• NAVIN KUMAR CHAUDHARY Department of Microbiology, Chitwan Medical College, Bharatpur, Nepal.
  • RUSAN PIYA Department of Laboratory Medicine, Chitwan Medical College, Bharatpur, Nepal.


Objectives: Staphylococcus aureus is often linked with human infection. Clindamycin is one of the key substitute antimicrobial agents in the treatment of S. aureus, especially in methicillin-resistant S. aureus (MRSA) infections. Inducible macrolide-lincosamide-streptogramin B (iMLS B) resistance is a crucial factor in antimicrobial susceptibility testing. The intention of the research was to identify S. aureus from distinct clinical specimens and investigate the prevalence of inducible clindamycin resistance among them and also study their association with MRSA.

Methods: A descriptive cross-sectional study was accomplished in the Dept. of Microbiology CMC-TH, Nepal from January 2018 to December 2020 with 525 non-repeated S. aureus obtained from a different clinical specimen. Antibiotic susceptibility test was performed by Kirby–Bauer disc diffusion method. MRSA was detected using cefoxitin (30 μg) and results were interpreted as stated by CLSI. “D-Test” was done by applying erythromycin (15 μg) and clindamycin (2 μg) as per CLSI guidelines. Data were analyzed using SPSS IBM version 20.

Results: Among 525 isolates, there were 315 (60.00%) MRSA. Results of D test analysis showed that 280 (53.33%) were MLSB sensitive while 245 (46.67%) were MLSB resistant; where 80 (15.24%) iMLSB with D zone, 100 (19.05%) constitutive MLSB (cMLSB) phenotype, and 65 (12.38%) MS phenotype. Of a total of 80 iMLSB, a significant proportion of 64 (80.00%) was MRSA (p<0.001). All the isolates were sensitive to vancomycin, teicoplanin, and linezolid. The prevalence of both iMLSB and cMLSB was high among MRSA.

Conclusion: In this study, cMLSB phenotype was predominant (19.05%) followed by iMLSB phenotype (15.25%) and then MS phenotype (12.38%). Inducible iMLS B phenotypes, as well as cMLSB, are higher among MRSA. It is advisable to include “D-Test” as a part of regular antibiotic susceptibility testing to detect iMLSB resistance among S. aureus.

Keywords: Staphylococcus aureus, Methicillin-resistant Staphylococcus aureus, Clindamycin resistance, Erythromycin resistance, D-Test, Inducible macrolide-lincosamide-streptogramin B, Constitutive MLSB, MS phenotype


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How to Cite
CHAUDHARY, N. K., and R. PIYA. “MACROLIDE-LINCOSAMIDE-STREPTOGRAMIN B RESISTANCE AMONG STAPHYLOCOCCUS AUREUS IN CHITWAN MEDICAL COLLEGE TEACHING HOSPITAL, NEPAL”. Asian Journal of Pharmaceutical and Clinical Research, Vol. 14, no. 5, May 2021, pp. 61-65, doi:10.22159/ajpcr.2021.v14i5.41012.
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