Comparative In Vitro Activity of Tigecycline Against Bacteria Recovered from Clinical Specimens in Latin America

The present study was performed to evaluate the in vitro activity of tigecycline in comparison to other agents against isolates recovered from patients hospitalized in Latin American. Organisms were collected in 47 clinical laboratories from 4 countries of Latin America between November 2005 and October 2006 and were tested by using disk diffusion method as described by the CLSI. A total of 7966 isolates were assessed. Tigecycline proved highly active against staphylococci and enterococci (>99% susceptibility). Imipenem was the most active agent against Escherichia coli (100% susceptibility), followed by tigecycline, 98.6% susceptibility. Resistance to cefotaxime in this species was 15.3%. Global tigecycline susceptibility of Klebsiella species was 90.2%, but the susceptibility rate was significantly slower in Venezuela (82%) than in Argentina, Colombia and Chile (93%) (p<0.01). Global cefotaxime resistance to Klebsiella spp. was 32.2% and carbapenem resistance was detected in all countries. By adopting a susceptible breakpoint >= 16mm, 91.3% of the Acinetobacter isolates proved susceptible to tigecycline. Results from the present study suggest that tigecycline may be a suitable option in Latin America, a region where multidrug resistance seems to be a dramatic, increasing problem and new antimicrobial choices are urgently needed.