Evaluation of a Gastrointestinal Pathogen Panel Immunoassay in Stool Testing of Patients with Suspected Clostridioides (Clostridium) difficile Infection.

Clostridioides (Clostridium) difficile infection (CDI) is the most common causative pathogen of health care-associated gastrointestinal infections; however, due to the overlap of clinical symptoms with those of other causes of acute gastroenteritis, the selection of the most appropriate laboratory test is difficult. From April to October 2018, 640 stool samples requested for CDI testing were examined using the mariPOC CDI and Gastro test (ArcDia), which allows the detection of C. difficile glutamate dehydrogenase (GDH) and toxin A/B, norovirus genogroups GI and GII.4, rotavirus, adenovirus, and Campylobacter spp. In parallel, the C. Diff Quik Chek Complete test (Alere) was used as a routine diagnostic assay, and C. difficile toxigenic culture was used as a reference method. The sensitivity of the mariPOC CDI and Gastro test was comparable to that of C. Diff Quik Chek Complete for the detection of GDH (96.40% [95% confidence interval {CI}, 91.81% to 98.82%] versus 95.68% [95% CI, 90.84 to 98.40%]; P = 1.00) and was higher for the detection of toxin A/B (66.67% [95% CI, 57.36 to 75.11%] versus 55.56% [95% CI, 46.08 to 64.74%]; P = 0.00). The specificity of the mariPOC CDI and Gastro test was lower than that of C. Diff Quik Chek Complete for GDH detection (95.21% [95% CI, 92.96% to 96.91%] versus 97.60% [95% CI, 95.85% to 98.76%]; P = 0.04) and comparable to that of C. Diff Quik Chek Complete for toxin A/B detection (99.24 [95% CI, 98.05% to 99.79%] versus 99.81% [95% CI, 98.94% to 100.0%]; P = 0.37). In 29 cases (4.53%), other causative agents of diarrhea were detected (Campylobacter spp. [n = 17], rotavirus [n = 7], and norovirus genogroup GII.4 [n = 5]).

[Comparing traditional and commercial molecular biology detection of gastrointestinal pathogens with AusDiagnostics panels in Motol University Hospital].

BACKGROUND: The aim was to do an internal audit of gastrointestinal pathogen detection at the Department of Medical Microbiology, Motol University Hospital between the years 2014 and 2018 and to test two commercial multiplex molecular biology assays potentially improving the diagnostic process and reducing costs. MATERIAL AND METHODS: Based on data from a laboratory information system (LIS), a total of 45,888 samples were identified which had been tested for the presence of gastrointestinal pathogens using culture, immunochromatographic, microscopic and molecular biology techniques between 2014-2018. Novel multiplex molecular biology detection was used to test 182 nucleic acid isolates obtained from stool samples with the Enteric Viruses (8-well) assay (Viral Panel, EVP) or Faecal Pathogens M (16-well) assay (Microbial Panel, FPM) manufactured by AusDiagnostics. RESULTS: The LIS data showed 6.2 % of positive pathogens causing diarrhea from all tested samples (detection rates: 4.5 % for bacterial agents, 21.6 % for viral agents and 0.4 % for parasitic agents). Valid samples (98.9 % of all tested samples) tested by the molecular biology technique yielded, in descending order: C. difficile toxin B (19 %), norovirus (9 %), astrovirus (8 %), Campylobacter (7 %), sapovirus (6 %), Yersinia enterocolitica (6 %), rotavirus (4 %), enterovirus (3 %), Aeromonas (3 %), adenovirus (2 %) and Salmonella (1 %). There was found at least 1 additional new positive detection in 27 % of stools tested by the Viral Panel and in 40 % of stools tested by the Microbial Panel in comparison with the traditional approach. Introducing the panels into routine diagnostic practice will not reduce the costs. CONCLUSIONS: The introduction of novel multiplex molecular biology assays for detecting gastrointestinal pathogens will considerably increase pathogen detection rates even though the costs will be higher for the Department of Medical Microbiology.

Plasma EBV-DNA monitoring in Epstein-Barr virus-positive Hodgkin lymphoma patients.

Epstein-Barr virus (EBV) is associated with approximately one-third of Hodgkin lymphoma (HL) cases. EBV-DNA is often present in the plasma and whole blood of EBV-associated HL patients. However, the significance of EBV-DNA monitoring is debated. In a cohort of 165 adult HL patients, EBV-DNA viral load was prospectively monitored both in the plasma and whole blood. Diagnostic tissue samples of all patients were histologically reviewed; in 72% nodular sclerosis was detected, 24% presented with mixed cellularity (MC), and 5% had other type of HL. Tissues from 150 patients were also analyzed for the presence of latent EBV infection using in situ hybridization for EBV-encoded RNA (EBER) and immunohistochemistry for latent membrane protein (LMP1). Using these methods, 29 (19%) patients were classified as EBV positive. Using real-time quantitative PCR, 22 (76%) of EBV-positive HL patients had detectable EBV-DNA in the plasma and 19 (66%) patients in whole blood prior to therapy. In the group of EBV-negative HL cases, three (2%) patients had detectable plasma EBV-DNA and 30 (25%) patients whole blood EBV-DNA before treatment. EBV-positive HL was significantly associated with EBV-DNA positivity both in the plasma and whole blood in pretreatment samples, increasing age and MC subtype. Serial analysis of plasma EBV-DNA showed that response to therapy was associated with decline in viral load. Moreover, significantly increased plasma EBV-DNA level recurred before disease relapse in one patient. Our results further suggest that the assessment of plasma EBV-DNA viral load might be of value for estimation of prognosis and follow-up of patients with EBV-positive HL.

HHV-6 DNA throughout the tissues of two stem cell transplant patients with chromosomally integrated HHV-6 and fatal CMV pneumonitis.

Two patients with the characteristic high human herpesvirus 6 (HHV-6) DNA loads in peripheral blood caused by chromosomally integrated (CI) virus received a haematopoietic stem cell transplant (HSCT) from a donor without CI HHV-6. Both patients died in consequence of cytomegalovirus (CMV) pneumonitis. At autopsy, high amounts of CMV DNA were detected in lungs but at much lower levels in other organs. In contrast HHV-6 DNA was detected at high levels throughout the organs with the exception of donor-derived haematopoietic tissue. In individuals with chromosomal integration, HHV-6 DNA is found in every tissue of recipient origin indicating inheritance through the germ line.

Cytomegalovirus encephalitis/retinitis in allogeneic haematopoietic stem cell transplant recipient treated successfully with combination of cidofovir and foscarnet.

We report an 18-yr-old female patient with repeated CMV reactivations after HSCT treated by several pre-emptive courses of virostatic therapy. Seven months after HSCT, she developed CMV encephalitis/retinitis. Initial therapy with GCV and hyperimmune globulin failed, and later on GCV-resistant strain was detected. Continual increase of CMV DNA in peripheral blood led us to combined therapy with CDV and FCV, which was successful and free of severe renal toxicity. To our best knowledge, this is the first reported case of successful CMV treatment with a combination of CDV and FCV.