Antimicrobial resistance of Listeria monocytogenes

Listeria monocytogenes is an opportunistic pathogen that causes rare but frequently fatal infections, termed listerioses. In general, strains of L. monocytogenes are susceptible to a wide range of antibiotics, except for the cephalosporins, fluorochinolones and fosfomycin (Hof, 1991). The current therapy of choice is a combination of ampicillin and aminoglycoside, usually gentamicin (Lorber, 1997). In cases when it is not possible to use a beta-lactam antibiotic, second-choice therapy involves the use of an association of trimethoprim with a sulfonamide, such as in co-trimoxazole, in which the more active in the combination seems trimethoprim, synergized by the sulfa compound. Other second line agents for listeriosis include erythromycin and vancomycin (Temple and Nahata, 2000). The first strains of L. monocytogenes resistant to antibiotics were reported in 1988 (Poyart-Salmeron et al. 1990) The present paper reviews the current state of affairs with regard to the resistance of L. monocytogenes isolated from food products and clinical material to different antibiotics, with particular emphasis on those used in the therapy of listeriosis.