Vigilância epidemiológica de Staphylococcus aureus resistente a meticilina isolados de um hospital terciário público de Dourados/MS

Abstract

Background: Methicillin-resistant Staphylococcus aureus (MRSA) are frequently associated with multidrug-resistance profiles and a major concern in infections health services. A cross-sectional study was conducted between August/2016 and August/2017, to describe the clinical and molecular characteristics associated MRSA strains isolated from a tertiary hospital located in mid-western Brazil. Methods: Clinical characteristics associated with MRSA bloodstream infections in neonates were investigate with a case control analysis involving 51 patients. Bacterial identification was performed by PhoenixTM system. Antimicrobial susceptibility was determined by broth microdilution. The presence of methicilin-resistance genes (mecA, femA), Panton-Valentine leukocidin encoding gene (pvl) and SCCmec typing was evaluated by PCR and DNA sequencing. Results: A total of 30 methicilin-resistant S. aureus strains were recovered from 30 patients, of which were identified as hospital acquired-MRSA (76,6%) and community-acquired-MRSA (23,4%). The majority of the patients included in the study were neonates (57%). Hyaline membrane syndrome, bronchopulmonary dysplasia, meconium aspiration syndrome, prematurity, long-term hospitalization and use of invasive devices were associated with MRSA bloodstream infections in neonates. PCR amplification and sequencing showed that mecA and femA genes were responsible for resistance to methicllin. Molecular analysis of SCCmec revealed that SCCmectype IV was the most prevalent. Most pvl-positive strains were identified as hospital-acquired Staphylococcus aureus (HA-MRSA), indicating bacterial diversification between HA-MRSA and acquired in the community (CA-MRSA) lineages. Conclusion: this study showed that infected/colonized patients represent reservoirs for horizontal transmission, thus infection control measures are needed to prevent the spread of multidrug resistant strains (MDR) strains in healthcare institutions.