Is Ceftriaxone Sulbactum Edta (CSE) An Effective Alternative in Treatment of Carbapenem Resistant Acinetobactor (CRAB) as a Polymyxin Sparer?

INTRODUCTION: In the Indian setting, antimicrobial resistance in Acinetobacter baumannii is a considerable problem, especially in the ICUs. The annual report of the Antimicrobial Resistance Research and Surveillance Network (AMRSN) for the year 2021 stated that carbapenem resistance in Acinetobacter baumannii was 87.5%.(1) The choice of combination therapy in treating patients with CRAB infections is challenging. Polymyxin group is associated with challenges like narrow therapeutic window, highly variable and inadequate serum levels leading to sub optimum bactericidal activity and high mortality.(2) We analysed the clinical and microbiological response of different antimicrobial regimens. We accessed CSE based regimen in treatment of CRAB. We analysed efficacy and safety of polymyxin sparer regimens.(3) OBJECTIVES: 1. To establish efficacy of CSE based regimens for the treatment of CRAB related infections. 2. To access treatment response of polymyxin sparer antibiotic combinations. MATERIAL AND METHODS: This was a retrospective analysis of patients having infections due to CRAB from January 2024 to December,2024 in a tertiary care hospital. We have included the patients who survived at least for 72 hours post initiation of appropriate treatment for CRAB. We evaluated treatment response in the form of clinical improvement and/or microbiological clearance. RESULTS: We had 67 patients with culture report isolating CRAB in the study period. Out of 67 patients 46 patients had CRAB as a responsible pathogen while the remaining were colonisers. 14 patients had blood stream infection, 31 patients had ventilator associated pneumonia (VAP), 1 post operative patient had intra abdominal infection. 30 patients received polymyxin based combination which includes 12 patients on meropenem+polymyxin, 8 patients had minocycline+polymyxin, 9 had CSE +polymyxin, 1 was on polymyxin mono therapy. 16 patients were in polymyxin sparer group which included 14 patients on CSE+ minocycline combination and 2 patients were on minocycline+ sulbactum combination. Out of 30 patients, 8 patients died, from 16 patients in polymyxin sparer regimen, 2 died. In Both the groups remaining patients received therapy for 10–14 days according to clinical response. Microbiological clearance was documented by follow up cultures for 24 patients, 16 for polymyxin based regimen and 8 from the sparer regimen showed clearance. CONCLUSION: As the treatment of CRAB related infection is challenging, CSE in combination with other antimicrobial is effective choice. CSE in combination with the optimum dose of minocycline is non inferior to polymyxin based regimens. Further larger size RCT is required to replace polymyxin group in the treatment of CRAB related infections for the routine practise.