Clinical Characteristics Of Stenotrophomonas Maltophilia In Mechanical Ventilation Patients' Respiratory Tract And The First Step Study Of Its Reaction To Anti-infection Therapy

Objective To investigate the characteristic of isolation time of Stenotrophomonas maltophilia(SM) from patients'respiratory tracts and evaluate its influences on the pulmonary and systemic inflammatory reaction.Methods A retrospective analysis was performed for patients admitted to the intensive care unit (ICU) of the second affiliated hospital of suzhou university from March 2003 to January 2008 from whose respiratory tracts SM was isolated. The isolation time of SM from patients'respiratory tracts was analyzed. Patients were grouped into non-treated and treated according to whether anti-Stenotrophomonas maltophilia therapy or not. The white blood cell(WBC)counts, C reactive protein(CRP) levels in blood, oxygenation index(PO2/FiO2)and clinical pulmonary infection scores on days 1, 3, 7 after SM was isolated were compared between two groups. The clearance rates of SM in patients'respiratory tracts within 7 days were compared between two groups.Results There were 82 patients involved in this study, 39 patients were non-treated and 43 patients were treated. The mean isolation time of SM from mechanical ventilation patients'respiratory tracts was 13.4 days. WBC counts on days 1, 3, 7 after SM was isolated were all less than 10.0×109/L in tow groups. PO2/FiO2 was slightly lower than 240 mmHg on day 1 and higher than 240 mmHg on days 3, 7 in tow groups. CPIS were all lower than 6 on days 1, 3, 7 in tow groups. WBC counts, PaO2/FiO2, CRP levels and CPIS were compared synchronously on days 1, 3, 7 between non-treated and treated group,but there were no significant differences (P>0.05). WBC, PaO2/FiO2, CRP and CPIS were compared dynamically on days 1, 3, 7 in non-treated or treated group,but there were not significant variations(P>0.05). SM was cleared completely in 16(41.03%) patients in non-treated group and in 21(48.84%) patients in treated group within 7 days. The clearance rate of SM in treated group was higher than that in another group, but there was no significant difference(P>0.05).Conclusion The mean isolation time of SM in mechanical ventilation patients'respiratory tracts is about two weeks. SM isolated from mechanical ventilation patients'respiratory tracts is colonization rather than infection. Antibacterial agents don't have obvious effect on the clearance of SM in respiratory tracts.