C2-3884. Prevalence and Molecular Relatedness of Extended-Spectrum Beta-Lactamases (ESBL) Produced by Escherichia coli Isolated from Hospitalized Patients in Germany
Session: Poster Session: E. coli and Klebsiella: Resistance Trends and Their Clinical Significance
Tuesday, October 28, 2008: 12:00 AM
Room: Hall C
Background: The rate of ESBL producing strains among Escherichia coli isolates (ECO) has been reported to increase in many countries. The objectives of this study were to evaluate the occurrence of ESBL-producing isolates among ECO collected during the German T.E.S.T. (G.-T.E.S.T.) Surveillance Program and to characterize the type of ESBLs. Methods: A total of 300 ECO recovered from 15 laboratories during 2005 was studied. ESBL-producing organisms were detected and confirmed according to the broth dilution procedure described by the CLSI. Antibacterial agents tested were cefotaxime, ceftazidime, alone and in combination with clavulanic acid, piperacillin-tazobactam (P/T), ciprofloxacin (CIP), gentamicin (GEN), imipenem (IMP) and tigecycline (TGC). Isolates expressing an ESBL phenotype were further characterized by isoelectric focusing (IEF), amplification of bla genes using specific primers for TEM, SHV or CTX-M ESBL type, and sequencing. Molecular relatedness was determined by pulsed-field gel electrophoresis (PFGE). Results: Among the 300 ECO, 16 (5.3%) were ESBL producers. According to IEF and PCR results, 14/16 isolates harboured a CTX-M variant, while 2 harboured a TEM derivative. Sequence analysis of blaCTX-M revealed that 8 and 5 isolates produced CTX-M-1 and CTX-M-15, respectively (one with unclear results). Three isolates producing CTX-M-1 were also positive for blaTEM-1. The 2 isolates expressing a TEM ESBL carried TEM-26 and were clonally related. In contrast, CTX-M producing strains were unrelated. Resistance to P/T, CIP and GEN was detected in 3, 11, 6 isolates, respectively, while all isolates were susceptible to IMP and TGC. Conclusions: CTX-M-1 was predominant among German ESBL-producing isolates of ECO, followed by CTX-M-15. TEM-26 was detected for the first time in Germany.
Adolf Bauernfeind1, Barbara Körber-Irrgang, PhD2, Ines Schneider1, Lilyana Georgieva3, Michael Kresken, PhD4, Volker Dahmen4 and  V. Dahmen, None., (1)Micoer, (2)Antiinfectives Intelligence GmbH, (3)University of Applied Sciences, (4)Antiinfectives Intelligence GmbH, Rheinbach, Germany