Risk Factors for the Antibiotic Resistant Gram-Negative Bacilli Associated Infections in Burn Patients and the In-Vitro Susceptibility of Colistin

Background: Burns patients are predisposed to infectious complications. Amongst microbial infections, Gram-negative bacilli are the most prevalent bacteria in the burn units. Objectives: The current study aimed to identify the risk factors associated with antibiotic-resistant Gram-negative bacilli in hospitalized burn patients and determine the in-vitro susceptibility of these organisms to colistin. Methods: Two hundred burn patients hospitalized in the burn unit and ICU burn ward were allocated to two groups (each with 100 patients) of patients with antibiotic-resistant Gram-negative bacilli infections and the other with antibiotic susceptible Gram-negative bacilli associated infections. The susceptibility of Gram-negative bacilli was done towards various antibacterial agents by the Kirby-Bauer method. Susceptibility of colistin was performed using both E-test and disc diffusion methods. Results: The history of antibiotic usage, length of ICU stay, mechanical ventilation, and catheter usage were the most important risk factors for infections associated with antibiotic-resistant Gram-negative bacilli. Pseudomonas aeruginosa and Acinetobacter baumannii were the most prevalent bacteria in the burn unit. Only one A. baumannii isolate was found resistant toward colistin by both disk diffusion and E-test methods. Conclusions: Burn patients are prone to infections, and Gram-negative bacilli predominates in patients harboring risk factors. These findings influence the choice of traditional therapeutic regimens in such patients. Colistin served as an appropriate antibiotic choice.