ru-66647 and Mycobacterium-avium-intracellulare-Infection

This review discusses the clinicoradiological findings of community-acquired respiratory infections and the treatment strategy for respiratory infections. To make a differential diagnosis between bacterial pneumonia, pneumonia caused by atypical pathogens, and mycobacterial infections, it is very important to analyze the radiological findings of inflammatory lung diseases based on normal antomical structures. If clinicoradiological anlyses could make these differentiations, the appropriate treatment strategy for respiratory infections could be established. To accomplish this, exact orientations of pulmonary lobulus, acinus, and respiratory bronchioles is very important. Then, through analyzing chest CT findings and distribution patterns based on normal anatomical structures, estimation of causative pathogens could be possible. Especially, whether inflammatory exudates could pass Kohn's pores as well as Lambert's channel or not is very important factor to affect radiological findings of several pneumonia (as traditionally called "segmental" and "nonsegmental" distribution). To differentiate infections caused by Mycobacterium tuberculosis from nontuberculous mycobacteria, several important criteria have been demonstrated. Briefly, it has been suggested that Mycobacterium avium complex (MAC) respiratory infection is increasing especially in elderly women without underlying diseases. In MAC respiratory infection, right middle lobe and left lingula are frequently involved and centrilobular nodules and diffuse bronchiectases are characteristic radiological findings. Finally, the role of telithromycin in the treatment of respiratory infections is discussed.

Topics: Anti-Bacterial Agents; Community-Acquired Infections; Diagnosis, Differential; Humans; Ketolides; Mycobacterium avium-intracellulare Infection; Mycobacterium Infections, Nontuberculous; Pneumonia, Bacterial; Radiography, Thoracic; Respiratory Tract Infections

The activity of telithromycin, a new ketolide, was evaluated in vitro and in vivo against Mycobacterium avium complex (MAC) strains. The MIC of telithromycin for several M. avium isolates obtained from the blood of AIDS patients ranged from 16 to >128 microg/ml (MIC at which 90% of isolates are inhibited, >128 microg/ml), and the compound did show activity in the macrophage system at concentrations greater than 8 or 16 microg/ml, but this was dependent on the MAC strain used. Telithromycin was then administered to mice infected with MAC strain 101 for 4 weeks at doses of 100, 200, or 400 mg/kg of body weight/day. Treatment with 100 and 200 mg/kg/day was bacteriostatic, but at 400 mg/kg/day telithromycin was bactericidal for MAC strains. The frequency of the emergence of resistance to telithromycin was low despite prolonged usage (12 weeks). This study demonstrates that telithromycin is active in vivo against MAC and warrants further evaluation.

Topics: Animals; Anti-Bacterial Agents; Dose-Response Relationship, Drug; Drug Resistance; Female; Humans; Ketolides; Macrolides; Macrophages; Mice; Mice, Inbred C57BL; Microbial Sensitivity Tests; Mycobacterium avium Complex; Mycobacterium avium-intracellulare Infection