Phenotypic detection of metallo-ß-lactamases in Pseudomonas aeruginosa and Acinetobacter baumannii isolated from hospitalized patients in São Luis, State of Maranhão, Brazil.

INTRODUCTION: Acquired metallo-ß-lactamases (MßL) are emerging determinants of resistance in Pseudomonas aeruginosa and Acinetobacter baumannii. The objectives of this study were to phenotypically detect MßL in imipenem-resistant P. aeruginosa and A. baumannii, to investigate the association between MßL-positive strains and hospitals, and to compare the resistance profiles of MßL-producing and non-MßL-producing strains. METHODS: The approximation disk and combined disk assay methods were used in this study. RESULTS: A total of 18 (38.3%) P. aeruginosa isolates and 1 (5.6%) A. baumannii isolate tested positive for the presence of MßL. CONCLUSIONS: These results demonstrate the need for strict surveillance and for the adoption of preventive measures to reduce the spread of infection and potential outbreaks of disease caused by MßL-producing microorganisms.

Nosocomial infection and characterization of extended-spectrum ß-lactamases-producing Enterobacteriaceae in Northeast Brazil.

INTRODUCTION: Extended spectrum ß-lactamases (ESBLs) are enzymes that degrade ß-lactam antibiotics and have been reported to be an important cause of nosocomial infection in worldwide. METHODS: During 2009, 659 enterobacteria strains were isolated from different clinical specimens and tested for ESBL production. The disk approximation test, combined disk method and addition of clavulanic acid were used for phenotypic detection of the ESBL-producing strains and PCR for detection of the bla(TEM) and bla(CTX-M) genes. RESULTS: Among the isolates, 125 were ESBL producers. The bla(CTX-M) and bla(TEM) genes were detected in 90.4% and 75% of the strains, respectively. Most strains were isolated from urine. Klebsiella pneumoniae was the most prevalent organism. Microorganisms presented high resistance to the antibiotics. CONCLUSIONS: These results support the need for extending ESBL detection methods to different pathogens of the Enterobacteriaceae family because these methods are only currently standardized by the CLSI for Escherichia coli, Klebsiella pneumoniae, Klebsiella oxytoca and Proteus mirabilis. Carbapenems were the antibiotic class of choice for the treatment of infections caused by ESBL-producing Enterobacteriaceae.

Nosocomial infection and characterization of extended-spectrum β-lactamases-producing Enterobacteriaceae in Northeast Brazil / Infecção hospitalar e caracterização de enterobactérias produtoras de β-lactamases de espectro ampliado no nordeste do Brasil

INTRODUCTION: Extended spectrum β-lactamases (ESBLs) are enzymes that degrade β-lactam antibiotics and have been reported to be an important cause of nosocomial infection in worldwide. METHODS: During 2009, 659 enterobacteria strains were isolated from different clinical specimens and tested for ESBL production. The disk approximation test, combined disk method and addition of clavulanic acid were used for phenotypic detection of the ESBL-producing strains and PCR for detection of the blaTEM and blaCTX-M genes. RESULTS: Among the isolates, 125 were ESBL producers. The blaCTX-M and blaTEM genes were detected in 90.4% and 75% of the strains, respectively. Most strains were isolated from urine. Klebsiella pneumoniae was the most prevalent organism. Microorganisms presented high resistance to the antibiotics. CONCLUSIONS: These results support the need for extending ESBL detection methods to different pathogens of the Enterobacteriaceae family because these methods are only currently standardized by the CLSI for Escherichia coli, Klebsiella pneumoniae, Klebsiella oxytoca and Proteus mirabilis. Carbapenems were the antibiotic class of choice for the treatment of infections caused by ESBL-producing Enterobacteriaceae.

INTRODUÇÃO: As β-lactamases de espectro ampliado (ESBLs) são enzimas que degradam os antibióticos β-lactâmicos e têm sido reportadas como uma importante causa de infecções hospitalares em todo o mundo. MÉTODOS: Em 2009, 659 enterobactérias foram isoladas de diferentes espécimes clínicos e testadas quanto à produção de ESBL. Os testes de aproximação do disco, disco combinado e adição do ácido clavulânico foram utilizados na detecção fenotípica das amostras produtoras de ESBL e PCR para a detecção dos genes blaTEM e blaCTX-M. RESULTADOS: Entre os isolados, 125 foram produtores de ESBL. Os genes blaCTX-M e blaTEM foram detectados em 90,4% e 75% das amostras, respectivamente. Com relação ao espécime clínico, a maioria das amostras foi isolada de urina. Klebsiella pneumoniae foi a espécie mais prevalente e o teste de susceptibilidade antimicrobiana mostrou uma elevada resistência dos microorganismos aos antibióticos testados. CONCLUSÕES: Estes resultados suportam a necessidade de se ampliar os métodos de detecção das ESBLs para os diferentes patógenos da família Enterobacteriaceae, uma vez que esses métodos estão padronizados pelo CLSI apenas para Escherichia coli, Klebsiella pneumoniae, Klebsiella oxytoca e Proteus mirabilis. Os carbapenens foram os antibióticos de escolha para o tratamento de infecções causadas por enterobactérias produtoras de ESBL.