PROIMI   05436
PLANTA PILOTO DE PROCESOS INDUSTRIALES MICROBIOLOGICOS
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Macrolide plasmid mediated conjugal transference was found in bacteria isolated from Andean Argentinean pristine wetlands
Autor/es:
DIB JR; MARTÍNEZ MA; ORDONEZ O; FARIAS ME
Lugar:
Vienna, Austria
Reunión:
Simposio; 11th International Symposium on Microbial Ecology; 2006
Institución organizadora:
International Society for Microbial Ecology
Resumen:
Background and aims In Argentinean Andes, at high altitude oligotrophic wetlands, we isolated multiple antibiotic-resistant bacteria from freshwater samples (Lagunas Azul, Vilama and Huaca Huasi). We focus this work on macrolide resistances since the MICs found have shown to be particularly high for these antibiotics, as well as if they were somehow transmissible. Methods             Samples were collected during summer seasons. Plasmid DNA was isolated from microorganisms by alkaline lysis method. Isolated strains were evaluated by antibiotic sensitivity tests as recommended by National Committee for Clinical Laboratory Standards. Conjugation assays were performed by standard methods; receptor strain was Bacillus subtilis rifampicin resistant. mefA, ermA and ermB genes primers were used to determine macrolide resistance genes presence. Results Bacteria isolates belonged to Actinomyces, Bacillus and Staphylococcus genera, and two Gram negative bacteria were Acinetobacter johnsonii and Pseudomonas, all with multiple plasmid profiles showing many of them megaplasmids. Isolated bacteria had multiple antibiotic resistances to macrolides, aminoglycosides and penicillines with unexpected high MICs, many of them > 2 mg/mL, for erythromycin (Em) and azithromicyn (Azt). Plasmid mediated conjugal transference to Bacillus in Gram positive was also determined for Azt resistances. No amplification was found with the macrolide genes primers used. Conclusions All isolated bacteria were resistant to multiple antibiotics. High MICs for Azt and Em were found for all bacteria. Azt and Em resistances were transfer to B. subtilis, denoting gene encoded plasmid transferable resistance. As no amplification was observed with the above mentioned primers, they could be unknown genes coding macrolide resistance.