Evaluation of new immunochromatographic assay kit for adenovirus detection in throat swab: comparison with culture and real-time PCR results

Potential Diagnostic and Prognostic Biomarkers for Adenovirus Respiratory Infection in Children and Young Adults

Human Adenoviruses (HAdV) are known to be potentially associated with strong inflammatory responses and morbidity in pediatric patients. Although most of the primary infections are self-limiting, the severity of clinical presentation, the elevation of the white blood cell count and inflammatory markers often mimic a bacterial infection and lead to an inappropriate use of antibiotics. In infections caused by HAdV, rapid antigen detection kits are advisable but not employed routinely; costs and feasibility of rapid syndromic molecular diagnosis may limit its use in the in-hospital setting; lymphocyte cultures and two-sampled serology are time consuming and impractical when considering the use of antibiotics. In this review, we aim to describe the principal diagnostic tools and the immune response in HAdV infections and evaluate whether markers based on the response of the host may help early recognition of HAdV and avoid inappropriate antimicrobial prescriptions in acute airway infections.

Know your enemy: Unexpected, pervasive and persistent viral and bacterial contamination of primary cell cultures

In biomedical research, cell culture contamination is one of the main culprits of experimental failure. Contamination sources and concomitant remedies are numerous and challenging to manage. We herein describe two cases of uncommon contamination of cell cultures that we encountered, and the successful determination and eradication strategies. The first case describes the infection with human adenovirus C that originated from pharyngeal tonsils used for isolation of primary tonsillar epithelial cells. It is known that viral contamination of in vitro cell cultures can occur symptomless and is therefore difficult to identify. The contamination was pervasive and persistent, as it was widely spread in flow cabinets and apparatus, and has caused a serious delay to our research projects and the inevitable loss of valuable (patient-derived) cell sources. Eradication was successful by formalin gas sterilization of the flow cabinet and elimination of all infected cell lines from our biobank after PCR-guided determination. Secondly, we encountered a spore-forming bacterium, namely Brevibacillus brevis, in our cell culture facility. This bacterium originated from contaminated tap water pipes and spread via regular aseptic culture techniques due to survival of the bacterial spores in 70% ethanol. B brevis overgrew the cultures within a few days after seeding of the primary cells. Chlorine solution effectively killed this spore-forming bacterium. Both cases of contamination were identified using DNA sequencing which enabled the deployment of targeted aseptic techniques for the elimination of the persistent contamination.

Evaluation of adenovirus amplified detection of immunochromatographic test using tears including conjunctival exudate in patients with adenoviral keratoconjunctivitis

BACKGROUND

We evaluated a novel silver amplification immunochromatography test for rapid detection of adenovirus (AdV) antigen equipped with an automated reader system using tears including conjunctival exudate in patients with adenoviral keratoconjunctivitis.

METHODS

Two kinds of immunochromatographic (IC) kits, a conventional IC kit for conjunctival scrapings (control kit) and an IC kit using tears including conjunctival exudate collected by pressing a filter paper strip on the conjunctiva (test kit), were tested on 90 patients who attended Migita Eye Clinic with suspected adenoviral conjunctivitis. The results of the test kits were automatically obtained by a specific reader, which was based on silver amplification immunochromatography system, in 15 min. The detection of AdV was confirmed by real-time polymerase chain reaction (PCR) method, and typing was performed by direct sequencing. Comparative dilution assay was carried out with the two kits, using AdV type 3 and type 54 strains.

RESULTS

The sensitivity of the control kit and test kit was 89.8% and 98.3%, respectively. The specificity of both kits was 100%. A significant difference in the sensitivities of the two IC kits against PCR positivity was observed (P < 0.01). A significant correlation was found between AdV DNA copy numbers on a logarithmic scale obtained with the two tests (P < 0.01). The sensitivity of the test kit was 32-64-fold higher than that of the control kit without silver amplification for both AdV types.

CONCLUSIONS

These results suggest that this novel amplified AdV detection kit using tears including conjunctival exudate is useful, because it decreases patients' discomfort from specimen collection and its sensitivity is significantly higher than that of the conventional IC kit.

Study of infectious conjunctivitis among children in rural areas of Qinghai province

Infectious conjunctivitis is no longer a common eye disease in cities and developed areas, but in remote mountainous regions of China where living conditions are relatively under-developed, the occurrence of infectious conjunctivitis remains a public health issue. Here, we evaluate the ratio of infectious conjunctivitis among primary school students in the rural areas of Xunhua, Huangyuan, and Huzhu Counties in the Qinghai province of China, and report the microorganisms involved in causing infection. Of the 765 eligible primary school students, 694 participated to this study (a response rateof 90.7%), 381 boys and 313 girls, with a mean age of 7.52 years (range 7-9 years). A clinical diagnosis of infectious conjunctivitis was returned for 238 of the 694 children examined. The ratio of infectious conjunctivitis in Xunhua County (46.64%) was higher compared to that in Huangyuan (26.67%; P=0.03) and Huzhu Counties (23.61%; P=0.02). The leading cause of conjunctivitis was bacterial, followed by chlamydial and viral. Our results show that there is a high ratio of infectious conjunctivitis among rural primary school students in Qinghai province.

Capturing and concentrating adenovirus using magnetic anionic nanobeads

We recently demonstrated how various enveloped viruses can be efficiently concentrated using magnetic beads coated with an anionic polymer, poly(methyl vinyl ether-maleic anhydrate). However, the exact mechanism of interaction between the virus particles and anionic beads remains unclear. To further investigate whether these magnetic anionic beads specifically bind to the viral envelope, we examined their potential interaction with a nonenveloped virus (adenovirus). The beads were incubated with either adenovirus-infected cell culture medium or nasal aspirates from adenovirus-infected individuals and then separated from the supernatant by applying a magnetic field. After thoroughly washing the beads, adsorption of adenovirus was confirmed by a variety of techniques, including immunochromatography, polymerase chain reaction, Western blotting, and cell culture infection assays. These detection methods positively identified the hexon and penton capsid proteins of adenovirus along with the viral genome on the magnetic beads. Furthermore, various types of adenovirus including Types 5, 6, 11, 19, and 41 were captured using the magnetic bead procedure. Our bead capture method was also found to increase the sensitivity of viral detection. Adenovirus below the detectable limit for immunochromatography was efficiently concentrated using the magnetic bead procedure, allowing the virus to be successfully detected using this methodology. Moreover, these findings clearly demonstrate that a viral envelope is not required for binding to the anionic magnetic beads. Taken together, our results show that this capture procedure increases the sensitivity of detection of adenovirus and would, therefore, be a valuable tool for analyzing both clinical and experimental samples.

Clinical practice guideline: tonsillitis I. Diagnostics and nonsurgical management

More than 120,000 patients are treated annually in Germany to resolve repeated episodes of acute tonsillitis. Therapy is aiming at symptom regression, avoidance of complications, reduction in the number of disease-related absences in school or at work, increased cost-effectiveness and improved quality of life. The purpose of this part of the guideline is to provide clinicians in any setting with a clinically focused multi-disciplinary guidance through different conservative treatment options in order to reduce inappropriate variation in clinical care, improve clinical outcome and reduce harm. Surgical management in terms of intracapsular as well as extracapsular tonsillectomy (i.e. tonsillotomy) is the subject of part II of this guideline. To estimate the probability of tonsillitis caused by β-hemolytic streptococci, a diagnostic scoring system according to Centor or McIsaac is suggested. If therapy is considered, a positive score of ≥3 should lead to pharyngeal swab or rapid test or culture in order to identify β-hemolytic streptococci. Routinely performed blood tests for acute tonsillitis are not indicated. After acute streptococcal tonsillitis, there is no need to repeat a pharyngeal swab or any other routine blood tests, urine examinations or cardiological diagnostics such as ECG. The determination of the antistreptolysin O-titer (ASLO titer) and other antistreptococcal antibody titers do not have any value in relation to acute tonsillitis with or without pharyngitis and should not be performed. First-line therapy of β-hemolytic streptococci consists of oral penicillin. Instead of phenoxymethylpenicillin–potassium (penicillin V potassium), also phenoxymethlpenicillin–benzathine with a clearly longer half-life can be used. Oral intake for 7 days of one of both the drugs is recommended. Alternative treatment with oral cephalosporins (e.g. cefadroxil, cefalexin) is indicated only in cases of penicillin failure, frequent recurrences, and whenever a more reliable eradication of β-hemolytic streptococci is desirable. In cases of allergy or incompatibility of penicillin, cephalosporins or macrolides (e.g. Erythromycin-estolate) are valuable alternatives.