[Tympanostomy tube otorrhea: microbiological epidemiology, pathogen susceptibility to local antibiotics and bactericidal power of the rifamycin-olfloxacin combination].

OBJECTIVE

We studied the microbiological epidemiology of tympanostomy tube otorrhea, rifamycin and ofloxacin sensitivity of pathogens isolated from these otorrheas, and the bactericidal power of the rifamycine-ofloxacin combination.

MATERIAL AND METHODS

A prospective study was conducted in 1997 with cultures of otorrhea aspirates, in vitro study of pathogen resistance to rifamycin and ofloxacin, bacteriocidal study of the rifamycin-ofloxacin combination.

RESULTS

One hundred eight aspirates were obtained from 98 children (mean age 5 years). Ten aspirates were sterile, 32 had more than one pathogen. The more frequent pathogens were Pseudomonas aeruginosa (Pa) (n=35), Staphylococcus aureus (Sa) (n=27), Haemophilus influenae (Hi) (n=12) and Streptococcus pneumoniae (Sp) (n=9). All Hi, all Sp, 86.3% of the Sa (MIC(90) 0.25 mg/l) and none of the Pa were rifamycin sensitive. All Hi, 97.7% of the Pa (MIC(90) 0.5 mg/l), 73,1% of the Sa (MIC(90) 0.24 mg/l) and none of the Sp were ofloxacin sensitive. The rifamycin-ofloxacin combination led to a 4 log CFU/ml decrease in 6 hours for Sp, and in 24 hours for Pa, Hi and Sa.

CONCLUSION

The rifamycin-ofloxacin combination is bactericidal for bacteria causing tympanostomy tube otorrhea. Otic drops with this combination should be considered as the first line treatment for such otorrhea.