Multicenter evaluation of the Selux Next-Generation Phenotyping antimicrobial susceptibility testing system.

The Selux Next-Generation Phenotyping (NGP) system (Charlestown, MA) is a new antimicrobial susceptibility testing system that utilizes two sequential assays performed on all wells of doubling dilution series to determine MICs. A multicenter evaluation of the performance of the Selux NGP system compared with reference broth microdilution was conducted following FDA recommendations and using FDA-defined breakpoints. A total of 2,488 clinical and challenge isolates were included; gram-negative isolates were tested against 24 antimicrobials, and gram-positive isolates were tested against 15 antimicrobials. Data is provided for all organism-antimicrobial combinations evaluated, including those that did and did not meet FDA performance requirements. Overall very major error and major error rates were less than 1% (31/3,805 and 107/15,606, respectively), essential agreement and categorical agreement were >95%, reproducibility was ≥95%, and the average time-to-result (from time of assay start to time of MIC result) was 5.65 hours.

Effects of Magnesium Supplementation on Muscle Soreness and Performance.

ABSTRACT: Reno, AM, Green, M, Killen, LG, O'Neal, EK, Pritchett, K, and Hanson, Z. Effects of magnesium supplementation on muscle soreness and performance. J Strength Cond Res 36(8): 2198-2203, 2022-This double-blind, between-group study examined effects of magnesium (Mg) supplementation (350 mg·d -1 , 10 days) on muscle soreness and performance. College-aged male ( n = 9) and female ( n = 13) subjects completed baseline and posttreatment eccentric bench press sessions inducing fatigue/soreness followed by performance sessions (total volume and repetitions to failure [RTF] [65, 75, and 85% of 1 repetition maximum]) 48 hours later with perceptual measures. Subjects estimated soreness using a Delayed Onset of Muscle Soreness scale by striking a vertical line on a 6-cm horizontal line (at 24, 36, and 48 hours post trial) from 0-no soreness to 6-intolerable soreness. Results are presented as means ± SD (alpha ≤0.05). Mg significantly reduced (∼1-2 units lower on a 6-point scale) muscle soreness from the baseline eccentric to postintervention trial 24, 36, and 48 hours with no significant change for placebo (Pla) group. Performance approached significance for total RTF ( p = 0.06) and 65 and 75% RTF ( p = 0.08) (Mg vs. Pla). Perceptual responses for session rating of perceived exertion and acute rating of perceived exertion were significant for Mg (5.1 ± 2.4 to 4.1 ± 2.0) vs. Pla (5.0 ± 1.8 to 5.5 ± 1.6). Perceived recovery after supplementation was improved vs. baseline for Mg (5.4 ± 2.2 to 7.5 ± 2.3) but not for Pla (6.2 ± 2.4 to 7.2 ± 3.3). Results show significantly reduced muscle soreness, session rating of perceived exertion, acute rating of perceived exertion, and improved perceived recovery after Mg (vs. Pla) supplementation and some evidence for positive performance impact.

Cranial Mandibular Fibrosis Syndrome in Adult Farmed Rainbow Trout Oncorhynchus mykiss.

An unusual condition affecting market size rainbow trout was investigated. This condition was prevalent for several years at low levels but affected a large proportion of stock during 2018 and 2019. Chronic fibrosis affecting cranial tissues and the jaw was observed in samples collected in 2018. A larger sampling was then conducted in 2019 to investigate the presence of an infectious agent(s). An extensive inflammatory response in the mandibular region was the main finding, however infectious agents in the lesions were not identified through classical virology and bacteriology analysis. Tetracapsuloides bryosalmonae infection, calcinosis, and a Gram-positive bacterial infection of a single fish cardiac tissue was observed, however, a correlation of these pathologies and the cranial mandibular fibrosis (CMF) syndrome was not established. The gene expression of a panel of 16 immune-related genes was studied. Among these, tgf-b, sIgM, il11, hspa, and the antimicrobial peptides lys and cath1 were up-regulated in jaw sections of CMF-affected fish, showing a strong positive correlation with the severity of the lesions. Idiopathic chronic fibrosis with the activation of the Tfg-B pathway and local hyper-immunoglobulaemia was therefore diagnosed. Initiating factors and causative agent(s) (biotic or abiotic) of CMF remain, at present, unclear.

Effects of Three Modest Levels of Proximal Loading on Marathon Pace Running Economy.

This study examined the effect of modest increases in proximal body mass on running economy expressed as metabolic cost (MC). External loads of 1.6 (L), 2.4 (M), and 3.2 kg (H) were added to the anterior and posterior torso region of male (n = 18) and female (n = 18) runners using a double-layered compression garment with gel inserts. MC was evaluated using stoichiometry equations of data collected via indirect calorimetry. Data was collected during four, 5-min running bouts at marathon pace for the 3 load levels and an unloaded state (CON). When data from both sexes were combined, MC for CON (13.2 ± 2.7) was lower (p < 0.05) versus L (13.5 ± 2.6), M (13.6 ± 2.6), and H (13.7 ± 2.6 kcal/min), but L did not differ from CON when data was analyzed for each sex. Male runners exhibited stepped increases in MC across loads and a weak-moderate relationship (r = 0.37; p < 0.01) between percentage change in absolute MC and increased percent body mass. A prediction model for MC (Δ% kcal/min = 0.98(Δ% body mass) - 0.91; SEE = ± 2.5%) was developed. For female runners, L increased MC by ~3.5% above CON, but no differentiation was found among L, M, and H, limiting the development of a prediction equation for females. Modest increases in body mass can produce detectable and potentially important levels of running economy impairment, but the relationship between changes in body mass and RE are complex, particularly in regards to sex.

Hydration Efficiency of a Protein Beverage Consumed in a Bolus vs. Metered Pattern during Recovery.

This study compared hydration efficiency of a carbohydrate-protein (CHO-PRO) beverage consumed in a bolus (BOL) vs. a metered (MET) drinking pattern during recovery from exercise induced hypohydration. Participants (n = 10) lost 2 - 2.5% of body mass from sweating during a morning exercise session. Participants were then assigned to either consume a carbohydrate/electrolyte/protein beverage in a bolus (BOL) or metered incremental consumption (MET) (counterbalanced) pattern post exercise. Total rehydration beverage administered during recovery equaled 125% of fluid lost during exercise. BOL was administered within the first hour of recovery, MET was administered 25% during the first 30 min, then 12.5% every 30 min for the next 4 hours. Mean (±SD) intake was 2475 ± 324 mL (MET) and 2525 ± 293 mL (BOL) (p = 0.22). Mean urine production was significantly greater for BOL (1167 ml ± 293 ml) than MET (730 ml ± 324 ml) (p = 0.003). Hydration efficiency (fluid ingested vs. fluid retained as percent) was significantly greater for MET (69.1 ± 15.4) than BOL (53.7 ± 9.7) (p = 0.004). Results indicate that, across a ~ 6-hour recovery, a metered drinking pattern improves fluid retention and therefore, hydration efficiency when a carbohydrate-protein beverage is consumed. More research is needed in paradigms characterized by unlimited fluid availability.

The effect of extrinsic factors on simulated 20-km time trial performance.

During time trials cyclists start individually with a uniform time gap between riders. With the exception of the first and last cyclists all riders will chase riders ahead and be chased from behind. The purpose of this study was to determine if cycling in a lead or chase position would influence 20-km time trial performance. Eight male cyclists performed four 20-km indoor time trials. During trial 1 (T1) individuals cycled as fast as possible. Prior to the start of trial 2 (T2) subjects were shown times and rank order from T1 and attempted to improve rank among opponents. After T2 subjects were ranked again and paired with the closest competitor. Subjects were alternately positioned to lead (TL) and chase (TC) in trials 3 and 4. TL and TC were counterbalanced. Means for time, mean power (MP), ratings of perceived exertion (RPE), and heart rate (HR) were recorded and pacing evenness was compared between trials using deviation scores (power variation at designated distances from overall mean). Repeated-measures analysis of variance (ANOVA) (alpha = 0.05) indicated no significant differences for HR or RPE. For time, T2 (33.84 ± 1.38 minutes) was significantly faster than T1 (34.80 ± 2.25 minutes) and MP was significantly greater (T1 = 229 ± 36 W, T2 = 243 ± 24 W). Time for TC (33.52 ± 1.33 minutes) was significantly faster than T1 (34.80 ± 2.25 minutes). Pacing during TC (9 ± 3 W) was significantly more even in comparison to TL (12 ± 1 W). No significant difference in performance was detected between TC and TL. In conclusion, extrinsic factors (chase vs. lead position) did not affect overall performance, even when pacing altered between trials; however, differences in performance times may represent meaningful differences in competitive settings.

Acute effects of chocolate milk and a commercial recovery beverage on postexercise recovery indices and endurance cycling performance.

To maximize training quality, athletes have sought nutritional supplements that optimize recovery. This study compared chocolate milk (CHOC) with a carbohydrate replacement beverage (CRB) as a recovery aid after intense exercise, regarding performance and muscle damage markers in trained cyclists. Ten regional-level cyclists and triathletes (maximal oxygen uptake 55.2 +/- 7.2 mL.kg(-1).min(-1)) completed a high-intensity intermittent exercise protocol, then 15-18 h later performed a performance trial at 85% of maximal oxygen uptake to exhaustion. Participants consumed 1.0 g carbohydrate.kg-1.h-1 of a randomly assigned isocaloric beverage (CHOC or CRB) after the first high-intensity intermittent exercise session. The same protocol was repeated 1 week later with the other beverage. A 1-way repeated measures analysis of variance revealed no significant difference (p = 0.91) between trials for time to exhaustion at 85% of maximal oxygen uptake (CHOC 13 +/- 10.2 min, CRB 13.5 +/- 8.9 min). The change in creatine kinase (CK) was significantly (p < 0.05) greater in the CRB trial than in the CHOC trial (increase CHOC 27.9 +/- 134.8 U.L(-1), CRB 211.9 +/- 192.5 U.L(-1)), with differences not significant for CK levels before the second exercise session (CHOC 394.8 +/- 166.1 U.L(-1), CRB 489.1 +/- 264.4 U.L(-1)) between the 2 trials. These findings indicate no difference between CHOC and this commercial beverage as potential recovery aids for cyclists between intense workouts.