evaluate the modified carbapenem inactivation method for phenotypic detection of carbapenemase production among gram-negative bacteria

Background: global growing infections by multi-drug resistance (mdr) or extensively drug-resistant (xdr) bacteria are a serious public health problem which can increase the rate of mortality and morbidity even in children. carbapenem is the last choice therapy in case of antibiotic-resistant bacteria presence. objectives: this study aimed to evaluate the easy to use method to identify carbapenemase producing bacteria which include in clsi. methods: in this descriptive study, 125 carbapenem-resistant and 97 carbapenem-susceptible gram-negative bacteria were included. pcr was used to identify carbapenemase enzymes include vim, imp, kpc, ndm-1, spm-1, oxa-48 as a gold standard method. the modified carbapenem inactivation method (mcim) was employed to phenotypically identify carbapenemase-producing bacteria. some modifications were made to the clsi proposed mcim to ensure more accurate results in contrast of pcr. results: the oxa-48 is the most prevalent detected carbapenemase and spm-1 was not detected in any of strain. the results of the mcim according to clsi guide line demonstrated 100% sensitivity to define carbapenemase-producing bacteria. however, in the cases of non-carbapenemase-producing bacteria, only 4% of mcim test results were consistent with the outcome of pcr. decrease of the incubation time and the consider 15mm as a break point could increase the accuracy of mcim against pcr. conclusions: the results of this study endorse that mcim test is a valuable method to detect carbapenemase producing bacteria if the three hours consider instead of 4 hours with 15mm break point.