Table_1_Antimicrobial Susceptibility and Virulence Surveillance of Campylobacter spp. Isolated From Patients in Two Tertiary Medical Centers in Taiwan.DOCX

Campylobacter spp. may cause fever, vomiting, and diarrhea in humans. Antibiotic treatment is suggested for patients with severe campylobacteriosis. However, the interpretative criteria for antibiotic susceptibility are inconsistent between Clinical and Laboratory Standards Institute and European Committee on Antimicrobial Susceptibility Testing guidelines. The aim of the study is to investigate the antibiotic susceptibility and prevalence of cytolethal distending toxin genes and to evaluate antibiotic susceptibility testing methods in the clinical laboratories of two tertiary medical centers in Taiwan. In total, 236 bacterial isolates were collected between 2001 and 2014. The disk diffusion and E-test methods were used to evaluate the antibiotic susceptibility, and broth dilution results were used as a reference. The virulence genes cdtA, cdtB, cdtC, and ceuE were detected through polymerase chain reaction. The antimicrobial sensitivity rates for erythromycin, ciprofloxacin, and tetracycline using the broth dilution assay were 80.4, 5.4, and 3.4%, respectively. No significant differences were observed in the antibiotic susceptibility of the isolates obtained from southern and northern Taiwan. However, some differences were observed between species. The susceptibility test for erythromycin (disk diffusion) showed that the isolates with small inhibition zone diameters were all resistant, and five isolates (4.0%) with large IZDs were non-sensitive. The error rate of the disk diffusion method according to the CLSI M45-A3 guideline was 5.4% (8/148). The incompatibility rates between the E-test and broth dilution methods for erythromycin, ciprofloxacin, and tetracycline were 8.0, 5.3, and 1.3%, respectively. The positive rates of the genes cdtA and cdtC were considerably higher in Campylobacter jejuni than in C. coli. Erythromycin is recommended as the first choice of treatment for campylobacteriosis. The disk diffusion method is suitable for prescreening Campylobacter susceptibility by using the CLSI M45-A2 and EUCAST criteria (low error rate of 3.4%). If antibiotic treatment fails or IZDs are between 6 and 20 mm, minimum inhibitory concentration testing by using the E-test method is highly recommended because the results of the E-test and broth dilution methods exhibit high agreement. The error rate of disk diffusion method using CLSI M45-A3 criteria is only slightly higher than B, which is also a suitable criteria.

弯曲菌属（Campylobacter spp.）可导致人类出现发热、呕吐及腹泻症状。对于重症弯曲菌病（campylobacteriosis）患者，建议采用抗生素治疗。然而，临床与实验室标准协会（Clinical and Laboratory Standards Institute, CLSI）与欧洲抗菌药物敏感性试验委员会（European Committee on Antimicrobial Susceptibility Testing, EUCAST）发布的指南中，抗生素敏感性判定标准并不统一。本研究旨在探讨抗生素敏感性与细胞致死性扩张毒素基因的流行情况，并评估台湾地区两家三级医疗中心临床实验室所使用的抗生素敏感性检测方法。本研究共收集2001年至2014年间的236株细菌分离株。采用纸片扩散法（disk diffusion）与E试验法（E-test）对抗生素敏感性进行评估，并以肉汤稀释法（broth dilution）的检测结果作为参照标准。通过聚合酶链反应（polymerase chain reaction, PCR）检测毒力基因cdtA、cdtB、cdtC及ceuE。经肉汤稀释法检测，红霉素、环丙沙星与四环素的抗菌敏感率分别为80.4%、5.4%与3.4%。台湾南部与北部分离株的抗生素敏感性无显著差异，但不同菌种间存在一定差异。针对红霉素的纸片扩散法敏感性检测结果显示，抑菌圈直径（inhibition zone diameters, IZDs）较小的分离株均为耐药株，另有5株（占比4.0%）抑菌圈直径较大的分离株表现为不敏感。依据CLSI M45-A3指南，纸片扩散法的错误率为5.4%（8/148）。E试验法与肉汤稀释法针对红霉素、环丙沙星及四环素的结果不一致率分别为8.0%、5.3%与1.3%。空肠弯曲菌（Campylobacter jejuni）中cdtA与cdtC基因的阳性率显著高于结肠弯曲菌（C. coli）。推荐将红霉素作为弯曲菌病的首选治疗药物。采用CLSI M45-A2与EUCAST指南开展纸片扩散法检测，可用于弯曲菌敏感性的初筛（错误率仅为3.4%）。若抗生素治疗无效或抑菌圈直径处于6~20 mm区间，则强烈推荐采用E试验法进行最低抑菌浓度（minimum inhibitory concentration, MIC）检测，因该方法与肉汤稀释法的检测结果一致性较高。依据CLSI M45-A3指南的纸片扩散法错误率仅略高于B类标准，同样属于适用的判定标准。