Pathogens isolated from elderly schizophrenia patients with nosocomial pulmonary infection, changes of serum D-D, PCT, SACE and their significance

OBJECTIVE To explore the distribution of pathogens isolated from elderly schizophrenia patients with nosocomial pulmonary infection, observe the changes of serum D-2 dimer (D-D), procalcitonin (PCT) and serum angiotensin converting enzyme (SACE), and analyze their significance. METHODS A total of 223 elderly patients with schizophrenia who were treated in Tianjin Anding Hospital from Mar 2019 to Dec 2020 were enrolled in the study and were divided into the infection group with 37 cases and the no infection group with 186 cases according to the status of nosocomial pulmonary infection. The baseline data were collected from the two groups of patients, the risk factors for the pulmonary infection were analyzed, the sputum specimens were collected from the patients of the infection group so as to carry out the culture of pathogens, the isolated pathogens were identified, the fasting peripheral blood specimens were collected from the two groups of patients in the morning, and the levels of serum D-D, PCT and SACE were detected. RESULTS Complication with internal medicine diseases, oral care and expectoration care were the major factors leading to the increase of risk of the infection(P<0.05). Totally 46 strains of pathogens were isolated from the 37 elderly schizophrenia patients complicated with nosocomial pulmonary infection, 13 (28.26%) of which were gram-positive bacteria, 31 (67.39%) were gram-negative bacteria, and 2 (4.35%) were fungi. The levels of serum D-D, PCT and SACE of the infection group were significantly higher than those of the no infection group(P<0.05). The areas under curves (AUCs) of the serum D-D more than 0.73 μg/L, PCT more than 1.02 ng/ml, SACE more than 40.95 U/ml and the joint detection of the three indexes were respectively 0.838, 0.789, 0.850 and 0.900 in prediction of nosocomial pulmonary infection in the elderly patients with schizophrenia, and the joint detection of the three indexes had the highest prediction efficiency(P<0.05). CONCLUSION The elderly patients with schizophrenia are vulnerable to be infected with gram-negative bacteria, which may cause the pulmonary infection, the patients with the infection show remarkable rise of serum D-D, PCT and SACE in early stage. The joint detection of the three serologic indexes can predict the nosocomial pulmonary infection in the elderly patients with schizophrenia.