Background: The threat of methicillin-resistant Staphylococcus aureus (MRSA) exists globally and has been listed as a priority pathogen by the World Health Organization. One of the sources of MRSA emergence is livestock and its products, often raised in poor husbandry conditions. There are limited studies in Nepal to understand the prevalence of MRSA in dairy animals and its antimicrobial resistance (AMR) profile. A cross-sectional study was conducted in Chitwan, one of the major milk-producing districts of Nepal, from February 2018 to September 2019 to estimate the prevalence of MRSA in milk samples and its AMR profile. The collected milk samples (n = 460) were screened using the California Mastitis Test (CMT) and positive samples were subjected to microbiological analysis to isolate and identify S. aureus. Polymerase Chain Reaction (PCR) was used to identify the presence of the mecA gene and screen for MRSA. Results: In total, 41.5% (191/460) of milk samples were positive in the CMT test. Out of 191 CMT positive milk samples, the biochemical tests showed that the prevalence of S. aureus was 15.2% (29/191). Among the 29 S. aureus isolates, 6.9% (2/29) were identified as MRSA based on the detection of a mecA gene. This indicates that that 1.05% (2/191) of mastitis milk samples had MRSA. The antibiotic sensitivity test showed that 75.9% (22/29) and 48.3% (14/29) S. aureus isolates were found to be sensitive to Cefazolin and Tetracycline respectively (48.3%), whereas 100% of the isolates were resistant to Ampicillin. In total 96.6% (28/29) of S. aureus isolates were multidrug-resistant (MDR). Conclusions: This study revealed a high prevalence of S. aureus-mediated subclinical mastitis in dairy herds in Chitwan, Nepal, with a small proportion of it being MRSA carrying a mecA gene. This S. aureus, CoNS, and MRSA contaminated milk poses a public health risk due to the presence of a phenotype that is resistant to very commonly used antibiotics. It is suggested that dairy herds be screened for subclinical mastitis and treatments for the animals be based on antibiotic susceptibility tests to reduce the prevalence of AMR. Furthermore, future studies should focus on the Staphylococcus spp. to explore the antibiotic resistance genes in addition to the mecA gene to ensure public health.

Background and Aim: Antimicrobials are extensively used in poultry production for growth promotion as well as for the treatment and control of diseases, including avian pathogenic Escherichia coli (APEC). Poor selection, overuse, and misuse of antimicrobial agents may promote the emergence and dissemination of antimicrobial resistance (AMR) in APEC. This study aimed to assess antimicrobial susceptibility patterns and detect antibiotic resistance genes (ARGs) in APEC isolated from clinical cases of colibacillosis in commercial broiler, layer, and breeder chickens. Materials and Methods: A total of 487 APEC were isolated from 539 across 300 poultry farms in various regions of Nepal. antimicrobial susceptibility patterns was determined using the Kirby-Bauer disk diffusion and broth microdilution methods. The index of AMR, such as multiple antibiotic resistance (MAR) index, resistance score (R-score), and multidrug resistance (MDR) profile, were determined. Polymerase chain reaction was employed to detect multiple ARGs and correlations between phenotypic and genotypic resistance were analyzed. Results: The prevalence of APEC was 91% (487/539). All of these isolates were found resistant to at least one antimicrobial agent, and 41.7% of the isolates were resistant against 8–9 different antimicrobials. The antibiogram of APEC isolates overall showed the highest resistance against ampicillin (99.4%), whereas the highest intermediate resistance was observed in enrofloxacin (92%). The MAR index and R-score showed significant differences between broiler and layers, as well as between broiler breeder and layers. The number of isolates that were R to at least one agent in three or more antimicrobial categories tested was 446 (91.6%) and were classified as MDR-positive isolates. The ARGs were identified in 439 (90.1%) APEC isolates, including the most detected mobilized colistin resistance (mcr1) which was detected in the highest (52.6%) isolates. Overall, resistance gene of beta-lactam (blaTEM), mcr1, resistance gene of sulphonamide (sul1) and resistance gene of tetracycline (tetB) (in broiler), were detected in significantly higher than other tested genes (p < 0.001). When examining the pair-wise correlations, a significant phenotype-phenotype correlation (p < 0.001) was observed between levofloxacin and ciprofloxacin, chloramphenicol and tetracycline with doxycycline. Similarly, a significant phenotype-genotype correlation (p < 0.001) was observed between chloramphenicol and the tetB, and colistin with blaTEM and resistance gene of quinolone (qnrA). Conclusion: In this study, the current state of APEC AMR in commercial chickens is revealed for the first time. This information is useful for the clinical management of disease as well as the creation of policies and guidelines to lower AMR in Nepal’s commercial chicken production. Keywords: antibiotic resistance gene, multiplex PCR, colibacillosis, multiple antibiotic resistance index, mcr1, commercial chicken.

Background and Aim: To combat enteric infections and antibiotic resistance in the poultry industry, researchers seek alternatives such as probiotics, prebiotics, and synbiotics as growth promoters. Synbiotics support probiotic growth through the supply of essential nutrients. The study’s objectives were to assess the most effective delivery methods for synbiotics and evaluate their growth, histomorphometric, and hematological impacts on Cobb-500 broilers. Materials and Methods: Two studies, independently conducted, employed a completely randomized design. One hundred and eighty viable eggs in the first trial were assigned to three groups: Control (T1), sterile water (T2), and synbiotic in sterile water (T3). On the 21st day of hatching, hatchability, day-old body weights, and ileum samples for histomorphometric analysis were recorded. In the second trial, out of 500 viable eggs, 200 eggs were fed in ovo with synbiotics (PoultryStar® sol, Biomin Singapore Pte Ltd, Singapore) on 17.5 days and 300 were set aside without in ovo injection. The treatments were control (T1), in water synbiotic (T2), in ovo synbiotic (T3), combination of in ovo synbiotic and synbiotic in feed (T4), and synbiotic in feed only (T5). On 21 and 42 days, blood, ileum, and visceral organ samples were collected for laboratory analysis. Data on weight gain, daily feed intake, and water consumption were recorded for 42 days. Results: The initial experiment’s results revealed a decrease in hatchability, slight weight increase, and significant intestinal morphological changes with the use of an in ovo synbiotic. Applying synbiotic through various methods in the second trial yielded better growth results, lower blood cholesterol, and significantly longer (p < 0.05) villi on 21 days. Conclusion: Using the in ovo method to administer synbiotics lowered hatchability. Use of synbiotics with any method or in combination enhances growth, ileum structure, dressing yield, feed efficiency, and cholesterol levels in blood. Synbiotics enhance gut health and overall performance in broilers when used through diverse approaches. Keywords: growth performance, gut health, histomorphometry, in ovo, synbiotic.

Campylobacter is the primary cause of food borne gastroenteritis. Moreover, the emergence of multiple drug resistant campylobacters from poultry and pork has produced a potential threat to public health. Research addressing these issues is sparse in Nepal. So, this cross-sectional study aims at determining the prevalence, antibiogram and risk factors of campylobacters from dressed porcine carcass of Chitwan, Nepal.

The poultry sector worldwide faces low productivity and struggles for the control of enteric disorders such as necrotic enteritis (NE), despite its demand. The experiments were carried out on Cobb-500 broilers to assess the effects of various levels of synbiotic (recommended level, 25% and 50% higher than recommended) on growth performance and intestinal lesions. The chicks were divided into three treatment groups and a control group in the initial trial. The second trial included in ovo chicks and normal chicks with varying levels of synbiotic through the feed. Coccivac D2^®, a commercial vaccine, was administered at a concentrated dose (10 times higher) to initiate NE. The results showed that increased levels of synbiotic up to 50% higher than the suggested levels significantly increased weight gain. The feed conversion ratio was noticeably greater during the final 2 weeks. The groups supplemented with synbiotic had reduced scores for necrotic lesions, suggesting protection against NE. Increased synbiotic levels have been shown to improve growth performance and reduce NE. Furthermore, these results highlighted the potential of synbiotic as growth promoter that play a protective role against NE. However, more research is necessary to fully understand the consequences and expenses associated with increased levels of synbiotic in broilers.

Salmonella is a zoonotic foodborne pathogen that affects poultry health and reaches consumers through the food chain via contaminated products. A cross-sectional study was conducted to isolate and identify Salmonella and to detect antibiotic resistance genes in Salmonella isolates from retail meat shops in Chitwan, Nepal. The antimicrobial susceptibility test was carried out using the Kirby–Bauer disc diffusion method. Antibiotic resistance genes were detected by using multiplex polymerase chain reaction (PCR). A total of 216 samples, chicken meat (108) and water (108), were tested for the presence of Salmonella. Out of the 216 samples tested, 38 samples were positive, giving an overall prevalence of 17.59%. A higher prevalence of Salmonella was found in meat samples, 29.62% (32/108), compared with the water samples, 5.55% (6/108), which was statistically significant (p < 0.05). The antibiogram profile showed maximum resistance to doxycycline (88%), followed by tetracycline (86%), erythromycin (79%), ampicillin + sulbactam (76%), ceftriaxone (22%), levofloxacin (21%), gentamicin (18%), chloramphenicol (13%), and amikacin (15%). The prevalence of the tetB gene and ere(A) gene was 23.68% (9/38) and 18.42% (7/38), respectively, and the association was statistically non-significant (p > 0.05). However, mcr1, catA1, and blaTEM genes were not detected. The study recommends integrated surveillance encompassing human health, food safety, and animal health under the ‘One Health’ approach, highlighting the need for effective strategies involving poultry farms, retail meat shops, and consumers to minimize contamination and reduce the transmission of Salmonella along the food chain from primary production to consumption on a global scale.