Anaerobic and microaerophilic bacteria in the biofilm on voice prostheses

Voice rehabilitation with voice prostheses is a standard therapy in laryngectomized patients. Biofilm formation on the surface of the voice prostheses causes device failure and requires frequent replacements. Studies analyzing the biofilmof voice prostheses have mainly focused on fungi and aerobic bacteria. Anaerobic bacteria as an integral part of the biofilms on voice prostheses have not been investigated yet.

Betl et al of the Department of Periodontology, Bernhard Gottlieb School of Dentistry, Vienna, Austria,  performed aprospective pilot study on the occurrence of anaerobic and microaerophilic pathogens in biofilm formation on voice prostheses.

Biofilmsamples of 15 voice prostheses were analyzed using a polymerase chain reaction-based hybridization method, searching for the existence of 11 selected anaerobic and microaerophilic pathogens.

In 80% of the voice prostheses, at least one and up to 10 of the tested bacteria were identified. Fusobacterium nucleatumwas the most common isolate (73%). Other frequently occurring pathogens were Treponema denticola (40%), Tannerella forsythia (33%), and Eikenella corrodens (33%). There was no correlation between the number of identified bacteria and the indwelling times (mean, 127 days; maximum, 344 days; minimum, 22 days).

This is the first study showing the presence of anaerobic and microaerophilic potential pathogens as part of the biofilmformation on the surface of voice prostheses. Further studies are warranted to find out if these organisms may be responsible for accelerated biofilm formation and reduced lifetime of the voice prostheses.

Anaerobic biofilm

Laryngectomy is performed more often in patients with advanced laryngeal cancer

Zhu and colleagues recently investigated whether having a medical comorbidity influenced the choice of treatment of patients with advanced squamous cell carcinoma of the larynx. Comorbidity is the presence of an underlying pathologic condition that has an impact on a patient's total burden of disease. More than 2/3 of patients with cancer have a comorbid condition, and up to one-third of these patients have 2 or more, with hypertension, cardiovascular disease, and pulmonary disease among the most prevalent.

The study evaluated 16 849 patients from more than 1400 medical centers diagnosed with primary invasive advanced squamous cell carcinoma of the larynx between 2003 and 2008. They were selected from the National Cancer Database.

The study demonstrated that receipt of treatment (chemoradiation vs total laryngectomy) was significantly associated with comorbidity. Patients with comorbidity were more likely to have subtotal or total laryngectomy. Patients were also more likely to undergo laryngectomy if they had stage IV disease and if they had been diagnosed at a teaching or research institution. Patients were more likely to receive chemoradiation if they were diagnosed after 2003 or if they lived in a zip code with a high percentage of high school graduates.

The study is the first that demonstrates that patients with advanced laryngeal cancer with one or more comorbidities are more likely to receive surgery than chemoradiation compared with patients without any comorbidity. Previous studies have demonstrated better survival in patients with advanced laryngeal cancer who had been treated with surgery compared with those without.

This study supports the superiority of laryngectomy even in presence of comorbidity.  Even though patients with a comorbidity were less healthy initially their outcome was better after laryngectomy than those who received chemoradiation.