目标:艰难梭菌感染(C.difficile)通常在抗生素治疗其他感染后发生,并可能导致严重程度不同的胃肠道疾病。艰难梭菌可以对广谱的抗微生物剂具有抗性。抗菌素耐药性(AMR)的检测对于指导总体人群中AMR模式的最佳治疗和监测很重要。基因型标记和表型AMR之间的相关性尚未明确。这项研究的目的是评估AMR的基因型决定子是否以及在多大程度上与表型抗性相关。
方法:使用Sensittre平板或E-test对99株艰难梭菌分离株进行表型鉴定,以确定对8种抗生素的耐药性。对其基因组进行了抗性遗传标记的筛选。准确性,灵敏度,特异性,计算阳性和阴性预测值.
结果:我们发现头孢西丁和克林霉素的耐药率很高(>50%),对莫西沙星和四环素的中等耐药率(10%-50%)和对亚胺培南的低耐药率(<10%),甲硝唑,万古霉素,还有利福平.对于莫西沙星,四环素,和克林霉素,我们发现基因型和表型AMR之间有很好的相关性,总体准确率为96%(95%CI90%-100%),78%(95%CI68%-86%)和86%(95%CI77%-92%)。对于其他五种抗生素,无法对相关性进行准确估计。
结论:我们的结果表明,对于莫西沙星,四环素和克林霉素,艰难梭菌的表型抗性可以通过遗传指标预测并用于公共卫生目的。然而,其他五种抗生素,该模型不准确,需要进一步开发。
OBJECTIVE: Infection with Clostridioides difficile usually occurs after antibiotic treatment for other infections and can cause gastro-intestinal disorders of variable severity. C. difficile can be resistant to a wide spectrum of antimicrobials. Detection of antimicrobial resistance (AMR) is important to direct optimal treatment and surveillance of AMR patterns in the overall population. Correlation between genotypic markers and phenotypic AMR is not yet well defined. The aim for this study is to assess whether and to what extent genotypic determinants of AMR correlate with phenotypic resistance.
METHODS: C. difficile isolates (n = 99) were phenotypically characterized for resistance to eight antibiotics using Sensititre plates or E-tests. Their genomes were screened for genetic markers of resistance. Accuracy, sensitivity, specificity, positive and negative predictive values were calculated.
RESULTS: We found high rates of resistance (>50 %) to cefoxitin and clindamycin, intermediate rates of resistance (10 %-50 %) to moxifloxacin and tetracycline and low rates of resistance (<10 %) to imipenem, metronidazole, vancomycin, and rifampicin. For moxifloxacin, tetracycline, and clindamycin, we found a good correlation between genotypic and phenotypic AMR, with an overall accuracy of 98 % (95 % CI 93%-100 %), 78 % (95 % CI 68%-86 %) and 86 % (95 % CI 77%-92 %) respectively. For the other five antibiotics, accurate estimates on the correlation could not be made.
CONCLUSIONS: Our results suggest that for moxifloxacin, tetracycline and clindamycin, phenotypic resistance in C. difficile can be predicted by genetic indicators and used for public health purposes. However, for the other five antibiotics, the model is not accurate and further development is necessary.