Slime producing, heavy metals and antibiotics resistance in Aeromonas hydrophila isolated in Tunisia

Abstract

Aeromonas hydrophila strains isolated from different naturally polluted environments (ten from wastewater, six from bay used for aquaculture, eight from sea coast water and six from fish) were subjected to 13 antibiotics, and to four heavy metals (Copper, Cobalt, Zinc and Mercury) by using agar diffusion and agar dilution methods, respectively. In addition, effect of heavy metals on slime production was also investigated. Results of the antibiotic resistance agreed with those of heavy metals resistance, however, treated wastewater and bay strains were much tolerant than seawater and fish bacteria. The range of metal concentrations that was tolerated in the liquid media yielded information on the tolerance levels of A. hydrophila to different tested concentrations of metals. Copper and zinc were the best tolerated metals. Mercury was the most toxic component for all bacteria. Almost all A. hydrophila produced slime and a small number of strains have changed their morphotype under the heavy metals concentration. Our results have shown that Tunisian aquatic biotopes have a significant proportion of antibiotic and heavy metal resistant to A. hydrophila.

Diversity and Antibiotic Resistance of Aeromonas in Inflow and Outflow Water in Carp Ponds

“…In aquaculture, in order to control and limit spread of bacterial sh infections and diseases different antibiotics are used (Saidi et al 2013;Mulyani et al 2018). Consequently, the widespread abuse of these pharmaceuticals by most farmers for therapeutic and prophylactic reason in aquaculture exerts selective pressures on environmental microbes and may accelerate evolution and dissemination of antibiotic resistance by bacteria (Piotrowska and Popowska 2014;Patil et al 2016, Zdanowicz et al 2020.…”

“…Consequently, the widespread abuse of these pharmaceuticals by most farmers for therapeutic and prophylactic reason in aquaculture exerts selective pressures on environmental microbes and may accelerate evolution and dissemination of antibiotic resistance by bacteria (Piotrowska and Popowska 2014;Patil et al 2016, Zdanowicz et al 2020. The mechanisms of antibiotic resistance among aquatic bacteria are diverse, e.g., (i) reduction of membrane permeability, (ii) drug inactivation, (iii) rapid e ux of antibiotic and (iv) mutation of cellular target (Saidi et al 2013;Kim et al 2015). According to Zhang et al (2009) bacterial resistance to certain antibiotic may be based on more than one of aforementioned mechanisms.…”