Retrospective study of Stenotrophomonas maltophilia bacteremia: prognostic factors and outcome of antimicrobial therapy
Date Issued
2011
Date
2011
Author(s)
Wang, Hsuan-Ying
Abstract
Background
The frequency of Stenotrophomonas maltophilia bacteremia gradually increased in recent years in the world. Besides, the increasing resistance rate of Stenotrophomonas maltophilia to many antibiotics and the considerable mortality all contribute to the need of better antibiotic treatments.
Objectives
The objectives of this study are to investigate the risk factors, mortality, prognostic factors of Stenotrophomonas maltophilia bacteremia in National Taiwan University Hospital, and to analyze the treatment outcomes with different antibiotic regimens, including comparison of the treatment outcome with monotherapy versus combination therapy. With those data, we hope we can find a way to reduce the occurrence of S.maltophilia bacteremia and find the best treatment regimens.
Study design and study population
This is a single center retrospective study performed through review of medical charts of patients diagnosed and treated at National Taiwan University Hospital (NTUH), a teaching hospital in northern Taiwan. All adult patients who developed S. maltophilia bacteremia between July 1st , 2009 and December 31st , 2010 were included. If patients had multiple episodes of S. maltophilia during the study period, only the first episode was included in this study.
Methods
Data were collected from paper or electronic medical charts, including patient profiles, underlying diseases/comorbidities, any infection and antibiotic used within 30 days prior to S. maltophilia bacteremia, and risk factors of S. maltophilia bacteremia, such as catheters, invasive procedures, surgery, immunocompromised status, prolonged hospitalization, etc. Besides, blood culture, sensitivity test, infections within 30 days after S. maltophilia bacteremia onset, clinical presentation, complication, laboratory data, antibiotic treatment, and treatment outcomes on D7, D14, D30, Day of discharge were recorded. The primary endpoint is the D14 mortality.
Statistical methods included Fisher’s exact test, χ2 test, T-test, Mann-Whitney U test. Risk factors and prognostic factors attributing to D14, D30 mortality were analyzed by univariate and multivariate logistic regression. Survival curves were drawn by Kaplan-Meier method and compared by Log-rank test.
Results
One hundred and two patients with S. maltophilia bacteremia were included in the analysis. Among these, 52 were monomicrobial bacteremia and the other 50 were polymicrobial. The mean age was 60.1 years old, and the ratio of male to female was 61:41. Most patients were nosocomial infection (87.3%), and 52.9% of bacteremia onset occurred in general wards, 35.3% in intensive care units. Source of infection was unknown in 58.8% of the patients, and 26.5% was from respiratory tracts and 14.7% was from catheters. The median Charlson’s comorbidity score was 4, and the most common underlying diseases/comorbidity was hematological diseases (80.4%), and then malignancy (71.6%), cardiovascular diseases (55.9%). In the analysis of risk factors associated with S. maltophilia bacteremia, 56.9% patients were prolonged hospitalization (>14 days), 54.9% immunocompromised, 92.2% using antibiotics within 30 days before onset, 33.3% receiving surgery, 89.2% with invasive catheters within 3 days before onset, 24.5% with ventilators, 8.8% tracheostomy, 19.6% with total parenteral nutrition. When bacteremia onset, the median Pitt bacteremia score was 2, and the median APACHE II score was 21. Complications occurred in 39.6% of the patients. The most common complication was septic shock.
S. maltophilia was almost 100% resistant to aminoglycosides, carbapenems and monobactam in the susceptibility tests. Better sensitivity appeared with co-trimoxazole, ceftazidime, ticarcillin/clavulanate, fluoroquinolones and minocycline. As to the appropriateness of empirical antibiotic and different delaying times to appropriate antibiotics, there was no significant difference for D14 and D30 mortality. Besides, there was no significantly better monotherapy or combination therapy found to be associated with lower mortality.
As to the mortality analysis, the D14 mortality rate of all 102 patients was 35%, and the D30 mortality was 47%. Independent risk factors associated with D14 mortality was septic shock (OR=34.67, 95% CI= 6.79-176.91, p<0.0001) and with D30 mortality was renal diseases (OR=13.71, 95% CI=1.31-143.44, p=0.0288).
Conclusions
In this study, the D14 and D30 mortality rate in total patients were 35% and 47%, respectively. The appropriateness of empirical antibiotics and different delaying times to appropriate antibiotics were not found to significantly affect D14 and D30 mortality. There was no better definitive antibiotic found to be associated with lower D14 and D30 mortality. The independent risk factors associated with D14 and D30 mortality were septic shock and renal diseases, respectively.
Subjects
Stenotrophomonas maltophilia
bloodstream infection
risk factor
empirical antibiotic
definitive antibiotic
combination therapy
SDGs
Type
thesis
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