The molecular epidemiology of Stenotrophomonas maltophilia bacteraemia in a tertiary referral hospital in the United Arab Emirates 2000-2004

Abstract

Background: Stenotrophomonas maltophilia is recognised as an important cause of nosocomial infection, especially in immunocompromised patients, resulting in significant morbidity and mortality. The treatment of S. maltophilia infection presents a therapeutic challenge. The precise modes of transmission of S. maltophilia in the hospital environment are not known and such knowledge is essential to target interventions to prevent spread. There are few published data on the patterns of nosocomial infection in the United Arab Emirates (UAE). A recent study showed that S. maltophilia is an established cause of bloodstream infection in Tawam Hospital in the UAE. Little is known about its epidemiology in the hospital.

Methods: We describe the clinical characteristics of 25 episodes of S. maltophilia bacteraemia which occurred from 2000-2004. The strains were characterised using pulsed field gel electrophoresis (PFGE).

Results: All episodes were hospital-acquired and malignancy and central venous catheters were predisposing factors. Catheter-associated infection comprised 88% infection. Catheter removal was important for the successful management of catheter-associated infection. The results of PFGE suggested that there were as many strains as patients. S. maltophilia strains isolated from the same patient had indistinguishable PFGE profiles.

Conclusion: PFGE is a valid and reproducible typing method for S. maltophilia. The precise sources and modes of spread of S. maltophilia in the hospital are still not known. Knowledge that person to person transmission was not a major mode of transmission enabled infection control interventions for S. maltophilia to be targeted more effectively.

Figure 1

Pulsed field gel electrophoresis (PFGE) patterns of the Stenotrophomonas maltophilia strains. T 46/9 and T 49/4 are isolates from patient 21 on Table 2. T 27/15, T 44/6, B6/2, B6/5 are isolates from patient 17 on Table 2. V3192 and V2067 represent patients 6 and 9 respectively on Table 2.