Prevalence of extended-spectrum β-lactamase-producing Enterobacter cloacae in the Asia-Pacific Region:: Results from the SENTRY Antimicrobial Surveillance Program, 1998 to 2001

Enterobacter cloacae strains from hospitalized patients with a range of infections were collected by 17 laboratories in the Asia-Pacific region and South Africa. Isolates for which ceftriaxone MICs were above 1 mug/ml and/or ceftazidime MICs were above 2 mug/ml, as well as 46 strains for which ceftriaxone and/or ceftazidime MICs were at or below these values, were screened for levels of extended-spectrum (beta-lactamase (ESBL) production through the use of broth microdilution for the detection of clavulanate enhancement of the activity of ceftriaxone, ceftazidime, and cefepime. Of the isolates examined, ceftriaxone and/or ceftazidime had elevated MICs for 44%, of which 36% were ESBL positive. ESBL-positive strains were commonly susceptible to piperacillin-tazobactam and more frequently resistant to several other antimicrobials studied. A cefepime MIC above 0.25 mug/ml had the highest sensitivity (100%) and specificity (74%) for predicting the presence of an ESBL.