Inappropriate antimicrobial use in food animal farming propels antimicrobial resistance (AMR) that affects all health domains. Colistin is a ‘Reserve’ antibiotic for human treatment to be conserved for multidrug-resistant pathogens; however, it is being used as an animal growth promoter in many developing countries. The evolution of mobilized colistin resistance (mcr) gene-mediated colistin resistance has been reported to be associated with rampant colistin use. This study investigated the current variants of the mcr gene in chicken gut contents in Bangladesh. A cross-sectional study was designed to assess the mcr-1 to mcr-5 genes in 80 fresh poultry droppings from commercial poultry farms and 40 poultry droppings from household farms. DNA was extracted from each poultry dropping using commercial kits (Qiagen GmbH, Hilden, Germany). Real-time quantitative polymerase chain reaction (RT-qPCR) was employed using the qTOWER3 thermal cycler (Analytik Jena GmbH, Jena, Germany) to analyze the mcr gene variants in the extracted DNA. This study observed that 47.5% (57/120) of the samples exhibited the presence of at least one mcr gene out of the five variants investigated. The individual detection rates of the mcr-1, mcr-2, mcr-3, mcr-4, and mcr-5 genes were 42.5% (51/120), 2.5% (3/120), 1.7% (2/120), 5% (6/120), and 9.2% (11/120), respectively. The co-carriage of two or more genes was found in over 10% (10/57) of the samples. The triple occurrence of mcr genes was identified in three samples with the combination of mcr-1+mcr-2+mcr-4, mcr-1+mcr-3+mcr-5, and mcr-1+mcr-4+mcr-5. Overall, a significantly higher number of mcr genes were identified in the commercial farm chicken droppings compared to the household chicken droppings (p = 0.007). The existence of mcr genes in poultry feces in Bangladesh emphasizes the importance of proper poultry waste disposal and good hygiene practices in poultry livestock and its value chain. The potential impact of environmental ARGs should be considered in national and global policy documents. An integrated and combined approach to the One Health concept should be applied in all domains to understand and control the environment’s role in the evolution and transmission of AMR.

Background: Pneumonic pasteurellosis in sheep is an important economical disease in Bangladesh where Pasteurella multocida killed vaccine is prescribed as a preventive measure. Objective: The present research was conducted in 20 non-descript native sheep to estimate antibody titre in response to haemorrhagic septicaemia oil adjuvant vaccine by Pasteurella multocida Indirect Antibody Enzyme Linked Immunosorbent Assay. Methodology: This animal study was performed during January to March 2024 at Bangladesh Livestock Research Institute, Savar, Dhaka, Bangladesh. Twenty non-descript native female lamb born to non-immunized mother aged 3 to 4 months was acclimatized for on station experiment. The blood was collected at up to 63 days with seven days’ interval post vaccination. The vaccine seed molecularly identified for capsular sero-grouping by Polymerase Chain Reaction. Results: The seed bacterium was Pasteurella multocida capsular serotype B. The vaccine generated statistically significant (p<0.05) increased level of antibody titer compared to control group from day 14 that peaked at 42 days and starts to decline after 49 days and onwards. The mean ± standard deviation of antibody titre of treatment group was 1.79±0.33. In Levene teat, there was no variance equality in the samples was found. Conclusion: The oil adjuvant Hemorrhagic Septicemia vaccine produced by Livestock Research Institute; Bangladesh contained killed Pasteurella multocida capsular serogroup B. It was found to generate statistically significant antibody response in vaccinated sheep that started to rise from day 14 and peaked at 42 days. After 49 days, it started its declining trend up to the study period (69 days). Investigation of the field isolates and their subsequent immunoinformatic study could generate better knowledge in designing more effective vaccine candidate that would give durable protection. Bangladesh Journal of Infectious Diseases, June 2024;11(1):3-8

Background: Pneumonia in sheep is a complicated multicausal disease which affects the respiratory system causing increased morbidity and herd mortality rate. The members of Pasteurellaceae family are one of the prime causes of bacterial pneumonia in ruminants. Once infected by these organisms, antimicrobial therapy becomes obligatory. In Bangladesh, causation of pneumonic pasteurellosis and their antibiogram is unknown in sheep which insists the veterinarians to choose empirical antimicrobial therapy. Objectives: This study was undertaken to identify multidrug resistant Pasteurella multocida and Mannheimia hemolytica in sheep suspected with pneumonia. Methodology: The samples of nasal swab and the lungs were collected aseptically. After overnight incubation in Brain Heart Infusion broth, the samples were streaked onto 5.0% sheep Blood Agar to obtain pure colony with characteristic features which were subjected to biochemical tests, polymerase chain reaction (PCR), and antibiogram study against eight antibiotics. Results: A total number of 140 samples were collected of which 120 nasal swabs and 20 lungs were collected aseptically. In total, 16.7% pneumonia cases in sheep were found to be caused by Pasteurella species. Out of 140 samples, 43.57% (61/140) were positive for Mannheimia hemolytica (68.85%) and 19.67% for Pasteurella multocida. The mixed infection by both organisms was 11.48%. The Mannheimia hemolytica (MH) was predominant in lungs (100.0%) and nasal swab samples (18.3%) than Pasteurella multocida (PM) which were 15% and 7.5% respectively. All the isolates were found to be multi-drug resistant where resistance against Penicillin and Ampicillin was 100% for all isolates. The resistance of Mannheimia hemolytica and Pasteurella multocida towards sulfonamide, ceftriaxone, oxytetracycline, gentamicin, and streptomycin were 63.33%, 49.44%, 44.44%. 16.67%, 11.11% and 78.22%, 45.46%, 45.45%, 36.36%, 27.27% respectively. Among all antibiotics tested, Chloramphenicol stands out to be the most effective one (100% sensitive). Conclusion: This study states the first molecular identification of Mannheimia hemolytica and Pasteurella multocida from sheep suspected with pneumonia in Bangladesh and their antibiogram pattern against commonly prescribed antimicrobials. Due to their commensalism nature and wide host coverage, these MDR pathogens warrant judicious use of antibiotics in small ruminants to reduce veterinary public health hazard. Bangladesh Journal of Infectious Diseases, June 2023;10(1):16-23