Efficacy of dalbavancin against methicillin-resistant Staphylococcus aureus in the rat granuloma pouch infection model.
Infections due to methicillin-resistant Staphylococcus aureus (MRSA) are an important cause of morbidity and mortality in hospital patients. Moreover, increased incidences of outpatient MRSA have been recently reported. This study investigated the bactericidal activity of dalbavancin, a novel, semisynthetic glycopeptide antibiotic, against methicillin-sensitive S. aureus (MSSA) and MRSA in the rat granuloma pouch infection model. A single intravenous dose of 10 mg of dalbavancin/kg of body weight reduced the viable MRSA count in pouch exudates by more than 2 log CFU/ml, and regrowth was prevented for up to 120 h. Comparable results with vancomycin required four 100-mg/kg intramuscular doses. With one or two doses of vancomycin, the bacterial load declined over proportionately shorter periods of time, followed by regrowth. Reduction of the bacterial load obtained with 100- and 200-mg/kg oral doses of linezolid was relatively transient, with regrowth starting at 48 h. A single 10-mg/kg dose of dalbavancin reduced the MSSA count at 24 h to below the limit of detection, with no regrowth for at least 96 h. Dalbavancin demonstrated good exudate penetration; the ratio of the area under the curve (AUC) in plasma to the AUC in pouch exudate was 1.01. The in vivo activity of dalbavancin in this model is consistent with the antibiotic concentrations that are reached and maintained for extended periods of time after a single 10-mg/kg dose and with in vitro data showing that these concentrations are bactericidal for staphylococci. The pharmacokinetic and efficacy data seen in this relevant model of infection suggest that dalbavancin may be administered less frequently than vancomycin and linezolid.
Jabés
Daniela
D
Vicuron Pharmaceuticals, 21040 Gerenzano (Varese), Italy. djabes@vicuron.it
Candiani
Gianpaolo
G
Romanó
Gabriella
G
Brunati
Cristina
C
Riva
Simona
S
Cavaleri
Marco
M
D000081:Acetamides / Q000627:therapeutic use; D000818:Animals; D000900:Anti-Bacterial Agents / Q000493:pharmacokinetics / Q000494:pharmacology / Q000627:therapeutic use*; D000890:Anti-Infective Agents / Q000627:therapeutic use; D005260:Female; D006020:Glycopeptides / Q000493:pharmacokinetics / Q000494:pharmacology / Q000627:therapeutic use*; D006099:Granuloma / Q000188:drug therapy* / Q000378:metabolism / Q000382:microbiology; D007273:Injections, Intramuscular; D007275:Injections, Intravenous; D000069349:Linezolid; D008297:Male; D016106:Methicillin Resistance; D008826:Microbial Sensitivity Tests; D023303:Oxazolidinones / Q000627:therapeutic use; D051381:Rats; D017207:Rats, Sprague-Dawley; D013203:Staphylococcal Infections / Q000188:drug therapy* / Q000382:microbiology; D013211:Staphylococcus aureus / Q000187:drug effects; D017334:Teicoplanin / Q000031:analogs & derivatives; D014640:Vancomycin / Q000627:therapeutic use
D000081:Acetamides; D000900:Anti-Bacterial Agents; D000890:Anti-Infective Agents; D006020:Glycopeptides; D023303:Oxazolidinones; D017334:Teicoplanin; D014640:Vancomycin; C469289:dalbavancin; D000069349:Linezolid