Alloiococcus otitidis Forms Multispecies Biofilm with Haemophilus influenzae: Effects on Antibiotic Susceptibility and Growth in Adverse Conditions.

Otitis media with effusion (OME) is a biofilm driven disease and commonly accepted otopathogens, such as Haemophilus influenzae, Streptococcus pneumonia, and Moraxella catarrhalis, have been demonstrated to form polymicrobial biofilms within the middle ear cleft. However, Alloiococcus otitidis (A. otitidis), which is one of the most commonly found bacteria within middle ear aspirates of children with OME, has not been described to form biofilms. The aim of this study was to investigate whether A. otitidis can form biofilms and investigate the impact on antibiotic susceptibility and survivability in polymicrobial biofilms with H. influenzae in vitro. The ability of A. otitidis to form single-species and polymicrobial biofilms with H. influenzae was explored. Clinical and commercial strains of A. otitidis and H. influenzae were incubated in brain heart infusion with and without supplementation. Biofilm was imaged using confocal laser scanning microscopy and scanning electron microscopy. Quantification of biofilm biomass and viable bacterial number was assessed using crystal violet assays and viable cell counting in both optimal growth conditions and in adverse growth conditions (depleted media and sub-optimal growth temperature). Antimicrobial susceptibility and changes in antibiotic resistance of single-species and multi-species co-culture were assessed using a microdilution method to assess minimal bactericidal concentration and E-test for amoxicillin and ciprofloxacin. A. otitidis formed single-species and polymicrobial biofilms with H. influenzae. Additionally, whilst strain dependent, combinations of polymicrobial biofilms decreased antimicrobial susceptibility, albeit a small magnitude, in both planktonic and polymicrobial biofilms. Moreover, A. otitidis promoted H. influenzae survival by increasing biofilm production in depleted media and at suboptimal growth temperature. Our findings suggest that A. otitidis may play an indirect pathogenic role in otitis media by altering H. influenzae antibiotic susceptibility and enhancing growth under adverse conditions.

A randomized controlled trial of a middle meatal silastic stent for reducing adhesions and middle turbinate lateralization following endoscopic sinus surgery.

BACKGROUND: Endoscopic sinus surgery (ESS) is indicated for patients with recalcitrant chronic rhinosinusitis symptoms. However, surgical revision can be required because of adhesion formation and middle turbinate lateralization. We investigate the efficacy of a middle meatal silastic stent in reducing these complications after ESS. METHODS: Thirty-six patients were randomized to receive a silastic stent in the middle meatus unilaterally after ESS. The surgeon was blinded to the side receiving the stent until completion of the ESS. The contralateral side, with no stent, was the control side. Patients completed a 7-day, postoperative, visual analog scale symptom diary and were blinded to the stent side until its removal at the first postoperative visit. Patients were followed up after 2, 8, and 24 weeks. Endoscopic video of the sinus cavities were recorded at all visits and 2 blinded, independent ear/nose/throat (ENT) surgeons assessed the videos using a modified Lund-Kennedy scoring system. RESULTS: Thirty-five of 36 patients completed 6-months' follow-up. Middle turbinate lateralization was observed in 13 sides without a stent vs 1 side with a stent. There was a significant reduction in adhesions at weeks 2 and 8 (p < 0.001) and crusting (p < 0.01) in the stent side compared to control. Video scores at 6 months after surgery for stent and control sides remained unchanged from the 8-week visit. There was no difference between sides for symptom scores, edema, or nasal discharge. CONCLUSION: Middle meatal silastic stents are well tolerated by patients and effective in reducing middle turbinate lateralization, adhesions, and crusting postoperatively in ESS.