Attenuation of the Sensing Capabilities of PhoQ in Transition to Obligate Insect–Bacterial Association

Sodalis glossinidius, a maternally inherited endosymbiont of the tsetse fly, maintains genes encoding homologues of the PhoP-PhoQ two-component regulatory system. This two-component system has been extensively studied in facultative bacterial pathogens and is known to serve as an environmental magnesium sensor and a regulator of key virulence determinants. In the current study, we show that the inactivation of the response regulator, phoP, renders S. glossinidius sensitive to insect derived cationic antimicrobial peptides (AMPs). The resulting mutant strain displays reduced expression of genes involved in the structural modification of lipid A that facilitates resistance to AMPs. In addition, the inactivation of phoP alters the expression of type-III secretion system (TTSS) genes encoded within three distinct chromosomal regions, indicating that PhoP-PhoQ also serves as a master regulator of TTSS gene expression. In the absence of phoP, S. glossinidius is unable to superinfect either its natural tsetse fly host or a closely related hippoboscid louse fly. Furthermore, we show that the S. glossinidius PhoQ sensor kinase has undergone functional adaptations that result in a substantially diminished ability to sense ancestral signals. The loss of PhoQ's sensory capability is predicted to represent a novel adaptation to the static symbiotic lifestyle, allowing S. glossinidius to constitutively express genes that facilitate resistance to host derived AMPs

Quality of Life and Persistence of Symptoms in Outpatients after Recovery from COVID-19

Background and Objectives: Patients infected with SARS-CoV-2 can have persistent symptoms after acute illness, which affects their quality of life (QoL). Research and data about this topic in Latin American ambulatory patients are scarce. Materials and Methods: We conducted an observational, prospective, transversal, and analytical study. To measure QoL, we used a validated Spanish version of the MOS/RAND 36-Item Short Form Health Survey (SF-36). Results: We included 206 outpatients in the study. A total of 73.3% patients had persistence of one or more symptoms. The most frequent persistent symptoms were fatigue (36.9%), anxiety (26.2%), and headache (24.8%). No statistically significant difference in the SF-36 QoL scores and the frequency of persistent COVID-19 symptoms was found when comparing the ≤5 and >5 months groups, except for myalgia, which was less frequently observed in the >5 months group after COVID-19 (26.2% vs. 14.1%, p Conclusion: Most outpatients had persistent COVID-19 symptoms after infection. Persistence of symptoms was associated with poor MCS and PCS. It is important to follow-up not only patients discharged from the hospital after SARS-CoV-2 infection, but also those under ambulatory management to provide them with rehabilitation and psychological therapy to improve their QoL

Diagnostic Accuracy of the RDW for Predicting Death in COVID-19

Background and Objectives: An association between high red blood cell distribution width (RDW) and mortality has been found in several diseases, including infection and sepsis. Some studies have aimed at determining the association of elevated RDW with adverse prognosis in COVID-19, but its usefulness has not been well established. The objective of this study was to determine the accuracy of the RDW, measured at hospital admission and discharge, for predicting death in patients with COVID-19. Materials andMethods: An observational, retrospective, longitudinal, and analytical study was conducted in two different COVID-19 reference centers in the state of Guanajuato, Mexico. A total of 323 patients hospitalized by COVID-19 were included. Results: We found higher RDW levels at the time of hospital admission in the non-survivors group compared to levels in survivors (median = 13.6 vs. 13.0, p < 0.001). Final RDW levels were even higher in the deceased group when compared with those of survivors (median = 14.6 [IQR, 12.67–15.6] vs. 12.9 [IQR, 12.2–13.5], p < 0.001). For patients who died, an RDW > 14.5% was more common at the time of death than for patients who survived at the time of discharge (81 vs. 13 patients, p < 0.001; RR = 2.3, 95% CI 1.89–2.81). Conclusions: The RDW is an accessible and economical parameter that, together with other characteristics of the presentation and evolution of patients with COVID-19, can be helpful in determining the prognosis. An RDW that increases during hospitalization could be a more important mortality predictor than the RDW at hospital admission