Matthias Leonhard

Comparison of biofilm formation on new Phonax and Provox 2 voice prostheses—A pilot study

In voice rehabilitation for laryngectomized patients, voice prosthetic biofilm formation is still an unsolved problem. Design and materials of voice prostheses have been altered by manufacturers to improve function and extend the lifetime of devices. The goal of the study was to investigate biofilm formation on Provox 2 and Phonax, recently introduced voice prostheses made of thermoplastic polyurethane.

Anaerobic and microaerophilic pathogens in the biofilm formation on voice prostheses: A pilot study†

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 biofilm of voice prostheses have mainly focused on aerobic bacteria. Anaerobic bacteria as an integral part of the biofilms on voice prostheses have not been investigated yet.

Growth kinetics of candida biofilm on medical polymers: A long‐term in vitro study

Recent in vitro models simulating biofilm formation on medical polymers are restricted to only short‐term observation periods of 2 hours to 12 days.

Pharyngolaryngectomy with free jejunal autograft reconstruction and tracheoesophageal voice restoration: Indications for replacements, microbial colonization, and indwelling times of the Provox 2 voice prostheses

The purpose of this prospective study was to investigate shunt‐related and device‐related complications and microbial colonization of voice prostheses in patients after pharyngolaryngectomy with jejunal autograft reconstruction in comparison to patients after standard laryngectomy.

Antibiofilm activity of carboxymethyl chitosan on the biofilms of non-Candida albicans Candida species

Although most cases of candidiasis have been attributed to Candida albicans, non-C. albicans Candida species have been isolated in increasing numbers in patients. In this study, we determined the inhibition of carboxymethyl chitosan (CM-chitosan) on single and mixed species biofilm of non-albicans Candida species, including Candida tropicalis, Candida parapsilosis, Candida krusei and Candida glabrata. Biofilm by all tested species in microtiter plates were inhibited nearly 70%. CM-chitosan inhibited mixed species biofilm in microtiter plates and also on medical materials surfaces. To investigate the mechanism, the effect of CM-chitosan on cell viability and biofilm growth was employed. CM-chitosan inhibited Candida planktonic growth as well as adhesion. Further biofilm formation was inhibited with CM-chitosan added at 90min, 12h or 24h after biofilm initiation. CM-chitosan was not only able to inhibit the metabolic activity of Candida cells, but was also active upon the establishment and the development of biofilms.

Inhibition of mixed fungal and bacterial biofilms on silicone by carboxymethyl chitosan

Mixed biofilms with fungi and bacteria are the leading cause for the failure of medical silicone devices, such as voice prostheses in laryngectomy. In this study, we determined the effect of carboxymethyl chitosan (CM-chitosan) on mixed biofilm formation of fungi and bacteria on silicone which is widely used for construction of medical devices. Mixed biofilm formations were inhibited 72.87% by CM-chitosan. Furthermore, CM-chitosan significantly decreased the metabolic activity of the biofilms using 2, 3-bis (2-methoxy-4-nitro-5-sulfo-phenyl)-2H-tetrazolium-5 carboxanilide (XTT) reduction assay. The examination using confocal laser scanning microscopy and scanning electron microscope confirmed that CM-chitosan inhibited the mixed biofilm and damaged the cells. Effects of CM-chitosan on different stages of biofilms were also evaluated. CM-chitosan inhibited the adhesion of fungi and bacteria with an efficiency of >90%. It prevented biofilm formation at efficiencies of 69.86%, 50.88% and 46.58% when CM-chitosan was added at 90min, 12h and 24h after biofilm initiation, respectively. Moreover, CM-chitosan inhibited Candida yeast-to-hyphal transition. CM-chitosan was not only able to inhibit the metabolic activity of biofilms, but also active upon the establishment and development of biofilm. Therefore, CM-chitosan may serve as a possible antibiofilm agent to limit biofilm formation on voice prostheses.

The antimicrobial effect of Octenidine-dihydrochloride coated polymer tracheotomy tubes on Staphylococcus aureus and Pseudomonas aeruginosa colonisation

BackgroundThe surface of polymeric tracheotomy tubes is a favourable environment for biofilm formation and therefore represents a potential risk factor for the development of pneumonia after tracheotomy. The aim of this in-vitro study was to develop octenidine-dihydrochloride (OCT) coated polymer tracheotomy tubes and investigate any effects on Staphylococcus (S.) aureus and Pseudomonas (P.) aeruginosa colonization. Additionally the resistance of the OCT coating was tested using reprocessing procedures like brushing, rinsing and disinfection with glutaraldehydeResultsContamination with S. aureus: Before any reprocessing, OCT coated tracheotomy tubes were colonized with 103 cfu/ml and uncoated tracheotomy tubes with 105 cfu/ml (P = 0.045). After reprocessing, no differences in bacterial concentration between modified and conventional tubes were observed.Contamination with P. aeruginosa: Before reprocessing, OCT coated tubes were colonized with 106 cfu/ml and uncoated tubes with 107 cfu/ml (P = 0.006). After reprocessing, no significant differences were observed.ConclusionOCT coating initially inhibits S. aureus and P. aeruginosa colonisation on tracheotomy tubes. This effect, however, vanishes quickly after reprocessing of the tubes due to poor adhesive properties of the antimicrobial compound. Despite the known antimicrobial effect of OCT, its use for antimicrobial coating of tracheotomy tubes is limited unless methods are developed to allow sustained attachment to the tube.

Towards Objective Voice Assessment: The Diplophonia Diagram.

OBJECTIVES Diplophonia is an often misinterpreted symptom of disordered voice, and needs objectification. An audio signal processing algorithm for the detection of diplophonia is proposed. Diplophonia is produced by two distinct oscillators, which yield a profound physiological interpretation. The algorithms performance is compared with the clinical standard parameter degree of subharmonics (DSH). STUDY DESIGN This is a prospective study. METHODS A total of 50 dysphonic subjects with (28 with diplophonia and 22 without diplophonia) and 30 subjects with euphonia were included in the study. From each subject, up to five sustained phonations were recorded during rigid telescopic high-speed video laryngoscopy. A total of 185 phonations were split up into 285 analysis segments of homogeneous voice qualities. In accordance to the clinical group allocation, the considered segmental voice qualities were (1) diplophonic, (2) dysphonic without diplophonia, and (3) euphonic. The Diplophonia Diagram is a scatter plot that relates the one-oscillator synthesis quality (SQ1) to the two-oscillator synthesis quality (SQ2). Multinomial logistic regression is used to distinguish between diplophonic and nondiplophonic segments. RESULTS Diplophonic segments can be well distinguished from nondiplophonic segments in the Diplophonia Diagram because two-oscillator synthesis is more appropriate for imitating diplophonic signals than one-oscillator synthesis. The detection of diplophonia using the Diplophonia Diagram clearly outperforms the DSH by means of positive likelihood ratios (56.8 versus 3.6). CONCLUSIONS The diagnostic accuracy of the newly proposed method for detecting diplophonia is superior to the DSH approach, which should be taken into account for future clinical and scientific work.

Influence of culture conditions for clinically isolated non-albicans Candida biofilm formation

Non-albicans Candida species have been isolated in increasing numbers in patients. Moreover, they are adept at forming biofilms. This study analyzed biofilm formation of clinically isolated non-albicans Candida, including Candida tropicalis, Candida krusei and Candida parapsilosis under the influence of different growth media (RPMI 1640, YPD and BHI) and several culture variables (inoculum concentration, incubation period and feeding conditions). The results showed that culture conditions strongly influenced non-albicans Candida species biofilm formation. YPD and BHI resulted in larger amount of biofilm formation with higher metabolic activity of biofilms. Furthermore, the growth media seems to have varying effects on adhesion and biofilm development. Growth conditions may also influence biofilm formation, which was enhanced when starting the culture with a larger inoculum, longer incubation period and using a fed-batch system. Therefore, the potential influences of external environmental factors should be considered when studying the non-albicans Candida biofilms in vitro.

Summarized institutional experience of paediatric airway surgery

OBJECTIVES The management of paediatric airway stenosis is complex, and requires a dedicated team, consisting of thoracic surgeons, phoniatricians, logopaedics, paediatricians and anaesthetists. The majority of paediatric laryngotracheal stenosis is a sequela of prematurity and prolonged post-partal intubation/tracheostomy. Surgical correction is often difficult due to a frequent combination of glottic and subglottic defects. METHODS In 2012, the Laryngotracheal Program Vienna was launched. Since then, 18 paediatric patients were surgically treated for (laryngo-)tracheal problems. RESULTS The median age of our patients was 26 months (range 2-180 months). Laryngotracheal stenosis extending up to the level of the vocal cords was evident in 9 patients. Three children were diagnosed with an isolated subglottic, and four with a short-segment tracheal stenosis or malacia. Two patients had a long-segment congenital malformation together with vascular ring anomalies. Five children were pretreated by rigid endoscopy before surgical correction, 12 of our 18 patients had a tracheostomy, 3 children were intubated at the time of operation. Different techniques of corrections were applied: laryngotracheal reconstruction (n = 4), extended partial cricotracheal resection (n = 4), cricotracheal resection with or without anterior split or dorsal mucosal flap (n = 4), slide tracheoplasty (n = 2), tracheal resection (n = 4). In 8 patients, a rib cartilage interposition was necessary in order to obtain a sufficient lumen enlargement and in 7 of these patients, an LT-Mold was placed to stabilize the reconstruction. We lost 2 patients, who were referred to our institution after failure of multiple preceding interventions, 2 and 3 months after the operation. Twelve patients are currently in an excellent condition, one is in an acceptable condition without a need for an intervention. Two patients required an endoscopic reintervention 18 and 33 months after the operation, 1 child is currently still cannulated. CONCLUSIONS Paediatric airway surgery is complex, and requires a dedicated interdisciplinary team. An armamentarium of different resection and reconstruction techniques is necessary in order to achieve good long-term results.