Antibiotic Susceptibility Profiles of Listeria monocytogenes Strains Isolated from Food Products and Clinical Samples

Listeria monocytogenes has a ubiquitous distribution in nature and could contaminate food of animal origin, causing severe infections in humans. Till present, little is known about the antibiotic resistance profiles of these strains in Romania. The aim of this study was to determine the antibiotic susceptibility patterns of 37 L. monocytogenes strains isolated from animal derived foods and from clinical samples. Food samples were collected from meat and dairy products, between 2009 and 2013. Clinical samples were collected from patients with septicemia, meningitis/meningo-encephalitis, abortion cases and newborns, hospitalized during April 2010 - April 2013 in three medical institutions from Bucharest: Babes Hospital, Elias Hospital, National Institute of Infectious Diseases (INBI) Matei Bals. All tested isolates exhibited resistance to cephalosporins and nalidixic acid; one strain isolated from boiled shell snails was resistant to trimethoprim/sulfamethoxazole. The resistance to the first choice antibiotic ampicillin in L. monocytogenes strains isolated from severe infections is underlining the need of in vitro antibiotic susceptibility testing of each clinical isolate to establish the efficacy of different antibiotics, as well as of extended epidemiological studies to highlight the resistance profiles of L. monocytogenes strains circulating in our country.