Plasmid Carrying bla(CTX-M-15), bla(PER-1), and bla(TEM-1) Genes in Citrobacter spp. From Regional Hospital in Mexico

INTRODUCTION: Citrobacter spp. is an opportunistic bacteria that have been recognized as significant pathogens in patients with underlying diseases or immunocompromised status. The aim of this study was to identify extended-spectrum β-lactamases in clinical isolates of Citrobacter spp. METHODS: This cross-sectional study was conducted at Hospital Central “Dr. Ignacio Morones Prieto” in San Luis Potosi, Mexico. Nineteen isolates of Citrobacter spp. were obtained from clinical specimens between April to December 2015. Four isolates were resistant to third-generation cephalosporins. The presence of genes encoding ESBL (bla(CTX-M-15), bla(TEM-1), bla(VEB-1), bla(SHV), and bla(PER-1)) was analyzed by PCR. For this purpose, plasmid DNA was extracted and horizontally transferred to recipient E. coli Top 10. RESULTS: bla(CTX-M-15) and bla(VEB-1) genes were detected in Citrobacter freundii and Citrobacter sedlakii, whereas bla(PER-1) gene was identified in 1 isolate of Citrobacter freundii. In contrast, bla(SHV) gene was not detected in any isolate. One strain carried bla(CTX-M-15), bla(TEM-1), bla(VEB-1), and bla(PER-1) genes, most in a 275-kb plasmid. CONCLUSION: This study shows the presence of different types of ESBL in clinical isolates of Citrobacter freundii and Citrobacter sedlakii, which confer resistance to broad-spectrum β-lactams. The plasmid identified in this study harboring ESBL genes could play an important role in the dissemination of antibiotic resistance.