Lec 2 Intro to ID 2 Rybakov Flashcards
gram positive bacteria appear _____ under a microscope
a. green
b. red/pink
c. purple
d. blue
c. purple (due to thick peptidoglycan wall)
gram-neg bacteria appears _____ under a microscope
a. green
b. red/pink
c. purple
d. blue
b. red/pink
gram-positive
cocci
anaerobic (2 answers)
-peptococcus
-peptostreptococcus
gram-positive
cocci
aerobic
catalase (+)
coagulase (+)
a. Staph aureus
b. CoNS (staph epidermis)
c. Streptococcus pneumoniae
d. Enterococcus faecium
a. Staph aureus
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)
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
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)
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
aerobic cocci clusters is considered _______ positive
catalase
aerobic cocci pairs/chains is considered _______ negative
catalase
gram positive aerobic cocci clusters
a. catalase +
b. catalase -
c. anaerobic
a. catalase +
gram positive aerobic cocci pairs/chains
a. catalase +
b. catalase -
c. anaerobic
b. catalase -
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
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
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
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
staphylococcus aureus is ALWAYS _______ _______
a. catalase negative
b. coagulase positive
c. coagulase negative
b. coagulase positive
group A
a. streptococcus pyogenes
b. streptococcus agalactiae
a. streptococcus pyogenes
group B
a. streptococcus pyogenes
b. streptococcus agalactiae
b. streptococcus agalactiae
for gram-positive, most medically important pathogens are
a. cocci
b. bacilli
c. coccobacilli
a. cocci
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)
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
gram negative
aerobic
cocci (2 answers)
a. Neisseria spp
b. Moraxella catarrhalis
c. Haemophilus spp
d. Prevotella
a. Neisseria spp
b. Moraxella catarrhalis
gram negative
aerobic
coccobacilli
a. Neisseria spp
b. Moraxella catarrhalis
c. Haemophilus spp
d. Prevotella
c. Haemophilus spp
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
- Cmax/MIC
- AUC/MIC
- 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
- inc dose, same interval
- same dose, shorter interval
- continuous infusion (stability issues; need IV)
- 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
T
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
