title: In vitro activity of tigecycline and other tetracyclines against carbapenem-resistant Acinetobacter species: report from a tertiary care centre in Karachi, Pakistan.
abstract: BACKGROUND
  The Aga Khan University Hospital is a tertiary care centre in Karachi, Pakistan, where tigecycline has not been used previously. We report findings of a pre-use in vitro study to evaluate sensitivity of nosocomial Acinetobacter spp. Tigecycline minimum inhibitory concentration (MIC) was correlated with that of other tetracyclines to assess their predictive potential.
  
  
  METHODS
  Acinetobacter spp. were collected from hospitalized inpatients admitted to Aga Khan University Hospital from April to November 2007. Tigecycline, tetracycline, doxycycline, and minocycline MICs were determined by E-test.
  
  
  RESULTS
  One hundred isolates of Acinetobacter spp. were tested. Ninety-eight percent of Acinetobacter spp. were carbapenem-resistant. Tigecycline MIC(50) and MIC(90) were 1.5 and 2.0 microg/ml, respectively. Unavailability of standard breakpoints hindered categorization of these values. Minocycline was highly active, with MIC(90) of 2.0 microg/ml.
  
  
  CONCLUSIONS
  Tigecycline breakpoints for Acinetobacter spp. should be established to prevent injudicious use of this antibiotic based on misleading in vitro results. The therapeutic potential of minocycline needs more in-depth study.
authors.affiliation: Department of Clinical Microbiology, Aga Khan University Hospital, Karachi, Pakistan. sadia.shakkoor @ aku.edu
authors.forename: Sadia
authors.initials: S
authors.lastname: Shakoor
authors.forename: Erum
authors.initials: E
authors.lastname: Khan
authors.forename: Afia
authors.initials: A
authors.lastname: Zafar
authors.forename: Rumina
authors.initials: R
authors.lastname: Hasan
mesh_terms: D000150:Acinetobacter / Q000187:drug effects* / Q000302:isolation & purification / Q000502:physiology; D000151:Acinetobacter Infections / Q000517:prevention & control; D015780:Carbapenems / Q000494:pharmacology*; D024901:Drug Resistance, Multiple, Bacterial / Q000187:drug effects* / Q000502:physiology; D006785:Hospitals, University; D006801:Humans; D008826:Microbial Sensitivity Tests / Q000379:methods; D008911:Minocycline / Q000031:analogs & derivatives* / Q000494:pharmacology; D010154:Pakistan; D013754:Tetracyclines / Q000494:pharmacology*; D000078304:Tigecycline
chemical_list: D015780:Carbapenems; D013754:Tetracyclines; D000078304:Tigecycline; D008911:Minocycline