Antibiotic resistance in Aeromonas hydrophila and Vibrio alginolyticus isolated from a wound infection: A case report

Aeromonas hydrophila is a motile, nonsporulating, fermentative, facultative, anaerobic, gram-negative bacillus commonly found in fresh water, tap water, soil, and swimming pools.(1,2) Human infections caused by Aeromonas spp. are frequently associated with trauma in the aquatic environment,(3-7) immunosuppression,(7) and chronic disease.(8) beta-Lactam resistance in Aeromonas spp. has been reported.(9) In clinical Aeromonas isolates, genetic properties of the beta-lactamase genes have been characterized.(9-12) Previous reports(9,13) demonstrated that Aeromonas spp. can produce multiple beta-lactamases, including a carbapenem-hydrolyzing metallo-beta-lactamase, which is an important problem for antibiotic treatment. Vibrio alginolyticus is a facultatively anaerobic, gram-negative bacillus with a single polar flagellum for mobility.(14) V. alginolyticus, a halophilic bacterium, is common in coastal waters and sediments all over the world.(15) Human infections caused by V. alginolyticus include ear, soft tissue, and wound infections.(14,16-17) Recent reports(18) showed that 40% of V. alginolyticus isolated from the environment produce beta-lactamases conferring resistance to ampicillin. Antibiotic resistance in V. alginolyticus is a significant problem for wound infections related to the aquatic environment. We describe a wound infection caused by both A. hydrophila and V. alginolyticus related to an aquatic environment. Genetic analysis suggests that microbiologic examination is critical, because these aquatic environment-related isolates had a variety of determinants of antibiotic resistance.