Therapeutic efficacy of azithromycin, clarithromycin, minocycline and tosufloxacin against macrolide-resistant and macrolide-sensitive Mycoplasma pneumoniae pneumonia in pediatric patients.

OBJECTIVE: To clarify therapeutic effects of azithromycin, clarithromycin, minocycline and tosufloxacin against macrolide-resistant Mycoplasma pneumoniae (MRMP) pneumonia and against macrolide-sensitive Mycoplasma pneumoniae (MSMP) pneumonia in pediatric patients. METHODS: A prospective, multicenter observational study was conducted from July 2013 to August 2015. The therapeutic effects of azithromycin, clarithromycin, minocycline and tosufloxacin were evaluated in 59 patients with pneumonia caused by MRMP and in 50 patients with pneumonia caused by MSMP. In vitro activities of antimicrobial agents against isolates of Mycoplasma pneumoniae were also measured. RESULTS: Mean durations of fever following commencement of treatment in patients infected with MRMP and MSMP were 5.2 and 1.9 days, respectively (log-rank test, P < 0.0001). Among patients infected with MRMP, mean durations of fever were 4.6, 5.5, 1.0 and 7.5 days for patients treated with azithromycin, clarithromycin, minocycline and tosufloxacin, respectively (log-rank test, P < 0.0001). Among patients infected with MSMP, mean durations of fever were 2.5, 1.7, 0.9 and 4.3 days for patients treated with azithromycin, clarithromycin, minocycline and tosufloxacin, respectively (log-rank test, P = 0.0162). The MIC90s of azithromycin and clarithromycin among the 27 isolates of MRMP were 64 and 256 µg/ml, respectively, and those among the 23 isolates of MSMP were <0.000125 and 0.001 µg/ml, respectively. The MIC90s of minocycline and tosufloxacin among the 27 isolates of MRMP were 1.0 and 0.25 µg/ml, respectively, and those among the 23 isolates of MSMP were 1.0 and 0.5 µg/ml, respectively. CONCLUSION: Both minocycline and tosufloxacin showed good in vitro activities against MRMP. Minocycline, but not tosufloxacin, shortened the duration of fever in pediatric patients infected with MRMP compared to the duration of fever in patients treated with macrolides.

[Usefulness of parenteral colistin in treating of lower respiratory infection due to multidrug-resistant Pseudomonas aeruginosa].

We report a case of cystic fibrosis in a 19-year-old woman who suffered from frequent exacerbations of lower respiratory infection due to multidrug-resistant Pseudomonas aeruginosa and who was successfully treated with parenteral colistin. Multidrug-resistant Pseudomonas aeruginosa isolated from sputum had become resistant to all parenteral antibiotics commercially available in Japan. She did not show clinical improvement despite treatment with several different combinations of available antibiotics. We therefore obtained parenteral colistin from a pharmacy outside Japan. She responded well to parenteral colistin without apparent side effects such as serious nephrotoxicity or neurotoxicity. Colistin is therefore an important alternative antibiotic for treating multidrug-resistant Pseudomonas aeruginosa and its use should be considered in severe infection. We hope that parenteral colistin will become available in Japan in the near future.