Nasal carriage of Staphylococcus aureus, including community-associated methicillin-resistant strains, in Queensland adults

Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) infections are emerging in southeast Queensland, Australia, but the incidence of carriage of CA-MRSA strains is unknown. The aim of this study was to assess the nasal carriage rate of S. aureus, including CA-MRSA strains, in the general adult population of southeast Queensland. 396 patients presenting to general practices in two Brisbane suburbs and 303 volunteers randomly selected from the electoral rolls in the same suburbs completed a medical questionnaire and had nasal swabs performed for S. aureus. All isolates of S. aureus underwent antibiotic susceptibility testing and single-nucleotide polymorphism (SNP) and binary typing, including determination of Panton–Valentine leukocidin (PVL). The nasal carriage rate of methicillin-susceptible S. aureus (MSSA) was 202/699 (28%), a rate similar to that found in other community-based nasal carriage studies. According to multivariate analysis, nasal carriage of S. aureus was associated with male sex, young adult age group and Caucasian ethnicity. Only two study isolates (one MSSA and one CA-MRSA) carried PVL. The nasal carriage rate of MRSA was low, at 5/699 (0.7%), and only two study participants (0.3%) had CA-MRSA strains. CA-MRSA is an emerging cause of infection in southeast Queensland, but as yet the incidence of carriage of CA-MRSA in the general community is low.

Oxygen delivery through high-flow nasal cannulae increase end-expiratory lung volume and reduce respiratory rate in post-cardiac surgical patients

Background: High-flow nasal cannulae (HFNC) create positive oropharyngeal airway pressure but it is unclear how their use affects lung volume. Electrical impedance tomography (EIT) allows assessment of changes in lung volume by measuring changes in lung impedance. Primary objectives were to investigate the effects of HFNC on airway pressure (Paw) and end-expiratory lung volume (EELV), and to identify any correlation between the two. Secondary objectives were to investigate the effects of HFNC on respiratory rate (RR), dyspnoea, tidal volume and oxygenation; and the interaction between body mass index (BMI) and EELV. Methods: Twenty patients prescribed HFNC post-cardiac surgery were investigated. Impedance measures, Paw, PaO2/FiO2 ratio, RR and modified Borg scores were recorded first on low flow oxygen (nasal cannula or Hudson face mask) and then on HFNC. Results: A strong and significant correlation existed between Paw and end-expiratory lung impedance (EELI) (r=0.7, p<0.001). Compared with low flow oxygen, HFNC significantly increased EELI by 25.6% (95% CI 24.3, 26.9) and Paw by 3.0 cmH2O (95% CI 2.4, 3.7). RR reduced by 3.4 breaths per minute (95% CI 1.7, 5.2) with HFNC use, tidal impedance variation increased by 10.5% (95% CI 6.1, 18.3) and PaO2/FiO2 ratio improved by 30.6 mmHg (95% CI 17.9, 43.3). HFNC improved subjective dyspnoea scoring (p=0.023). Increases in EELI were significantly influenced by BMI, with larger increases associated with higher BMIs (p<0.001). Conclusions: This study suggests that HFNC improve dyspnoea and oxygenation by increasing both EELV and tidal volume, and are most beneficial in patients with higher BMIs.

Comparative study of coagulase negative Staphylococci (CoNS) from clinical isolates, skin and nasal sources

Staphylococci are important pathogenic bacteria responsible for a range of diseases in humans. The most frequently isolated microorganisms in a hospital microbiology laboratory are staphylococci. The general classification of staphylococci divides them into two major groups; Coagulase-positive staphylococci (e.g. Staphylococcus aureus) and Coagulase-negative staphylococci (e.g. Staphylococcus epidermidis). Coagulase-negative staphylococcal (CoNS) isolates include a variety of species and many different strains but are often dominated by the most important organism of this group, S. epidermidis. Currently, these organisms are regarded as important pathogenic organisms causing infections related to prosthetic materials and surgical wounds. A significant number of S. epidermidis isolates are also resistant to different antimicrobial agents. Virulence factors in CoNS are not very clearly established and not well documented. S. epidermidis is evolving as a resistant and powerful microbe related to nosocomial infections because it has different properties which independently, and in combination, make it a successful infectious agent, especially in the hospital environment. Such characteristics include biofilm formation, drug resistance and the evolution of genetic variables. The purpose of this project was to develop a novel SNP genotyping method to genotype S. epidermidis strains originating from hospital patients and healthy individuals. High-Resolution Melt Analysis was used to assign binary typing profiles to both clinical and commensal strains using a new bioinformatics approach. The presence of antibiotic resistance genes and biofilm coding genes were also interrogated in these isolates.

Mailed versus frozen transport of nasal swabs for surveillance of respiratory bacteria in remote Indigenous communities in Australia

Background Surveillance programs and research for acute respiratory infections in remote Australian communities are complicated by difficulties in the storage and transport of frozen samples to urban laboratories for testing. This study assessed the sensitivity of a simple method for transporting nasal swabs from a remote setting for bacterial polymerase chain reaction (PCR) testing. Methods We sampled every individual who presented to a remote community clinic over a three week period in August at a time of low influenza and no respiratory syncytial virus activity. Two anterior nasal swabs were collected from each participant. The left nare specimen was mailed to the laboratory via routine postal services. The right nare specimen was transported frozen. Testing for six bacterial species was undertaken using real-time PCR. Results One hundred and forty participants were enrolled who contributed 150 study visits and paired specimens for testing. Respiratory illnesses accounted for 10% of the reasons for presentation. Bacteria were identified in 117 (78%) presentations for 110 (79.4%) individuals; Streptococcus pneumoniae and Haemophilus influenzae were the most common (each identified in 58% of episodes). The overall sensitivity for any bacterium detected in mailed specimens was 82.2% (95% CI 73.6, 88.1) compared to 94.8% (95% CI 89.4, 98.1) for frozen specimens. The sensitivity of the two methods varied by species identified. Conclusion The mailing of unfrozen nasal specimens from remote communities appears to influence the utility of the specimen for bacterial studies, with a loss in sensitivity for the detection of any species overall. Further studies are needed to confirm our finding and to investigate the possible mechanisms of effect. Clinical trial registration Australia and New Zealand Clinical Trials Registry Number: ACTRN12609001006235. Keywords: Respiratory bacteria; RT-PCR; Specimen transport; Laboratory methods

Creation of protein loaded biodegradable microparticles via ultrasonic atomization suitable for nasal delivery

Improved biopharmaceutical delivery may be achieved via the use of biodegradable microspheres as delivery vehicles. Biodegradable microspheres offer the advantages of maintaining sustained protein release over time whilst simultaneously protecting the biopharmaceutical from degradation. Particle samples produced by ultrasonic atomization were studied in order to determine a feed stock capable of producing protein loaded poly-ε-caprolactone (PCL) particles suitable for nasal delivery (i.e., less than 20 μm). A 40 kHz atomization system was used with a 6 mm full wave atomization probe. The effect of solids percent, feed flow rate, volumetric ratio of the polymer stock to the protein stock, and protein concentration in the protein stock on particle size characteristics were determined. It was shown that feed stocks containing 100 parts of 0.5 or 1.0% w/v PCL in acetone with one part 100 mg ml -1 BSA and 15 mg ml -1 PVA produced particles with a mass moment diameter (D[4,3]) of 13.17 μm and 9.10 μm, respectively in addition to displaying high protein encapsulation efficiencies of 93 and 95%, respectively. The biodegradable PCL particles were shown to be able to deliver encapsulated protein in vitro under physiological conditions.

Enhanced chondrogenesis of human nasal septum derived progenitors on nanofibrous scaffolds

Topographical cues can be exploited to regulate stem cell attachment, proliferation, differentiation and function in vitro and in vivo. In this study, we aimed to investigate the influence of different nanofibrous topographies on the chondrogenic differentiation potential of nasal septum derived progenitors (NSP) in vitro. Aligned and randomly oriented Ploy (L-lactide) (PLLA)/Polycaprolactone (PCL) hybrid scaffolds were fabricated via electrospinning. First, scaffolds were fully characterized, and then NSP were seeded on them to study their capacity to support stem cell attachment, proliferation and chondrogenic differentiation. Compared to randomly oriented nanofibers, aligned scaffolds showed a high degree of nanofiber alignment with much better tensile strength properties. Both scaffolds supported NSP adhesion, proliferation and chondrogenic differentiation. Despite the higher rate of cell proliferation on random scaffolds, a better chondrogenic differentiation was observed on aligned nanofibers as deduced from higher expression of chondrogenic markers such as collagen type II and aggrecan on aligned scaffolds. These findings demonstrate that electrospun constructs maintain NSP proliferation and differentiation, and that the aligned nanofibrous scaffolds can significantly enhance chondrogenic differentiation of nasal septum derived progenitors

Microbiological, environmental and proteolytic aspects in chronic rhinosinusitis with nasal polyposis

Chronic rhinosinusitis is one of the most common chronic respiratory tract diseases affecting up to 15% of the adult population in the Western world. It may be perpetuated by factors predisposing to sinus ostial obstruction together with inflammatory changes in the sinus mucosa. Chronic rhinosinusitis is associated with asthma, and it may represent the same disease process. Chronic rhinosinusitis with nasal polyposis (CRSwNP) and asthma share also the characteristic inflammatory features and histopathologic feature of airway remodelling. Remodelling is considered as a key event in the pathogenesis of asthma. It is controlled by a delicate balance between the matrix metalloproteinases (MMPs) and their regulators. The purpose of the present study was to evaluate the microbiological findings, inflammatory features and MMP and tissue inhibitor of metalloproteinases-1 (TIMP-1) expression in CRSwNP. The results were related to the patient history, exposure to moisture and clinical outcome in order to find out possible explanations for the etiology and chronicity of CRSwNP. Bacterial culture results were similar in patients and in controls and do not explain the chronic course of CRSwNP. The presence of fungi seems to be more common in CRSwNP than chronic rhinosinusitis in general, and they should be actively searched for using microbiological as well as histological methods. Typical outdoor fungal species were found in nasal lavage samples taken from controls in the autumn but not in the winter, reflecting environmental exposure. Exposure to moisture was reported by 46% of the CRSwNP patients, which is in accordance to the Finnish general population. Exposed patients did not differ significantly from non-exposed subjects with regards to microbiological findings, tissue eosinophilia and clinical outcome. Significantly elevated levels of collagenase-2 (MMP-8) and interleukin (IL)-8 but not tumour necrosis factor-α were found in CRSwNP patients. In particular, the activation of mesenchymal-type MMP-8 but not polymorphonuclear-type MMP-8 was associated with elevated IL-8 levels. IL-8 and MMP-8 may form an inductive cytokine-proteinase cascade in CRSwNP pathogenesis and provide a target for novel therapies and a diagnostic tool for monitoring CRSwNP treatment. The proteolytic spectrum is different in eosinophilic and non-eosinophilic CRSwNP with the up-regulation of MMP-8 and MMP-9 in non-eosinophilic CRSwNP, suggesting different pathophysiology in these subgroups. The lack of MMP up-regulation was associated with a poor prognostic factor and worse clinical outcome, representing a possible synergic anti-inflammatory function of MMP-8 and MMP-9 in CRSwNP. This study provides new information about possible immunologic mechanisms in the pathogenesis of CRSwNP. The recently discovered anti-inflammatory/ defensive properties of MMP-8 and MMP-9 in animal models are reported for the first time in a clinical setting in human inflammatory diseases.

Polyvinylidene fluoride film based nasal sensor to monitor human respiration pattern: An initial clinical study

Design and development of a piezoelectric polyvinylidene fluoride (PVDF) thin film based nasal sensor to monitor human respiration pattern (RP) from each nostril simultaneously is presented in this paper. Thin film based PVDF nasal sensor is designed in a cantilever beam configuration. Two cantilevers are mounted on a spectacle frame in such a way that the air flow from each nostril impinges on this sensor causing bending of the cantilever beams. Voltage signal produced due to air flow induced dynamic piezoelectric effect produce a respective RP. A group of 23 healthy awake human subjects are studied. The RP in terms of respiratory rate (RR) and Respiratory air-flow changes/alterations obtained from the developed PVDF nasal sensor are compared with RP obtained from respiratory inductance plethysmograph (RIP) device. The mean RR of the developed nasal sensor (19.65 +/- A 4.1) and the RIP (19.57 +/- A 4.1) are found to be almost same (difference not significant, p > 0.05) with the correlation coefficient 0.96, p < 0.0001. It was observed that any change/alterations in the pattern of RIP is followed by same amount of change/alterations in the pattern of PVDF nasal sensor with k = 0.815 indicating strong agreement between the PVDF nasal sensor and RIP respiratory air-flow pattern. The developed sensor is simple in design, non-invasive, patient friendly and hence shows promising routine clinical usage. The preliminary result shows that this new method can have various applications in respiratory monitoring and diagnosis.

Evaluation of polyvinylidene fluoride nasal sensor to assess deviated nasal septum in comparision with peak nasal inspiratory flow measurements

Background: Deviated nasal septum (DNS) is one of the major causes of nasal obstruction. Polyvinylidene fluoride (PVDF) nasal sensor is the new technique developed to assess the nasal obstruction caused by DNS. This study evaluates the PVDF nasal sensor measurements in comparison with PEAK nasal inspiratory flow (PNIF) measurements and visual analog scale (VAS) of nasal obstruction. Methods: Because of piezoelectric property, two PVDF nasal sensors provide output voltage signals corresponding to the right and left nostril when they are subjected to nasal airflow. The peak-to-peak amplitude of the voltage signal corresponding to nasal airflow was analyzed to assess the nasal obstruction. PVDF nasal sensor and PNIF were performed on 30 healthy subjects and 30 DNS patients. Receiver operating characteristic was used to analyze the DNS of these two methods. Results: Measurements of PVDF nasal sensor strongly correlated with findings of PNIF (r = 0.67; p < 0.01) in DNS patients. A significant difference (p < 0.001) was observed between PVDF nasal sensor measurements and PNIF measurements of the DNS and the control group. A cutoff between normal and pathological of 0.51 Vp-p for PVDF nasal sensor and 120 L/min for PNIF was calculated. No significant difference in terms of sensitivity of PVDF nasal sensor and PNIF (89.7% versus 82.6%) and specificity (80.5% versus 78.8%) was calculated. Conclusion: The result shows that PVDF measurements closely agree with PNIF findings. Developed PVDF nasal sensor is an objective method that is simple, inexpensive, fast, and portable for determining DNS in clinical practice.

Packaging of Polyvinylidene fluoride nasal sensor for biomedical applications

This paper presents the design technique that has been adopted for packaging of Polyvinylidene fluoride (PVDF) nasal sensor for biomedical applications. The PVDF film with the dimension of length 10mm, width 5mm and thickness 28 mu m was firmly adhered on one end of plastic base (8mmx5mmx30 mu m) in such a way that it forms a cantilever configuration leaving the other end free for deflection. Now with the leads attached on the surface of the PVDF film, the cantilever configuration becomes the PVDF nasal sensor. For mounting a PVDF nasal sensor, a special headphone was designed, that can fit most of the human head sizes. Two flexible strings are soldered on either side of the headphone. Two identical PVDF nasal sensors were then connected to either side of flexible string of the headphone in such a way that they are placed below the right and left nostrils respectively without disturbing the normal breathing. When a subject wares headphone along with PVDF nasal sensors, two voltage signals due to the piezoelectric property of the PVDF film were generated corresponding to his/her nasal airflow from right and left nostril. The entire design was made compact, so that PVDF nasal sensors along with headphone can be made portable. No special equipment or machines are needed for mounting the PVDF nasal sensors. The time required for packaging of PVDF nasal sensors was less and the approximate cost of the entire assembly (PVDF nasal sensors + headphone) was very nominal.

Validation of polyvinylidene fluoride nasal sensor to assess nasal obstruction in comparison with subjective technique

Objective: The aim of this study is to validate the applicability of the PolyVinyliDene Fluoride (PVDF) nasal sensor to assess the nasal airflow, in healthy subjects and patients with nasal obstruction and to correlate the results with the score of Visual Analogue Scale (VAS). Methods: PVDF nasal sensor and VAS measurements were carried out in 50 subjects (25-healthy subjects and 25 patients). The VAS score of nasal obstruction and peak-to-peak amplitude (Vp-p) of nasal cycle measured by PVDF nasal sensors were analyzed for right nostril (RN) and left nostril (LN) in both the groups. Spearman's rho correlation was calculated. The relationship between PVDF nasal sensor measurements and severity of nasal obstruction (VAS score) were assessed by ANOVA. Results: In healthy group, the measurement of nasal airflow by PVDF nasal sensor for RN and LN were found to be 51.14 +/- 5.87% and 48.85 +/- 5.87%, respectively. In patient group, PVDF nasal sensor indicated lesser nasal airflow in the blocked nostrils (RN: 23.33 +/- 10.54% and LN: 32.24 +/- 11.54%). Moderate correlation was observed in healthy group (r = 0.710, p < 0.001 for RN and r = 0.651, p < 0.001 for LN), and moderate to strong correlation in patient group (r = 0.751, p < 0.01 for RN and r = 0.885, p < 0.0001 for LN). Conclusion: PVDF nasal sensor method is a newly developed technique for measuring the nasal airflow. Moderate to strong correlation was observed between PVDF nasal sensor data and VAS scores for nasal obstruction. In our present study, PVDF nasal sensor technique successfully differentiated between healthy subjects and patients with nasal obstruction. Additionally, it can also assess severity of nasal obstruction in comparison with VAS. Thus, we propose that the PVDF nasal sensor technique could be used as a new diagnostic method to evaluate nasal obstruction in routine clinical practice. (C) 2015 Elsevier Inc. All rights reserved.