Influence of the Provox Flush, blowing and imitated coughing on voice prosthetic biofilms in vitro

In Vitro Antimicrobial Susceptibility Testing of Biofilm-Growing Bacteria: Current and Emerging Methods

The antibiotic susceptibility of bacterial pathogens is typically determined based on planktonic cells, as recommended by several international guidelines. However, most of chronic infections - such as those established in wounds, cystic fibrosis lung, and onto indwelling devices - are associated to the formation of biofilms, communities of clustered bacteria attached onto a surface, abiotic or biotic, and embedded in an extracellular matrix produced by the bacteria and complexed with molecules from the host. Sessile microorganisms show significantly increased tolerance/resistance to antibiotics compared with planktonic counterparts. Consequently, antibiotic concentrations used in standard antimicrobial susceptibility tests, although effective against planktonic bacteria in vitro, are not predictive of the concentrations required to eradicate biofilm-related infections, thus leading to treatment failure, chronicization and removal of material in patients with indwelling medical devices.Meeting the need for the in vitro evaluation of biofilm susceptibility to antibiotics, here we reviewed several methods proposed in literature highlighting their advantages and limitations to guide scientists towards an appropriate choice.

Factors influencing clinical consistency and variability in voice prosthesis management

PURPOSE

Anecdotally it is recognised that management of tracheoesophageal speech (TES) post-laryngectomy varies between speech language pathology (SLP) services and clinicians. This study reviewed patterns of practice for TES management to examine patterns of practice and explore factors influencing variability.

METHOD

A national survey was completed by SLP's from clinical services which manage TES. This online survey examined demographic and caseload information, initial voice prosthesis (VP) placement and procedures, VP cleaning and care recommendations, humidification management, equipment and service provision, and service delivery options at each site.

RESULT

Lead clinicians from 34 sites (85% response rate) responded. Most clinical practice regarding initial VP insertion and management, as well as the timing and delivery of voice rehabilitation was highly consistent. Patient use of antifungal medications, TES and associated equipment provision, humidification management immediately post-surgery and some aspects of initial VP insertion were variable between services. The nature of the clinical setting, equipment funding and level of research evidence influenced variability in practice.

CONCLUSION

Variability exists in a number of aspects of practice across Australian services offering TES management. Sources of variability need to be addressed nationally to ensure there is consistent, quality care available for all patients.

Biofilm in voice prosthesis: A prospective cohort study and laboratory tests using sonication and SEM analysis

OBJECTIVE

The objective of the study was to compare the biofilm growing pattern and its morphological extent on silicone and a teflon-like material using a sonication process and a Scanning Electron Microscope (SEM).

DESIGN

A prospective cohort study and a laboratory study.

SETTING

Otolaryngology -Head and Neck surgery Department and the Microbiology Institute.

PARTICIPANTS

The participants included fifteen laryngectomised patients with phonatory prostheses, which were removed because of device failure, and two different kinds of phonatory prostheses from the laboratory (Provox 2 and ActiValve) that were artificially colonised by Candida albicans.

MAIN OUTCOME MEASURES

Tracheo-oesophageal puncture (TEP) is currently considered the gold standard for post-laryngectomy voice rehabilitation. "Leakage" represents the most common cause of substitution and is generated by biofilm colonisation of the prosthesis by mixed mycotic and bacterial agents. New biomaterials have been developed that are deemed to be more resistant to the colonisation of micro-organisms and material deformation.

RESULTS

The devices showed colonisation by mixed bacterial flora (Staphylococci 13%, Streptococci 9%, and Haemophilus influenzae 5%) and by yeasts (Candida albicans 12%). Moreover, we observed a different distribution of biofilm layers in Provox ActiValve (22.56%) compared to Provox 2 (56.82%) after experimental colonisation by the previously isolated Candida strain.

CONCLUSION

Resident microbiological species from the upper airways unavoidably colonise the polymer surfaces, and no strategies have been effective except for the manipulation of the chemical-physical properties of the device's polymer. Our study confirms that Provox ActiValve, which is made with a fluoroplastic material (teflon-like), is less subject to in vitro colonisation by Candida, and thus showed a higher clinical resistance to biofilm and a longer lifespan. The sonication seems to significantly improve the knowledge of bacterial and mycotic flora in biofilm colonisation. The design of a device for the daily cleaning capable to reach and brush the oesophageal flange of the prosthesis preserving the valve mechanism could represent a practical and simple help in this still unsolved problem.

Vibratory stimulus reduces in vitro biofilm formation on tracheoesophageal voice prostheses

OBJECTIVES/HYPOTHESIS

Demonstrate that biofilm formation will be reduced on tracheoesophageal prostheses when vibratory stimulus is applied, compared to controls receiving no vibratory stimulus, in a dynamic in vitro model of biofilm accumulation simulating the interface across the tracheoesophageal puncture site.

STUDY DESIGN

Prospective, randomized, controlled, crossover in university laboratory.

METHODS

Ex vivo tracheoesophageal prostheses were obtained from university-affiliated speech language pathologists at Indiana University School of Medicine, Indianapolis. Prostheses demonstrating physical integrity and an absence of gross biofilm accumulation were utilized. Sixteen prostheses were cleansed and sterilized prior to random placement by length in two modified Robbins devices arranged in parallel. Each device was seeded with a polymicrobial oral flora on day 1 and received basal artificial salivary flow continuously with three growth medium meals daily. One device was randomly selected for vibratory stimulus, and 2 minutes of vibration was applied to each prosthesis before and after meals for 5 days. The prostheses were explanted and sonicated, and the biofilm cultured for enumeration. This process was repeated after study arm crossover.

RESULTS

Tracheoesophageal prostheses in the dynamic model receiving vibratory stimulus demonstrated reduced gross biofilm accumulation and a significant biofilm colony forming unit per milliliter reduction of 5.56-fold compared to nonvibratory controls (P < 0.001). Significant reductions were observed within length subgroups.

CONCLUSION

Application of vibratory stimulus around meal times significantly reduces biofilm accumulation on tracheoesophageal prostheses in a dynamic in vitro model. Further research using this vibratory stimulus method in vivo will be required to determine if reduced biofilm accumulation correlates with longer device lifespan.

LEVEL OF EVIDENCE

NA Laryngoscope, 126:2752-2757, 2016.

Device life of the Provox Vega voice prosthesis

Device life of the Provox Vega Indwelling voice prosthesis is as yet untested outside Europe. The current study examined device life and reasons for replacement within an Australian clinical setting. Twenty-three participants were monitored for device life and reasons for replacement. Main outcome measure was days to failure of initial device. Average device life and reasons for replacement were secondary measures. Initial device life data revealed 67 % had functioning devices at 3 months, 52 % at 6 months and 29 % at 12 months. Average device life was 207 days (median of 222). The majority of devices (97 %) failed due to leakage through the prosthesis. The Provox Vega Indwelling voice prosthesis had favourable device life in this cohort of patients and in comparison to European data. Reasons for replacement were consistent with international literature.

Tracheostomy cannulas and voice prosthesis

Cannulas and voice prostheses are mechanical aids for patients who had to undergo tracheotomy or laryngectomy for different reasons. For better understanding of the function of those artificial devices, first the indications and particularities of the previous surgical intervention are described in the context of this review. Despite the established procedure of percutaneous dilatation tracheotomy e.g. in intensive care units, the application of epithelised tracheostomas has its own position, especially when airway obstruction is persistent (e.g. caused by traumata, inflammations, or tumors) and a longer artificial ventilation or special care of the patient are required. In order to keep the airways open after tracheotomy, tracheostomy cannulas of different materials with different functions are available. For each patient the most appropriate type of cannula must be found. Voice prostheses are meanwhile the device of choice for rapid and efficient voice rehabilitation after laryngectomy. Individual sizes and materials allow adaptation of the voice prostheses to the individual anatomical situation of the patients. The combined application of voice prostheses with HME (Head and Moisture Exchanger) allows a good vocal as well as pulmonary rehabilitation. Precondition for efficient voice prosthesis is the observation of certain surgical principles during laryngectomy. The duration of the prosthesis mainly depends on material properties and biofilms, mostly consisting of funguses and bacteries. The quality of voice with valve prosthesis is clearly superior to esophagus prosthesis or electro-laryngeal voice. Whenever possible, tracheostoma valves for free-hand speech should be applied. Physicians taking care of patients with speech prostheses after laryngectomy should know exactly what to do in case the device fails or gets lost.

Eradicating chronic ear, nose, and throat infections: a systematically conducted literature review of advances in biofilm treatment

OBJECTIVE

Bacteria can grow as individual, planktonic organisms or as complex biofilm communities that are more resistant to treatment. This review was designed to systematically search to identify recent laboratory studies on eradication of biofilms in otolaryngologic infections to highlight promising advances in biofilm treatment.

DATA SOURCES

A systematic electronic literature search of Medline/PubMed, CINHAL, and Web of Science was conducted for articles describing the treatment of biofilm infections in ear, nose, and throat (ENT) diseases through March 2010. English-language articles and articles with an English abstract that focused on biofilm treatment were considered for review.

REVIEW METHODS

Each included article was reviewed by one of the authors for study design, treatment intervention, and outcome. Data from in vitro and animal studies were considered separately from human studies.

RESULTS

A total of 30 articles were identified for this review, including 5 studies that included a human treatment component. In general, antibiotics were relatively ineffective for eradicating biofilm infections. Markedly higher antibiotic dosages were required to reduce biofilm presence compared with doses that were effective in eradicating planktonic bacteria. Mupirocin irrigation, gentian violet, and thiamphenicol glycinate acetylcysteine effectively eradicated biofilms. Physical disruption, surfactants, and probiotics were also shown to be beneficial in both nonhuman and human studies.

CONCLUSION

Eradicating ENT biofilms is difficult when treating single-organism or mixed flora biofilms. Antibiotic therapy is often ineffective against biofilms, and clinical treatment may need to focus on nonantibiotic therapies that reduce, disrupt, or eradicate ENT biofilms.

Microbial colonization of tracheoesophageal voice prostheses (Provox2) following total laryngectomy

The purpose of this study was to determine the presence of individual microorganisms and the most frequent microbial combinations in the biofilm of the indwelling Provox2 voice prosthesis in situ. Furthermore, we wanted to evaluate the possible influence of biofilm composition on the mean and median lifetime of these voice prostheses. Over a 5-year period, implantation of a Provox2 voice prosthesis was performed in 85 patients, or 90% of the overall number of patients who underwent total laryngectomy. In total 100 implanted voice prostheses, at least one of every patient, were microbiologically processed immediately after being replaced. Out of the total of 292 isolates, 67% were bacteria and the remaining 33% were yeasts. The most frequently found yeast species on voice prostheses biofilms was C. albicans, followed by C. krusei and C. tropicalis. The most frequently isolated bacteria included Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Proteus mirabilis, and Streptococcus agalactiae. Simultaneous presence of bacteria and fungi was established in 83% of the processed voice prostheses; in 16% of samples the biofilm contained only one or more bacterial species. The mean time of implantation was 238 days and the median lifetime of the device was 180 days. Dividing the prostheses in four groups according to the composition of biofilm revealed that the device lifetimes varied significantly between groups. The longest lifetime of voice prostheses was associated with the presence of single fungal isolate in combination with bacteria. There is a significant correlation between biofilm composition and the device life time.