A considerable proportion of patients with severe COVID-19 meet Sepsis-3 criteria and share common pathophysiological mechanisms of multiorgan injury with bacterial sepsis, in absence of secondary bacterial infections, a process characterized as “viral sepsis”. The intestinal barrier exerts a central role in the pathophysiological sequence of events that lead from SARS-CoV-2 infection to severe systemic complications. Accumulating evidence suggests that SARS-CoV-2 disrupts the integrity of the biological, mechanical and immunological gut barrier. Specifically, microbiota diversity and beneficial bacteria population are reduced, concurrently with overgrowth of pathogenic bacteria (dysbiosis). Enterocytes’ tight junctions (TJs) are disrupted, and the apoptotic death of intestinal epithelial cells is increased leading to increased gut permeability. In addition, mucosal CD4(+) and CD8(+) T cells, Th17 cells, neutrophils, dendritic cells and macrophages are activated, and T-regulatory cells are decreased, thus promoting an overactivated immune response, which further injures the intestinal epithelium. This dysfunctional gut barrier in SARS-CoV-2 infection permits the escape of luminal bacteria, fungi and endotoxin to normally sterile extraintestinal sites and the systemic circulation. Pre-existing gut barrier dysfunction and endotoxemia in patients with comorbidities including cardiovascular disease, obesity, diabetes and immunosuppression predisposes to aggravated endotoxemia. Bacterial and endotoxin translocation promote the systemic inflammation and immune activation, which characterize the SARS-CoV-2 induced “viral sepsis” syndrome associated with multisystemic complications of severe COVID-19.

Acinetobacter baumannii (AB) has evolved over the last decades as a major problem in carbapenem-resistant gram-negative nosocomial infections, associated with high mortality rates especially in the intensive care unit (ICU). Recent reports highlight the increasing prevalence of resistance to colistin, a last resort therapeutic option for carbapenem-resistant AB. We retrospectively evaluated the characteristics, treatment regimens and outcomes of twenty patients with pan-drug resistant (PDR) AB primary bacteremia hospitalized in the ICU of the University General Hospital of Patras, during a two-year period (October 2020–September 2022). The 28-day mortality reached 50%. Between survivors and non-survivors, no differences were found regarding age, gender, and Charlson comorbidity index (CCI). However, non-survivors had higher APACHE II scores and higher prevalence of septic shock and COVID-19 infection. A significantly higher percentage in the survivor group received Fosfomycin as part of the combination regimen. Inclusion of fosfomycin in the combination therapeutic regimen was associated with significantly better survival as compared to non-fosfomycin-containing regimens. In view of the increasing prevalence of PDR-AB infections in ICUs, its associated high rates of mortality and the lack of effective treatment options, the observed survival benefit with fosfomycin inclusion in the therapeutic regimen merits further validation in larger prospective studies.

Although coronavirus disease 2019 (COVID-19) is primarily associated with mild respiratory symptoms, a subset of patients may develop more complicated disease with systemic complications and multiple organ injury. The gastrointestinal tract may be directly infected by SARS-CoV-2 or secondarily affected by viremia and the release of inflammatory mediators that cause viral entry from the respiratory epithelium. Impaired intestinal barrier function in SARS-CoV-2 infection is a key factor leading to excessive microbial and endotoxin translocation, which triggers a strong systemic immune response and leads to the development of viral sepsis syndrome with severe sequelae. Multiple components of the gut immune system are affected, resulting in a diminished or dysfunctional gut immunological barrier. Antiviral peptides, inflammatory mediators, immune cell chemotaxis, and secretory immunoglobulins are important parameters that are negatively affected in SARS-CoV-2 infection. Mucosal CD4+ and CD8+ T cells, Th17 cells, neutrophils, dendritic cells, and macrophages are activated, and the number of regulatory T cells decreases, promoting an overactivated immune response with increased expression of type I and III interferons and other proinflammatory cytokines. The changes in the immunologic barrier could be promoted in part by a dysbiotic gut microbiota, through commensal-derived signals and metabolites. On the other hand, the proinflammatory intestinal environment could further compromise the integrity of the intestinal epithelium by promoting enterocyte apoptosis and disruption of tight junctions. This review summarizes the changes in the gut immunological barrier during SARS-CoV-2 infection and their prognostic potential.

Rationale: The introduction of immune-checkpoint inhibitors (ICPI) in recent years has changed the natural course of many neoplasms. However, patients receiving these medications may present immune-mediated adverse events; management includes temporary or permanent cessation of treatment and corticosteroids, occasionally combined with other immunomodulators. Such immunosuppression, however, also has numerous adverse events and even if it is effective in controlling toxicity, it delays immunotherapy reinitiation, as current evidence requires dose tapering to ≤10 mg prednisolone equivalent before rechallenge. Enteric-coated budesonide is a corticosteroid formulation acting primarily to the intestine and liver, as a result of its extensive first-pass hepatic metabolism.Patient concerns: A 76-year-old woman treated with ipilimumab for metastatic melanoma presented with abdominal pain, vomiting, and diarrhea for at least the previous 4 days. Laboratory tests, among others, revealed elevated aminotransferases and C-reactive protein. During hospitalization, the patient also developed fever.Diagnosis: The patient, after excluding alternative causes of aminotransferase elevation, was diagnosed with grade 3 ipilimumab-associated hepatotoxicity.Interventions: Budesonide monotherapy was administered; initial daily dose was 12 mg.Outcomes: Fever subsided after the first dose of budesonide. Aminotransferases returned to normal-near normal approximately 1 month after the first dose of budesonide. After this point, daily dose was reduced by 3 mg every 2 weeks, with no clinical or biochemical relapse.Conclusions: This case of ICPI hepatitis is, to our knowledge, the first in the literature managed with budesonide monotherapy. Therefore, budesonide may be a potentially attractive option for the management of ICPI-associated liver injury in cases where corticosteroid treatment is necessary due to its safety profile and the potential advantage of faster immunotherapy rechallenge in selected patients without requiring dose tapering, in contrast to systemically acting corticosteroids. Clinical trials should be conducted in the future in order to validate or refute these findings.Abbreviations: AIH = autoimmune hepatitis, ALT = alanine aminotransferase, AST = aspartate aminotransferase, CTLA-4 = cytotoxic T-lymphocyte antigen 4, ICPI = immune-checkpoint inhibitor, PD-1 = programmed cell death 1.

Background Mycobacterial infections can cause significant morbidity when cellular immunity is compromised. Patients with AIDS can be affected directly from infection or through mycobacterial IRIS, especially if they are previously untreated for HIV. Herein a case of tuberculous lymphadenitis is reported, which primarily responded to antimicrobials but complicated by IRIS and cat-scratch disease at a later course. Case presentation A 23-year-old man, intravenous drug user with untreated HIV and HCV infection presented with fever and painful cervical lymphadenopathy. Mycobacterium tuberculosis was isolated from PCR and culture of ultrasound-guided lymph node aspirate and a four-drug anti-TB regimen was subsequently administered, leading to complete resolution of clinical and laboratory abnormalities. Given the patient’s CD4 count (67 cells per mm3), antiretroviral treatment started seven weeks after TB treatment initiation. Within the first month of ART fever recurred along with cervical lymph node inflammation. Paradoxical IRIS was considered as the most probable diagnosis but workup expanded, revealing acute Bartonella infection. A posteriori, the patient remembered being scratched by a stray cat two weeks before his new symptoms started. Doxycycline and corticosteroid monotherapy failed to resolve symptoms, whereas a combination of doxycycline for 3 months and methylprednisolone with long-term tapering led to negative follow-up Bartonella antibodies and complete clinical and biochemical response, without recurrence. Conclusions Co-infection with TB and Bartonella presenting with lymphadenitis is unusual. Cat-scratch disease can be a rare clinical presentation of Bartonella infection in patients with AIDS, but coexistence of bartonellosis and paradoxical IRIS has never been reported before. However, physicians treating people living with HIV should be aware of this potential concurrence. Early testing for Bartonella infection could be offered in patients with TB and HIV co-infection in case of acute deterioration or partial response to treatment, especially if they have a history of cat exposure, since clinical picture can be indistinguishable.