Assessing Bacteria Load and Antibiotic Resistance in the Gut of Two Fish Species sold at Mindelo Fish Market and Polluted Water in Cabo Verde

Abstract

This research aims to assess the bacteria load and antibiotic resistance in the guts of two species, dobrado (Spicara melanurus), and arenque (Sardinella maderensis), sold at the Mindelo Cabo Verde fish market and its adjacent water. The objectives were to quantify culturable bacteria in the guts of the two fish species. Their resistance to commonly used antibiotics, and the bacterial composition of the water with fish cleaning waste behind Mindelo fish market. Fish samples were randomly collected from six different vendors from the fish market, while water samples were collected from the water behind the market, the immediate pipe that empties the fish waste into the water body, and offshore seawater was used as a negative control. This microbiological study included several steps, namely enumeration, identification using sequencing, and antibiotic susceptibility testing using culture-dependent methods. This study showed that the bacteria load was higher for Spicara melanurus, ranging from 7×104 to 9.7×104 CFU/g, Sardinella maderensis had a load of 3.3×103 to 9.3×103 CFU/g with the water sample from the pipe showing a higher load of 7.7×104, while the fish market had 1.1×104 CFU/ml. The water samples were collected from the main waterbody adjacent to the market with the pipe that empties to it and offshore water as a negative control. The gut microbiota of the fish species and water samples contained a wide variety of antibiotic-resistant bacterial species. Remarkably, resistance to ampicillin was found in eleven out of seventeen isolates tested. Furthermore, bacterial composition analysis revealed the presence of potentially harmful(pathogenic) bacteria in the water behind the fish market. Our study found antibiotic-resistant microbes in the gut and content of two species sold at the Mindelo Fish Market in Cabo Verde, raising concerns about the potential spread of antibiotic-resistant bacterial agents from fish to people.