Ceftriaxone-sulbactam-EDTA susceptibility profile of multi-drug resistant gram-negative bacterial isolates: Experience from a tertiary care teaching hospital in Rishikesh, Uttarakhand

Introduction: Studies have shown that ceftriaxone-sulbactam-EDTA combination is a promising therapeutic option as carbapenem sparer in cases of infections caused by ESBL and MBL producing pathogens, respectively. This study is aimed to generate preliminary data on in-vitro susceptibility profile of clinical multi-drug resistant (MDR) Gram-negative bacterial isolates to ceftriaxone-sulbactam-EDTA combination. Materials and Methods: A cross-sectional study was conducted from January 1st, 2019 to October 31st, 2019. Antibiotic susceptibility data (including that of ceftriaxone-sulbactam-EDTA combination) of 200 multi-drug-resistant Gram-negative bacterial isolates obtained from various nonrepetitive clinical samples of patients of all age groups and sexes, was retrospectively analyzed. All clinical samples were processed aerobically as per standard guidelines, and the bacterial isolates obtained in culture were identified by conventional biochemical methods. Antibiotic susceptibility testing of bacterial isolates was performed using the modified Kirby Bauer disk diffusion method, the results of which were interpreted as per the Clinical and Laboratory Standards Institute (CLSI) guidelines 2019. In vitro susceptibility test results of ceftriaxone-sulbactam-EDTA combination, disks were interpreted as per the manufacturer's instructions. Results: Acinetobacter spp. was the most common isolate (53%), followed by Escherichia coli (20.5%), Klebsiella spp. (17.5%), Pseudomonas aeruginosa (16.5%), Citrobacter spp. (2%), and Proteus spp. (1%), respectively. 99.1%, 92.7%, 88.6%, and 69.3% of Acinetobacter spp., E. coli, Klebsiella spp. and P. aeruginosa, respectively, were susceptible to ceftriaxone-sulbactam-EDTA combination disks. Conclusions: The preliminary data generated by our study could be an eye-opener for clinicians practicing in this part of the country and should prompt further investigation in the form of clinical trials.