https://imcjms.com/public Ibrahim Medical College Journal of Medical Science https://imcjms.com/public/registration/journal_full_text/41 Tue, 02 Aug 2016 10:09:44 +0000 Inducible clindamycin resistance was deremined in 200 clinical isolates of staphylococci from pus (53.5%) and wound  swab (46.5%). The study was done from July 2009 to June 2010, in the Department of Microbiology, BIHS Hospital Dhaka. Inducible clindamycin resistance was demonstrated by placing an erythromycin disc (15 mg) 15 mm apart from the edge of a clindamycin (2 mg) disc in Mueller Hinton agar. When the clindamycin inhibited zone becomes D- shaped the organism was regarded as postive for inducible resistance (D- test positive). Out of 200 staphylococci, 20% had inducible clindamycin resistance, 5% had constitutive clindamycin resistance and remaining 75% was clindamycin sensitive. In case of methicillin resistant Staphylococcus aureus (MRSA), 48% had inducible clindamycin resistance while 11.5% was constitutively resistant to clindamycin and remainder were clindamycin sensitive. All clindamycin resistant strains were 100% sensitive to vancomycin and linezolid followed by gentamycin (42%) and tetracycline (42.3%). The findings demonstrated that a substantial proportion of staphylococci in our tertiary care hospital had inducible   resistance to clindamycin. Address for Correspondence:Dr. S M Zahurul Haque Asna, Professor, Department of Microbiology, Bangladesh Institute of Health Sciences(BIHS), 125/1 Darussalam, Mirpur, Dhaka-1216, Bangladesh. e-mail: asnabd04@yahoo.com   Multidrug resistance is an ever increasing problem in staphylococci which is responsible for nosocomial as well as community acquired infections.1 Methicillin resistant Staphylococcus aureus (MRSA) poses special threat to treatment because these are resistant to most common drugs.2,3 So, newer drugs are needed to treat infections with MRSA. The prevalence of positive D–test has been reported as 21.9% in all staphylococcal strains, 24.4% in MRSA and 14.8% in MSSA (methicillin sensitive Staphylococcus aureus) in India.5 The rate in methicillin sensitive and resistant coagulase negative Staphylococus (CoNS) are 25.7% and 19.9%  respectively.5   The study was conducted over a period of one year from July 2009 to June 2010 at the Department of Microbiology, BIHS hospital, Mirpur, Dhaka. Clinical specimens such as pus and wound swab were cultured and Staphylococcus was identified following standard procedure.7,8 The erythromycin-clindamycin double disc susceptibility test (D-test) was performed as per CLSI guideline 2004.6 An erythromycin disc (15 mg) was placed 15mm apart from the edge of a clindamycin (2 μg) disc in Mueller Hinton agar media. When the clindamycin zone became D- shaped, the organism was regarded as positive for inducible resistance to clindamycin (D- test positive, Fig-1).6,7 Fig-1. D-test positive isolate showing flattening of zone of inhibition of clindamycin towards to erythromycin disc Results     Table-2: Antibiotic susceptibility profile of Clindamycin resistant MRSA (n=52)   Clindamycin, though not a new drug and is used for other purposes, can be used for the treatment of MRSA and multiple resistant staphylococci. It is a lincosamide drug having good tissue penetration and is well tolerated even in kidney diseases.4 This study has been conducted to see the prevalence of inducible clindamycin resistance among clinical isolates of staphylococci and to study the antibiogram of clindamycin resistant strains.In this study, 22% (44 out of 200) staphylococci had inducible clindamycin resistance, 5% had constitutive clindamycin resistance The incidence of constitutive clindamycin resistance is variable in different studies. Angel et al. and Gadepalli et al. did not find any constitutive resistant strains in their studies.10,11 Others found constitutive clindamycin resistance in 3.8%- 44.2% of their MRSA isolates.9,12,5 However, incidence of constitutive clindamycin resistance in our study was 5% in MRSA strains which is much nearer to that of Mallick et al.9 In our study, inducible clindamycin resistance was found in 4.8% of coagulase negative staphylococci (CoNS). However, no constitutive clindamycin resistance was found in these strains.  Yilmaz et al. reported both inducible (24.3%) and constitutive (31.5%) clindamycin resistance in CoNS.5   1.   Hiramastsu K, Hankaki H, Ino T, Yabuta K, Oguri T. Tenover F.C. Methicillin-resistant Staphylococcus aureus Clinical Strain with reduced vancomycin susceptibility. J. Antimicrob Chemother 1997; 40: 135-6. 3.   Levinson W. Gram positive cocci. Medical microbiology and immunology. 9th edition. Lange Medical Books/McGrawHill Newyork 2007; 110. 5.   Yilmaz G, Aydin K, Iskender S, Caylan R and Koksal I. Detection and prevalence of inducible clindamycin resistance in staphylococci. Journal of Medical Microbiology 2007; 56: 342-345. 7.   Weisblum B and Demohn V. Erythromycin inducible resistance in Staphylococcus aureus; survey of antibiotic classes involved. J. Bacteriol 1969; 98: 447-452. 9.   Mallick SK, Basak S, Boses S. Inducible clindamycin resistance in Staphylococcus aureus – Therapeutic challenge. Journal of Clinical and Diagnostic Research 2009; 3: 1513-1518. 11.Gadepalli R, Dhawn B, Mohanti S, Kapil A, Das BK and Chaudhary R. Inducible clindamycin resistance in clinical isolates of Staphylococcus aureus. Indian J Med Res 2006; 123: 571-3. 2026 Ibrahim Medical College. All rights reserved.