Extensively drug-resistant Stenotrophomonas maltophilia in a tertiary care hospital in Taiwan: microbiologic characteristics, clinical features, and outcomes

• Published in: Diagnostic microbiology and infectious disease 2008-02, Vol.60 (2), p.205-210
• Main Authors: Tan, Che-Kim, Liaw, Shwu-Jen, Yu, Chong-Jen, Teng, Lee-Jene, Hsueh, Po-Ren
• Format: Article
• Language: English
• Subjects: Aged; Aged, 80 and over; Bacteremia - epidemiology; Bacteremia - microbiology; Bacteremia - mortality; Bacterial Typing Techniques; Bacteriology; Biological and medical sciences; Clinical features; Cluster Analysis; Colonization; Cross Infection - epidemiology; Cross Infection - microbiology; Drug Resistance, Multiple, Bacterial; Extensively drug resistant; Female; Fundamental and applied biological sciences. Psychology; Genotype; Gram-Negative Bacterial Infections - epidemiology; Gram-Negative Bacterial Infections - microbiology; Gram-Negative Bacterial Infections - mortality; Hospitals; Humans; Infection; Infectious Disease; Internal Medicine; Male; Microbiology; Middle Aged; Miscellaneous; Outcomes; Pneumonia - epidemiology; Pneumonia - microbiology; Pneumonia - mortality; Stenotrophomonas maltophilia; Stenotrophomonas maltophilia - drug effects; Stenotrophomonas maltophilia - isolation & purification; Taiwan - epidemiology
• ISSN: 0732-8893; 1879-0070
• DOI: 10.1016/j.diagmicrobio.2007.09.007

Abstract A retrospective study was performed in a university-affiliated referral center from year 1999 to year 2004 to understand the trend of resistance in Stenotrophomonas maltophilia isolates associated with nosocomial infections and describe the emergence of an extensively drug-resistant S. maltophilia (XDRSM). A 49% increase in all types of nosocomial infections and an 85% increase in nosocomial bloodstream infections caused by S. maltophilia were noted over the 5-year period. Trends of resistance to 7 antimicrobial agents against S. maltophilia remained stable. Seventeen patients had positive cultures of XDRSM in the year 2004, including 6 with pneumonia and 1 with biliary tract infection, and the other 10 patients had XDRSM colonization. Twelve patients (70.6%) had positive cultures of non-XDRSM prior to the acquisition of XDRSM. The mortality rate of patients with XDRSM infection was higher than those with colonization (85.7% versus 10%, P = 0.004). XDRSM infection, presence of shock, and the number of dysfunctional organ systems at the time of XDRSM isolation were significantly associated with in-hospital mortality ( P < 0.05). Genotyping of the 17 XDRSM isolates revealed 16 different clones. All the isolates tested possessed class 1 integron and formed biofilms and melanin. The high genotypic heterogeneity among XDRSM isolates was indicative of the polyclonal nature of emergence of these resistant bacteria. Majority of patients had positive cultures of non-XDRSM prior to the acquisition of XDRSM, indicating that the use of antibiotics might have resulted in selection of XDRSM.