Transmission Of Zoonotic Pathogens Research Articles

Pathogenicity potential of antimicrobial‐resistant Photobacterium damselae subsp. damselae isolated from maricultured and wild‐caught fish of the southeast coast of India

Antimicrobial resistance and zoonotic pathogen transmission from wild fish to high-density cage-cultured fish are two of the emerging concerns in mariculture. Photobacterium damselae is one of the most destructive bacterial pathogens which is responsible for huge economic loss to the cage culture systems. To investigate the above, both wild-caught and cage-cultured fish were collected from the southeast coast of India. P. damselae subsp. damselae was isolated and their genotypic profiling was done using a specific multiplex polymerase chain reaction. Out of 280 isolates, 61 isolates were confirmed as P. damselae subsp. damselae. The overall prevalence of P. damselae subsp. damselae in wild fish was significantly higher compared with cage-cultured fish. Among the wild fish, parrot fish showed more prevalence when compared with other fish. Around 90% of the identified bacterial isolates were multiple antibiotic-resistant and carried antibiotic resistance genes such as beta-lactam and streptomycin genes. To know the virulence of P. damselae bacteria isolated from wild-caught fish to commercially important cage-cultured fish (cobia and silver pompano) experimentally, a challenging study was carried out. The results revealed that cobia and silver pompano showed 100% and 85% mortality at a bacterial concentration of 3.5 × 104 CFU Fish−1 and 2.75 × 106 CFU Fish−1 respectively. Severe tissue damage and ulceration were also noticed in both fish. In conclusion, the present study found a high rate of AMR in P. damselae subsp. damselae isolated from the fish of the southeast coast of India that exhibit the strong pathogenic potential to cage-cultured fish.

Management strategies emphasizing advanced food processing approaches to mitigate food borne zoonotic pathogens in food system

AbstractFoodborne zoonoses are the most neglected discipline due to a lack of awareness of potential health hazards, standardized detection methods, and identification of infectious host reservoirs. Food is the major carriage vehicle for the transmission of zoonotic pathogens and many outbreaks globally. Resilient surveillance and holistic intervention of effective mitigation strategies at both preharvest (bacteriophages, probiotics, vaccination, micronutrients, breeding, culling), postharvest (advanced food processing, biofilm removal, and disinfectant), retailer and consumer levels can reduce or prevent pathogens and cross‐contamination. Rapid tracking of contamination sources and identification of the route of infection should be implemented using analytical techniques for targeted detection of causative organisms and microbiological risk assessment. An overview elaborating various farm‐to‐fork pathogenic mitigation strategies at different stages of the food chain is presented. However, special emphasis is placed on the application of advanced novel food processing and preservation techniques, such as high‐pressure processing, pulsed light, ultrasound, ultraviolet light, ozone treatment, irradiation and other hurdle technologies for pathogen reduction and food quality assurance. This review will provide an overview of the overall scenario regarding foodborne pathogen–human health interactions and the possible prevention measures that would be helpful for producers, manufacturers, retailers, and consumers for the safer and sustainable development of food products.

Exposure to pesticides and zoonoses during procurement, trade, and consumption of vulture parts: an unexplored threat to human health.

Background: Examination into the origin of SARS-CoV-2 has shed further light on opportunities for broader zoonotic pathogen transmission stemming from the trade in living wildlife and animal parts, and in associated practices. In certain parts of the world (e.g., Africa), various bird species are illegally captured for both subsistence and non-subsistence purposes such as for belief-based use. The latter practice includes rare and declining vulture species and arises from the (relatively recent) belief that directly ingesting certain vulture body parts may impart powers of clairvoyance or bring good fortune. Among a variety of capture methods used by hunters, pesticide-poisoned or nicotine-laced baits are prevalent. In 2020, a mass mortality incident in Guinea Bissau involving over 2000 Critically Endangered Hooded Vultures was linked to belief-based practices, and to the use of a carbamate pesticide. This was to date the highest reported number of vultures killed by pesticide poisoning within a single event. Such deliberate, indiscriminate poisoning is now widely acknowledged within conservation sectors as posing evident threats to vulture species and populations. However, the potential human health repercussions arising from the possibility for zoonotic pathogen transmission (e.g., anthrax, avian H5N1 influenza), and for secondary exposure to the range of toxic substances used to capture and prepare individual birds – whether to hunters, procurers and traders of vulture parts or to consumers – have remained unexplored.Objectives: Our aims are to 1) generate awareness of these practice within human health risk assessment sectors; and 2) generate interest within the human health sector in examining the potential for zoonotic pathogen transmission and toxicity or poisoning risks to people that may stem from these practices.Discussion: We briefly describe human behaviours associated with this belief-driven practice as they relate to potential exposure, and issue a plea for examination of the associated health risks, in collaboration with ongoing conservation and wildlife forensics efforts.

Are foxes (Vulpes spp.) good sentinel species for Toxoplasma gondii in northern Canada?

BackgroundIn changing northern ecosystems, understanding the mechanisms of transmission of zoonotic pathogens, including the coccidian parasite Toxoplasma gondii, is essential to protect the health of vulnerable animals and humans. As high-level predators and scavengers, foxes represent a potentially sensitive indicator of the circulation of T. gondii in environments where humans co-exist. The objectives of our research were to compare serological and molecular assays to detect T. gondii, generate baseline data on T. gondii antibody and tissue prevalence in foxes in northern Canada, and compare regional seroprevalence in foxes with that in people from recently published surveys across northern Canada.MethodsFox carcasses (Vulpes vulpes/Vulpes lagopus, n = 749) were collected by local trappers from the eastern (Labrador and Québec) and western Canadian Arctic (northern Manitoba, Nunavut, and the Northwest Territories) during the winters of 2015–2019. Antibodies in heart fluid were detected using a commercial enzyme-linked immunosorbent assay. Toxoplasma gondii DNA was detected in hearts and brains using a magnetic capture DNA extraction and real-time PCR assay.ResultsAntibodies against T. gondii and DNA were detected in 36% and 27% of foxes, respectively. Detection of antibodies was higher in older (64%) compared to younger foxes (22%). More males (36%) than females (31%) were positive for antibodies to T. gondii. Tissue prevalence in foxes from western Nunavik (51%) was higher than in eastern Nunavik (19%). At the Canadian scale, T. gondii exposure was lower in western Inuit regions (13%) compared to eastern Inuit regions (39%), possibly because of regional differences in fox diet and/or environment. Exposure to T. gondii decreased at higher latitude and in foxes having moderate to little fat. Higher mean infection intensity was observed in Arctic foxes compared to red foxes. Fox and human seroprevalence showed similar trends across Inuit regions of Canada, but were less correlated in the eastern sub-Arctic, which may reflect regional differences in human dietary preferences.ConclusionsOur study sheds new light on the current status of T. gondii in foxes in northern Canada and shows that foxes serve as a good sentinel species for environmental circulation and, in some regions, human exposure to this parasite in the Arctic.Graphical

Virulence Profiles and Antibiotic Susceptibility of Escherichia coli Strains from Pet Reptiles.

Exotic reptiles are increasingly being bred as pets in many countries around the world, including Poland. However, the close contact between reptiles and their owners provides favourable conditions for the transmission of zoonotic pathogens. In this work, we examined E. coli isolates from 67 captive reptiles regarding their virulence, antibiotic susceptibility, phylogenetic affiliation, and genetic diversity. The incidence of E. coli was highest in snakes (51.6%, 16 isolates/31 samples), and slightly lower in turtles (44.4%, 8/18) and lizards (44.4%, 8/18). Genes encoding virulence factors were confirmed in 50% of isolates and the most common were the traT (37.5%, n = 12), fyuA (21.87%, n = 7), and irp-2 (15.62%, n = 5). The majority (71.87%, n = 23) of E. coli isolates were susceptible to all of the antimicrobial substances used in the study. Streptomycin resistance (21.87%, n = 7) was the most frequent, while resistance to other antimicrobial substances was sporadic. One strain (3.12%) was classified as multidrug-resistant. The presence of resistance genes (aadA, tetA, tetB, tetM, and blaTEM) was confirmed in 12.5% (n = 4) of the isolates. The majority (65.6%, n = 21) of E. coli isolates represented the B1 phylogenetic group. (GTG)5-PCR fingerprinting showed considerable genetic variation in the pool of tested isolates. The frequency of E. coli in reptiles is much lower than in mammals or birds. Due to the presence of virulence genes, characteristic of both intestinal pathogenic E. coli (IPEC) and extraintestinal pathogenic E. coli (ExPEC), reptilian strains of E. coli have pathogenic potential, and therefore people in contact with these animals should follow good hygiene practices.

Association of Common Zoonotic Pathogens With Concentrated Animal Feeding Operations

Animal farming has intensified significantly in recent decades, with the emergence of concentrated animal feeding operations (CAFOs) in industrialized nations. The congregation of susceptible animals in CAFOs can lead to heavy environmental contamination with pathogens, promoting the emergence of hyper-transmissible, and virulent pathogens. As a result, CAFOs have been associated with emergence of highly pathogenic avian influenza viruses, hepatitis E virus, Escherichia coli O157:H7, Streptococcus suis, livestock-associated methicillin-resistant Staphylococcus aureus, and Cryptosporidium parvum in farm animals. This has led to increased transmission of zoonotic pathogens in humans and changes in disease patterns in general communities. They are exemplified by the common occurrence of outbreaks of illnesses through direct and indirect contact with farm animals, and wide occurrence of similar serotypes or subtypes in both humans and farm animals in industrialized nations. Therefore, control measures should be developed to slow down the dispersal of zoonotic pathogens associated with CAFOs and prevent the emergence of new pathogens of epidemic and pandemic potential.

Cross-sectional study of ticks in the vulnerable free-living spur-thighed tortoise Testudo graeca (Testudines: Testudinidae) from Morocco

ABSTRACT The spur-thighed tortoise (Testudo graeca L., 1758) is classified as a vulnerable species by the IUCN. In this context, it is important to explore the factors affecting its populations to set up an effective conservation plan. The present study was carried out in seven localities of Morocco with the objective to determine the ticks parasitizing this tortoise and their prevalence in relation to host characteristics and environmental factors. We examined 392 free-living tortoises for the presence of ticks during the spring 2018. A total number of 2238 adult ticks (no immature tick detected) were collected and all identified as Hyalomma aegyptium. Infection with at least one tick was detected in 77.6% ± 6.5 of the total tortoises. The infestation prevalence varied according to localities. Infestation intensity varied from 1.5 to 12, while tick abundance ranged from 0.65 to 12 ticks/tortoise. Male tortoises were more infested than females (P < 0.01) and the infestation was age-dependant. Our statistical result provides that the best model drivers tick parasitism was which included locality and age. Further studies are needed to assess the impact of the high intensity of H. aegyptium infestation on the tortoise’s health status and to assess the potential transmission of zoonotic pathogens.

Seropositivity rates of zoonotic pathogens in small ruminants and associated public health risks at informal urban markets in Zambia

Informal livestock markets are an important source of animal-derived proteins for growing urban populations in countries such as Zambia. In parallel, they can also constitute pathways of zoonotic pathogen transmission to humans. This risk is aggravated by limited disease monitoring and poor control systems with regards to biosecurity and public health. The aim of this study was to investigate the risks for spread of zoonotic diseases in Zambia's two largest informal small ruminant markets, located in Lusaka and Kasumbalesa, through combining seroepidemiology with interviews and observations. In April, May and September 2018, serum samples (n = 237) were collected and analysed for antibodies for the zoonotic pathogens Brucella spp., Coxiella (C.) burnetii and Rift Valley fever virus (RVFV), using commercially available enzyme linked immunosorbent assays (ELISA). In addition, slaughterhouse activities were observed and semi-structured interviews and focus group discussions held with slaughterhouse workers and small ruminant traders, focusing on the handling of animals and meat, and the perceptions of zoonotic disease risks at slaughter and consumption. The study found seropositivity rates of 10.1% (95% confidence interval [CI] 6.60–14.7) for Brucella spp., 5.9% (95% CI 3.27–9.71) for C. burnetii, and 0.8% (95% CI 0.10–3.01) for RVFV. Interviews with value chain members and observations at the slaughterhouse revealed unsanitary procedures and multiple occupational hazards for slaughterhouse workers. This study showed that the Zambian informal small ruminant trade system poses risks to public health, and that these risks are exacerbated by a lack of information about food-borne diseases and how associated risks can be mitigated amongst value chain actors. The results of this study can be used to formulate preventive measures to improve informal meat markets and reduce the risks to public health.

Flooding and abandonment have shaped rat demography across post-Katrina New Orleans

• Disasters can result in conditions that promote transmission of zoonotic pathogens. • Rat demography was examined to assess public health risks in post-Katrina New Orleans. • Prevalence was higher in areas that sustained more severe flood damage and abandonment. • Prevalence reflects disaster response policies that have fortified health disparities.

Physiology and ecology combine to determine host and vector importance for Ross River virus.

Identifying the key vector and host species that drive the transmission of zoonotic pathogens is notoriously difficult but critical for disease control. We present a nested approach for quantifying the importance of host and vectors that integrates species' physiological competence with their ecological traits. We apply this framework to a medically important arbovirus, Ross River virus (RRV), in Brisbane, Australia. We find that vertebrate hosts with high physiological competence are not the most important for community transmission; interactions between hosts and vectors largely underpin the importance of host species. For vectors, physiological competence is highly important. Our results identify primary and secondary vectors of RRV and suggest two potential transmission cycles in Brisbane: an enzootic cycle involving birds and an urban cycle involving humans. The framework accounts for uncertainty from each fitted statistical model in estimates of species' contributions to transmission and has has direct application to other zoonotic pathogens.

Sparse Evidence for Giardia intestinalis, Cryptosporidium spp. and Microsporidia Infections in Humans, Domesticated Animals and Wild Nonhuman Primates Sharing a Farm-Forest Mosaic Landscape in Western Uganda.

Zoonotic pathogen transmission is considered a leading threat to the survival of non-human primates and public health in shared landscapes. Giardia spp., Cryptosporidium spp. and Microsporidia are unicellular parasites spread by the fecal-oral route by environmentally resistant stages and can infect humans, livestock, and wildlife including non-human primates. Using immunoassay diagnostic kits and amplification/sequencing of the region of the triosephosphate isomerase, small ribosomal subunit rRNA and the internal transcribed spacer genes, we investigated Giardia, Cryptosporidium, and microsporidia infections, respectively, among humans, domesticated animals (livestock, poultry, and dogs), and wild nonhuman primates (eastern chimpanzees and black and white colobus monkeys) in Bulindi, Uganda, an area of remarkably high human–animal contact and spatial overlap. We analyzed 137 fecal samples and revealed the presence of G. intestinalis assemblage B in two human isolates, G. intestinalis assemblage E in one cow isolate, and Encephalitozoon cuniculi genotype II in two humans and one goat isolate. None of the chimpanzee and colobus monkey samples were positive for any of the screened parasites. Regular distribution of antiparasitic treatment in both humans and domestic animals in Bulindi could have reduced the occurrence of the screened parasites and decreased potential circulation of these pathogens among host species.

Invasive Burmese pythons alter host use and virus infection in the vector of a zoonotic virus

The composition of wildlife communities can have strong effects on transmission of zoonotic vector-borne pathogens, with more diverse communities often supporting lower infection prevalence in vectors (dilution effect). The introduced Burmese python, Python bivittatus, is eliminating large and medium-sized mammals throughout southern Florida, USA, impacting local communities and the ecology of zoonotic pathogens. We investigated invasive predator-mediated impacts on ecology of Everglades virus (EVEV), a zoonotic pathogen endemic to Florida that circulates in mosquito-rodent cycle. Using binomial generalized linear mixed effects models of field data at areas of high and low python densities, we show that increasing diversity of dilution host (non-rodent mammals) is associated with decreasing blood meals on amplifying hosts (cotton rats), and that increasing cotton rat host use is associated with increasing EVEV infection in vector mosquitoes. The Burmese python has caused a dramatic decrease in mammal diversity in southern Florida, which has shifted vector host use towards EVEV amplifying hosts (rodents), resulting in an indirect increase in EVEV infection prevalence in vector mosquitoes, putatively elevating human transmission risk. Our results indicate that an invasive predator can impact wildlife communities in ways that indirectly affect human health, highlighting the need for conserving biological diversity and natural communities.

Detection and distribution of zoonotic pathogens in wild Norway rats (Rattus norvegicus) from Tehran, Iran

This is the first study on the prevalence of vector-borne zoonotic pathogens found in Rattus norvegicus (R. norvegicus) in urban areas of Tehran, Iran. Serological tests were used to detect IgG antibodies against Coxiella burnetii (C. burnetii) and Rickettsia spp. using a commercial qualitative rat ELISA kit. The frequency of Streptobacillus moniliformis (S. moniliformis) and Bartonella spp. was determined using a conventional PCR method. Molecular detection and characterization of Leptospira spp. were conducted using TaqMan real-time PCR based on lipL32 gene and SecY typing methods. A total of 100 R. norvegicus rats were collected from five regions in Tehran, Iran, and investigated to determine their zoonotic pathogens. S. moniliformis and Bartonella spp. were detected in 23 of 100 (23%) and 17 of 100 (17%) R. norvegicus populations, respectively. The highest prevalence of S. moniliformis and Bartonella spp. with similar frequency rates (n = 6/20; 30%) was seen among the R. norvegicus rats captured from the northern and southern parts of Tehran, respectively. Seroreactivity against C. burnetii and Rickettsia spp. was detected in 4% and 1% of R. norvegicus, respectively. C. burnetii. was identified only in one rat captured from the eastern part of Tehran. Results showed that Leptospira spp. was detected only in two rats, collected from the southern part (n = 2/20; 10%) of Tehran. The secY typing method identified two different Leptospira species including L. interrogans and L. kirschneri. The results showed that urban rats might play an important role in transmission of zoonotic pathogens to humans.

High prevalence and low diversity of chigger infestation in small mammals found in Bangkok Metropolitan parks.

Chiggers are recognized as vectors of scrub typhus disease caused by the bacteria, Orientia tsutsugamushi. The risk of disease exposure is mainly related to chigger bites when humans or animals roam into vector-infested habitats. In big cities, urban public parks could provide areas for the animal-human interface and zoonotic pathogen transmission. The ecology and epidemiology of urban scrub typhus are still poorly understood in Thailand. Small mammals were trapped and examined for chigger infestation in urban public parks across metropolitan Bangkok, Thailand. We found a high prevalence of infestation (76.8%) with surprisingly low diversity. Two chigger species, Leptotrombidium deliense and Ascoschoengastia indica, were identified using morphological characteristics and molecular confirmation. The generalized linear model identified host intrinsic variables (i.e. body mass index) with host density, habitat composition and open field as the extrinsic factors explaining the abundance of chigger infestation. The bacteria O. tsutsugamushi was not detected in chiggers (90 chigger-pooled samples) and animal host tissues (164 spleen samples). However, the existence of chigger vectors calls for the Bangkok Metropolitan Administration and public health authorities to develop a comprehensive scrub typhus monitoring and prevention strategy in the parks and nearby communities.

Antimicrobial drug usage pattern in poultry farms in Nigeria: implications for food safety, public health and poultry disease management.

Good antimicrobial drug stewardship in food‑producing animals boosts productivity and limits transmission of zoonotic pathogens, but the imprudent usage is counterproductive. A nation‑wide survey to determine the pattern of antimicrobial drug usage in poultry was therefore conducted across 12 of the 36 States in Nigeria. The survey was conducted using structured questionnaire designed to elicit information on socio‑demographics, pattern of antimicrobial drug usage and awareness of the consequences of imprudent use of antimicrobials in food‑producing animals, among 2,402 randomly selected poultry farmers. Critically important antimicrobials, belonging to the WHO's lists of 'Highest' and 'High' priority antibiotics, were administered sub‑therapeutically for prophylaxis and growth enhancement purposes. Many diseases that warranted the antimicrobial administration were of viral etiology. Only 64.2% of the farmers administered the drug based on veterinary doctors' prescription. Majority (62.3%) of the farmers did not observe recommended withdrawal period after the drug administration. Awareness of the respondents on consequences of non‑prudent agricultural use of antimicrobials was generally poor. There is need for enlightenment of the farmers on the benefits of prudent agricultural use of antimicrobials. Immediate discontinuation of sale of essential antimicrobials as over‑the‑counter drugs is imperative to safeguard their therapeutic efficacy and curtail spread of antimicrobial‑resistance organisms.

The Contribution of Wildlife Hosts to the Rise of Ticks and Tick-Borne Diseases in North America.

Wildlife vertebrate hosts are integral to enzootic cycles of tick-borne pathogens, and in some cases have played key roles in the recent rise of ticks and tick-borne diseases in North America. In this forum article, we highlight roles that wildlife hosts play in the maintenance and transmission of zoonotic, companion animal, livestock, and wildlife tick-borne pathogens. We begin by illustrating how wildlife contribute directly and indirectly to the increase and geographic expansion of ticks and their associated pathogens. Wildlife provide blood meals for tick growth and reproduction; serve as pathogen reservoirs; and can disperse ticks and pathogens-either through natural movement (e.g., avian migration) or through human-facilitated movement (e.g., wildlife translocations and trade). We then discuss opportunities to manage tick-borne disease through actions directed at wildlife hosts. To conclude, we highlight key gaps in our understanding of the ecology of tick-host interactions, emphasizing that wildlife host communities are themselves a very dynamic component of tick-pathogen-host systems and therefore complicate management of tick-borne diseases, and should be taken into account when considering host-targeted approaches. Effective management of wildlife to reduce tick-borne disease risk further requires consideration of the 'human dimensions' of wildlife management. This includes understanding the public's diverse views and values about wildlife and wildlife impacts-including the perceived role of wildlife in fostering tick-borne diseases. Public health agencies should capitalize on the expertise of wildlife agencies when developing strategies to reduce tick-borne disease risks.

Prevalence of Borrelia burgdorferi and Anaplasma phagocytophilum in Ixodid Ticks from Southeastern Ukraine.

Objectives: Tick-borne diseases have emerged as an increasing medical problem in the world. Being the most prevalent ixodid ticks in Europe, Ixodes ricinus and Dermacentor reticulatus are responsible for transmission of numerous zoonotic pathogens (e.g., human granulocytic anaplasmosis and Lyme borreliosis). Despite their public health significance, studies on the prevalence of tick-borne agents are scare for Eastern Europe. The objective of this study was to examine the prevalence of Anaplasma phagocytophilum, Ehrlichia chaffeensis, and Borrelia burgdorferi sensu lato (B. burgdorferi s. l.) in ixodid ticks from Southeastern Ukraine.Methods: Over a 5-year period (2014–2018), 358 questing and 389 engorged ixodid ticks were collected from Southeastern Ukraine (Zaporizhzhya region). The ticks were identified as Dermacentor marginatus, D. reticulatus, I. ricinus, and Rhipicephalus rossicus. Nucleic acid samples extracted from tick pools were subjected to RT-PCR analyses for A. phagocytophilum, E. chaffeensis, and B. burgdorferi s. l.Results: The examined ixodid ticks tested negative for the aforementioned pathogens with the exception of I. ricinus ticks. For questing I. ricinus ticks, minimum infection rates of A. phagocytophilum and B. burgdorferi s. l. were, respectively, 4.2–7.7% and 8.6–12.7%.Conclusions: These findings will be valuable for medical and veterinary practitioners when risks associated with tick-borne diseases are assessed for southeastern regions of Ukraine.

Rodents harbouring zoonotic pathogens take advantage of abandoned land in post‐Katrina New Orleans

Leptospirosis is a disease that disproportionately affects impoverished urban communities, but is likely to become more prevalent as changing climate alters flooding regimes. The persistence and transmission of the Leptospira pathogen is reliant on small vertebrate animals, predominantly rodents. In this issue of Molecular Ecology, Peterson et al. demonstrate how changes in rodent diversity and abundances across the complex mosaic of abandonment and recovery investment in post-Katrina New Orleans can predict zoonotic infection prevalence. Understanding the ecological conditions that support persistence and transmission of zoonotic pathogens in urban ecosystems, where they are most likely to affect humans, is critical to effective monitoring and prevention.

The effectiveness of biosecurity interventions in reducing the transmission of bacteria from livestock to humans at the farm level: A systematic literature review

Zoonotic bacterial infections are a health hazard for people who are in regular contact with livestock at the farm level. Improved biosecurity can limit zoonotic pathogen transmission within farms. The aim of this review was to summarize the effectiveness of farm‐level biosecurity interventions in reducing bacterial transmission from animals to people who lived, worked in or visited farms. A systematic literature review was conducted using Embase, Ovid Medline and Agris databases, which were searched on 7th of July 2019, limited to English language papers but with no time exclusion criteria. A narrative synthesis was undertaken utilizing the Centre for Reviews and Dissemination approach, reported in accordance with Preferred Reporting Items for Systematic Reviews and Meta‐Analyses guidelines. Risk of bias within and across the included studies was performed using established checklists. Out of 869 studies retrieved through database searches, 11 studies were selected. In addition, three studies were found through study reference lists. Fourteen studies were therefore included in this review. Biosecurity interventions were grouped into five categories: hand washing, sanitization and hygienic measures (six studies); personal protective equipment (five studies); vaccination (two studies); other interventions (e.g. air ventilation flap) (four studies); and routine farm activities (two studies). Across studies that investigated odds of human colonization or infection (three studies), odds were seen to both be increased and decreased through use of tested biosecurity measures. Large confidence intervals that often crossed the threshold of an odds ratio equal to 1 were found. Most of the studies' overall risk of bias was ‘medium risk’ (11 studies), with selection bias domains generally being scored ‘medium risk.’ Biosecurity interventions are potentially beneficial in reducing bacterial transmission from animals to humans. However, more high‐quality evidence is needed to increase certainty in which interventions, in which contexts, are most effective from the human health perspective.

Antimicrobial Usage Factors and Resistance Profiles of Shiga Toxin-Producing Escherichia coli in Backyard Production Systems From Central Chile.

Shiga toxin-producing Escherichia coli (STEC) is a zoonotic pathogen and important cause of foodborne disease worldwide. Many animal species in backyard production systems (BPS) harbor STEC, systems characterized by low biosecurity and technification. No information is reported on STEC circulation, antimicrobial resistance (AMR) and potential drivers of antimicrobial usage in Chilean BPS, increasing the risk of maintenance and transmission of zoonotic pathogens and AMR generation. Thus, the aim of this study was to characterize phenotypic and genotypic AMR and to study the epidemiology of STEC isolated in BPS from Metropolitana region, Chile. A total of 85 BPS were sampled. Minimal inhibitory concentration and whole genome sequencing was assessed in 10 STEC strain isolated from BPS. All strains were cephalexin-resistant (100%, n = 10), and five strains were resistant to chloramphenicol (50%). The most frequent serotype was O113:H21 (40%), followed by O76:H19 (40%), O91:H14 (10%), and O130:H11 (10%). The stx1 type was detected in all isolated strains, while stx2 was only detected in two strains. The Stx subtype most frequently detected was stx1c (80%), followed by stx1a (20%), stx2b (10%), and stx2d (10%). All strains harbored chromosomal blaAmpC. Principal component analysis shows that BPS size, number of cattle, pet and horse, and elevation act as driver of antimicrobial usage. Logistic multivariable regression shows that recognition of diseases in animals (p = 0.038; OR = 9.382; 95% CI: 1.138–77.345), neighboring poultry and/or swine BPS (p = 0.006; OR = 10.564; 95% CI: 1.996–55.894), visit of Veterinary Officials (p = 0.010; OR = 76.178; 95% CI: 2.860–2029.315) and close contact between animal species in the BPS (p = 0.021; OR = 9.030; 95% CI: 1.385–58.888) increase significantly the risk of antimicrobial use in BPS. This is the first evidence of STEC strains circulating in BPS in Chile, exhibiting phenotypic AMR, representing a threat for animal and public health. Additionally, we identified factors acting as drivers for antimicrobial usage in BPS, highlighting the importance of integration of these populations into surveillance and education programs to tackle the potential development of antimicrobial resistance and therefore the risk for ecosystemic health.