Horizontol dissemination of TEM- and SHV-typr beta-lactamase genes-carrying resistance plasmids amongst clonical isolates of Enterobacteriaceae / Disseminação horizontal de plasmídios de resistência contendo genes de beta-lactamase dos tipos TEM e SHV entre isolados clínicos de Enterobacteriaceae

The extended-spectrum â-lactamase (ESBL)-producing bacteria have been isolated at increasing frequency worldwide. Expression of ESBL is often associated with multidrug resistance and dissemination by resistance plasmids. During a two-month period in 2000, 133 clinical isolates of enterobacterial strains were randomly collected from outpatients and inpatients at a university hospital in Turkey. The ESBL producing strains were determined by double-disk synergy (DDS) testing. Twenty ESBL producing strains (15 percent) including Escherichia coli (n = 9), Klebsiella pneumoniae (n = 7), Klebsiella oxytoca (n = 2) and Enterobacter aerogenes (n = 2) were detected and further analyzed for their resistance transfer features, plasmid profile and nature of the resistance genes. Plasmid transfer assays were performed using broth mating techniques. TEM- and SHV- genes were analyzed by polymerase chain reaction (PCR) and hybridization using specific probes. EcoRI restriction enzyme analyses of R plasmids were used in the detection of epidemic plasmids. Fourteen plasmid profiles (A, B1, B2, C1, and C2 to L) were obtained with EcoRI restriction enzyme analysis. Most of these plasmids were detected to carry both TEM- and SHV-derived genes by PCR, and confirmed by localizing each gene by hybridization assay. Epidemiological evidence indicated that there was an apparent horizontal dissemination of conjugative R plasmids among multidrug-resistant enterobacterial genera and species in this hospital

O isolamento de bactérias produtoras de beta-lactamases de espectro expandido (ESBL) está aumentando no mundo todo. Freqüentemente, a expressão de ESBL está associada com resistência a múltiplas drogas e disseminação por plasmídios de resistência. Durante um período de dois meses em 2000, 133 isolados clínicos de cepas de enterobactérias foram obtidos aleatoriamente de pacientes internos e externos de um hospital universitário na Turquia. As cepas produtoras de ESBL foram identificadas pelo teste de sinergia em disco-duplo (DDS). Foram detectadas vinte cepas produtoras de ESBL, entre as quais Escherichia coli (n=9), Klebsiella pneumoniae (n=7), Klebsiella oxytoca (n=2) e Enterobacter aerogenes (n=2), que foram posteriormente analisadas quanto a suas características de transferência de resistência, perfil plasmidial e natureza dos genes de resistência. Os testes de transferência de plasmídios foram realizados empregando técnicas de conjugação em caldo. Os genes TEM e SHV foram analisados pela reação da polimerase em cadeia (PCR) e hibridização com sondas especificas. A detecção de plasmídios epidêmicos foi feita por análise dos plasmídios R com a enzima de restrição EcoRI. Através desta análise, foram obtidos catorze perfis plasmidiais (A, B1, B2, C1 e C2 até L).Observou-se pela PCR que a maioria dos plasmidios carregavam genes derivados de TEM e SHV, confirmados através da detecção dos genes pelos testes de hibridização. As evidencias epidemiológicas indicaram que havia uma aparente transferência horizontal dos plasmídios R conjugativos entre as enterobactérias multiresistentes neste hospital.

Horizontol dissemination of TEM- and SHV-typr beta-lactamase genes-carrying resistance plasmids amongst clonical isolates of Enterobacteriaceae.

The extended-spectrum ß-lactamase (ESBL)-producing bacteria have been isolated at increasing frequency worldwide. Expression of ESBL is often associated with multidrug resistance and dissemination by resistance plasmids. During a two-month period in 2000, 133 clinical isolates of enterobacterial strains were randomly collected from outpatients and inpatients at a university hospital in Turkey. The ESBL producing strains were determined by double-disk synergy (DDS) testing. Twenty ESBL producing strains (15%) including Escherichia coli (n = 9), Klebsiella pneumoniae (n = 7), Klebsiella oxytoca (n = 2) and Enterobacter aerogenes (n = 2) were detected and further analyzed for their resistance transfer features, plasmid profile and nature of the resistance genes. Plasmid transfer assays were performed using broth mating techniques. TEM- and SHV- genes were analyzed by polymerase chain reaction (PCR) and hybridization using specific probes. EcoRI restriction enzyme analyses of R plasmids were used in the detection of epidemic plasmids. Fourteen plasmid profiles (A, B1, B2, C1, and C2 to L) were obtained with EcoRI restriction enzyme analysis. Most of these plasmids were detected to carry both TEM- and SHV-derived genes by PCR, and confirmed by localizing each gene by hybridization assay. Epidemiological evidence indicated that there was an apparent horizontal dissemination of conjugative R plasmids among multidrug-resistant enterobacterial genera and species in this hospital.