The salivary microbiota of patients with acute lower respiratory tract infection-A multicenter cohort study.

The human microbiome contributes to health and disease, but the oral microbiota is understudied relative to the gut microbiota. The salivary microbiota is easily accessible, underexplored, and may provide insight into response to infections. We sought to determine the composition, association with clinical features, and heterogeneity of the salivary microbiota in patients with acute lower respiratory tract infection (LRTI). We conducted a multicenter prospective cohort study of 147 adults with acute LRTI presenting to the emergency department of seven hospitals in three states (Pennsylvania, Michigan, and Ohio) between May 2017 and November 2018. Salivary samples were collected in the emergency department, at days 2-5 if hospitalized, and at day 30, as well as fecal samples if patients were willing. We compared salivary microbiota profiles from patients to those of healthy adult volunteers by sequencing and analyzing bacterial 16-rRNA. Compared to healthy volunteers, the salivary microbiota of patients with LRTI was highly distinct and strongly enriched with intestinal anaerobes such as Bacteroidaceae, Ruminococcaceae, and Lachnospiraceae (e.g., mean 10% relative abundance of Bacteroides vs < 1% in healthy volunteers). Within the LRTI population, COPD exacerbation was associated with altered salivary microbiota composition compared to other LRTI conditions. The largest determinant of microbiota variation within the LRTI population was geography (city in which the hospital was located).

Effects of Transport Temperature on the Stability of Inflammatory, Hemostasis, Endothelial Function, and Oxidative Stress Plasma Biomarker Concentrations.

BACKGROUND: A number of studies in critically ill patients are conducted outside the hospital. Specimens should ideally be transported from out-of-hospital setting to a laboratory using dry ice, but this approach is expensive and may not be feasible in some circumstances. We, therefore, examined the impact of temperature during transport of specimens on the precision of biomarker concentrations. OBJECTIVE: To determine the effects of transport temperature conditions on biomarker concentrations in specimens processed within 1 h of collection. METHODS/PATIENTS: We simulated transport by storing specimens at four temperature conditions: packaged at -80°C (control), on dry ice (-79°C), on cold gel packs (4°C), and at room temperature (RT, 21°C). We examined eight biomarkers spanning four signaling domains- inflammation, hemostasis, endothelial dysfunction, and oxidative stress. We calculated mean, median, and percent difference for each biomarker concentration compared with the control transport temperature at -80°C in 26 subjects (16 hospitalized with severe sepsis and 10 non-hospitalized volunteers). RESULTS: Patients with severe sepsis had log-fold higher median concentrations of IL-6, hs-CRP, D-dimer, E-selectin, sICAM-1, and sVCAM-1 compared with non-hospitalized volunteers (P <0.05). When specimens were combined, we observed a ≤7% difference in the mean and median IL-6, hs-CRP, D-dimer, PAI-1, E-selectin, s-ICAM, s-VCAM, and nitrite concentrations for dry ice and cold gel packs transport compared with transport at -80°C (P>0.05). Larger differences (up to 12%) were observed when biomarker concentrations for PAI-1 and s-VCAM at room temperature were compared with transport at -80°C (P >0.05). CONCLUSIONS: Select inflammatory, coagulation, endothelial dysfunction, and oxidative stress biomarkers can be transported at 4°C on gel packs for 24 h with minimal effects on precision.

Clinical laboratory verification of thyroglobulin concentrations in the presence of autoantibodies to thyroglobulin: comparison of EIA, radioimmunoassay and LC MS/MS measurements in an Urban Hospital.

OBJECTIVE: Thyroglobulin (Tg) measurements assess recurrence in post-thyroidectomy thyroid cancer patients. Tg measurements by enzyme immunoassays (EIA) can be falsely elevated by interference from Tg autoantibodies (TgAb). Radioimmunoassay (RIA) is less susceptible to TgAb interference and has been the standard-of-care test for TgAb positive patients. Recently developed liquid chromatography tandem mass spectrometry (LC-MS/MS) methods may eliminate TgAb interference. We assessed the performance of Tg measurements by EIA, RIA and LC-MS/MS to evaluate TgAb interference differences. RESULTS: We measured TgAb and Tg in 50 plasma samples from 40 patients in whom Tg measurement was part of their routine follow-up and 10 healthy volunteers. Discrepancy between EIA and both LC-MS/MS and RIA was observed at low Tg concentrations (≤ 7.55 ng/mL) in TgAb positive specimens (LC-MS/MS = 1.9 * EIA - 0.03, r = 0.68). RIA and LC-MS/MS Tg measurements in TgAb positive specimens with low Tg concentrations had improved correlation but demonstrated bias (LC MS/MS = 0.6 * RIA - 1.4, r = 0.90). Disagreement between methods may be attributed to LC-MS/MS reported Tg concentrations as undetectable compared to RIA. It seems likely that most discrepant cases are falsely elevated in RIA due to TgAb interference, however, some cases appear below the detection limit of LC-MS/MS; implementation of LC-MS/MS by clinicians will require lower detection limits.