Effect of Phage-antibiotic combination therapy against clinical multidrug-resistant Acinetobacter baumannii isolates

BACKGROUND AND ABJECTIVEAcinetobacter baumannii is a major cause of nosocomial infections globally, and the increasing prevalence of multidrug-resistant strains of this bacterium has become a significant public health concern. To combat the rise in drug resistance, alternative approaches such as phage therapy have garnered considerable attention.MATERIALS AND METHODSPhage isolation and enrichment were performed using hospital wastewater samples collected from the same hospital. Phages specific to A. baumannii were isolated and purified using filtration methods and a double-agar overlay technique. Various experiments such as the efficiency of plating determination, the optimal multiplicity of infection (MOI), morphology analysis by transmission electron microscopy (TEM), one-step growth curve analysis, minimum inhibitory concentration (MIC) determination, and time-kill curve analysis for assessing combination therapy with antibiotics were conducted to further characterize bacteriophage vB_AbM_SA۱.RESULTS AND DISCUSSIONBacteriophages belonging to the myoviridae family have been isolated in this study. It has a short latent period of only ۱۰ minutes and a burst size of ۲۰ PFU/ml. Phage-antibiotic synergy (PAS) is discussed as a promising approach against multidrug-resistant bacteria. The study observed a decrease in minimum inhibitory concentration (MIC) when combining bacteriophage with meropenem, ampicillin-sulbactam, or colistin antibiotics.Time-kill tests demonstrated varying synergistic effects between phage and different antibiotic concentrations against specific isolates of A.baumannii.CONCLUSIONIn conclusion, the emergence of antibiotic-resistant strains of A. baumannii has led to the exploration of alternative therapies, such as phage therapy. The combination of meropenem,ampicillin-sulbactam, and colistin and phage therapy has been found to be more effective in reducing the bacterial load of A. baumannii in vitro than either treatment alone. The use of combination therapy may have significant implications in the treatment of A. baumannii infections and warrants further investigation.

کلیدواژه ها:

Acinetobacter baumannii ، Bacteriophage ، Drug Resistance ، Time-kill ، colistin ، ampicillin-sulbactam ، meropenem ، synergy ، synergistic effect