RESUMEN
Background & objectives: Bacillary dysentery caused by Shigella spp. remains an important cause of the crisis in low-income countries. It has been observed that Shigella species have become increasingly resistant to most widely used antimicrobials. In this study, the antimicrobial resistance, virulence and plasmid profile of clinical isolates of Shigella species were determined. Methods: Sixty clinical Shigella isolates were subjected to whole-genome sequencing using Ion Torrent platform and the genome sequences were analyzed for the presence of acquired resistance genes, virulence genes and plasmids using web-based software tools. Results: Genome analysis revealed more resistance genes in Shigella flexneri than in other serogroups. Among ß-lactamases, blaOXA-1was predominantly seen followed by the blaTEM-1B and blaEC genes. For quinolone resistance, the qnr S gene was widely seen. Novel mutations in gyr B, par C and par E genes were observed. Cephalosporins resistance gene, blaCTX-M-15 was identified and plasmid-mediated AmpC ß-lactamases genes were found among the isolates. Further, a co-trimoxazole resistance gene was identified in most of the isolates studied. Virulence genes such as ipaD, ipaH, virF, senB, iha, capU, lpfA, sigA, pic, sepA, celb and gad were identified. Plasmid analysis revealed that the IncFII was the most commonly seen plasmid type in the isolates. Interpretation & conclusions: The presence of quinolone and cephalosporin resistance genes in Shigella serogroups has serious implications for the further spread of this resistance to other enteric pathogens or commensal organisms. This suggests the need for continuous surveillance to understand the epidemiology of the resistance.
Asunto(s)
Proteínas Bacterianas/genética , Farmacorresistencia Bacteriana/genética , Disentería Bacilar/genética , Shigella/genética , beta-Lactamasas/genética , Antibacterianos/efectos adversos , Antibacterianos/uso terapéutico , Cefalosporinas/efectos adversos , Cefalosporinas/uso terapéutico , Disentería Bacilar/tratamiento farmacológico , Disentería Bacilar/epidemiología , Disentería Bacilar/microbiología , Heces/microbiología , Humanos , Pruebas de Sensibilidad Microbiana , Plásmidos/efectos de los fármacos , Plásmidos/genética , Serogrupo , Shigella/patogenicidad , Secuenciación Completa del GenomaRESUMEN
Multi-drug resistance and transfer of mobile genetic elements among enteric pathogens is being reported to have increased rapidly. Commensal Escherichia coli was previously known to acquire mobile genetic elements from other genus/species. E. coli is also capable of disseminating these elements containing antimicrobial resistance determinants through horizontal transfer. Similarly, for Shigellae the antimicrobial resistance are on rise for fluoroquinolones and cephalosporins due to accumulation of mobile elements. Thus the study was hypothesized to investigate the role of transferable plasmids in commensal MDR E. coli vs Salmonella spp, and MDR Shigella flexneri vs Salmonella spp. pKP3-A plasmid containing qnrS1 was successfully transferred from E. coli to Salmonella spp. Similarly, a plasmid containing qnrS1 and blaCTX-M-15 was transferred from Shigella to Salmonella spp. However, blaCTX-M-15 was not transferred from E. coli as it was integrated into chromosome that was revealed by next-generation sequencing. This might be a reason that fluoroquinolone-resistant determinants are more frequently transferred than the cephalosporin resistant determinants. Findings from the study emphasize that mobile elements with AMR determinants are significant public health concern that has potential to rapidly disseminate.