Micro Flashcards
1
Q
peptidoglycan
A
sugar backbone cross-linked by transpeptidase
2
Q
gram positive cell wall
A
lipoteichoic acid (induces TNF and IL-1)
3
Q
gram negatives outer membrane
A
site of endotoxin (LPS); lipid A induces TNF and IL-1; O polysaccharide is the antigen
4
Q
periplasm
A
contains beta lactamases; space between cytoplasmic and outer membranes in gram negatives
5
Q
capsule
A
polysaccharide (except B. anthracis, which contains D-glutamate)
6
Q
glycocalyx
A
polysaccharide which mediates adherence to foreign surfaces
7
Q
contain sterols and no cell wall
A
mycoplasma
8
Q
contain mycolic acid
A
mycobacteria
9
Q
common infection forming intraabdominal abscess
A
bacteroides fragils
10
Q
bugs that do not gram stain well
A
Treponema (dark-field microscopy, fluorescent Ab), Rickettsia (intracellular), mycobacteria (carbolfuchsin in acid-fast), mycoplasma, legionella pneumophila (silver stain), chlamydia (intracelluar, lacks muramic acid)
11
Q
Giemsa stain
A
chlamydia, borrelia, rickettsiae, trypanosomes, plasmodium
12
Q
PAS
A
stains glycogen; used to diagnose Whipple’s disease
13
Q
Ziehl-Neelsen
A
nocardia, mycobacterium
14
Q
india ink
A
cryptococcus neoformans
15
Q
silver stain
A
fungi, legionella, H. pylori
16
Q
H. influenza culture
A
chocolate agar with factors V (NAD+) and X (hematin)
17
Q
N. gonorrhoeae, N. meningitidis culture
A
Thayer-Martin (VPM): vancomycin, polymyxin, nystatin
18
Q
B.pertussis culture
A
Bordet-Gengou agar
19
Q
C. diphtheriae culture
A
Tellurite plate, Loffler’s media
20
Q
M. TB culture
A
Lowenstein-Jensen agar
21
Q
M. pneumoniae culture
A
Eaton’s agar
22
Q
lactose-fermenting enterics culture
A
pink colonies; E. coli also grown on eosin-methylene blue agar
23
Q
legionella culture
A
charcoal yeast buffered with cysteine and iron
24
Q
fungi culture
A
sabouraud’s agar
25
obligate aerobes
nocardia, pseudomonas (may use nitrates as terminal electron acceptors in environments with low O2), mycobacterium TB, bacillus
26
obligate anaerobes
clostridium, bacteroides, actinomyces; lack catalase and/or superoxide dismutase
27
aminoglycosides against anaerobes
not effective (reguire O2 to enter into bacterial cell)
28
obligate intracellular bugs
rickettsia, chlamydia
29
facultative intracellular bugs
salmonella, neisseria, brucella, mycobacterium, listeria, francisella, legionella, yersenia
30
encapsulated bacteria
positive quellung reaction; strep pneumonia, H. influenza type B, neisseria meningitidis, E. coli, salmonella, klebsiella pneumonia, group B strep
31
catalase-positive organisms
pseudomonas, listeria, aspergillus, candida, E. coli, S. aureus, serratia; pts with chronic granulomatous disease (NADPH oxidase deficiency) have recurrent infections
32
urease-positive bugs
cryptococcus, H. pylori, proteus, ureaplasma, nocardia, klebsiella, S. epidermidis, S. saprophyticus
33
actinomyces israelii pigment
yellow sulfur granules
34
s. aureus pigment
yellow
35
pseudomonas pigment
blue-green
36
serratia marcescenes pigment
red
37
protein A
binds Fc portion of Ig; S. aureus
38
IgA protease
S. pneumonia, H. influenza type B, Neisseria
39
M protein
group A strep
40
live attenuated vaccine
more effective in generating prolonged mucosal IgA secretion than killed vaccine
41
corynebacterium diphtheriae toxin
diphtheria toxin (ADP ribosylating AB toxin); inactivates elongation factor 2-->inhibits protein synthesis; pharyngitis with pseudomembranes and severe lymphadenopathy
42
pseudomonas toxin
exotoxin A (ADP ribosylating AB toxin); inactivate elongation factor 2--> inhibit protein synthesis
43
shigella toxin
shiga toxin (AB); inactivates 60S ribosome (removes adenine from rRNA, lyses 28sRNA)-->inhibits protein synthesis; GI mucosal damage, enhances cytokine release-->HUS
44
EHEC toxin
shiga-like toxin; inctivates 60S-->inhibits protein synthesis; does not invate host cells unlike shigella
45
ETEC toxin
heat-labile: increased cAMP-->increased Cl- secretion; heat-stable: increased cGMP--> decreased resoprtion of NaCl
46
bacillus anthracis toxin
edema factor; increases cAMP; black eschar
47
vibrio cholerae toxin
cholera toxin (affects apical ion transport); increased cAMP (permanentaly activates Gs)--> increased Cl- secretion; rice-water diarrhea
48
bordetella pertussis toxin
pertussis toxin; increased cAMP (disables Gi)--> impairs phagocytosisl whooping cough: cough on expiration and whoops on inspiration
49
clostridium tetani toxin
tetanospasmin; cleave SNARE; muscle rigidity, lock-jaw, inhibits release of inhibitory NT
50
clostridium botulinum toxin
botulinum toxin; cleaves SNARE; flaccid paralysis, floppy baby, prevents release of ACh
51
clostridium oerfringens toxin
alpha toxin (phospholipase that degrades tissue and cell membranes); degradation of phospholipid C-->myonecrosis and hemolysis
52
strep. pyogenes toxin
streptolysin O (protein that degrades cell membranes); lyses RBCs; host Ab against toxin (ASO) used to diagnose rheumatic fever
53
staph aureus toxin
toxic shock syndrome toxin; bring MHC II and TCR in proximity to outside of antigen-binding site-->release of IFN gamma and IL-2; toxic shock syndrome, scalded skin syndrome
54
strep pyogenes superantigen toxin
exotoxin A; bring MHC II and TCR in proximity to outside of antigen binding site-->release of IFN gamma and IL-2; toxic shock syndrome
55
which phase of bacterial growth do penicillins and cephalosporins act on
exponential/log
56
transformation
ability to take up naked DNA; Strep pneumonia, H. influenza type B, Neisseria; add deoxyribonuclease to environment-->no transformation
57
conjugation
transfer of plasmid, no transfer of chromosomal genes
58
F+ plasmid
can become incorporated into chromosomal DNA
59
transposition
excision and reintegration of segment DNA
60
generalized transduction
lytic phage infects bacterium-->parts of bacterial chromosomal DNA become packaged into viral capsid-->phage infects another becterium, transferring genes
61
specialized transduction
viral DNA incorporates into bacterial chromosome
62
toxins acquired through specialized transduction
shiga-like toxin, botulinum, cholera, diphtheria, erythrogenic toxin of Strep pyogenes
63
gram positive, branching filaments, anaerobe, not acid fast
actinomyces
64
gram positive, branching filaments, aerobe, acid fast
nocardia
65
gram positive, cocci, catalase positive
staph
66
gram positive, cocci, catalase negative
strep
67
coagulase positive staph
S. aureus
68
coagulase negative staph, novobiocin sensitive
S. epidermidis
69
coagulase negative staph, novobiocin resistant
S. saphrophyticus
70
alpha hemolytic strep, capsule, optochin sensitive
S.pneumonia
71
alpha hemolytic strep, no capsule, optochin resistant
viridans strep (S. mutans)
72
beta hemolytic strep, group A, bacitracin sensitive
S. pyogenes
73
beta hemolytic strep, group B, bacitracin resistant
S. agalactiae
74
gamma hemolytic strep, group D, growth in bile and 6.5% NaCl
enterococcus (E. faecalis)
75
gamma hemolytic strep, growth in bile, not 6.5% NaCl
nonenterococcus (S. bovis)
76
beta hemolytic bacteria
S. aureus, Strep pyogenes, Strep agalactiae, Listeria monocytogenes
77
S. aureus
gram + cocci, protein A binds Fc-IgG inhibiting complement fixation; forms fibrin clot around self-->can lead to abscess
78
S. aureus spread
traumatic wound-->leaking CSF-->meninges
79
MRSA
resistant to beta lactams because of altered penicillin-binding protein
80
staph. epidermidis
catalase +, coagulase -, novobiocin sensitive; associated with ventriculoperitoneal shunts; produces adherent biofilms (extracellular polysaccharide matrix)
81
empiric treatment for staph. epidermidis
vancomycin
82
strep. pneumonia
most common cause of meningitis, otitis media, pneumonia, sinusitis; lancet-shaped , gram + diplococci, encapsulated, IgA protease; optochin sensitive, lysed by bile
83
strep pneumonia spread
middle ear-->contiguous tissue-->meninges; primary lung focus-->blood-->meninges
84
viridans group strep
alpha hemolytic, resistant to optochin; can produce extracellular polysaccharides (dextrans)-->facilitate strep adherens to fibrin (must have pre-existing endothelial damage); not lysed by bile
85
strep pyogenes
beta hemolytic, bacitracin sensitive. Ab to M protein enhance host defenses-->can give rheumatic fever
86
what detects recent strep. pyogenes infection?
ASO titer
87
strep. agalactiae
bacitracin resistant, beta hemolytic; produces CAMP factor (enlarges area of hemolysis formed by S. aureus). Hippurate test positive
88
CAMP test
detects incomplete hemolysin
89
enterococci (group D strep)
normal colonic flora; cause UTI, biliary tract infections, subacute endocarditis; can grow in 6.5% NaCl and bile
90
strep bovis (group D strep)
can cause bacteremia and subacute endocarditis in colon cancer pts
91
corynebacterium diphtheriae
exotoxin encoded by bate prophage; inhibits protein synthesis via ADP-ribosylation of EF-2; pseudomembranous pharyngitis with lymphadenopathy, myocarditis, arrhythmia
92
gram + rods with metachromatic granules and Elek's test for toxin
corynebacterium diphtheriae
93
toxoid vaccine
prevents diphtheria; IgG against exotoxin B subunit
94
black colonies on cystine-tellurite agar
corynebacterium diphtheria
95
have dipicolinic aicd in their core
spores
96
gram positive, spore-forming, obligate anaerobic bacilli
clostridia
97
C. tetani
toxin (and botulinum toxin) is a protease that cleaves releasing proteins for neurotransmitters; blocks glycine and GABA release; immunized mother can pass IgG to fetus to provide passive immunity
98
C. tetani spread
wound-->motor neuron axons-->spinal cord
99
C. botulinum
heat-labile toxin that inhibits ACh release; bilateral descending muscle weakness, diplopia, dysphagia, dysphonia
100
C. perfringes
produces alpha toxin (lecithinase); loss of cell membrane integrity, can cause diarrhea from meat
101
C. difficile
AB toxin (B destroys cytoskeletal structure)-->pseudomembranous colitis; secondary to clindamycin or ampicillin
102
C. difficile treatment
metronidazole or vanco
103
neonatal tetanus
usually results from C. tetani colonization of umbilical stump
104
anthrax
gram + spore-forming rod; only bacterium with polypeptide capsule (contains D-glutamate)
105
baccilus cereus
food poisoning (reheated rice syndrome); nausea and vomiting caused by cereulide
106
listeria monocytogens
gram +, beta hemolytic, blue-green transluscent colonies, intracellular growth; transmission from unpasteurized milk or vaginal
107
forms actin rockets, tumbling motility
listeria monocytogens
108
listeria monocytogens diseases
spontaneous abortion, granulomatosis infantiseptica, neonatal meningitis, mild gastroenteritis. Treat neonates and immunocompromised with ampicillin
109
actinomyces
gram + rod anaerobe, not acid fast; oral/facial abscesses; treat with penicillin
110
nocardia
gram+ aerobe, acid fast; pulmonary and cutaneous infections; treat with sulfonamides
111
mycobacteria TB
phagocytosed by alveolar macrophages and sulfatide virulence factor allows for intracellular bacterial proliferation; never treated as monotherapy due to resistance
112
TB immune reaction
TH1-mediated; primary: CD4+ TH1, lymphocytes, macrophages
113
M. avium
causes disseminated non-TB disease in AIDS. prophylaxis with azithromycin
114
cord factor
in virulent TB strains; inhibits macrophage stimulation and induces release of TNF alpha
115
M. TB spread
primary lung focus-->blood-->meninges
116
acid fast bacillus that likes cool temperatures
mycobacterium leprae
117
lepromatous form
diffuse over skin; low cell-mediated immunity with TH2 response; functionally defective macrophages
118
tuberculoid form
a few hairless skin plaques; high cell-mediated immunity with largely CD4+ TH1 response; lepromin skin test is positive
119
tuberculoid form treatment
dapsone and rifampin for 6 months
120
lepromatous form treatment
dapsone, rifampin, clofazimine for 2-5 years
121
gram -, oxidase +, comma shaped, grows in 42 degrees
campylobacter jejuni
122
gram -, oxidase +, comma shaped, grows in alkaline media
vibrio chlerae
123
gram - diplococci, maltose fermenter
N. meningitidis
124
gram - diplococci, maltose nonfermenter
N. gonorrhoeae
125
gram - rod, lactose nonfermenter, oxidase -
shigella, salmonella, proteus
126
gram - rod, lactose nonfermenter, oxidase +
pseudomonas, H. pylori
127
lactose-fermenting enteric bacteria
klebsiella, e. coli, enterobacter, citrobacter, serratia
128
produces beta galactosidase, which breaks down lactose into glucose and galactose
E. coli
