Cetin Emel Sesli, Gunes Hayati, Kaya Selcuk, Aridogan Buket Cicioglu, Demirci Mustafa
Suleyman Demirel University Medical Faculty, Microbiology and Clinical Microbiology Department, Isparta, Turkey.
Int J Antimicrob Agents. 2008 Apr;31(4):364-8. doi: 10.1016/j.ijantimicag.2007.11.014. Epub 2008 Feb 21.
The prevalence of macrolide-lincosamide-streptogramin B (MLSB) resistance as well as the MLSB resistance phenotypes were investigated by the double-disk diffusion test among 532 clinical staphylococci isolates in a Turkish university hospital. The activity of other antimicrobials, including trimethoprim/sulfamethoxazole, telithromycin, quinupristin/dalfopristin, linezolid, gentamicin, chloramphenicol, ciprofloxacin and vancomycin, was also evaluated. Of 532 isolates, 38.5% were resistant to MLSB antibiotics; 63.9% of the resistant isolates exhibited a constitutive phenotype (cMLSB) whereas 36.1% expressed an inducible resistance phenotype (iMLSB). MLSB resistance was more prevalent among coagulase-negative staphylococci (CoNS) strains. Oxacillin-resistant strains exhibited significantly higher MLSB resistance rates compared with oxacillin-susceptible strains (P<0.0001). The most frequently detected resistance phenotype among the total staphylococcal isolates was the constitutive type and this phenotype was more frequently encountered among oxacillin-resistant strains. With the exception of the fully active agents such as vancomycin, linezolid and quinupristin/dalfopristin, the most effective antibiotics were telithromycin and chloramphenicol among all isolates. Susceptibility rates to other antibiotics tested were higher among isolates without MLS(B) resistance than isolates with MLSB resistance. The detection of a considerable rate (43.5%) of iMLSB resistance among erythromycin-resistant/clindamycin-susceptible strains suggests that the true percentage of clindamycin resistance may be underestimated if testing for inducible resistance is not performed.
通过双纸片扩散试验，对土耳其一家大学医院的532株临床葡萄球菌分离株进行了大环内酯-林可酰胺-链阳菌素B（MLSB）耐药率及MLSB耐药表型的调查。同时还评估了其他抗菌药物的活性，包括甲氧苄啶/磺胺甲恶唑、泰利霉素、奎奴普丁/达福普汀、利奈唑胺、庆大霉素、氯霉素、环丙沙星和万古霉素。在532株分离株中，38.5%对MLSB类抗生素耐药；63.9%的耐药分离株表现为组成型表型（cMLSB），而36.1%表现为诱导型耐药表型（iMLSB）。MLSB耐药在凝固酶阴性葡萄球菌（CoNS）菌株中更为普遍。耐氧西林菌株的MLSB耐药率显著高于对氧西林敏感的菌株（P<0.0001）。在所有葡萄球菌分离株中，最常检测到的耐药表型是组成型，且这种表型在耐氧西林菌株中更常见。除了万古霉素、利奈唑胺和奎奴普丁/达福普汀等完全有效的药物外，在所有分离株中最有效的抗生素是泰利霉素和氯霉素。在无MLS（B）耐药的分离株中，对其他所检测抗生素的敏感率高于有MLSB耐药的分离株。在红霉素耐药/克林霉素敏感菌株中检测到相当比例（43.5%）的iMLSB耐药，这表明如果不进行诱导型耐药检测，克林霉素耐药的真实百分比可能被低估。
