[Risk factors and prognosis of nosocomial pneumonia due to gram-negative bacteria in a general hospital].

Nosocomial pneumonia due to Gram-negative bacteria is one of the most important infections because of its high frequency, morbidity and mortality. The objective of this study was to determine the risk factors and prognosis for nosocomial pneumonia caused by Gram-negative bacteria. A group of 50 patients with nosocomial pneumonia due to Gram-negative bacteria were studied in a prospective, consecutive manner and compared with another group of 50 patients with similar characteristics but without infection. The diagnostic criteria, acquisition, previous infections, prognosis of the underlying disease, the initial severity of the clinical situation, presence of complications, type and evolution of antibiotic treatment were adjusted according to the criteria in the literature. Univariate and multivariate statistical analysis of the results was carried out. The risk factors found included the following: male sex, high-risk hospital units, nosocomial acquisition and previous manipulation with intubation and mechanical ventilation, previous pulmonary infections, and the use of wide-spectrum antibiotics in the six weeks prior to the study. The most isolated Gram-negative bacterium was Pseudomonas aeruginosa (32%), followed by polymicrobial flora (18%). Bacteriemia was found in 30% of the cases. Mortality was 24%, with the factors significantly associated with a poor prognosis being a serious underlying disease, a clinically critical situation, previous surgery, complications, Gram-negative bacteria, use of wide-spectrum antibiotics in the six months before the study, and advanced age. The mortality of the group was 8%. It was concluded that knowledge of the risk factors and prognosis of nosocomial pneumonia due to Gram-negative bacteria is of high importance to improve treatment and decrease morbidity and mortality.