STAPHYLOCOCCUS AUREUS IDENTIFICATION AND MOLECULAR EPIDEMIOLOGICAL CORRELATION AMONG STRAINS ISOLATED FROM PATIENTS AND HOSPITAL STAFFS

Clarice Queico Fujimura Leite (UNESP); Alice Yoshiko Tanaka (USP); Marcelo Miyata (UNESP); Ivone Anno (UNESP); Elza Masae Mamizuka (USP); Patricia Trindade (USP); Marisa Fernandez (UNESP); Edineia Correa (UNESP)

Introduction: Staphylococcus aureus nosocomial infection represents a serious health problem and its prevention and control are indispensable. Patients and health staff are considered important reservoirs and propagators of this bacterium; mainly the methicillin or oxacillin resistant S. aureus (MRSA). This agents are characterized by presence of multiple resistances for antimicrobial drugs commonly used in medical practice. Objective: The present work aimed to isolate and identify S. aureus from inpatient infections and healthy carriers (staff) as well as to establish epidemiological correlation among the isolated strains using Pulsed Field Gel Electrophoresis (PFGE). Material and methods: The bacterial samples were obtained of three hospitals from Bauru city. The identification was performed through biochemical tests (catalase test, coagulase test, manitol and maltose fermentation test and Voges-Proskauer test) and by PCR using specie specific primers. The PCR products was run on electrophoresis gel 2% and visualized on UV transilluminator. Genomic DNA analysis by PFGE was performed in 47 S. aureus strains of which 33 were from carriers and 14 from inpatients The susceptibility test of identified S. aureus strains was performed according Kirby et al. 1966. Results and discussion: All 96 samples were identified as S. aureus through metabolic tests (correlation of 100% with ATCC 29213 reference strain) and by PCR (presence of 123 bp amplification product). By susceptibility test it was verified that 5 (5.2%) staffs carried MRSA strains and 41 (87.2%) S. aureus isolates from patients were also MRSA strains.  Inpatients strains were resistant to most of the antimicrobials tested except vancomicin (100% sensible). 32 different genetic profiles were detected, where 20 strains (42,6%) had unique genetic profiles and 27 (57,4%) could be classified into 12 clusters. 8 clusters were composed only by carrier strains and 3 clusters were composed only by inpatient strains. The major cluster had 4 strains, 3 from carriers and one from inpatients. Conclusion: This study characterized S. aureus transmission among staffs and inpatients and or among staffs or among inpatients. The presence of endemic strains was also verified in the analyzed hospitals.