Antimicrobial resistance and molecular determination of virulence genes of Aeromonas isolates from clinical patients and hydric samples

This prospective study included all Aeromonas strains isolated from clinical samples from inpatients admitted at the University Hospital of Farhat Hached of Sousse, Tunisia, along with hydric samples, with the aim being to determine (i) the prevalence of Aeromonas infections in patients and (ii) the distribution of virulence-associated genes and (iii) antibiotic resistance among different Aeromonas species. Aeromonas infections seem to be uncommon in the Sousse area of Tunisia, with a total of 81 strains (including those identified biochemically) of Aeromonas found in 54 clinical samples and 27 environmental samples. The biochemically identified Aeromonas species are A. hydrophila (N = 47; 58.1%), A. sobria (19.75%; N = 16), A. caviae (16.04%; N = 13), and A. salmonicida (6.17%; N = 5). The clinical manifestations are primary bacteremia (n = 10, 33.3%), diarrhea (n = 10, 33.3%) and soft-tissue infections (n = 5, 16.6%). A various potential genes encoding haemolysin (hlyA), aerolysin (aerA), cytotonic enterotoxin (alt, ast), cytotoxic enterotoxin (act), Glucose inhibited division gene (gidA), serine protease (sp), enolase (eno), elastase (ela), flagella (fla, lafA), lipase (lip), Outer membrane proteins (ompW), Virulence array protein (vap), Glycerophospholipid-cholesterol acyltransferase (Gcat) have been studied in this work. Amikacin and third-generation cephalosporins were reasonable choices for antimicrobial therapy for the treatment of Aeromonas infections in our region, as 100% and more than 90% of the strains were susceptible, respectively. Determination of the virulence factors contributing to human infections and the mechanism of the host-pathogen interaction in susceptible hosts makes extended studies on these bacteria imperative, and this is the subject of investigation in our group. [GRAPHICS] .