β-lactamase-producing Gram-negative bacteria in an intensive care unit in southern Brazil

Abstract

ABSTRACT The present study evaluated the antimicrobial susceptibility profile, β-lactamase production, and genetic diversity of Enterobacteriaceae, Pseudomonas aeruginosa, and Acinetobacter spp. using phenotypic identification, antimicrobial susceptibility testing, and β-lactamase phenotypic detection. Isolates were obtained from patients in an intensive care unit in a hospital in southern Brazil. Bacterial genomic DNA was extracted, followed by the genotypic detection of carbapenemases and enterobacterial repetitive intergenic consensus-polymerase chain reaction (ERIC-PCR). Fifty-six isolates (26 Klebsiella pneumoniae, five Escherichia coli, three Enterobacter aerogenes, nine P. aeruginosa, and 13 Acinetobacter spp.) were evaluated. The phenotypic extended spectrum β-lactamase (ESBL) test was positive in 53.8% of the K. pneumoniae isolates, 100.0% of the E. coli isolates, and 100.0% of the E. aerogenes isolates. Phenotypic and genotypic testing of K. pneumoniae carbapenemase (KPC) was positive in 50.0% of the K. pneumoniae isolates. Phenotypic and genotypic testing showed that none of the P. aeruginosa or Acinetobacter spp. isolates were positive for metallo- β-lactamase (MBL). The bla OXA gene was detected only in Acinetobacter spp. The lowest genetic diversity, determined by ERIC-PCR, was observed among the KPC-producing K. pneumoniae isolates and OXA-producing Acinetobacter spp. isolates, indicating the inadequate dissemination control of multidrug-resistant bacteria in this hospital environment.

Keywords

• Enterobacteriaceae
• Pseudomonas aeruginosa
• Acinetobacter spp
• Antimicrobial resistance
• Beta-lactamases
• Bacterial typing
• Intensive Care Unit/study/Brazil
• Drug-resistant bacteria.