Gosden P E, Andrews J M, Bowker K E, Holt H A, MacGowan A P, Reeves D S, Sunderland J, Wise R
Department of Medical Microbiology, Southmead Health Services NHS Trust, Westbury-on-Trym, Bristol, UK.
J Antimicrob Chemother. 1998 Aug;42(2):161-9. doi: 10.1093/jac/42.2.161.
The majority of clinical microbiology laboratories in the UK use comparative disc diffusion methods based on the Stokes' method to determine antibiotic susceptibility. The technical validity of the results obtained from the modified Stokes' method of disc testing and how they relate to MIC data are not known. We studied susceptibility testing using a modified Stokes' disc diffusion method for a wide range of clinical isolates against which MICs had been determined by collaborators not involved with the disc testing evaluation. Results indicated that for 1301 organism-antibiotic combinations the number of major errors (where resistant strains were reported as sensitive) was 21/468 (4.4%) and the number of minor errors (where sensitive strains were reported as resistant) was 14/713 (1.9%) using ciprofloxacin breakpoints of 0.5 and 2 mg/L. There was good correlation between the disc susceptibility test and the MIC for 119 isolates of Enterobacteriaceae tested with the exception of Serratia spp. Excluding Serratia spp. the number of major errors for Enterobacteriaceae was 1/200 (0.5%). Data revealed 2/25 (8%) major errors for Pseudomonas aeruginosa and 1/45 (2.2%) for Acinetobacter spp. Haemophilus influenzae showed a number of unexpected categorization errors. The modified Stokes' method performed accurately for Staphylococcus aureus and coagulase-negative staphylococci when tested for susceptibility to gentamicin, erythromycin, teicoplanin and vancomycin. No major errors were reported for Streptococcus pneumoniae and beta-haemolytic streptococci. Problems occurred with the detection of antibiotic resistance in Enterococcus spp. Major errors were seen for ampicillin (2/12 strains), teicoplanin (5/6 strains) and vancomycin (5/13 strains) using a 30 microg disc but only 1/13 strains using a 5 microg disc. Overall, from our data, the modified Stokes' disc diffusion antibiotic susceptibility test showed an unacceptable number of major errors but an acceptable number of minor errors.
英国大多数临床微生物实验室采用基于斯托克斯方法的比较纸片扩散法来确定抗生素敏感性。从改良的斯托克斯纸片试验方法获得的结果的技术有效性以及它们与最低抑菌浓度（MIC）数据的关系尚不清楚。我们使用改良的斯托克斯纸片扩散法对多种临床分离株进行了药敏试验，这些分离株的MIC由未参与纸片试验评估的合作者测定。结果表明，对于1301种菌株 - 抗生素组合，使用环丙沙星0.5和2 mg/L的折点，主要错误（将耐药菌株报告为敏感）的数量为21/468（4.4%），次要错误（将敏感菌株报告为耐药）的数量为14/713（1.9%）。除沙雷氏菌属外，对119株肠杆菌科细菌进行的纸片药敏试验与MIC之间具有良好的相关性。排除沙雷氏菌属后，肠杆菌科的主要错误数量为1/200（0.5%）。数据显示铜绿假单胞菌有2/25（8%）的主要错误，不动杆菌属有1/45（2.2%）的主要错误。流感嗜血杆菌显示出一些意外的分类错误。在对金黄色葡萄球菌和凝固酶阴性葡萄球菌进行庆大霉素、红霉素、替考拉宁和万古霉素药敏试验时，改良的斯托克斯方法表现准确。肺炎链球菌和β - 溶血性链球菌未报告主要错误。肠球菌属抗生素耐药性检测出现问题。使用30微克纸片时，氨苄西林（2/12株）、替考拉宁（5/6株）和万古霉素（5/13株）出现主要错误，但使用5微克纸片时仅1/13株出现主要错误。总体而言，从我们的数据来看，改良的斯托克斯纸片扩散抗生素药敏试验显示出不可接受数量的主要错误，但次要错误数量可接受。
