Babesiosis is a parasitic vector-borne disease of increasing public health importance. Since the first human case was reported in 1957, zoonotic species have been reported on nearly every continent. ...Zoonotic Babesia is vectored by Ixodes ticks and is commonly transmitted in North America by Ixodes scapularis, the tick species responsible for transmitting the pathogens that also cause Lyme disease, Powassan virus, and anaplasmosis in humans. Predicted climate change is expected to impact the spread of vectors, which is likely to affect the distribution of vector-borne diseases including human babesiosis.
A scoping review has been executed to characterize the global evidence on zoonotic babesiosis. Articles were compiled through a comprehensive search of relevant bibliographic databases and targeted government websites. Two reviewers screened titles and abstracts for relevance and characterized full-text articles using a relevance screening and data characterization tool developed a priori.
This review included 1394 articles relevant to human babesiosis and/or zoonotic Babesia species. The main zoonotic species were B. microti, B. divergens, B. duncani and B. venatorum. Articles described a variety of study designs used to study babesiosis in humans and/or zoonotic Babesia species in vectors, animal hosts, and in vitro cell cultures. Topics of study included: pathogenesis (680 articles), epidemiology (480), parasite characterization (243), diagnostic test accuracy (98), mitigation (94), treatment (65), transmission (54), surveillance (29), economic analysis (7), and societal knowledge (1). No articles reported predictive models investigating the impact of climate change on Babesia species.
Knowledge gaps in the current evidence include research on the economic burden associated with babesiosis, societal knowledge studies, surveillance of Babesia species in vectors and animal hosts, and predictive models on the impact of climate change. The scoping review results describe the current knowledge and knowledge gaps on zoonotic Babesia which can be used to inform future policy and decision making.
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.
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.
Fish aquaculture faces important losses as a result of bacterial resistance to antibiotics. Bacteriophages have proven a useful alternative therapy in other domains, but remain to be tested with ...fish. The interaction between Aeromonas salmonicida HER 1107, bacteriophage HER 110, and brook trout Salvelinus fontinalis was studied in 70‐L aquariums maintained at 9°C. Populations of A. salmonicida (108 colony‐forming units per milliliter) declined by six log units (base 10) in 3 d when bacteriophage HER 110 was introduced in a multiplicity of infection factor of 1. Concentrations of bacteriophages and bacteria in the open water of the aquariums were 2–3 log units lower than those in gravel interstitial water. However, the relative drop in bacterial populations with time was the same in both environments. Addition of the bacteriophage HER 110 delayed by 7 d the onset of furunculosis in brook trout. Further addition of A. salmonicida HER 1107 showed that bacteriophages remained in the aquariums. Mutants of the bacterium were isolated and used as targets for bacteriophage HER 110 and nine other phages. The tests revealed that more than one phage could infect A. salmonicida HER 1107 and that mutants resistant to bacteriophage HER 110 were sensitive to one or more phages. Bacteria resistant to bacteriophage HER 110 had a slower generation time than the original strain, and the success rate of replating in tryptic soy agar (TSA) was very low. More than 25% of the mutants seemed to revert to the original‐strain phenotype after a first replating in TSA. All mutants were sensitive to three or more phages. Finally, stock cultures of 109 plaque‐forming units per milliliter of bacteriophage HER 110 decreased by only one log unit in 80 d when held at 4°C in liquid brain–heart infusion broth culture medium. These results suggest that bacteriophage combinations could be successfully used in preventive programs on fish farms.
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.
The development of resistance to antibiotics commonly used in animal production is an increasing concern for agriculture industries and public health. This study examined the utilisation of proposed ...standard methods for antimicrobial susceptibility testing as described by Alderman and Smith Alderman, D.J., Smith, P. 2001. Development of draft protocols of standard reference methods for antimicrobial agent susceptibility testing of bacteria associated with fish diseases. Aquaculture. 196, 211–243. for oxytetracycline (OTC) and tetracycline (TET). Fifty strains of Aeromonas salmonicida subsp. salmonicida were tested using disk diffusion and MIC techniques, with comparison of incubation periods of 24 and 48 h. The relationship between the MIC and the disk diffusion data was also used to evaluate possible breakpoints for the isolates utilised in this experiment. Susceptible and non-susceptible MIC breakpoints of ≤1 μg/ml and >16 μg/ml, and ≤1 μg/ml and >4 μg/ml fit the datasets for OTC and TET respectively. The calculation of the inhibition zone breakpoints using best-fit line equations yielded values of 15 and 26 mm for OTC and 21 and 28 mm for TET, for the non-susceptible and susceptible breakpoints respectively. The apparent differences in the inhibition zone distributions of the two tetracycline derivatives presented in this study argue for further investigation of breakpoints, with the inclusion of more bacterial strains of intermediate resistance as well as methodology development of susceptibility testing for both oxytetracycline and tetracycline.
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.
PDF
