Associated factors of Acinetobacter baumannii complex in hospitalized patients: A case-control study

Acinetobacter baumannii complex are microorganisms of critical priority of resistance, being associated with higher costs and negative outcomes for hospitalized patients. Thus, the study aimed to analyse the factors associated with A. baumannii complex infection in various hospital sectors.

This is a case-control study that included patients hospitalized from January 2017 to June 2019. Demographic, microbiological and clinical variables were collected from each patient. All cases had positive culture results for A. baumannii complex resistant to more than three classes of antimicrobials. Carbapenem-resistance was examined by the disk diffusion test, while the broth microdilution method was used to determine the susceptibility to colistin.

A. baumannii complex infection was mostly present in ICU (74.2%) than in other hospital areas. The bacteria was also linked with the length of hospitalization until the results for the culture (OR = 1.13; 95% CI: 1.06 - 1.21; p < 0.001) and with pneumonia associated with mechanical ventilation (OR = 4.48; 95% CI: 1.55 - 13.00; p = 0.006). Moreover, patients exposed to infection with multidrug-resistant A. baumannii complex had higher risks of death (OR = 3.25; 95% CI: 1.06 - 9.91; p = 0.039).

This study provides evidence that A. baumannii complex infection is associated with the number of days of hospitalization up to culture positivity, pneumonia associated with the use of mechanical ventilation and death. Infections appear to be more critical in ICU when compared to other areas. Taken together, these findings could support hospital infection surveillance programs, as well as prevention measures to reduce mortality rates and other complications.