ABSTRACT
Infecções hospitalares por Methicillin-Resistant S. aureus (MRSA) e Methicillin-Resistant Coagulase-Negative Staphylococci (MRCoNS) estão entre as mais frequentes mundialmente, justificando um aumento significativo no uso de vancomicina. Com o objetivo de avaliar a presença de estafilococos resistentes aos glicopeptídeos em pacientes em uso terapêutico desse antimicrobiano, internados no Hospital de Clínicas da Universidade Federal de Uberlândia, Uberlândia MG, foi realizado um estudo longitudinal prospectivo incluindo 41 pacientes, 21 adultos e 20 crianças, entre dezembro de 2000 e março de 2002. O monitoramento microbiológico foi realizado por meio de swabs coletados a partir da cavidade bucal e reto e cultivo primário em Ágar Manitol Salgado acrescido de 6 mg/mL de oxacilina. Amostras selecionadas foram testadas quanto à sensibilidade aos glicopeptídeos pelas técnicas de gel difusão e diluição em ágar e a análise de heterorresistência, pela semeadura utilizando inóculo correspondente à escala 0,5 de McFarland (108 UFC/mL) e análise do perfil populacional. Um único paciente, nefropata em programa de hemodiálise apresentou-se colonizado com uma amostra do fenótipo Vancomycin-Intermediate S. aureus (VISA) (CIM = 8 miug/mL) e em doze, foram isoladas amostras de estafilococos heterorresistentes, correspondendo oito hVISA e quatro hVICoNS. O estudo do perfil populacional, confirmou a presença de subpopulações de células resistentes, sendo seis hVISA e duas hVICoNS. A presença de amostras heterorresistentes à vancomicina pode representar um risco potencial no futuro.
Methicillin-resistant Staphylococcus aureus (MRSA) and Methicillin-resistant Coagulase-negative Staphylococci (MRCoNS) are among the most frequent hospital infections around the world, and are associated with a significant rise in the use of vancomycin. In order to assess the presence of staphylococci resistant to glycopeptides in patients taking this antibiotic in Uberlândia Federal University Hospital, Uberlândia (MG, Brazil), a prospective longitudinal study of 41 patients (21 adults and 20 children) was performed between December 2000 and March 2002. Microbiological monitoring was carried out by means of swabs collected from the oral cavity and rectum, screened by culturing in Salt Mannitol Agar plus 6 ?g/mL oxacillin. Selected samples were tested for susceptibility to glycopeptides, by the techniques of gel diffusion and dilution in agar, and for heteroresistance, by seeding with an inoculum at a density of 0.5 on the McFarland scale (108 CFU/mL) and performing a population analysis profile (PAP). A single nephropathy patient was colonized with a strain of vancomycin intermediate S. aureus (VISA) phenotype (MIC = 8 miug/mL). In twelve patients, heteroresistant staphylococci were isolated, corresponding to eight hVISA and four hVICoNS. The PAP study confirmed the presence of six hVISA and two hVICoNS. The presence of heteroresistant vancomycin samples may pose a potential risk in the future.
Subject(s)
Humans , Male , Female , Child , Adult , Cross Infection , Staphylococcal Infections , Vancomycin ResistanceABSTRACT
The hospital environment, especially surfaces, represents a secondary reservoir for pathogens such as Staphylococcus aureus. The present study was carried out at the Hospital de Clínicas da Universidade Federal de Uberlândia (HC-UFU) in Brazil, from January to August 2004, with the aim of qualitatively and quantitatively assessing the presence of S. aureus on surfaces touched by hands (bed rail, bedside table and door handle), on the floor and in the air, in wards where the patients were infected or not infected with this organism. Twenty-six wards with at least one infected patient and 26 wards with uninfected patients were investigated. Surfaces and air were sampled during bedmaking, by means of sterile 10cm2 adhesive tapes and 90mm-diameter exposed culture plates, respectively. Cultures were carried out on Egg Yolk Salt Agar, containing 7.5% NaCl and 1% egg yolk, and colonies identified by lecithinase and coagulase tests and Gramstain. About 50% of the wards were S. aureus contaminated, without significant differences between the groups (46.1% in the infected patient wards versus 53.8% in controls); the correlation between counts of the pathogen on the surfaces and in the air was 66.7%. Inspite of the fact that these bacteria were frequently present in the assessed wards, the microbial density waslow (less than 1 CFU/cm2). The association between environmental contamination and the epidemiology of S. aureus nosocomial infections is complex and thus further investigations are needed to reach a better understanding of this relationship.