Can flow cytometry be an alternative method for the detection of antimicrobial resistance?

BACKGROUND

The inappropriate use of antibiotics may cause antibiotic resistance, cause side effects, and eventually cause an increase in healthcare costs. This study aimed to determine a flow cytometry-based test to detect ESBL E. coli and MDR P. aeruginosa in a short time.

METHODS

The study included 25 E.coli isolates and 25 P.aeruginosa isolates identified by Phoenix TM 100 automated system [Becton Dickinson, USA]. In the flow cytometric method, the percentages of death cells exposed to cephalosporin including ceftazidime [CAZ] or cefotaxime [CTX] and clavulanic acid [CLA] combination, were compared with death cells exposed only to a cephalosporin [CAZ or CTX]. CLA index values [CAZ-CLA and CTX-CLA indices] were obtained for CTX and CAZ. Index values that were higher than 1.5 just for one cephalosporin were accepted as positive.

RESULTS

Cell viability was performed after 1-hour exposure to the drugs. When PI staining was applied to ESBL-treated and MDR-treated bacteria, 65% and 85% had nonviable membranes, indicating the method efficiently identified only cells with damaged membranes.

CONCLUSION

Flow cytometry is a rapid and reliable method for the detection of ESBL and MDR in clinical microbiology laboratories.