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Background: Shiga toxin‐producing Escherichia coli (STEC) are zoonotic foodborne pathogens and a significant concern with the emergence of antibiotic resistance. Close human contact might have a higher chance of being transmitted to humans from sheep if the sheep population is a potential reservoir of antimicrobial‐resistant STEC. Therefore, this study aimed to examine the sheep population in rural Bangladesh for antimicrobial‐resistant STEC. Methods: We screened 200 faecal samples collected from sheep in three Upazilas from the Chattogram district. Randomisation of sampling was not performed due to the smaller flock size (two to six animals per smallholding). Phenotypically positive E. coli isolates were examined for two Shiga toxin‐producing genes – stx1 and stx2. PCR‐positive STEC isolates were investigated for the presence of antimicrobial resistance (AMR) genes – blaTEM, sul1 and sul2. Results: In total, 123 of the 200 tested samples were confirmed positive E. coli using culture‐based methods. PCR results show 17 (13.8%) E. coli isolates harboured ≥ one virulent gene (stx1 or/and stx2) of STEC. The AMR profile of STEC isolates was determined utilising the disc diffusion method. Of the STEC isolates, 82, 76, 71 and 71% were susceptible to chloramphenicol, gentamicin, ciprofloxacin and ampicillin. In contrast, 47% of isolates were resistant to trimethoprim–sulfamethoxazole, and 41% were resistant to amoxicillin. In addition, six of the tested STEC isolates exhibited the blaTEM gene; eight STEC isolates had the sul1 gene, and the sul2 gene was detected in ten STEC isolates. Conclusion: To our knowledge, this study is the first to reveal a substantial percentage of STEC isolated from sheep in rural Bangladesh harbouring AMR genes. [ABSTRACT FROM AUTHOR]

Background: Salmonella is frequently found in poultry of which only motile serovars have zoonotic significance due to their potential to induce human gastrointestinal infections. Antimicrobial resistance, being a public health concern, the emergence of multidrug‐resistant (MDR) Salmonella serotypes affecting food chain has greater impact worldwide. Aim: Information on circulation of zoonotic Salmonella strains in commercial poultry farm level is limited in many parts of the world. This cross‐sectional study was aimed to investigate the zoonotic Salmonella strains circulating in the broiler farm environment with their detailed antimicrobial resistance profiling. Methods: Pooled faecal samples were collected randomly from commercial broiler farms of Chattogram district, Bangladesh. Standard bacteriological procedure was followed to isolate Salmonella, and identification was confirmed by genus specific polymerase chain reaction (PCR). After phenotypic characterisation of resistance profile against eight antimicrobials by disc diffusion technique, all strains were screened by PCR for some selected resistance genes. Results: Out of the 350 samples, Salmonella was isolated and identified from 86 samples. In antimicrobial sensitivity testing, more than 98.8% isolates showed resistance to ampicillin and 94.2% to tetracycline followed by enrofloxacin (56%) and ciprofloxacin (50%). Notably, 94% isolates were found to be MDR. The results of PCR assays revealed that 81.4% of the isolates were carrying the tetA gene, 19.8% the tetB and 10.47% the tetC gene. The prevalence of the isolates bearing the blaTEM, blaCTX‐M and Sul‐I gene were 95.4%, 7.0 % and 37.2 %, respectively. Conclusion: There is a great risk to secure healthy poultry products due to the circulation of these MDR zoonotic Salmonella [ABSTRACT FROM AUTHOR]

Salmonellosis in poultry is an important disease that seriously impedes the development of the poultry industry. The increased resistance to antimicrobials against Salmonella has been a major public health concern worldwide. We conducted a study from January to June 2016 in and around the Rajshahi district of Bangladesh on the commercial chicken to isolate, identify and characterize poultry‐specific Salmonella, to assess the potential risk factors and to determine the antimicrobial resistance pattern of the isolates. The overall prevalence of Salmonella enterica was 41% (49/120) [95% CI: 31.95%–50.17%] with 41.7% in broiler chicken (25/60) [95% CI: 29.06%–55.12%] and 40% in layer chicken (24/60, 40%) [95% CI: 27.56%–53.46%]. Samples collected from Rajshahi city (OR = 1.37, 95% CI: 0.50–3.73) and Puthia Upazila (OR = 1.51, 95% CI: 0.56–4.12) were more likely to be positive for Salmonella than Charghat Upazila. Salmonella detection was 1.3 times higher in chicken, providing loose feed than those provided ready feed. All the isolates fermented dextrose, maltose and mannitol with the production of acid and gas, but did not ferment sucrose and lactose. The isolates showed catalase, MR, citrate utilization test and TSI agar test positive, but indole and V‐P tests negative. Salmonella isolates were sensitive to ciprofloxacin (90%), gentamycin (80%), amoxicillin (75%), streptomycin (70%), ampicillin (45%) and sulfamethoxazole‐trimethoprim (45%), whereas highly resistant to penicillin (100%) and nalidixic acid (100%) followed by sulfamethoxazole‐trimethoprim (55%), ampicillin (40%) and amoxicillin (25%). Salmonella enterica is endemic in commercial chicken production in Bangladesh with high prevalence. A considerable proportion of Salmonella isolates was found to be resistant to the majority of the common antimicrobial drugs. A good biosecurity system could be effective for the reduction of Salmonella. It is necessary to obtain universal commitments to establish prudent antibiotic use policies. [ABSTRACT FROM AUTHOR]

Background and Aim: The emergence of antimicrobial resistance (AMR) in commensal organism, such as Escherichia coli of food animals, is an alarming issue for global health. It increases the possibility of transmitting AMR determinant(s) to human bacterial pathogens by transferable genetic materials, particularly by plasmids. Hence, it is important to know which resistant genes are being carried by commensal organisms in food chain in a country and their level of temporal loads. As a result, pre-emptive measures can be advocated with an aim to reduce their risks in their primary source of circulation which consequently would benefit the public health. Materials and Methods: Commensal E. coli strains from broiler chickens on randomly selected 30 farms and the farm environments were examined for the frequencies of isolation of resistant strains to oxytetracycline and ciprofloxacin. Five birds were randomly selected from each farm to collect cloacal swab samples (total of 150 samples). Furthermore, a total of 150 environmental samples comprising one each from feed, water, soil, litter, and litter damping site of each farm were screened for the isolation of commensal E. coli strains. Strains thus obtained were initially tested for their resistance to oxytetracycline and ciprofloxacin by Kirby-Bauer disk diffusion method. Oxytetracycline-resistant strains were further screened for the presence of resistance determining genes, namely, tetA, tetB, and tetC by uniplex polymerase chain reactions. Risks associated with the isolation frequency of oxytetracycline- and ciprofloxacin-resistant E. coli were also assessed by univariable logistic regression analysis. Results: The results revealed that all E. coli isolates, regardless of the source of origin, were resistant to oxytetracycline, while 78.4% (95% confidence interval [CI] 69.1-85.5%) showed resistance to ciprofloxacin. All the randomly selected (20) oxytetracycline-resistant strains harbored the tetA gene, whereas tetB and tetC were reported in three and two isolates, respectively. After univariable analysis, only one variable, that is, strain 1 of broiler chickens compared to two other strains was found to be positively associated with the isolation of ciprofloxacin-resistant E. coli (odds ratio 12.75 [95% CI 1.0- 157.1], p=0.047). Conclusion: Resistance emerged against oxytetracycline and ciprofloxacin in commensal E. coli strains circulating in live poultry and farm environments in Bangladesh seems to be very high. Thus, human infection with drug-resistant E. coli strains through food chain will critically compromise the therapeutic measures currently available. [ABSTRACT FROM AUTHOR]

Background and Aim: Staphylococcus aureus is argued as one of the principal organisms responsible for mammary gland infection in lactating goats, causing both clinical and subclinical mastitis. Being highly zoonotic potential, pathogen emergence of methicillin-resistant S. aureus (MRSA) has a significant clinical impact on treatment and management of clinical mastitis. We conducted a cross-sectional study to investigate the prevalence of coagulase-positive S. aureus (CoPS), antimicrobial resistance profile of Staphylococcus spp., prevalence of MRSA, and association between different clinical parameters with CoPS. Materials and Methods: A total of 67 clinical mastitic goats were sampled based on clinical examination and California mastitis test. Standard bacteriological methods were performed to isolate and identify Staphylococcus spp. CoPS were confirmed by nuc gene using polymerase chain reaction (PCR). All staphylococcal isolates were further examined for antimicrobial susceptibility testing by disk diffusion method. MRSA was confirmed based on mecA gene-based PCR. Results: Here, 49 (73.13%; 95% confidence interval [CI], 61.41-82.35) samples were positive for Staphylococcus spp., of which 17 (34.69%; 95% CI, 22.88-48.73) isolates were CoPS and rest of the isolates (32; 65.30%; 95% CI, 51.27-77.12) were identified as coagulase-negative Staphylococcus spp. (coagulase-negative staphylococci [CNS]). Both, CoPS and CNS isolates displayed the highest resistance against tetracycline (76.47% and 75%, respectively) and oxacillin (70.58% and 68.75%, respectively). Notably, all staphylococcal isolates were multidrug-resistant (showed resistance to =3 classes of antimicrobials). mecA gene was found in 6 (8.96%; 95% CI, 3.84-18.52) CoPS isolates indicating MRSA strains. Among different clinical parameters, presence of high body temperature (p<0.05), firm udder consistency (p<0.01), bloodstained milk (p<0.00), and pus in milk (p<0.00) were significantly associated with the presence of CoPS in mastitic caprine milk. Conclusion: To the best of our knowledge, this is the first report of MRSA isolated from clinical caprine mastitis cases in Bangladesh. The findings of this study would help in cautious selection as well as administration of antimicrobials for therapeutic management of mastitic goats. [ABSTRACT FROM AUTHOR]

Aims: Antimicrobial resistance (AMR) spreads not only by pathogenic but also by commensal bacteria, and the latter can become a reservoir for resistance genes. This study was aimed to investigate the AMR patterns along with the presence of mobilized colistin resistance (mcr) genes in commensal Escherichia coli circulating in chickens, farm environments, street foods, and human patients. Materials and Methods: By a cross-sectional survey, isolates obtained from 530 samples were tested for their AMR profiles against 9 antimicrobials. Minimum inhibitory concentration (MIC) of the phenotypically colistin-resistant isolates was determined and screened for a set of mcr genes followed by sequencing of mcr-1 gene in the multidrug-resistant (MDR) isolates. Results: A total of 313 E. coli strains were isolated and confirmed by polymerase chain reaction. Antimicrobial susceptibility testing revealed that about 98% (confidence interval [95% CI] 95–99) of the isolates were MDR, and 58% (95% CI 52–63) isolates exhibited resistance to colistin. MIC values of colistin against the isolates ranged from 4 to 64 mg/L. Except for human patients, 20.4% colistin-resistant isolates from other sources of isolation had mcr-1 gene. Conclusions: There is abundance of commensal MDR E. coli strains with the acquisition of mcr-1 gene circulating in chickens and farm environments in Bangladesh. [ABSTRACT FROM AUTHOR]