Bacterial Resistance and Mortality in an Adult Intensive Care Unit in a Teaching Hospital in Brazil

Background: Intensive Care Units (ICU) are destinated to host severly ill patients, often in long periods of hospitalization, using invasive devices (central line catheters, mechanical ventilation and long-term urinary catheters). Patients admitted in ICU are more susceptible to develop healthcare related infections (HCRI), which frequently represent about 25% of all hospital infections. Worldwidely, bacterial resistance is of great concern by its relevance on higher length-of-stay, treatment costs, decreases in therapeutical arsenal and death relationship, which varies from 9 to 38% in ICU, and to 70% for HCRI. 

Objective: The goal was to identify related risk factors for HCRI by resistant microorganisms (RM) and for mortality in an ICU from a Teaching Hospital.

Methods: It was a prospective and descriptive epidemiological research gathering all over 24h ICU hospitalization patients admitted from 2005 to 2008, being exclued all those with incomplete/absent data. Datas were compiled in Statistical Package for Social Sciences 14 for simple frequency and logistic regression analysis, regarding odds ratio (OR), confidence interval of 95% and p<0,05 significance. 

Results: It was evaluated 2.316 patients from which 2.300 (99.3%) were included according to the inclusion criteria. Male counted 52.6%, middle age was 53y/o. Major admissions were from other hospital wards (48.5%), community (43.2%) and from Emergency Department and other hospitals (8.3%). It was verified 284 (12.3%) patients colonized by RM and 311 (13.5%) HCRI during ICU stay, from which 27% had a RM as causing agent. Yet, death was observed for 244 (10.6%) patients, being 39.3% among those with HCRI by RM. After multivaried logistic regression, It was seen statistical significance on RM HCRI development for hospital stay longer than four days (OR=6.4), community infection diagnosis (OR=0.4), long term urinary catheter use (OR=7.0) and RM colonization (OR=107.4). With respect to mortality, It was observed after the same analysis statistical significance to surgical patients (OR=0.5), severity score B (OR=4.2), C (OR=7.0), D (OR=18.6) and E (OR=76.5), besides mechanical ventilation use (OR=3.9). 

Conclusions: It might be concluded that community infection diagnosis and ICU environment and invasive devices exposure propiciate patients to RM colonizations and to later RM HCRI as well as patients clinical severity and surgical status for mortality outcomes and so is the mechanical ventilation use.