Quaid I Azam University, Pakistan
Rabaab Zahra has completed her Ph.D from University of Edinburgh, UK and postdoctoral studies from University of Washington, Seattle and University of California, San Diego. She is Assistant Professor at Department of Microbiology, Quaid-i-Azam University.
The emergence of antibiotic resistant Staphylococci is an increasing problem and among available options, clindamycin is an appropriate choice for treating different Staphylococcal infections. The routine antibiotic susceptibility test is not suitable to detect inducible clindamycin resistance. The objective of this study was to investigate the prevalence of clindamycin inducible resistance among clinical isolates of Staphylococci. The clinical isolates included in this study were collected from Pakistan Institute of Medical Sciences (PIMS), Islamabad. Bacterial identification was done by colony morphology and biochemical tests. Kirby-Bauer disc-diffusion method was used to assess the susceptibility pattern of Staphylococci against different antibiotics. The results were interpreted following Clinical and Laboratory Standards Institute (CLSI) guidelines. Double Disk Diffusion test (D-test) was carried out to evaluate the clindamycin inducible resistance. A total of 176 clinical isolates of Staphylococci were collected from different sample source which were blood, pus, urine, sputum, tracheal secretions and tissue fluids. Prevalence of clindamycin inducible resistance among Staphylococci was found to be 7.23%, whereas in Staphylococcus aureus it was 5.12%, and for coagulase negative Staphylococci it was observed to be 9.45%. Resistance rate to other antibiotics were as following: cefoxitin 82.38%, linezolid 62.5%, vancomycin 13.06%, tigecycline 35.79%, tetracycline 58.52%, ciprofloxacin 54.54%, rifampin 35.22%, fosfomycin 92.61%, fusidic acid 84.09%, clindamycin 44.31%, erythromycin 53.97%, gentamicin 54.54%, chloramphenicol 18.74% and for sulfamethoxazole it was 53.40%. Inducible resistance is contributing towards clindamycin failure because clinicians prescribe clindamycin for different Staphylococcal infections without the knowledge of clindamycin inducible resistance. It is suggested that D-test should be included in routine diagnostic tests to avoid clindamycin failure.