Resistance of Mycoplasma pneumoniae to erythromycin and other antibiotics

A case is reported of a 14-year-old girl who had M. pneumoniae pneumonia, and in whom the resistance of the organism increased suddently from a minimal inhibitory concentration of erythromycin of 0.008 to 400 γ per milliliter 2 weeks after the beginning of erythromycin therapy. At the same time the organism developed resistance to oleandomycin, spiramycin, leucomycin, josamycin, and lincomycin. The clinical course was uneventful in spite of the emergence of resistance; the radiologic findings returned to normal 3 weeks after the beginning of erythromycin therapy.