Risk Factors for Antibiotic Resistance and Survival Analysis of Severe Pneumonia Patients Infected with MDR and XDR Pathogens: A Retrospective Cohort Study

Abstract Background : One of the most important challenges to global public health is antimicrobial resistance. Prominent forms of antimicrobial-resistant infections include multidrug-resistant (MDR) and extensively drug-resistant (XDR) pathogens. This study aimed to identify risk factors forantimicrobial resistance and conduct a survival analysis of patients with MDR and XDR pathogens among severe pneumonia patients. Methods : This retrospective study collected data from severe pneumonia patients admitted to the intensive care unit (ICU) from January 2016 to December 2022. Four hundred fifteen severe pneumonia patients were enrolled in our study. Respiratory specimens were collected via bronchial washing. Risk factors for antimicrobial resistance and 30-day mortality were analyzed. Bivariate analysis was performed to analyze the association of subject characteristics with antibiotic susceptibility using 2x2 table in chi-square or Fisher’s exact tests. Variables with p values <.25 were further analyzed with multivariate logistic regression. All p values <.05 were considered statistically significant. Kaplan‒Meier survival curves were generated with the log-rank test. Results : Three hundred thirty-three subjects with multidrug-resistant pathogens were analyzed. Klebsiella pneumoniae (29%), Acinetobacter baumannii ( 24 %) and Pseudomonas aeruginosa (12%) were the most frequently isolated pathogens. The majority of patients with underlying cerebrovascular disease, sepsis and ventilator-associated pneumonia (VAP) had aminoglycoside, carbapenem and quinolone resistance ( p <.05). There was no significant difference in survival between the MDR and XDR groups ( p = 0,634). Conclusions : Our study showed a high incidence rate of gram-negative pathogens isolated from severe pneumonia patients in the ICU setting. Awareness of risk factors for antimicrobial resistance may contribute to the management of severe pneumonia patients and antibiotic stewardship. Further prospective studies are needed to establish a causal relationship of antimicrobial resistance with carbapenems, quinolones and aminoglycosides. Additionally, analyzing drug resistance genes is essential to improve the identification of MDR and XDR pathogens.