Caracterização molecular e fenotípica de Staphylococcus coagulase-negativo isolados da unidade de terapia intensiva neonatal de um hospital público da cidade de Dourados/MS

Abstract

The coagulase-negative Staphylococcus are gram positive bacterias that can be easely found living harmoniously in the skin of humans, however these microorganisms are among the most frequents causes of nosocomial infections, since they possess the oportunist feature, taking advantage of sick patients. These bacteria can produce biofilm, sticking and colonizing more easily both patients and medical instruments. This scenario worsened after the emergence of methicillin-resistant strains. The aim of this study was to characterize coagulase-negative Staphylococcus strains, isolated from the neonatal intensive care unit of a public hospital in Dourados/MS, that had an oxacillin resistance profile as: the absence of the nucA gene, which confirms that the isolates are not Staphylococcus aureus. The mecA gene, that confers resistance to beta lactam. And the femA gene, that regulates the resistance, rising it. The microplate adhesion technique was also used to semi-quantify the biofilm production of these samples. A total of 33 samples were isolated from august 2016 to august 2017, and their species were determined by the PhoenixTM BD automated system and later confirmed by the PCR technique through the absence of the nucA gene. Of the 33 samples 100% possessed the mecA gene. The femA gene was found in 9% (3) of the samples. The microplate adhesion test detected the biofilm production in 6 (18.1%) of the samples, with only 1 producing strongly, the other 5 producing poorly. The data presented in this study reveal that strains of great pathogenic potential are in circulation, and it is hoped that through this information it will be possible to assist health professionals in creating new means and mechanisms to combat future hospital infections, avoiding expenses, reducing hospitalization time and minimizing mortality.