Cells of the gliding bacterium Flavobacterium johnsoniae move rapidly over surfaces. Transposon mutagenesis was used to identify sprE, which is involved in gliding. Mutations in sprE resulted in the formation of nonspreading colonies on agar. sprE mutant cells in wet mounts were almost completely deficient in attachment to and movement on glass, but a small percentage of cells exhibited slight movements, indicating that the motility machinery was not completely disrupted. SprE is a predicted lipoprotein with a tetratricopeptide repeat domain. SprE is similar in sequence to Porphyromonas gingivalis PorW, which is required for secretion of gingipain protease virulence factors. Disruption of F. johnsoniae sprE resulted in decreased extracellular chitinase activity and decreased secretion of the cell surface motility protein SprB. Reduced secretion of cell surface components of the gliding machinery, such as SprB, may account for the defects in gliding. Orthologs of sprE are found in many gliding and nongliding members of the phylum Bacteroidetes, suggesting that similar protein secretion systems are common among members of this large and diverse group of bacteria.

Serum lactate is an important measurement taken in critical care settings for screening of lactic acidosis and as an indicator of sepsis. In addition, serial lactate testing provides essential information for evaluating therapy effectiveness and informing treatment decisions of critically ill patients at the point-of-care (POC). In this work, the performance of the Ohmx POC eDx Lactate test was evaluated and compared to the Nova Biomedical Lactate Plus Meter. This assay is introduced as the first test for a comprehensive bioelectronic POC instrument currently in development by Ohmx that will also offer procalcitonin and C-reactive protein tests for sepsis monitoring. Clinical sample testing shows an average recovery of 99% for measured sample lactate concentration relative to the Lactate Plus Meter for 60 samples. Correlation by Passing-Bablok regression yielded Lactate Plus = 1.03 Â Ohmx eDx + 0.22, r = 0.984 (n = 60; range of lactate values, 0.7-6.0 mmol/L). The lower limit of detection was 0.1 mmol/L. The lower and upper limits of quantification were 0.208 and 20 mmol/L, respectively. Intraday and total imprecision (% coefficient of variation) ranges from 5.7% to 9.1% across the assay range (0.2-20 mmol/L). These collective data clinically validate the Ohmx eDx Lactate assay and demonstrate the system's robust performance comparable to the Food and Drug Administration-cleared Lactate Plus Meter by Nova Biomedical.