The Relationship Between Positive Cultures With Multidrug-Resistant Microorganisms and Mortality in a General Intensive Care Unit

The patients in the intensive care unit (ICU) are more susceptible to healthcare-associated infections (HAI). Higher rates of nosocomial infections in ICU patients are associated with higher morbidity, mortality, and costs. The primary outcome of our study was to investigate the relationship between antibiotic resistance and mortality in ICU patients, and the secondary outcome was to evaluate the relationship between antibiotic resistance and the length of ICU or hospital stay.

A 5-year observational retrospective study was conducted on patients in the ICU of Hasheminejad Kidney Center affiliated with Iran University of Medical Sciences, Tehran, Iran from January 1, 2015, to January 1, 2020. The data related to age, gender, admission type, comorbidities, length of ICU stay, length of hospital stay, infection source, microorganism type, and resistance pattern of all isolates and outcomes were collected based on the study purpose.

During the 5-year study, 2899 patients were admitted to the ICU, but only 747 patients were enrolled in the study, including 426 males (57%). The median age was 65 years (19-97 years). The mean length of ICU stay was greater in culture-positive patients (8.42 vs. 3.5 days, P>0.001). Culture-positive patients had significantly higher mortality compared to culture-negative patients (63.8% vs. 36.2%, P>0.001). In our study, it was found that resistant microorganisms have increased mortality by 2.6 times in the ICU in the crude model (OR: 2.6, P>0.001).

The findings of our study suggest that multidrug-resistant pathogens increase ICU stay and mortality.