No abstract

We prospectively compared the efficacy of PCR detection of SARS-CoV-2 between paired nasopharyngeal and saliva samples in 76 patients including ten COVID-19 patients. The overall concordance rate of the virus detection between the two samples was 97.4% (95%CI, 90.8-99.7). Viral load was equivalent in COVID-19 patients, but the virus tended to disappear earlier in saliva at convalescent phase compared to nasopharyngeal samples. These results suggest that saliva is a reliable noninvasive alternative to nasopharyngeal swabs and facilitate widespread PCR testing in the face of shortages of swabs and protective equipment without posing a risk to healthcare workers.

The mechanism underlying bacterial conjugation through protozoa was investigated. or bacteria had no effect on conjugation frequency. Co-localization of green fluorescent protein-expressing E. coli and PKH67-vital stained E. coli was observed in the same ciliate vesicles, suggesting that both donor and recipient bacteria had accumulated in the same vesicle. Kanamycin-resistant Escherichia coliIn this study, the conjugation frequency of bacteria was found to be significantly higher in vesicles purified from ciliates than those in culture suspension. We conclude that ciliates rapidly enhance the conjugation of E. coli strains through bacterial accumulation in vesicles.

Rapid and simple point-of-care detection of SARS-CoV-2 is an urgent need to prevent pandemic. Reverse transcription loop-mediated isothermal amplification (RT-fLAMP) can detect SARS-CoV-2 more rapidly than RT-PCR. Saliva is non-invasive specimen suitable for mass-screening, but data comparing utility of nasopharyngeal swab (NPS) and saliva in RT-FLAMP test are lacking and it remains unclear whether SARS-CoV-2 could be detected by direct processing of samples without the need for prior RNA extraction saliva. In this study, we compared utility of saliva and NPS samples for the detection of SARS-CoV-2 by a novel RT-fluorescence LAMP (RT-fLAMP). The sensitivity and specificity of the RT-fLAMP with RNA extraction were 97% and 100%, respectively, with equivalent utility of NPS and saliva. However, sensitivity was decreased to 71% and 47% in NPS and saliva samples without RNA extraction, respectively, suggesting that RNA extraction process may be critical for the virus detection by RT-fLAMP.

Rapid detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is critical for the diagnosis of coronavirus disease 2019 (COVID-19) and preventing the spread of the virus. A novel detection kitthe 2019 Novel Coronavirus Detection Kit (nCoV-DK)halves the detection time by eliminating the steps of RNA extraction and purification. We evaluated the concordance between the nCoV-DK and direct PCR. The virus was detected in 53/71 specimens (74.6%) by direct PCR and in 55/71 specimens (77.5%) by nCoV-DK; the overall concordance rate was 94.4%: 95.2% for nasopharyngeal swab, 95.5% for saliva, and 85.7% for sputum. The nCoV-DK test effectively detects SARS-CoV-2 in all types of sample including saliva, while reducing the time required for detection, labor, and the risk of human error.