Genomic epidemiology and genetic characteristics of clinical <i>Campylobacter</i> species cocirculating in West Bengal, India, 2019, using whole genome analysis

<i>Campylobacter</i> species are the most common pathogens responsible for foodborne gastroenteritis worldwide. India is a region with frequent diarrheal infections and a high level of <i>Campylobacter</i> infection incidence, but the detailed genomic information is limited. This study aimed to characterize 112 isolates of <i>Campylobacter</i> from diarrhea patients at two hospitals in Kolkata, West Bengal, by whole genome analysis. The <i>Campylobacter</i> isolates consisted of 90 <i>C</i>. <i>jejuni</i>, 20 <i>C</i>. <i>coli</i>, and 2 <i>C</i>. <i>lari</i> isolates. Multilocus sequence typing analysis revealed that the largest sequence type (ST) populations were ST-2131 in <i>C. jejuni</i> and ST-830 in <i>C. coli</i> and seven novel STs were found in <i>C. jejuni</i> and one in <i>C. coli</i>. Notably, ST-2131, which is rarely seen elsewhere, was positive for a sialylated LOS-related gene (<i>wlaN +neuA + cstIII</i>) associated with Guillain-Barré syndrome. Antibiotic resistance factors predicted from the genome sequence included <i>blaOXA</i> variants (58.9%), <i>tet(O)</i> (54.5%), <i>tet(W)</i> (0.9%), <i>ant(6)-Ia</i> (0.9%), mutation in GyrA (T86I, T86I+D90N, T86I+P104S, T86I+D90<i>N</i>+P104S) (79.5%), and mutation in 23S rRNA (A2075G) (12.5%). In addition to the high drug resistance of <i>Campylobacter</i> in Kolkata, <i>Campylobacter</i> pathogens were circulating that may be associated with Guillain-Barré syndrome. This study indicates the importance of genomic analysis in the surveillance of pathogens, which provides genomic information on genetic diversity, virulence mechanisms, and determinants of antimicrobial resistance.