Details for BIL Poster TEM ENBAER ESBL ICAAC 2006


Background: Treatment options for infections with Extended spectrum b-lactamase (ESBL) producing Enterobacter aerogenes are limited because many b-lactam antibiotica are hydrolysed by ESBLs and because ESBL-producing bacteria are often resistant to other classes of antibiotics. We performed pulsed field gel electrophoresis (PFGE), susceptibility testing for temocillin, cefepime and meropenem and detection and ESBL-characterisation on ESBL-producing E. aerogenes strains.

Methods: On 150 consecutive E. aerogenes strains, collected in 2005 in 5 Belgian hospitals, we performed ESBL-detection by double disk synergy test, ESBL E-test (AB Biodisk,) and PCR for the presence of blaTEM, blaSHV and blaCTX-M genes.

PFGE analysis after XBA1 restriction was performed on the Genepath system (Bio-Rad). For ESBL-producing strains, minimal inhibitory concentrations (MICs) were determined for temocillin with broth microdilution and for cefepime and meropenem with E-test (AB Biodisk).

Results: ESBL-production was detected in 62 (41.3%) strains. Of these, 60 (96.8%) were positive for TEM-24, 1 (1.6%) for TEM-52 and 1 (1.6%) for SHV 4. PFGE analysis revealed two major clones. All TEM-24 positive strains belonged to the same clone.

Of all ESBL-producing strains, 57 (91.9 %) were susceptible to temocillin. All 63 ESBL positive strains (100%) were susceptible to cefepime and meropenem, with MICs < 1 µg/mL for most strains (90.5% for cefepime, 96.7% for meropenem).

Conclusions: ESBL-production was detected in 41.3% of E. aerogenes strains, 96.8%of these strains belonged to the same TEM-24 positive clone. All ESBL producing strains were susceptible to cefepime and meropenem, 91.9% was susceptible to temocillin.