Fetal and placental infection with SARS-CoV-2 in early pregnancy.

To date, mother-to-fetus transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), responsible for the coronavirus disease 2019 (COVID-19) pandemic, remains controversial. Although placental COVID-19 infection has been documented in some cases during the second- and third-trimesters, no reports are available for the first trimester of pregnancy, and no SARS-CoV-2 protein has been found in fetal tissues. We studied the placenta and fetal organs from an early pregnancy miscarriage in a COVID-19 maternal infection by immunohistochemical, reverse transcription quantitative real-time polymerase chain reaction, immunofluorescence, and electron microscopy methods. SARS-CoV-2 nucleocapsid protein, viral RNA, and particles consistent with coronavirus were found in the placenta and fetal tissues, accompanied by RNA replication revealed by double-stranded RNA (dsRNA) positive immunostain. Prominent damage of the placenta and fetal organs were associated with a hyperinflammatory process identified by histological examination and immunohistochemistry. The findings provided in this study document that congenital SARS-CoV-2 infection is possible during the first trimester of pregnancy and that fetal organs, such as lung and kidney, are targets for coronavirus. The infection and multi-organic fetal inflammation produced by SARS-CoV-2 during early pregnancy should alert clinicians in the assessment and management of pregnant women for possible fetal consequences and adverse perinatal outcomes.

The sigma factor SigD of Mycobacterium tuberculosis putatively enhances gene expression of the septum site determining protein under stressful environments.

This work examined the expression of the septum site determining gene (ssd) of Mycobacterium tuberculosis CDC1551 and its ∆sigD mutant under different growing conditions. The results showed an up-regulation of ssd during stationary phase and starvation conditions, but not during in vitro dormancy, suggesting a putative role for SigD in the control of ssd expression mainly under lack-of-nutrients environments. Furthermore, we elucidated a putative link between ssd expression and cell elongation of bacilli at stationary phase. In addition, a -35 sigD consensus sequence was found for the ssd promoter region, reinforcing the putative regulation of ssd by SigD, and in turn, supporting this protein role during the adaptation of M. tuberculosis to some stressful environments.