseudomonas
Red pigmentSerratia marcecens
Giemsa stainRickettsia, Chlamydia, Borrelia bergdorferi
How do you diagnose Mycoplasma pneumoniaCold agglutinins (IgM): Agglutinate or lyse RBC's in cooooold

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