The Journal of antimicrobial chemotherapy
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J. Antimicrob. Chemother. · Jul 1995
Acquired resistance in Mycobacterium avium complex strains isolated from AIDS patients and beige mice during treatment with clarithromycin.
Clarithromycin has been reported to select clarithromycin resistant mutants of Mycobacterium avium complex (MAC) during treatment with clarithromycin in AIDS patients and beige mice. We selected resistant mutants in vitro at a frequency of 5 x 10(-9). ⋯ In contrast, the pattern of resistance to non-macrolide antibiotics remained unchanged in clarithromycin resistant strains. A dramatic decrease in ribosome affinity for clarithromycin and erythromycin was found in clarithromycin resistant strains, but no mutation was found in the peptidyl domain of the 23S rRNA, indicating that another ribosomal modification is involved.