International Journal of One Health, EISSN: 2455-8931 101 International Journal of One Health Available at www.onehealthjournal.org/Vol.8/No.2/4.pdf RESEARCH ARTICLE Open Access Prevalence and molecular detection of multidrug-resistant Salmonella spp. isolated from eggshells in the local markets of Dhaka, Bangladesh Talal Hossain 1 , Md. Abu Sayem Khan 1 , Md. Firoz Ahmed 2 , and Sabita Rezwana Rahman 1 1. Department of Microbiology, University of Dhaka, Dhaka, Bangladesh; 2. Department of Microbiology, Jahangirnagar University, Savar, Dhaka, Bangladesh. Corresponding author: Sabita Rezwana Rahman, e-mail: sabita_rahman@hotmail.com Co-authors: TH: talal.hossain16@gmail.com, MASK: khan.sayem24@gmail.com, MFA: firoz@juniv.edu Received: 07-04-2022, Accepted: 09-09-2022, Published online: 07-11-2022 doi: www.doi.org/10.14202/IJOH.2022.101-107 How to cite this article: Hossain T, Khan MAS, Ahmed MF, and Rahman SR (2022) Prevalence and molecular detection of multidrug-resistant Salmonella spp. isolated from eggshells in the local markets of Dhaka, Bangladesh, Int. J. One Health, 8(2): 101–107. Abstract Background and Aim: Salmonella spp. are frequently associated with various parts of the egg, including the shell, and cause foodborne outbreaks worldwide. Antibiotic-resistant Salmonella spp. pose serious threats to human and animal health; therefore, preventive measures against these pathogens are important. This study aimed to isolate and characterize Salmonella spp. from eggshell samples from different local markets in Dhaka, Bangladesh. Materials and Methods: Salmonella spp. were recovered from eggshells by enrichment culture and biochemical tests and characterized through molecular amplification of Salmonella-specific genes. Antibiotic sensitivity testing and molecular detection of isolates were performed by disk diffusion method and polymerase chain reaction (PCR), respectively. The invA, fliC, and sdfI genes were used in PCR to identify the genus Salmonella, and the species Salmonella Typhimurium and Salmonella Enteritidis, respectively. Results: The prevalence of Salmonella spp. was recorded as 40%, in which S. Typhimurium was the predominant serotype. PCR analysis revealed that 100%, 59%, and 13.6% of these isolates possessed the invA, fliC, and sdfI genes, respectively. The isolates exhibited multidrug resistance phenotypes, with resistance (95.5%) toward tetracycline, sulfamethoxazole, and clindamycin and sensitivity (86.3%) toward chloramphenicol. Conclusion: The findings of this study reflect the potential of eggs as a reservoir of multidrug-resistant Salmonella spp.; therefore, we recommend the careful handling of eggs to avoid contamination from farm to market. Keywords: antibiotic resistance, eggs, health hazards, poultry industry, Salmonella. Introduction Bacteria in the genus Salmonella are recognized as some of the most widespread foodborne pathogens and have a significant global economic impact [1]. Salmonella account for 93.8 million gastroenteritis cases a year worldwide, which result in 155,000 deaths each year [2]. In 2000, Salmonella spp. was respon- sible for 22 million enteric fever cases that resulted in 200,000 deaths worldwide, mostly in underde- veloped countries [3]. At present, 2463 serotypes of Salmonella have been identified that cause numerous infections in humans and animals [4]. Among them, Salmonella Enteritidis is the most frequently (65%) encountered serotype in non-typhoidal salmonellosis cases, followed by Salmonella Typhimurium (12%) and Salmonella Newport (4%) [5]. Although almost all strains of Salmonella are reported to be pathogenic, the severity of infection depends on the serotype and the susceptibility of the host [6]. A wide variety of foods, including meat, eggs, poultry products, and milk, can act as a vehicle for the transmission of Salmonella spp., and the consumption of these foods, when contaminated with Salmonella, can result in infection, including gastroenteritis and typhoid fever, which constitutes 95% of human cases of salmonel- losis [7]. In the European Union in 2010, eggs and egg products were reported as transmission vehicles in 43.7% of cases of human foodborne outbreaks of salmonellosis [8]. Poultry farming is a profitable business world- wide; considering the total GDP of Bangladesh, the contribution from livestock and poultry is estimated to be 1.47% [9]. In Bangladesh, around 20% of the popu- lation depends on poultry farming as a primary means of livelihood, and around 50% of the population consid- ers it a part-time employment opportunity [10]. Along with the crisis and instability in the poultry industry, infectious diseases such as salmonellosis and avian influenza play a significant role in the achievement of expected growth in this sector. In Bangladesh, the prevalence of Salmonella infections in layer poultry ranges from 28% to 53.2%, suggesting its detrimental effect on the development of the poultry sector [11]. Various Salmonella serotypes have been frequently isolated from poultry farms, indicating the potential of the farm environment as a reservoir for Salmonella Copyright: Hossain, et al. 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