Are infectious reproductive pathogens of large ruminants a threat to improving food security? An investigation from Cambodia.

In Cambodia, information on common pathogens causing reproductive losses in cattle and buffalo are lacking, despite there being a need to address livestock health to enhance food security. We analysed stored buffalo (n = 29) and cattle (n = 471) serum samples collected in 2016 using commercially available enzyme-linked immunosorbent assay kits. Antibodies to Neospora caninum, bovine viral diarrhoea virus (BVDV), Leptospira interrogans serovar Hardjo and Brucella abortus were detected in buffalo samples at 79.3% (95% CI 64.6-94.0), 3.4% (95% CI 0-10.0), 0% and 0%, respectively, and in cattle at 4.2% (95% CI 2.4-6.0), 6.4% (95% CI 4.2-8.6), 8.1% (95% CI 5.6-10.6) and 0%, respectively. The high N. caninum seroprevalence in buffalo was associated with increasing age, with buffalo having a 13.1% chance of being seropositive at birth, increasing to 99.4% by age 7 (p = 0.045). This suggests a predominance of horizontal transmission, possibly from exposure to faeces from free-roaming village dogs. Cattle L. interrogans serovar Hardjo seroprevalence was highest in Tbong Khmum province (20.4%) compared to other provinces (p < 0.001), and may be compromising bovine fertility and creating a zoonotic risk for smallholders who may contract leptospirosis from farm work. These high infection rates prompt further research to determine: to what extent these pathogens are linked to the low reproductive efficiency observed in large ruminants in Cambodia, the risk factors to pathogen exposure and appropriate strategies to reduce these risks. Low BVDV and B. abortus exposure is an important observation. Increasing large ruminant livestock trade into the country will require improved biosecurity and disease surveillance to prevent their emergence. An enhanced understanding of the status of infectious reproductive livestock pathogens in Cambodia can assist development projects to make evidence-based strategies to enhance cattle and buffalo health and improve food security.

Antimicrobial resistance in bacteria isolated from peridomestic Rattus species: A scoping literature review.

Rattus spp. may acquire and disseminate antimicrobial resistant bacteria or antimicrobial resistance (AMR) genes. We conducted a scoping review to synthesize available research findings on AMR in Rattus spp. and to describe the size and scope of available literature on AMR epidemiology in Rattus spp. The review was performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analysis extension for Scoping Reviews (PRISMA-ScR). The search focused on scientific peer-reviewed publications focusing on AMR in peridomestic Rattus spp. The review was limited to publications in English available in PubMed, Web of Science and Scopus between 2000 and 2021. The results were summarized descriptively. Thirty-four studies conducted in twenty-one countries were included in this scoping review. Twelve bacterial species with AMR were identified with Escherichia coli and Staphylococcus aureus being the two most commonly reported. The resistant bacteria were isolated from species of peridomestic Rattus spp. in which R. norvegicus and R. rattus were the two most commonly studied. Rats were also found to carry multi-drug resistant (MDR) bacteria including extended-spectrum beta (ß)-lactamase (ESBL), methicillin-resistant Staphylococcus aureus (MRSA), colistin-resistant Enterobacteriaceae (CoRE), and vancomycin-resistant Enterococci (VRE). This scoping review suggests that peridomestic Rattus spp. can carry multiple antimicrobial resistant bacteria, indicating their potential to serve as reservoirs and spreaders of AMR thus posing a threat to human and animal health.

Serotype Diversity and Antimicrobial Resistance Profile of Salmonella enterica Isolates From Freshwater Turtles Sold for Human Consumption in Wet Markets in Hong Kong.

Chelonians are recognized as a source of human salmonellosis through direct contact or consumption of their meat. Freshwater turtles sold for food are widely available in wet markets in Asia. In this pilot study, 50 turtles belonging to three species were randomly sampled from wet markets throughout Hong Kong. The turtles were humanely euthanised and their feces or the colon were sampled for Salmonella culture. The Salmonella isolates obtained were serotyped and examined for phenotypic antimicrobial resistance and the presence of antimicrobial resistance genes. The study reports a high prevalence (42%, 95% CI: 29.4-55.8) and considerable serotype diversity of Salmonella among turtles sold in wet markets. The most common among the 11 serotypes isolated were S. Oranienburg and S. Thompson, which have been reported in turtles previously. The serotype S. Manhattan is reported in chelonians for the first time. Resistance to streptomycin and chloramphenicol was common, despite the latter being banned from aquaculture in mainland China since 2002. Resistance against fluoroquinolones and third-generation cephalosporins which represent first-line treatment options for salmonellosis was also observed. The multidrug-resistance gene cfr is identified for the first time in Salmonella. This is a worrying finding as it indicates an expansion of the cfr reservoir and potential horizontal spread to other bacteria. The results of this study emphasize the need for close surveillance of Salmonella from turtles sold as food and better regulation of turtle farming to safeguard public health and improve animal welfare.