Chen D K, McGeer A, de Azavedo J C, Low D E
Department of Medicine, University of Toronto, Canada.
N Engl J Med. 1999 Jul 22;341(4):233-9. doi: 10.1056/NEJM199907223410403.
Fluoroquinolones are now recommended for the treatment of respiratory tract infections due to Streptococcus pneumoniae, particularly when the isolates are resistant to beta-lactam antibiotics. Although pneumococci with reduced susceptibility to fluoroquinolones have been identified, their prevalence has not been determined in a defined population.
We performed susceptibility testing on 7551 isolates of S. pneumoniae obtained from surveillance in Canada in 1988 and from 1993 to 1998. Pneumococci with reduced susceptibility to fluoroquinolones (defined as a minimal inhibitory concentration of ciprofloxacin of at least 4 microg per milliliter) were further characterized. We also examined antibiotic prescriptions dispensed in Canadian retail pharmacies.
Between 1988 and 1997, fluoroquinolone prescriptions increased from 0.8 to 5.5 per 100 persons per year. The prevalence of pneumococci with reduced susceptibility to fluoroquinolones increased from 0 percent in 1993 to 1.7 percent in 1997 and 1998 (P=0.01). Among adults, the prevalence increased from 1.5 percent in 1993 and 1994 combined to 2.9 percent in 1997 and 1998 combined. The prevalence was higher in isolates from older patients (2.6 percent among those 65 years of age or older vs. 1.0 percent among those 15 to 64 years of age, P<0.001) and among those from Ontario (1.5 percent, vs. 0.4 percent among those from the rest of Canada; P< 0.001). Fluoroquinolone use was greatest among the elderly and in Ontario. The 75 isolates (17 serotypes) of pneumococci with reduced susceptibility to fluoroquinolones were submitted by 40 laboratories in eight provinces. Reduced susceptibility to fluoroquinolones was associated with resistance to penicillin.
The prevalence of pneumococci with reduced susceptibility to fluoroquinolones is increasing in Canada, probably as a result of selective pressure from the increased use of fluoroquinolones.
目前推荐使用氟喹诺酮类药物治疗肺炎链球菌引起的呼吸道感染，尤其是当分离菌株对β-内酰胺类抗生素耐药时。虽然已发现对氟喹诺酮类药物敏感性降低的肺炎球菌，但尚未在特定人群中确定其流行情况。
我们对1988年以及1993年至1998年期间从加拿大监测中获得的7551株肺炎链球菌进行了药敏试验。对氟喹诺酮类药物敏感性降低的肺炎球菌（定义为环丙沙星的最低抑菌浓度至少为每毫升4微克）进行了进一步特征分析。我们还检查了加拿大零售药店发放的抗生素处方。
1988年至1997年期间，氟喹诺酮类药物的处方量从每年每100人0.8张增加到5.5张。对氟喹诺酮类药物敏感性降低的肺炎球菌的流行率从1993年的0%增加到1997年和1998年的1.7%（P=0.01）。在成年人中，流行率从1993年和1994年合并时的1.5%增加到1997年和1998年合并时的2.9%。老年患者分离株中的流行率更高（65岁及以上患者中为2.6%，而15至64岁患者中为1.0%，P<0.001），安大略省分离株中的流行率也更高（1.5%，而加拿大其他地区分离株中为0.4%；P<0.001）。氟喹诺酮类药物的使用在老年人和安大略省最为普遍。对氟喹诺酮类药物敏感性降低的75株（17种血清型）肺炎球菌由八个省份的40个实验室提交。对氟喹诺酮类药物敏感性降低与对青霉素耐药有关。
在加拿大，对氟喹诺酮类药物敏感性降低的肺炎球菌的流行率正在上升，这可能是由于氟喹诺酮类药物使用增加带来的选择压力所致。
