Salmonella enterica Serovar Typhimurium and Enteritidis Isolated from Raw Shrimp in Bangladesh: An Investigation Based on Molecular Characteristics, Survival, Virulence, Antibiotic Resistance, and Biofilm Formation Attributes

Abstract

Shrimp is the white gold of Bangladesh, with the second-highest income source from exporting to foreign countries. Contamination with Salmonella spp. is now one of the significant issues for Bangladesh to export. Proper characterization of the salmonella pathogen is thus necessary to avoid undesirable losses due to the rejection of exported shrimp. In Bangladesh, the present condition of raw shrimp contamination with pathogenic Salmonella serovars and their survival/virulence properties was not adequately characterized. In this study, we collected 43 raw shrimps as samples from different farms in Jashore, Khulna, and Sathkhira regions. We then maintained standard cultural and biochemical protocols for isolating Salmonella strains, followed by the molecular identification of particular Salmonella serovars. The standard method for checking its credibility to form biofilm in 0–10% NaCl, tolerate acid/bile stress likewise in the gastrointestinal tract, and resist antimicrobial pressure was performed individually with the particular pathogenic strains. Our results successfully identified eleven Salmonella strains with three typhimurium serovars and three enteritidis serovars, which have biofilm-forming capability up to 4–8% NaCl, acid/bile habituation alike stomach/small intestine of humans, and resistance against necessary antibiotics generally used in treating human and poultry infection signifying the impending danger in the shrimp industry. While previous studies of Bangladesh successfully isolated Salmonella only presumptively, our research focused mainly on molecular characterization of the human Salmonella pathogen along with important survival and virulent attributes, such as biofilm formation, acid/bile tolerance, and antibiotic resistance of selected S. typhimurium and S. enteritidis strains. Further study with more sampling will be necessary to confer the transmission route of the pathogen from the natural reservoir to the shrimp industry.

Antimicrobial Resistance, Virulence Properties and Genetic Diversity of Salmonella Typhimurium Recovered from Domestic and Imported Seafood

“…Other studies key: Beshiru et al [ 17 ] in Nigeria (#S1); Broughton and Walker, [ 44 ] in China (#S2), Das et al [ 45 ] in Bangladesh (#S3); Karp et al [ 46 ] in Taiwan (#S4), Obaidat and Salman [ 47 ] in Jordon (#S5), Wang et al [ 48 ] in USA (#S6), Zhao et al [ 49 ] in USA (#S7). N/A (not applicable): the drug was not used in the study.…”

“…Typhimurium was found to be resistant to amikacin, colistin, and erythromycin ( Table 7 ). Moreover, it possessed intermediate resistance to ciprofloxacin, and kanamycin [ 45 ]. Beshiru et al [ 17 ] in Nigeria stated that S .…”

“…In Nigeria, Beshiru et al [ 17 ] reported multi-antimicrobial resistance for Salmonella Typhimurium; isolated from ready-to-eat shrimp to penicillin, erythromycin, ampicillin, amoxicillin, amoxicillin/clavulanic acid, and doxycycline. Several other investigators also have reported finding multidrug-resistant Salmonella isolates and these have been responsible for both human and animal salmonellosis worldwide [ 11 , 17 , 45 , 53 ]. These findings in addition to other studies including the current study confirmed the necessity for comprehensive worldwide cosmopolitan antimicrobial resistance surveillance ( Table 7 ).…”