Prevalence and Characterization of Plasmid-Mediated Quinolone Resistance Genes in Extended-Spectrum β-Lactamase–Producing Enterobacteriaceae Isolates in Mexico

Abstract

The objectives of this study were to investigate the prevalence of plasmid-mediated quinolone resistance genes in a collection of 226 extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae isolates and characterize the qnr-positive isolates. The rate of qnr-positive isolates was 21.6% (49/226), 49.5% for aac(6')-Ib-cr (112/226), and 1.7% for qepA1 (4/226). Those isolates carried qnr genes corresponding to types qnrB (71.4%), qnrS1 (24.4%), and qnrA1 (18.3%). The distribution among bacterial species was as follows: 55.8% (19/34) to Enterobacter cloacae, 50% (28/56) to Klebsiella pneumoniae, and 1.4% (2/136) to Escherichia coli. The characterization of qnr-positive isolates indicated the ESBL SHV-types as the most prevalent (81.6%), including the ESBLs SHV-12, SHV-5, and SHV-2a, followed by CTX-M-15 (44.9%) and TLA-1 (8.1%). In addition, for qnr-positive isolates, the prevalence of aac(6')-Ib-cr was 55.1%, but qepA was not identified. Alterations at codons Ser-83 and Asp-87 in GyrA and at codons Ser-80 in ParC were observed in 69% and 80% of the qnr-positive isolates, respectively. The analysis of the transconjugants revealed a cotransmission of bla(CTX-M-15) with qepA1 or aac(6')-Ib-cr and/or qnrA1 and bla(SHV-type) with qnrB5 and qnrB6 genes. To conclude, these findings indicate a high prevalence of qnr and aac(6')-Ib-cr among ESBL-producing isolates from Mexican hospitals and point to the wide spread of qnr-like determinants associated to ESBLs SHV- and CTX-M-type in Mexican clinical isolates.

Prevalence of plasmid-mediated quinolone resistance determinants among oxyiminocephalosporin-resistant Enterobacteriaceae in Argentina

“…Nevertheless, comparisons between these studies should be performed carefully due to the different bacterial selection criteria used. In concordance with a multicentre study performed in Mexico (Silva-Sanchez et al 2011), we observed a high frequency of qnrB and aac(6')-Ib-cr genes amongst ESBL-producing isolates. However, a very low proportion of these markers were detected in Enterobacteriaceae isolated in a paediatric hospital in Uruguay (Garcia-Fulgueiras et al 2011).…”

Contribution of IncFII and Broad-Host IncA/C and IncN Plasmids to the Local Expansion and Diversification of Phylogroup B2 Escherichia coli ST131 Clones Carrying bla CTX-M-15 and qnrS1 Genes

“…The qnrS1 gene was detected among 48.5% of CTX-M-15 E. coli producers, a rate similar to that obtained in another survey from Mexico (44.9%) (20) and higher than that observed in other studies from areas as distant as Europe or North Africa (2 to 16%) (2,7,8). This gene was frequent among B2 ST131 isolates (13/21; 62%) but also present among E. coli clones, such as A-ST410 (22), located on the IncFII (n ϭ 5), IncN (40 to 55 kb, n ϭ 3), or IncA/C (150 kb, n ϭ 1) plasmid and occasionally carrying bla CTX-M- 15 , that are predominant in Spain and other countries.…”

High Diversity of CTX-M Extended-Spectrum β-Lactamases in Municipal Wastewater and Urban Wetlands

“…While no studies of CTX-M diversity in the cities of San Diego, California, and Tijuana, Mexico, are available for comparison, CTX-M-15 appears to be the predominant CTX-M variant in the state of California 2,40 and across Mexico. 18,35,36,49,50 The low representation of the globally predominant variant of CTX-M in the WWTPs and wetlands may reflect regional variation in its distribution or it may be due to a unique genetic context that impeded detection by our primers. Recall that the PCR primers used in this study anneal to sequences within the ISEcp1 element, thus only allowing for the amplification of those bla CTX-M genes located within this genetic context.…”