title: Risk factors and clinical significance of bacteremia caused by Pseudomonas aeruginosa resistant only to carbapenems.
abstract: OBJECTIVE
  Carbapenem-resistant Pseudomonas aeruginosa infections have been a challenge and issue in hospital settings. However, the clinical impact of P. aeruginosa blood isolates resistant only to carbapenems has never been discussed previously.
  
  
  METHODS
  To assess the risk factors and clinical significance of bacteremia caused by carbapenem resistance only P. aeruginosa (CROPA), a 6-year retrospective case-control study was conducted. The CROPA strains were defined as isolates susceptible to ciprofloxacin, antipseudomonal penicillins and cephalosporins, and aminoglycosides but resistant to one antipseudomonal carbapenem (imipenem or meropenem) or both. The controls were selected among patients with bacteremia due to P. aeruginosa susceptible to all above classes of antipseudomonal antibiotics, which was defined as all-susceptible P. aeruginosa.
  
  
  RESULTS
  Twenty-five patients had at least one blood culture positive for CROPA, and 50 controls had all-susceptible P. aeruginosa bacteremia. CROPA bacteremia had a high 30-day mortality rate (72.0%), as compared to 26.0% for the controls (p < 0.001). Through multivariate analysis, carbapenem exposure was the only risk factor for developing CROPA bacteremia (p = 0.002). A comparison between the surviving and deceased patients with CROPA bacteremia showed that nine (50%) of those who died, but none of the survivors, received carbapenems as the initial empirical therapy (p = 0.027).
  
  
  CONCLUSIONS
  Carbapenem exposure was associated with emergence of CROPA infections. Repeated carbapenem use in such patients might increase rates of inappropriate initial empirical treatment and mortality. Prudent carbapenem use is important to reduce the emergence of CROPA.
authors.affiliation: Division of Infectious Diseases, Department of Internal Medicine, Chang Gung Memorial Hospital at Linkou, Chang Gung University College of Medicine, Taoyuan, Taiwan.
authors.forename: Chia-Hsin
authors.initials: CH
authors.lastname: Lee
authors.affiliation: Division of Infectious Diseases, Department of Internal Medicine, Chang Gung Memorial Hospital at Linkou, Chang Gung University College of Medicine, Taoyuan, Taiwan.
authors.forename: Ting-Yi
authors.initials: TY
authors.lastname: Su
authors.affiliation: Division of Infectious Diseases, Department of Internal Medicine, Chang Gung Memorial Hospital at Linkou, Chang Gung University College of Medicine, Taoyuan, Taiwan.
authors.forename: Jung-Jr
authors.initials: JJ
authors.lastname: Ye
authors.affiliation: Division of Infectious Diseases, Department of Internal Medicine, Chang Gung Memorial Hospital at Linkou, Chang Gung University College of Medicine, Taoyuan, Taiwan.
authors.forename: Po-Chang
authors.initials: PC
authors.lastname: Hsu
authors.affiliation: Department of Laboratory Medicine, Chang Gung Memorial Hospital at Linkou, Taoyuan, Taiwan; Department of Medical Biotechnology and Laboratory Science, Chang Gung University, Taoyuan, Taiwan.
authors.forename: An-Jing
authors.initials: AJ
authors.lastname: Kuo
authors.affiliation: Department of Laboratory Medicine, Chang Gung Memorial Hospital at Linkou, Taoyuan, Taiwan; Department of Medical Biotechnology and Laboratory Science, Chang Gung University, Taoyuan, Taiwan.
authors.forename: Ju-Hsin
authors.initials: JH
authors.lastname: Chia
authors.affiliation: Division of Infectious Diseases, Department of Internal Medicine, Chang Gung Memorial Hospital at Linkou, Chang Gung University College of Medicine, Taoyuan, Taiwan. Electronic address: drharrylee@gmail.com.
authors.forename: Ming-Hsun
authors.initials: MH
authors.lastname: Lee
mesh_terms: D000328:Adult; D000368:Aged; D000617:Aminoglycosides / Q000494:pharmacology; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D016470:Bacteremia / Q000188:drug therapy* / Q000382:microbiology / Q000401:mortality; D000071997:Blood Culture; D000073182:Carbapenem-Resistant Enterobacteriaceae / Q000187:drug effects* / Q000472:pathogenicity; D015780:Carbapenems / Q000494:pharmacology*; D016022:Case-Control Studies; D002511:Cephalosporins / Q000494:pharmacology; D002939:Ciprofloxacin / Q000494:pharmacology; D003428:Cross Infection / Q000188:drug therapy / Q000382:microbiology; D005260:Female; D006761:Hospitals; D006801:Humans; D015378:Imipenem / Q000494:pharmacology; D008297:Male; D000077731:Meropenem; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D009026:Mortality; D015999:Multivariate Analysis; D016017:Odds Ratio; D010406:Penicillins / Q000494:pharmacology; D011552:Pseudomonas Infections / Q000097:blood / Q000188:drug therapy* / Q000382:microbiology / Q000401:mortality; D011550:Pseudomonas aeruginosa / Q000187:drug effects* / Q000302:isolation & purification / Q000472:pathogenicity; D012189:Retrospective Studies; D012307:Risk Factors; D012720:Severity of Illness Index; D013624:Taiwan; D013845:Thienamycins / Q000494:pharmacology
chemical_list: D000617:Aminoglycosides; D000900:Anti-Bacterial Agents; D015780:Carbapenems; D002511:Cephalosporins; D010406:Penicillins; D013845:Thienamycins; D002939:Ciprofloxacin; D015378:Imipenem; D000077731:Meropenem
keywords: Pseudomonas aeruginosa; bacteremia; carbapenem resistance; mortality