metisiline dirençli stafilokoklarda glikopeptid antibiyotiklere duyarlılık ...

44
7. SUMMARY
Staphylococci are among the most important agents for hospital and
community-acquired infections. While, S. aureus was accepted as the only agent for
hospital-acquired infections in the past; nowadays, importance of CNS have begun to
increase.
In our study, a total of 240 strains (60 MRSA, 60 MSSA, 60 MRCNS and 60
MSCNS) isolated from various clinical specimens sent to our Microbiology and
Clinical Microbiology Laboratory between April 2007-April 2008, were studied. All
bacteria were inoculated on to Brain Heart Infusion agar supplemented with 4 μg/ml
and 6 μg/ml vancomycin. None of MSSA have grown on these screen agar plates.
Two of 60 MRSA, 22 of 60 MRCNS and 17 of 60 MSCNS isolates have grown on
screen agar that icluded 4 μg/ml vancomycin. On the other hand, all this bacteria
except three strains (2 MSCNS and 1 MRCNS) have grown on screen agar that
icluded 6 mμg/ml vancomycin. All bacteria’s vancomycin and teicoplanin MIC
values were determined by microdilution and E-test methods. Two S. aureus isolates
that grew on screen agar were accepted as possible VISA/h-VISA and these strains
were confirmed as h-VISA by PAP-AUC method.
The finding that most of the bacteria that grew on screen agar plates were CNS
has emphasized the importance of these bacteria as hospital-acquired infection
agents. VISA and h-VISA strains can not be detected by routine disc diffusion
methods. Methods like screen agar and PAP-AUC ratio are needed for detecting
them. Although there have been no data from controlled clinical studies which
document the increased mortality from h-VISA and VISA infections, clinicians
should bear in mind that an inadequate response to vancomycin in the treatment of
MRSA infections could be due to heteroresistance to vancomycin
The prevalances of VISA and h-VISA are not clear enough in our country.
More studies must be performed to clarify these rates and to determine the of
importance these strains.
Key Words: Staphylococcus, glycopeptide susceptibility, VISA, h-VISA.