Study the efficiency of in -vitro combination between sulbactam, colistin and meropenem on extremely drug-resistant acinetobacter baumannii strain isolated from Nguyen Tri Phuong hospital

Abstract

Multidrug-resistant (MDR) Acinetobacter baumannii (A. baumannii) bacterium, a nosocomial pathogen is a global emergence of multidrug resistant strains leading to a wide variety of nosocomial infections in humans. A.baumannii are reported that no longer susceptible either to broad-spectrum cephalosporins, aminoglycosides, fluoroquinolones or even carbapenem – the antibiotics group that exhibit good activity against this bacteria. In this study, antibiotic susceptibility of Acinetobacter baumannii showed a high level of resistance with Meropenem alone (susceptibility rate was only 0.6% MIC at concentration of 2 µg/mL). However, the MDR A. baumannii is still susceptible to Colistin alone with more than 94% MIC at ≤ 2 µg/mL. Sulbactam recently is receiving renewed interest in treating Acinetobacter strains by combined this agent with a beta-lactamase susceptible antibiotic. Therefore these 3 antibiotics were considered as combination of Meropenem+Colistin and Meropenem+Sulbactam to demonstrate the synergistic antibacterial effects, the antibacterial activitites of Meropenem and Sulbactam and prevent toxicity concerns of Colistin of each combination, as a better treatment for this multidrug resistant strains. Thus, the susceptible antibiotics were used in the Checkerboard Dilution assay which the ΣFIC results showed a very high synergistic efficacy 91% in combination Meropenem+Sulbactam and 91.43% in Meropenem+Colistin. This synergistic effect has made 97.48% of Meropenem resistant isolates became sensible to Meropenem in Meropenem+Sulbactam combination, and 99.37% in Meropenem+Colistin combination. To recapitulate briefly, the combination between Sulbactam, Colistin and Meropenem has ability to against the extremely drugresistant Acinetobacter baumannii strains.