Superior Specimen and Diagnostic Accuracy with Endoscopic Ultrasound-Guided Liver Biopsies Using 19-Gauge versus 22-Gauge Core Needles.

BACKGROUND/AIMS: Endoscopic ultrasound-guided liver biopsy (EUS-LB) is an effective and safe method of procuring liver tissue. The aims of this study were to assess and compare the outcomes and tissue adequacy of a single-pass, single-actuation, wet suction technique between 19 G and 22 G needles in patients undergoing EUS-LB. METHODS: We performed a prospective case series study of 20 patients undergoing EUS-LB at a single center between September 2017 and April 2020. The primary objective was to evaluate differences in sample adequacy via a single actuation wet suction technique between a 19 G core needle and a 22 G core needle. Adequacy was gauged by cumulative core biopsy length and the number of portal tracts visualized. RESULTS: The 19 G needle provided a longer core length (2.5 cm vs. 1.2 cm, p<0.0001), more complete portal tracts (5.8 vs. 1.7, p<0.0001), more total tracts (8.8 vs. 3, p<0.0001), and a longer, intact, fragment length (0.75 cm vs. 0.32 cm, p<0.0006). The 19 G needle was superior in providing adequate (60% vs. 5%, p<0.001) and diagnostic pathologic samples (85% vs. 10%, p<0.001). CONCLUSION: A single-pass, single-actuation, wet suction technique using a 19 G needle is superior to that using a 22 G needle for tissue acquisition and sample adequacy in EUS-LB.

Structural, Biochemical, and In Vivo Characterization of MtrR-Mediated Resistance to Innate Antimicrobials by the Human Pathogen Neisseria gonorrhoeae.

Neisseria gonorrhoeae responds to host-derived antimicrobials by inducing the expression of the mtrCDE-encoded multidrug efflux pump, which expels microbicides, such as bile salts, fatty acids, and multiple extrinsically administered drugs, from the cell. In the absence of these cytotoxins, the TetR family member MtrR represses the mtrCDE genes. Although antimicrobial-dependent derepression of mtrCDE is clear, the physiological inducers of MtrR are unknown. Here, we report the crystal structure of an induced form of MtrR. In the binding pocket of MtrR, we observed electron density that we hypothesized was N-cyclohexyl-3-aminopropanesulfonic acid (CAPS), a component of the crystallization reagent. Using the MtrR-CAPS structure as an inducer-bound template, we hypothesized that bile salts, which bear significant chemical resemblance to CAPS, are physiologically relevant inducers. Indeed, characterization of MtrR-chenodeoxycholate and MtrR-taurodeoxycholate interactions, both in vitro and in vivo, revealed that these bile salts, but not glyocholate or taurocholate, bind MtrR tightly and can act as bona fide inducers. Furthermore, two residues, W136 and R176, were shown to be important in binding chenodeoxycholate but not taurodeoxycholate, suggesting different binding modes of the bile salts. These data provide insight into a crucial mechanism utilized by the pathogen to overcome innate human defenses.IMPORTANCENeisseria gonorrhoeae causes a significant disease burden worldwide, and a meteoric rise in its multidrug resistance has reduced the efficacy of antibiotics previously or currently approved for therapy of gonorrheal infections. The multidrug efflux pump MtrCDE transports multiple drugs and host-derived antimicrobials from the bacterial cell and confers survival advantage on the pathogen within the host. Transcription of the pump is repressed by MtrR but relieved by the cytosolic influx of antimicrobials. Here, we describe the structure of induced MtrR and use this structure to identify bile salts as physiological inducers of MtrR. These findings provide a mechanistic basis for antimicrobial sensing and gonococcal protection by MtrR through the derepression of mtrCDE expression after exposure to intrinsic and clinically applied antimicrobials.

Acute Pancreatitis Task Force on Quality: Development of Quality Indicators for Acute Pancreatitis Management.

INTRODUCTION: Detailed recommendations and guidelines for acute pancreatitis (AP) management currently exist. However, quality indicators (QIs) are required to measure performance in health care. The goal of the Acute Pancreatitis Task Force on Quality was to formally develop QIs for the management of patients with known or suspected AP using a modified version of the RAND/UCLA Appropriateness Methodology. METHODS: A multidisciplinary expert panel composed of physicians (gastroenterologists, hospitalists, and surgeons) who are acknowledged leaders in their specialties and who represent geographic and practice setting diversity was convened. A literature review was conducted, and a list of proposed QIs was developed. In 3 rounds, panelists reviewed literature, modified QIs, and rated them on the basis of scientific evidence, bias, interpretability, validity, necessity, and proposed performance targets. RESULTS: Supporting literature and a list of 71 proposed QIs across 10 AP domains (Diagnosis, Etiology, Initial Assessment and Risk Stratification, etc.) were sent to the expert panel to review and independently rate in round 1 (95% of panelists participated). Based on a round 2 face-to-face discussion of QIs (75% participation), 41 QIs were classified as valid. During round 3 (90% participation), panelists rated the 41 valid QIs for necessity and proposed performance thresholds. The final classification determined that 40 QIs were both valid and necessary. DISCUSSION: Hospitals and providers managing patients with known or suspected AP should ensure that patients receive high-quality care and desired outcomes according to current evidence-based best practices. This physician-led initiative formally developed 40 QIs and performance threshold targets for AP management. Validated QIs provide a dependable quantitative framework for health systems to monitor the quality of care provided to patients with known or suspected AP.

Crystal structure of peroxide stress regulator from Streptococcus pyogenes provides functional insights into the mechanism of oxidative stress sensing.

Regulation of oxidative stress responses by the peroxide stress regulator (PerR) is critical for the in vivo fitness and virulence of group A Streptococcus. To elucidate the molecular mechanism of DNA binding, peroxide sensing, and gene regulation by PerR, we performed biochemical and structural characterization of PerR. Sequence-specific DNA binding by PerR does not require regulatory metal occupancy. However, metal binding promotes higher affinity PerR-DNA interactions. PerR metallated with iron directly senses peroxide stress and dissociates from operator sequences. The crystal structure revealed that PerR exists as a homodimer with two metal-binding sites per subunit as follows: a structural zinc site and a regulatory metal site that is occupied in the crystals by nickel. The regulatory metal-binding site in PerR involves a previously unobserved HXH motif located in its unique N-terminal extension. Mutational analysis of the regulatory site showed that the PerR metal ligands are involved in regulatory metal binding, and integrity of this site is critical for group A Streptococcus virulence. Interestingly, the metal-binding HXH motif is not present in the structurally characterized members of ferric uptake regulator (Fur) family but is fully conserved among PerR from the genus Streptococcus. Thus, it is likely that the PerR orthologs from streptococci share a common mechanism of metal binding, peroxide sensing, and gene regulation that is different from that of well characterized PerR from Bacillus subtilis. Together, our findings provide key insights into the peroxide sensing and regulation of the oxidative stress-adaptive responses by the streptococcal subfamily of PerR.