Incidence and virulence properties of E coli isolated from fresh fish and ready-to-eat fish products

Abstract

Aim: To investigate the incidence and virulence properties of E. coli in fresh fish and ready-to-eat fish products from retail markets of the Ludhiana the present study was conducted. Materials and Methods:Total of 184 samples comprising 96 raw fish and 88 ready-to-eat (RTE) fish products were collected from Ludhiana and other parts of Punjab and were subjected to suitable microbiological methods for E. coli isolation. E. coli isolates were subjected for haemolytic activity and indicators of plausible cytotoxicity (lecithinase, protease and gelatinase production), congo red dye biding assay. To assess virulence potential isolates were molecularly screened for stx 1 and 2 genes.Results: From raw fish samples 47(48.95%), E. coli, were isolated. From RTE fish products 7(12.96%), E. coli were isolated. Overall incidence for E. coli was 54 (29.34%). In vitro virulence characterization of isolates exhibited that all E. coli isolates were haemolytic while indicators of plausible cytotoxicity ( lecithinase, protease and gelatinase production) were in the range of 16.67% to 35.19% indicated that though the isolates were haemolytic they were perhaps less likely to be cytotoxic. Congo Red binding assay for E. coli isolates revealed that majority (88.89%) of the isolates failed to uptake the dye and only few (11.11%) could bind the dye. Results of serotyping revealed a total of 15 different serotypes among the E. coli isolates. More variation was observed among isolates from raw fish samples (12 serotypes) while RTE fish products harboured only 5 different serotypes. Molecular characterization of E. coli isolates revealed that PCR screening of isolates revealed that total 39 (72.22%) samples out of 54 E. coli isolates were positive for stx1 gene and 28 (51.85%) of isolates were positive for stx2 gene. Sources wise, 36 (66.66%) of isolates from raw fish and 3(5.55%) of isolates from RTE fish products were positive for stx1 while and stx2 gene could be detected in 24(44.44%) isolates from raw fish and 4(7.4%) isolates from RTE fish products.Interestingly, about 20% (37.03%) isolates were positive for both stx1 and stx2 genes. Among these multivirulent isolates majority (n=18) belonged to raw fish samples compared to a few (n=2) from RTE fish products. Conclusion:The results of the present study highlighted the possible risks to consumers of fish and fish products in the region that demand action to address this public health concern.

Diversity of antibiotic‐resistant Shiga toxin‐producing Escherichia coli serogroups in foodstuffs of animal origin in northern India

“…The contamination of raw fish with E. coli was observed to be highly common in tropical countries, such as India where raw fish available for human consumption at times were found to be grown in sewage-contaminated farms, or easily contaminated with human or animal feces at crowded markets. This perhaps explains the different E. coli serogroups detected in raw fish in different studies conducted in various regions within Indian subcontinent, the serogroups detected in raw fish in this study was not reported in other studies from India (Costa, 2013;Gupta, Ghatak, & Gill, 2013;Kumar et al, 2004).…”

“…Similarly raw fish isolates vt 1 (four isolates) and vt 2 (three isolates), notably none of the isolates was carrying both of vt 1 and vt 2 genes. Similar results of the carriage of vt 1 and vt 2 (or stx 1 and stx 2 genes) by non-O157 isolates from raw beef (Bai et al, 2016;Sinha et al, 2015;Xia et al, 2010), raw fish (Gupta et al, 2013), raw chicken (Momtaz & Jamshidi, 2013), raw milk (Neher et al, 2015), were reported around the world including Indian subcontinent, in all these reports, no unified association was found between the type of VT gene and the sources of isolates, for example, Sinha et al (2015) found that stx 2 genes were more prevalent in ground beef samples in India, while Bosilevac and Koohmaraie (2011) reported the predominance of stx 1 gene among the STEC isolates in ground beef in the United States. Similar to the results reported in this study, Joris, Pierard, and De Zutter (2011) reported that vt 1 and vt 2 genes were equally harbored by the 18 non-O157 STEC isolates from cattle at slaughter in Belgium.…”

ISOLATION OF Salmonella spp. AND OTHER MEMBERS OF Enterobacteriaceae FROM HORSE MACKEREL (Tra-churus trachurus), SOLD IN PUBLIC MARKETS OF ISTANBUL, TURKEY

“…On the other hand, the dominant isolate in the fish, from public market in Khartoum, Sudan (Yagoub, 2009) and in the catfish, from different markets in Nigeria (Adebayo-Tayo et al, 2012) has been reported as E. coli. Likewise, 48.95% of fish and fish products from Punjab, India (Gupta et al, 2013); and 38.8% of fish and shellfish Mangalore, India (Kumar et al 2005) have been reported as E. coli positive. Ananchaipattana et al, (2012) also reported the highest presence (70%) of E. coli from seafood from retail markets (Open and supermarket) in Thailand.…”

Animal Reservoirs of Shiga Toxin-Producing Escherichia coli

“…Shellfish, due to their filter feeding ability, pose a significant risk to human infection since they can concentrate and retain pathogens (4,130). Numerous studies have reported the recovery of both O157 and non-O157 STEC from the carcass of fish and shellfish offered for sale (131)(132)(133)(134)(135).…”