Vaginal dysbiosis seems associated with hrHPV infection in women attending the Dutch Cervical Cancer Screening Program.

Human papillomavirus (HPV) is a sexually transmitted virus, which infects approximately 80% of all men and women at some time in their lives. Usually, the infection is resolved successfully by the body's immune system. Persistent infection with high-risk HPV (hrHPV) is necessary but not sufficient for cervical cancer development, and additional factors, such as the vaginal microbiome (vaginome), are thought to be involved. The aim of this study is to investigate whether either vaginal dysbiosis (imbalance in vaginal bacterial composition) or sexually transmitted pathogens, e.g., Chlamydia trachomatis (CT), are possible cofactors for hrHPV infection and HPV-induced cervical dysplasia in asymptomatic women attending the Dutch Cervical Cancer Screening Program. In this study, 492 hrHPV-positive and 500 hrHPV-negative cervical smears from women attending the Screening Program were included. Age and cytology were known for the hrHPV-positive samples. All cervical smears were diluted in Aptima® specimen transfer medium and tested with Aptima® transcription-mediated amplification assays targeting CT, Neisseria gonorrhoeae (NG), Mycoplasma genitalium (MG), Candida spp. (CS), C. glabrata (CG), Trichomonas vaginalis (TV), and bacterial vaginosis (BV). The prevalences of CT, NG, MG, CS, CG, TV, and BV in this cohort were found to be 1.9%, 0.0%, 1.7%, 5.4%, 1.4%, 0.1%, and 27.2%, respectively. When comparing HPV groups, it was found that CT, MG, and BV had a significantly higher prevalence in hrHPV-positive smears as compared with hrHPV-negative samples (for all p < 0.001). No significant differences were found when comparing different age groups and cytology outcomes. In conclusion, vaginal dysbiosis seems associated with hrHPV infection in women attending the Dutch Cervical Cancer Screening Program.

Trends in molecular diagnostics: 12th European Meeting on Molecular Diagnostics, Noordwijk aan Zee, the Netherlands, 12-14 October 2022.

This report provides an overview of the highlights of the 12th European Meeting on Molecular Diagnostics held in Noordwijk aan Zee, The Netherlands, 12-14 October 2022. This 3-day conference covered many relevant topics in the field of molecular diagnostics in humans i.e. oncology, infectious diseases, laboratory medicine, pharmacogenetics, pathology, and preventive medicine. Other relevant topics included quality management, laboratory automation, diagnostic preparedness, and lessons learned from the COVID pandemic. More than 400 participants, the majority coming from European countries, attended the meeting. Besides high-quality scientific presentations, more than 40 diagnostic companies presented their latest innovations, altogether in an informal and inspiring ambiance.

Reclassification of diffuse large B cell lymphoma to large B cell lymphoma with IRF4 rearrangement in an adult population.

AIMS: Large B cell lymphoma with IRF4 rearrangement (LBCL-IRF4) is a new entity in the 2017 revised World Health Organisation (WHO) classification that was initially mainly reported in children. After identification of a 79-year-old patient, we assessed how often IRF4 rearrangements can be detected in adult diffuse large B cell lymphomas (DLBCLs) which have to be reclassified to LBCL-IRF4 based on fluorescence in-situ hybridisation (FISH) for IRF4. METHODS AND RESULTS: With FISH, we studied the presence of IRF4 rearrangements in 238 lymphomas that were diagnosed as DLBCL according to the previous WHO classification of 2008. CONCLUSIONS: In addition to the index patient, an IRF4 rearrangement was detected in another five of 237 patients (2%). The immunohistochemical profile of these five IRF4 rearranged lymphomas was consistent with previous reports of LBCL-IRF4. One case was recognised to represent transformation of follicular lymphoma rather than de-novo LBCL-IRF4. BCL6 rearrangements were found in two cases of LBCL-IRF4; BCL2 and MYC rearrangements were excluded. Patients presented with limited stage disease with involvement of the head and neck in three patients, and involvement of the lung and thyroid in two others. This study shows that, although rare, LBCL-IRF4 should also be considered in older patients and at localisations other than the head and neck region.

Sociodemographic Characteristics and Screening Outcomes of Women Preferring Self-Sampling in the Dutch Cervical Cancer Screening Programme: A Population-Based Study.

BACKGROUND: In the Netherlands, lower high-risk human papillomavirus (hrHPV) positivity but higher cervical intraepithelial neoplasia (CIN) 2+ detection were found in self-collected compared with clinician-collected samples. To investigate the possible reason for these differences, we compared sociodemographic and screening characteristics of women and related these to screening outcomes. METHODS: We extracted data from PALGA on all primary hrHPV screens and associated follow-up tests for 857,866 screened women, invited in 2017 and 2018. We linked these data with sociodemographic data from Statistics Netherlands. Logistic regression was performed for hrHPV positivity and CIN 2+/3+ detection. RESULTS: Out of the 857,866 women, 6.8% chose to use a self-sampling device. A higher proportion of self-sampling users was ages 30 to 35 years, was not previously screened, was living in a one-person household, or was the breadwinner in the household. After adjustment for these factors self-sampling had lower hrHPV positivity (aOR, 0.65; 95% CI, 0.63-0.68)) as compared with clinician-collected sampling, as well as lower odds of CIN 2+ (aOR, 0.76; 95% CI, 0.70-0.82) and CIN 3+ (aOR, 0.86; 95% CI, 0.78-0.95) detection. CONCLUSIONS: It is likely that the observed differences between the two sampling methods are not only related to sociodemographic differences, but related to differences in screening test accuracy and/or background risk. IMPACT: Self-sampling can be used for targeting underscreened women, as a more convenient screening tool. Further investigation is required to evaluate how to implement self-sampling, when it is used as a primary instrument in routine screening. See related commentary by Arbyn et al., p. 159.

Comprehensive analytical and clinical evaluation of a RNA extraction-free saliva-based molecular assay for SARS-CoV-2.

Standard SARS-CoV-2 testing protocols using nasopharyngeal/throat (NP/T) swabs are invasive and require trained medical staff for reliable sampling. In addition, it has been shown that PCR is more sensitive as compared to antigen-based tests. Here we describe the analytical and clinical evaluation of our in-house RNA extraction-free saliva-based molecular assay for the detection of SARS-CoV-2. Analytical sensitivity of the test was equal to the sensitivity obtained in other Dutch diagnostic laboratories that process NP/T swabs. In this study, 955 individuals participated and provided NP/T swabs for routine molecular analysis (with RNA extraction) and saliva for comparison. Our RT-qPCR resulted in a sensitivity of 82,86% and a specificity of 98,94% compared to the gold standard. A false-negative ratio of 1,9% was found. The SARS-CoV-2 detection workflow described here enables easy, economical, and reliable saliva processing, useful for repeated testing of individuals.

Clinical performance of high-risk HPV testing on self-samples versus clinician samples in routine primary HPV screening in the Netherlands: An observational study.

BACKGROUND: High-risk human papillomavirus (hrHPV) testing on self-collected samples has potential as a primary screening tool in cervical screening, but real-world evidence on its accuracy in hrHPV-based screening programmes is lacking. METHODS: In the Netherlands, women aged 30-60 years invited for cervical screening can choose between sampling at the clinician's office (Cervex Brush) or self-sampling at home (Evalyn Brush). HrHPV testing is performed using Roche Cobas 4800. We collected screening test results between January 2017 and March 2018 and histological follow-up until August 2019. The main outcome measures were mean cycle threshold (Ct) value, cervical intraepithelial neoplasia (CIN) grade 3 or cancer (CIN3+) and CIN grade 2 or worse (CIN2+). FINDINGS: 30,808 women had a self-collected and 456,207 had a clinician-collected sample. In hrHPV-positive women with adequate cytology, Ct values were higher for self-collection than clinician-collection with a mean Ct difference of 1·25 (95% CI 0·98-1·52) in women without CIN2+, 2·73 (1·75-3·72) in CIN2 and 3·59 (3·03-4·15) in CIN3+. The relative sensitivity for detecting CIN3+ was 0·94 (0·90-0·97) for self-collection versus clinician-collection and the relative specificity was 1·02 (1·02-1·02). INTERPRETATION: The clinical accuracy of hrHPV testing on a self-collected sample for detection of CIN3+ is high and supports its use as a primary screening test for all invited women. Because of the slightly lower sensitivity of hrHPV testing on a self-collected compared to a clinician-collected sample, an evaluation of the workflow procedure to optimise clinical performance seems warranted. FUNDING: National Institute for Public Health and the Environment (the Netherlands) and the European Commission.

Time dependent effect of cold ischemia on the phosphoproteome and protein kinase activity in fresh-frozen colorectal cancer tissue obtained from patients.

BACKGROUND: Based on their potential to analyze aberrant cellular signaling in relation to biological function, kinase activity profiling in tumor biopsies by peptide microarrays and mass spectrometry-based phosphoproteomics may guide selection of protein kinase inhibitors in patients with cancer. Variable tissue handling procedures in clinical practice may influence protein phosphorylation status and kinase activity and therewith may hamper biomarker discovery. Here, the effect of cold ischemia time (CIT) on the stability of kinase activity and protein phosphorylation status in fresh-frozen clinical tissue samples was studied using peptide microarrays and mass spectrometry-based phosphoproteomics. METHODS: Biopsies of colorectal cancer resection specimens from five patients were collected and snap frozen immediately after surgery and at 6 additional time points between 0 and 180 min of CIT. Kinase activity profiling was performed for all samples using a peptide microarray. MS-based global phosphoproteomics was performed in tumors from 3 patients at 4 time points. Statistical and cluster analyses were performed to analyze changes in kinase activity and phosphoproteome resulting from CIT. RESULTS: Unsupervised cluster analysis of kinase activity and phosphoproteome data revealed that samples from the same patients cluster together. Continuous ANOVA analysis of all 7 time points for 5 patient samples resulted in 4 peptides out of 210 (2%) with significantly (p < 0.01 and fold change > 2) altered signal intensity in time. In 4 out of 5 patients tumor kinase activity was stable with CIT. MS-based phosphoproteomics resulted in the detection of 10,488 different phosphopeptides with on average 6044 phosphopeptides per tumor sample. 2715 phosphopeptides were detected in all samples at time point 0, of which 90 (3.3%) phosphopeptides showed significant changes in intensity with CIT (p < 0.01). Only two phosphopeptides were significantly changed in all time points, including one peptide (PKP3) with a fold change > 2. CONCLUSIONS: The vast majority of the phosphoproteome as well as the activity of protein kinases in colorectal cancer resection tissue is stable up to 180 min of CIT and reflects tumor characteristics. However, specific changes in kinase activity with increasing CIT were observed. Therefore, stringent tissue collection procedures are advised to minimize changes in kinase activity during CIT.

Performance analysis of high-throughput HPV testing on three automated workflows.

Primary high-risk human papillomavirus (hrHPV) DNA testing has been introduced in several countries worldwide, including The Netherlands. The objective of this study was to compare three automated workflow procedures for hrHPV testing of which the hrHPV detection assays meet the international guidelines for HPV testing. To mimic a realistic screening situation, we aimed to process 15 000 residual PreservCyt cervical samples in a period of 3 months. During a 3 months period, four technicians were involved in processing 5000 specimens per month on three automated platforms, (1) Qiagen Digene® HC2 HPV DNA test (HC2, signal amplification); (2) Roche Cobas® HPV test (DNA amplification), and (3) Hologic Aptima® HPV test (RNA amplification). We measured and scored general aspects (time-to-results, hands-on-time (HOT)), maintenance, pre-run, run and post-run aspects, inventory (orders, storage), and number of errors on a scale from 1 to 10. As determined for one complete workflow each, maximum processing capacity and HOT were 296 samples and 2 h:55 m, 282 samples and 3 h:20 m, and 264 samples and 4 h:15 m for Aptima, Cobas, and HC2, respectively. The mean throughput time per run was 5 h:51 m for Cobas in which 94 samples could be processed. For Aptima, the mean throughput time per run was 6 h:30 m for 60 samples. Mean throughput time for HC2 is longer since results were provided on day 2. In this study, the fully automated Aptima workflow scores best with a 7.2, followed by Cobas with a score of 7.1 and HC2 with a score of 5.8. Although all HPV tests used in this comparison meet the international test guidelines, the performance (workflow) characteristics of the assays vary widely. A specific choice of a laboratory for high-throughput testing can be different based on the laboratory's demands, but also hands-on-time, time-to-results/ # samples, maintenance, pre-run, run and post-run parameters, consumables, technical support, and number of errors are important operational factors for the selection of a fully automated workflow for hrHPV testing.

Introduction of primary screening using high-risk HPV DNA detection in the Dutch cervical cancer screening programme: a population-based cohort study.

BACKGROUND: In January 2017, the Dutch cervical cancer screening programme transitioned from cytomorphological to primary high-risk HPV (hrHPV) DNA screening, including the introduction of self-sampling, for women aged between 30 and 60 years. The Netherlands was the first country to switch to hrHPV screening at the national level. We investigated the health impact of this transition by comparing performance indicators from the new hrHPV-based programme with the previous cytology-based programme. METHODS: We obtained data from the Dutch nationwide network and registry of histo- and cytopathology (PALGA) for 454,573 women eligible for screening in 2017 who participated in the hrHPV-based programme between 1 January 2017 and 30 June 2018 (maximum follow-up of almost 21 months) and for 483,146 women eligible for screening in 2015 who participated in the cytology-based programme between 1 January 2015 and 31 March 2016 (maximum follow-up of 40 months). We compared indicators of participation (participation rate), referral (screen positivity; referral rate) and detection (cervical intraepithelial neoplasia (CIN) detection; number of referrals per detected CIN lesion). RESULTS: Participation in the hrHPV-based programme was significantly lower than that in the cytology-based programme (61% vs 64%). Screen positivity and direct referral rates were significantly higher in the hrHPV-based programme (positivity rate: 5% vs 9%; referral rate: 1% vs 3%). CIN2+ detection increased from 11 to 14 per 1000 women screened. Overall, approximately 2.2 times more clinical irrelevant findings (i.e. ≤CIN1) were found in the hrHPV-based programme, compared with approximately 1·3 times more clinically relevant findings (i.e. CIN2+); this difference was mostly due to a national policy change recommending colposcopy, rather than observation, of hrHPV-positive, ASC-US/LSIL results in the hrHPV-based programme. CONCLUSIONS: This is the first time that comprehensive results of nationwide implementation of hrHPV-based screening have been reported using high-quality data with a long follow-up. We have shown that both benefits and potential harms are higher in one screening round of a well-implemented hrHPV-based screening programme than in an established cytology-based programme. Lower participation in the new hrHPV programme may be due to factors such as invitation policy changes and the phased roll-out of the new programme. Our findings add further to evidence from trials and modelling studies on the effectiveness of hrHPV-based screening.

Soluble mannose receptor levels in blood correlate to disease severity in patients with community-acquired pneumonia.

PURPOSE: Community-acquired pneumonia (CAP) is the most common form of pneumonia and is a leading infectious cause worldwide. Identification of patients that are at risk to develop severe disease has proven to be a major challenge. Soluble mannose receptor (sMR; sCD206) is a new serum marker for macrophage activation. Recent studies showed that sMR levels are increased in patients suffering from severe infections making it a potential biomarker for improved discrimination of disease severity. For measuring sMR, no standardized assay is available. Aim of this study is to develop an assay for standardized measurement of sMR. Next, this assay was used to assess sMR plasma levels for its ability to predict severe disease development in a patient cohort for community-acquired pneumonia. METHODS: We developed a well-validated sandwich ELISA that enables standardized measurement of sMR in plasma and serum samples. Repeatability was tested by calculating the percentage coefficient of variation (%CV) within and between runs and within and between operators. sMR levels were assessed in a cohort of 100 patients with community-acquired pneumonia. RESULTS: All %CV values were <10%, indicating low variation. Higher sMR levels were observed in patients with severe disease when compared to patients without severe disease development (p = 0.004). Patients with sMR levels between 100-430 ng/ml had 22.7% chance to develop severe disease whereas patients with levels between 430-1000 ng/ml had 33.3% chance to develop severe disease. CONCLUSIONS: We suggest that sMR has potential as a new biomarker for the prediction of disease severity in patients with community-acquired pneumonia.

Sexual inactivity and occurrence of STIs in relation to weight status in women: Two large population-based studies.

The aim of this study was to examine sexual inactivity and occurrence of selected sexually transmitted infections in relation to body mass index. We used data from two large Danish population-based cross-sectional studies conducted in 1991-1995 (HPV study: 6869 women, aged 22-32 years) and in 2004-2005 (Liva study: 19,484 women, aged 18-45 years). Data were collected using a structured interview and measured weight, height, high-risk human papillomavirus DNA, Chlamydia DNA for the HPV study and a structured questionnaire for the Liva study. Overweight and obese women were more likely to have had no lifetime sexual partner or no sexual partner in the last year, e.g., obese women had a threefold (95 percent CI: 1.95-5.04) odds ratio of having had no sexual partner in the last year compared to normal weight women. Additionally, overweight and obese women had a lower likelihood of genital warts and high-risk human papillomavirus infection. A similar tendency was found for self-reported Chlamydia, but not with presence of Chlamydia DNA. If higher likelihood of no lifetime or recent sexual partners among overweight and obese women reflects unmet sexual needs, it could give rise to concern because quality of sexual life is associated with general quality of life.

Multidisciplinary molecular diagnostics: the 9th European meeting on molecular diagnostics.

This report presents a summary of the 9th European Meeting on Molecular Diagnostics held in Noordwijk, The Netherlands, 14-16 October 2015. This 3-day conference covered many relevant topics in the field of molecular diagnostics in humans, including infectious disease, oncology, outbreak management, population-based cancer screening, standardization and quality control, chronic diseases and pharmacogenetics. Beyond these different areas, shared values are new technologies and novel technical and clinical applications. Approximately 450 participants, the majority coming from European countries, attended the meeting. Besides high quality scientific presentations, more than 35 diagnostic companies presented their latest innovations, altogether in an informal and inspiring scientific ambience.

Risk Factors for Incident and Redetected Chlamydia trachomatis Infection in Women: Results of a Population-Based Cohort Study.

OBJECTIVES: To investigate risk factors for incident and redetected Chlamydia trachomatis (CT) infection in women, including the role of high-risk human papillomavirus (HPV). METHODS: In this population-based, prospective cohort study conducted in Copenhagen, Denmark, 10,729 women aged 20 to 29 years were tested for CT and HPV DNA and provided information on sexual and health behavior at baseline. Of these, 7998 (74.5%) participated in a follow-up visit 2 years later with identical data collection. We used logistic regression to investigate risk factors for incident and redetected CT infection at follow-up. RESULTS: Among CT DNA negative women at baseline (n = 7529), 106 (1.4%) were CT DNA positive at follow-up (incident infection). Increasing number of sexual partners during follow-up (odds ratio [OR], 1.07 per partner; 95% confidence interval (CI), 1.02-1.11), low educational level (OR, 1.69; 95% CI, 1.11-2.56; for basic education vs. high school or higher), and high-risk HPV positivity at baseline (OR, 1.66; 95% CI, 1.06-2.58) were risk factors for incident infection, whereas older age (OR, 0.86 per year increase; 95% CI, 0.80-0.93) and condom use (OR, 0.60; 95% CI, 0.38-0.94) were associated with reduced risk. Among CT DNA positive women at baseline (n = 469), 108 (23.0%) tested positive at follow-up (redetected infection). We found no statistically significant associations between age, educational level, sexual behavior, smoking, or high-risk HPV status and the risk for redetected CT. CONCLUSION: Young age, low educational level, high number of sexual partners, failure to use condoms, and high-risk HPV positivity are associated with increased risk for incident CT infection. These findings may guide the development of targeted CT prevention strategies, including screening and information campaigns.

Allelic imbalance at the HER2/TOP2A locus in breast cancer.

BACKGROUND: Breast cancer is a heterogeneous disease with various histological features and molecular markers. These are utilized for the prediction of clinical outcome and therapeutic decision making. In addition to well established markers such as HER2 overexpression and estrogen and progesterone receptor (ER and PR) status, chromosomal instability is evolving as an important hallmark of cancers. The HER2/TOP2A locus is of great importance in breast cancer. The copy number variability at this locus has been proposed to be a marker for the degree of chromosomal instability. We therefore developed a Single Nucleotide Polymorphism (SNP) assay to evaluate allelic imbalance at the HER2/TOP2A locus in three different entities of primary breast tumors. METHODS: Eleven SNPs were carefully selected and detected by real time PCR using DNA extracted from paired (histologically normal and tumor) paraffin-embedded tissues. Primary breast tumors of 44 patients were included, 15 tumors with HER2 overexpression, 16 triple negative tumors, defined by the absence of HER2 overexpression and a negative ER and PR status and 13 ER and PR positive tumors without HER2 overexpression. As controls, histologically normal breast tissues from 10 patients with no breast tumor were included. RESULTS: Allelic imbalance was observed in 13/15 (87 %) HER2 positive tumors, the remaining 2 being inconclusive. Of the 16 triple negative tumors, 12 (75 %) displayed instability, 3 (19 %) displayed no instability, and 1 was inconclusive. Of the 13 hormone receptor positive tumors, 5 (38 %) displayed allelic imbalance, while 8 did not. CONCLUSIONS: We conclude that the SNP assay is suitable for rapid testing of allelic (im)balance at the HER2/TOP2A locus using paraffin-embedded tissues. Based on allelic imbalance at this locus, both triple negative and ER and PR positive breast tumors can be subcategorized. The clinical relevance of the allelic (im)balance status at the HER2/TOP2A locus in breast cancer is subject of future study. VIRTUAL SLIDES: The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/2086062232155220.

Chlamydia trachomatis and risk of cervical intraepithelial neoplasia grade 3 or worse in women with persistent human papillomavirus infection: a cohort study.

OBJECTIVES: Some studies suggest that Chlamydia trachomatis (CT) enhances cervical carcinogenesis; however, a possible confounding effect of persistent human papillomavirus (HPV) infection was not addressed. We examined the potential role of CT infection in the development of subsequent cervical intraepithelial neoplasia grade 3 or worse (CIN3+) in women with prevalent HPV infection and in a subgroup of women with persistent HPV infection. METHODS: Participants in this population-based cohort study underwent a structured interview, including history of CT infection, and subsequently cervical exfoliated cells were obtained for HPV DNA and CT DNA testing. Women with high-risk HPV DNA infection and no prevalent cervical disease constituted the overall study population (n=1390). A subgroup of women with persistent HPV infection (n=320) was also identified. All women were passively followed for development of cervical lesions in the national Pathology Data Bank. HRs and 95% CIs for CIN3+ during follow-up (up to 19 years) were estimated in an accelerated failure time model. RESULTS: Women who reported more than one CT infection had a statistically significantly increased risk of CIN3+ (high-risk HPV-positive, HR=2.51, 95% CI 1.44 to 4.37) (persistent HPV infection, HR=3.65, 95% CI 1.53 to 8.70). We found no association between CT DNA and subsequent risk of CIN3+ among women who were HPV-positive or had a persistent HPV infection at baseline. CONCLUSIONS: Repeated CT infections increased the risk of CIN3+ among women with prevalent as well as persistent high-risk HPV infection.

Biomarkers and molecular analysis to improve bloodstream infection diagnostics in an emergency care unit.

Molecular pathogen detection from blood is still expensive and the exact clinical value remains to be determined. The use of biomarkers may assist in preselecting patients for immediate molecular testing besides blood culture. In this study, 140 patients with ≥ 2 SIRS criteria and clinical signs of infection presenting at the emergency department of our hospital were included. C-reactive protein (CRP), neutrophil-lymphocyte count ratio (NLCR), procalcitonin (PCT) and soluble urokinase plasminogen activator receptor (suPAR) levels were determined. One ml EDTA blood was obtained and selective pathogen DNA isolation was performed with MolYsis (Molzym). DNA samples were analysed for the presence of pathogens, using both the MagicPlex Sepsis Test (Seegene) and SepsiTest (Molzym), and results were compared to blood cultures. Fifteen patients had to be excluded from the study, leaving 125 patients for further analysis. Of the 125 patient samples analysed, 27 presented with positive blood cultures of which 7 were considered to be contaminants. suPAR, PCT, and NLCR values were significantly higher in patients with positive blood cultures compared to patients without (p < 0.001). Receiver operating characteristic curves of the 4 biomarkers for differentiating bacteremia from non-bacteremia showed the highest area under the curve (AUC) for PCT (0.806 (95% confidence interval 0.699-0.913)). NLCR, suPAR and CRP resulted in an AUC of 0.770, 0.793, and 0.485, respectively. When compared to blood cultures, the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for SepsiTest and MagicPlex Sepsis Test were 11%, 96%, 43%, 80%, and 37%, 77%, 30%, 82%, respectively. In conclusion, both molecular assays perform poorly when one ml whole blood is used from emergency care unit patients. NLCR is a cheap, fast, easy to determine, and rapidly available biomarker, and therefore seems most promising in differentiating BSI from non-BSI patients for subsequent pathogen identification using molecular diagnostics.

Comparison of pathogen DNA isolation methods from large volumes of whole blood to improve molecular diagnosis of bloodstream infections.

For patients suffering from bloodstream infections (BSI) molecular diagnostics from whole blood holds promise to provide fast and adequate treatment. However, this approach is hampered by the need of large blood volumes. Three methods for pathogen DNA isolation from whole blood were compared, i.e. an enzymatic method (MolYsis, 1-5 ml), the novel non-enzymatic procedure (Polaris, 1-5 ml), and a method that does not entail removal of human DNA (Triton-Tris-EDTA EasyMAG, 200 µl). These methods were evaluated by processing blood spiked with 0-1000 CFU/ml of Staphylococcus aureus, Pseudomonas aeruginosa and Candida albicans. Downstream detection was performed with real-time PCR assays. Polaris and MolYsis processing followed by real-time PCRs enabled pathogen detection at clinically relevant concentrations of 1-10 CFU/ml blood. By increasing sample volumes, concurrent lower cycle threshold (Ct) values were obtained at clinically relevant pathogen concentrations, demonstrating the benefit of using larger blood volumes. A 100% detection rate at a concentration of 10 CFU/ml for all tested pathogens was obtained with the Polaris enrichment, whereas comparatively lower detection rates were measured for MolYsis (50-67%) and EasyMAG (58-79%). For the samples with a concentration of 1 CFU/ml Polaris resulted in most optimal detection rates of 70-75% (MolYsis 17-50% and TTE-EasyMAG 20-36%). The Polaris method was more reproducible, less labour intensive, and faster (45 minutes (including Qiagen DNA extraction) vs. 2 hours (MolYsis)). In conclusion, Polaris and MolYsis enrichment followed by DNA isolation and real-time PCR enables reliable and sensitive detection of bacteria and fungi from 5 ml blood. With Polaris results are available within 3 hours, showing potential for improved BSI diagnostics.