Aptamer-based approaches for the detection of waterborne pathogens

Waterborne ailments pose a serious threat to public health and are a huge economic burden. Lack of hygiene in drinking and recreational water is the chief source of microbial pathogens in developing countries. Poor water quality and sanitation account for more than 3.4 million deaths a year worldwide. This has urged authorities and researchers to explore different avenues of pathogen detection. There is a growing demand for rapid and reliable sensor technologies, in particular those that can detect in situ and perform in harsh conditions. Some of the major waterborne pathogens include Vibrio cholerae, Leptospira interrogans, Campylobacter jejuni, Shigella spp., enterotoxigenic Escherichia coli, Clostridium difficile, Cryptosporidium parvum, Entamoeba histolytica, and Hepatitis A virus. While conventional methods of pathogen detection like serodiagnosis and microbiological methods have been superseded by nucleic acid amplification methods, there is still potential for improvement. This review provides an insight into aptamers and their utility in the form of aptasensors. It discusses how aptamer-based approaches have emerged as a novel strategy and its advantages over more resource-intensive and complex biochemical approaches.

The spectrum of pulmonary aspergillosis

Notable progress has been made in the past years in the classification, diagnosis and treatment of pulmonary aspergillosis. New criteria were proposed by the Working Group of the International Society for Human and Animal Mycology (ISHAM) for the diagnosis of allergic bronchopulmonary aspergillosis (ABPA). The latest classification of chronic pulmonary aspergillosis (CPA) suggested by the European Society for Clinical Microbiology and Infectious Diseases (ESCMID) has become widely accepted among clinicians. Subacute invasive pulmonary aspergillosis is now considered a type of CPA, yet it is still diagnosed and treated similarly to invasive pulmonary aspergillosis (IPA). Isavuconazole, an extended-spectrum triazole, has recently been approved by the Food and Drug Administration (FDA) and the European Medicines Agency (EMA) for the treatment of IPA. The most recent Infectious Diseases Society of America (IDSA) guidelines strongly recommend reducing mold exposure to patients at high risk for pulmonary aspergillosis. The excessive relapse rate following discontinuation of therapy remains a common reality to all forms of this semi-continuous spectrum of diseases. This highlights the need to continuously reassess patients and individualize therapy accordingly. Thus far, the duration of therapy and the frequency of follow-up have to be well characterized.

Th2 Immunological Inflammation in Allergic Fungal Sinusitis, Nonallergic Eosinophilic Fungal Sinusitis, and Chronic Rhinosinusitis

Background

Noninvasive fungal sinusitis is a heterogenous group of conditions including allergic fungal sinusitis (AFS) and nonallergic eosinophilic fungal sinusitis (NEFS). Th2-mediated cascades have been postulated to be the major inflammatory response in patients with AFS although other mechanisms also may be involved. The detailed mucosal Th2 cytological status of NEFS still has not been studied in great depth.

Methods

Using a meticulous patient selection algorithm over a 2-year period, infundibular mucosal tissue from patients with AFS, NEFS, chronic rhinosinusitis (CRS), and normal controls was studied (n = 59). Immunohistochemistry for mast cells, eosinophils, and immunoglobulin E (IgE) cells was performed and cell counts per unit area were measured.

Results

Mast cell, eosinophil, and IgE+ cell numbers were significantly raised in patients with AFS, NEFS, and CRS when compared with controls. There was no significant difference between cell numbers in patients with AFS and NEFS.

Conclusion

Patients with AFS exhibit a classic Th2 inflammatory response in nasal mucosal tissue with NEFS and CRS patients showing evidence of a similar Th2 cascade, including the presence of IgE+ cells.

Eosinophil ETosis and DNA Traps: a New Look at Eosinophilic Inflammation

The traditional paradigm of eosinophils as end-stage damaging cells has mainly relied on their release of cytotoxic proteins. Cytokine-induced cell survival and secretion of granular contents from tissue-dwelling eosinophil are thought to be important mechanisms for eosinophilic inflammatory disorders, although the occurrence of cytolysis and its products (i.e., free extracellular granules) has been observed in affected lesions. Recent evidence indicates that activated eosinophils can exhibit a non-apoptotic cell death pathway, namely extracellular trap cell death (ETosis) that mediates the eosinophil cytolytic degranulation. Here, we discuss the current concept of eosinophil ETosis which provides a new look at eosinophilic inflammation. Lessons from eosinophilic chronic rhinosinusitis revealed that ETosis-derived DNA traps, composed of stable web-like chromatin, contribute to the properties of highly viscous eosinophilic mucin and impairments in its clearance. Intact granules entrapped in DNA traps are causing long-lasting inflammation but also might have immunoregulatory roles. Eosinophils possess a way to have post-postmortem impacts on innate immunity, local immune response, sterile inflammation, and tissue damage.

The fungal microbiome in chronic rhinosinusitis: richness, diversity, postoperative changes and patient outcomes

BACKGROUND

Our understanding of fungi in chronic rhinosinusitis (CRS) has been limited by previously employed detection techniques. This study examines the fungal component of the microbiome in CRS patients and controls using a highly sensitive culture-independent molecular technique. The aims of this study include the characterization of fungal richness, prevalence, abundance, temporal changes, and their relationship with patient outcomes.

METHODS

Swabs were collected from the sinuses of 23 CRS patients and 11 controls. Collection occurred intraoperatively, and at 6 and 12 weeks postoperatively. DNA was extracted from the swabs and fungal outcomes were determined through 18S ribosomal DNA (rDNA) fungal tag-encoded FLX amplicon pyrosequencing.

RESULTS

Fungi were ubiquitous to all patients. A total of 207 fungal genera were detected, with a mean sample richness of 8.18 and 12.14 in the control and CRS groups, respectively. Malassezia was detected in all patients at surgery and was also the most abundant. Postoperatively, fungal richness decreased (p < 0.05) and was associated with declines in the prevalence of Fusarium and Neocosmospora (p < 0.05). Neocosmospora was also less abundant postoperatively (p < 0.05). No correlations were found with quality of life.

CONCLUSION

This is the first study to use a highly sensitive pyrosequencing technique to reveal the true diversity of fungi in the sinuses of CRS patients and postoperative changes in richness. The presence of Malassezia, a genus not previously described in the sinuses, is of great interest, and its potential as a disease modifier should see further investigation given its association with atopic disease.

Pretreatment of sinus aspirates with dithiothreitol improves yield of fungal cultures in patients with chronic sinusitis

BACKGROUND

Mold pathogens are a leading cause of chronic rhinosinusitis. Successful isolation of mold on culture is helpful in establishing a diagnosis and guiding therapy. Though mucolytic agents are commonly used in European countries, they are not part of everyday use in North America. In this case-control prospective study, we investigated the yield of fungal culture before and after treatment of sinus aspirates with the mucolytic agent dithiothreitol in a United States hospital.

METHODS

Over a 5-month period during 2011-2012, 359 sinus aspirates from 294 patients with symptoms suspicious for chronic sinusitis or allergic fungal sinusitis were collected. Aspirates were cultured on fungal medium before and after treatment with dithiothreitol.

RESULTS

Of the 359 pairs of cultures, 62 (17.3%) demonstrated mold growth on at least 1 of the plates, 9 (14.5%) of which grew more than 1 species of mold. A total of 75 molds were identified, 41 (54.7%) of which were successfully cultured only when the mucus was pretreated with dithiothreitol (p < 0.0001). Quantitatively, more colonies grew from dithiothreitol-treated mucus than from direct-inoculation (p < 0.0001).

CONCLUSION

This study confirms improved recovery of mold from sinus cultures after pretreatment of samples with dithiothreitol. Further studies are needed to correlate these findings with clinical outcome.

Fungicidal activity of lysozyme is inhibited in vitro by commercial sinus irrigation solutions

BACKGROUND

Lysozyme is an innate immune peptide with bactericidal and fungicidal activity (FA). Despite increased expression of lysozyme protein in chronic rhinosinusitis (CRS) sinus mucosa, CRS patients experience repeated bacterial and/or fungal infections. Commercial sinus irrigation solutions are often used to provide symptomatic relief. However, one of the mechanisms of action of lysozyme involves ionic interactions with the microbial cell wall, which may be inhibited by ionic solutions such as commercial sinus irrigation solutions.

OBJECTIVE

Determine if the FA of lysozyme is reduced in the presence of solutions with increasing ionic strength and inhibited in the presence of commercial sinus irrigation solutions.

METHODS

Using an in vitro colony-forming unit (CFU) assay, the FA of lysozyme (5 μM) was tested against a fungi commonly isolated from CRS patients, Aspergillus fumigatus, in solutions of increasing ionic strength or commercial sinus irrigation solutions. FA was presented as percent of control.

RESULTS

FA of lysozyme against A. fumigatus was 95% in a 21-mM ionic strength solution. However, with increasing ionic strength, FA decreased and was abolished in a 46-mM ionic strength solution. Commercial sinus irrigation solutions abolished the FA of lysozyme against A. fumigatus.

CONCLUSION

The in vitro FA of lysozyme is dependent on the ionic strength of the solution. The use of sinus irrigation solutions should be further evaluated with regard to maintaining functional activity of cationic antimicrobial peptides involved in sinonasal innate immunity.

Human lysozyme has fungicidal activity against nasal fungi

BACKGROUND

The cationic antimicrobial peptide lysozyme is the most prevalent innate immune protein in nasal secretions but there is a paucity of research regarding its role in paranasal sinus disease. Lysozyme is generally regarded as an antibacterial agent; however, some data suggest activity toward yeast. This study was designed to determine if lysozyme displays fungicidal activity toward fungi commonly identified in patients with chronic rhinosinusitis (CRS) or fungal sinusitis.

METHODS

Using a colony-forming unit assay the fungicidal activity of lysozyme (0, 0.5, 5, and 50 micromolar; 0- to 7-hour treatment) was tested against strains of Aspergillus fumigatus, the yeast Candida albicans, and other fungi commonly identified in mucin of patients with CRS. Fungi cultured directly from the mucin of two CRS patients were also tested to determine if they were resistant to the fungicidal activity of lysozyme.

RESULTS

The fungicidal effect of lysozyme was both concentration and time dependent. After 7-hour treatment lysozyme (5 micromolar) had >80% fungicidal activity against A. fumigatus, Penicillium sp., Acremonium sp., C. albicans, and Candida parapsilosis. The fungicidal activity of lysozyme toward Alternaria alternata could not be determined. Lysozyme was also fungicidal toward the clinical isolates A. fumigatus and Aspergillus terreus cultured from the mucin of CRS patients.

CONCLUSION

Lysozyme displays fungicidal activity toward many fungi commonly identified in patients with CRS, as well as clinical fungi isolates cultured from the mucin of CRS patients. Additional studies are required to determine the regulation of lysozyme in CRS.

Patient satisfaction and treatment outcome of fungus ball rhinosinusitis treated by functional endoscopic sinus surgery

Fungal rhinosinusitis is an important clinical problem with diverse manifestations. Although many literatures had found low recurrence rate after surgical treatment of fungus ball rhinosinusitis, patient satisfaction and treatment outcomes (symptom-free and symptom improvement rate, etc.) for fungus ball sinusitis are not yet well established. The purpose of this study is to estimate the patient satisfaction and treatment outcome in patients with fungus ball rhinosinusitis undergoing functional endoscopic sinus surgery (FESS). Medical records of consecutive patients with diagnosed fungus ball rhinosinusitis treated by FESS between 1995 and 2005 were reviewed retrospectively. The post-operative improvement in individual symptom was assessed by chart review and telephone visiting. Ninety consecutive patients (21 men and 69 women) were eligible for the study. Six patients (7%) presented bilateral fungus ball rhinosinusitis. Multiple paranasal sinus fungus ball involvements were found in 48 patients (53%). Complete resolution of complaints with respect to nasal discharge, postnasal drip, cough with sputum, nasal bleeding, fetid odor of nose, olfactory dysfunction, nasal obstruction, headache, and facial pain or pressure were described in 74 patients (82%). The overall patient satisfaction rate was 96%. The estimated recurrence rate of fungus ball rhinosinusitis treated with FESS was 3%, with a mean follow-up of 81 months. Treatment protocol of fungus ball rhinosinusitis with FESS and without postoperative antifungal drugs is efficient because of very low recurrence rate, high patient satisfaction, and very high symptom-free rate. Furthermore, the obvious difference of symptom-free rate between fungus ball rhinosinusitis and chronic rhinosinusitis highlights the need of further studies to discover the pathophysiology of fungal sinusitis.

The role of fungi in the airway of chronic rhinosinusitis patients

PURPOSE OF REVIEW

To analyze the role of fungi in the upper and lower airway in chronic rhinosinusitis patients.

RECENT FINDINGS

Recently, the involvement of the lower airway (as asthma, small airway disease and bronchial hyperresponsiveness) in chronic rhinosinusitis patients had been documented. Fungal spores after inhalation are submerged in the aqueous lining layers of the airway. The site depends on the size of the inhaled spores. The process of inhalation, retention and clearance of fungal spores may explain the positive culture results in both normal subjects and in most chronic rhinosinusitis patients. Fungal culture of different parts of the upper and lower airway in chronic rhinosinusitis patients had no correlation with cellular changes (local eosinophilia) and other clinical parameters. In chronic rhinosinusitis, with persistence of the chronic inflammatory process, the cells may be activated nonspecifically.

SUMMARY

The role played by fungi in most chronic rhinosinusitis patients as the target antigen of initiation of such chronic inflammation is still debated. With the presence of chronic eosinophilic inflammation in chronic rhinosinusitis, an exaggerated reaction to various inhaled antigens is anticipated. The role of fungi will be confirmed only when T cells within the sinuses are shown to be actively responding to fungal antigens cultured from the sinus and with the demonstration that their elimination will stop the disease.

Bibliography. Current world literature. Nose and paranasal sinuses

PURPOSE OF REVIEW

Patients with advanced head and neck cancer are being treated with chemo-radiotherapy, and life is being prolonged, with or without persistent disease, for longer than was previously. Hypercalcaemia may present in patients with advanced or disseminated head and neck cancer, and, as such, these patients may present to a larger variety of clinicians for advice concerning their symptoms and illness. Modes of presentation of hypercalcaemia and treatment strategies are reviewed.

RECENT FINDINGS

There were previously few large series of head and neck cancer patients diagnosed with hypercalcaemia, which may or may not have been related to their cancer being treated. Investigations, by way of blood/serum calcium level, may identify such patients. Patients with cancer-related hypercalcaemia have a poor prognosis, but many may respond temporarily to treatment when offered, with an improvement of their quality of life and death.

SUMMARY

Hypercalcaemia should and must be considered in all patients who have or possibly have a diagnosis of a head and neck cancer and who present unwell with symptoms of fatigue, lethargy and somnolence. Investigation must include serum calcium (corrected for serum albumin binding) and parathyroid hormone level. Patients may be treated by a combination of rehydration and bisulphonate therapy until the serum calcium is reduced to a level below 3 mmol/l. The majority of patients diagnosed with hypercalcaemia due to head and neck malignancy die of their diseases in the short term, but some may enjoy a prolongation of life with reasonable quality if diagnosed and treated aggressively.

Fungal speciation using quantitative polymerase chain reaction (QPCR) in patients with and without chronic rhinosinusitis

OBJECTIVES/HYPOTHESIS

The objectives of this study were to determine the mycology of the middle meatus using an endoscopically guided brush sampling technique and polymerase chain reaction laboratory processing of nasal mucous; to compare the mycology of the middle meatus in patients with sinus disease with subjects without sinus disease; to compare the responses on two standardized quality-of-life survey forms between patients with and without sinusitis; and to determine whether the presence of fungi in the middle meatus correlates with responses on these data sets.

STUDY DESIGN

The authors conducted a single-blind, prospective, cross-sectional study.

METHODS

Patients with sinus disease and a control group without sinus disease were enrolled in the study. A disease-specific, validated Sinonasal Outcomes Test survey (SNOT-20) was completed by the subjects and a generalized validated Medical Outcomes Short Form 36 Survey (SF-36) was also completed. An endoscopically guided brush sampling of nasal mucous was obtained from the middle meatus. Fungal specific quantitative polymerase chain reaction (QPCR) was performed on the obtained sample to identify one of 82 different species of fungus in the laboratory. Statistical analysis was used to categorize the recovered fungal DNA and to crossreference this information with the outcomes surveys.

RESULTS

The fungal recovery rate in the study was 45.9% in patients with sinus disease and 45.9% in control subjects. Patients with chronic rhinosinusitis had a mean SNOT-20 score of 1.80 versus the control group mean score of 0.77 (P < .0001). SF-36 data similarly showed a statistically significant difference between diseased and control populations with controls scoring a mean of 80.37 and patients with chronic rhinosinusitis scoring a mean of 69.35 for a P value of .02. However, no statistical significance could be ascribed to the presence or absence of fungi recovered, the type of fungi recovered, or the possible impact of fungi on the quality-of-life survey results.

CONCLUSION

The recovery rate of fungi from the middle meatus of patients with chronic rhinosinusitis and a control population without chronic rhinosinusitis is 45.9% using QPCR techniques. No direct causation with regard to fungal species or presence was proven; however, a species grouping for future studies is proposed based on trends in this data and other reports. Disease-specific outcomes surveys revealed a statistically significant difference between the two groups.