Kam K M, Wong P W, Cheung M M, Ho N K
Institute of Pathology, Sai Ying Pun Polyclinic, Department of Health, Hong Kong.
J Clin Microbiol. 1996 Jun;34(6):1462-4. doi: 10.1128/jcm.34.6.1462-1464.1996.
The present National Committee for Clinical Laboratory Standards (NCCLS) guideline for testing Neisseria gonorrhoeae quinolone susceptibility defines only a susceptible category for ciprofloxacin, enoxacin, lomefloxacin, and ofloxacin, while susceptible, intermediate, and resistant categories are defined for fleroxacin. To further define the criteria for detection of quinolone resistance in gonococci, by standard disk diffusion and agar dilution methodologies recommended by the NCCLS, we tested 29 strains of quinolone-resistant N. gonorrhoeae (QRNG) recently isolated from ofloxacin-treated patients who were considered clinical failures. Regression analyses were performed on these results together with those of another 20 strains showing reduced susceptibility and 13 fully susceptible strains (ofloxacin MICs of < or = 0.25 microgram/ml). With 5-micrograms ofloxacin disks, resistance in 27 (93.1%) of the QRNG strains (MICs of > 1 microgram/ml) was detected by the criterion of a zone diameter of < 22 mm, while in the remaining 2 (6.9%), the disks failed to detect resistance. A cluster of 15 highly resistant strains showed ofloxacin MICs of > 4 micrograms/ml and zone diameters of < 13 mm. When tested with 5-micrograms ciprofloxacin disks, the corresponding values for resistance and high-level resistance of these QRNG strains were < 25 mm (MICs of > 0.5 micrograms/ml) and < 15 mm (MICs of > 2 micrograms /ml), respectively. Six strains for which ofloxacin MICs were > or = 8 micrograms/ml showed no zones at all with both 5-micrograms ofloxacin and 5-micrograms ciprofloxacin disks. These QRNG strains are now firmly established in the Southeast Asia region, and it is important for clinical laboratories to recognize these clinically resistant strains and to monitor their spread.
美国国家临床实验室标准委员会（NCCLS）目前关于淋病奈瑟菌喹诺酮敏感性检测的指南仅为环丙沙星、依诺沙星、洛美沙星和氧氟沙星定义了敏感类别，而对于氟罗沙星则定义了敏感、中介和耐药类别。为了进一步明确淋病奈瑟菌喹诺酮耐药性的检测标准，我们采用NCCLS推荐的标准纸片扩散法和琼脂稀释法，对最近从被视为临床治疗失败的经氧氟沙星治疗患者中分离出的29株喹诺酮耐药淋病奈瑟菌（QRNG）进行了检测。将这些结果与另外20株敏感性降低的菌株以及13株完全敏感菌株（氧氟沙星MIC≤0.25微克/毫升）的结果进行了回归分析。使用5微克氧氟沙星纸片时，根据抑菌圈直径<22毫米的标准，在27株（93.1%）QRNG菌株中检测到耐药性（MIC>1微克/毫升），而在其余2株（6.9%）中，纸片未能检测到耐药性。一组15株高耐药菌株的氧氟沙星MIC>4微克/毫升，抑菌圈直径<13毫米。当使用5微克环丙沙星纸片检测时，这些QRNG菌株的耐药和高水平耐药的相应值分别为<25毫米（MIC>0.5微克/毫升）和<15毫米（MIC>2微克/毫升）。6株氧氟沙星MIC≥8微克/毫升的菌株在用5微克氧氟沙星纸片和5微克环丙沙星纸片检测时均未出现抑菌圈。这些QRNG菌株目前已在东南亚地区牢固存在，临床实验室识别这些临床耐药菌株并监测其传播情况非常重要。
