Highly sensitive extraction-free saliva-based molecular assay for rapid diagnosis of SARS-CoV-2.

The COVID-19 pandemic highlighted the necessity of fast, sensitive, and efficient methods to test large populations for respiratory viruses. The "gold standard" molecular assays for detecting respiratory viruses, such as quantitative polymerase chain reaction (qPCR) and reverse transcription qPCR (RT-qPCR), rely on invasive swab samples and require time-consuming and labor-intensive extraction processes. Moreover, the turnaround time for RT-qPCR-based assays is too lengthy for rapid screening. Extraction-free saliva-based methods provide a non-invasive sampling process with a fast turnaround time and are suitable for high-throughput applications. However, when used with a standard RT-qPCR system, the absence of extraction significantly reduces the assays' sensitivity. Here, using a novel optical modulation biosensing (OMB) platform, we developed a rapid and highly sensitive extraction-free saliva-based molecular assay. We blindly tested 364 paired nasopharyngeal swabs and saliva samples from suspected SARS-CoV-2 cases in Israel. Compared with the gold standard swab-based RT-qPCR assay, the sensitivity of the extraction-free saliva-based OMB assay is 90.7%, much higher than the sensitivity of extraction-free saliva-based RT-qPCR assay (77.8%) with similar specificity (95.3% and 97.6%, respectively). Moreover, out of 12 samples identified by the OMB-based assay as positive, 8 samples were collected from hospitalized patients in a COVID-19 ward and were verified to be SARS-CoV-2-positive upon admission, indicating that the actual clinical sensitivity and specificity of the OMB assay are higher. Considering its user-friendly saliva-based protocol, short and cost-effective extraction-free process, and high clinical accuracy, the OMB-based molecular assay is very suitable for high-throughput testing of large populations for respiratory viruses. IMPORTANCE: Three years after the SARS-CoV-2 outbreak, there are no molecular tests that combine low-cost and straightforward sample preparation, effective sample handling, minimal reagent and disposable requirements, high sensitivity, and high throughput required for mass screening. Existing rapid molecular techniques typically sacrifice certain requirements to meet others. Yet, localized outbreaks of novel viral diseases happen daily in different parts of the world. In this context, respiratory diseases are of specific importance, as they are frequently airborne and highly contagious, with the potential for a rapid global spread. The widely accepted opinion is that another pandemic is just a question of time. To ensure that the containment efforts for the upcoming "disease X" are successful, introducing rapid, high-throughput, and highly sensitive diagnostic methods for detecting and identifying pathogens is critical. A few months into the pandemic, saliva was suggested as a diagnostic matrix for SARS-CoV-2 detection. The collection of saliva does not require swabs and is minimally invasive. In particular, extraction-free saliva-based assays require fewer reagents and disposables, and therefore are faster and cheaper, offering an appealing alternative for low-income countries. Unfortunately, current extraction-free saliva-based detection methods, such as direct RT-qPCR or isothermal amplification, have either low sensitivity or low throughput. Therefore, we believe that the presented highly sensitive ht-OMBi platform and the extraction-free saliva-based molecular assay can become an essential tool in the infectious disease monitoring toolbox.

Exploring the relationship between cycle threshold values and oral manifestations in COVID-19: a comprehensive overview.

OBJECTIVE: This cross-sectional study aimed to compare oral manifestations between severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2)-positive and SARS-CoV-2-negative patients and to examine associations between oral symptoms, Ct values of E and N SARS-CoV-2 viral genes, and the implications of low Ct values indicating a high viral load, which is a predictive factor for the outcome of COVID-19. METHODS: A total of 353 participating patients were aged ≥18 years with clinical manifestations of COVID-19 infection and tested for SARS-CoV-2 carriage at the medical center, by reverse transcriptase polymerase chain reaction (RT-PCR). All patients filled out an anonymous digital questionnaire regarding oral and general symptoms and overall medical health.  Results: A significant association was found between SARS-CoV-2 carriage and dry mouth, unpleasant taste and changes in taste (p < 0.001); for example, 37.4% of the 147 SARS-CoV-2- positive participants had a dry mouth, compared to 18.9% of the 206 SARS-CoV-2- negative participants. Oral blisters were experienced by patients with an E gene Ct value of 10-20 (50%) or 21-30 (50%) (p = 0.041). Bad breath, dry mouth, unpleasant taste and changes in taste were mostly present in participants whose Ct values of both E and N genes were between 21 and 30.  Conclusions: This study found significant associations between low Ct values of E and N SARS-CoV-2 viral genes and high viral load, indicating that Ct values can serve as predictive factors for COVID-19 outcomes. The findings suggest that while oral symptoms are present, the Ct values and associated high viral loads are more critical indicators of disease severity and prognosis.

[Rare infection--prolonged A. naeslundii bacteremia caused by severe caries].

Actinomyces is an anaerobic, gram positive, rod shape bacteria that doesn't create spores. Actinomyces is part of the mouth, intestines, vagina and upper respiratory system flora. The infection appears mostly on the face, neck, abdomen and pelvis in cases of mucosa injury and most common in immunosuppressed patients. The spread of Actinomyces through the blood system is rare. In this article we present a 9 year old male patient with no history of diseases who was diagnosed with prolonged bacteremia of A. naeslundii without specific infection excluding severe caries. Characterization of bacteria from the blood culture was performed by molecular biology and the patient was treated with Ampicillin and tooth extraction that led to the disappearance of the bacteremia.

The Possible Role of Dental Implants in the Etiology and Prognosis of Osteomyelitis: A Retrospective Study.

PURPOSE: The aim of this study was to describe the clinical outcome of osteomyelitis of the mandible or maxilla following dental implants. A detailed treatment protocol is also proposed. MATERIALS AND METHODS: Electronic data of all the patients who were treated between October 2009 and November 2014, in three maxillofacial surgical departments, were reviewed. Computed databases were searched for the diagnosis of osteomyelitis of the mandible or maxillas (ICD9 code 526.2), and medical files were analyzed. Treatment outcome was considered successful if only primary treatment (debridement and antibiotic therapy) was applied. Statistical analysis was performed to compare treatment outcomes in the different etiologic groups. RESULTS: The cohort included 29 men and 25 women, with histologically and clinically proven osteomyelitis. The mean age was 59 years (range, 24 to 70 years). Forty patients had complete remission, as opposed to 14 patients who failed the primary treatment and required a more aggressive surgical intervention (11 had segmental mandibulectomy, 2 patients had marginal mandibulectomy, and 1 patient had maxillectomy). Most failures were in the dental implantation group. A previous dental implant was an independent factor for primary treatment failure and the need for aggressive surgical intervention (P = .0001). CONCLUSION: The results of this retrospective study suggest that a previous dental implant is an independent predictive factor of failure in primary treatment in osteomyelitis of the mandible or maxilla. Also, dental implant-induced osteomyelitis is a rare pathology, but it presents an aggressive subtype of osteomyelitis, and requires a broader and more comprehensive management.