Richard George Douglas

Although nasal breathing is the preferred pathway for quiet respiration, up to 30% of the population are habitual mouth breathers. This systematic review investigates the association between mouth breathing and musculoskeletal outcomes. A literature search was conducted on Medline, Embase, CINAHL, Web of Science, and Scopus from inception to August 8, 2025. Eligible studies included adults and investigated the association between chronic or induced mouth breathing (or relevant proxies such as nasal obstruction or induced nasal obstruction) and outcomes of musculoskeletal pain, temporomandibular joint dysfunction (TMD), changes in posture or muscle activity/electromyography (EMG). Outcome data were summarized using a narrative synthesis due to heterogeneity in included studies. GRADE was used to assess evidence certainty. Studies evaluated the impact of chronic mouth breathing (n = 4) or induced mouth breathing (n = 8) on posture, TMD, masticatory muscle activity, and efficiency. No study evaluated the direct relationship between chronic or induced mouth breathing and pain. Compared to nasal breathers, mouth breathers had a higher prevalence of TMD, adopted a head forward posture and increased lumbar lordosis, demonstrated reduced chewing efficiency, and had reduced masseter and temporalis, and increased suprahyoid EMG activity. Certainty of evidence was very low. This review found very low certainty evidence that chronic or induced mouth breathing may negatively impact posture, temporomandibular joint function, masticatory muscle activity, and efficiency. However, there is no data on whether there is an impact on pain. Due to the very low certainty of evidence, caution is recommended when interpreting the current literature. N/A.

Introduction. Biofilms have been implicated as a potential cause of chronic rhinosinusitis (CRS), with patients showing an increased prevalence of biofilms, likely contributing to antibiotic ineffectiveness in these individuals. In many environments, biofilms are polymicrobial, with interspecies interactions promoting bacterial survival and encouraging robust growth. Improvements in visualization techniques for biofilms have enabled species-specific identification, leading to a growing body of literature using these techniques and examining severity in different phenotypes of CRS. Gap Statement. It is unclear whether sinus biofilms are typically poly- or monomicrobial, and if they are correlated with clinical severity in CRS. Aim. We conducted a scoping review to determine how prevalent biofilms were in sinus tissue of patients with CRS. Furthermore, we correlated disease severity with the presence of biofilms. Methodology. We searched PubMed, Scopus, Medline and Web of Science databases for all studies which directly visualized biofilms on tissue from patients with CRS. After screening 1,853 search results, 39 studies were included for analysis in this review. Results. Patients with CRS had a higher prevalence of biofilms compared with controls. We found no significant difference in the proportion of biofilms detected across visualization techniques or based on CRS phenotyping. Fifteen studies reported disease severity by biofilm status; most reported greater severity in patients with biofilms, although only some were statistically significant. Nine studies used techniques capable of detecting polymicrobial biofilms, all of which found a subset of polymicrobial biofilms. Conclusion. Our findings demonstrate an increased prevalence of biofilms in patients with CRS, which may correspond to increased disease severity. The evidence for biofilms being polymicrobial is compelling, although it is based on a small number of studies.

Zoono GermFree24 is a quaternary ammonium compound-based hand sanitiser. Its efficacy against planktonic bacteria is well established, but efficacy against biofilms has not been tested. We investigated the antibiofilm efficacy of Zoono GermFree24 hand sanitiser and a modified formulation against biofilms of Staphylococcus aureus ATCC 6538 and Pseudomonas aeruginosa ATCC 27853 grown in vitro using the Centers for Disease Control (CDC) biofilm reactor and 96-pin lids. Biofilms were immersed in Zoono GermFree24 or Zoono B22-1402A (modified formulation) for 5 min, 1 h, 6 h or overnight (22 ± 2 h). The antiseptic was neutralised and the bacteria remaining after treatment were cultured and quantified. Zoono GermFree24 and Zoono B22-1402A caused time-dependent reductions in viable biofilms of both species with both methods of culture and testing, with more rapid biofilm eradication observed for Zoono B22-1402A. Biofilms grown on 96-pin lids were more quickly eradicated than those grown in the CDC biofilm reactor.

Chronic suppurative otitis media (CSOM) is a chronic middle ear inflammatory condition due to persistent polymicrobial middle ear infection. The interaction between local immune responses and microbial communities is not well understood, complicating the development of targeted therapies. This study aimed to characterise local immune cell responses and microbial composition in CSOM-affected middle ear mucosa, focusing on Pseudomonas aeruginosa and Staphylococcus aureus. A total of 24 CSOM patients and 22 controls undergoing tympanomastoid surgery participated in this prospective study. Middle ear and mastoid mucosa were collected for histological and microbiological analysis. Bacterial identification was performed using standard culture methods and Vitek MS, while immune cell populations were quantified via immunohistochemistry. Statistical analyses were performed using Kruskal–Wallis and Mann–Whitney tests. Microbiology results identified multiple pathogens in CSOM, including S. aureus and P. aeruginosa, with polymicrobial infections in 10 samples. CSOM patients exhibited significantly elevated immune cells, including CD3⁺, CD20⁺, and CD68⁺ cells, compared to controls. Histological analysis showed Gram-positive bacteria in three mastoid samples, with positive antibody staining for S. aureus (20.8%) and P. aeruginosa (12.5%) in CSOM patients. Controls had no bacterial staining. Intracellular bacteria may evade host defences and reduce antibiotic efficacy, contributing to CSOM persistence. Targeting intracellular pathogens in future treatments, along with studying polymicrobial communities, could improve management strategies.

Objectives: Nasal anaesthetic‐decongestant sprays are commonly used prior to nasal instrumentation, such as flexible and rigid nasal endoscopy. Co‐phenylcaine (lignocaine 5%, phenylephrine 0.5%, ENT Technologies Pty Ltd., Melbourne, VIC, Australia) is a combination spray commonly used for this purpose. However, lignocaine is less potent than other local anaesthetics, and both active constituents of Co‐phenylcaine have a bitter taste. It was hypothesised that a combination spray containing tetracaine and oxymetazoline would both offer more potent topical anaesthesia and have a better taste.Methods: Four anaesthetic‐decongestant nasal sprays were tested in 10 healthy participants (Co‐phenylcaine, and tetracaine 0.5%, 1% and 2% with oxymetazoline 0.05%). Sensory thresholds were sequentially measured at the head of the inferior turbinate using Semmes‐Weinstein monofilaments over the following hour. Participants also rated taste on a Likert‐style scale, and reported whether they experienced subjective numbness of the maxillary teeth.Results: A median peak sensory threshold of 60 g (the maximum tested) was observed with Co‐phenylcaine, but this threshold was exceeded by all the tetracaine‐based sprays. Tetracaine 2% with oxymetazoline 0.05% had a significantly more rapid onset than Co‐phenylcaine (4 min vs. 6 min, p < 0.05) and a longer duration of action. Eight participants reported dental numbness after administration of tetracaine 2% with oxymetazoline 0.05%, but only one participant after Co‐phenylcaine. Tetracaine‐based sprays were generally perceived to taste less unpleasant than Co‐phenylcaine. Conclusion: Tetracaine 2% with oxymetazoline 0.05% is a more potent and rapidly acting anaesthetic‐decongestant spray than Co‐phenylcaine, with a longer duration of action.

Objective: Endoscopic sinus and skull base surgery has led to significant improvements in patient outcomes, yet may have come at a cost to surgeons' musculoskeletal (MSK) health. We aimed to determine the prevalence and characteristics of work‐related MSK disorders (WRMDs) in endoscopic sinus and skull base surgeons; to investigate contributing factors for WRMD in this population; and to evaluate the effectiveness of ergonomic interventions on the severity or prevalence of WRMD in this population.Data Sources: Medline, Embase, CINAHL, Web of Science, and Scopus from inception to April 2, 2024. A bibliographic examination was performed for further papers.Review Methods: Inclusion criteria included original peer‐reviewed papers with work‐related MSK outcomes (prevalence, contributing factors, and interventions) relating to endoscopic sinus and/or skull base surgeons in any language.Results: Of 25,772 unique citations, 37 studies met the inclusion criteria. The pooled lifetime, point, and 12‐month prevalences of WRMD were 75.9% (95% confidence interval; I², 67.2%‐83.6%, I² 95.6%), 80.8% (77.0%‐84.3%, I² 98.0%), and 82.0% (71.8%‐90.3%, I² 60.96%) respectively. The neck, lumbar spine, and thoracic spine were the most commonly involved areas. One of 9 studies on contributing factors investigated discomfort as an outcome. The remainder focussed on surrogate outcomes (eg, posture, hand dysfunction). Two of the 13 intervention studies investigated pain or fatigue as an outcome. The remainder targeted posture, muscle activity, or workload.Conclusion: WRMDs are highly prevalent in endoscopic sinus and skull base surgeons. Further studies focusing on the direct outcomes of WRMD such as pain are needed.

Polymyxin B and ethylenediaminetetraacetic acid are antimicrobials possessing antibiofilm activity. They act by displacement and chelation, respectively, of divalent cations in bacterial membranes and may therefore act synergistically when applied in combination. If so, this combination of agents may be useful for the treatment of diseases like cystic fibrosis (CF), in which biofilms are present on the respiratory epithelium. We used checkerboard assays to investigate the synergy between these agents using reference strains Pseudomonas aeruginosa ATCC 27853 and Staphylococcus aureus ATCC 6538 in planktonic form. We then determined the efficacy of each agent against biofilms of both species grown on 96-pin lids and proceeded to combination testing against the P. aeruginosa reference strain and 10 clinical isolates from patients with CF. Synergism was observed for planktonic forms of both species and for biofilms of P. aeruginosa . The susceptibility of biofilms of P. aeruginosa clinical isolates to these agents was variable compared to the laboratory reference strain. This combination of agents may be useful in the management of biofilm-associated conditions, particularly those amenable to topical therapies. These results provide a basis upon which the antimicrobial and antibiofilm efficacy of preparations containing these agents may be enhanced. IMPORTANCE: Bacteria living in biofilms produce a protective matrix which makes them difficult to kill. Patients with severe respiratory disease often have biofilms. Polymyxin B is an antibiotic commonly used in topical medications, such as eye drops and nasal sprays. Ethylenediaminetetraacetic acid (EDTA) is used widely as a preservative in medication but also has antimicrobial properties. It has been hypothesized that Polymyxin B and EDTA could have a synergistic relationship: when used in combination their antimicrobial effect is enhanced. Here, we evaluated the levels at which Polymyxin B and EDTA work together to kill common pathogens Pseudomonas aeruginosa and Staphylococcus aureus . We found that Polymyxin B and EDTA were synergistic. This synergy may be useful in the management of planktonic infection with P. aeruginosa and S. aureus , or biofilm infection with P. aeruginosa . This synergy may be beneficial in the treatment of respiratory biofilms, in which P. aeruginosa biofilms are common.

Objectives: Bacterial biofilms on the sinonasal mucosa, especially biofilms of Staphylococcus aureus, are associated with greater severity and recalcitrance of chronic rhinosinusitis (CRS). There are few, if any, antibiofilm agents suitable for sinonasal application available for the management of this problem. Nasodine® Nasal Spray (Nasodine) is a 0.5% povidone‐iodine‐based formulation that has been developed for sinonasal application. We investigated the antibiofilm efficacy of Nasodine to determine whether it may be a candidate for the treatment of biofilm‐associated CRS.Methods: Biofilms of S. aureus ATCC 6538 were grown in vitro using the Centers for Disease Control biofilm reactor. Intact biofilms were treated by immersion in 0.9% saline (control), half concentration Nasodine, or full concentration Nasodine for between 5 min and 6 h. Further biofilm cells were dispersed into suspension then treated for between 30 s and 5 min. Surviving bacteria were then enumerated by culture and counting colonies, and the log₁₀ reduction in viable bacteria was compared with control.Results: Nasodine demonstrated time and concentration‐dependent bacterial killing against intact biofilm. Statistically significant reductions in viable bacteria from intact biofilms were seen with exposures as brief as 5 min. Nasodine consistently eradicated dispersed biofilm within 1 min.Conclusion: Nasodine is highly active against biofilms of S. aureus ATCC 6538 in vitro. Biofilm killing is impeded by the presence of the intact biofilm structure.Lay summary:In chronic rhinosinusitis (CRS), bacterial communities called biofilms are associated with more severe inflammation. An iodine‐based nasal spray called Nasodine almost completely eradicates bacterial biofilms after 6 h of exposure. Nasodine may be useful for treating CRS. Laryngoscope, 133:2490–2495, 2023