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Antimicrobial Agents and Chemotherapy, April 2000, p. 1010-1018, Vol. 44, No. 4
Centre de Recherche en Infectiologie,
Université Laval, Sainte-Foy, Québec, Canada G1V 4G2
Received 8 July 1999/Returned for modification 31 October
1999/Accepted 12 January 2000
The effectiveness of ziracin (SCH27899), a novel everninomicin, was
at first investigated against lethal pneumonia caused by a
penicillin-susceptible Streptococcus pneumoniae strain. A single intravenous injection of ziracin at a dose of 60 mg/kg of body
weight given at 18 h postinfection protected 100% mice and led to
the complete clearance of bacteria from their lungs. The activity of
ziracin was observed to be the same as that of ceftriaxone: the 50%
protective doses (PD50s) of ziracin and ceftriaxone were
24.8 and 24.6 mg/kg, respectively. Evaluation of this therapy with
leukopenic mice showed that a single injection of ziracin protected
75% of these mice. A delay in therapy with ziracin, which was
initiated at 48 h postinfection with 30 mg/kg given once daily for
3 days, resulted in an 83% survival rate of immunocompetent mice. The
efficacy of ziracin was further compared to that of vancomycin against
lethal pneumonia caused by a penicillin-resistant S. pneumoniae strain in leukopenic mice. The PD50s of
ziracin and vancomycin were 40.5 and 44.2 mg/kg, respectively.
Treatment with ziracin at 30 mg/kg once daily for 2 days (initiated 18 h postinfection) yielded an 83% survival rate and achieved complete eradication of the bacteria. The results were the same as those obtained with vancomycin administered at 15 mg/kg twice daily for 2 days. It is notable that the high survival rates for mice treated with
ziracin were associated with effective eradication of the bacteria and
rapid recovery of pulmonary tissues from pneumonia. The pharmacokinetic
properties of ziracin, ceftriaxone, and vancomycin were estimated
following intravenous administration of a single dose of 30 mg/kg to
immunocompetent mice. The half-life of ziracin was observed to be
longer than those of ceftriaxone and vancomycin (2.3 h versus 1.0 and
0.36 h in the bloodstream and 3 h versus 1.9 and 0.45 h
in lung tissues). The areas under the concentration-time curves (AUCs)
in lung tissue for ziracin versus those for ceftriaxone and vancomycin
were 36 µg · h/g versus 20 and 9.5 µg · h/g. The prolonged half-life and high AUC for ziracin in tissue contributed to
its excellent in vivo activities.
0066-4804/00/$04.00+0
Copyright © 2000, American Society for Microbiology. All rights reserved.
In Vivo Activity and Pharmacokinetics of Ziracin
(SCH27899), a New Long-Acting Everninomicin Antibiotic, in a Murine
Model of Penicillin-Susceptible or Penicillin-Resistant
Pneumococcal Pneumonia
*
Corresponding author. Mailing address: Centre de
Recherche en Infectiologie, Centre Hospitalier de l'Université
Laval, 2705 Boul. Laurier, Sainte-Foy, Québec, Canada G1V 4G2.
Phone: (418) 654-2705. Fax: (418) 654-2715. E-mail:
Michel.G.Bergeron{at}crchul.ulaval.ca.
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