Antimicrobial Susceptibility Among Organisms from the Asia/Pacific Rim, Europe and Latin and North America Collected As Part of TEST and the in Vitro Activity of Tigecycline

Objectives: To describe antimicrobial susceptibility among bacterial isolates associated with hospital infections collected from 266 centres in Asia/Pacific Rim (n = 1,947), North America (n = 24,283), Latin America (n = 1,957) and Europe (n = 8,796).

Methods: Isolates were collected from blood, respiratory tract, urine, skin, wound, body fluids and other defined sources between January 2004 and August 2006. Only one isolate per patient was accepted. In vitro MICs for the isolates were determined according to the CLSI (formerly NCCLS) guidelines.

Results: Key organisms collected were Acinetobacter baumannii (n = 2,902), Enterobacter spp. (n = 5,731), Escherichia coli (n = 6,504), Klebsiella pneumoniae (n = 4,916), Pseudomonas aeruginosa (n = 5,128), Serratia marcescens (n = 2,313), Enterococcus faecalis (n = 2,701), Enterococcus faecium (n = 1,035) and Staphylococcus aureus (n = 5,753). Rates of methicillin resistance among S. aureus and of vancomycin resistance among enterococci were highest in North America (2,016/3,809, 52.9% and 571/2,544, 22.4%, respectively) and lowest in Europe (337/1,340, 25.1% and 36/916, 3.9%, respectively). Tigecycline was the only antimicrobial to maintain activity against all Gram-positive isolates (MIC(90) values of <or=0.25 mg/L). Overall, tigecycline and imipenem were the most active (>93% susceptibility in all regions) antimicrobials against the Gram-negative species, except for A. baumannii and P. aeruginosa. Piperacillin/tazobactam and amikacin were the most active against P. aeruginosa. Extended-spectrum beta-lactamase producers among K. pneumoniae occurred most frequently in Latin America (124/282, 44.0%).

Conclusions: Tigecycline is a novel broad-spectrum antimicrobial that is active against the common organisms associated with infections.