Abstract
Objective: Posttympanostomy tube (TT) otorrhea has been linked to microbial biofilms. TTs may be exposed to a wide range of microbes. The purpose of this study was to compare the TT-biofilm forming propensity of common otopathogens, Pseudomonas aeruginosa (PA), Staphylococcus aureus (SA), Haemophilus influenzae (HI), and Streptococcus pneumoniae (SP).
Method: Fluoroplastic coupons were exposed to plasma and cultured with 3 strains of PA, SA, HI, or SP for 2, 4, or 7 days. Half of the coupons were treated with antibiotics to kill planktonic bacteria. Total and biofilm colony counts and electron microscopy were performed.
Results: SA formed mature biofilm after 2 days, not different from 4- or 7-day biofilms (P > .05), and was most tolerant to antibiotic treatment. PA also formed biofilms at 2 days, reached a plateau at 4 days (P > .05), and decreased at 7 days (P < .01). HI formed biofilm only after 4 days (P ≤ .04). SP did not form biofilm without catalase supplementation. With catalase, one SP strain showed a delay in biofilm formation similar to HI (P < .0001) while the other 2 strains formed biofilms after 2 days.
Conclusion: TT biofilm formation occurs with common middle ear pathogens, but most readily with SA and PA. Further investigation is needed to determine if these findings may in part explain the occasionally refractory nature of post-TT otorrhea associated with SA and PA.
Get full access to this article
View all access options for this article.