Multispecies probiotics are effective in IBS patients and induce the alterations in the composition of intestinal microbiota.

Directed evolution can be a powerful tool to predict antibiotic resistance. Resistance involves the accumulation of mutations beneficial to the pathogen while maintaining residue interactions and core packing that are critical for preserving function. The constraint of maintaining stability, while increasing activity, drastically reduces the number of possible mutational combination pathways. To test this theory, TEM-1 beta-lactamase was evolved using a hypermutator E. coli-based directed evolution technique with cefotaxime selection. The selected mutants were compared to two previous directed evolution studies and a database of clinical isolates. In all cases, evolution resulted in the generation of the E104K/M182T/G238S combination of mutations ( approximately 500-fold increased resistance), which is equivalent to clinical isolate TEM-52. The structure of TEM-52 was determined to 2.4 A. G238S widens access to the active site by 2.8 A whereas E104K stabilizes the reorganized topology. The M182T mutation is located 17 A from the active site and appears to be a global suppressor mutation that acts to stabilize the new enzyme structure. Our results demonstrate that directed evolution coupled with structural analysis can be used to predict future mutations that lead to increased antibiotic resistance.

Background The impact of sarcopenia on clinical outcomes of coronavirus disease 2019 (COVID-19) is not clearly determined yet. We aimed to investigate the association between baseline sarcopenia and clinical outcomes in patients with COVID-19. Methods All hospitalized adult patients with COVID-19 who had baseline chest computed tomography (CT) scans at a Korean university hospital from February 2020 to May 2020 were included. The main outcome was time from hospital admission to discharge. Death was considered as a competing risk for discharge. Baseline skeletal muscle cross-sectional area at the level of the 12th thoracic vertebra was measured from chest CT scans. The lowest quartile of skeletal muscle index (skeletal muscle cross-sectional area divided by height-squared) was defined as sarcopenia. Results Of 121 patients (median age, 62 years; 44 men; 29 sarcopenic), 7 patients died and 86 patients were discharged during the 60-day follow-up. Patients with sarcopenia showed a longer time to discharge (median, 55 vs. 28 days; p<0.001) and a higher incidence of death (17.2% vs. 2.2%; p=0.004) than those without sarcopenia. Baseline sarcopenia was an independent predictor of delayed hospital discharge (adjusted hazard ratio [aHR], 0.47; 95% CI, 0.23-0.96), but was not independently associated with mortality in patients with COVID-19 (aHR, 3.80; 95% CI, 0.48-30.26). The association between baseline sarcopenia and delayed hospital discharge was consistent in subgroups stratified by age, sex, comorbidities, and severity of COVID-19. Conclusion Baseline sarcopenia was independently associated with prolonged hospital stay in patients with COVID-19. Sarcopenia could be a prognostic marker in COVID-19.

Liver cirrhosis and hepatocellular carcinoma (HCC) are serious late complications that can occur after the Fontan procedure. This study aimed to investigate the cumulative incidence of cirrhosis and HCC and to identify specific features distinguishing HCC from benign arterial-phase hyperenhancing (APHE) nodules that developed after the Fontan operation. We retrospectively enrolled 313 post-Fontan patients who had been followed for more than 5 years and had undergone ultrasound or computed tomography (CT) of the liver between January 2000 and August 2018. Cirrhosis was diagnosed radiologically. The estimated cumulative incidence rates of cirrhosis at 5, 10, 20, and 30 years after the Fontan operation were 1.3%, 9.2%, 56.6%, and 97.9%, respectively. Multiphasic CT revealed that 18 patients had APHE nodules that were ≥1 cm in size and showed washout in the portal venous phase (PVP)/delayed phase, which met current noninvasive HCC diagnosis criteria. Among them, only seven patients (38.9%, 7/18) were diagnosed with HCC. After cirrhosis developed, the annual incidence of HCC was 1.04%. The appearance of washout in the PVP (p = 0.006), long time elapsed since the initial Fontan operation (p = 0.04), large nodule size (p = 0.03), and elevated serum α-fetoprotein (AFP) level (p < 0.001) were significantly associated with HCC. In conclusion, cirrhosis is a frequent late complication after Fontan operation, especially after 10 years, and HCC is not a rare complication after cirrhosis development. Diagnosis of HCC should not be based solely on the current imaging criteria, and washout on PVP and clinical features might be helpful to differentiate HCC nodules from benign APHE nodules.

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