The Rate of Inducible MLSB Resistance in the Methicillin-Resistant Staphylococci Isolated From Clinical Samples.
BACKGROUND
Staphylococci are one of the most common pathogens in nasocomial and community-acquired infections. Methicillin-resistant staphylococci are known to be resistant against all beta-lactam antibiotics. Therefore, non-beta-lactam antibiotics such as macrolide and lincosamides can be used. Resistance to those antibiotics may lead to therapeutic failure. The purpose of the present study was to determine the prevalence of macrolide-lincosamide-streptogramin B (MLSB ) resistance by using D-test in staphylococcal isolates from various clinical samples.


METHODS
Seventy-one methicillin-resistant Staphylococcus isolates (six S. aureus, 65 coagulase negative staphylococci) were included in this study. Staphylococci were identified with conventional methods. According to Clinical Laboratory Standards Institute (CLSI) criteria, susceptibility testing was performed by Kirby-Bauer disk diffusion method.


RESULTS
One of six (16.6%) methicillin-resistant S. aureus isolates and 19 of 65 (29.2%) methicillin-resistant coagulase-negative staphylococci (MR-CNS) were detected as D-test positive. Twenty of 71 (28.1%) staphylococcal isolates detected as D-test positive. Inducible clindamycin resistance was found at a higher rate in MR-CNS.


CONCLUSIONS
Since the resistant community and hospital acquired staphylococcal infections have become a therapeutic problem, it is very important to detect MLSB resistance routinely in microbiology laboratories. D-test is a cheap and reliable diagnostic method that can be performed in every laboratory.
Department of Medical Microbiology, Faculty of Medicine, Mevlana University, Konya, Turkey. tozer73@hotmail.com.
Türkan
T
Toka Özer
D000900:Anti-Bacterial Agents / Q000009:adverse effects; D002490:Central Nervous System / Q000382:microbiology / Q000473:pathology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D018942:Macrolides / Q000009:adverse effects; D008297:Male; D008826:Microbial Sensitivity Tests; D013203:Staphylococcal Infections / Q000175:diagnosis* / Q000473:pathology*; D013210:Staphylococcus / Q000145:classification / Q000187:drug effects / Q000302:isolation & purification*
D000900:Anti-Bacterial Agents; D018942:Macrolides
D-test; MLSB; MLSB resistance; Staphylococcus