Clinical Features of Stenotrophomonas Maltaphilia Infection

Lee, Won Uk; Kim, Byoung Joon; Ahn, U Seouk; Won, Hyun Sang; Kim, Ki Joong; Seong, Nak Cheon; Kim, Gu Yeup; Suh, Hwan Jo

Abstract

OBJECTIVE
Stenotrophomonas maltophilia has been emerging as an important nosocomial pathogen in recent years in patients with impaired host- defense mechanism or who has been exposed to large amount of inocula. This organism is usually resistant to multiple (commonly used) antimicrobial agents, particularly to those of the beta-lactam class. To evaluate the clinical feature of Stenotrophomonas maltophilia infection and in vitro anti- microbial susceptibility, we performed a retrospective study.
METHODS
We analyzed the result of in vitro antimicrobial susceptibility test for 200 isolates of S. maltophilia and the annual isolation rate during the period between January 1990 and December 1994 in our institution, and performed a retrospective study for the available records of 165 cases among them. The data were obtained with only the first isolation of the organism for each patients.
RESULTS
Total of 165 initial isolates, the isolates were from wounds in 50(30.3%), urine in 47(28.5%), the respiratory tract in 37(22.4%), blood in 9(5.5%), bile in 6(3.6%), and miscellaneous sources in 16(9.7%). The 84.2% of isolates were hospital-acquired isolate and 58.3% of these patients had received antecedent antibiotic therapy: polymicrobial growth was demonstrated in 61.9% of the cases. In vitro antimicrobial susceptibiiity test, ofloxacin was active against the isolates in 89.2%, moxalactam in 85.9%, ciprofloxacin in 83.9%, TMP-SMX(trimethoprim-sulfamethoxazole) in 64.2%, As expected, S. maltophilia isolates were, in general, not susceptible to cephalosporins, penicillins. The annual isolation rate at Kyung Hee University hospital was not increased significantly from 1990 to 1994, 19.53 per 10,000 patients dismissals in 1990, 13.56 in 1994. The major underlying diseases of patients were malignancy(17.6%), cerebrovascular disorder(17%), diabetic mellitus(13.3%). Mortality rate is 10.3%.
CONCLUSION
S. maltophilia has been emerging as an important nosocomial pathogen in immunocompromised patients, especially those receiving broad-spectrum antimicrobial therapy. And this organism is resistant to multiple antimicrobial agents, particularly to those of the beta-lactam class. When antimicrobial treatment is necessary, the clinician should be guided by results of in vitro susceptibility testing because of the notable in vitro resistance of S. maltophilia to commonly used antibiotics. And when S. maltophilia has been recovered from a patient, wound and contact isolation is warranted.