Virulence genes in Escherichia coli isolates from commercialized saltwater mussels Mytella guyanensis (Lamarck, 1819)

Escherichia coli O157:H7, a Common Contaminant of Raw Milk from Ecuador: Isolation and Molecular Identification

Escherichia coli (E. coli), especially the Shiga toxin-producing O157:H7 strain, poses severe health risks. In rural Ecuador, raw milk consumption heightens contamination risks. This study analyzed 633 raw milk samples from Pichincha and Manabí to assess E. coli O157:H7 prevalence. The samples were enriched using BHI broth, and then specific culture media were used to isolate E. coli O157:H7. The pathogen in the enriched raw milk was identified, and the isolates were specifically confirmed through the application of a newly designed qPCR assay. The novel qPCR assay demonstrated remarkable sensitivity, capable of detecting up to one copy of genetic material, and specificity (no amplification of other bacteria). An extremely high E. coli O157:H7 prevalence of 0.63 (n = 401) was detected, where the province with the highest number of positive samples was Manabí with 72.8% (n = 225/309) and 54.3% (n = 179/324) for Pichincha. In both provinces, the presence of E. coli O157:H7 contamination exhibited a favorable correlation with small-scale farms and elevated temperatures. This research provides valuable data on the microbiological contamination of E. coli O157:H7 present in raw milk, in addition to an improved method that has been demonstrated to be faster, more sensitive, and more specific than conventional and previously published methods, highlighting the associated risk of food-borne infections and pointing out potential shortcomings in the regulation of agricultural practices and the need for periodic monitoring of bacterial contamination levels with updated methods.

Carbapenem-resistant Escherichia coli from shrimp and salmon available for purchase by consumers in Canada: a risk profile using the Codex framework

Resistance to carbapenems in human pathogens is a growing clinical and public health concern. The carbapenems are in an antimicrobial class considered last-resort, they are used to treat human infections caused by multidrug-resistant Enterobacterales, and they are classified by the World Health Organization as 'High Priority Critically Important Antimicrobials'. The presence of carbapenem-resistant Enterobacterales (CREs) of animal-origin is of concern because targeted studies of Canadian retail seafood revealed the presence of carbapenem resistance in a small number of Enterobacterales isolates. To further investigate this issue, a risk profile was developed examining shrimp and salmon, the two most important seafood commodities consumed by Canadians and Escherichia coli, a member of the Enterobacterales order. Carbapenem-resistant E. coli (CREc) isolates have been identified in shrimp and other seafood products. Although carbapenem use in aquaculture has not been reported, several classes of antimicrobials are utilised globally and co-selection of antimicrobial-resistant microorganisms in an aquaculture setting is also of concern. CREs have been identified in retail seafood purchased in Canada and are currently thought to be uncommon. However, data concerning CRE or CREc occurrence and distribution in seafood are limited, and argue for implementation of ongoing or periodic surveillance.

Co-relationship between Escherichia coli in broiler cellulitis and liver lesions

Pathogenic strains of Escherichia coli may invade the subcutaneous tissue of poultry and cause cellulitis, whilst the pathogen may also cause lesions in internal organs such as the liver. Current paper co-relates Escherichia coli and virulence genes characteristic of Avian Pathogenic Escherichia coli (APEC) in broilers´ cellulitis and liver lesions. One hundred carcasses were retrieved from the production chain in an avian abattoir in the state of Bahia, Brazil, between August 2013 and January 2014, due to detection of cellulitis lesions. Cellulitis and liver samples were retrieved aseptically to quantify E. coli by Petrifilm™ count fast method (3M Company) (AOAC 998.8). Virulent genes iss and iutA were removed from E. coli isolates by Polymerase Chain Reaction (PCR). Escherichia coli was isolated from 82.0% of broilers removed from the production chain and the bacterium was concomitantly detected in cellulitis and liver lesions in 40.0% of broilers. E. coli counts ranged between 1.00 and 4.73 log CFU/g in liver lesions and between 2.00 and 9.00 log UFC/g in cellulitis lesions. Virulent genes iutA and iss were detected in 97.56% and 89.02% of E. coli isolates, respectively. Genotype analysis demonstrated the concomitant amplification of genes iutA and iss in 60.0% (n=40) of samples of cellulitis and liver lesions in which the simultaneous isolation of E. coli occurred. There was a positive and significant co-relationship (r=0.22; p<0.05) between the variables occurrence of E. coli isolated from liver samples and the occurrence of E. coli isolated from cellulitis lesions. There were also positive and significant co-relationships between populations of E. coli from liver isolates and cellulitis lesions (r=0.46; p<0.05) when E. coli isolated in the liver and in cellulitis lesions was detected. Since results showed a relationship between E. coli in cellulitis and liver lesions and possible systemic infection, the occurrence of cellulitis lesions as a criterion for total discarding of carcass may be suggested.

Genotypical characterization of thermotolerant coliforms isolated from food produced by a Solidarity Economic Venture of Bahia (Brazil)

Many Solidarity Economic Venture (SEV) are family farmers who seek to add value to production through artisanal processing, which can lead to food contamination. Thus, this study aimed to genotypically characterize thermotolerant coliforms (TtC) strains from food produced by local agribusinesses of SEV during January to April 2019. Samples from thirteen production units (PU) from the SEV were submitted to a microbiological analysis of thermotolerant coliforms (AFNOR 3M1/2 - 09/89), using a fast count method in Petrifilm™ dishes. The Polymerase Chain Reaction (PCR) technique was used to verify the following virulence genes (VGs) associated with Escherichia coli: stx, typical from enterohemorrhagic E. coli (EHEC); bfpA typical from entheropathogenic E. coli (EPEC) and elt and slt, typical from entherotoxigenic E. coli (ETEC). The results showed that two samples of queijadinha (typical Brazilian candy made with eggs and coconut) and one sample of cassava cake presented characteristic colonies TtC. This way, three strains were isolated in order to perform the PCR technique. However, the genes used in the reaction were not detected in the isolated strains. Therefore, it is suggested that the isolated strains are from E. coli pathotypes with different virulence genes than the ones analyzed belong other types of TtC, such as Enterobacter and Klebsiella. Although the virulence of genes has not been confirmed, the presence of TtC on food indicates hygiene flaws during production and, therefore, measurements to control and prevent contamination should be taken.