RESUMO
A variant of the modified carbapenem inactivation method (mCIM) was developed to detect carbapenemase activity directly from positive blood culture broths. The method, termed "Blood-mCIM," was evaluated using Bactec blood culture bottles (Becton, Dickinson and Company, Franklin Lakes, NJ) inoculated with 27 different carbapenemase-producing Enterobacteriaceae (CPE) isolates and 34 different non-CPE isolates. The assay was positive for all blood culture broths inoculated with CPE isolates and negative for all blood culture broths inoculated with non-CPE isolates, corresponding to a diagnostic sensitivity and specificity of 100%, respectively. This assay is inexpensive using "off the shelf" reagents, does not require centrifugation or mechanical lysis, and can be readily implemented in any clinical microbiology laboratory. The Blood-mCIM should facilitate expedient administration of antimicrobial therapy targeted toward CPE bloodstream infections and assist infection control and public health surveillance.
Assuntos
Proteínas de Bactérias/genética , Hemocultura/métodos , Enterobacteriáceas Resistentes a Carbapenêmicos/enzimologia , Enterobacteriáceas Resistentes a Carbapenêmicos/isolamento & purificação , Carbapenêmicos/metabolismo , Fenótipo , beta-Lactamases/genética , Antibacterianos/metabolismo , Antibacterianos/farmacologia , Enterobacteriáceas Resistentes a Carbapenêmicos/efeitos dos fármacos , Carbapenêmicos/farmacologia , Infecções por Enterobacteriaceae/diagnóstico , Infecções por Enterobacteriaceae/microbiologia , Humanos , Inativação Metabólica , Testes de Sensibilidade Microbiana , Reprodutibilidade dos Testes , Sensibilidade e EspecificidadeRESUMO
The increase in the prevalence and impact of infections caused by carbapenemase-producing Enterobacteriaceae is a global health concern. Therefore, rapid and accurate methods to detect these organisms in any clinical microbiology laboratory, including those in resource-limited settings, are essential to prevent and contain their spread. It is also important to differentiate between serine- and metal-dependent carbapenemases elaborated by carbapenemase-producing isolates for epidemiologic, infection control and prevention, and therapeutic purposes. Here, we describe the development and evaluation of the EDTA-modified carbapenem inactivation method (eCIM), an assay for discriminating between serine- and metal-dependent (i.e., metallo-ß-lactamases [MBLs]) carbapenemases when used in conjunction with the modified carbapenem inactivation method (mCIM). The eCIM had an overall sensitivity and specificity of 100% and was adopted by the Clinical and Laboratory Standards Institute as a method to use in combination with the mCIM to identify MBL-producing Enterobacteriaceae.