The rapid scientific interest in gut microbiota (GM) has coincided with a global increase in the prevalence of infectious and non-infectivous liver diseases. GM, which is also called “the new virtual metabolic organ”, makes axis with a number of extraintestinal organs, such as kidneys, brain, cardiovascular, and the bone system. The gut-liver axis has attracted greater attention in recent years. GM communication is bi-directional and involves endocrine and immunological mechanisms. In this way, gut-dysbiosis and composition of “ancient” microbiota could be linked to pathogenesis of numerous chronic liver diseases such as chronic hepatitis B (CHB), chronic hepatitis C (CHC), alcoholic liver disease (ALD), non-alcoholic fatty liver disease (NAFLD), non-alcoholic steatohepatitis (NASH), development of liver cirrhosis, and hepatocellular carcinoma (HCC). In this paper, we discuss the current evidence supporting a GM role in the management of different chronic liver diseases and potential new therapeutic GM targets, like fecal transplantation, antibiotics, probiotics, prebiotics, and symbiotics. We conclude that population-level shifts in GM could play a regulatory role in the gut-liver axis and, consequently, etiopathogenesis of chronic liver diseases. This could have a positive impact on future therapeutic strategies.

Hospital-acquired infections (HAIs) are a global public health concern. As the COVID-19 pandemic continues, its contribution to mortality and antimicrobial resistance (AMR) grows, particularly in intensive care units (ICUs). A two-year retrospective study from April 2019–April 2021 was conducted in an adult ICU at the Hospital for Infectious and Tropical Diseases, Belgrade, Serbia to assess causative agents of HAIs and AMR rates, with the COVID-19 pandemic ensuing halfway through the study. Resistance rates >80% were observed for the majority of tested antimicrobials. In COVID-19 patients, Acinetobacter spp. was the dominant cause of HAIs and more frequently isolated than in non-COVID-19 patients. (67 vs. 18, p = 0.001). Also, resistance was higher for imipenem (56.8% vs. 24.5%, p < 0.001), meropenem (61.1% vs. 24.3%, p < 0.001) and ciprofloxacin (59.5% vs. 36.9%, p = 0.04). AMR rates were aggregated with findings from our previous study to identify resistance trends and establish empiric treatment recommendations. The increased presence of Acinetobacter spp. and a positive trend in Klebsiella spp. resistance to fluoroquinolones (R2 = 0.980, p = 0.01) and carbapenems (R2 = 0.963, p = 0.02) could have contributed to alarming resistance rates across bloodstream infections (BSIs), pneumonia (PN), and urinary tract infections (UTIs). Exceptions were vancomycin (16.0%) and linezolid (2.6%) in BSIs; tigecycline (14.3%) and colistin (0%) in PNs; and colistin (12.0%) and linezolid (0%) in UTIs. COVID-19 has changed the landscape of HAIs in our ICUs. Approval of new drugs and rigorous surveillance is urgently needed.

Purpose The purpose of this study is to determine heart rate (HR) recovery after maximal test in elite athletes who compete in high dynamic, high static, and in mixed sport disciplines; to assess differences in HR recovery between these groups of athletes; and to measure the association of HR index (HRI) with heart adaptation variables to determine whether these values were correlated with the type of exercise. Methods One hundred and ninety-four elite athletes were divided into three groups according to the predominant type of exercise performed: endurance (n = 40), strength-sprinter (n = 36), and ball-game players (n = 118). They performed maximal cardiopulmonary exercise testing on a treadmill and were subjected to echocardiography. The rate of decline (HR recovery) was calculated as the difference between maximum and recovery HRs (HRrec1 and HRrec3). The HRI was calculated as HRmax – 1-min post-exercise HR (HRrec1). Results The most significant correlation of HRI was with posterior wall diameter and left ventricular (LV) mass index (r = 0.43 and r = 0.51; p = 0.012 and p = 0.003, respectively). LV mass index [Beta (B) = 0.354, p = 0.001] was an independent predictor of HRI and HRrec1. HRI may be an effective tool for discrimination of physiological and “gray zone” LV hypertrophy, with area under the curve of 0.545 (95% CI = 0.421–0.669, p = 0.0432). HRI displayed a sensitivity of 50% and specificity of 52.2% at the optimal cut-off value of 23.5. Conclusion HR recovery pattern, especially HRI, may offer a timely and efficient tool to identify athletes with autonomous nervous system adaptive changes.

Changes in gut microbiota influence both the gut and liver, which are strictly connected by the so-called “gut–liver axis”. The gut microbiota acts as a major determinant of this relationship in the onset and clinical course of liver diseases. According to the results of several studies, gut dysbiosis is linked to viral hepatitis, mainly hepatitis C virus and hepatitis B virus infection. Gut bacteria-derived metabolites and cellular components are key molecules that affect liver function and modulate the pathology of viral hepatitis. Recent studies showed that the gut microbiota produces various molecules, such as peptidoglycans, lipopolysaccharides, DNA, lipoteichoic acid, indole-derivatives, bile acids, and trimethylamine, which are translocated to the liver and interact with liver immune cells causing pathological effects. Therefore, the existence of crosstalk between the gut microbiota and the liver and its implications on host health and pathologic status are essential factors impacting the etiology and therapeutic approach. Concrete mechanisms behind the pathogenic role of gut-derived components on the pathogenesis of viral hepatitis remain unclear and not understood. In this review, we discuss the current findings of research on the bidirectional relationship of the components of gut microbiota and the progression of liver diseases and viral hepatitis and vice versa . Moreover, this paper highlights the current therapeutic and preventive strategies, such as fecal transplantation, used to restore the gut microbiota composition and so improve host health.

Background: The global epidemic of nosocomial diarrhea caused by Clostridioides (Clostridium) difficile started in 2000, with high mortality rates and emergence of a new hypervirulent strain NAP1/BI/027. The aim of this study was to assess the presence of ribotype 027 and other C. difficile ribotypes in a Serbian University Hospital, compare the temporal variability of ribotypes 3 years apart, as well as to compare clinical, demographic and laboratory characteristics and disease outcome among patients infected with 027 and non-027 ribotype. This was a prospective observational cohort study addressing 4-month intervals during 2014/2015 and 2017/2018. Results: Ribotyping was performed in 64 non-duplicate C. difficile strains. Ribotype 027 was the most prevalent, and was detected in 53 (82.8%) patients (43/45 and 10/19 patients in 2014-2015 and 2017/2018, respectively). Other detected ribotypes were 001/072 in 4 (6.3%), 002 in 4 (6.3%), 014/020 in 2 (3.1%) and 176 in 1 (1.5%) patient. The percentage of the patients infected with ribotype 027 significantly decreased during the 3-year period, from 95.6 to 52.6% (p < 0.001). Ribotype 027 infection was associated with fluoroquinolone treatment more frequently than infection with other ribotypes [33 (62.3%) vs. 2 (18.2%), p = 0.010)]. A severe C. difficile infection was diagnosed more often in patients with the detected ribotype 027 compared to those infected with non-027 ribotypes (p = 0.006). No significant difference in the mortality and recurrence rates was found between the patients infected with ribotype 027 and those infected with other ribotypes [10/53 (18.8%) vs. 2/11 (18.2%), p = 0.708, and 10/35 (28.6%) vs. 0/2 (0%), p = 1.000, respectively]. Conclusion: Clostridium difficile ribotype 027 was the most prevalent ribotype among patients in a large Serbian hospital, but there is a clear decreasing trend.

In late December 2019, in the city of Wuhan, in China, the appearance of unknown viral pneumonia was recorded in a large number of patients. The cause of this infection was soon discovered - a new coronavirus, called SARS-CoV-2, due to its genetic similarity to the virus that causes severe acute respiratory syndrome (SARS-CoV). The infection then spread rapidly to other continents, and the pandemic is still ongoing. The clinical presentation varies from the asymptomatic form to symptoms of upper respiratory tract infection, and finally to pneumonia and acute respiratory distress syndrome (ARDS). The elderly, immunocompromised patients, and patients suffering from chronic, internal medicine diseases are at risk of the severe form of the COVID-19 disease. The virus enters cells via angiotensin converting enzyme 2 (ACE2) receptors, which are present in practically all tissues in the body. In addition to interstitial pneumonia, pathological changes are also found in other organ systems. The first case in Serbia was recorded on March 6, 2020. A large number of patients required the engagement of health workers of all profiles as well as the introduction of a large number of health institutions into the COVID system. The emergence of a new virus necessitated a new antiviral drug. Based on previous experience with the SARS-CoV virus, previously known antiviral drugs have been used, with varying degrees of success. The therapy changed in accordance with new knowledge, and since the beginning of the epidemic in Serbia, the National Protocol of the Republic of Serbia for the Treatment of the COVID-19 Infection has been established, which has kept apace with the recommendations of the world's leading institutions. The most significant event during the pandemic was the development of the vaccine against COVID-19, with vaccination in Serbia beginning in December 2020. How quickly the epidemic will end depends directly on the speed and efficiency of vaccination, along with other epidemiological measures.

Introduction Coronavirus disease of 2019 (COVID-19) is a global health problem. The impact of chronic liver diseases on the course and outcome of COVID-19 is still the subject of research. The aim of this study was to show the characteristics of COVID-19 patients with chronic liver diseases, and to establish the risk factors for unfavourable outcome. Methods A retrospective observational study was conducted at the Infectious Disease Clinic in Belgrade, Serbia, and included 80 patients with chronic liver diseases and COVID-19 within a time frame of two years (between 15 March 2020 and 15 March 2022). Characteristics of the affected persons, as well as the risk factors for a fatal outcome, were analyzed. Results Of the 80 subjects in the study, 23.8% had chronic viral hepatitis, 12.5% autoimmune liver diseases and alcoholic liver disease respectively, 30% had non-alcoholic fatty liver disease, while 11.2% had chronic liver diseases of unknown aetiology. A total of 33.7% had cirrhosis, 6.3% hepatocellular carcinoma and 5% had liver transplants. A total of 92.5% of respondents had pneumonia (21.2% were critically ill). A deterioration of chronic liver disease was registered among 33.7% of patients, and decompensation in 3.8%; 76.3% patients recovered, while 23.7% had a lethal outcome. Risk factors for lethal outcome by univariate analysis were: alcoholic liver disease, cirrhosis, increased transaminases values prior to COVID-19, malignancy, severe pneumonia and dyspnea. In a multivariate analysis, the presence of liver cirrhosis (OR = 69.1, p = 0.001) and severe pneumonia (OR = 22.3, p = 0.006) remained independently predictive for lethal outcome. Conclusion These findings will help with the evaluation of COVID-19 patients who have chronic liver diseases and will improve their risk stratification.

Background We investigated the therapeutic response of tocilizumab (TCZ) therapy in patients with coronavirus disease 2019 (COVID-19) pneumonia. Methods This observational retrospective study included 205 patients with confirmed COVID-19 pneumonia with SpO2˂93% and a markedly increased level of at least two biomarkers of inflammation. The TCZ was given in combination with corticosteroids. Clinical and laboratory results were analyzed and compared before TCZ therapy and 7 d after. Results The mean value of C-reactive protein (CRP) was significantly lower (p=0.001) on the seventh day after administration of TCZ compared with before (10.7 and 173.6 mg/L, respectively). Only in 9/205 (4.3%) patients, the CRP level did not decrease during the week-long period, and this was related to disease progression. The mean level of interleukin-6 before TCZ administration was 88±113 pg/mL, while after it was 32.7±21.7 pg/mL (p=0.01). After 7 d of TCZ therapy, almost 50% of patients who needed high-flow oxygen or ventilation support started to receive low-flow oxygen, while 73/205 (35.6%) patients who received low-flow oxygen before TCZ administration did not receive further oxygen support anymore (p=0.001). Although they received TCZ treatment, 38/205 (18.5%) severely sick patients died. Conclusions Tocilizumab improves clinical outcomes in hospitalized COVID-19 patients. These advantages were evident independent of the patient's comorbidities and were in addition to the advantages of systemic corticosteroids. In COVID-19 patients at risk of cytokine storms, TCZ appears to be an effective therapy choice.