Title

In vitro Activity of Tigecycline and Other Tetracyclines against Carbapenem-Resistant Acinetobacter Species: Report from a Tertiary Care Centre in Karachi, Pakistan

Document Type

Article

Department

Pathology and Microbiology

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 mu g/ml, respectively. Unavailability of standard breakpoints hindered categorization of these values. Minocycline was highly active, with MIC(90) of 2.0 mu g/ml.

Conclusion:

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.

Publication

Chemotherapy