Genotypic characterization and assessment of in- vitro synergistic antimicrobial combinations for Extremely Drug Resistant (XDR) and Pan Drug Resistant (PDR) Gram negative bacilli circulating in Oman

With antimicrobial resistance at its zenith, treating bacterial infections is becoming increasingly more challenging. New antibiotics to counter such resistance are not available. Synergistic combinations of existing antimicrobials appear to be the only solution especially in the very sick patients. Synergy results can vary depending on the bacteria and resistance determinants expressed by them. This study will evaluate antimicrobial synergistic responses against genotypically characterized XDR and PDR Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa and Acinetobacter baumanii complex. Synergistic outcomes will also be assessed in relation to resistance determinants viz OXA-48, NDM1, KPC, IMP,VIM etc. We will perform chequerboard,time kill assay and E test with combinations of tigecycline, carbapenems, colistin, fosfomycin,amikacin, minocycline, trimethoprim-sulfamethoxazole and levofloxacin. The results of these assays will shed valuable light on which antibiotic combinations will yield synergy. Armed with this knowledge, clinicians can make informed, judicious and timely decisions as to which antibiotics to prescribe for optimum patient care. This will in turn significantly reduce patient morbidity and mortality.