Abstract

VASQUEZ MICHEL, Aneth; GARCIA RADAI, Giovanni  and  LOBO OZUNA, Milton. Asociación de los genes implicados en la codificación de proteina de unión a la penicilina 2a (pbp2a) con la expresión fenotípica de resistencia a la meticilina en cepas De staphylococcus spp.. Cuad. - Hosp. Clín. [online]. 2008, vol.53, n.1, pp.31-37. ISSN 1562-6776.

OBJECTIVE Determining the association between genes involved in the codification of Penicillin Binding Proteins 2A (PBP2A) with the phenotypic expression of methicillin resistance in Staphylococcus spp. strains DESIGN Descriptive cross sectional METHODOLOGY The sensitivity of 67 isolates was determined by means of a phenotypic test (disk diffusion, minimum inhibitory concentration CIM, production of PBP2a) and genotype tests to detect the mecA gene and its regulatory mecR1 and mecI by Polymerase Chain Reaction (PCR). RESULTS From 9 S. aureus resistant strains by disk diffusion 1 was sensitive by CIM, 7 CIM resistant strains were sensitive by disk diffusion. The 7 coagulase negative (CNS) sensitive strains by disk diffusion were resistant by CIM. By production of PBP2a, the results were discordant with the disk diffusion test in 20% and 34%with CIM. The genotype, reveals that, from 60 S.aureus strains 10(17%), and 7 S. coagulase negative strains 4 (57%) carry the mecA gene. From 10 S. aureus mecA positive strains, 5 carry the mecR1 gene and 7 carry the mecI gene. Of the 4 strains of S.coagulase negative mecA positive 2 carry the mecR1 and 2 carry the mecI gene. CONCLUSION There is no association between genotype and phenotype in Staphylococcus spp. methicillin resistant strains, since, the resistance is due to many factors that the classical phenotypic test does not include.

Keywords : Staphylococccus meticilina resistentes (MRS); Staphylococcus aureus; Staphylococcus coagulasa negativo; Proteínas de unión a la Penicilina 2a (PBP2a); genotipo; fenotipo; meticilina; Staphylococcus aureus; coagulase-negative staphylococci; methicillin resistant Staphylococccus (MRS); Penicillin binding Protein 2a (PBP2a); genotype; phenotype,methicillin.

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