Prevalence and Antimicrobial Resistance of Bacteria Isolated from Marine and Freshwater Fish in Tanzania

Abstract

This study aimed to determine the prevalence and antimicrobial resistance of bacteria isolated from retail fish and shrimp in Tanzania. A total of 92 fish and 20 shrimp samples were analyzed. Fish samples consisted of 24 Nile tilapia, 24 Nile perch, and 24 red snapper. The isolates were identified by their morphological characteristics, conventional biochemical tests, and analytical profile index test kits. The antibiotic susceptibility of selected bacteria was determined by the disc diffusion method. Out of the 92 samples analyzed, 96.7% were contaminated with 7 different bacterial species. E. coli was the most prevalent bacteria (39%), followed by Klebsiella spp. (28%) and Salmonella spp. (16%). Other species isolated from this study were Staphylococcus spp. (8%), Citrobacter (4%), Shigella spp. (3%), and Pseudomonas spp. (1%). All samples were analyzed for Campylobacter spp.; however, none of the samples tested were positive for Campylobacter spp. Fish from the open-air market were contaminated by six bacterial species: E. coli (40%), Klebsiella spp. (26%), Salmonella spp. (24%), Shigella spp. (6.7%), Citrobacter spp. (6.5%), and Pseudomonas spp. (2%), while E. coli (37%), Klebsiella spp. (33%), Staphylococcus spp. (23%), and Shigella spp. (2%) were isolated in supermarket samples. According to the International Commission on Microbiological Specifications for Foods criteria, 54 (58.7%) and 38 (41.3%) samples were good and marginally acceptable, respectively. E. coli isolates were resistant to penicillin (PEN), erythromycin (ERY), gentamicin (GEN), azithromycin (AZM), and tetracycline (TET), while Salmonella spp. isolates exhibited resistance to gentamicin (CN), tetracycline (TET), penicillin (PEN), and erythromycin (ERY). These results suggest that the presence of these bacteria might cause a health risk/hazard to human beings and may cause disease to susceptible individuals, especially immune-compromised consumers.

Effectiveness of the Organic Acid-Based Antimicrobial Agent to Prevent Bacterial Contamination in Fish Meal

“…However, no ESBL-producing E. coli was recovered from Rohu fish from Myanmar (0%). Similar to other reports, a high prevalence (36.0%) of E. coli compared to other bacteria was found in marine and freshwater fish samples derived from retail markets in Dar es Salaam, Tanzania [ 25 ]. The prevalence of E. coli has also been found in tropical seafood including finfish, shrimp, oysters, and clams.…”

“…Several studies have reported the prevalence of Salmonella from various fish sources, the main ingredient of fish meal production. From the previous report, the highest prevalence of Salmonella was observed from Nile perch (26%), followed by Nile tilapia (24%) and red snapper (12%) collected from the retail market in Dar es Salaam, Tanzania [ 25 ]. Out of 238 fish samples, 57 (24%) collected from Ouagadougou, Burkina Faso showed the positive result for Salmonella detection.…”

Occurrence of Antimicrobial-Resistant Escherichia coli in Marine Mammals of the North and Baltic Seas: Sentinels for Human Health

“…Studies in marine mammals, including different bacterial species, reported the presence of resistant isolates in 35% to 74% of the investigated samples [ 83 , 84 , 86 , 88 ]. No antimicrobial-resistant E. coli was obtained from the fish samples collected in this study, although resistant E. coli has been isolated from different marine fish species in other studies [ 40 , 44 ].…”

“…Once these microbes and antimicrobial residues are released into the environment, natural water bodies themselves may play a certain role in the persistence, emergence, and spread of antimicrobial resistance [ 38 ]. However, antimicrobial-resistant bacteria have also been found in various marine species of all taxa [ 39 , 40 , 41 , 42 , 43 , 44 , 45 ]. For surveillance, apex predators like marine mammals are of specific interest, as they may mirror the burden of antimicrobial resistance in the marine food web as well as the environment.…”

Prevalence and Antimicrobial Resistance of Bacterial Foodborne Pathogens Isolated from Raw Bivalve Molluscs Subjected to Consumption in Poland during a Ten-Year Period

“…Moreover, none of the S. aureus was resistant to gentamicin. In the study conducted by Marijani, [ 66 ], among 16 S. aureus isolates, 31% and 5% were resistant to tetracycline and gentamicin, respectively. However, a resistance to ciprofloxacin, clindamycin, and penicillin was observed in 19%, 13%, and 13% of isolates, respectively.…”