Prevalence and multidrug resistance pattern of Salmonella isolated from resident wild birds of Bangladesh

Multidrug-resistant non-typhoidal Salmonella of public health significance recovered from migratory birds in Bangladesh

Non-typhoidal Salmonella provides an exemplar for the One Health approach as it encompasses public and animal health, food safety, and environmental considerations. The contribution of environmental aspects is currently less well-defined. The purpose of this study was to determine the carriage occurrence of non-typhoidal Salmonella in migratory birds in Bangladesh and assess the potential significance to public and animal health. Cloacal swabs (N = 453) were collected in the years 2018-2020 from Tanguar and Hakaluki Haors, important wetland ecosystems in Northeastern Bangladesh. The prevalence of Salmonella was 13.5% (61 positive swabs). Classical serotyping identified six serovars: Salmonella enterica subsp. enterica serovars Perth, Kentucky, Albany, Infantis, Weltevreden, and Brancaster. Resistance towards 14 antimicrobials was assessed by broth microdilution minimum inhibitory concentration determination and the antimicrobial resistance (AMR) genotype established by whole-genome sequencing. S. Perth and S. Weltevreden isolates were susceptible and harbored no acquired AMR genes. Isolates from the remaining serovars were multidrug resistant, commonly possessing resistance to tetracycline, ampicillin, chloramphenicol, sulfamethoxazole, trimethoprim, and ciprofloxacin. Salmonella resistant to ciprofloxacin meets WHO criteria for priority pathogens. There was excellent concordance between resistance phenotype and the presence of corresponding AMR genes, many of which reside on Salmonella Genomic Islands. High-level ciprofloxacin resistance correlated with the presence of mutations in the chromosomal gyrB and/or parC genes. The S. Kentucky isolates were ST198, a widely distributed multidrug-resistant lineage reported in humans and animals, and constituting an ongoing risk to public health worldwide. We have demonstrated that multidrug-resistant non-typhoidal Salmonella of public health significance can be recovered from migratory birds. A potential for risk can manifest through direct interaction, transmission to food-producing livestock on farms, and dissemination via the long range migratory movements of birds. Risks can be mitigated by measures including continued surveillance and implementation of good farm biosecurity practices.

Characterization and epidemiology of antimicrobial resistance patterns of Salmonella spp. and Staphylococcus spp. in free-ranging rhesus macaque (Macaca mulatta) at high-risk interfaces with people and livestock in Bangladesh

Introduction

Antimicrobial resistance (AMR) is a growing global health threat for humans and animals. Environmental contamination of antimicrobials from human and domestic animal feces has been linked to AMR in wildlife populations, including rhesus macaques. This study aimed to describe the eco-epidemiology of AMR within Salmonella and Staphylococcus species isolated from rhesus macaques.

Methods

We followed macaque groups for 4 h per day (2 days) to observe the direct and indirect contact rate and type between macaques and people and livestock. We collected 399 freshly defecated, non-invasive fecal samples from macaques at seven sites in Bangladesh in January-June 2017. Bacterial isolation and identification were conducted using culture, biochemical characteristics, and polymerase chain reaction (PCR). An antimicrobial susceptibility test (AST) for 12 antimicrobials for each organism was conducted using the Kirby-Bauer disc diffusion method.

Results

The overall prevalence of Salmonella spp. and Staphylococcus spp. in rhesus macaques was 5% (n = 18; 95% CI: 3-7%) and 16% (n = 64; 95% CI: 13-20%), respectively. All the isolated Salmonella spp. and most of the Staphylococcus spp. (95%; 61/64; 95% CI: 86.9-99%) were resistant to at least one antimicrobial. The odds of a fecal sample having antimicrobial-resistant Salmonella spp (OR = 6.6; CI: 0.9-45.8, P = 0.05) and Staphylococcus spp. (OR = 5.6; CI: 1.2-26, P = 0.02) were significantly higher in samples collected at peri-urban sites than those collected at rural and urban sites. Salmonella spp. were most frequently resistant to tetracycline (89%), azithromycin (83%), sulfamethoxazole-trimethoprim (50%), and nalidixic acid (44%). Staphylococcus spp. were found to be highly resistant to ampicillin (93%), methicillin (31%), clindamycin (26%), and rifampicin (18%). Both bacterial species produced colonies with multidrug resistance to up to seven antimicrobials. Direct and indirect contact rates (within 20 m for at least 15 min) and resource sharing between macaques and people were higher in urban sites, while macaque-livestock contact rates were higher in rural sites.

Discussion

The study shows that resistant microorganisms are circulating in rhesus macaque, and direct and indirect contact with humans and livestock might expand the resistant organisms.

Knowledge, Attitudes, and Common Practices of Livestock and Poultry Veterinary Practitioners Regarding the AMU and AMR in Bangladesh

Current evidence indicates that more than half of all antimicrobials are used in the animal food-producing sector, which is considered a significant risk factor for the development, spread, and existence of antimicrobial resistance (AMR) pathogens in animals, humans, and the environment. Among other factors, clinical etiology and the level of knowledge, attitudes, and practices (KAP) of veterinarians are thought to be responsible for inappropriate prescriptions in the animal-source protein production sector in lower-resource settings like Bangladesh. We performed this cross-sectional study to assess factors associated with veterinarians' antimicrobial prescription behavior and their KAP on antimicrobial use (AMU) and AMR in Bangladesh. Exploratory and multivariate logistic models were used to describe an association between knowledge, attitudes, and practices of AMU and AMR and demographic characteristics of veterinarians. The results demonstrated that when selecting an antimicrobial, there was no to minimal influence of culture and susceptibility tests and patients' AMU history but moderate to high influence of the farmer's economic condition and drug instructions among the veterinarians. The results also demonstrated that more than half of the veterinarians had correct KAP regarding AMU and AMR, while the rest had moderate or lower levels of KAP. The factor score analysis revealed that age, level of education, years of experience, gender, and previous training on AMU and AMR were the key influencing factors in their level of KAP. Adjusted logistic regression analysis showed that respondents' age, current workplace, and previous training on AMU and AMR had a positive association with increased KAP. Considering the results, it is imperative to include AMR issues on vet curricula, and to provide post-education training, awareness campaigns, easy access to, and dissemination of AMR resources. Increasing the veterinary services to the outreach areas of the country and motivating veterinarians to follow the national AMR guidelines could be some other potential solutions to tackle the over-prescriptions of antimicrobials.

Knowledge, Attitude, and Practices on Antimicrobial Use and Antimicrobial Resistance among Commercial Poultry Farmers in Bangladesh

Antimicrobial resistance (AMR) has become an emerging health issue globally, posing a threat to zoonotic pathogens and foodborne diseases. In Bangladesh, the poultry sector supplies the majority of the demand for animal-source protein. The irrational and excessive use of antimicrobials (AMU) has been observed in the poultry sector. The development of AMR is associated with many factors, including the knowledge and attitudes of poultry farmers. Therefore, AMR reduction requires intervention from all the stockholders, including the farmers who are considered as end users of antimicrobials. This current research conducted a cross-sectional study to assess the knowledge, attitudes, and practices (KAP) of poultry farmers on AMU and AMR in Bangladesh. We determined the KAP of poultry farmers (broiler and layer farmers) of some selected districts of the country using a tested and paper-based questionnaire. The results demonstrated that most of the respondents have insufficient KAP regarding AMU and AMR. The respondents used a variety of antimicrobials primarily in the treatment of various diseases in poultry. One-third of the farmers did not seek antimicrobials from registered vets. Instead, they depended on others or themselves. The factor score analysis further revealed that the farmers’ demographic and socioeconomic variables were significant factors influencing the KAP. An adjusted logistic regression analysis showed that older farmers with 9–12 years of farming experience and graduate-level education, engaging in medium-sized layer farming, were more likely to have correct KAP on AMU and AMR. Further, farmers from the Cox’s Bazar region showed correct knowledge, whereas farmers of the Chattogram region showed a correct attitude towards AMU and AMR. A Spearman’s rank-order correlation revealed a positive association between knowledge–attitudes and knowledge–practices. The findings of the current investigation provide baseline evidence about the KAP of poultry farmers from low-income resources and offer insights into designing interventions and policies for the use of AMU and AMR in Bangladesh.

Antimicrobial resistance pattern in domestic animal - wildlife - environmental niche via the food chain to humans with a Bangladesh perspective; a systematic review

BACKGROUND

Antimicrobial resistance (AMR) is a growing concern globally, but the impact is very deleterious in the context of Bangladesh. Recent review article on the AMR issue demonstrates the scenario in human medicine; unfortunately, no attempt was taken to address this as One Health issue. The antimicrobial resistance bacteria or genes are circulating in the fragile ecosystems and disseminate into human food chain through direct or indirect ways. In this systematic review we are exploring the mechanism or the process of development of resistance pathogen into human food chain via the domestic animal, wildlife and environmental sources in the context of One Health and future recommendation to mitigate this issue in Bangladesh.

RESULTS

Tetracycline resistance genes were presenting in almost all sample sources in higher concentrations against enteric pathogen Escherichia coli. The second most significant antibiotics are amino-penicillin that showed resistant pattern across different source of samples. It is a matter of concerns that cephalosporin tends to acquire resistance in wildlife species that might be an indication of this antibiotic resistance gene or the pathogen been circulating in our surrounding environment though the mechanism is still unclear.

CONCLUSIONS

Steps to control antibiotic release and environmental disposal from all uses should be immediate and obligatory. There is a need for detailed system biology analysis of resistance development in-situ.

Urban birds: An important source of antimicrobial resistant Salmonella strains in Central Spain

Antimicrobial resistance (AMR) is one of the most important threats of the 21 st century. Wild birds have been described as reservoirs of AMR in different bacterial species, such as Salmonella spp. Privation of food, climate change and overpopulation have forced many wild species to modify their feeding habits, attending urban areas. In this context, the aim of this study was to study Salmonella presence, as well as related AMR in urban birds that inhabit the city and its surroundings. A total of 300 urban birds were sampled for Salmonella detection according to the ISO 6579-1:2017 (Annex D) recommendations, and serotyping was carried out according to the White-Kauffman-Le Minor scheme. Antimicrobial susceptibility was tested following 2013/652/EU Decision guides. Wild birds analysed were positive for Salmonella in 12.3 % of cases, with white storks fed in landfills as the most Salmonella prevalent species (p < 0.05). The most common serovars isolated were zoonotic (S. Enteritidis, S. Typhimurium and S. Typhimurium monophasic variant). From Salmonella isolated strains, 40.5 % were resistant to the most prevalent AMRs found in urban birds were ciprofloxacin (36.4 %), nalidixic acid (36.4 %) and colistin (27.3 %). The scientific community, public administration and population in general should work together to control antimicrobial administration and drug waste management in order to decrease the development and spread of AMR.

A review of Salmonella enterica with particular focus on the pathogenicity and virulence factors, host specificity and antimicrobial resistance including multidrug resistance

Salmonella genus represents the most common foodborne pathogens frequently isolated from food-producing animals that is responsible for zoonotic infections in humans and animal species including birds. Thus, Salmonella infections represent a major concern to public health, animals, and food industry worldwide. Salmonella enterica represents the most pathogenic specie and includes > 2600 serovars characterized thus far. Salmonella can be transmitted to humans along the farm-to-fork continuum, commonly through contaminated foods of animal origin, namely poultry and poultry-related products (eggs), pork, fish etc. Some Salmonella serovars are restricted to one specific host commonly referred to as "host-restricted" whereas others have broad host spectrum known as "host-adapted" serovars. For Salmonella to colonize its hosts through invading, attaching, and bypassing the host's intestinal defense mechanisms such as the gastric acid, many virulence markers and determinants have been demonstrated to play crucial role in its pathogenesis; and these factors included flagella, capsule, plasmids, adhesion systems, and type 3 secretion systems encoded on the Salmonella pathogenicity island (SPI)-1 and SPI-2, and other SPIs. The epidemiologically important non-typhoidal Salmonella (NTS) serovars linked with a high burden of foodborne Salmonella outbreaks in humans worldwide included Typhimurium, Enteritidis, Heidelberg, and Newport. The increased number of NTS cases reported through surveillance in recent years from the United States, Europe and low- and middle-income countries of the world suggested that the control programs targeted at reducing the contamination of food animals along the food chain have largely not been successful. Furthermore, the emergence of several clones of Salmonella resistant to multiple antimicrobials worldwide underscores a significant food safety hazard. In this review, we discussed on the historical background, nomenclature and taxonomy, morphological features, physical and biochemical characteristics of NTS with a particular focus on the pathogenicity and virulence factors, host specificity, transmission, and antimicrobial resistance including multidrug resistance and its surveillance.

Screening of crows and waterfowls for Salmonella and Listeria monocytogenes infection

Background and Aim: Wild birds can carry a number of potential human and animal pathogens. These birds can intrude into human habitats giving the opportunity to transmission of such infection. Therefore, the current study was designed to investigate the role of crows and waterfowls as vectors of Salmonella and Listeria monocytogenes and to compare cultivation methods with direct polymerase chain reaction (PCR) for the detection of infection. Materials and Methods: A total of 200 fecal dropping samples were collected. Salmonella was cultivated by three step method (Universal Pre-enrichment Broth [UPB], Rappaport-Vassiliadis Broth, and Xylose Lysine Desoxycholate agar). The recovered isolates were characterized by biotyping, serotyping, and PCR detection of enterotoxin (stn) gene. The antibiogram pattern of isolates against a panel of 8 antibiotics was recorded. L. monocytogenes was cultivated on UPB, then on Listeria Oxford Agar and Listeria CHROMagar. The recovered isolates were characterized by biotyping and PCR detection of listeriolysin (hylA) gene. Results: The percentages of Salmonella infection in crows and waterfowls were 10 and 20, respectively. The most frequently recovered serovars were Typhimurium, Potengi, Enteritidis, and Kentucky. Antimicrobial susceptibility analysis of Salmonella isolates showed that the resistance rates for gentamicin were the highest (92%), followed by amoxicillin (88%) and cefixime (60%). Resistance to 8 antibiotics was recorded in 60% (15/25) of Salmonella isolates. The percentages of L. monocytogenes infection in crows and waterfowls were 1.3 and 2, respectively. Direct PCR applied to UPB revealed that 12% and 3% of samples were positive for Salmonella and L. monocytogenes, respectively, and there was no significant difference between direct PCR and cultivation method for the detection of infection. Conclusion: The present findings indicate that wild birds can harbor zoonotic enteric pathogens and this necessitates monitoring the epidemiologic status of these pathogens among wild birds and humans and applying the appropriate intervention measures to prevent the spread of infection.