Molecular Epidemiology of Pasteurella multocida Circulating in India by Multilocus Sequence Typing.

Multilocus sequence typing (MLST), a sequence-based typing method for bacterial pathogens, is currently the best method for long-term epidemiological study and to understand the population structure of the bacteria. This investigation was carried out to study the diversity of Pasteurella multocida isolates circulating in India. Ten different sequence types (ST) identified in this study are ST 122 from cattle, goat, mithun and pig; ST 50 from pig; ST 9 from cattle and sheep; ST 229 from cattle and goat; ST 71 and ST 277 from cattle; and ST 129, ST 280, ST 281 and ST 282 from avian species. Of these, ST 277, ST 280, ST 281 and ST 282 were identified for the first time. The analysis of results provides novel epidemiological information on the circulation of multiple STs across India. The majority of STs or their variants identified in this study have already been reported from different parts of the globe. This suggests that probably transboundary spread of strains across countries and continents has occurred across evolutionary time and is still happening. The isolation of ST 122 from small ruminants and pigs suggests that these species may be included in the preventive vaccination policy for effective control of haemorrhagic septicaemia in India.