Use of in vitro susceptibility and pathogen prevalence data to model the expected clinical success rates of tigecycline and other commonly used antimicrobials for empirical treatment of complicated skin and skin-structure infections

The overall expected coverage for tigecycline and selected antimicrobial regimens based upon prevailing susceptibility rates was evaluated for the empirical therapy of complicated skin and skin-structure infections (cSSSIs). Consecutive, non-duplicate bacterial isolates collected from 2000–2005 from patients with documented cSSSI in 57 medical centres located in the USA (38 centres), France (6 centres), Germany (7 centres), Italy (3 centres) and Spain (3 centres) were used to evaluate the frequency of pathogen occurrence and susceptibility rates of select parenteral antimicrobials (SENTRY Program). By applying pathogen-specific susceptibility rates to the frequency of pathogen occurrence in each country, the overall expected coverage for each treatment regimen was measured. The most frequently isolated pathogens were Staphylococcus aureus (33.3–49.9%), Pseudomonas aeruginosa (8.3–17.2%), Escherichia coli (6.6–13.9%) and enterococci (4.1–8.8%). Tigecycline was highly active against the most common pathogens, except for P. aeruginosa and Proteus mirabilis. The highest overall expected empirical coverage was obtained with combination therapy regimens, including vancomycin plus either imipenem (94.4–99.3%) or piperacillin/tazobactam (92.5–98.2%). Among the monotherapy regimens evaluated, tigecycline provided the highest overall expected coverage in the USA (90.6%), France (89.9%) and Italy (83.3%), whilst piperacillin/tazobactam showed the highest expected coverage in Germany (93.1%) and imipenem in Spain (87.7%). Our results suggest that tigecycline represents a viable additional option for the empirical treatment of cSSSI in these countries.