Many virulence phenotypes of Salmonella enterica are encoded by genes located on pathogenicity islands. Based on genome analysis, it is predicted that Salmonella pathogenicity island (SPI)-8 is restricted to Salmonella serovars Typhi and Paratyphi A, and SPI-10 to Salmonella serovars Typhi, Paratyphi, Enteritidis, Dublin and Gallinarum. This study was conducted to investigate the distribution of SPI-8 and SPI-10 among Salmonella isolates from sprouts, fish, water and blood. A total of 110 Salmonella isolates and 6 Salmonella serovars from the Microbial Type Culture Collection, Chandigarh, India, were screened. All isolates belonging to Salmonella serovars Washington, Enteritidis and Paratyphi A had both SPI-8 and SPI-10. All Salmonella serovar Typhi isolates from water and blood had both SPI-8 and SPI-10, whereas isolates from fish contained only SPI-8. SPI-8 and SPI-10 were also detected in only 3 out of 42 isolates belonging to Salmonella serovar Typhimurium. Both SPI-8 and SPI-10 were absent in Salmonella serovars Worthington, Dublin, Paratyphi B and Paratyphi C. These results contradict the predictions from Salmonella genome sequences available in GenBank and indicate that SPI-8 and SPI-10 are widely distributed among Salmonella serovars and that virulence factors other than those on SPI-8 and SPI-10 may be responsible for host specificity. This is the first report on the distribution of SPIs in Salmonella isolates from India.
The availability and popularity of processed, ready-to-cook (RTC) poultry products are increasing in India. Though fresh poultry is known to be contaminated with Salmonella, the prevalence of this foodborne pathogen in RTC poultry products is not reported. Eighty-seven chilled and frozen RTC poultry samples of 4 different brands obtained from supermarkets and departmental stores in Mumbai were analyzed for the presence of Salmonella. The prevalence of Salmonella was higher (51%) in chilled RTC samples as compared to the frozen RTC samples (5%). The frozen RTC samples of one brand were free from Salmonella. S. Typhimurium (75.2%) was the most prevalent serovar, followed by S. Enteritidis (23%) and S. Weltevreden (1.7%). A high percentage (81.4%) of the isolates were found to be resistant to 5 or more antibiotics and class 1 integron, which has been shown to confer multi-drug resistance, was detected in 69.9% of the isolates. Multiple antibiotic resistance index of isolates was high (0.6) indicating the indiscriminate use of antibiotics during poultry farming. High genetic diversity was observed among the Salmonella serovars based on Pulsed Field Gel Electrophoresis profiles. Results showed the presence of multi-drug resistant Salmonella serovars in processed, chilled RTC poultry products marketed in Mumbai, India.
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