Methicillin- and vancomycin-resistant Staphylococcus aureus in health care workers and medical devices

Introduction: Cross-contamination by Staphylococcus aureusamong patients, professionals and medical supplies in health facilities is a constant concern, leading many researchers to study the prevalence of this pathogen in asymptomatic carriers. Objectives: We investigated the colonization and the antimicrobial susceptibility profile of Staphylococcus spp. on surfaces of medical articles and in professionals from two basic health units in the city of Rio de Janeiro. Materials and methods: Seventy-nine samples resulted in 49 isolates which underwent phenotypic and molecular characterization by polymerase chain reaction (PCR) of coa, mecAand femAgenes. Results: According to the phenotypes, the isolates were identified as S. aureus (n= 35, 71.42%) and coagulase-negative Staphylococcus (CoNS) (n= 14, 28.57%). Among these 14 isolates, 42.85% were methicillin-resistant coagulase negative Staphylococcus (MRCoNS). Among the 35 S. aureus, 31.42% were methicillin resistant (MRSA), and 2.8% were vancomycin resistant, characterized as VRSA. Sixty-eight percent were susceptible to methicillin (MSSA). Genes coa, fem Aand mec Awere amplified from 75.51%, 71.42% and 30.61% of the isolates, respectively. After amplification of the mecAgene, 20.41% were characterized as MRSA, and 10.20% as MRCoNS. The vancomycin-resistant strain was characterized as VRSA after detection of the vanBgene. Conclusion:Our results show a higher frequency of MSSA and MRCoNS among S. aureusand CoNS respectively, colonizing devices and health professionals. However, the already described transfer of the staphylococcal cassette chromosome mec (SSCmec) from MRCoNS to MSSA may alter these results, increasing the frequency of MRSA strains.