Antimicrobial susceptibility and combination testing of invasive Stenotrophomonas maltophilia isolates. (April 2013)

• Record Type: Journal Article
• Authors: Church, Deirdre; Lloyd, Tracie; Peirano, Gisele; Pitout, Johann
• Is Part Of: Scandinavian journal of infectious diseases. Volume 45:Number 4(2013:Apr.)
• Page Start: 265
• Page End: 270
• Publication Date: 2013-04
• Subjects: Communicable diseases -- Periodicals; Infection -- Periodicals; 616.9
• DOI: 10.3109/00365548.2012.732240
• Languages: English
• ISSNs: 0036-5548

Abstract

<abstract> <title>Abstract</title> <p> <italic>Background:</italic> Treatment of invasive <italic>Stenotrophomonas maltophilia</italic> infections is difficult due to this organism's inherent multidrug resistance and increasing resistance to trimethoprim–sulfamethoxazole via acquisition of the <italic>sul</italic> genes. <italic>Methods:</italic> In vitro antibiotic susceptibility testing was performed using a customized broth microdilution panel. Combination testing for tigecycline with anti-Stenotrophomonas agents (i.e. colistin, ticarcillin–clavulanate, ceftazidime, and levofloxacin) was done using the cross Etest method. Genotyping was done using automated repetitive PCR. <italic>Results:</italic> A total of 90 patients with invasive <italic>S. maltophilia</italic> infections included: (79%) adults, and 21% children or infants [6/12 (50%) cases occurred in infants aged ≤ 1 year.]. <italic>S. maltophilia</italic> isolates were recovered from blood (69%), lower respiratory (21%) or other sites (CSF, peritoneal fluid) (11%). Seventeen percent of the isolates were SXT-R, and also demonstrated multi-drug resistant to two or more antibiotic classes. Minocycline, tigecycline and colistin had the best in vitro activities. The combination testing of tigecycline and colistin gave the best results; 12 isolates were tested and synergy occurred in 3 isolates while an additional 7 isolates showed additive results. <italic>Conclusions:</italic> We recommend further evaluation with killing assays and clinical studies to evaluate the effectiveness of tigecycline and colistin combination for invasive <italic>S. maltophilia</italic> infections.</p> </abstract>