Abstract

VILLALOBOS DE BASTARDO, Luz Bettina  and  MARTINEZ NAZARET, Rosa Elena. Antimicrobial susceptibility of Listeria spp. isolated of foods during the period 2003-2004. Cumaná, Venezuela. Rev. Soc. Ven. Microbiol. [online]. 2006, vol.26, n.1, pp.31-34. ISSN 1315-2556.

Isolates of L. monocytogenes as well as Listeria spp, has showed natural susceptibility to a large range of antibiotics effective again gram positive bacteria. The posibility of emergency strains resistent to antibiotics was evaluated in vitro in bacteria strains isolated from white chesse and tuna fresh, in Cumaná from February 2003 to February 2003. Samples were collected and processed according to the instructions of the Food and Drugs Administration of the United States, for the isolation of strains. The definitive confirmation was achieved in a gallery API Listeria and for PCR. The profiles of susceptibility and resistance to antibiotics were carried out for the diffusion method in disks. All the listeria strains showed sensibility to the sulphamethoxazole-trimethoprim, gentamicin, chloramphenicol and vancomycin. 13,3% showed resistance to the penicillin G; 26,6% to the ampicillin and 6,7 % to the erythromycin. The resistance level in Listeria monocytogenes and Listeria innocua, became present for erythromycin and ciprofloxacyn, showing a relatively high percentage (20-40%) compared with Listeria welshimeri and Listeria seeligeri which showed  until 50% resistance to the penicillin G and ampicilin.

Keywords : Listeria; susceptibility; antimicrobials; foods.