Gut Microbiota and Infectious Complications in Advanced Chronic Liver Disease: Focus on Spontaneous Bacterial Peritonitis.

Liver cirrhosis is a chronic disease that can be complicated by episodes of decompensation such as variceal bleeding, hepatic encephalopathy, ascites, and jaundice, with subsequent increased mortality. Infections are also among the most common complications in cirrhotic patients, mostly due to a defect in immunosurveillance. Among them, one of the most frequent is spontaneous bacterial peritonitis (SBP), defined as the primary infection of ascitic fluid without other abdominal foci. SBP is mainly induced by Gram-negative bacteria living in the intestinal tract, and translocating through the intestinal barrier, which in cirrhotic patients is defective and more permeable. Moreover, in cirrhotic patients, the intestinal microbiota shows an altered composition, poor in beneficial elements and enriched in potentially pathogenic ones. This condition further promotes the development of leaky gut and increases the risk of SBP. The first-line treatment of SBP is antibiotic therapy; however, the antibiotics used have a broad spectrum of action and may adversely affect the composition of the gut microbiota, worsening dysbiosis. For this reason, the future goal is to use new therapeutic agents that act primarily on the gut microbiota, selectively modulating it, or on the intestinal barrier, reducing its permeability. In this review, we aim to describe the reciprocal relationship between gut microbiota and SBP, focusing on pathogenetic aspects but also on new future therapies.

COVID-19 as a trigger of irritable bowel syndrome: A review of potential mechanisms.

In December 2019 a novel coronavirus disease 2019 (COVID-19), caused by the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), started spreading from Wuhan city of Chinese Hubei province and rapidly became a global pandemic. Clinical symptoms of the disease range from paucisymptomatic disease to a much more severe disease. Typical symptoms of the initial phase include fever and cough, with possible progression to acute respiratory distress syndrome. Gastrointestinal manifestations such as diarrhoea, vomiting and abdominal pain are reported in a considerable number of affected individuals and may be due to the SARS-CoV-2 tropism for the peptidase angiotensin receptor 2. The intestinal homeostasis and microenvironment appear to play a major role in the pathogenesis of COVID-19 and in the enhancement of the systemic inflammatory responses. Long-term consequences of COVID-19 include respiratory disturbances and other disabling manifestations, such as fatigue and psychological impairment. To date, there is a paucity of data on the gastrointestinal sequelae of SARS-CoV-2 infection. Since COVID-19 can directly or indirectly affect the gut physiology in different ways, it is plausible that functional bowel diseases may occur after the recovery because of potential pathophysiological alterations (dysbiosis, disruption of the intestinal barrier, mucosal microinflammation, post-infectious states, immune dysregulation and psychological stress). In this review we speculate that COVID-19 can trigger irritable bowel syndrome and we discuss the potential mechanisms.

Improved gut microbiota features after the resolution of SARS­CoV­2 infection.

BACKGROUND: The severe acute respiratory syndrome coronavirus 2 (SARS­CoV­2) has a tropism for the gastrointestinal tract and several studies have shown an alteration of the gut microbiota in hospitalized infected patients. However, long-term data on microbiota changes after recovery are lacking. METHODS: We enrolled 30 patients hospitalized for SARS­CoV­2-related pneumonia. Their gut microbiota was analyzed within 48 h from the admission and compared with (1) that of other patients admitted for suspected bacterial pneumonia (control group) (2) that obtained from the same subject 6 months after nasopharyngeal swab negativization. RESULTS: Gut microbiota alpha-diversity increased 6 months after the resolution of SARS-CoV-2 infection. Bacteroidetes relative abundance was higher (≈ 36.8%) in patients with SARS-CoV-2, and declined to 18.7% when SARS-CoV-2 infection resolved (p = 0.004). Conversely, Firmicutes were prevalent (≈ 75%) in controls and in samples collected after SARS-CoV-2 infection resolution (p = 0.001). Ruminococcaceae, Lachnospiraceae and Blautia increased after SARS-CoV-2 infection resolution, rebalancing the gut microbiota composition. CONCLUSION: SARS-CoV-2 infection is associated with changes in the gut microbiome, which tend to be reversed in long-term period.

Italian association for the study of the liver position statement on SARS-CoV2 vaccination.

The vaccination campaign against Sars-CoV-2 commenced in Italy at the end of December 2020. The first ones to receive the immunization against the virus were the health workers and the residents of nursing homes, following which the vaccine would be available for the entire population, beginning with the most vulnerable individuals. SARS-CoV2 vaccines have been demonstrated to be safe for the general population, although no data for patients with liver diseases or those having undergone liver transplantation are available so far. The present position statement AISF is an attempt to suggest, based on the published data on the impact of Sars-Cov-2 infection in patients with chronic liver disease, a possible priority for vaccination for this category of patients.

Nasopharyngeal Microbiota Profiling of SARS-CoV-2 Infected Patients.

We analyzed the bacterial communities of the nasopharynx in 40 SARS-CoV-2 infected and uninfected patients. All infected patients had a mild COVID-19 disease. We did not find statistically significant differences in either bacterial richness and diversity or composition. These findings suggest a nasopharyngeal microbiota at least early resilient to SARS-CoV-2 infection.

Assessing the impact of COVID-19 on the management of patients with liver diseases: A national survey by the Italian association for the study of the Liver.

BACKGROUND: The COVID-19 pandemic had a huge impact on national and regional health systems. The impact of SARS-CoV-2 on the quality of care for patients with liver disease is still unknown. AIMS: The Italian Association for the Study of the Liver (AISF) conducted a survey to assess the impact of SARS-CoV-2 on hepatology units activities in Italy. METHODS: A prospective web-based survey was proposed to all AISF active members. The survey was available online from April 8 2020, to May 3 2020, (lockdown phase in Italy). RESULTS: 194 AISF members answered the questionnaire, most of whom were specialists in Gastroenterology (41%) or Internal Medicine (28%), and worked in Northern Italy (51%). 26% of hepatology wards had been converted into COVID-19 wards, and 33% had bed reductions. All hepatological activities, including the management of patients with decompensated liver disease, liver transplant and HCC had been significantly reduced/stopped. The number of physicians answering that their practices had not been modified ranged between 0.6% (for chronic hepatitis) to 47% (for the execution of paracentesis). The recorded answers were consistent among different regions, and did not show any north-south gradient CONCLUSION: COVID-19 outbreak significantly impacted on hepatological clinical activity. This survey can serve as a basis to compare the impact of future measures aimed at delivering an acceptable level of liver care during a national pandemic or crisis.

Liver involvement is not associated with mortality: results from a large cohort of SARS-CoV-2-positive patients.

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is frequently associated with liver test abnormalities. AIMS: To describe the evolution of liver involvement during SARS-CoV-2 infection and its effect on clinical course and mortality. METHODS: Data of 515 SARS-CoV-2-positive patients were collected at baseline and during follow-up, last evaluation or death. Stratification based on need for hospitalisation, severe disease and admission to intensive care unit (ICU) was performed. The association between liver test abnormalities (baseline and peak values) and ICU admission or death was also explored. RESULTS: Liver test abnormalities were found in 161 (31.3%) patients. Aspartate aminotransferase (AST), alanine aminotransferase (ALT) and gamma glutamyl transferase (GGT) were increased in 20.4%, 19% and 13.6% of patients, respectively. Baseline liver test abnormalities were associated with increased risk of ICU admission (OR 2.19 [95% CI 1.24-3.89], P = 0.007) but not with mortality (OR 0.84 [95% CI 0.49-1.41], P = 0.51). Alkaline phosphatase (ALP) peak values were correlated with risk of death (OR 1.007 [95% CI 1.002-1.01], P = 0.005) along with age, multiple comorbidities, acute respiratory distress syndrome, ICU admission and C-reactive protein. Alterations of liver tests worsened within 15 days of hospitalisation; however, in patients with the longest median follow-up, the prevalence of liver test alterations decreased over time, returning to around baseline levels. CONCLUSIONS: In SARS-CoV-2-positive patients without pre-existing severe chronic liver disease, baseline liver test abnormalities are associated with the risk of ICU admission and tend to normalise over time. The ALP peak value may be predictive of a worse prognosis.