PREVALENCE OF COLONIZATION BY Staphylococcus aureus AND METHICILLIN-RESISTANT Staphylococcus aureus (MRSA) AMONG HEALTH CARE PROFESSIONALS AND STUDENTS

Staphylococcus aureus is a commensal organism of the microbiota of the skin and mucosal membranes of the nose in up to one third of human population. Hospitalized patients and health care professionals are at high risk of colonization with health care-associated pathogens, including methicillin-resistant S. aureus (MRSA). This is a worrying factor, since colonization with this organism is associated with increased risk of infection. The aim of this was to determine the prevalence of colonization by S. aureus among health care professionals and students of the teaching hospital of the Universidade Estadual de Londrina (UEL). Health professionals, undergraduate students (nursing, pharmacy, physiotherapy and medicine) and postgraduate students were included in this study after informed consent. Samples were collected from December 2017 to May 2018. Samples from the nasal mucosa were collected with the aid of sterilized swabs that were inoculated into selective media for the isolation and species identification by standard phenotypic methods. The study protocols were approved by the Ethics Committee in Research Involving Human Beings of UEL. The methicillin-resistance was analyzed by cefoxitin disk-diffusion assay according to the Clinical and Laboratory Standards Institute recommendations. Among the 324 individuals (103 health care professionals, 128 undergraduate and 93 postgraduate sutdents) who accepted to participate in the study, the prevalence of S. aureus colonization was 44.75% (145 isolates). Of these, 72.41% (105) and 27.59% of students and professionals, respectively, were colonized. Most colonized individuals (115/145, 79.31%) had been in contact with the hospitalized patients. Among the 105 students, S. aureus colonization was observed in 44.76% (47) postgraduate and 55.24% (58) undergraduate of nursing (14/58, 24.14%), pharmacy (20/58, 34.48%), physiotherapy (6/58, 10.34%) and medicine (18/58, 31.03%). Eighteen isolates (12.41%) out of 145 were classified as MRSA, and they were isolated from six (33.33%) health care professionals, seven (38.89%) undergraduate students, and five (27.78%) postgraduate students. Of 18 MRSA carriers, 15 (83.33%) were in contact with hospitalized patients, being five individuals (33.33%) in each group of health care professionals, undergraduate and postgraduate students. The prevalence of S. aureus found in the study population was substantial, including MRSA carriers. These data are useful for the health care-associated infection control strategies of the University Hospital of Londrina.