Lec 2 Intro to ID 2 Rybakov Flashcards by Rehman Hameed

gram positive bacteria appear _____ under a microscope

a. green
b. red/pink
c. purple
d. blue

c. purple (due to thick peptidoglycan wall)

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gram-neg bacteria appears _____ under a microscope

a. green
b. red/pink
c. purple
d. blue

b. red/pink

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gram-positive
cocci
anaerobic (2 answers)

-peptococcus
-peptostreptococcus

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gram-positive
cocci
aerobic
catalase (+)
coagulase (+)

a. Staph aureus
b. CoNS (staph epidermis)
c. Streptococcus pneumoniae
d. Enterococcus faecium

a. Staph aureus

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gram-positive
cocci
aerobic
catalase (+)
coagulase (-)

a. Staph aureus
b. CoNS (staph epidermis)
c. Streptococcus pneumoniae
d. Enterococcus faecium

b. CoNS (staph epidermis)

(CoNS stands for coagulase negative staph epidermis)

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gram-positive
cocci
anaerobic
catalase (-)
alpha hemolysis (2 answers)

a. streptococcus pneumoniae
b. vividans streptococci
c. streptococcus pyogenes
d. streptococcus aglactieae
e. enterococcus faecium
f. enterococcus faecalis

a. streptococcus pneumoniae
b. vividans streptococci

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gram-positive
cocci
anaerobic
catalase (-)
beta hemolysis (2 answers)

a. streptococcus pneumoniae
b. vividans streptococci
c. streptococcus pyogenes
d. streptococcus agalactiae
e. enterococcus faecium
f. enterococcus faecalis

c. streptococcus pyogenes (group A)
d. streptococcus agalactiae (group B)

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gram-positive
cocci
anaerobic
catalase (-)
gamma hemolysis (2 answers)

a. streptococcus pneumoniae
b. vividans streptococci
c. streptococcus pyogenes
d. streptococcus aglactieae
e. enterococcus faecium
f. enterococcus faecalis

e. enterococcus faecium
f. enterococcus faecalis

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aerobic cocci clusters is considered _______ positive

catalase

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aerobic cocci pairs/chains is considered _______ negative

catalase

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gram positive aerobic cocci clusters

a. catalase +
b. catalase -
c. anaerobic

a. catalase +

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gram positive aerobic cocci pairs/chains

a. catalase +
b. catalase -
c. anaerobic

b. catalase -

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gram positive
bacilli
anaerobic
spore forming (2 answers)

a. clostridium spp
b. clostridioides difficile
c. cutibacterium
d. actinomyces
e. bacillus spp
f. corynebacterium
g. lactobacillus spp
h. listeria monocytogenes

a. clostridium spp
b. clostridioides difficile

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gram positive
bacilli
anaerobic
non-spore forming (2 answers)

a. clostridium spp
b. clostridioides difficile
c. cutibacterium
d. actinomyces
e. bacillus spp
f. corynebacterium
g. lactobacillus spp
h. listeria monocytogenes

c. cutibacterium
d. actinomyces

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gram positive
bacilli
aerobic
spore forming (1 answer)

a. clostridium spp
b. clostridioides difficile
c. cutibacterium
d. actinomyces
e. bacillus spp
f. corynebacterium
g. lactobacillus spp
h. listeria monocytogenes

e. bacillus spp

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gram positive
bacilli
aerobic
non-spore forming (3 answers)

a. clostridium spp
b. clostridioides difficile
c. cutibacterium
d. actinomyces
e. bacillus spp
f. corynebacterium
g. lactobacillus spp
h. listeria monocytogenes

f. corynebacterium
g. lactobacillus spp
h. listeria monocytogenes

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staphylococcus aureus is ALWAYS _______ _______

a. catalase negative
b. coagulase positive
c. coagulase negative

b. coagulase positive

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group A

a. streptococcus pyogenes
b. streptococcus agalactiae

a. streptococcus pyogenes

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group B

a. streptococcus pyogenes
b. streptococcus agalactiae

b. streptococcus agalactiae

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for gram-positive, most medically important pathogens are

a. cocci
b. bacilli
c. coccobacilli

a. cocci

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which of the following is FALSE about gram-positive bacteria? SELECT ALL THAT APPLY

a. usually cocci rather than bacilli
b. staphylococcus forms pairs/chains
c. streptococci and enterococci forms clusters
d. catalase test separates staphylococci from streptococci
e. gamma-hemolytic organisms appear in GI tract

b. staphylococcus forms pairs/chains
c. streptococci and enterococci forms clusters

(b. forms clusters, c. appears in pairs/chains)

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Patient JR has Gram-positive cocci growing in the blood. They don’t have a full identification but tell you the organism is catalase positive, coagulase positive. Which of the following organisms could be growing in JR’s blood?

a) Staphylococcus aureus
b) Staphylococcus epidermidis
c) Streptococcus pyogenes
d) Enterococcus faecalis

a) Staphylococcus aureus

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gram negative
aerobic
cocci (2 answers)

a. Neisseria spp
b. Moraxella catarrhalis
c. Haemophilus spp
d. Prevotella

a. Neisseria spp
b. Moraxella catarrhalis

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gram negative
aerobic
coccobacilli

a. Neisseria spp
b. Moraxella catarrhalis
c. Haemophilus spp
d. Prevotella

c. Haemophilus spp

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gram negative bacilli anaerobic (4 answers) a. Campylobacter b. Bacteroides c. Helicobacter d. Acinetobacter spp e. Fusobacterium f. Prevotella g. Veillonella spp

b. Bacteroides e. Fusobacterium f. Prevotella g. Veillonella spp

are fastidious gram neg bacilli aerobic or anaerobic?

aerobic

gram neg aerobic bacilli enterobacterales lactose fermenters (oxidase neg) what bugs are in this class? (acronym)

CEEK acronym citrobacter spp enterobacter spp e. coli klebsiella spp

are lactose fermenters oxidase positive or negative?

negative

Morganella morganii Proteus spp Providencia spp Salmonella spp Serratia marcescens Shigella spp a. aerobic bacilli, enterobacterales, lactose fermenters b. aerobic bacilli, enterobacterales, non-lactose fermenters c. anaerobic cocci d. anaerobic bacilli e. fastidious

b. aerobic bacilli, enterobacterales, non-lactose fermenters

gram neg aerobic bacilli non-enterobacterales lactose fermenters (3 answers) a. aeromonas hydrophila b. pasteurella multocida c. vibrio cholerae d. pseudomonas spp e. acinetobacter spp f. alcaligenes spp g. burkholderia cepacia h. stenotrophomonas i. campylobacter j. helicobacter k. bartonella l. HACEK organisms

a. aeromonas hydrophila b. pasteurella multocida c. vibrio cholerae

gram neg aerobic bacilli non-enterobacterales non-lactose fermenters (5 answers) a. aeromonas hydrophila b. pasteurella multocida c. vibrio cholerae d. pseudomonas spp e. acinetobacter spp f. alcaligenes spp g. burkholderia cepacia h. stenotrophomonas i. campylobacter j. helicobacter k. bartonella l. HACEK organisms

d. pseudomonas spp e. acinetobacter spp f. alcaligenes spp g. burkholderia cepacia h. stenotrophomonas

gram neg aerobic bacilli non-enterobacterales fastidious (4 answers) a. aeromonas hydrophila b. pasteurella multocida c. vibrio cholerae d. pseudomonas spp e. acinetobacter spp f. alcaligenes spp g. burkholderia cepacia h. stenotrophomonas i. campylobacter j. helicobacter k. bartonella l. HACEK organisms

i. campylobacter j. helicobacter k. bartonella l. HACEK organisms

chlamydia, legionella, mycoplasma... a. atypical b. spirochetes c. fastidious

a. atypical

treponema pallidium borellia burgdorferi a. atypical b. spirochetes c. fastidious

b. spirochetes

campylobacter helicobacter bartonella HACEK organisms a. atypical b. spirochetes c. fastidious

c. fastidious

are gram-negative cocci or bacilli more common?

bacilli

Patient ZE has Gram-negative rods growing in the blood. They don’t have a full identification but tell you the organism is a non-enteric non-lactose fermenter. Which of the following organisms could be growing in JR’s blood? a) Pseudomonas aeruginosa b) Citrobacter freundii c) Morganella morganii d) Aeromonas hydrophila

a) Pseudomonas aeruginosa (b. is enteric lactose fermenter, c. is enteric non-lactose fermenter, d. is lactose fermenter)

-Acts as selective barrier -Certain drugs must pass through to reach target site a. cytoplasmic membrane b. peptidoglycan layer (cell wall) c. outer memb (gram-neg) d. periplasmic space

a. cytoplasmic membrane

-Permeability barrier for large molecules -PBPs: proteins essential for cell-wall synthesis a. cytoplasmic membrane b. peptidoglycan layer (cell wall) c. outer memb (gram-neg) d. periplasmic space

b. peptidoglycan layer (cell wall)

-lipopolysaccharides (LPS) -porins a. cytoplasmic membrane b. peptidoglycan layer (cell wall) c. outer memb (gram-neg) d. periplasmic space

c. outer memb (gram-neg)

Vital for bacterial protein secretion, folding, quality control; acts as reservoir for virulence factors a. cytoplasmic membrane b. peptidoglycan layer (cell wall) c. outer memb (gram-neg) d. periplasmic space

d. periplasmic space

transferable between organisms a. plasmid b. transposons c. conjugation

a. plasmid

move from plasmid to chromosomes or vice versa a. plasmid b. transposons c. conjugation

b. transposons

most common method of acquired resistance a. plasmid b. transposons c. phages d. conjugation e. transduction f. transformation

d. conjugation

Which of the following describes the difference between Gram-positive and Gram-neg bacteria? a) Gram-positive have a thin cell wall; Gram-negative have a thick cell wall b) Gram-positive have a thick cell wall; Gram-negative have a thin cell wall c) Gram-positive have porin channels; Gram-negative lack porin channels d) Gram-positive have PBP; Gram-negative lack PBP

b) Gram-positive have a thick cell wall; Gram-negative have a thin cell wall

enzyme example of extended-spectrum beta-lactamases (ESBLs) a. CTX-M-15 b. KPC-1 c. NDM-1 d. Amp-C e. OXA-48

a. CTX-M-15

enzyme example of serine carbapenemases a. CTX-M-15 b. KPC-1 c. NDM-1 d. Amp-C e. OXA-48

b. KPC-1

enzyme example of metallo-beta-lactamases a. CTX-M-15 b. KPC-1 c. NDM-1 d. Amp-C e. OXA-48

c. NDM-1

enzyme example of cephalosporinases a. CTX-M-15 b. KPC-1 c. NDM-1 d. Amp-C e. OXA-48

d. Amp-C

OXA-type enzyme example a. CTX-M-15 b. KPC-1 c. NDM-1 d. Amp-C e. OXA-48

e. OXA-48 (obviously)

tx of choice for ESBL infections

carbapenems

zosyn is a tx option for ESBL infection in ______ source only

urinary

Hydrolyze penicillin; produced primarily by Enterobacterales a. narrow-spec b-lactamases b. extended-spec b-lactamases (ESBL) c. serine carbapenemases d. metallo-b-lactamases e. cephalosporinases f. OXA-type

a. narrow-spec b-lactamases

Hydrolyze narrow & extended spectrum-β-lactam antibiotics a. narrow-spec b-lactamases b. extended-spec b-lactamases (ESBLs) c. serine carbapenemases d. metallo-b-lactamases e. cephalosporinases f. OXA-type

b. ESBLs

Hydrolyze carbapenems (3 answers) a. narrow-spec b-lactamases b. extended-spec b-lactamases (ESBL) c. serine carbapenemases d. metallo-b-lactamases e. cephalosporinases f. OXA-type

c. serine carbapenemases d. metallo-b-lactamases f. OXA-type

inducible a. narrow-spec b-lactamases b. extended-spec b-lactamases (ESBL) c. serine carbapenemases d. metallo-b-lactamases e. cephalosporinases f. OXA-type

e. cephalosporinases

Hydrolyze oxacillin, oxyimino β-lactams, and carbapenems a. narrow-spec b-lactamases b. extended-spec b-lactamases (ESBL) c. serine carbapenemases d. metallo-b-lactamases e. cephalosporinases f. OXA-type

f. OXA-type

ambler class A (3 answers) a. narrow-spec b-lactamases b. extended-spec b-lactamases (ESBL) c. serine carbapenemases d. metallo-b-lactamases e. cephalosporinases f. OXA-type

a. narrow-spec b-lactamases b. extended-spec b-lactamases (ESBL) c. serine carbapenemases

Ambler class B a. narrow-spec b-lactamases b. extended-spec b-lactamases (ESBL) c. serine carbapenemases d. metallo-b-lactamases e. cephalosporinases f. OXA-type

d. metallo-b-lactamases

Ambler class C a. narrow-spec b-lactamases b. extended-spec b-lactamases (ESBL) c. serine carbapenemases d. metallo-b-lactamases e. cephalosporinases f. OXA-type

e. cephalosporinases

Ambler class D a. narrow-spec b-lactamases b. extended-spec b-lactamases (ESBL) c. serine carbapenemases d. metallo-b-lactamases e. cephalosporinases f. OXA-type

f. OXA-type

the CTX-M enzyme is most prevalent in all of the following EXCEPT: a. E. coli b. Klebsiella pneumoniae/oxytoca c. Acinetobacter spp d. Proteus mirabilis

c. Acinetobacter spp

Most frequent cause of of Carbapenem-resistant Enterobacterales (CRE) in the USA a. narrow-spec b-lactamases b. extended-spec b-lactamases (ESBL) c. serine carbapenemases d. metallo-b-lactamases e. cephalosporinases f. OXA-type

c. serine carbapenemases (the slide doesn't have the serine; resistance to whole beta-lactam class)

KPC (Klebsiella pneumoniae carbapenemase) is found in which bacteria? (6 of them)

K. pneumoniae K. oxytoca E. coli E. cloacae E. aerogenes P. mirabilis

metallo-beta-lactamase enzyme example

NDM (New Delhi MBL)

tx option if NDM enzyme is present (2 listed)

cefiderocol (trojan horse) aztreonam + ceftazidime/avibactam (limited options)

NDM resistance is present in all of the following EXCEPT: a. Enterobacterales b. Morganella morganii c. Pseudomonas aeruginoas d. Acinetobacter spp

b. Morganella morganii

OXA-type resistant is primarily found in which 2 bacteria? (underlined)

Acinetobacter baumannii Pseudomonas aeruginosa

tx option if OXA-48 enzyme is present (2 listed)

cefiderocol sulbactam/durlobactam

T or F: carbapenem-resistant Enterobacterales (CRE) means carbapenemases are present

F (can be CRE through efflux pumps, porins)

JM is a 45 YOM admitted with fever, chills, urinary frequency and urgency. Blood cultures are collected and 12 hour after admission rapid diagnostic testing identifies E.coli, CTX-M (+) in 4/4 bottles. What type of antibiotic resistance is present? a. Non-CP CRE b. ESBL c. NDM d. KPC

b. ESBL

JM is a 45 YOM admitted with fever, chills, urinary frequency and urgency. Blood cultures are collected and 12 hour after admission rapid diagnostic testing identifies E.coli, CTX-M (+) in 4/4 bottles. What is their recommended tx option? a) Meropenem b) Meropenem/vaborbactam c) Aztreonam + Ceftazidime/avibactam d) Piperacillin/tazobactam

a) Meropenem (CTX-M is present in ESBL resistance. Carbapenem is tx option)

AmpC most important resistance mechanism

inducible via chromosomally encoded AmpC genes

AmpC is found in which bacteria? (acronym)

HECK-YES Ma'am Hafnia alvei Enterobacter cloacae Citrobacter freundii Klebsiella aerogenes Yersinia enterocolitica Serratia marcescens Morganella morganii Aeromonas hydrophila

AmpC induction mechanism: Gene for beta-lactamase production is _______ -> inducer -> gene _______ -> inc beta-lactamase production Remove inducer -> gene _______ -> beta-lactamase production back to low level Genetic mutation -> gene _______ -> _______ _______ -> high level beta-lactamase production continuously

repressed; derepressed repressed derepressed; stable derepression

weak AmpC inducer bolded on slide a. Penicillin G b. Cefazolin c. Aztreonam d. Ceftriaxone

d. Ceftriaxone

1st line tx for stably depressed mutants a. Ceftriaxone b. Cefepime c. Cephalexin d. Levofloxacin

b. Cefepime

JH is a 65 YOM admitted with pyelonephritis (infection in the kidney) and started on IV ceftriaxone. However, he soon develops a fever and becomes hypotensive. Blood cultures are taken and result for E. cloacae. What could explain his sudden decompensation? a) E. cloacae harbors an ESBL gene and this was induced with ceftriaxone tx b) E. cloacae harbors a KPC gene and this was induced with ceftriaxone tx c) E. cloacae harbors an AmpC gene and this was induced with ceftriaxone tx d) E. cloacae harbors a NDM gene and this was induced with ceftriaxone tx

c) E. cloacae harbors an AmpC gene and this was induced with ceftriaxone tx

JH is a 65 YOM admitted with pyelonephritis (infection in the kidney) and started on IV ceftriaxone. However, he soon develops a fever and becomes hypotensive. Blood cultures are taken and result for E. cloacae. What antibiotic change would you recommend? a) Switch to Piperacillin/tazobactam b) Switch to Cefepime c) Switch to Ceftazidime d) Switch to Aztreonam

b) Switch to Cefepime (tx for stably depressed mutants from AmpC induction)

mechanism of vancomycin resistance in Enterococci species a. altered target site: PBPs b. altered target site: cell wall precursor c. altered target site: ribosomal target d. altered target site: DNA gyrase/topo IV

b. altered target site: cell wall precursor

most common method of aminoglycoside resistance

aminoglycoside-modifying enzymes

3 mechanisms for aminoglycoside-modifying enzymes

acetylation nucleotidylation phosphorylation

which of the following is NOT a mechanism for aminoglycoside-modifying enzymes? a. adenylation b. acetylation c. phosphorylation d. nucleotidylation

a. adenylation

two genes for vanc resistance

VanA and VanB

What is the mechanism of Staphylococcus aureus resistance to beta-lactams? a) mecA gene b) VanA gene c) ermB gene d) KPC gene

a) mecA gene (methicillin resistant staph aureus = MRSA)

MRSA resistance is due to expression of which gene? What does this gene encode for?

mecA; encodes for PBP2A

efflux pumps are an Important resistance mechanism for _____ _____ against carbapenems & _____ _____ against macrolide antibiotics

Pseudomonas aeruginosa Streptococcus pneumoniae

mutations that result in the loss of porins is most commonly seen with _______ and carbapenem-resistant _______ _______

Enterobacterales Pseudomonas aeruginosa

which antibiotic class includes ADP-ribosylation as a resistance mechanism? a. beta-lactams b. glycopeptides c. macrolides d. fluoroquinolones e. rifamycins

e. rifamycins

AUC definition a. Highest drug concentration b. Overall drug exposure over a certain time c. Minimum inhibitory concentrations

b. Overall drug exposure over a certain time

3 main PK/PD indices

1. Cmax/MIC 2. AUC/MIC 3. fT>MIC

Continued growth inhibition for a variable period after concentration at site of infection has decreased below MIC a. Cmax b. PAE c. MIC d. AUC

b. PAE (post antibiotic effect)

Time that free drug concentrations remain above MIC is known as ______ which correlates with clinical and microbiological outcomes

ft>MIC

fT>MIC penicillin: ___% fT>MIC cephalosporin: ___-___% fT>MIC carbapenem: ___%

50% 60-70% 40%

4 strategies to maximize fT/MIC of beta-lactams

1. inc dose, same interval 2. same dose, shorter interval 3. continuous infusion (stability issues; need IV) 4. prolonged infusions (3-4 hours, longer T>MIC)

PD target for Vancomycin

AUC0-24/MIC

goal AUC/MIC for vancomycin

400-600

Which of the following describes the PK/PD parameters of meropenem? a) Time-dependent antibiotic; fT>MIC 40% of the dosing interval b) Concentration dependent antibiotic; fAUC/MIC c) Time-dependent antibiotic; fT>MIC 80% of the dosing interval d) Concentration dependent antibiotic; Cmax/MIC

a) Time-dependent antibiotic; fT>MIC 40% of the dosing interval

T or F: all beta-lactam antibiotics (penicillin, cephalosporin, carbapenem, monobactam) are time-dependent

which of the following are time-dependent? SELECT ALL THAT APPLY a. aminoglycosides b. beta-lactams c. daptomycin d. fluoroquinolones e. vancomycin

b. beta-lactams e. vancomycin

which of the following are concentration-dependent? SELECT ALL THAT APPLY a. aminoglycosides b. beta-lactams c. daptomycin d. fluoroquinolones e. vancomycin

a. aminoglycosides c. daptomycin d. fluoroquinolones

is daptomycin time or concentration dependent?

concentration

aminoglycosides 2 predictive PK/PD parameters

Peak/MIC AUC/MIC

beta-lactams predictive PK parameter a. T>MIC b. Peak/MIC c. AUC/MIC

a. T>MIC

fluroquinolones and vancomycin predictive PK parameter a. T>MIC b. Peak/MIC c. AUC0-24/MIC

c. AUC0-24/MIC