Complex class 1 integrons harboring CTX-M-2-encoding genes in clinical Enterobacteriaceae from a hospital in Brazil

  • Milena Dropa School of Public Health, University of São Paulo, São Paulo, Brazil
  • Livia Carminato Balsalobre School of Public Health, University of São Paulo, São Paulo, Brazil
  • Nilton Lincopan Institute of Biomedical Sciences, University of São Paulo, Butantã, Brazil
  • Glavur Rogério Matté School of Public Health, University of São Paulo, São Paulo, Brazil
  • Maria Helena Matté School of Public Health, University of São Paulo, São Paulo, Brazil

Abstract

Introduction: CTX-M enzymes are the most prevalent extended-spectrum beta-lactamases (ESBLs) in Brazil and around the world. The spread of CTX-M lies in their ability to be mobilized by insertion sequences and integrons. This study aimed to identify the mobile genetic structures associated with blaCTX-M genes from clinical Enterobacteriaceae strains.

Methodology: Twenty-eight clinical non-clonal Enterobacteriaceae were screened by PCR for the presence of blaCTX-M genes and class 1 integrase (int1), and for the association of blaCTX-M with class 1 integrons. Plasmid incompatibility groups were assessed by PBRT. Wild-type plasmids were transformed into electrocompetent E. coli, and the S1-PFGE technique was used to verify the presence of high-molecular-weight plasmids in both wild-type strains and E. coli transformants.

Results: Sequencing showed that strains carried blaCTX-M-2 (n = 25) and blaCTX-M-59 (n = 3) genes inserted into the 3’-end of complex class 1 integrons. Thirteen strains also carried blaTEM and blaSHV genes. CTX-M-2/59-containing complex class 1 integrons were also present in E. coli transformants. The most frequent Inc groups were IncA/C (n = 10) and IncF (n = 8). Heavy plasmids were observed in both wild-type strains and E. coli transformants.

Conclusions: The presence of the same blaCTX-M-2-group-containing genetic structure in seven Enterobacteriaceae species isolated at seven hospital wards shows the great mobility potential of complex class 1 integrons. Also, this is the first report of TEM-15, SHV-45, and SHV-55 in Latin America. The genetic environment of blaCTX-M-2 accounts for their maintenance and spread among Gram-negative bacteria.

Author Biographies

Milena Dropa, School of Public Health, University of São Paulo, São Paulo, Brazil
PhD Research Assistant at Public Health Laboratory
Livia Carminato Balsalobre, School of Public Health, University of São Paulo, São Paulo, Brazil
PhD Student
Nilton Lincopan, Institute of Biomedical Sciences, University of São Paulo, Butantã, Brazil
PhD Professor at the University of São Paulo
Glavur Rogério Matté, School of Public Health, University of São Paulo, São Paulo, Brazil
Associate Professor at the University of São Paulo
Maria Helena Matté, School of Public Health, University of São Paulo, São Paulo, Brazil
Associate Professor at the University of São Paulo
Published
2015-08-29
How to Cite
Dropa M, Balsalobre L, Lincopan N, Matté G, Matté M (2015) Complex class 1 integrons harboring CTX-M-2-encoding genes in clinical Enterobacteriaceae from a hospital in Brazil. The Journal Of Infection In Developing Countries 9 (08): 890-897. https://doi.org/10.3855/jidc.6241
Section
Brief Original Articles

Keywords

complex class 1 integron; CTX-M-2; CTX-M-59; Enterobacteriaceae; Brazil