An animal model was developed for studying macrolide-resistant Mycobacterium avium complex (MAC) and to measure the effect of ethambutol on resistance. MAC-infected beige mice were given clarithromycin daily; the frequency of clarithromycin-resistant MAC after 8 and 12 weeks was 10(-3) and 10(-2), respectively. Combined ethambutol plus clarithromycin did not increase anti-MAC activity, but clarithromycin-resistant MAC was less frequent (P < .05). The frequency of clarithromycin-resistant MAC in mice receiving the combination was significantly higher than that in untreated mice. These results are consistent with two human trials, which showed that adding ethambutol reduced the frequency of clarithromycin-resistant MAC. Results of the present study suggest that with an initially high level of MAC infection, the addition of ethambutol may only delay resistance. This mouse test system will be useful for investigating the influence of the level of MAC infection and the effect of other drugs on the frequency of resistant MAC.
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http://dx.doi.org/10.1093/infdis/174.6.1218 | DOI Listing |
Microbiol Spectr
February 2023
Department of Microbiology, Faculty of Pharmacy, Meijo University, Nagoya, Japan.
Mycobacterium avium complex (MAC) thrives in various environments and mainly causes lung disease in humans. Because macrolide antibiotics such as clarithromycin or azithromycin are key drugs for MAC lung disease, the emergence of macrolide-resistant strains prevents the treatment of MAC. More than 95% of macrolide-resistant MAC strains are reported to have a point mutation in 23S rRNA domain V.
View Article and Find Full Text PDFCureus
October 2021
Department of Pathology, Saitama Medical Center, Jichi Medical University, Saitama, JPN.
The management of macrolide-resistant complex (MAC) disease is challenging. It is extremely rare for non-human immunodeficiency virus (HIV)-infected patients to develop disseminated MAC disease. A 73-year-old non-HIV-infected woman was diagnosed with MAC lung disease (MAC-LD) for 20 years and subsequently chronic necrotizing pulmonary aspergillosis for three years.
View Article and Find Full Text PDFAnn Thorac Cardiovasc Surg
December 2022
Section of Chest Surgery, Fukujuji Hospital, Kiyose, Tokyo, Japan.
A 48-year-old woman with extensive clarithromycin-resistant Mycobacterium avium complex pulmonary disease (MAC-PD) was successfully treated by left lower lobectomy and lingulectomy following combination treatment of intravenous/inhaled amikacin plus bronchial occlusion by Endobronchial Watanabe Spigots (EWSs). A left pneumonectomy was initially indicated for removing all the lesions, but the procedure would have been barely tolerated by the patient. However, her preoperative combination treatment sufficiently reduced the lesions requiring resection to allow surgical preservation of the left upper division.
View Article and Find Full Text PDFJ Infect Chemother
July 2020
Department of Internal Medicine, National Hospital Organization Kinki-Chuo Chest Medical Center, 1180 Nagasone-Cho, Kita-Ku, Sakai City, Osaka, 591-8555, Japan. Electronic address:
Clinical management of macrolide-resistant Mycobacterium avium complex (MR-MAC) lung disease is difficult. To date, there only exist a limited number of reports on the treatment of clarithromycin-resistant MAC (CR-MAC) lung disease. This study aimed to evaluate prognostic factors and identify effective treatments in CR-MAC lung disease.
View Article and Find Full Text PDFJ Infect Chemother
March 2019
Center for Infectious Diseases and Infection Control, Keio University School of Medicine, Japan. Electronic address:
Background: The optimal duration of antimicrobial therapy for Mycobacterium avium complex lung disease (MAC-LD) is unknown, and recurrence rates are high after treatment discontinuation. Intermittent therapy is recommended for the initial treatment of non-cavitary nodular/bronchiectatic MAC-LD. We hypothesized that intermittent maintenance therapy (IMT) could effectively prevent recurrence after successful treatment of MAC-LD.
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