Diagnostic Efficacy of Carba NP Strip Test for Carbapenemase Detection

Abstract

Abstract Background Bacterial resistance to carbapenems is in the focus of attention because it envoys a time without effective antibiotics. Carbapenemase enzyme production is the main mechanism of resistance exhibited by carbapenem resistant organisms. Rapid detection of carbapenemase producing bacteria is important for initiation of treatment and infection control measures. Aim of the Work Determination of the diagnostic performance of the Carba NP strip test for the detection of carabapenemase producing gram negative bacteria. Materials and Methods The study included a total of 50 gram negative clinical isolates. All isolates were subjected to: Carba NP tube test, Carba NP strip test, and meropenem disc diffusion. All techniques were performed according to Clinical and laboratory standard institute (2018). Results Compared to the results of the meropenem (10 ug) disc diffusion method, the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of the Carba NP tube test was found to be 77.5%, 100%, 100% and 52.6 % respectively. On the other hand, the Carba NP strips test was found to have 82.5% sensitivity, 100% specificity, 100% PPV and 58.8% NPV. Conclusion The Carba NP test performed by use of the modified strip method was found to be a simple and inexpensive method that can be used for the rapid detection of carbapenemase producing gram negative bacteria with high sensitivity and specificity.