Evaluation of NitroSpeed-Carba NP Test for rapid identification among different classes of carbapenemases in Enterobacterales and Pseudomonas aeruginosa.

Abstract Objectives This study aimed to evaluate the performance of the NitroSpeed-Carba NP test for detecting carbapenemases in the clinical strains of Enterobacterales and Pseudomonas aeruginosa and analyze its advantages and limitations. Methods The antimicrobial susceptibility tests were performed according to the agar dilution method. Using the modified carbapenemase inactivation method (mCIM), polymerase chain reaction (PCR), and sequencing, the production of carbapenemase and the prevalence of genes were studied. The NitroSpeed-Carba NP tests was performed to detect different types of carbapenemases in Enterobacterales and Pseudomonas aeruginosa. The results of PCR and sequencing were used as the gold standard. Results Among 144 carbapenemase-producing and 54 carbapenemase-negative strains of Enterobacterales and Pseudomonas aeruginosa, the NitroSpeed-Carba NP test correctly detected 143/144 carbapenemase producers and 51/54 non-carbapenemase producers. Moreover, the sensitivity and specificity of all tested isolates were 99.31% and 94.44%, respectively(99.28% and 92.86% for Enterobacterales; 100% and 100% for Pseudomonas aeruginosa). The sensitivity was 100% for class A (56/56), 100% for class B (60/60), and 100% for class D (27/27). Conclusions Our results suggest that NitroSpeed-Carba NP test is a simple and valuable assay that could be used as a rapid and stable detection method to identify the carbapenemases in Enterobacterales and Pseudomonas aeruginosa strains.