Resumen

GALLEGOS, Janneth et al. FREQUENCY OF Listeria spp. IN COASTAL COLOMBIAN CHEESES. Rev.MVZ Cordoba [online]. 2007, vol.12, n.2, pp.996-1012. ISSN 0122-0268.

Objective To determine the frequency of Listeria spp., in coastal fresh cheeses, distributed in popular market places of Montería and Cereté cities. Materials and methods. Keeping in mind the economic importance of this cattle area for Colombia, 217 samples were collected between June and August of 2005, the obtained isolations were identified by presumptive biochemical tests, multiple-PCR-(L1-U1/LF-LR) and biochemical tests for species confirmation. Additionally the frequency of gender species was determined and the antimicrobial resistance of more frequency strains was characterized. Results. Biochemical tests and PCR detected 49 positive isolations for Listeria (22.58%), of which 16.33% (8/49) corresponded to Montería and 24.40% (41/168) to Cereté. Frequency for species was 14.75% for L. ivanovii, 2.30% for L. innocua, 1.84% for L. welshimeri and 1.38% for L. seeligeri, L. monocytogenes was not detected. Only 3/32 stumps of L. ivanovvi (9.38%) showed resistance to penicillin, streptomycin and erythromycin respectively. Conclusions. The results confirm that the coastal cheeses are frequently contaminated with Listeria spp. The presence of L. ivanovii pathogen involved in some cases by opportunist infections in human and L. innocua microorganism used in many food industries as indicator of the grade or sanitization quality; demonstrates that the production conditions and marketing are not good and that the consumption of coastal cheese is not safe. The antimicrobial resistance although lower shows possibilities for the horizontal and/or vertical transmission of resistance genes.

Palabras clave : Listeria; frecuency; cheeses; Córdoba.

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