Influence of Antibiotics Use on Stenotrophomonas maltophilia Colonization or Infection in Patients with Malignancies
Date Issued
2008
Date
2008
Author(s)
Chiu, Yu-Hsin
Abstract
Backgroundosocomial infections caused by Stenotrophomonas maltophilia (SMA), an emerging pathogen attributed to inherited multi-drug resistance, has increased and frequently seen in patients with hematologic malignancies. Although previous studies have reported the relationships of antibiotic uses to colonization of SMA, there are several drawbacks in previous studies. The majority of study designs are based on a cross-sectional ecological design. Very few studies applied a longitudinal time series ecological design to elucidate these associations, especially in patients with hematologic malignancies. It is also lacking of a study design at individual level to throw light on the effect of the combination of different kinds of antibiotic uses on the risk for SMA. Whether the combined use of two or three kinds of drugs in hematologic malignancy patients is synergistic is hardly addressed.atients and Methodshere are two kinds of time series study design used in our study. The first is an ecological time series design that is tailored for estimating the burden of SMA, assessing the impact of hospital-wide hand hygiene program, and studying the correlation between the consumption of antibiotic uses and incidence density of SMA at ward level by using five-year period data from 2002 to 2006. The second design is a case-based only cross-over time series design which is regarded as an atomic level. In this design, the episode of having SMA colonization or infection during a month is defined as event. A series of time epochs over five-year period was constructed for elucidating the association between antibiotic use and SMA infection at individual level. Prior therapy of antibiotic uses was defined as 14 days before culture for the ascertainment of SMA. esultshe incidence density of SMA colonization or infection in patients with malignancies was 3.9±2.1 SMA isolates per 1000 patient-days, which is higher than oncologic wards. Patients at hematologic ward were 3.27-fold (95%CI:1.96-5.44; p <0.001) risk for SMA colonization or infection compared with patients at oncologic wards, but hand hygiene promotion program to avoid exogenous transmission was lacking of significant effect on SMA colonization or infection. After excluding the effects of ward and patients, the use of 4th generation cephalosporins (HR:1.80; 95%CI:1.34-2.42), anti-Pseudomonas penicillins (HR:1.60; 95%CI:1.19-2.16), carbepenem (HR:1.45; 95%CI: 1.09-1.93), and exposure to carbapenem and 4th generation cephalosporins (HR:1.57; 95%CI:1.15-2.15), or carbapenem and anti-Pseudomonas penicillins (HR:1.54; 95%CI:1.07-2.22) were responsible for SMA colonization or infection . Sulfamethoxazole/trimethoprim (HR:0.52; 95%CI:0.30-0.90) decreased the chance of 48% of SMA colonization or infections and had protective effect. Carbapenem and 4th generation cephalosporins or anti-Pseudomonas penicillins made independent contribution to SMA colonization or infection. However, carbapenem in combination with 4th generation cephalosporins or anti-Pseudomonas penicillins had no synergistic effects. onclusionsy using data at ward level and patient level from a tertiary hospital in Taiwan, we found the incidence density of SMA colonization or infection was higher at hematological ward than oncology ward. In patients with malignancies, the high burden of such endogenous SMA infection may be attributed to the exposure to more kinds of broad-spectrum antibiotics. Our study demonstrated that 4th generation cephalosporins, anti-Pseudomonas penicillins, and carbapenem make significant contribution to SMA colonization or infection independent of the frequent use of carbapenem. We also found that sulfamethoxazole/trimethoprim was a protective factor for SMA. These findings suggest that to avoid broad-spectrum antibiotic use may prohibit patients from colonization or infection of SMA in the patients with hematologic malignancies. Our time-series design ca be applied to the surveillance of multi-drug resistance.
Subjects
antibiotics
malignancy
time series
ecological study
individual study
multi-level analysis
Type
thesis
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