Análise de portadores assintomáticos de Staphylococcus aureus no Hospital Universitário de Brasília

AUTOR(ES)
DATA DE PUBLICAÇÃO

2008

RESUMO

Staphylococcus aureus is a pathogen associated with high rates of mortality and morbidity, capable of producing infections in various tissues of the human body. His ability to acquire resistance to antibiotics makes it a dangerous infectious agent in the hospital environment. The purpose of this work was to survey the incidence of asymptomatic carriers of S. aureus resistant (MRSA) and susceptive (MSSA) to methicillin in the University Hospital of Brasília (HUB), and the development of procedures for molecular identification of MSSA and MSRA strains. In total 327 samples were collected nasal and sub-nail of individuals related to the HUB. These samples were divided into three groups: students (medicine, nursing and dentistry), medical staff (nurses, nursing assistants and doctors) and the Technical Group (employees who do not have contact with patients). Were also collected 48 samples from patients previously identified as MRSA by HUB and 136 samples from individuals without contact with the hospital environment (community). All samples were inoculated into the culture medium and Baird Parker, and colonies with phenotypic characteristics of S. aureus were tested for fermentation of mannitol and coagulation of rabbits plasma to confirm the identification. Samples confirmed as S. aureus were then subjected to the test of susceptibility to oxacillin and vancomycin. Samples from community and patients were also subjected to PCR confirmation of the biochemical results through DNA fragment amplification using specific primers for genes that encodes protein A, coagulase and the thermal-stable nuclease, all specific to S. aureus, and mecA, which is present in MRSA. The rate of S. aureus carriers found in the community was 17.64%, and the total of groups related to the hospital was 56.02%, of which: Students 69.64%; Technicians 51.02% and Medical Staff 47.54%. The difference in carriers of each group and in the community group was significant (P ≤ 0001), which indicates that individuals without contact with the hospital have fewer chances to be colonized by S. aureus. For MRSA, the rate of carriers in the community was 1.47%, and among individuals related to the hospital was 37.95%, while in the Students group the rate was 53.57%, in the Medical Staff group was 22.95% and in the Technicians group was 38.77%. Inside the Technicians group, 52,2% of the workers in hospitals laundry were colonized with MRSA. The difference between the groups associated with the hospital and the community group was significant (P ≤ 0001). Only two samples of patients did not confirm the prior characterization made by HUB and was considered Staphylococcus coagulase negative oxacillin resistant. All samples of community and patients identified as Staphylococcus aureus and MRSA in biochemical tests were also positive in the PCR test. The three samples of patients characterized as Staphylococcus coagulase negative oxacillin resistant was positive only for the amplification of the mecA gene, confirming the results in biochemical tests. No sample proved resistant to vancomycin. Our results suggest a high rate of MRSA carriers among hospital workers and students. The number of MRSA carriers among students and worker of the laundry raise the question about the rule of these individuals over the dissemination of MRSA through the hospital wards. Further studies focused on that matter would be necessary to answer this question. The molecular experiments showed the potential of this methodology on a fast diagnosis of MRSA infections, what would not just help the treatment, but should avoid the disseminations of those clones.

ASSUNTO(S)

infecção hospitalar staphylococcus aureus mrsa mrsa medicina hospital infections nosocomial staphylococcus aureus nosocomial

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