title: Outcome of infections due to pandrug-resistant (PDR) Gram-negative bacteria.
abstract: BACKGROUND
  The increasing problem of infections due to multidrug-resistant Gram-negative bacteria has led to re-use of polymyxins in several countries. However, there are already clinical isolates of Gram-negative bacteria that are resistant to all available antibiotics, including polymyxins.
  
  
  METHODS
  We present a case series of patients with infections due to pathogens resistant to all antimicrobial agents tested, including polymyxins. An isolate was defined as pandrug-resistant (PDR) if it exhibited resistance to all 7 anti-pseudomonal antimicrobial agents, i.e. antipseudomonal penicillins, cephalosporins, carbapenems, monobactams, quinolones, aminoglycosides, and polymyxins.
  
  
  RESULTS
  Clinical cure of the infection due to pandrug-resistant (PDR) Gram-negative bacteria, namely Pseudomonas aeruginosa or Klebsiella pneumoniae was observed in 4 out of 6 patients with combination of colistin and beta lactam antibiotics.
  
  
  CONCLUSIONS
  Colistin, in combination with beta lactam antibiotics, may be a useful agent for the management of pandrug-resistant Gram-negative bacterial infections. The re-use of polymyxins, an old class of antibiotics, should be done with caution in an attempt to delay the rate of development of pandrug-resistant Gram-negative bacterial infections.
authors.affiliation: Alfa Institute of Biomedical Sciences, Athens, Greece. matthew.falagas@tufts.edu
authors.forename: Matthew E
authors.initials: ME
authors.lastname: Falagas
authors.forename: Ioannis A
authors.initials: IA
authors.lastname: Bliziotis
authors.forename: Sofia K
authors.initials: SK
authors.lastname: Kasiakou
authors.forename: George
authors.initials: G
authors.lastname: Samonis
authors.forename: Panayiota
authors.initials: P
authors.lastname: Athanassopoulou
authors.forename: Argyris
authors.initials: A
authors.lastname: Michalopoulos
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use*; D024901:Drug Resistance, Multiple, Bacterial; D005260:Female; D016905:Gram-Negative Bacterial Infections / Q000188:drug therapy* / Q000382:microbiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D016896:Treatment Outcome
chemical_list: D000900:Anti-Bacterial Agents