Resistance & Detection

What chromogenic method is used for β-lactamase detection?

nitrocefin

Which β-lactamase detection method gives a pink positive result?

nitrocefin

Which β-lactamase detection method gives a yellow positive result?

acidic

Which β-lactamase detection method gives no color change when positive?

iodometric

Which β-lactamase detection method stays colorless when positive?

iodometric

β-lactamase enzyme detection is performed on isolates of which gram-positive cocci genus?

Staphylococcus

β-lactamase enzyme detection is performed on which Neisseria species listed?

gonorrhoeae

β-lactamase enzyme detection is performed on which catarrhalis species?

M. catarrhalis

β-lactamase enzyme detection is performed on which fastidious respiratory genus?

Haemophilus

A positive D test is reported as erythromycin resistant and clindamycin what?

resistant

A positive D test shows flattening of the clindamycin zone adjacent to what antibiotic?

erythromycin

If the D test is positive, clindamycin should be reported as what?

resistant

Inducible clindamycin resistance is associated with resistance to what nearby drug disk?

erythromycin

What zone change next to erythromycin indicates a positive D test?

flattening

Which antibiotic should not be given when the D test is positive?

clindamycin

Which gene is responsible for inducible clindamycin resistance?

erm

Which test is used for inducible clindamycin resistance?

D test

ESBL stands for what?

Extended-Spectrum β-Lactamase

ESBLs hydrolyze which broad antibiotic group listed first in the notes?

penicillins

ESBLs hydrolyze which monobactam listed in the notes?

aztreonam

ESBLs hydrolyze which β-lactam subgroup listed second in the notes?

cephalosporins

What enzyme type is abbreviated ESBL?

β-lactamase

What gene is responsible for methicillin resistance according to the notes?

mecA

Which Proteus species listed can produce ESBLs?

mirabilis

Which common organism listed can produce ESBLs and starts with E.?

Escherichia

Which common organism listed can produce ESBLs and starts with K.?

Klebsiella

Which organism group besides E. coli and Klebsiella can produce ESBLs?

Enterobacteriaceae

Which organism is the most commonly known carrier of the mecA gene?

MRSA

A larger zone with inhibitor suggests production of what enzyme?

ESBL

ESBL detection by disk diffusion uses which indicator drug paired first in the notes?

cefotaxime

ESBL detection by disk diffusion uses which indicator drug paired second in the notes?

ceftazidime

If the combined-disk zone is larger than the indicator drug alone, the organism produces what?

ESBL

What β-lactamase inhibitor is combined with indicator drugs for ESBL detection?

clavulanic acid

Which inhibitor is paired with cefotaxime or ceftazidime in combined-disk ESBL testing?

clavulanate

A positive Hodge test produces what leaf-like indentation pattern?

cloverleaf

In the Hodge test, which carbapenem disk is placed at the center of the agar?

imipenem

What enzyme activity is suggested when imipenem is hydrolyzed in the Hodge test?

carbapenemase

What gene is associated with resistance to all β-lactam antibiotics in the Hodge test notes?

blaKPC

Which carbapenemase screening test uses E. coli ATCC spread over Mueller-Hinton agar?

Hodge

Which organism lawn is used in the Hodge test background?

E. coli

Which screening test uses a cloverleaf-like indentation as the positive pattern?

Hodge

A cefoxitin 30-microgram disk predicts the presence of what gene?

mecA

At what temperature range is oxacillin MRSA testing incubated?

33-35C

How long may oxacillin MRSA testing be incubated according to the notes?

48 hours

Molecular MRSA methods detect which resistance gene?

mecA

Oxacillin testing for MRSA uses Mueller-Hinton agar with what NaCl concentration?

4%

What atmosphere is used for oxacillin MRSA testing?

ambient air

What gene is directly predicted by cefoxitin disk testing?

mecA

What oxacillin disk content is listed for MRSA detection?

6 μg

What type of method is the reference method for MRSA detection?

molecular

Which 30-microgram disk is better than oxacillin for inducing mecA expression?

cefoxitin

Which atmosphere is specified for oxacillin screen incubation?

ambient

Which disk is preferred over oxacillin for mecA induction?

cefoxitin

A change in porin channels causes decreased what?

permeability

A change in porin channels leads to decreased what according to the notes?

uptake

An increase in pumping out contents is an example of what resistance mechanism?

efflux

Enterococci are naturally resistant to what drug class in the notes?

cephalosporin

Klebsiella pneumoniae is naturally resistant to what drug in the notes?

ampicillin

What cell target alteration is listed as a resistance mechanism?

target changes

What enzymatic resistance mechanism is listed in the notes?

enzyme production

What extra-chromosomal resistance mechanism is listed in the notes?

plasmids

What genetic event is listed as a bacterial resistance mechanism besides plasmid production?

mutation

What mechanism can increase pumping out of contents?

efflux

What permeability-related resistance mechanism is listed in the notes?

reduced permeability

What type of resistance is described as natural in the notes?

intrinsic

What type of resistance is described as natural or intrinsic?

intrinsic

VanA-mediated VRE causes inducible high-level resistance to vancomycin and what related drug?

teicoplanin

VanB-mediated VRE shows variable resistance to vancomycin but susceptibility to what drug?

teicoplanin

What type of assay can detect VRE according to the notes?

PCR

Which Enterococcus species is listed as the most common vancomycin-resistant species?

faecium

Which VRE mechanism is inducible and high-level?

VanA

Which VRE mechanism remains susceptible to teicoplanin?

VanB