Phenotypic detection of inducible clindamycin resistance among Staphylococcus aureus isolates by using the lower limit of recommended inter-disk distance.
Indian J Pathol Microbiol
;
2008 Jul-Sep; 51(3): 376-8
Article
in English
| IMSEAR
| ID: sea-74565
ABSTRACT
CONTEXT Clindamycin is one of the important alternative antibiotics in the therapy of Staphylococcus aureus, particularly in methicillin-resistant S. aureus (MRSA) infections. Inducible clindamycin resistance (iMLS B--inducible Macrolide-Lincosamide-Streptogramin B resistance) is a critical factor in antimicrobial susceptibility testing. AIMS:
To know the rate of inducible clindamycin resistance among clinical isolates of Staphylococcus aureus in our hospital by Disk approximation test (D-test) using the average recommended inter-disk distance and comparing the results with that of D-test using the lower limit of recommended inter-disk distance. MATERIALS ANDMETHODS:
A total of 51 erythromycin-resistant and clindamycin-susceptible S. aureus isolates were subjected to disk approximation testing with 21 +/- 1 mm and 15 mm edge-to-edge distance between the clindamycin and erythromycin disks. STATISTICALMETHODS:
Z-test levels.RESULTS:
Among 51 erythromycin-resistant and clindamycin-susceptible S. aureus isolates, 25 (49%) were recorded as inducible clindamycin resistant by D-test with 21 +/- 1 mm edge-to-edge distance between the clindamycin and erythromycin disks. When we re-tested all the 51 strains by D-test with 15 mm inter-disk distance, we identified 14% more iMLS B strains previously reported as D-test negative. Z-test for MRSA indicates that 15 mm edge-to-edge distance has significant advantage.CONCLUSIONS:
Since the incidence of inducible clindamycin resistance is high (63% in our study), accurate identification of inducible clindamycin resistance is important to prevent therapeutic failure in infections caused by these strains. We suggest the use of D-test with 15 mm edge-to-edge inter-disk distance for detecting iMLS B .
Full text:
Available
Index:
IMSEAR (South-East Asia)
Main subject:
Staphylococcus aureus
/
Humans
/
Clindamycin
/
Microbial Sensitivity Tests
/
Sensitivity and Specificity
/
Drug Resistance, Bacterial
/
Anti-Bacterial Agents
Type of study:
Diagnostic study
/
Evaluation studies
/
Prognostic study
Language:
English
Journal:
Indian J Pathol Microbiol
Year:
2008
Type:
Article
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