Interpreting desirability of outcome ranking (DOOR) analyses in observational studies in infectious diseases: caution still needed

Serological diagnostics of Lyme borreliosis: comparison of assays in twelve clinical laboratories in Northern Europe Abstract Lyme borreliosis (LB), caused by spirochetes belonging to the Borrelia burgdorferi sensu lato complex, is the most common tick-borne infection in Europe. Laboratory diagnosis of LB is mainly based on the patients’ medical history, clinical signs and symptoms in combination with detection of Borrelia-specific antibodies where indirect enzyme-linked-immunosorbent assay (ELISA) is the most widely used technique. The objective of the study was to evaluate and compare the diagnostic accuracy (sensitivities and specificities) of serological tests that are currently in use for diagnosis of LB in clinical laboratories in Northern Europe, by use of a large serum panel. The panel consisted of 195 serum samples from well-characterized and classified patients under investigation for clinically suspected LB (n = 59) including patients with Lyme neuroborreliosis, Lyme arthritis, acrodermatitis chronica atrophicans, erythema migrans or other diseases (n = 112). A total of 201 serum samples from healthy blood donors were also included. The panel (396 serum samples altogether) was sent to 12 clinical laboratories (using five different ELISA methods) as blinded for group affiliation and the laboratories were asked to perform serological analysis according to their routine procedure. The results from the study demonstrated high diagnostic concordance between the laboratories using the same diagnostic assay and lower diagnostic concordance between laboratories using different diagnostic assays. For IgG, the results were in general rather homogenous and showed an average sensitivity of 88% (range 85–91%) compared to IgM which showed lower average sensitivity of 59% (range 50–67%) and more heterogeneous results between assays and laboratories.

Evaluation of anidulafungin in the treatment of intra-abdominal candidiasis: a pooled analysis of patient-level data from 5 prospective studies Abstract The incidence of nosocomial invasive fungal infections involving Candida spp. has increased markedly in recent years in patients undergoing abdominal surgery. This post hoc analysis aimed to determine the efficacy and safety of anidulafungin treatment in patients with intra-abdominal candidiasis (IAC) from five prospective studies (one comparative and four open-label) of adult surgical patients with microbiologically confirmed Candida intra-abdominal infection. Patients received an intravenous (IV) loading dose of anidulafungin 200 mg, followed by a daily 100-mg maintenance dose. Per study protocols, some patients could be switched to an oral azole after ≥ 5 or ≥ 10 days of IV treatment. Antifungal treatment was maintained for ≥ 14 days after the last positive Candida culture and resolution of symptoms. The global response rate (GRR) at the end of IV treatment (EOIVT) was the primary endpoint. GRR at the end of therapy (EOT), all-cause mortality at days 14 and 28, and safety was also evaluated. Seventy-nine patients had IAC from peritoneal fluid or hepatobiliary tract. C. albicans (72.2%) and C. glabrata (32.9%) were the most common pathogens. Overall GRR was 73.4% and 67.1% at EOIVT and EOT, respectively. All-cause mortality was 17.7% at day 14 and 24.1% at day 28 in the modified intent-to-treat population. Anidulafungin was well tolerated in this population, with most adverse events mild or moderate in severity. In these patients with IAC, anidulafungin showed a GRR at EOIVT similar to the anidulafungin registrational trial, and the results of our analysis confirmed the known safety profile of anidulafungin. ClinicalTrials.gov registration number NCT00496197, registered July 3, 2007, https://clinicaltrials.gov/ct2/show/study/NCT00496197; ClinicalTrials.gov registration number NCT00548262, registered October 19, 2007, https://clinicaltrials.gov/ct2/show/record/NCT00548262; ClinicalTrials.gov registration number NCT00537329, registered September 25, 2007, https://clinicaltrials.gov/ct2/show/record/NCT00537329; ClinicalTrials.gov registration number NCT00689338, registered May 29, 2008, https://clinicaltrials.gov/ct2/show/study/NCT00689338; ClinicalTrials.gov registration number NCT00805740, registered November 26, 2008, https://clinicaltrials.gov/ct2/show/NCT00805740

Seroepidemiology of syphilis among men who have sex with men in Burkina Faso, West Africa Abstract Men who have sex with men (MSM) have a disproportionate risk of acquiring sexually transmitted infections (STIs), such as syphilis. However, prevalence and determinants of syphilis among this population are less known in West Africa. This study aims to estimate syphilis prevalence among MSM in Burkina Faso. We conducted a cross-sectional biological and behavior survey in the two main cities of Burkina Faso, Ouagadougou and Bobo-Dioulasso. MSM were recruited using Respondent Driven Sampling (RDS) methods. Data were collected from January to April 2013 in Ouagadougou and from May to August 2013 in Bobo-Dioulasso. Out of the 657 MSM screened for syphilis, 6.1% (40/657) tested positive for Treponema pallidum antibodies and 1.1% (7/657) for active syphilis. Population-weighted prevalence of active syphilis was 2.1% (95% CI, 01.1–04.4) in Ouagadougou and 0.0% in Bobo-Dioulasso. Serologic markers of syphilis (anti-Treponema antibodies) were found among 7.4% (95% CI 5.0–10.8) of MSM in Ouagadougou and 5.0% (95% CI 3.1–8.0) in Bobo-Dioulasso. No significant differences were found in syphilis serological markers prevalence by participants’ sociodemographic and behavioral characteristics. The prevalence of syphilis among MSM is low and comparable to that of other individuals of reproductive age in Burkina Faso. This low prevalence is very encouraging and suggests implementation of effective public health intervention programs which direct resources and services toward MSM to prevent further spread of syphilis infection and to limit HIV transmission in this group.

Establishing a donor stool bank for faecal microbiota transplantation: methods and feasibility Abstract Faecal microbiota transplantation (FMT) is a promising treatment, but donor selection and implementation in clinical practice are difficult. Here, we describe the establishment of a donor stool bank based on the Tissue Act. Stool donors were recruited among blood donors and asked to donate five times in a month. A screening questionnaire, a medical interview and testing of blood and stool were conducted before and after donations. Donations were made at home and transported to the lab, where 50 g of stool was suspended and filtered in saline and 20-mL glycerol (final concentration of 10%) to a volume of 170 mL. The processed stool was assigned a batch number, frozen within 2 h after defecation and stored at − 80 °C for up to 1 year. All steps were documented and cross-checked before donor stool were released for clinical use. Thirteen donors were eligible at the first interview and started donations. Two donors were excluded due to a positive Helicobacter pylori test, two withdrew consent and one was lost to follow-up. One donor took a single dose of NSAIDs 2 days prior to a donation, which was discarded. There were no other excluding findings at the second interview or testing. Eight of the 13 donors were approved as stool donors. All donated five times with each donation yielding 1–6 portions. Eighty-four portions were released for clinical use. Recruiting stool donors among blood donors is safe and effective. The Tissue Act yields an appropriate regulative framework for FMT.

Analysis of Streptococcus pneumoniae using Fourier-transformed infrared spectroscopy allows prediction of capsular serotype Abstract Determination of the capsule type of clinical isolates of Streptococcus pneumoniae is a prerequisite for epidemiological studies and further vaccine development. The Quellung reaction for serotyping is expensive and mostly done in reference centres. We wanted to evaluate whether Fourier-transformed infrared (FT-IR) spectroscopy is suitable for capsular type analysis and prediction of pneumococcal serotypes. We used the IR-Biotyper™ (Bruker) to create a database containing the spectra of 120 strains from invasive disease. The strains covered the 24 vaccine serotypes contained in the 13-valent conjugate vaccine (PCV13) and the 23-valent polysaccharide vaccine (PSV23). Hierarchical clustering analysis was performed. Finally, two different classification sets were created (PCV13 and PSV23). They were used to predict the serotype of 168 different challenge strains (invasive and non-invasive disease) covering 48 different serotypes (vaccine and non-vaccine types). FT-IR spectra from pneumococci (1300–800 cm−1) clustered along their serotype as determined by the Quellung reaction (120 strains, 24 different serotypes). Strains with unknown serotype fell within the cluster of the correct serotype, as long as the latter was represented in the database (168 strains, 48 different serotypes). Concordance between the Quellung reaction and FT-IR spectroscopy was excellent (kappa ≥ 0.75). FT-IR spectroscopy is a fast and cost-effective method to predict the capsular serotype of pneumococci.

A 5-year study of human parechoviruses in children living in bad sanitation conditions and non-polio acute flaccid paralysis children from Greece Abstract In Greece, data for human parechoviruses (HPeVs) are scarce and our aim was to conduct a large scale study to determine for the first time their occurrence. Under the spectrum of surveillance, we retrospectively screened stool specimens obtained from 71 children with acute flaccid paralysis (AFP) symptoms and from 311 individuals in high-risk population groups such as children living in bad sanitation conditions for HPeVs presence by rRT-PCR targeting the 5′ UTR. All positive samples were then genotyped by targeting the HPeVs VP1 region. Totally, 15/311 (5%) stool samples from children living in bad sanitation conditions and 4/71 (6%) from the non polio AFP children were positive for HPeVs. Sequencing analysis revealed that genotypes HPeV1 (n = 4/15), HPeV5 (n = 2/15), and HPeV6 (n = 2/15) were circulating among Roma children population whereas HPeV1 (n = 1/4) and HPeV5 (n = 1/4) were circulating in children with AFP-like symptoms. We did not obtain a seasonality motive among HPeV1 or HPeV5 genotypes whereas HPeV6 was detected only in July. Phylogenetic analysis showed that Greek HPeVs strains are clustered together with HPeV strains circulating in other European countries during the same period. We describe the presence of HPeVs in Greece, and we enforce that their diagnosis should be considered in children with neurological outcome such as non-polio AFP.

Detection of carbapenemase producers by matrix-assisted laser desorption-ionization time-of-flight mass spectrometry (MALDI-TOF MS) Abstract Matrix-assisted laser desorption-ionization time-of-flight mass spectrometry (MALDI-TOF MS) has been recently applied in detection of carbapenemase-producing Gram-negative isolates. In the present study, we review the latest developments in this field.

Development and validation of external quality assessment panels for mycobacterial culture testing to diagnose tuberculosis in China Abstract Mycobacterial culture remains the gold standard for detection of Mycobacterium tuberculosis (MTB) in clinical samples. However, no external quality assessment (EQA) tools exist to validate results obtained using this sophisticated method. Therefore, we developed EQA panels to assess the quality of mycobacterial culture results produced by designated TB hospitals in China. Artificial sputum containing methylcellulose was used to supplement quantified mycobacterial solutions to simulate culture-negative and culture-positive clinical sputum samples of low or high mycobacterial concentration, respectively. After storage of the quantified simulated EQA panels for 4 weeks at 4 °C, experimental bacterial quantification of the panels was again conducted, with no impact of artificial sputum on mycobacterial culture results observed. Next, 47 tuberculosis (TB) hospitals were recruited for evaluation of the EQA panels. Overall, 29 hospitals (61.7%) produced mycobacterial culture test results matching expected results for the EQA panels, while the remaining 18 (38.3%) hospitals did not. False-negative results for the low mycobacterial concentration panel sample accounted for 33 (73.3%) diagnostic errors. Compared with hospitals using solid culture methods as a control group, hospitals using the liquid culture method were less likely to produce uncertified results (aOR 0.064, 95% CI 0.005–0.770). In conclusion, we first developed then evaluated EQA panels for validation of mycobacterial culture testing in China. Our data demonstrate that approximately one-third of TB hospitals failed to produce results that met criteria for classification as certified mycobacterial culture testing providers, emphasizing the importance of quality control and quality assurance in TB diagnostics.

Fusobacterium nucleatum tumor DNA levels are associated with survival in colorectal cancer patients Abstract There is increasing evidence indicating a role for Fusobacterium nucleatum (F. nucleatum) in colorectal cancer (CRC) development and prognosis. This study evaluated F. nucleatum as a prognostic biomarker, by assessing its association with post-diagnosis survival from CRC. From September 2008 to April 2012 CRC patients (n = 190) were recruited from three hospitals within the Czech Republic. F. nucleatum DNA copies were measured in adjacent non-malignant and colorectal tumor tissues using quantitative real-time PCR. Cox Proportional Hazards (HR) models were applied to evaluate the association between F. nucleatum DNA and overall survival, adjusting for key confounders. Risk prediction modeling was conducted to evaluate the ability to predict survival based on F. nucleatum status. High, compared with low, levels of F. nucleatum in colorectal tumor tissues were associated with poorer overall survival (adjusted HR 1.68, 95% CI 1.02–2.77), which was slightly attenuated after additional adjustment for microsatellite instability status. However, inclusion of F. nucleatum in risk prediction models did not improve the ability to identify patients who died beyond known prognostic factors such as disease pathology staging. Although the increased presence of F. nucleatum was associated with poorer prognosis in CRC patients, this may have limited clinical relevance as a prognostic biomarker.