Molecular biology of beta-lactamases and other resistance genes. Plasmids, integrons etcTuesday, April 22, 2008, 12:30 - 13:30Recent dissemination of blaTEM-52-producing Enterobacteriaceae in Portugal is caused by spread of IncI plasmids among Escherichia coli and Klebsiella clonesA. Tedim Pedrosa, A. Novais, E. Machado, R. Cantón, L. Peixe, T. M. Coque (Porto, PT; Madrid, ES)
Objectives: Since its first description in 1996, TEM-52 has been sporadically identified in Europe, Korea and Canada among Enterobacteriaceae from both human and animals. An epidemic IncI1 plasmid containing blaTEM-52 has been recently identified among Salmonella enterica in France. We analyzed the diversity of TEM-52 producing isolates from Portugal in order to understand the reasons for recent spread in our country.
Methods: Twenty one TEM-52-producing isolates recovered from Portugal (n=19 Escherichia coli; n=2 Klebsiella pneumoniae) between 2002 and 2005 were studied. The isolates were obtained from hospitals (n=7), poultry (n=12) and sewage (n=2). Only one isolate/phenotype was included. Clonality was established by PFGE and E. coli phylogenetic groups by PCR as reported. ESBL identification was achieved by IEF, PCR and sequencing. Standard methods were used for conjugation assays as well as antibiotic susceptibility testing. bla location was accessed by hybridization of I-CeuI-digested DNA with an intragenic blaTEM-52 probe. Plasmid characterisation was accomplished by the Barton’s method, identification of plasmid incompatibility groups by PCR, hybridization and sequencing, and analysis of RFLP patterns. Presence of sul genes and class 1 and 2 integrons was searched in wild-type strains by PCR.
Results: High clonal diversity was found among studied isolates (n=21 PFGE-types). Most E. coli clinical isolates were assigned to phylogenetic group B1. E. coli recovered from poultry and sewage were identified as phylogroups A (4 A0 and 3 A1), B1 (n=2) and D (3 D1 and 1 D2). Conjugation was achieved in 71% of the isolates. blaTEM-52 gene was carried by two different plasmids of approximately 90kb and 30kb. They contain sequences characteristic of incompatibility groups IncI1 (90kb) and IncK (30kb), both belonging to the IncI plasmid group. All isolates harboured one or more sul genes: sul1 (47%) mainly associated with class 1 integrons, sul2 (65%) and sul3 (35%) which was mainly present in poultry isolates.
Conclusions: Wide and recent dissemination of blaTEM-52 among E. coli and K. pneumoniae strains from Portugal seems to be associated with IncI plasmids rather than clonal expansion.
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