Relationship between antimicrobial use and the highest number of multidrug-resistant-Pseudomonas aeruginosa: a 10-year study

Introduction: Multi-drug-resistant (MDR) Pseudomonas aeruginosa is a dangerous pathogen causing nosocomial infection, particularly in low- and middle-income countries like Brazil. This retrospective study at a Brazilian university hospital examined the relationship between antimicrobial use and MDR-P. aeruginosa. Methodology: Data was collected from 358 patients with non-repetitive P. aeruginosa infections from 2009 to 2019. Antibiotic use was measured in grams and expressed as defined daily dose (DDD) per 1000 patient-days for meropenem, imipenem, polymyxin, and tigecycline. Results: Extensively drug-resistant (XDR) P. aeruginosa occurred in 36.1%, and MDR in 32.6% of cases. Risk factors for XDR infection were hospitalization prior to infection (OR = 0.9901), intensive care unit (ICU) admission (OR = 0.4766), previous antibiotic use (OR = 1.4417), and use of cefepime (OR = 0.3883). Over the ten-year period, utilization of the monitored antibiotics increased, and there was a positive correlation between the rise in MDR-P. aeruginosa and the consumption of ceftriaxone, imipenem, meropenem, and polymyxin B. The 30-day mortality rate was 40.0% for all patients and 41.0% for those infected with XDR-P. aeruginosa. Conclusions: This study highlights the negative impact of the indiscriminate use of antimicrobials, which has led to a significant increase in multidrug-resistant P. aeruginosa strains in hospitals.