Preliminary evaluation of the positively and negatively charge effects of tetra-substituted porphyrins on photoinactivation of rapidly growing mycobacteria.

This manuscript reports, at the first time, the photoinactivation evaluation of tetra-cationic and anionic porphyrins as photosensitizers (PS) for the photodynamic inactivation (PDI) of rapidly growing mycobacteria strains. Two different charged porphyrin groups were obtained commercially. PDI experiments in the strains Mycobacterium massiliense e Mycobacterium fortuitum conducted with adequate concentration (without aggregation) of photosensitizer under white light at a fluence rate of 50 mW/cm2 over 90 min showed that the most effective PS caused a 100 times reduction in the concentration of viable mycobacteria. The present results show that porphyrin with positively charge are more efficient PS than anionic porphyrin (negatively charged) against M. massiliense e M. fortuitum. It is also clear that the effectiveness of the molecule as PS for PDI studies with mycobacteria is strongly related with the porphyrin peripheral charge, and consequently their solubility in physiological media. Cationic PSs might be promising anti-mycobacteria PDI agents with potential applications in medical clinical cases and bioremediation.

Chronic otitis media caused by Mycobacterium abscessus spp. massiliense treated with tigecycline in a 10-year-old child.

Mycobacterium abscessus is one of the most pathogenic and chemotherapy-resistant rapidly growing mycobacteria. This Mycobacterium should always be considered as a possible cause of chronic otitis media in children, and treatment might be challenging because of its resistance to multiple antibiotics. There are no reports describing the therapeutic use of tigecycline for the treatment of chronic otitis media caused by M. abscessus. A 10-year-old boy was referred to Tokyo Metropolitan Children's Medical Center with a 7-year history of recurrent otitis media despite treatment with antibiotics and ventilation tubes. Cultures of the otorrhea yielded Mycobacterium abscessus spp. massiliense, and it showed multiple and high-level resistance. The boy required surgery and underwent initial treatment with clarithromycin, amikacin, and tigecycline for 4 weeks. He experienced emesis as a side-effect of tigecycline, which was well controlled with ondansetron. He was treated successfully with 3 months of subsequent oral clarithromycin and linezolid. This is the first pediatric case of chronic otitis media caused by M. abscessus treated with a tigecycline-containing regimen. Although the therapeutic use of tigecycline remains controversial, especially in the pediatric population, it can be an acceptable option in the treatment of chronic otitis media caused by M. abscessus.