[A case-control study on the risk factors for lower respiratory tract infection by Stenotrophomonas maltophilia in a medical intensive care unit].

Objective: To explore the risk factors for lower respiratory tract infection by Stenotrophomonas maltophilia in the medical intensive care unit (MICU) in Fujian Provincial Hospital.

Methods: A 1:4 matched case-control study was carried out in the MICU in Fujian Provincial Hospital. Thirty-five patients with hospital-acquired lower respiratory tract infection by Stenotrophomonas maltophilia from 2007 to 2010 were included as cases, and 140 patients without lower respiratory tract infection served as controls. The case group included 22 cases with respiratory diseases, 4 with cerebrovascular diseases, 4 with cardiovascular diseases, 1 with hemorrhage of the digestive tract, 1 with acute pancreatitis, 1 with chronic kidney disease, 1 with cervical cancer and 1 with Alzheimer's disease. While the control group included 30 cases with respiratory diseases, 44 with cerebrovascular diseases, 14 with cardiovascular diseases, 2 with malignant tumors and 50 with others. Patients' information, general situation before being admitted to MICU, drug therapy, invasive procedures and hospital-acquired infection were analyzed. Conditional logistic regression was performed to identify independent risk factors.

Results: Univariate analysis showed that factors such as more than 4 underlying diseases (OR = 4.63), APACHE-II score ≥ 20(OR = 10.29), stay in the general ward more than 1 week before being admitted to MICU, treatment with more than 3 kinds of antibiotics (OR = 8.03), endotracheal intubation (OR = 4.10) or tracheotomy (OR = 50.29) and mechanical ventilation (OR = 7.95) were risk factors for hospital-acquired lower respiratory tract infection by Stenotrophomonas maltophilia. Multivariate logistic regression showed that variables such as APACHE-II score (OR = 8.39), kinds of antibiotics used (OR = 5.96) and tracheotomy (OR = 28.92) were independent risk factors (P < 0.01).

Conclusions: Underlying diseases, the severity of diseases, tracheotomy, mechanical ventilation, and the use of wide-spectrum antibiotics are important risk factors for lower respiratory tract infection by Stenotrophomonas maltophilia in MICU. To identify these factors and take preventive measures earlier may be useful for decreasing Stenotrophomonas maltophilia infection-related mortality.