title: Evaluation of trimethoprim-sulfamethoxazole based combination therapy against Stenotrophomonas maltophilia: in vitro effects and clinical efficacy in cancer patients.
abstract: OBJECTIVE
  The aim of this study was to evaluate the in vitro effects and clinical efficacies of trimethoprim-sulfamethoxazole (SXT) combined with other antimicrobial agents against Stenotrophomonas maltophilia.
  
  
  METHODS
  In vitro analysis was conducted on 89 S. maltophilia strains isolated from blood and the respiratory tract between June 2012 and October 2014. Levofloxacin (LVX), ticarcillin-clavulanic acid (TIM), and minocycline (MIN) were selected for an examination of their effects when individually combined with SXT by the checkerboard method. In addition, 29 S. maltophilia bacteremia cases were reviewed and the clinical efficacies of SXT-based combination therapies were analyzed.
  
  
  RESULTS
  SXT+LVX showed synergy in 21, no interactions in 61, and antagonism in 7. SXT+TIM showed synergy in 71, and no interactions in 18. SXT+MIN showed synergy in 10, and no interactions in 79. The review of clinical data indicated that a combination of SXT+fluoroquinolone was not associated with improved prognosis compared with monotherapy.
  
  
  CONCLUSIONS
  The in vitro data indicated that SXT+TIM had beneficial microbiological effects and was not antagonistic. Our in vitro and clinical data analyses do not support the routine use of SXT+fluoroquinolone combination therapy for S. maltophilia infection.
authors.affiliation: Department of Infectious Diseases, Toranomon Hospital, Tokyo, Japan; Okinaka Memorial Institute for Medical Research, Tokyo, Japan. Electronic address: h-araoka@toranomon.gr.jp.
authors.forename: Hideki
authors.initials: H
authors.lastname: Araoka
authors.affiliation: Department of Infectious Diseases, Toranomon Hospital, Tokyo, Japan.
authors.forename: Masaru
authors.initials: M
authors.lastname: Baba
authors.affiliation: Department of Infectious Diseases, Toranomon Hospital, Tokyo, Japan.
authors.forename: Chikako
authors.initials: C
authors.lastname: Okada
authors.affiliation: Department of Infectious Diseases, Toranomon Hospital, Tokyo, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Abe
authors.affiliation: Department of Infectious Diseases, Toranomon Hospital, Tokyo, Japan.
authors.forename: Muneyoshi
authors.initials: M
authors.lastname: Kimura
authors.affiliation: Department of Infectious Diseases, Toranomon Hospital, Tokyo, Japan; Okinaka Memorial Institute for Medical Research, Tokyo, Japan.
authors.forename: Akiko
authors.initials: A
authors.lastname: Yoneyama
mesh_terms: D000368:Aged; D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D016470:Bacteremia / Q000188:drug therapy; D002969:Clavulanic Acids; D004359:Drug Therapy, Combination; D005260:Female; D024841:Fluoroquinolones / Q000627:therapeutic use; D016905:Gram-Negative Bacterial Infections / Q000150:complications / Q000188:drug therapy* / Q000382:microbiology; D006801:Humans; D064704:Levofloxacin / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D008911:Minocycline / Q000627:therapeutic use; D009369:Neoplasms / Q000150:complications* / Q000188:drug therapy; D020615:Stenotrophomonas maltophilia / Q000302:isolation & purification; D013982:Ticarcillin; D016896:Treatment Outcome; D015662:Trimethoprim, Sulfamethoxazole Drug Combination / Q000627:therapeutic use*
chemical_list: D000900:Anti-Bacterial Agents; D002969:Clavulanic Acids; D024841:Fluoroquinolones; D064704:Levofloxacin; D015662:Trimethoprim, Sulfamethoxazole Drug Combination; C043215:ticarcillin-clavulanic acid; D013982:Ticarcillin; D008911:Minocycline
keywords: Stenotrophomonas maltophilia; cancer patients; combination therapy; fluoroquinolones; ticarcillin-clavulanic acid; trimethoprim-sulfamethoxazole