Draft genome sequence based genomic characterization of Salmonella enterica subsp. enterica serovar Oslo isolated from clinical samples in South India and its comparison with global isolates.

Abstract

Non-typhoidal Salmonellae (NTS) are one of the significant food-borne pathogens with ≥2600 serovars and diverse range of hosts which significantly increases the chances of infections in humans. Salmonella enterica subsp. enterica serovar Oslo (S. Oslo) is a rare serovar, associated with foodborne illnesses. Here, we aim to report the draft whole genome sequences of S. Oslo ST2344 and ST1370 with reduced ciprofloxacin susceptibility, isolated from clinical samples. Thirty S. Oslo isolates were identified following the standard microbiological techniques. Twenty-six of the thirty (86.66%) S. Oslo isolates were pan-susceptible to the antimicrobials examined, except four isolates, which showed decreased ciprofloxacin susceptibility (MIC 0.12 - 0.50 µg/ml). PFGE analysis showed strains were heterogenous with two sequence types of ST1370 and ST2344 were observed in MLST. The average genome size of the four S. Oslo isolates ranged from 4,760,441 - 5,002,787 bp with average G+C content of 52 %. Different virulence genes encompassing Salmonella Pathogenicity Island (SPI) 1 to 5 linked to disease pathogenesis were found by genome analysis. The draft genome of S. Oslo clinical isolates gives an insight into the molecular characteristics of S. Oslo currently prevalent in India and the phylogenetic analysis sheds light on their evolutionary pattern.