Lower respiratory tract infection caused by Chryseobacterium and its susceptibility to drugs / 第二军医大学学报

ABSTRACT

Objective: To investigate the characteristics of lower respiratory tract infection caused by Chryseobacterium and its antimicrobial susceptibility in vitro . Methods: The clinical data of 52 cases of lower respiratory tract infection caused by Chryseobacterium were analyzed, and the antimicrobial susceptibility of commonly used agents was determined with the method of agar dilution. Also the 50% lethal dosage (LD 50 ) (as the marker of virulence) of 20 randomly selected Chryseobacterium strains for mice were determined. Results: (1) Thirty six was over 60 years old;all of 52 cases had underlying diseases, mainly were chronic obstruction pulmonary disease and malignant tumors. Seventeen cases had the history of incubation or tracheotomy for mechanical ventilation, and 35 had history of broad antibiotics treatment. The mean hospitalization time before infection were 35.6 d, and 38.5% of the cases had mixed infection with other bacteria. No specific clinical manifestations and chest X ray appearance revealed. (2) The in vitro activity of 25 agents showed that these strains were highly resistant. (3) The range of the LD 50 of tested strains was 4.11?10 6 5.68?10 8/mouse, suggesting low virulence of this kind of bacteria. Conclusion: The lower respiratory tract infection caused by Chryseobacterium has no unique features; the incidence of the infection increases in immunosuppressed old patients with various underlying diseases, although the virulence is relatively low. Because the clinical isolates are highly resistant, the antibiotics should be selected according to the results of bacterial sensitivity test.