Application value of triton x-100 to modified hodge test and carbapenem inactivation method in the detection of acinetobacter baumannii carbapenemase

Abstract

Aim: To compare the sensitivity and specificity before and after the addition of Triton X-100 in the modified Hodge test (MHT) and carbapenem inactivation method (CIM) for the detection of carbapenemase in Acinetobacter baumannii. Materials and Methods: A total of 135 isolates of A. baumannii (83 carbapenem-resistant and 52 carbapenem-sensitive) were selected and the carbapenemase genotypes were detected using PCR. Carbapenemase phenotypes were tested using the MHT, Triton-MHT (THT), CIM, modified CIM (mCIM), and Triton-CIM (TCIM). Different concentrations (0.05, 0.1, 0.25, and 0.5% v/v) of Triton X-100 were used in the TCIM. Results: The sensitivity was determined to be 59.03% (MHT), 100% (THT), 6.02% (CIM), 8.43% (mCIM), 71.08% (TCIM 0.05%), 100% (TCIM 0.1%), 97.59% (TCIM 0.25%), and 96.38% (TCIM 0.5%) in 83 carbapenemase-producing isolates, and the specificity for each of these methods was 100%. Conclusion: The addition of Triton X-100 while using the MHT and CIM could significantly improve the sensitivity in the detection of A. baumannii carbapenemase with a specificity of 100%. A concentration of 0.1% v/v Triton X-100 showed the best results in TCIM.