Commensal and virulent Escherichia coli strains of vaginal origin are reservoirs of resistance cassettes in class 1 integrons

Abstract

Introduction: Antimicrobial resistance in Escherichia coli, one of the causal agents of aerobic vaginitis, leads to the persistence of the infection. The investigation of integrons acquires relevance, since they are elements that are responsible for the acquisition of resistance to antibiotics. The aim of this work was to describe the structural diversity of class 1 integrons in virulent and commensal strains of E. coli isolated from patients with vaginal infection.
 Methodology: Ninety-two strains of E. coli were isolated from patients with aerobic vaginitis. Resistance profile against 19 antibiotics and class 1 integrons were detected by PCR. The identity and arrangement of cassettes was determined by sequencing. ERIC-PCR assays were carried out in strains with identical arrays. Finally, genotyping by Clermont algorithm and serotyping were performed. Seventeen strains showed integrons located in plasmids.
 Results: Ten different gene cassette arrays were identified in 30 strains of E. coli. Cassettes corresponding to genes coding for adenylyltransferases (aadA), dihydrofolate reductases (dfrA), and oxacillinases (blaOXA) were detected. Array dfrA17-aadA5 was predominantly prevalent over the other arrays identified. Phylogenetic group A was the most predominant, followed by group B2 and D.
 Conclusions: This study demonstrates the presence of E. coli of vaginal origin carrying class 1 integrons, which are main genetic elements of capture of resistance genes, with the possibility of capturing new resistance cassettes. These evidences should serve for the modification of protocols in the diagnosis and treatment of aerobic vaginitis, and the development of policies for the rational use of antimicrobials.

Genotyping of Escherichia coli Causing Vaginal Infection in Dysplastic Patients with Similar Genetic Backgrounds Between Commensal and Virulent Strains

“…In this study, the E. coli strains showed resistance mainly to β-lactams and sulfonamides; similar results were observed in a previous study (7). Seventy-three percent of the strains were resistant to three or more antibiotics, agreeing with other reports (13,14).…”

“…The Wizard ® Genomic DNA Purification Kit (Promega Corporation, Madison, USA) was used for total DNA extraction. Prior to phylogenetic assignment, the 16S rRNA gene was amplified to verify the quality and amplifiability of the DNA samples (7). Clermont et al (10) proposed a dichotomous analysis based on the chuA, yjaA, and arpA genes and the anonymous fragment designated as TspE4.C2 proposing six main phylogenetic groups in E. coli strains of different origins.…”

“…Class 1 genes are the most studied since they are found in Gram-negative strains of clinical origin, playing an essential role in bacterial resistance and in generating and expressing antibiotic resistance cassettes (6). A previous study of our group demonstraTed that the Class 1 integrons of E. coli of vaginal origin were reservoirs of an-timicrobial resistance genes (7). However, there is still controversy about the role of this bacterium as a causal agent of this type of pathology since the presence of the main virulence genes associated with cytotoxicity and adhesion is not considered.…”

Virulence gene transcription, phylogroups, and antibiotic resistance of cervico-vaginal pathogenic E. coli in Mexico

“…The frequency of aerobic cervicovaginal infections (CVI) in women of reproductive age caused by cervico-vaginal E. coli (CVEC) is 11% [3]. Transmission of E. coli in CVI has been shown to be due to the anatomical proximity of the "anorectal/vagina" region [4]. The pathogenicity of E. coli is due to several virulence factors including adhesins, iron acquisition systems, toxins, and protectins [5].…”

Genetic and phenotypic determinants of resistance to antibiotics in Aeromonas spp., strains isolated from pediatric patients

“…For screening of class 1 integron elements, all strains were screened as follows: [integrase 5´(Int1I)variable region-(qacEΔ1-sulI)3´] by using the primers described in Table 1, and PCR conditions were performed according to Blancarte-Lagunas et al, 2020 [32]. The identity of resistance cassettes was also determined by sequencing the PCR amplicons.…”