TABLE 2

MICs of evolved TEM alleles

Isolate no.
DrugaClinical MICbpACSE3TEM11234567a7b89
AMC322>4096>40964096409640964096>4096>40964096>40964096
PIP1282>20482048204820482048204820484096102420482048
TZP1281256161664321283264323232
TIC1284>4096>4096>4096>4096>4096>4096>4096>4096>40962048>4096
TIM128451225612812812825612812864128128
CEF32410245125121024512512642566464256
CXM32816512512102410241024321286432512
(CRO)640.0630.2551212864128643232163264
(CTX)640.1250.1255122565122565123232163232
(CAZ)320.2511286464645122048204851220482048
FEP320.0630.516888832164648
(ATM)320.1250.53264646412851210241281024512
  • The MICs of the antibiotic in which the lines were first selected appear italic.

  • a Abbreviations for (β-lactams are the following: AMC, ampicillin; PIP, pipericillin; TZP, pipericillin and tazobactam (8:1); TIC, ticarcillin; TIM, ticarcillin and clavulanate; CEF, cephalothin; CXM, cefuroxime; CRO, ceftriaxone; CTX, cefotaxime; CAZ, ceftazadime; FEP, cefepime; ATM, aztreonam. The “extended-spectrum” drugs used for selection are in parentheses.

  • b The indicated MICs are the NCCLS breakpoints for resistance (National Committee for Clinical Laboratory Standards 1999).