Yeaman M R, Baca O G
Department of Biology, University of New Mexico, Albuquerque 87131.
Ann N Y Acad Sci. 1990;590:297-305. doi: 10.1111/j.1749-6632.1990.tb42236.x.
Evidence is mounting in support of the idea that different isolates of Coxiella burnetii, the etiologic agent of Q fever, are responsible for the distinct disease syndromes observed clinically. Recent studies have shown distinct antibiotic susceptibilities of different isolates of C. burnetii implicated in distinct clinical Q fever syndromes. With this in mind, we performed antibiotic susceptibility testing of the "S" isolate, a chronic-type isolate retrieved from a human patient with chronic disease. Antibiotics with differing efficacies upon the Nine Mile and Priscilla isolates were tested for their abilities to control acute and persistent "S" isolate infection of L-929 cells in vitro. The efficacies of doxycycline, rifampin, and three fluoroquinolone drugs--ciprofloxacin, ofloxacin, and norfloxacin--were tested. Compared to the chronic Q fever-implicated Priscilla isolate, which has been shown to exhibit a significant resistance to these antibiotics, the "S" isolate was much more susceptible. In persistently infected cells (greater than 300 d), the "S" isolate proved to be significantly more resistant to doxycycline, slightly more resistant to ciprofloxacin, slightly more susceptible to rifampin, and equally sensitive to ofloxacin and norfloxacin compared to the acute Q fever-implicated Nine Mile isolate. As with both the Nine Mile and Priscilla isolates, the "S" isolate was more susceptible to doxycycline, rifampin, and ofloxacin in recently infected cells (22 d) compared to cells having been persistently infected. With respect to the resistant nature of the chronic Q fever-implicated Priscilla isolate, as well as the lack of success in treating the "S" isolate in vivo, these results were unexpected. Such data supports an evolving hypothesis that the distinct C. burnetii isolates which may be responsible for the clearly different Q fever syndromes exhibit a spectrum of antibiotic susceptibility ranging from very susceptible (acute-implicate), Nine Mile isolate), to moderately susceptible (chronic-implicated "S" isolate), to moderately resistant (chronic-implicated Priscilla isolate).
越来越多的证据支持这样一种观点，即Q热的病原体伯纳特立克次体的不同分离株导致了临床上观察到的不同疾病综合征。最近的研究表明，与不同临床Q热综合征相关的伯纳特立克次体不同分离株对抗生素的敏感性不同。考虑到这一点，我们对“S”分离株进行了抗生素敏感性测试，该分离株是从一名患有慢性病的人类患者身上获取的慢性型分离株。测试了对Nine Mile和Priscilla分离株有不同疗效的抗生素在体外控制L-929细胞急性和持续性“S”分离株感染的能力。测试了强力霉素、利福平以及三种氟喹诺酮类药物——环丙沙星、氧氟沙星和诺氟沙星的疗效。与已被证明对这些抗生素具有显著抗性的与慢性Q热相关的Priscilla分离株相比，“S”分离株更易受影响。在持续感染的细胞（超过300天）中，与与急性Q热相关的Nine Mile分离株相比，“S”分离株对强力霉素的抗性明显更强，对环丙沙星的抗性略强，对利福平的敏感性略高，对氧氟沙星和诺氟沙星的敏感性相同。与Nine Mile和Priscilla分离株一样，与近期感染的细胞（22天）相比，“S”分离株在持续感染的细胞中对强力霉素、利福平及氧氟沙星更敏感。鉴于与慢性Q热相关的Priscilla分离株的抗性本质，以及在体内治疗“S”分离株缺乏成效，这些结果出乎意料。这些数据支持了一个不断发展的假设，即可能导致明显不同Q热综合征的不同伯纳特立克次体分离株表现出一系列抗生素敏感性，从非常敏感（与急性Q热相关的Nine Mile分离株）到中度敏感（与慢性Q热相关的“S”分离株），再到中度抗性（与慢性Q热相关的Priscilla分离株）。
