Search

The human biliary system, a mucosal barrier tissue connecting the liver and intestine, is an organ often affected by serious inflammatory and malignant diseases. Although these diseases are linked to immunological processes, the biliary system represents an unexplored immunological niche. By combining endoscopy-guided sampling of the biliary tree with a high-dimensional analysis approach, comprehensive mapping of the human biliary immunological landscape in patients with primary sclerosing cholangitis (PSC), a severe biliary inflammatory disease, was conducted. Major differences in immune cell composition in bile ducts compared to blood were revealed. Furthermore, biliary inflammation in patients with PSC was characterized by high presence of neutrophils and T cells as compared to control individuals without PSC. The biliary T cells displayed a CD103+CD69+ effector memory phenotype, a combined gut and liver homing profile, and produced interleukin-17 (IL-17) and IL-22. Biliary neutrophil infiltration in PSC associated with CXCL8, possibly produced by resident T cells, and CXCL16 was linked to the enrichment of T cells. This study uncovers the immunological niche of human bile ducts, defines a local immune network between neutrophils and biliary-resident T cells in PSC, and provides a resource for future studies of the immune responses in biliary disorders.

Urinary antigen tests (UATs) are often used to diagnose Legionnaires' disease as they are rapid and easy to perform on readily obtainable urine samples without the need for specialized skills compared to conventional methods. Recently developed automated readers for UATs may provide objective results interpretation, especially in cases of weak result bands. Using 53 defined patient urine samples, we evaluated the performance of the BinaxNOW Legionella Antigen Card (Abbott), ImmuView S. pneumoniae and Legionella (SSI Diagnostica), STANDARD F Legionella Ag FIA (SD Biosensor), and Sofia Legionella FIA (Quidel) simultaneously with their respective automated readers. Automatic and visual interpretation of result bands were also compared for the immunochromatography-based BinaxNOW and ImmuView UATs. Overall sensitivity and specificity of Legionella UATs were 53.9-61.5% and 90.0-94.9%, respectively. All four UATs successfully detected all samples from L. pneumophila serogroup 1-positive patients, but most failed to detect samples for Legionella spp., or other serogroups. Automatic results interpretation of results was found to be mostly concordant with visual results reading. In conclusion, the performance of the four UATs were similar to each other in the detection of Legionella urinary antigen with no major difference between automated or visual results reading.

Blood culture (BC) often fails to detect bloodstream microorganisms in sepsis. However, molecular diagnostics hold great potential. The molecular method PCR/electrospray ionization-mass spectrometry (PCR/ESI-MS) can detect DNA from hundreds of different microorganisms in whole blood. The aim of the present study was to evaluate the performance of this method in a multicenter study including 16 teaching hospitals in the USA (n=13) and Europe (n=3). First, on 2,754 contrived whole blood samples, with or without spiked microorganisms, PCR/ESI-MS produced 99.1% true positive and 97.2% true negative results. Secondly, among 1,460 patients with suspected sepsis (sepsis-2 definition), BC and PCR/ESI-MS on whole blood were positive in 14.6% and 25.6% of cases, respectively, with the following result combinations: BC+/PCR/ESI-MS-, 4.3%; BC+/PCR/ESI-MS+, 10.3%; BC-/PCR/ESI-MS+, 15.3%; and BC-/PCR/ESI-MS-, 70.1%. Compared with BC, PCR/ESI-MS showed the following sensitivities (coagulase-negative staphylococci not included): Gram-positive bacteria, 58%; Gram-negative bacteria, 78%; and Candida species, 83%. The specificities were > 94% for all individual species. Patients treated with prior antimicrobial medications (n=603) had significantly increased PCR/ESI-MS positivity rates compared with patients without prior antimicrobial treatment, 31% vs 22% (p<0.0001), with pronounced differences for Gram-negative bacteria and Candida species. In conclusion, PCR/ESI-MS showed excellent performance on contrived samples. On clinical samples, it showed high specificities, moderately high sensitivities for Gram-negative bacteria and Candida species, and elevated positivity rates during antimicrobial treatment. These promising results encourage further development of molecular diagnostics on whole blood for detection of bloodstream microorganisms in sepsis., Funding Agencies:Ibis Biosciences, a division of Abbott Abbott LaboratoriesCepheid ContraFect Nabriva Therapeutics AG Lajolla Pharmaceuticals Alere Corporation Spectral Diagnostics Ferring Pharmaceuticals Inflammix VICTASm Sanofi Pasteur Inc. Curetis GmbH PfizerMerck & CompanyCidara Therapeutics Inc. Shire Aridis Pharmaceuticals Inc. Epigenomics Inc. Roche Holding GenentechFinch Therapeutics Seres Therapeutics Inc. Diasorin Molecular Janssen Research and Development NeuMoDx Molecular Iterum Therapeutics International

Blood volume is the most important variable, for detection of microorganisms in blood cultures (BC). Most standards recommend 40-60 ml blood, collected in several BC bottles filled up to 10 ml. We measured blood volume in individual BC bottles, and analysed the association of hospital, bottle type, day of the week, daily sampling time, and age and gender of the patient, with sampling volume and BC result. The variation in blood volume per BC bottle was analysed in a mixed linear model using hospital, bottle type, weekday, sampling time, age and gender as fixed factors, and patient ID and episode as random factors to control for repetitive sampling of individual patients. Only 18 % of all bottles were filled with the recommended 8-10 ml, and 47 % were filled with less than 8 ml. The mean (±SE) volume was larger in positive 9.09 (±0.15) compared to negative bottles 8.47 (±0.07) (p<0.001). Blood volume was larger in BacT/ALERT-FA Plus than in -FN Plus BC bottles (p<0.001). There was significantly lower volumes collected during the night (p<0.001). The volume of blood collected decreased significantly with increasing patient age (p<0.001). Larger volumes were collected from males compared to females, 8.78 (±0.06) vs. 8.36 (±0.06) ml (mean ± SE) respectively (p<0.001). The odds of detecting a positive patient increases with 13 % for each additional ml blood drawn. Our results show that we need to work actively with development of blood sampling routines to overcome age and gender effects, and to optimize blood sampling volumes.

The usefulness of pneumococcal urinary antigen tests (UATs) in severe pneumococcal infection relies heavily on the performance in bacteremic patients. Fluorescence technology and automatic reading of test results may improve UAT performance. We evaluated the automatically read Sofia S. pneumoniae FIA for diagnosing pneumococcal bloodstream infection (BSI) in hospitalized adult patients. First, the Sofia FIA was evaluated on 97 patients with pneumococcal (n = 47) and nonpneumococcal (n = 50) BSI and compared with results by the visually read BinaxNOW S. pneumoniae immunochromatographic test (ICT) and ImmuView S. pneumoniae and Legionella pneumophila ICT. In four cases (4.1%), the Sofia FIA showed invalid test results, three of which showed invalid results by the ImmuView ICT previously. Based on 93 valid cases, the Sofia FIA showed similar sensitivity (for both comparisons: 68% versus 62%; P = 0.45) and specificity (for both comparisons: 91% versus 93%; P = 1.00) as the visually read UATs. Second, the Sofia FIA was prospectively evaluated on 82 consecutive nonfrozen urine samples, detecting pneumococcal antigen in 10 of 14 (sensitivity, 71%) pneumococcal BSI patients, similarly to the visually and automatically read BinaxNOW ICT (both 12 of 14; sensitivity, 86%; P = 0.50). Of five nonpneumococcal BSI cases, the Sofia FIA showed an invalid test result in one case, but no positive UAT results were obtained. Thus, the sensitivity and specificity of the Sofia FIA were similar to the performance rates of other UATs in patients with BSI, but invalid test results are of concern for the usefulness in pneumococcal BSI., Funding Agency:Region Örebro County Council Research Committee OLL-723721

Meeting Abstract: PP4.109