基于NG-Test®CARBA 5的快速检测方法在碳青霉烯耐药肠杆菌目细菌血流感染中的应用

Application of Rapid Detection Method Based on NG-Test®CARBA 5 in Bloodstream Infections Associated With Carbapenem-Resistant Enterobacterales

目的比较快速检测方法(简称快速法)与传统检测方法(简称传统法)对血培养阳性瓶的病原体鉴定、药敏试验和碳青霉烯酶型检测的一致性与准确性。方法收集2022年3月–2022年5月血流感染标本中涂片报告结果为“革兰阴性杆菌”的血培养阳性标本51份。采用快速法对阳性血培养标本进行快速药敏试验(rapid antibiotic susceptibility test,RAST)和鉴定,根据RAST判读标准,利用NG-Test®CARBA 5试剂盒对亚胺培南耐药菌株进行酶型快速检测,结果采用PCR确认。同时采用传统法对血培养阳性标本纯培养后的菌落进行鉴定、VITEK 2 Compact药敏分析和酶型检测。结果细菌鉴定中,两种方法鉴定大肠埃希菌、肺炎克雷伯菌、铜绿假单胞菌和鲍曼不动杆菌的一致率均为100%。药敏试验中,两种方法的符合率较高,亚胺培南符合率为100%。碳青霉烯酶型鉴定中,传统法检测出18株产丝氨酸酶与3株产金属β-内酰胺酶的肠杆菌目细菌。快速法采用试剂盒检测出18株产KPC酶、2株产NDM酶以及1株产IMP酶的血培养标本,与PCR相比,快速法检测酶型的敏感度和特异度为100%。本实验探索的快速法对血培养阳性标本进行细菌和酶型鉴定的报告时间比传统法平均节约了1.94 d。结论本研究建立的快速法可有效缩短血培养标本报告病原微生物和药敏试验结果的时间,联合报告胶体金酶型鉴定结果可为临床医生合理使用抗菌药物、精准抗多重耐药菌感染提供参考。

Objective To compare the consistency and accuracy of a rapid test method and a traditional test method for pathogen identification,antimicrobial susceptibility and carbapenemase type identification of positive blood culture samples.Methods A total of 51 positive blood culture samples of bloodstream infection(BSI)were collected between March 2022 and May 2022.All samples were found to be“positive for Gram-negative bacilli”according to the blood smear results.The rapid method was adopted to perform rapid antimicrobial susceptibility test(RAST)and analysis of the positive blood culture samples.According to the RAST result interpretation standards,NG-Test®CARBA 5 was used for rapid carbapenemase detection of the imipenem-resistant strains and the results were confirmed by PCR.In addition,mass spectrometry,VITEK 2 Compact drug sensitivity analysis,and carbapenemase type identification were performed with the colonies cultured with positive samples according to the traditional method.Results In the identification of bacteria,the rapid method and the traditional method had 100%consistency rate in the identification results of Escherichia coli,Klebsiella pneumoniae,Pseudomonas aeruginosa,and Acinetobacter baumannii.In the antimicrobial susceptibility test,the consistency rate between the results of the two methods was high and the consistency rate for results for susceptibility to imipenem was 100%.In the identification of carbapenemase type,18 serinaseproducing strains and 3 metal-β-lactamase-producing strains of Enterobacterales were detected by the traditional method.With the rapid method,18 Klebsiella pneumoniae carbapenemase(KPC)-producing strains,2 New Delhi metallobetalactamase(NDM)-producing strains,and 1 imipenem enzyme(IMP)-producing strain were identified in the blood culture samples by using a testing kit.Compared with the PCR results,the sensitivity and specificity of the rapid test for determining carbapenemase types were 100%.In this study,we investigated a rapid method for bacteria and carbapenemase type identification of positive blood culture specimens and found that the turnaround time(TAT)of the rapid method was reduced by 1.94 days on average in comparison with the TAT of the traditional method.Conclusion The rapid method established in the study can effectively shorten the TAT for pathogenic microorganism identification and antimicrobial susceptibility test of blood culture samples,and the joint report of colloidal gold carbapenemase type identification results can provide a reference for clinicians to use antibiotics appropriately and accurately manage multi-drug resistant bacterial infections.