ESBL-producing Enterobecteriaceae and in vitro evaluation of tigecycline

Abstract number: 1734_50

Chinou E., Davlouros P., Georgouli M., Skoutelli E., Kamagiani A., Golemati P.

Objectives: This study was performed to investigate the prevalence of ESBL producers in Enterobecteriaceae isolated from oncology patients and to examine the in vitro activity of a new class of agents, tigecycline against these strains.

Materials and Methods: We studied 156 nonreplicate isolates of Enterobecteriaceae recovered over four months period (June to October 2006) from clinical specimens. Isolates were identified using Api 20E. ESBL production was screened for by MIC analysis (Microscan Gram negative) and confirmed by the double-disk synergy test. To examine the activity of tigecycline, we used the disk diffusion test on Mueller Hinton agar.

Results: A total of 102 E. coli, 38 K. pneumoniae, 10 K. oxytoca and 6 E. cloacae strains were detected among 156 Enterobecteriaceae isolates. 33.3% of clinical isolates were identified as ESBL producers (42 E. coli and 10 K. pneumoniae). The most efficient antibiotics for ESBLs were the carbapenems imipenem and meropenem (94.2% sensitive), amicacin (90.5%) and ciprofloxacin (62%). Tigecycline was active against all the tested strains of E. coli, K. oxytoca and E. cloacae. 5 strains of K. pneumoniae were resistant to tigecycline and sensitive only to carbapenems.

Conclusions: We detect an increase of ESBLs isolates. Their expression was usually associated with multidrug resistance. The invitro activity of tigecycline against Enterobecteriaceae and especially against ESBL producers was encouraging.