K. Ishida et al., IN-VITRO AND IN-VIVO ACTIVITIES OF MACROLIDES AGAINST MYCOPLASMA-PNEUMONIAE, Antimicrobial agents and chemotherapy, 38(4), 1994, pp. 790-798
We investigated the in vitro and in vivo activities of macrolides agai
nst Mycoplasma pneumoniae. In vitro MICs of azithromycin, erythromycin
, clarithromycin, and roxithromycin were determined. Azithromycin was
the most potent antimicrobial agent tested in vitro. Its MIC for 90% o
f the strains was 0.00024 mug/ml. MICs for 90% of the strains of eryth
romycin, clarithromycin, and roxithromycin were 0.0156, 0.0078, and 0.
03125 mug/ml, respectively. In vivo activities were assessed in a pulm
onary infection model with Syrian golden hamsters. We evaluated the in
vivo effects on reduction of viable M. pneumoniae cell counts and on
reduction of microscopic and macroscopic histopathologies for azithrom
ycin, erythromycin, and clarithromycin given at 10 mg/kg once daily fo
r 1 and 3 days and given at 15 mg/kg twice daily for 2.5 and 5 days. A
zithromycin was significantly more effective than erythromycin or clar
ithromycin in the same regimens. Especially at 10 mg/kg once daily for
1 day, only azithromycin was significantly effective in the reduction
of viable M. pneumoniae cells and histopathologies. These results sho
w that azithromycin is more efficacious than the other drugs tested ag
ainst M. pneumoniae pneumonia in hamsters. These data suggest that cli
nical studies of macrolides in human patients are warranted.