Polymyxin B Monotherapy vs Combination Therapy in Critically Ill Patients With Multi-drug Resistant Pathogens

The purpose of this study is to assess the safety and efficacy of polymyxin B as monotherapy versus a combined polymyxin B-carbapenem therapy against multidrug-resistant (MDR) gram negative infections. The investigators intend to evaluate if this synergistic drug regimen correlates with improved outcomes against gram-negative infections in critically ill patients including: better clinical resolution, reduced length of stay at hospital, reduced length of stay at the intensive care unit, and less recurrence of infection.