In Vitro Antimicrobial Combinations for Pan-Drug Resistant Acinetobacter Species

Abstract

cinetobacter spp. have emerged as one of the most important pathogens involved in health care associated infections in recent decades, characterized by their ability to accumulate different mechanisms of antimicrobial resistance, often showing a multidrug-resistant phenotype. Due to the high morbidity and mortality rates of severe drug resistant Acinetobacter spp infections, combination therapies, as opposed to monotherapy, are suggested. A synergistic effect may be developed when antibiotics are used in combination. Through this synergistic effect, treatment efficacy can be improved and resistance can be prevented. During this study, one hundred isolate of drug resistant Acinetobacter species identified by routine culture and sensitivity using disc diffusion susceptibility test were collected from critically ill patients admitted to Ain Shams University Internal medicine intensive care units. The isolates were subjected to: (i) Determination of MIC using Vitek 2 automated system to confirm resistance of Acinetobacter species to all commercially available antibiotics, (ii) Broth micro-dilution method (BMD) for determination of Tigecycline susceptibility, and (iii) Determination of antimicrobial synergy by broth micodilution (Checkerboard method).