Raviglione M C, Boyle J F, Mariuz P, Pablos-Mendez A, Cortes H, Merlo A
Cabrini Medical Center, New York, New York.
Antimicrob Agents Chemother. 1990 Nov;34(11):2050-4. doi: 10.1128/AAC.34.11.2050.
Use of ciprofloxacin as an alternative to vancomycin for treatment of methicillin-resistant Staphylococcus aureus infection has been paralleled by the emergence of resistant strains. This phenomenon has also been noticed in our hospital. To confirm our observation, methicillin and ciprofloxacin susceptibilities were tested by disk diffusion and broth microdilution techniques. We studied 83 methicillin-resistant Staphylococcus aureus isolates obtained from various sources over a 4-month period. Ciprofloxacin resistance (MIC, greater than 2 micrograms/ml) was detected in 69 isolates (83%). Prior use of ciprofloxacin was reported for 24 of 69 patients with ciprofloxacin-resistant strains and 0 of 14 patients with ciprofloxacin-susceptible strains. The day of detection during the hospital stay and the location of the source patient were not significantly different between resistant and susceptible strains. Bacteriophage typing showed a higher occurrence of nontypeable strains among ciprofloxacin-resistant strains (54%). Review of our microbiology register showed a progressive increase in the rate of resistance to ciprofloxacin during the first year of use, with initial rates being about 10% and recent rates being higher than 80%. On the other hand, methicillin-susceptible S. aureus remained uniformly susceptible to ciprofloxacin (98.4%). We conclude that prior use of ciprofloxacin is an important factor for the selection of ciprofloxacin-resistant strains and that ciprofloxacin has limited usefulness against methicillin-resistant S. aureus.
将环丙沙星作为万古霉素的替代药物用于治疗耐甲氧西林金黄色葡萄球菌感染的同时，耐药菌株也出现了。我院也注意到了这一现象。为证实我们的观察结果，采用纸片扩散法和肉汤微量稀释法检测了甲氧西林和环丙沙星的敏感性。我们研究了在4个月期间从不同来源获得的83株耐甲氧西林金黄色葡萄球菌分离株。在69株分离株（83%）中检测到环丙沙星耐药（MIC大于2微克/毫升）。69例环丙沙星耐药菌株患者中有24例曾使用过环丙沙星，而14例环丙沙星敏感菌株患者中无一例曾使用过。耐药菌株和敏感菌株在住院期间的检测日期及源患者的来源位置方面无显著差异。噬菌体分型显示，环丙沙星耐药菌株中不可分型菌株的发生率较高（54%）。查阅我们的微生物学登记资料发现，在使用的第一年中环丙沙星耐药率呈逐步上升趋势，初始耐药率约为10%，最近的耐药率高于80%。另一方面，甲氧西林敏感的金黄色葡萄球菌对环丙沙星仍普遍敏感（98.4%）。我们得出结论，先前使用环丙沙星是选择环丙沙星耐药菌株的一个重要因素，并且环丙沙星对耐甲氧西林金黄色葡萄球菌的疗效有限。
