Dergi makalesi Açık Erişim

Bioluminescence Based Minimal Inhibitory Concentration (MIC) Determination for Biofilm Forming Bacteria

2020    Oryasin, E.

Determination of antimicrobial susceptibilities of infectious agents is important in human and veterinary medicine. The aim of this study was to test minimal inhibitory concentrations (MIC) and bactericidal effects of antibiotics using light emission properties (bioluminescence) of live bacteria. In addition, this study tested the possibility to using the measurements of light emissions to evaluate the effects of antimicrobials on the bacteria in biofilm. Light emission requires presence of the lux operon that consists of luxCDABE genes of Photorhabdus luminescens which gives light only in living cells. These genes were inserted in pAT28 plasmid and used for transformation of E. coli DH10B and biofilm forming E. coli ADU40. Light output provided a sensitive method for real-time measurements of the effects of antibiotics. The results of our study showed that using light emission properties of live bacteria the MICs of antibiotics were in agreement with the results of the conventional microdilution method. Decrease of light emission of bacteria >10 fold was considered as a bactericidal effect. Results showed that addition of chloramphenicol, meropenem, amicasin, rifampisin gentamycin ciprofloxacin, cefazolin and cefoxitin to bacterial suspensions caused >10 fold decrease of light emission at MIC levels after 18 hours of incubation, in both biofilm producer and non-producer bacteria. It was concluded that Bioluminescence can be used for the determination of both MIC and bactericidal effects by antibiotics on bacteria. These methods have an important potential for use especially to determine the effects of candidate antimicrobials in veterinary and human medicine.