Subclinical mastitis (SCM), a silent threat in the dairy sector of Bangladesh poses a significant economic impact and serves as a potential source of infection for healthy cows, hindering efforts to achieve milk self-sufficiency. Despite the importance of this issue, limited research has been conducted on mastitis in Sylhet region of Bangladesh. This study aimed to investigate the molecular prevalence, antimicrobial susceptibility profile and resistant genes detection on pathogens (Staphylococcus aureus, Escherichia coli, and Klebsiella pneumoniae) causing SCM. In a cross-sectional study utilizing convenience sampling, 325 milk samples were collected from apparently healthy dairy cows. Initially, SCM was detected using the modified Whiteside test (MWST) method. Suspected positive samples were then subjected to bacteriological culture and standard biochemical assays, followed by molecular identification through polymerase chain reaction (PCR). Finally, antimicrobial susceptibility testing was conducted on all PCR-positive samples using the Kirby-Bauer disk diffusion method on Mueller-Hinton agar. In the Sylhet district, the prevalence of SCM was 64.92 % (211 out of 325) at the individual animal level and 82.69 % (43 out of 52) at the herd level. Among the SCM-positive animals, S . aureus was found in 31.75 % (67 out of 211) of cases, E . coli in 81.99 % (173 out of 211), and K . pneumoniae in 66.82 % (141 out of 211). K . pneumoniae had the highest prevalence at 60 % in Zakiganj, S . aureus at 45 % in Zakiganj, and E . coli at 72 % in Bishwanath Upazila. Extended spectrum beta lactamase (ESBL) genes bla_TEM, bla_OXA, bla_CTX-M1,bla_CTX-M2,MultiCase_DHA were identified. Additionally, antibiotic resistance genes tet(A), AAC (3)-iv, and Sul1 were also detected. The pathogens exhibited resistance to Penicillins (ampicillin, amoxicillin), Cephems (cefuroxime, ceftazidime), and Tetracyclines (tetracycline). However, all three bacteria were highly sensitive to meropenem, amikacin, gentamicin, ciprofloxacin, and sulfamethoxazole-trimethoprim. These findings highlight the critical need for targeted antimicrobial stewardship and effective control measures to mitigate the impact of SCM on dairy production and animal health in the Sylhet region of Bangladesh.

In the present study, a total of 720 samples were collected from retail raw meat from 13 upazilas in Sylhet District, Bangladesh, of which 225 samples were from cattle meat, 210 samples were from goat meat, and 285 samples were from chicken meat. Salmonella enterica serovars Typhimurium and Enteritidis were screened for extended-spectrum β-lactamase (ESBL) genes using multiplex PCR. Among the 720 samples, Salmonella spp. was detected in 28.06% (202 out of 720) of the samples, with S. Enteritidis and S. Typhimurium were identified in 11.53% (83 out of 720) and 12.22% (88 out of 720) of the samples, respectively. It was found that all Salmonella enterica serovars isolated from cattle meat displayed multidrug resistance (MDR) based on antimicrobial susceptibility testing. Notably, a significant proportion of S. Enteritidis isolates and all S. Typhimurium isolates from goat meat demonstrated complete resistance to multiple drugs (ampicillin, cefuroxime, and ceftazidime). Regarding chicken meat, out of 89 isolates encompassing both S. Typhimurium and S. Enteritidis, 57 isolates (64.04%) exhibited MDR. Additionally, bla_CTX-M-1 exhibited the highest occurrence at 15.69% for S. Typhimurium and 7.89% for S. Enteritidis in chicken meat. Moreover, bla_CTX-M-9 was only detected at 3.92% for S. Enteritidis in chicken meat. Furthermore, bla_OXA had the highest prevalence rate of 19.04% for S. Enteritidis and 25.80% for S. Typhimurium in cattle meat, followed by chicken meat. These findings highlight the urgency for monitoring ESBL-producing Salmonella in retail raw meat and the need for strict measure to manage antibiotic use to prevent the spread of multidrug-resistant and ESBL-producing Salmonella strains, thereby protecting humans and reducing public health risks.

Background: The most prevalent probiotic bacterium employed in the food industry is Lactobacillus because it can produce metabolites with antibacterial capabilities and exhibits hostility towards infections and microorganisms that cause spoilage.Aim: This study set out to identify naturally occurring Lactobacillus and plantaricin (pln EF) coding genes in raw cow milk and to assess the antibacterial potency of isolated Lactobacillus isolates.Methods: Following enrichment in De Man, Rogosa and Sharpe (MRS) broth, single colonies were isolated, and pure colonies were obtained by streaking on MRS agar. The 16S rRNA gene was amplified using polymerase chain reaction (PCR) to confirm the cultural positivity of all isolates. Additionally, the presence of plantaricin was verified by targeting the pln EF gene through PCR.Outcome: Out of the 166 raw milk specimens acquired from cows, 153 (91.17%; CI: 86.98–95.76) were identified as positive for Lactobacillus through both culture and biochemical screening. Subsequently, 121 (72.89%; CI: 65.46–79.49) of the isolates were affirmed to harbour Lactobacillus through PCR analysis. Within this subset, 6 isolates (4.96%; CI: 1.84–10.48) were found to possess the plnEF gene. When exposed to Lactobacillus isolates, Salmonella Typhimurium and Salmonella enterica displayed an average maximum zone of inhibition with a diameter measuring 24 mm. In contrast, Escherichia coli exhibited an average minimum zone of inhibition, featuring a diameter of 11 mm. Additionally, the Lactobacillus isolates demonstrated inhibitory zones against Staphylococcus aureus, Klebsiella pneumoniae and Klebsiella oxytoca, measuring 14, 22 and 19 mm, respectively.Clinical significance: Lactic acid bacteria, particularly Lactobacilli, are plentiful in cow milk and possess broad‐spectrum antibacterial properties.

Antimicrobial resistance (AMR) represents a global health crisis, driven largely by the mobility of resistance determinants through mobile genetic elements (MGEs). These include plasmids, integrons, insertion sequences, transposons, integrative and conjugative elements (ICEs), and prophages, which together facilitate horizontal gene transfer (HGT) across bacterial species and ecosystems. This review aims to provide a comprehensive synthesis of current knowledge on the types, mechanisms, ecological drivers, and impacts of MGEs in the dissemination of antibiotic resistance genes (ARGs). Methods involved critical evaluation of recent genomic, epidemiological, and ecological studies, alongside case studies of clinically significant resistance outbreaks. Findings highlight how MGEs function as hubs for ARG capture, recombination, and stabilization, enabling the emergence of multidrug-resistant (MDR) and extensively drug-resistant (XDR) pathogens. We also explored their interactions with ecological pressures such as antibiotics, heavy metals, and biocides, as well as their role in One Health transmission pathways. The significance of this study lies in linking molecular insights with applied strategies, including genomic surveillance, MGE-targeted inhibitors, phage therapy, and CRISPR-based interventions. Understanding MGEs is essential for designing effective interventions to mitigate AMR and protect global health.

Enterobacteriaceae that produce extended‐spectrum β‐lactamases (ESBLs) can result in severe human infections, contributing to the development of complex diseases. Klebsiella pneumoniae is one of the ESBL‐producing pathogens that helps to set antimicrobial resistance as a major public health problem worldwide. The current study aimed to isolate, identify, and characterize ESBL‐producing K. pneumoniae and their antimicrobial resistance pattern in retail cattle meat samples. A comprehensive set of 225 cattle meat samples was gathered from 13 upazilas within the Sylhet district of Bangladesh. The bacterial isolates were obtained through biochemical and cultural techniques, and the identification of K. pneumoniae was accomplished using polymerase chain reactions (PCRs). Antimicrobial susceptibilities were assessed using disk diffusion in accordance with the Clinical and Laboratory Standards Institute (CLSI, 2020) guidelines. Genes encoding ESBL enzymes were detected by the double‐disk synergy test (DDST) and multiplex PCR. The overall prevalence of Klebsiella spp. was 28.89% (65/225), whereas the positive percentage of K. pneumoniae was 59.2% (29/49) confirmed by PCR. Antimicrobial resistance was observed against 12 antibiotics. According to the phenotypic resistance pattern determined through the disk diffusion method, all isolates (100%) were resistant to ampicillin, amoxicillin, cefuroxime, cefotaxime, and colistin. On the other hand, the highest susceptibility was observed towards gentamicin (97.95%), followed by ciprofloxacin (85.71%), tetracycline (83.67%), and trimethoprim‐sulfamethoxazole (81.63%). Out of the total K. pneumoniae isolates analyzed, ESBL genes were present, and the highest percentage, 82.8% (24/29), tested positive for bla_TEM genes. Interestingly, among the nine ESBL genes, six were identified in K. pneumoniae isolates, except for bla_OXA, bla_{CTX‐M‐grp2}, and MultiCase_DHA. The study’s results reveal the presence of extended‐spectrum β‐lactamase (ESBL)‐producing multidrug‐resistant (MDR) K. pneumoniae in retail cattle meat samples posing a substantial public health threat.

Klebsiella spp. present in the food chain have been of much interest during the last few decades due to their implication in the development of antimicrobial resistance. We determined the prevalence of Klebsiella spp. (Klebsiella pneumoniae and Klebsiella oxytoca) in retail poultry meat, along with their resistance profile against antimicrobials. For the detection of the Klebsiella spp. a total of 285 raw meat samples of retailed poultry were collected and cultured. All positive cultures were screened for Klebsiella spp. by PCR to confirm the identity. Their antimicrobial susceptibility pattern was performed using the disk diffusion technique, whereas the ESBL-coding genes were detected using the multiplex PCR technique. Out of 285 samples, 139 (48.77 %) raw meat samples had Klebsiella spp. While out of 139 identified positive isolates, 99 (34.74 %) isolates were K. pneumoniae, and 13 (4.56 %) were K. oxytoca. Phenotypically, most of the strains were fully (100 %) resistant to ampicillin, amoxicillin, cefuroxime, ceftazidime, and nalidixic acid. Of the β-Lactamase genes that were detected through mPCR, bla _SHV was the dominant gene among the strains K. pneumoniae and K. oxytoca isolates, with percentages of 86.87 % and 76.92 %, respectively. Besides, isolates of K. p n eumoniae harbored 95.96 % (95 % CI: 89.98-98.89) of the tetA gene, whereas the K. oxytoca isolates harbored only 92.31 % (95 % CI: 63.97-99.81) of the tetA gene. Most of the K. pneumonia e and K. oxytoca isolates were found to harbor the streptomycin-resistant gene, strA. These results highlighted significant carriage of multidrug-resistant (MDR) Klebsiella spp. in retail poultry meat, which insinuates that there is a need for a strategic plan in place to curb the dissemination of these multi drug resistant pathogens along the food chain.