Antimicrobial resistance, plasmid, virulence, multilocus sequence typing and pulsed-field gel electrophoresis profiles of Salmonella enterica serovar Typhimurium clinical and environmental isolates from India

Abstract

Salmonella enterica serovar Typhimurium (S. Typhimurium) is a common serovar associated with non-typhoidal salmonellosis globally. However, there is insufficient data on molecular characterization of S. Typhimurium isolates from India. This study was undertaken to determine the antimicrobial resistance (AMR), plasmid, virulence profiles and molecular subtypes of S. Typhimurium Indian isolates (n = 70) of clinical and environmental origin isolated during 2010–2017. Antimicrobial susceptibility and minimum inhibitory concentrations were determined by disc diffusion and E-test methods respectively. Plasmid extraction was done following standard protocol. AMR genes, virulence genes and plasmid incompatibility types were detected by PCR; Pulsed-field gel electrophoresis (PFGE) and multi-locus sequence typing (MLST) were used for molecular subtyping. Majority (57%) of the study isolates was pan susceptible; five AMR profiles were observed among the resistant (43%) isolates. AMR was significantly (p = 0.004) associated with extra-intestinal isolates than intestinal isolates.The class 1 integron and plasmid-mediated quinolone resistance genes (qnrB1, qnrS1) in the resistant isolates were transferable by conjugation. Plasmids (≥1) ranging from 1.9 to 254kb size and of IncFIIS and/or FIB type were found in most isolates. A total of 39 pulsotypes by PFGE and four sequence types by MLST like ST36 (55.7%), ST19 (32.9%), ST313 (10%) and ST213 (1.4%) were observed. ST36 and ST19 were found circulating in both clinical and environmental host, while ST313 isolates had an exclusive clinical origin. All ST19 isolates (100%) were drug-resistant, while isolates belonging to ST313 (100%), ST213 (100%) and ST36 (82%) were pan susceptible. The virulence plasmid (VP) genes (spvB- spvC) were present in all genotypes except ST36. The VP was significantly (p<0.001) associated with extra-intestinal than intestinal isolates. Some environmental and clinical isolates were clonal indicating their zoonotic transmission. Knowledge on the molecular subtypes and AMR profiles of locally prevalent Salmonella serotypes is important for effective control of spread of resistant organisms. The MLST of S. Typhimurium isolates and its association with AMR, virulence profiles was not reported earlier from India.

Characterization of non-typhoidal Salmonella isolates from children with acute gastroenteritis, Kolkata, India, during 2000–2016

“…Conjugation experiment was attempted by broth mating procedure in Tryptic soy broth (Difco), using sodium azideresistant E. coli J53 as the recipient strain and resistant Salmonella strains as donors [42]. Transconjugants were selected as lactose-fermenting colonies of E. coli on MacConkey agar supplemented with sodium azide (100 μg/ml) and one of the following antibiotics: chloramphenicol (16 μg/ml) or cefotaxime (4 μg/ml).…”

“…The designation of the clusters (A-H) representing serovars Enteritidis, Weltevreden, Typhimurium, Bareilly, Kentucky, Worthington, Virchow, and Infantis respectively has been retained as in Fig. 4 The characteristics of S. Typhimurium fecal isolates described in this study were partially published in our earlier study [42].…”

Emergence of NDM-5-Producing Escherichia coli in a Teaching Hospital in Chongqing, China: IncF-Type Plasmids May Contribute to the Prevalence of blaNDM–5

“…Briefly, genomic DNA of the bla NDM−5 -positive E. coli isolates was prepared in agarose blocks and digested with restriction enzyme XbaI. DNA fragments were separated using a CHEF II D-Mapper XA PFGE system (Bio-Rad, Hercules, California, CA, United States) with running conditions as described previously (Jain et al, 2018).…”

High Prevalence of Metal Resistant Genes in <em>Salmonella enterica</em> MDR Plasmids Correlates Severe Toxicities of Water with higher Typhoid AMR

“…Surprisingly, ampC beta-lactamse producing plasmids were not detected in the database but many papers had detected such gene in Salmonella sp (Roschanski et al 2014). The genetic exchange and acquisition of mdr genes were happed in the gut and thus gut microbiome plaed a central role in shaping both mdr and metal resistant genes (Jain et al 2018). WGS of Salmonella has showed the existence of MDR-islands in Salmonella genome and thus virulence and multi-resistance will be more prominence in Salmonella infections (Saroj et al 2008;Liu et al 2009;Sudhanthirakodi et al 2016;Parkhill et al 2018;Luo et al 2020)…”