Virulence genes, serobiotypes and antibiotic resistance profile ofEscherichia colistrains isolated from aquaculture and other sources

Abstract

In order to determine the prevalence of pathogenic Escherichia coli, a total number of 155 E. coli isolates from aquaculture, clinical and veterinary sources were screened for seven pathogenic virulence markers and a house-keeping gene by a polymerase chain reaction. The targeted virulence genes included eaeA of enteropathogenic E. coli, elt and est of enterotoxigenic E. coli (ETEC), ipaH of enteroinvasive E. coli, pCVD432 of enteroaggregative E. coli, stx, hlyA and eaeA of shigatoxigenic E. coli (STEC) and Enterohaemorrhagic E. coli. All the isolates were positive for phoA, the house-keeping gene for E. coli. Among the 155 isolates, seven numbers (4.5%) harboured the virulence markers belonging to the pathogenic group ETEC and STEC. The virulent genes detected in these groups were elt, est, hlyA and stx. The sources of these virulence genes were ¢sh (hlyA), shrimp (elt), feeder canal water (hlyA and elt) of aquaculture origin and from diarrhoea a¡ected cow (hlyA, est and stx). The isolates with pathogenic traits belonged to the serogroups O6 or O29 and the remaining could not be typed. They showed resistance to two to four antibiotics out of the 12 antibiotics tested. Biotyping revealed that three isolates belonged to a single biotype (7333) and the remaining isolates were of diverse types. In conclusion, a molecular tool such as PCR proves as more e¡ective tool for detection of this pathogen than the conventional methods. Detection of these emerging pathogens in aquaculture samples warrants for strict adherence to hygienic handling at retail outlets and proper cooking by the consumer before consumption.

Shiga toxigenic and enteropathogenic Escherichia coli in water and fish from pay-to-fish ponds

“…Similar to this study, the low prevalence of eae-positive STEC has been described by several authors (Zschock et al 2000;Irino et al 2005). Alagarsamy et al (2009), who investigated the presence of stx and eae genes in aquaculture systems in India, obtained 128 isolates of E. coli but, unlike the findings of this study, none were positive for stx and eae genes. Wang and Doyle (1998) reported that E. coli O157 can survive in drinking water and in water bodies for several weeks.…”

“…Alagarsamy et al . (), who investigated the presence of stx and eae genes in aquaculture systems in India, obtained 128 isolates of E. coli but, unlike the findings of this study, none were positive for stx and eae genes.…”

Shiga toxigenic, enteroinvasive and enteropathogenic Escherichia coli in fish from experimental fish farm (Layo), Cte dIvoire

“…The presence of these genes is predominant in patients with Hemolytic Uremic Syndrome. Although the detection of strains carrying both eae and Stx genes in aquaculture environments is low (Zschock et al, 2000;Irino et al, 2005;Alagarsamy et al, 2009), it has been detected in the present work and in approximately 7.69% of intestinal fish strains from ponds in northeast of Sao Paulo (Ribeiro et al, 2016). Invasive gene ial was identified only in gills (3.33%) but ipah invasive gene was not detected in othe present study.…”

The use of the so‐called ‘tubs’ for transporting and storing fresh fishery products

“…; however, survival of E. coli O157:H7 after 5 days at 10°C and 15 days at 27°C was reported in seawater (Miyagi et al, 2001;Williams et al, 2007) and detection after 30 days at 10°C was described in lake and river waters (Avery et al, 2008). Fishery and fishery products contamination may arise from faecal contamination of the farming or catching areas and pathogenic E. coli (mainly STEC, but also ETEC and EPEC) have been detected in fresh fish at landing or at market in Brazil, India, South Korea, Algeria and Egypt (Sanath Teophilo et al, 2002;Cardozo et al, 2012;Koo et al, 2012;Murugadas, 2016;Dib et al, 2018;Hussein et al, 2018) as well as in fish in aquaculture settings (Alagarsamy et al, 2010;Siddhnath et al, 2018), fishing ponds (Ribeiro et al, 2016) and fish droppings in aquaponic systems (Wang et al, 2020). Refrigeration temperatures are non-permissive for pathogenic E. coli, the minimum growth temperature being 7-8°C (ICMSF, 1996); however, outbreaks associated with fish or crustacean consumption are occasionally reported (EFSA BIOHAZ Panel, 2013, 2020.…”