Tuberculosis/COVID-19 co-infection detected in a single sputum sample using a rapid molecular test.

Tuberculosis (TB) and COVID-19 affect the lungs and are transmitted mainly by aerosols or particles of saliva from infected persons. Clinical similarities between diseases can affect correct diagnosis. Individuals belonging to the population deprived of liberty (PDL) are at increased risk of contagion due to precarious sanitary conditions and overcrowded environments. A variety of specimens may be suitable for the diagnosis of COVID-19, using molecular diagnostic techniques; however, there is little data on the analysis of sputum samples with the Xpert Xpress SARS-CoV-2® for the diagnosis of COVID-19, especially in this population group. The present study reports a case of TB and COVID-19 co-infection detected in sputum from an individual belonging to the PDL. For the detection, it used the GeneXpert platform (Cepheid, USA). Mycobacterium tuberculosis complex (MTC) was detected using the Xpert MTB/RIF Ultra® cartridge and SARS-CoV-2 was detected using the Xpert Xpress SARS-CoV-2® cartridge. The genes IS6110 and IS1081 were detected within 80 min indicating the presence of MTC, with no mutations related to resistance to rifampicin. The SARS-CoV-2 E and N2 genes were detected within 45 min. The result was confirmed by RT-qPCR with detection of E, N, and RdRP/S genes in the sputum and nasopharyngeal (NP) specimens. Rapid diagnoses that allow the identification and differentiation of such diseases are important for adequate epidemiological surveillance, isolation of infected individuals, and interruption of the transmission chain. Using the GeneXpert platform, specimens can be tested as soon as they are received, without the need for prior preparation. The US Food and Drug Administration has issued emergency authorization for the use of the Cepheid Xpert Xpress SARS-CoV-2 for the rapid detection of SARS-CoV-2 using specimens from a NP or nasal wash/aspirate. The case presented here gains an innovation with the use of the sputum to COVID-19 diagnosis.

Alternative SARS-CoV-2 detection protocol from self-collected saliva for mass diagnosis and epidemiological studies in low-incoming regions.

Until mass vaccination befalls, control of the new betacoronavirus-associated severe acute respiratory syndrome pandemic (SARS-CoV-2) is based on decreasing virus circulation by social distancing and blocking transmission foci after diagnosis. Globally adopted SARS-CoV-2 diagnostic criteria embrace viral RNA detection by quantitative reverse-transcription polymerase chain reaction (qRT-PCR) on nasopharynx secretions, which requires healthcare facilities and specialized personnel for sample collection. To develop an alternative protocol, hydrophilic cotton as the material and saliva as the source for biological sample collection in qRT-PCR/RT-endpoint-PCR SARS-CoV-2 diagnostic methods prepared with local consumables were evaluated using 99 archived nasopharynx samples previously diagnosed as positive for SARS-CoV-2 and 111 prospective saliva samples pared with nasopharynx samples from patients attending the local reference ABC Medical School diagnostic laboratory. The kappa agreement coefficient between the SARS-CoV-2 qRT-PCR and RT-endpoint-PCR was k = 0.97 (95 % CI 0.92-1.00) and k = 0.90 (95 % CI 0.81-0.99), respectively, on SARS-CoV-2-positive archived samples, with the initial qRT-PCR CT under 25. The agreement coefficient of the SARS-CoV-2 alternative saliva diagnostic protocol, when used to test the paired nasopharynx samples, was k = 0.79 (95 % CI 0.56-1,00). These data support that the SARS-CoV-2 diagnostic assay based on self-collected saliva on cotton represents an alternative protocol for mass diagnosis and epidemiological studies in low-income regions.