Indian Journal of Pathology and Microbiology

ORIGINAL ARTICLE
Year
: 2008  |  Volume : 51  |  Issue : 3  |  Page : 376--378

Phenotypic detection of inducible clindamycin resistance among Staphylococcus aureus isolates by using the lower limit of recommended inter-disk distance


GS Ajantha, Raghavendra D Kulkarni, Jeevan Shetty, C Shubhada, Pavithra Jain 
 Department of Microbiology, SDM College of Medical Sciences and Hospital, Sattur, Dharwad - 580 009, Karnataka, India

Correspondence Address:
G S Ajantha
Department of Microbiology, SDM College of Medical Sciences and Hospital, Dharwad - 580 009, Karnataka
India

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 and Methods: 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. Statistical Methods: 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 .


How to cite this article:
Ajantha G S, Kulkarni RD, Shetty J, Shubhada C, Jain P. 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;51:376-378


How to cite this URL:
Ajantha G S, Kulkarni RD, Shetty J, Shubhada C, Jain P. Phenotypic detection of inducible clindamycin resistance among Staphylococcus aureus isolates by using the lower limit of recommended inter-disk distance. Indian J Pathol Microbiol [serial online] 2008 [cited 2021 Nov 28 ];51:376-378
Available from: https://www.ijpmonline.org/article.asp?issn=0377-4929;year=2008;volume=51;issue=3;spage=376;epage=378;aulast=Ajantha;type=0