Oğuz Vildan Avkan, Yapar Nur, Sezak Nurbanu, Cavuş Sema Alp, Kurutepe Semra, Peksel Hasan, Cakir Nedim, Yüce Ayşe
Dokuz Eylül Universitesi Tip Fakültesi, Enfeksiyon Hastaliklari ve Klinik Mikrobiyoloji Anabilim Dali, Izmir.
Mikrobiyol Bul. 2009 Jan;43(1):37-44.
Staphylococci are one of the most common pathogens isolated from nosocomial and community acquired infections. Antibiotics used by oral route such as erythromycin, clindamycin, trimethoprim-sulphamethoxazole (TMP-SMX) and quinolones are of value especially in the treatment of community acquired infections and resistance to those antibiotics may lead to therapeutic failure. Therefore in this study, susceptibility of staphylococci to TMP-SMX, rifampin, tetracycline, gentamicin, ciprofloxacin and vancomycin and the presence of inducible clindamycin resistance were investigated in two distinct university hospitals in Turkey. A total of 286 staphylococcus strains [184 Staphylococcus aureus, 102 coagulase negative staphylococci (CoNS)] were studied. Of the 90 hospital-acquired S. aureus, 44.6% were methicillin-resistant while all of the community acquired strains were methicillin-susceptible. All of the CoNS strains were isolated from nosocomial infections and 71.6% of them were resistant to methicillin. Inducible clindamycin resistance rate of CoNS strains (34.3%) was higher than that of S. aureus strains (7.1%) and the difference was statistically significant (p= 0.00001). Positive D-test among CoNS were significantly higher in S. hominis strains (p= 0.00001). Susceptibilities of S. aureus strains to tetracycline, rifampin, ciprofloxacin, gentamicin and TMP-SMX were 56%, 59%, 56%, 56% and 99%, respectively. Susceptibilities of CoNS strains to tetracycline, rifampin, ciprofloxacin, gentamicin and TMP-SMX were 73%, 72%, 39%, 40% and 46%, respectively. None of these strains were vancomycin resistant. Differences between tetracycline, rifampin, ciprofloxacin and gentamicin resistance rates among D-test positive and negative S. aureus strains were found statistically significant. Although among CoNS isolates, no statistically significant difference was found between the resistance rates, D-test positive strains were determined to be more resistant. Differences between tetracycline, rifampin, ciprofloxacin and gentamicin resistance rates among D-test positive S. aureus and CoNS strains were found statistically significant. It can be concluded that inducible clindamycin resistance should be tested for staphylococci during routine antibiotic susceptibility testing. According to the presented data, clindamycin still can be used empirically in methicillin-susceptible S. aureus infections in our region, however, the routine use of rapid, easy, reproducible and economic D-test for the determination of inducible clindamycin resistance in erythromycin resistant strains should be considered in clinical microbiology laboratories. Inducible clindamycin resistance must be anticipated carefully while considering therapeutic options especially for CoNS infections.
葡萄球菌是从医院获得性感染和社区获得性感染中分离出的最常见病原体之一。口服抗生素如红霉素、克林霉素、甲氧苄啶 - 磺胺甲恶唑（TMP - SMX）和喹诺酮类药物在治疗社区获得性感染中具有重要价值，对这些抗生素的耐药性可能导致治疗失败。因此，在本研究中，对土耳其两家不同的大学医院中的葡萄球菌对TMP - SMX、利福平、四环素、庆大霉素、环丙沙星和万古霉素的敏感性以及诱导型克林霉素耐药性的存在情况进行了调查。共研究了286株葡萄球菌菌株[184株金黄色葡萄球菌，102株凝固酶阴性葡萄球菌（CoNS）]。在90株医院获得性金黄色葡萄球菌中，44.6%为耐甲氧西林菌株，而所有社区获得性菌株均对甲氧西林敏感。所有CoNS菌株均从医院感染中分离得到，其中71.6%对甲氧西林耐药。CoNS菌株的诱导型克林霉素耐药率（34.3%）高于金黄色葡萄球菌菌株（7.1%），差异具有统计学意义（p = 0.00001）。在CoNS中，人葡萄球菌菌株的D试验阳性率显著更高（p = 0.00001）。金黄色葡萄球菌菌株对四环素、利福平、环丙沙星、庆大霉素和TMP - SMX的敏感性分别为56%、59%、56%、56%和99%。CoNS菌株对四环素、利福平、环丙沙星、庆大霉素和TMP - SMX的敏感性分别为73%、72%、39%、40%和46%。这些菌株均无万古霉素耐药。D试验阳性和阴性的金黄色葡萄球菌菌株在四环素、利福平、环丙沙星和庆大霉素耐药率之间的差异具有统计学意义。虽然在CoNS分离株中，耐药率之间未发现统计学显著差异，但D试验阳性菌株被确定为耐药性更强。D试验阳性的金黄色葡萄球菌和CoNS菌株在四环素、利福平、环丙沙星和庆大霉素耐药率之间的差异具有统计学意义。可以得出结论，在常规抗生素敏感性试验中应对葡萄球菌进行诱导型克林霉素耐药性检测。根据所提供的数据，在我们地区，克林霉素仍可凭经验用于甲氧西林敏感的金黄色葡萄球菌感染，然而，临床微生物实验室应考虑对红霉素耐药菌株常规使用快速、简便、可重复且经济的D试验来确定诱导型克林霉素耐药性。在考虑治疗方案时，尤其是对于CoNS感染，必须谨慎预期诱导型克林霉素耐药性。
