Extended Spectrum β-Lactamase-Producing Enterobacterales of Shrimp and Salmon Available for Purchase by Consumers in Canada-A Risk Profile Using the Codex Framework

The extended-spectrum β-lactamase (ESBL)-producing Enterobacterales (ESBL-EB) encompass several important human pathogens and are found on the World Health Organization (WHO) priority pathogens list of antibiotic-resistant bacteria. They are a group of organisms which demonstrate resistance to third-generation cephalosporins (3GC) and their presence has been documented worldwide, including in aquaculture and the aquatic environment. This risk profile was developed following the Codex Guidelines for Risk Analysis of Foodborne Antimicrobial Resistance with the objectives of describing the current state of knowledge of ESBL-EB in relation to retail shrimp and salmon available to consumers in Canada, the primary aquacultured species consumed in Canada. The risk profile found that Enterobacterales and ESBL-EB have been found in multiple aquatic environments, as well as multiple host species and production levels. Although the information available did not permit the conclusion as to whether there is a human health risk related to ESBLs in Enterobacterales in salmon and shrimp available for consumption by Canadians, ESBL-EB in imported seafood available at the retail level in Canada have been found. Surveillance activities to detect ESBL-EB in seafood are needed; salmon and shrimp could be used in initial surveillance activities, representing domestic and imported products.

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.

Antimicrobial use and resistance in aquaculture: findings of a globally administered survey of aquaculture-allied professionals

There is limited published information regarding antimicrobial use (AMU) and antimicrobial resistance (AMR) in aquaculture. Our objective was to determine the opinions of aquaculture-allied professionals around the world on the frequency of AMU and AMR in common aquatic species. The study questionnaire included five sections: respondent demographics, extent of AMU in aquaculture, frequency of observations of AMR in aquaculture, AMR monitoring and surveillance and antimicrobial susceptibility testing in various jurisdictions. It was administered in English and Spanish to 604 professionals in 25 countries and with varying expertise in aquaculture. The response rate was 33% (199/604). Over half of the participants had >10 years of experience in aquaculture: 70% (140/199) were involved in fish health/clinical work and their primary experience was with salmon, tilapia, trout, shrimp (including prawn) and/or catfish. Tetracycline use was reported by 28%, 46%, 18%, 37% and 9% of respondents working with catfish, salmon, tilapia, trout and shrimp, respectively. Resistance to tetracycline in one or more species of bacteria was reported as 'frequent-to-almost always' for the same aquaculture species by 39%, 28%, 17%, 52% and 36% of respondents, respectively. 'Frequent-to-almost always' use of quinolone was reported by 70% (32/46) and 67% (8/12) of respondents from the United States and Canada, respectively, where quinolone products are not approved for aquaculture, and extra-label fluoroquinolone use is either prohibited (United States) or discouraged (Canada). Similar frequencies of quinolone use were also reported by the majority of respondents from Europe [70% (7/10)] and Asia [90% (9/10)] where labelled indications exist. This baseline information can be used to prioritize research or surveillance for AMU and AMR in aquaculture.

Prevalence of zoonotic bacteria in wild and farmed aquatic species and seafood: a scoping study, systematic review, and meta-analysis of published research

Increased reliance on seafood has brought to light concerns regarding food safety, but the information to inform risk assessment or surveillance needs is lacking. A scoping study (ScS) was conducted to characterize published research investigating selected zoonotic bacteria and public health topics in various wild and farmed aquatic species and seafood. This was followed by a systematic review (SR) on selected bacteria (Aeromonas spp., generic Escherichia coli, Salmonella spp., and Vibrio spp.) and aquatic species (clams, mussels, oysters, salmon, and shrimp [including prawn]); a meta-analysis (MA) was conducted only at the retail level due to considerable variability among various pathogen/seafood combinations. The ScS revealed the most frequently investigated themes were farm-level prevalence and intervention research for Vibrio spp. and Aeromonas spp. Antimicrobial use (AMU) and the association between AMU and antimicrobial resistance were rarely investigated. The SR indicated a consistent lack of reporting regarding study methodology and results, precluding the use of many studies in and full benefits of MA. MA of Aeromonas, E. coli, and Salmonella prevalence in retail salmon resulted in pooled estimates of 13% (6-27%), 2% (0.1-11%), and 1% (0-5%), respectively. When MA of pathogen/seafood combination resulted in statistically significant heterogeneity (p<0.1), median/range were reported at the region level. The results from our ScS, SR, and MA could be used for better design of future bacteriological surveys of seafood and as inputs for risk assessments or surveillance initiatives in this field.

Infections of Edwardsiella tarda among Brook Trout in Quebec

Acute bacterial septicemia is commonly diagnosed in brook trout Salvelinus fontinalis of Quebec, Canada. The agents most commonly isolated include Aeromonas salmonicida (furunculosis), Aeromonas hydrophila (motile aeromonad septicemia), and Pseudomonas species. Septicemia in brook trout caused by the gram-negative bacterium Edwardsiella tarda was diagnosed for the first time in the province of Quebec from two different fish farms producing stock for fee fishing establishments. Affected fish displayed nonspecific lesions associated with bacterial septicemia including hemorrhages on the gills and viscera and exophthalmia. Stress-associated immunosuppression due to an increase in summer water temperatures and lack of precipitation were considered as primary causes of these disease outbreaks.