Inducible Clindamycin Resistant Staphylococcus aureus in Iran: A Systematic Review and Meta-analysis

Staphylococcus aureus is a prominent human pathogen. One of the drugs used in the treatment of staphylococcal infections (particularly infections of skin and soft tissue), is clindamycin. Resistance to clindamycin includes two types: inducible and constitutive. Routine laboratory methods of antibiotic susceptibility testing cannot detect the inducible type and Dtest is required for its detection. The purpose of this systematic review was to determine the relative prevalence of this type of resistance in Iran. Search terms "inducible clindamycin resistant", "D-test", "Staphylococcus aureus" and "Iran" were used to find relevant articles in PubMed, Google Scholar and two Persian search engines. Also, the abstracts of the recent national microbiology congresses were checked. All studies used D-test to find iMLSB (inducible macrolide, lincosamide and streptograminB resistance) phenotype among clinical isolates (not nasal swabs) of S. aureus, were included. In order to perform meta-analysis, we used “comprehensive meta-analysis” software (ver. 2). In total, 9 articles and 8 abstracts related to the topic of the study were found. Random effects meta-analyses showed a pooled estimate for percentage of iMLSB phenotype among 2683 samples of S. aureus was about 10% (95% confidence interval: 0.07-0.12). Using the fixed effect model, the odds of positive iMLSB in methicillin-resistant S. aureus was about 5 times more likely to occur in comparison with methicillin-susceptible S. aureus (95% CI: 3.49 to 7.76). Fortunately, the relative frequency of inducible resistance to clindamycin in our country is relatively low. However, we believe that D-test should be performed for all erythromicin-resistant isolates in order to identify inducible resistance to clindamycin. Moreover, reevaluation of inducible resistance to clindamycin in forthcoming years is highly recommended.