In-house rapid colorimetric method for detection of ceftazidime/avibactam resistance in carbapenem resistant Enterobacterales.

A rapid colorimetric method, the Andrade screening antimicrobial test, was compared with the E-test method to detect ceftazidime/avibactam (CZA) resistance in carbapenem resistant Enterobacterales clinical isolates. A 106 non-duplicated isolates (86 susceptible and 20 resistant to CZA) were chosen for validation. The sensitivity and specificity were 100%. This method investigates CZA resistance regardless of the resistance mechanism involved. It represents an economical and easy technique that can be applied to routine microbiology laboratories. It allows the detection of CZA resistance at 3 hours of incubation and consequently, the early implementation of accurate therapeutic interventions.