Abstract:

Objective To evaluate the performance of screening methods by home-made plate containing meropenem 1 μg/mL（drug screening method） and MacConkey agar with 10 μg meropenem（disk screening method） in the screening of carbapenem-resistant Enterobacteriaceae（CRE） colonized in intestinal tract. Methods A total of 306 stool samples for CRE screening were collected from hospitalized children between July 2019 and March 2020,and drug and disk screening methods were used to determine CRE isolates colonized in stool samples. The results of polymerase chain reaction（PCR） amplified carbapenemase genes（PCR screening method） were taken as a standard to evaluate the performance of the 2 screening methods mentioned above. Results Among the 306 stool samples,the positive rate of PCR,drug and disk screening methods were 12.1%（37/306）,17.3%（53/306）and 15.4%（47/306）,respectively. The PCR screening method was used as a standard,the sensitivity,specificity,positive predictive value,negative predictive value and consistency of drug screening method were 97.3%,93.7%,67.9%,99.6% and 94.1%,respectively,and the Kappa value was 0.77（P<0.05） with good consistency. The sensitivity,specificity,positive predictive value,negative predictive value and consistency of disk screening method were 91.9%,95.2%,72.3%,98.8% and 94.8%,and the Kappa value was 0.78（P<0.05） with good consistency. There were 6 samples as positive both by drug and disk screening methods,but the carbapenemase genes were negative by PCR screening method. Considering CRE isolates might have other drug resistance mechanisms,it should consider those samples as positive for CRE screening. Conclusions The drug and disk screening methods can be applied to screen and determine the CRE colonized in intestinal tract. Clinical laboratories can select the corresponding methods according to the specific situation.

Key words: Carbapenem-resistant Enterobacteriaceae, Intestinal colonization, Drug screening method, Disk screening method