M.R.S.A

community-

phenotype

Methicillin-resistant S. aureus; clindamycin, trimethoprim/sulfamethoxazole and gentamicin sensitive

M.R.S.A

hospital-

associated

Methicillin-resistant S. aureus, clindamycin, trimethoprim/sulfamethoxazole and gentamicin: vancomycin sensitve

V.I.S.A

S. aureus with intermediate susceptibility to vancomycin. Confirmatory test are required

V.R.S.A

Vancomycin-resistant S. aureus. Confirmatory test are required

Enterococcus

A.S.E.

Ampicillin-sensitive Enterococcus

A.R.E

Ampicillin-resistant and vancomycin-sensitive Enterococcus

V.R.E.

Vancomycin-resistant Enterococcus

Streptococcus

P.S.S.

Penicillin-sensitive Streptococcus

P.I.S

Streptococcus with intermediate susceptibility to penicillin; ceftriaxone and vancomycin sensitive

P.R.S

Penicillin-resistant Streptococcus; ceftriaxone and vancomycin sensitive

C.R.S

Ceftriaxone-resistant Streptococcus, vancomycin-sensitive

Enterobacteriaceae

Pansensitive

EB

Pansensitive enterobacteria (K. pneumoniae can be naturally resistant to ampicillin)

Penicillinase-

producing EB

Penicillinase-producing enterobacteria:

Low level penicillinase: resistant to ampicillin, piperacillin, ampicillin-sulbactam, first and second generation cephalosporins

High level penicillinase: resistant to ampicillin, piperacillin, ampicillin-sulbactam, piperacilli-tazobactam, first and second generation cephalosporins

AmpC EB

AmpC positive Enterobacteriaceae (resistant to first, second and third generatrion cephalosporins and cefoxitin-resistant)

ESBL

producing EB

Extended-spectrum beta-lactamase-producing Enterobacteriaceae (resistant to first, second, third and fourth generation cephalosporins, resistant to aztreonam, can be cefoxitin-resistant or cefoxitin-sensitive)

CP-EB

Carbapenemase-producing Enterobacteriaceae (resistant to carbapenems: three or more carbapenems, including ertapenem, can be ESBL producing EB). Confirmatory test are required

MDR-EB

Multidrug resistance Enterobacteriaceae expressing combined mechanisms of resistance (efflux bomb, porins, etc.) antibiogram interpretative reading by infectologist is required

Nonfermenting

Gram-negative

Bacilli

Pansensitive NFGNB

Pansensitive nonfermenting Gram-negative Bacilli (intrisic resistance to first, second and third generation cephalosporins can exist)

AmpC

NFGNB

Non-fermenting microorganisms, resistant to first, second and third generation cephalosporins, resistant to cefoxitin, fourth generation cephalosporins-sensitive (cefepime-sensitive)

CP-NFGNB

Carbapenemase-producing nonfermenting Gram-negative Bacilli: resistant to three or more carbapenems. Confirmatory test are required