Prevalence of community-occurring extended spectrum beta-lactamase-producing Enterobacteriaceae in Brazil

The occurrence of extended-spectrum-beta-lactamase (ESBL)-producing strains in the community was investigated in a private laboratory located in Juiz de Fora, Brazil. All enterobacterial isolates analysed were collected from urine of human patients between the years 2000 and 2002. ESBL production was confirmed by double disk screening, combination disk method, and Etest ESBL strip. The isoelectric point of each beta-lactamase was determined in the crude extracts from each isolate. Detection of ESBL genes was performed by polymerase chain reaction and the genetic relatedness of the isolates determined by pulsed-field gel electrophoresis (PFGE). Of the 1,481 isolates, 22 (12 Klebsiella pneumoniae, 7 Escherichia coli, 1 Providencia stuartii, 1 Citrobacter freundii, and 1 Serratia marcescens) were identified as ESBL producers. The frequency of ESBL producers in the community was 1.48%. TEM-type enzymes were identified in 95.4% of the isolates, followed by the SHV type. Seven strains produced CTX-M-type enzymes. This study showed that strains producing multiple beta-lactamases are also present in community-acquired bacterial isolates. Multiple strains exhibiting identical PFGE genotypes were found in individual patients indicating a common source of acquisition.