title: Successful Colistin Treatment of Multidrug-Resistant Pseudomonas aeruginosa Infection Using a Rapid Method for Determination of Colistin in Plasma: Usefulness of Therapeutic Drug Monitoring.
abstract: A 56-year-old woman with systemic lupus erythematosus had bacteremia due to multidrug-resistant Pseudomonas aeruginosa (MDRP). She was initially treated with imipenem-cilastatin, tobramycin, and aztreonam; however, MDRP was still detected intermittently in her plasma. Multidrug-susceptibility tests demonstrated that MDRP was susceptible only to colistin. Therefore, in addition to these antibiotics, the administration of intravenous colistin methanesulfonate, a prodrug formula of colistin, was started at a daily dose of 2.5 mg/kg (as colistin base activity). The initial dose setting was based on the patient's renal function (baseline creatinine clearance=32.7 mL/min). After initiating colistin, the patient's C-reactive protein levels gradually decreased. Blood cultures showed no evidence of MDRP on days 8, 14, and 22 after colistin initiation. However, the patient's renal function went from bad to worse owing to septic shock induced by methicillin-resistant Staphylococcus aureus (MRSA) infection. A few days later, the trough plasma levels of colistin were 7.88 mg/L, which appeared to be higher than expected. After decreasing the colistin dose, the patient's renal function gradually improved. On the final day of colistin treatment, the plasma levels decreased to 0.60 mg/L. MDRP could not be detected in blood culture after colistin treatment. Therefore, we successfully treated a case of bloodstream infection due to MDRP by therapeutic drug monitoring (TDM) of colistin. It is suggested that the monitoring of blood colistin levels by liquid chromatography-tandem mass spectrometry can contribute to safer, more effective antimicrobial therapy of MDRP because TDM facilitates quick decisions on dose adjustments.
authors.affiliation: Department of Pharmacy, Hokkaido University Hospital.
authors.forename: Takehiro
authors.initials: T
authors.lastname: Yamada
authors.forename: Nobuhisa
authors.initials: N
authors.lastname: Ishiguro
authors.forename: Kenji
authors.initials: K
authors.lastname: Oku
authors.forename: Issei
authors.initials: I
authors.lastname: Higuchi
authors.forename: Ikuma
authors.initials: I
authors.lastname: Nakagawa
authors.forename: Atsushi
authors.initials: A
authors.lastname: Noguchi
authors.forename: Shinsuke
authors.initials: S
authors.lastname: Yasuda
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Fukumoto
authors.forename: Sumio
authors.initials: S
authors.lastname: Iwasaki
authors.forename: Kouji
authors.initials: K
authors.lastname: Akizawa
authors.forename: Ayako
authors.initials: A
authors.lastname: Furugen
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Yamaguchi
authors.forename: Ken
authors.initials: K
authors.lastname: Iseki
mesh_terms: D000900:Anti-Bacterial Agents / Q000097:blood* / Q000493:pharmacokinetics / Q000627:therapeutic use*; D016470:Bacteremia / Q000097:blood / Q000188:drug therapy*; D003091:Colistin / Q000097:blood* / Q000493:pharmacokinetics / Q000627:therapeutic use*; D016903:Drug Monitoring; D024901:Drug Resistance, Multiple, Bacterial; D005260:Female; D006801:Humans; D008875:Middle Aged; D011552:Pseudomonas Infections / Q000097:blood / Q000188:drug therapy*; D011550:Pseudomonas aeruginosa; D016896:Treatment Outcome
chemical_list: D000900:Anti-Bacterial Agents; D003091:Colistin