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German surveillance study on the in vitro activity of daptomycin against Gram-positive cocci

Abstract number: P1723

Kresken M., Brauers J.

Objectives: Drug resistance (R) in Gram+ bacteria has become an increasing problem over the past 20 years. New antimicrobial agents such as the lipopeptide daptomycin (DAP) have been developed to address this problem. Shortly after the approval of DAP in the EU, a surveillance study was started by a network of 73 laboratories to monitor the susceptibility of Gram+ bacteria to DAP in Germany. The objective of this study was to evaluate the susceptibility of isolates of six clinically important Gram+ species to DAP and other antimicrobial agents.

Methods: A total of 2,646 isolates incl. meticillin-susceptible S. aureus (MSSA, n = 661), meticillin-resistant S. aureus (MRSA, n = 439), S. epidermidis (Se, n = 425), E. faecalis (Es, n = 341), E. faecium (Em, n = 324), S. pyogenes (Spy, n = 319) and S. agalactiae (Sag, n = 137) were tested against DAP, linezolid (LZD), vancomycin (VAN) and other drugs. Primary isolates obtained from hospitalised patients with skin and soft tissue infections, respiratory tract infections, foreign body/catheter infections or sepsis were included. MICs were determined in a central laboratory using the microdilution method according to the German DIN standard. For DAP, the Ca2+ concentration of the test solution was adjusted to 50 mg/L. MICs were interpreted by EUCAST criteria, when possible.

Results: Isolates were primarily recovered from wound swabs (65%), blood samples (21%) and respiratory specimens (9%). MIC50/90s of DAP for MSSA, MRSA, and Se each were 0.5/1 mg/L. All but one isolates were inhibited by DAP at the breakpoint of 1 mg/L. The remaining isolate had an MIC of 2 mg/L. All staphylococci were susceptible to LZD and VAN. The highest MIC of VAN for MRSA was 2 mg/L. Based on MIC50/90s, DAP was up to 4-times more active than LZD or VAN against staphylococci.

Of the Em and Es isolates, 33 (10%) and one (0.3%) were R to VAN, respectively. DAP inhibited all strains at 4 mg/L. One Es isolate was resistant to LZD (MIC 32 mg/L). High-level R to gentamicin (MIC > 500 mg/L) was observed in 35/42% of Es/Em isolates.

DAP, with an MIC50/90 of 0.125/0.25 mg/L, was more active than LZD (1/1 mg/L) or VAN (0.25/0.5 mg/L) against Spy. Against Sag, DAP (0.5/1 mg/L) was more active than LZD (1/2 mg/L) and comparably active to VAN (0.5/0.5 mg/L). R to erythromycin was detected in 9% of Spy isolates and 20% of Sag isolates.

Conclusions: DAP demonstrated excellent in vitro activity against a large collection of German Gram+ cocci including MRSA and VRE.

Session Details

Date: 19/04/2008
Time: 00:00-00:00
Session name: 18th European Congress of Clinical Microbiology and Infectious Diseases
Subject:
Location: Barcelona, Spain
Presentation type:
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