Paramount efforts worldwide are seeking to increase understanding of the basic virology of SARS-CoV-2, characterize the spectrum of complications associated with COVID-19, and develop vaccines that can protect from new and recurrent infections with SARS-CoV-2. While we continue learning about this new virus, it is clear that 1) the virus is spread via the respiratory route, primarily by droplets and contact with contaminated surfaces and fomites, as well as by aerosol formation during invasive respiratory procedures; 2) the airborne route is still controversial; and 3) that those infected can spread the virus without necessarily developing COVID-19 (ie, asymptomatic). With the number of SARS-CoV-2 infections increasing globally, the possibility of co-infections and/or co-morbidities is becoming more concerning. Co-infection with Human Immunodeficiency Virus (HIV) is one such example of polyparasitism of interest. This military-themed comparative review of SARS-CoV-2 and HIV details their virology and describes them figuratively as separate enemy armies. HIV, an old enemy dug into trenches in individuals already infected, and SARS-CoV-2 the new army, attempting to attack and capture territories, tissues and organs, in order to provide resources for their expansion. This analogy serves to aid in discussion of three main areas of focus and draw attention to how these viruses may cooperate to gain the upper hand in securing a host. Here we compare their target, the key receptors found on those tissues, viral lifecycles and tactics for immune response surveillance. The last focus is on the immune response to infection, addressing similarities in cytokines released. While the majority of HIV cases can be successfully managed with antiretroviral therapy nowadays, treatments for SARS-CoV-2 are still undergoing research given the novelty of this army.

Background: Primary sclerosing cholangitis-associated UC (PSC-UC) carries excess colorectal neoplasia despite often mild-appearing endoscopy, implicating persistent microscopic inflammation and microbiota–bile acid (BA) dysfunction. Objective: To test whether PSC-UC neoplasia is driven by transferable microbiota-mediated inflammation linked to secondary BA loss. Design: Surveillance colonoscopies (2012–2022) from PSC-UC (n=251) and UC-only (n=8839) were compared for segmental endoscopic/histological activity and dysplasia. We generated multidrug resistance protein 2 (MDR2) ^−/− × interleukin (IL)-10 ^−/− double-knockout (DKO) mice and used germ-free (GF) derivation, faecal microbiota transplantation (FMT), antibiotic conditioning and cohousing with shotgun metagenomics and liquid chromatography–tandem mass spectrometry BA profiling. Results: PSC-UC showed greater inflammatory activity and a right-shifted dysplasia burden versus UC-only. Under specific-pathogen-free conditions, DKO mice developed early right-predominant colitis and multifocal dysplasia progressing with age. DKO communities were depleted of 7α-dehydroxylation capacity with near absence of deoxycholic and lithocholic acids and no enrichment of canonical bacterial genotoxins. GF DKO mice were protected, whereas live DKO donor FMT reinstated severe colitis and dysplasia; sterile-filtered stool supernatant was inactive. IL-10 ^−/− donor FMT or cohousing attenuated colitis and increased recipient secondary BA, whereas wild-type/MDR2 ^−/− donor transfers were non-colitogenic. In GF DKO mice, direct deoxycholic acid repletion caused hepatotoxicity. Conclusion: PSC-UC neoplasia associates with transmissible microbiota-dependent inflammation and secondary BA deficiency. Controlled restoration of BA-transforming microbial functions, rather than indiscriminate secondary BA replacement, is a rational translational direction.

The SARS-CoV-2 pandemic provides a natural opportunity for the collision of coronavirus disease-2019 (COVID-19) with chronic infections, which place numerous individuals at high risk of severe COVID-19. Infection with Human Immunodeficiency Virus (HIV), a global epidemic, remains a major public health concern. Whether prior HIV+ status exacerbates COVID-19 warrants investigation. Herein, we characterized the impact of SARS-CoV-2 in human bronchial epithelial cells (HBECs) previously exposed to HIV. We optimized the air-liquid interface (ALI) cell culture technique to allow for challenges with HIV at the basolateral cell surface and SARS-CoV-2 spike protein on the apical surface, followed by genetic analyses for cellular stress/toxicity and innate/adaptive immune responses. Our results suggest that the IL-10 pathway was consistently activated in HBECs treated with spike, HIV, or a combination. Recombinant spike protein elicited COVID-19 cytokine storms while HIV activated different signaling pathways. HIV-treated HBECs could no longer activate NF-kB, pro-inflammatory TRAF-6 ubiquitination nor RIP1 signaling. Combinations of HIV and SARS-CoV-2 spike increased gene expression for activation of endoplasmic reticulum-phagosome pathway and downregulated non-canonical NF-kB pathways that are key in functional regulatory T cells and RNA Polymerase II transcription. Our in vitro studies suggest that prior HIV infection may not exacerbate COVID-19. Further in vivo studies are warranted to advance this field.

Chronic infections with Pseudomonas aeruginosa are a major contributor of lung decline in persons with cystic fibrosis (pwCF). P. aeruginosa establishes life-long infections in the CF airway by utilizing various adaptation strategies to persist, including altering the expression of metabolic genes to acquire nutrients that are abundant in the CF airway. Glycerol, which is readily available in the airway, is imported and metabolized by genes in the glp regulon, which is under the control of the GlpR repressor. Previously, it has been shown that the loss of GlpR results in increased biofilm development in a CF-adapted isolate of P. aeruginosa compared to a wound isolate. Based on the increased biofilm phenotype previously observed and because biofilms are associated with reduced antibiotic susceptibility, we questioned whether GlpR plays a role in mediating antibiotic susceptibility of P. aeruginosa . In this report, we show that loss of GlpR reduces tobramycin susceptibility of a CF-adapted isolate in synthetic sputum and in airway epithelial cell and Drosophila melanogaster colonization models. Furthermore, transcriptomics analysis revealed that CF-adapted mutants of glpR overexpress genes involved in multidrug resistance and chronic infection phenotypes such as alginate. In summary, our study illustrates that the activation of the glycerol ( glp ) regulon may promote P. aeruginosa persistence in the CF airway.