Association of oxidative stress and inflammatory metabolites with Alzheimer's disease cerebrospinal fluid biomarkers in mild cognitive impairment.

BACKGROUND: Isoprostanes and prostaglandins are biomarkers for oxidative stress and inflammation. Their role in Alzheimer's disease (AD) pathophysiology is yet unknown. In the current study, we aim to identify the association of isoprostanes and prostaglandins with the Amyloid, Tau, Neurodegeneration (ATN) biomarkers (Aß-42, p-tau, and t-tau) of AD pathophysiology in mild cognitive impairment (MCI) subjects. METHODS: Targeted metabolomics profiling was performed using liquid chromatography-mass spectrometry (LCMS) in 147 paired plasma-CSF samples from the Ace Alzheimer Center Barcelona and 58 CSF samples of MCI patients from the Mannheim/Heidelberg cohort. Linear regression was used to evaluate the association of metabolites with CSF levels of ATN biomarkers in the overall sample and stratified by Aß-42 pathology and APOE genotype. We further evaluated the role of metabolites in MCI to AD dementia progression. RESULTS: Increased CSF levels of PGF2α, 8,12-iso-iPF2α VI, and 5-iPF2α VI were significantly associated (False discovery rate (FDR) < 0.05) with higher p-tau levels. Additionally, 8,12-iso-iPF2α VI was associated with increased total tau levels in CSF. In MCI due to AD, PGF2α was associated with both p-tau and total tau, whereases 8,12-iso-iPF2α VI was specifically associated with p-tau levels. In APOE stratified analysis, association of PGF2α with p-tau and t-tau was observed in only APOE ε4 carriers while 5-iPF2α VI showed association with both p-tau and t-tau in APOE ε33 carriers. CSF levels of 8,12- iso-iPF2α VI showed association with p-tau and t-tau in APOE ε33/APOE ε4 carriers and with t-tau in APOE ε3 carriers. None of the metabolites showed evidence of association with MCI to AD progression. CONCLUSIONS: Oxidative stress (8,12-iso-iPF2α VI) and inflammatory (PGF2α) biomarkers are correlated with biomarkers of AD pathology during the prodromal stage of AD and relation of PGF2α with tau pathology markers may be influenced by APOE genotype.

Prognostic value of molecular classification in stage IV endometrial cancer.

OBJECTIVES: Multiple studies have proven the prognostic value of molecular classification for stage I-III endometrial cancer patients. However, studies on the relevance of molecular classification for stage IV endometrial cancer patients are lacking. Hypothetically, poor prognostic molecular subtypes are more common in higher stages of endometrial cancer. Considering the poor prognosis of stage IV endometrial cancer patients, it is questionable whether molecular classification has additional prognostic value. Therefore, we determined which molecular subclasses are found in stage IV endometrial cancer and if there is a correlation with progression-free and overall survival. METHODS: A retrospective multicenter cohort study was conducted using data from five Dutch hospitals. Patients with stage IV endometrial cancer at diagnosis who were treated with primary cytoreductive surgery or cytoreductive surgery after induction chemotherapy between January 2000 and December 2018 were included. Exclusion criteria were age <18 years or recurrent disease. The molecular classification was performed centrally on all tumor samples according to the World Health Organization 2020 classification (including POLE and estrogen receptor status). The Kaplan-Meier method was used to calculate progression free and overall survival in the molecular subclasses, for the different histological subtypes and for estrogen receptor positive versus estrogen receptor negative tumors. Groups were compared using the log-rank test. RESULTS: 164 stage IV endometrial cancer patients were molecularly classified. Median age of the patients was 67 years (range 33-86). Most patients presented with a non-endometrioid histological subtype (58%). Intra-abdominal complete cytoreductive surgery was achieved in 60.4% of the patients. 101 tumors (61.6%) were classified as p53 abnormal, 35 (21.3%) as no specific molecular profile, 21 (12.8%) as mismatch repair deficient, and 6 (3%) as POLE mutated. Molecular classification had no significant impact on progression free (p=0.056) or overall survival (p=0.12) after cytoreductive surgery. Overall survival was affected by histologic subtype (p<0.0001) and estrogen receptor status (p=0.013). CONCLUSION: The distribution of the molecular subclasses in stage IV endometrial cancer patients differed substantially from the distribution in stage I-III endometrial cancer patients, with the unfavorable subclasses being more frequently present. Although the molecular classification was not prognostic in stage IV endometrial cancer, it could guide adjuvant treatment decisions.

Prehabilitation in colorectal cancer surgery improves outcome and reduces hospital costs.

INTRODUCTION: Increasing evidence suggests that multimodal prehabilitation programs reduce postoperative complication rates and length of stay. Nevertheless, prehabilitation is not standard care yet, also as financial consequences of such programs are lacking. Aim of this study was to analyse clinical outcomes and effects on hospital resources if prehabilitation is implemented for patients who are planned for colorectal surgery. MATERIALS AND METHODS: Patients undergoing elective colorectal surgery and who received either prehabilitation or standard care between January 2017 and March 2022 in a regional Dutch hospital were included. Outcome parameters were length of hospital stay, 30-day postoperative complications, 30-day ICU admission, readmission rates and hospital costs. RESULTS: A total of 196 patients completed prehabilitation whereas 390 patients received standard care. Lower overall complication rates (31 % vs 40 %, p = 0.04) and severe complication rates (20 % vs 31 %, p = 0.01) were observed in the prehabilitation group compared to standard care. Length of stay was shorter in the prehabilitation group (mean 5.80 days vs 6.71 days). In hospital cost savings were €1109 per patient, while the calculated investment for prehabilitation was €969. CONCLUSION: Implementation of a multimodal prehabilitation program in colorectal surgery reduces postoperative complication rates, length of stay and hospital costs.

Predictors of Long-Term Exercise Engagement in Patients With Obsessive-Compulsive Disorder: The Role of Physical Activity Enjoyment.

Most U.S. adults, even more so those with psychiatric conditions like obsessive-compulsive disorder (OCD), do not engage in the recommended amount of physical activity (PA), despite the wide array of physical and mental health benefits associated with exercise. Therefore, it is essential to identify mechanistic factors that drive long-term exercise engagement so they can be targeted. Using the science of behavior change (SOBC) framework, this study examined potential predictors of long-term exercise engagement as a first step towards identifying modifiable mechanisms, in individuals with OCD, such as PA enjoyment, positive or negative affect, and behavioral activation. Fifty-six low-active patients (mean age = 38.8 ±â€¯13.0, 64% female) with a primary diagnosis of OCD were randomized to either aerobic exercise (AE; n = 28) or health education (HE; n = 28), and completed measures of exercise engagement, PA enjoyment, behavioral activation, and positive and negative affect at baseline, postintervention, and 3-, 6-, and 12-month follow-up. Significant predictors of long-term exercise engagement up to 6-months postintervention were baseline PA (Estimate = 0.29, 95%CI [0.09, 0.49], p = .005) and higher baseline PA enjoyment (Estimate = 1.09, 95%CI [0.30, 1.89], p = .008). Change in PA enjoyment from baseline to postintervention was greater in AE vs. HE, t(44) = -2.06, p = .046, d = -0.61, but endpoint PA enjoyment did not predict follow-up exercise engagement above and beyond baseline PA enjoyment. Other hypothesized potential mechanisms (baseline affect or behavioral activation) did not significantly predict exercise engagement. Results suggest that PA enjoyment may be an important modifiable target mechanism for intervention, even prior to a formal exercise intervention. Next steps aligned with the SOBC framework are discussed, including examining intervention strategies to target PA enjoyment, particularly among individuals with OCD or other psychiatric conditions, who may benefit most from long-term exercise engagement's effects on physical and mental health.

Resolving the paradox of posttraumatic growth and event centrality in trauma survivors.

When a traumatic experience is central to an individual's identity and worldview, it can result in either severe posttraumatic stress disorder (PTSD) symptoms, perceived posttraumatic growth (PTG), or, paradoxically, both. To resolve this apparent paradox, we used network analytic methods to estimate the relations among components of event centrality (EC), PTSD symptoms, and PTG in 1,136 undergraduates who had experienced trauma. Participants completed surveys on their experiences with traumatic events as well as the degree to which they experienced PTSD symptoms, components of EC, and components of PTG. We performed network analysis to examine EC, PTSD, and PTG and identify which components of EC were most conducive to its associations with PTSD versus those with PTG. We found that the components of EC most associated with PTSD, the extent to which trauma serves as a script for the future, were markedly distinct from the components associated with PTG, the extent to which trauma is seen as a turning point in one's life. The combined findings suggest that EC may be a catalyst for subsequent positive or negative effects contingent upon how an individual interprets the centrality of their traumatic experience.

[Chlamydia mimics suspected ovarian cancer in a 21-year-old patient]. / Chlamydia-infectie imiteert ovariumcarcinoom.

BACKGROUND: The antigen CA125 is mainly known as a tumour marker in ovarian cancer, but may also be elevated in benign gynaecological disorders and non-gynaecological diseases. CASE DESCRIPTION: We examined a 21-year-old patient in the gynaecological oncology outpatient clinic, after she was referred with abnormal ovaries on ultrasound and a significantly elevated CA125. The patient had seen a gynaecologist four weeks earlier because of persistent abdominal pain, deep dyspareunia and vaginal bleeding after insertion of a Mirena IUD that has since been removed. The IUD turned out to be placed in the presence of an undiagnosed STD (Chlamydia), which seems to explain the abnormal ovaries and elevated tumour marker due to pelvic inflammatory disease (PID). CONCLUSION: PID can present atypically resembling ovarian carcinoma. Before inserting an IUD, evaluation of sexual history is essential to estimate the risk of an STI and, if necessary, to perform diagnostics.

Generation of a set of isogenic iPSC lines carrying all APOE genetic variants (Ɛ2/Ɛ3/Ɛ4) and knock-out for the study of APOE biology in health and disease.

APOE genotype is the strongest genetic risk factor for Alzheimer's Disease (AD). The low degree of homology between mouse and human APOE is a concerning issue in preclinical models currently used to study the role of this gene in AD pathophysiology. A key objective of ADAPTED (Alzheimer's Disease Apolipoprotein Pathology for Treatment Elucidation and Development) project was to generate in vitro models that better recapitulate human APOE biology. We describe a new set of induced pluripotent stem cells (iPSC) lines carrying common APOE variants (Ɛ2, Ɛ3, and Ɛ3/Ɛ4) and a knock-out isogenic to the parental APOE Ɛ4/Ɛ4 line (UKBi011-A).

Association of lysophosphatidic acids with cerebrospinal fluid biomarkers and progression to Alzheimer's disease.

BACKGROUND: Lysophosphatidic acids (LPAs) are bioactive signaling phospholipids that have been implicated in Alzheimer's disease (AD). It is largely unknown whether LPAs are associated with AD pathology and progression from mild cognitive impairment (MCI) to AD. METHODS: The current study was performed on cerebrospinal fluid (CSF) and plasma samples of 182 MCI patients from two independent cohorts. We profiled LPA-derived metabolites using liquid chromatography-mass spectrometry. We evaluated the association of LPAs with CSF biomarkers of AD, Aß-42, p-tau, and total tau levels overall and stratified by APOE genotype and with MCI to AD progression. RESULTS: Five LPAs (C16:0, C16:1, C22:4, C22:6, and isomer-LPA C22:5) showed significant positive association with CSF biomarkers of AD, Aß-42, p-tau, and total tau, while LPA C14:0 and C20:1 associated only with Aß-42 and alkyl-LPA C18:1, and LPA C20:1 associated with tau pathology biomarkers. Association of cyclic-LPA C16:0 and two LPAs (C20:4, C22:4) with Aß-42 levels was found only in APOE ε4 carriers. Furthermore, LPA C16:0 and C16:1 also showed association with MCI to AD dementia progression, but results did not replicate in an independent cohort. CONCLUSIONS: Our findings provide evidence that LPAs may contribute to early AD pathogenesis. Future studies are needed to determine whether LPAs play a role in upstream of AD pathology or are downstream markers of neurodegeneration.

CDH6 and HAGH protein levels in plasma associate with Alzheimer's disease in APOE ε4 carriers.

Many Alzheimer's disease (AD) genes including Apolipoprotein E (APOE) are found to be expressed in blood-derived macrophages and thus may alter blood protein levels. We measured 91 neuro-proteins in plasma from 316 participants of the Rotterdam Study (incident AD = 161) using Proximity Extension Ligation assay. We studied the association of plasma proteins with AD in the overall sample and stratified by APOE. Findings from the Rotterdam study were replicated in 186 AD patients of the BioFINDER study. We further evaluated the correlation of these protein biomarkers with total tau (t-tau), phosphorylated tau (p-tau) and amyloid-beta (Aß) 42 levels in cerebrospinal fluid (CSF) in the Amsterdam Dementia Cohort (N = 441). Finally, we conducted a genome-wide association study (GWAS) to identify the genetic variants determining the blood levels of AD-associated proteins. Plasma levels of the proteins, CDH6 (ß = 0.638, P = 3.33 × 10-4) and HAGH (ß = 0.481, P = 7.20 × 10-4), were significantly elevated in APOE ε4 carrier AD patients. The findings in the Rotterdam Study were replicated in the BioFINDER study for both CDH6 (ß = 1.365, P = 3.97 × 10-3) and HAGH proteins (ß = 0.506, P = 9.31 × 10-7) when comparing cases and controls in APOE ε4 carriers. In the CSF, CDH6 levels were positively correlated with t-tau and p-tau in the total sample as well as in APOE ε4 stratum (P < 1 × 10-3). The HAGH protein was not detected in CSF. GWAS of plasma CDH6 protein levels showed significant association with a cis-regulatory locus (rs111283466, P = 1.92 × 10-9). CDH6 protein is implicated in cell adhesion and synaptogenesis while HAGH protein is related to the oxidative stress pathway. Our findings suggest that these pathways may be altered during presymptomatic AD and that CDH6 and HAGH may be new blood-based biomarkers.

Ice-stream demise dynamically conditioned by trough shape and bed strength.

Ice sheet mass loss is currently dominated by fast-flowing glaciers (ice streams) terminating in the ocean as ice shelves and resting on beds below sea level. The factors controlling ice-stream flow and retreat over longer time scales (>100 years), especially the role of three-dimensional bed shape and bed strength, remain major uncertainties. We focus on a former ice stream where trough shape and bed substrate are known, or can be defined, to reconstruct ice-stream retreat history and grounding-line movements over 15 millennia since the Last Glacial Maximum. We identify a major behavioral step change around 18,500 to 16,000 years ago-out of tune with external forcing factors-associated with the collapse of floating ice sectors and rapid ice-front retreat. We attribute this step change to a marked geological transition from a soft/weak bed to a hard/strong bed coincident with a change in trough geometry. Both these factors conditioned and ultimately hastened ice-stream demise.

ß Cell GLP-1R Signaling Alters α Cell Proglucagon Processing after Vertical Sleeve Gastrectomy in Mice.

Bariatric surgery, such as vertical sleeve gastrectomy (VSG), causes high rates of type 2 diabetes remission and remarkable increases in postprandial glucagon-like peptide-1 (GLP-1) secretion. GLP-1 plays a critical role in islet function by potentiating glucose-stimulated insulin secretion; however, the mechanisms remain incompletely defined. Therefore, we applied a murine VSG model to an inducible ß cell-specific GLP-1 receptor (GLP-1R) knockout mouse model to investigate the role of the ß cell GLP-1R in islet function. Our data show that loss of ß cell GLP-1R signaling decreases α cell GLP-1 expression after VSG. Furthermore, we find a ß cell GLP-1R-dependent increase in α cell expression of the prohormone convertase required for the production of GLP-1 after VSG. Together, the findings herein reveal two concepts. First, our data support a paracrine role for α cell-derived GLP-1 in the metabolic benefits observed after VSG. Second, we have identified a role for the ß cell GLP-1R as a regulator of α cell proglucagon processing.

Good performance of p16/ki-67 dual-stained cytology for surveillance of women treated for high-grade CIN.

Women treated for high-grade cervical intraepithelial neoplasia (CIN) are at risk of recurrent CIN Grade 2 or worse (rCIN2+). Currently, posttreatment monitoring is performed using cytology or cytology/high-risk (hr)HPV cotesting. This study aimed to evaluate the performance of p16/Ki-67 dual-stained cytology (p16/Ki-67) for posttreatment monitoring. Three hundred and twenty-three women treated for high-grade CIN in the SIMONATH study underwent close surveillance by cytology, hrHPV and DNA methylation marker testing up to 12 months posttreatment. Histological endpoints were ascertained by colposcopy with biopsy at 6 and/or 12 months. p16/Ki-67 dual-staining was performed on residual liquid-based cytology samples obtained at, or shortly before biopsy collection. Clinical performance estimates of cytology, hrHPV, p16/Ki-67 testing and combinations thereof for the detection of rCIN2+ were determined and compared to each other. Sensitivity of p16/Ki-67 for rCIN2+ (69.2%) was nonsignificantly lower than that of cytology (82.1%; ratio 0.84, 95% CI: 0.71-1.01), but significantly lower than that of hrHPV testing (84.6%; ratio 0.82, 95% CI: 0.68-0.99). Specificity of p16/Ki-67 for rCIN2+ (90.4%) was significantly higher compared to both cytology (70.8%; ratio 1.28, 95% CI: 1.19-1.37) and hrHPV testing (76.2%; ratio 1.19, 95% CI: 1.12-1.26). Overall, hrHPV testing showed very high sensitivity, along with a good specificity. When considering cotesting, combined p16/Ki-67/hrHPV testing showed rCIN2+ sensitivity comparable to cytology/hrHPV cotesting (87.2% vs. 89.7%; ratio 0.97, 95% CI: 0.92-1.03), but with significantly increased specificity (74.2% vs. 58.1%; ratio 1.28, 95% CI: 1.19-1.38). Thus, when considered in combination with hrHPV, p16/Ki-67 might be an attractive approach for surveillance of women treated for high-grade CIN.

Determination of single cell lag times of Cronobacter spp. strains exposed to different stress conditions: Impact on detection.

The variability of stress resistance and lag time of single cells can have a big impact on their growth and therefore on the probability of their detection in food. In this study, six strains of Cronobacter spp. were subjected to heat, acid and desiccation stress and single cell lag times were determined using optical density measurements. The duration of lag time was highest after acid stress and did not correlate to stress resistance. The effect that the inactivation caused by stress and an extended lag time had on the projected cfu level reached after enrichment was simulated in different scenarios. For most strains, an enrichment time of 18h was sufficient for stressed cells to reach the suggested minimum level of cell inoculum for the Cronobacter screening broth detection. Particular strains may require longer recovery periods. Further, probability calculations showed that the number of samples taken from a batch may have an important effect on detection probability, especially at low contamination rates. Therefore, in addition to increasing the recovery period, increasing the number of samples is a suitable strategy to improve detection.

Effects of different media on the enrichment of low numbers of Shiga toxin-producing Escherichia coli in mung bean sprouts and on the development of the sprout microbiome.

Sprouted seeds have been implicated in a number of serious outbreaks caused by Salmonella and Shiga toxin-producing Escherichia coli. Sprouts pose a very complex challenge to bacterial pathogen enrichment and detection since they naturally contain high levels of background microflora including members of the Enterobacteriaceae. As such, the currently used method cannot ensure reliable detection of STEC in sprouts. In this study, we compared different media for the enrichment of Enterobacteriaceae in their ability to promote the growth of stressed STEC at 37°C and 42°C. Mung bean sprouts were spiked with low levels of STEC and their growth was recorded over time. In addition, the microbiome of mung bean sprouts was analysed before and after enrichment. Our results indicate that the growth of dry-stressed STEC is comparable in all of the tested enrichment media except for mTSB+Novobiocin and not influenced by the incubation temperature. Low levels of STEC spiked into the sprouts resuspended in media only grew to levels of around 4logcfu/ml during enrichment, which could reduce the probability of detection. Proteobacteria was the dominant phylum detected within the microbiome of non-enriched mung bean sprouts. During enrichment in EE-broth, Proteobacteria remained the most abundant phylum. In contrast, during enrichment in BPW the relative abundance of Proteobacteria decreased whereas Firmicutes increased when compared to the non-enriched mung bean sprout microbiome. The microbiome composition was not significantly influenced by the incubation temperature during enrichment in both BPW and EE-broth. This is the first study to examine the microbiome on sprouted mung bean seeds during BPW and EE enrichment and relates the bacterial community composition changes to the enrichment of pathogens.

Diagnostic value of the six-minute walk test (6MWT) in grown-up congenital heart disease (GUCH): Comparison with clinical status and functional exercise capacity.

BACKGROUND: Exercise testing for the assessment of functional capacity plays an important role in long-term follow-up of GUCH patients. CPX is the favored modality for decision-making recommended in the current guidelines. In contrast to this complex method, the 6 MWT is a simple, easy-to-perform, safe, and commonly available exercise test. Although well-established in various cardiopulmonary diseases, the diagnostic impact of the 6 MWT in GUCH patients is not known so far. METHODS: 102 GUCH patients were evaluated by 6 MWT and CPX simultaneously. Clinical symptoms were assessed, according to the NYHA classification. Additionally, an echocardiography study, and selected cardiac blood tests (N-terminal pro-brain natriuretic peptide (NT-proBNP), high-sensitive Troponin T) were performed. RESULTS: Ranges of six-minute walk distance (6 MWD) and peak oxygen consumption (peakVO2) were 116-765 m and 6.4-36.2 ml/kg/min, respectively. 6 MWD and peakVO2 showed a close correlation (r=0.72, 95% CI, 0.63 to 0.79). Patients with a peakVO2 of ≤ 15.5 ml/kg/min were excellently identified by 6 MWT (c-value=0.82). A cut-off value of 482 m was optimal to predict reduced peakVO2. In multivariate regression analysis, 6 MWD and NYHA class were identified as relevant predictors of peakVO2. In subgroup analysis, Eisenmenger patients achieved the shortest 6 MWD (280, SD 178 m). CONCLUSION: In our study population of GUCH patients, the 6 MWD shows a close correlation to peakVO2, and an excellent prediction of reduced peakVO2. Thus, it seems to be an easy-to-perform and reliable screening parameter to evaluate functional capacity of these patients (Controlled Clinical Trials number, NCT02193243).

Comparing the performance of FAM19A4 methylation analysis, cytology and HPV16/18 genotyping for the detection of cervical (pre)cancer in high-risk HPV-positive women of a gynecologic outpatient population (COMETH study).

Recently, DNA methylation analysis of FAM19A4 in cervical scrapes has been shown to adequately detect high-grade cervical intraepithelial neoplasia and cervical cancer (≥ CIN3) in high-risk HPV (hrHPV)-positive women. Here, we compared the clinical performance of FAM19A4 methylation analysis to cytology and HPV16/18 genotyping, separately and in combination, for ≥ CIN3 detection in hrHPV-positive women participating in a prospective observational multi-center cohort study. The study population comprised hrHPV-positive women aged 18-66 years, visiting a gynecological outpatient clinic. From these women, cervical scrapes and colposcopy-directed biopsies (for histological confirmation) were obtained. Cervical scrapes were analyzed for FAM19A4 gene promoter methylation, cytology and HPV16/18 genotyping. Methylation analysis was performed by quantitative methylation-specific PCR (qMSP). Sensitivities and specificities for ≥ CIN3 were compared between tests. Stratified analyses were performed for variables that potentially influence marker performance. Of all 508 hrHPV-positive women, the sensitivities for ≥ CIN3 of cytology, FAM19A4 methylation analysis, and cytology combined with HPV16/18 genotyping were 85.6, 75.6 and 92.2%, respectively, with corresponding specificities of 49.8, 71.1 and 29.4%, respectively. Both sensitivity and specificity of FAM19A4 methylation analysis were associated with age (p ≤ 0.001 each). In women ≥ 30 years (n = 287), ≥ CIN3 sensitivity of FAM19A4 methylation analysis was 88.3% (95%CI: 80.2-96.5) which was noninferior to that of cytology [85.5% (95%CI: 76.0-94.0)], at a significantly higher specificity [62.1% (95%CI: 55.8-68.4) compared to 47.6% (95%CI: 41.1-54.1)]. In conclusion, among hrHPV-positive women from an outpatient population aged ≥ 30 years, methylation analysis of FAM19A4 is an attractive marker for the identification of women with ≥ CIN3.

Evaluation of different buffered peptone water (BPW) based enrichment broths for detection of Gram-negative foodborne pathogens from various food matrices.

This study evaluated the effects of changing the composition of the pre-enrichment medium buffered peptone water (BPW) on the growth of stressed and unstressed Gram-negative foodborne pathogens in a one-broth enrichment strategy. BPW supplemented with an available iron source and sodium pyruvate, along with low levels of 8-hydroxyquinoline and sodium deoxycholate (BPW-S) improved the recovery of desiccated Cronobacter spp. from powdered infant formula. Growth of Salmonella and STEC was comparable in all BPW variants tested for different food matrices. In products with high levels of Gram-negative background flora (e.g. sprouts), the target organisms could not be reliably detected by PCR in any of the BPW variants tested unless the initial level exceeded 10(3) cfu/10 g of sprouts. Based on these results we suggest BPW-S for a one-broth enrichment strategy of stressed Gram-negative foodborne pathogens from dry products. However, a one-broth enrichment strategy based on BPW variants tested in this evaluation is not recommended for produce with a high level of Gram-negative background flora due to very high detection limits.