B. Johnson

P2051 Antibacterial activity of tigecycline against H. influenzae and S. pneumoniae (2004–06) Global Population –T.E.S.T. Program, 2006

Tigecycline na na na 0.12 0.5 32 Ampicillin 76.9 2.1 21.1 32 Cefepime 99.4 0 0.6 32 Ceftriaxone 99.9 0 0.1 32 (n=788) Ampicillin 0 4.6 95.4 32 >32 2 - >32 Cefepime 98.7 0 1.3 32 Ceftriaxone 99.7 0 0.3 8 Ceftriaxone 97.7 1.3 1 64 Imipenem 75.1 21.5 3.4 16 Levofloxacin 99.8 0.2 0 0.5 1 8 Vancomycin 99.9 0 0.1 0.25 0.5 16 Levofloxacin 99.7 0.3 0 0.5 1 8 (n=424) Ceftriaxone 82.5 9.2 8.3 1 2 0.25 - >64 Imipenem 1.2 73.9 24.9 0.5 1 16 Levofloxacin 99.3 0.7 0 1 1 0.25 - 4 Linezolid 100 0 0 8 Vancomycin 99.5 0 0.5 0.25 0.5 <0.12 - 2 MIC (mcg/ml) Tigecycline na 0.12 0.5 na 0.03 0.25 AmoxClav 99.7 0.5 1 95.3 <0.03 1 Ceftriaxone 99.9 <0.06 <0.06 97.7 <0.03 1 Levofloxacin 100 0.015 0.03 99.8 0.5 1 Imipenem 100 0.5 1 75.1 <0.12 0.5 Linezolid -- -- -- 100 <0.5 1 Penicillin -- -- -- 62.4 <0.06 2 S. pneumoniae (n=3,903) H. influenzae (n=3,570)

P1121 Patterns of susceptibility of Gram-negatives/positives isolated in the United Kingdom and Ireland

Tigecycline is a novel antimicrobial with expanded broad-spectrum activity from a new class of compounds, the glycylcyclines. Tigecycline inhibits protein synthesis by binding to the 30S ribosomal subunit. Although it is perceived to be bacteriostatic, its anti-bacterial activity is significant and has shown some bactericidal activity against key targeted pathogens [1,2]. Tigecycline was developed to provide activity against tetracycline and multidrug-resistant gram-positive pathogens and has demonstrated significant broad-spectrum activity against aerobic and anaerobic gram-positive and gram-negative microorganisms [2-4].

P1685 In vitro activity of tigecycline and 10 common therapeutic agents against methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus species – Global Data, 2004 – 2006

Tigecycline is a broad-spectrum antimicrobial agent and firstin-class of the semisynthetic glycylcyclines to be approved for human use [1]. This synthetic analogue of the minocycline molecule exhibits significant antibacterial activity that is both bacteriostatic and, in certain instances, bactericidal with killing activity that is as much as fourfold better than vancomycin and daptomycin [2, 3]. The development of tigecycline is important in that tigecycline and other glycylcyclines are active against bacterial strains carrying either or both of the two major forms of tetracycline resistance: efflux and ribosomal protection. Certain substituents at the 9-position of the tetracycline molecule restored activity against bacteria harboring genes encoding either or both efflux and ribosomal protection. A single chemical modification of tigecycline overcomes the two molecularly distinct forms of resistance while maintaining activity against susceptible gram-positive, gram-negative, aerobic, and anaerobic bacteria [4]. Furthermore, resistance to tigecycline is difficult to produce even in the laboratory.

P2048 Comparison of in vitro activity of tigecycline against pathogens from intensive care patients in Europe –T.E.S.T. Program 2006

Background: Tigecycline, a member of a new class of antimicrobials (glycylcyclines), has been shown to have potent broad spectrum activity against most commonly encountered species responsible for community and hospital acquired infections. The T.E.S.T. program surveyed the in vitro activity of tigecycline from ICU and non-ICU pathogens during 2004 to 2006. Methods: A total of 14,113 clinical isolates from 77 testing sites in 21 European countries were evaluated. Minimum Inhibitory Concentration (MICs) were determined by each site using common broth microdilution panels and interpreted according to EUCAST guidelines. Of these isolates, 2,853 (20.2%) were collected from ICU sources for evaluation. Results: Results are in the table as follows:

P1684 Tigecycline in vitro activity against often difficult to treat European pathogens

Background: Enhanced activity agents such as tigecycline (TIG) may offer antibacterial coverage of common pathogens including multi-drug resistant gram-negatives/positives. The T.E.S.T. program monitored the in vitro activity of TIG and comparators against current European pathogens. Methods: For this study, 77 hospital sites in 21 European countries collected over 14,113 significant isolates from community/ hospital infection sites. MICs were determined to TIG and comparators using broth microdilution panels (EUCAST specified and interpreted). Results: Selected European pathogens tested against tigecycline are shown below: