BACKGROUND: With an increase in the use of colistin methansulfonate (CMS) to treat carbapenem-resistant Acinetobacter baumannii infections, colistin resistance is emerging. METHODS: Patients with infection or colonization due to colistin-resistant A. baumannii were identified at a hospital system in Pennsylvania. Clinical data were collected from electronic medical records. Susceptibility testing, pulsed-field gel electrophoresis (PFGE), and multilocus sequence typing (MLST) were performed. To investigate the mechanism of colistin resistance, lipid A was subjected to matrix-assisted laser desorption/ionization mass spectrometry. RESULTS: Twenty patients with colistin-resistant A. baumannii were identified. Ventilator-associated pneumonia was the most common type of infection. Nineteen patients had received intravenous and/or inhaled CMS for treatment of carbapenem-resistant, colistin-susceptible A. baumannii infection prior to identification of colistin-resistant isolates. The 30-day all-cause mortality rate was 30%. The treatment regimen for colistin-resistant A. baumannii infection associated with the lowest mortality rate was a combination of CMS, a carbapenem, and ampicillin-sulbactam. The colistin-susceptible and -resistant isolates from the same patients were highly related by PFGE, but isolates from different patients were not, suggesting evolution of resistance during CMS therapy. By MLST, all isolates belonged to the international clone II, the lineage that is epidemic worldwide. Phosphoethanolamine modification of lipid A was present in all colistin-resistant A. baumannii isolates. CONCLUSIONS: Colistin-resistant A. baumannii occurred almost exclusively among patients who had received CMS for treatment of carbapenem-resistant, colistin-susceptible A. baumannii infection. Lipid A modification by the addition of phosphoethanolamine accounted for colistin resistance. Susceptibility testing for colistin should be considered for A. baumannii identified from CMS-experienced patients.
BACKGROUND: With an increase in the use of colistin methansulfonate (CMS) to treat carbapenem-resistant Acinetobacter baumannii infections, colistin resistance is emerging. METHODS:Patients with infection or colonization due to colistin-resistant A. baumannii were identified at a hospital system in Pennsylvania. Clinical data were collected from electronic medical records. Susceptibility testing, pulsed-field gel electrophoresis (PFGE), and multilocus sequence typing (MLST) were performed. To investigate the mechanism of colistin resistance, lipid A was subjected to matrix-assisted laser desorption/ionization mass spectrometry. RESULTS: Twenty patients with colistin-resistant A. baumannii were identified. Ventilator-associated pneumonia was the most common type of infection. Nineteen patients had received intravenous and/or inhaled CMS for treatment of carbapenem-resistant, colistin-susceptible A. baumannii infection prior to identification of colistin-resistant isolates. The 30-day all-cause mortality rate was 30%. The treatment regimen for colistin-resistant A. baumannii infection associated with the lowest mortality rate was a combination of CMS, a carbapenem, and ampicillin-sulbactam. The colistin-susceptible and -resistant isolates from the same patients were highly related by PFGE, but isolates from different patients were not, suggesting evolution of resistance during CMS therapy. By MLST, all isolates belonged to the international clone II, the lineage that is epidemic worldwide. Phosphoethanolamine modification of lipid A was present in all colistin-resistant A. baumannii isolates. CONCLUSIONS: Colistin-resistant A. baumannii occurred almost exclusively among patients who had received CMS for treatment of carbapenem-resistant, colistin-susceptible A. baumannii infection. Lipid A modification by the addition of phosphoethanolamine accounted for colistin resistance. Susceptibility testing for colistin should be considered for A. baumannii identified from CMS-experienced patients.
Authors: Jian Li; Roger L Nation; John D Turnidge; Robert W Milne; Kingsley Coulthard; Craig R Rayner; David L Paterson Journal: Lancet Infect Dis Date: 2006-09 Impact factor: 25.071
Authors: Sergio G Bartual; Harald Seifert; Corinna Hippler; M Angeles Domínguez Luzon; Hilmar Wisplinghoff; Francisco Rodríguez-Valera Journal: J Clin Microbiol Date: 2005-09 Impact factor: 5.948
Authors: Neil Woodford; Matthew J Ellington; Juliana M Coelho; Jane F Turton; M Elaina Ward; Susan Brown; Sebastian G B Amyes; David M Livermore Journal: Int J Antimicrob Agents Date: 2006-03-24 Impact factor: 5.283
Authors: F C Tenover; R D Arbeit; R V Goering; P A Mickelsen; B E Murray; D H Persing; B Swaminathan Journal: J Clin Microbiol Date: 1995-09 Impact factor: 5.948
Authors: Sara Marti; Javier Sánchez-Céspedes; M Dolores Blasco; Paula Espinal; Marc Ruiz; Verónica Alba; Jordi Vila Journal: Diagn Microbiol Infect Dis Date: 2008-05-15 Impact factor: 2.803
Authors: Alicia I Hidron; Jonathan R Edwards; Jean Patel; Teresa C Horan; Dawn M Sievert; Daniel A Pollock; Scott K Fridkin Journal: Infect Control Hosp Epidemiol Date: 2008-11 Impact factor: 3.254
Authors: Jennifer M Adams-Haduch; David L Paterson; Hanna E Sidjabat; Anthony W Pasculle; Brian A Potoski; Carlene A Muto; Lee H Harrison; Yohei Doi Journal: Antimicrob Agents Chemother Date: 2008-08-25 Impact factor: 5.191
Authors: Darren Wong; Travis B Nielsen; Robert A Bonomo; Paul Pantapalangkoor; Brian Luna; Brad Spellberg Journal: Clin Microbiol Rev Date: 2017-01 Impact factor: 26.132
Authors: Miao Zhao; Zackery P Bulman; Justin R Lenhard; Michael J Satlin; Barry N Kreiswirth; Thomas J Walsh; Amanda Marrocco; Phillip J Bergen; Roger L Nation; Jian Li; Jing Zhang; Brian T Tsuji Journal: J Antimicrob Chemother Date: 2017-07-01 Impact factor: 5.790
Authors: Deanna J Buehrle; Ryan K Shields; Lloyd G Clarke; Brian A Potoski; Cornelius J Clancy; M Hong Nguyen Journal: Antimicrob Agents Chemother Date: 2016-12-27 Impact factor: 5.191
Authors: Peng Wang; Sarah L Bowler; Serena F Kantz; Roberta T Mettus; Yan Guo; Christi L McElheny; Yohei Doi Journal: J Clin Microbiol Date: 2016-09-14 Impact factor: 5.948
Authors: Laura J Rojas; Madiha Salim; Eric Cober; Sandra S Richter; Federico Perez; Robert A Salata; Robert C Kalayjian; Richard R Watkins; Steve Marshall; Susan D Rudin; T Nicholas Domitrovic; Andrea M Hujer; Kristine M Hujer; Yohei Doi; Keith S Kaye; Scott Evans; Vance G Fowler; Robert A Bonomo; David van Duin Journal: Clin Infect Dis Date: 2017-03-15 Impact factor: 9.079