A US-based national surveillance study for the susceptibility and epidemiology of Clostridioides difficile isolates with special reference to ridinilazole: 2020-2021.

We have previously reported on the susceptibility and epidemiology of Clostridioides difficile isolates from six geographically dispersed medical centers in the United States. This current survey was conducted with isolates collected in 2020-2021 from six geographically dispersed medical centers in the United States, with specific attention to susceptibility to ridinilazole as well as nine comparators. C. difficile isolates or stools from patients with C. difficile antibiotic-associated diarrhea were collected and referred to a central laboratory. After species confirmation of 300 isolates at the central laboratory, antibiotic susceptibilities were determined by the agar dilution method [M11-A9, Clinical and Laboratory Standards Institute (CLSI)] against the 10 agents. Ribotyping was performed by PCR capillary gel electrophoresis on all isolates. Ridinilazole had a minimum inhibitory concentration (MIC) 90 of 0.25 mcg/mL, and no isolate had an MIC greater than 0.5 mcg/mL. In comparison, fidaxomicin had an MIC 90 of 0.5 mcg/mL. The vancomycin MIC 90 was 2 mcg/mL with a 0.7% resistance rate [both CLSI and European Committee on Antimicrobial Susceptibility Testing (EUCAST) criteria]. The metronidazole MIC 90 was 1 mcg/mL, with none resistant by CLSI criteria, and a 0.3% resistance rate by EUCAST criteria. Among the 50 different ribotypes isolated in the survey, the most common ribotype was 014-020 (14.0%) followed by 106 (10.3%), 027 (10%), 002 (8%), and 078-126 (4.3%). Ridinilazole maintained activity against all ribotypes and all strains resistant to any other agent tested. Ridinilazole showed excellent in vitro activity against C. difficile isolates collected between 2020 and 2021 in the United States, independent of ribotype.

Creatine supplementation: effects on urinary excretion and anaerobic performance.

AIM: The aim of the present study is to investigate Urinary creatine (URCR) and urinary creatinine (URCRN) response to CR supplementation in conjunction with exercise performance. METHODS: Twenty-one sprint trained males were randomly divided into 3 groups. Each group followed a different CR dosage (10 g, 25 g and 35 g x day(-1) for 4 days) and placebo (Pl) in the 1(st) and 2(nd) week, respectively. A double-blind design was used. Subjects' urine was collected every 24 hours during the entire period of supplementation (SP). All groups, at the end of each SP performed 3 times the Anaerobic Wingate Test (AWT) with 6 min active recovery (60 rpm) on a cycle ergometer. RESULTS: Significantly (p<0.01) higher peak and mean power values were produced during the CR compared to Pl condition. A significant correlation (r=0.7, p<0.05) was also observed between peak power improvement (PPI) and URCR for the 3 groups. No such relationship was found between URCRN. Across all groups, URCR and URCRN increased significantly following ingestion compared with Pl (p<0.001). URCR post- supplementation presented a 7.4 fold, 36 fold and 21 fold increase for 10 g, 25 g and 35 g dose respectively, whilst URCRN presented a mean 2.4 fold increase for all different doses, which clearly shows the magnitude of sensitivity of these indices to CR supplementation. A strong correlation (r=0.95, p<0.01) observed between dose of CR ingestion and mean URCR (MRUCR) with prediction formula: CR = -0.936 + (5.613 x MRUCR) (SEE=3.5). CONCLUSION: URCR was an effective measure of each CR dosage administered as well as of the excretion pattern that each group followed throughout the SP. Furthermore the strong relationship of URCR and PPI could be particularly useful for monitoring and optimising CR loading in athletic populations.