MRSA

Question 1

Mechanism: mecA gene –> altered PBP with decreased affinity for beta-lactams

Answer 1

MRSA

Question 2

MRSA is also clinically resistant to which 3 things?

Answer 2

Cephalosporins, carbapenems, and Beta-lactamase inhibitor combinations

Question 3

Usually the antibiotic of choice for MRSA

Answer 3

Vancomycin

Question 4

Often first detected as clusters of abscesses or “spider bites”

Answer 4

MRSA

Question 5

The most common identifiable cause of skin and soft-tissue infections among patients presenting to emergency departments in 11 U.S. cities

Answer 5

MRSA

Question 6

Community acquired MRSA is genetically distinct from

Answer 6

Hospital Acquired MRSA

Question 7

Carriage less common in nares, so nasal screening may fail to detect

Answer 7

Community acquired MRSA

Question 8

Can be used to treat CA-MRSA skin and soft tissue infections

Answer 8

Incision and drainage

Question 9

To break the chain of MRSA transmission within families, we want to give every member

Answer 9

Chlorhexidine Gluconate (CHG)

Question 10

Multiplication of organisms in the body of the host

–Usually involves invasion of tissue

Answer 10

Infection

Question 11

Infection is usually accompanied by a measurable host response such as

Answer 11

Inflammation, antibody production, and Cell-mediated immunity

Question 12

Multiplication of an organism at a body site or sites without evidence of infection

–May or may not be a precursor of infection

Answer 12

Colonization

Question 13

If an infection develops, it is usually from bacteria that

Answer 13

Colonize patients

Question 14

Bacteria that colonize patients can be transmitted from one patient to another by the hands of

Answer 14

Healthcare workers

Question 15

What are the three most common anatomic sites for MRSA?

Answer 15

Nares, Rectum, and Axilla

Question 16

“Pseudomonicacid” –derived from culture supernatants of Pseudomonas fluorescens

-A topical antibiotic

Answer 16

Mupirocin

Question 17

Bacteriostatic, but activity dependent on pH and inoculum size

–may be bactericidal at low pH (skin pH <5.5)

Answer 17

Mupirocin

Question 18

Binds to isoleucyltRNA synthetase( ile S) disrupts protein synthesis

Answer 18

Mupirocin

Question 19

Mupirocin has been shown to decrease carriage of S. aureus in

Answer 19

Nasal cavities (and on hands)

Question 20

Intrinsic resistance (gram negatives) from inability to bind to tRNA synthetase, not from altered drug transport or increased drug destruction

Answer 20

Mupirocin resistance

Question 21

A low-level mupirocin resistance is due to a

Answer 21

Point mutation in ileS

Question 22

A high-level mupirocin resistance is due to the acquisition of a

Answer 22

Plasmid containing a novel ileS gene

Question 23

Transmissible between SA and coag neg Staph, but not to enterococci

Answer 23

High-level Mupirocin resistance

Question 24

been classified as being of “dubious” clinical significance

Answer 24

Low-level resistance

Question 25

“MRSA strains with Mup-R were often more susceptible to other antimicrobial agents, such as

Answer 25

TCN and TMP-SMX

Question 26

What is the fastest form of MRSA screening?

Answer 26

Xpert MRSA/GeneXpert

Question 27

The gold standard for MRSA detection

Answer 27

Broth enrichment

Question 28

Anaerobic spore-forming bacillus

-Causes pseudomembranous colitis, toxic mega colon, sepsis, and death

Answer 28

Clostridium difficile

Question 29

Fecal-oral transmission through contaminated environment and hands of healthcare personnel

Answer 29

Clostridium difficile

Question 30

Antimicrobial exposure is a major risk factor for

Answer 30

Clostridium difficile

Question 31

What is the only antimicrobial that KPC producing K. pneumoniae (CRKP) is susceptible (S) to?

Answer 31

Tigecycline