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

Author(s)

Dropa, Milena ; Balsalobre, Livia C. ; Lincopan, Nilton ^[1] ; Matte, Glavur R. ; Matte, Maria H.

Affiliation

^[1] Univ Sao Paulo, Inst Biomed Sci, Dept Microbiol, Butanta - Brazil

• Document type: Journal article
• Source: JOURNAL OF INFECTION IN DEVELOPING COUNTRIES; v. 9, n. 8, p. 890-897, AUG 2015.
• Web of Science Citations: 15

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 bla(CTX-M) genes from clinical Enterobacteriaceae strains. Methodology: Twenty-eight clinical non-clonal Enterobacteriaceae were screened by PCR for the presence of bla(CTX-M) genes and class 1 integrase (int1), and for the association of bla(CTX-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 bla(CTX-M-2) (n = 25) and bla(CTX-M-59) (n = 3) genes inserted into the 3'-end of complex class 1 integrons. Thirteen strains also carried bla(TEM) and bla(SHV) 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 bla(CTX-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 bla(CTX-M-2) accounts for their maintenance and spread among Gram-negative bacteria. (AU)

• FAPESP's process: 10/12841-1 - Identification and localization of ²-lactam and tetracycline resistance genes, in clinical and environmental Enterobacteriaceae and Aeromonas hydrophila strains
• Grantee: Maria Helena Matte
• Support Opportunities: Regular Research Grants
• FAPESP's process: 08/08312-3 - Molecular identification of ESBL-encoding resistance genes, detected in Enterobacteriaceae clinical strains related to hospital infections
• Grantee: Maria Helena Matte
• Support Opportunities: Regular Research Grants