Evaluation of minimum inhibitory concentration and multi-drug resistance profile of Salmonella isolated from layer poultry farms in kaski district, Nepal
Year: 2025
Type: article
Abstract: Salmonella species are the most prevalent bacterial pathogens infecting poultry. Antibiotics are administered as growth promoters or as a treatment in poultry, raising the prospect of antibiotic resistance. There are very few baseline quantitative studies on antibiotic minimum inhibitory concentrations (MICs) against Salmonella of poultry origin. Thus, this study aims to evaluate the MIC and multidrug resistance (MDR) profile of Salmonella isolated from poultry farms in the Kaski district of Nepal. Laboratory analysis was conducted to determine the minimum inhibitory concentrations of nineteen different antibiotic molecules from various classes against Salmonella spp. isolated from poultry feces. The bacteria were identified using standard protocols and confirmed by polymerase chain reaction for the invA gene. Positively confirmed isolates were subjected to a MIC evaluation assay using the E-test protocol with Ezy MIC Strips following EUCAST guidelines and interpreted accordingly. Out of 610 samples collected, screening using the invA gene for Salmonella confirmed 48 isolates as Salmonella spp., with an overall farm prevalence of 34.43% (n = 61) and a sample-level prevalence of 7.8%. Salmonella spp. displayed the highest resistance to colistin (100%), ciprofloxacin (88%), norfloxacin (72%), ceftriaxone (72%), amoxicillin (77%), ampicillin (66%), erythromycin (66%), cefotaxime (66%), tetracycline (66%), doxycycline (55%), and chloramphenicol (55%). However, amikacin showed higher susceptibility (94%). MIC analysis revealed elevated values for colistin, ciprofloxacin, amoxicillin, ampicillin, ceftriaxone, and doxycycline compared with epidemiological cutoffs. Multidrug resistance was observed in 94% of Salmonella spp. isolates, each showing unique multiple antibiotic resistance (MAR) patterns. The study highlights concern regarding antibiotic resistance in commercial layer farms in the Kaski district, possibly due to excessive antibiotic use by poultry farm owners. Urgent measures are needed to address this public health issue by regulating antibiotic use in the poultry industry in the area.
Source: Animal Reports
DOI: 10.64636/ar.19
Authors: Suresh Nepali, Sharada Thapaliya, Narayan Paudyal, Jeevan Adhikari, Rajesh Gautam
Language: English
Subfield: Food Science
Domain: Life Sciences
Open Access status: hybrid
OpenAlex ID: W4414207997