In Vitro Activity of Tigecycline Against Multi Drug Resistant Bacteria

Objective: To determine in vitro efficacy of tigecycline against multi-drug resistant bacteria. Study design: Descriptive cross-sectional study. Place and duration of study: Department of Microbiology, Army Medical College/Armed Forces Institute of Pathology, Rawalpindi over a period of two years. Materials and Methods: Methicillin resistant Staphylococcus aureus were identified by using cefoxitin 30μg disc. Extended spectrum β lactamase producers were detected employing double disc synergy test. Whereas detection of vancomycin resistant enterococci was done using E-strips of vancomycin. Susceptibility of the isolates to tigecycline was done by employing modified Kirby Bauer disk diffusion technique. Minimum inhibitory concentrations of the isolates were determined by using E-strips (bioMerieux) of tigecycline. Results were interpreted according to recommendations. Results: All methicillin resistant Staphylococcus aureus isolates were sensitive to tigecycline. All extended spectrum β-lactamase producers (100%) were susceptible to tigecycline by modified Kirby-Bauer disk diffusion technique but (97.5%) by E-strip method. All vancomycin resistant enterococci (100%) were susceptible to tigecycline. Conclusion: The results demonstrated that tigecycline, has excellent in vitro activity against MDR bacteria. This drug is thus a promising therapeutic option in an era of rapidly growing antibiotic resistance.