Culture-independent identification of bloodstream infections from whole blood: prospective evaluation in specimens of known infection status.

Sepsis caused by bloodstream infection (BSI) is a major healthcare burden and a leading cause of morbidity and mortality worldwide. Timely diagnosis is critical to optimize clinical outcome, as mortality rates rise every hour treatment is delayed. Blood culture remains the "gold standard" for diagnosis but is limited by its long turnaround time (1-7 days depending on the organism) and its potential to provide false-negative results due to interference by antimicrobial therapy or the presence of mixed (i.e., polymicrobial) infections. In this paper, we evaluated the performance of resistance and pathogen ID/BSI, a direct-from-specimen molecular assay. To reduce the false-positivity rate common with molecular methods, this assay isolates and detects genomic material only from viable microorganisms in the blood by incorporating a novel precursor step to selectively lyse host and non-viable microbial cells and remove cell-free genomic material prior to lysis and analysis of microbial cells. Here, we demonstrate that the assay is free of interference from host immune cells and common antimicrobial agents at elevated concentrations. We also demonstrate the accuracy of this technology in a prospective cohort pilot study of individuals with known sepsis/BSI status, including samples from both positive and negative individuals. IMPORTANCE: Blood culture remains the "gold standard" for the diagnosis of sepsis/bloodstream infection (BSI) but has many limitations which may lead to a delay in appropriate and accurate treatment in patients. Molecular diagnostic methods have the potential for markedly improving the management of such patients through faster turnaround times and increased accuracy. But molecular diagnostic methods have not been widely adopted for the identification of BSIs. By incorporating a precursor step of selective lysis of host and non-viable microorganisms, our resistance and pathogen ID (RaPID)/BSI molecular assay addresses many limitations of blood culture and other molecular assay. The RaPID/BSI assay has an approximate turnaround time of 4 hours, thereby significantly reducing the time to appropriate and accurate diagnosis of causative microorganisms in such patients. The short turnaround time also allows for close to real-time tracking of pathogenic clearance of microorganisms from the blood of these patients or if a change of antimicrobial regimen is required. Thus, the RaPID/BSI molecular assay helps with optimization of antimicrobial stewardship; prompt and accurate diagnosis of sepsis/BSI could help target timely treatment and reduce mortality and morbidity in such patients.

Plasma soluble fms-like tyrosine kinase 1 to placental growth factor ratio of 11.5 multiples of median predicts preeclampsia with severe features within 2 weeks of testing.

BACKGROUND: Angiogenic imbalances, characterized by an excess of antiangiogenic factors (soluble fms-like tyrosine kinase 1) and reduced angiogenic factors (vascular endothelial growth factor and placental growth factor), contribute to the mechanisms of disease in preeclampsia. The ratio of soluble fms-like tyrosine kinase 1 to placental growth factor has been used as a biomarker for preeclampsia, but the cutoff values may vary with gestational age and assay platform. OBJECTIVE: This study aimed to compare multiples of the median of the maternal plasma soluble fms-like tyrosine kinase 1 to placental growth factor ratio, soluble fms-like tyrosine kinase 1, placental growth factor, and conventional clinical and laboratory values in their ability to predict preeclampsia with severe features. STUDY DESIGN: We conducted a cohort study across 18 United States centers involving hospitalized individuals with hypertension between 23 and 35 weeks' gestation. Receiver operating characteristic curve analyses of maternal plasma biomarkers, highest systolic or diastolic blood pressures, and laboratory values at enrollment were performed for the prediction of preeclampsia with severe features. The areas under the curve were compared, and quasi-Poisson regression models were fitted to estimate relative risks. The primary outcome was preeclampsia with severe features within 2 weeks of enrollment. Secondary outcomes were a composite of severe adverse maternal outcomes (elevated liver enzymes, low platelets count, placental abruption, eclampsia, disseminated intravascular coagulation, and pulmonary edema) and a composite of severe adverse perinatal outcomes (birth weight below the third percentile, very preterm birth [<32 weeks' gestation], and fetal or neonatal death). RESULTS: Of the 543 individuals included in the study, preeclampsia with severe features within 2 weeks was observed in 33.1% (n=180) of them. A receiver operating characteristic curve-derived cutoff of 11.5 multiples of the median for the soluble fms-like tyrosine kinase 1 to placental growth factor plasma ratio provided good sensitivity (90.6%), specificity (76.9%), positive predictive value (66.0%), negative predictive value (94.3%), positive likelihood ratio (3.91), negative likelihood ratio (0.12), and accuracy (81.4%) for preeclampsia with severe features within 2 weeks. This cutoff was used to compare test positive cases (≥ cutoff) and test negative cases (< cutoff). Preeclampsia with severe features (66.0% vs 5.7%; P<.001) and composites of severe adverse maternal (8.11% vs 2.7%; P=.006) or perinatal (41.3% vs 10.14%; P=.001) outcomes within 2 weeks were more frequent in test positive cases than in test negative cases. A soluble fms-like tyrosine kinase 1 to placental growth factor plasma ratio ≥11.5 multiples of the median was independently associated with preeclampsia with severe features (adjusted incidence rate ratio, 9.08; 95% confidence interval, 6.11-14.06; P<.001) and a composite of severe adverse perinatal outcomes (adjusted incidence rate ratio, 9.42; 95% confidence interval, 6.36-14.53; P<.001) but not with a composite of severe adverse maternal outcomes (adjusted incidence rate ratio, 2.20; 95% confidence interval, 0.95-5.54; P=.08). The area under the curve for the soluble fms-like tyrosine kinase 1 to placental growth factor plasma ratio in multiples of the median (0.91; 95% confidence interval, 0.89-0.94) for preeclampsia with severe features within 2 weeks was significantly higher (P<.001 for all comparisons) than either plasma biomarker alone or any other parameter with the exception of absolute soluble fms-like tyrosine kinase 1 to placental growth factor plasma ratio values. CONCLUSION: A soluble fms-like tyrosine kinase 1 to placental growth factor plasma ratio ≥11.5 multiples of the mean among hospitalized patients with hypertension between 23 and 35 week's gestation predicts progression to preeclampsia with severe features and severe adverse perinatal outcomes within 2 weeks.

Longitudinal expression of Toll-like receptors on dendritic cells in uncomplicated pregnancy and postpartum.

OBJECTIVE: Toll-like receptors (TLRs) are integral parts of the innate immune system and have been implicated in complications of pregnancy. The longitudinal expression of TLRs on dendritic cells in the maternal circulation during uncomplicated pregnancies is unknown. The objective of this study was to prospectively evaluate TLRs 1-9 as expressed on dendritic cells in the maternal circulation at defined intervals throughout pregnancy and postpartum. STUDY DESIGN: This was a prospective cohort of 30 pregnant women with uncomplicated pregnancies and 30 nonpregnant controls. TLRs and cytokine expression was measured in unstimulated dendritic cells at 4 defined intervals during pregnancy and postpartum. Basal expression of TLRs and cytokines was measured by multicolor flow cytometry. The percent-positive dendritic cells for each TLRs were compared with both nonpregnant and postpartum levels with multivariate linear regression. RESULTS: TLRs 1, 7, and 9 were elevated compared with nonpregnant controls with persistent elevation of TLR 1 and interleukin-12 (IL-12) into the postpartum period. Concordantly, levels of IL-6, IL-12, interferon alpha, and tumor necrosis factor alpha increased during pregnancy and returned to levels similar to nonpregnant controls during the postpartum period. The elevated levels of TLR 1 and IL-12 were persistent postpartum, challenging notions that immunologic changes during pregnancy resolve after the prototypical postpartum period. CONCLUSION: Normal pregnancy is associated with time-dependent changes in TLR expression compared with nonpregnant controls; these findings may help elucidate immunologic dysfunction in complicated pregnancies.

Circulating Angiogenic Factor Levels in Hypertensive Disorders of Pregnancy.

BACKGROUND: Among women with hypertensive disorders of pregnancy, biomarkers may stratify risk for developing preeclampsia with severe features (sPE). METHODS: Across 18 U.S. centers, we prospectively measured the ratio of serum soluble fms-like tyrosine kinase 1 (sFlt-1) to placental growth factor (PlGF) in pregnant women hospitalized between 23 and 35 weeks of gestation. The primary outcome was predicting sPE, and secondary outcomes included predicting adverse outcomes within 2 weeks. The prognostic performance of the sFlt-1:PlGF ratio was assessed by using a derivation/validation design. RESULTS: A total of 1014 pregnant women were evaluated; 299 were included in the derivation cohort and 715 in the validation cohort. In the derivation cohort, the median sFlt-1:PlGF ratio was 200 (interquartile range, 53 to 458) among women who developed sPE compared with 6 (interquartile range, 3 to 26) in those who did not (P<0.001). The discriminatory ratio of ≥40 was then tested in the validation cohort and yielded a 65% positive (95% confidence interval [CI], 59 to 71) and a 96% negative (95% CI, 93 to 98) predictive value for the primary outcome. The ratio performed better than standard clinical measures (area under the receiver-operating characteristic curve, 0.92 versus <0.75 for standard-of-care tests). Compared with women with a ratio <40, women with a ratio ≥40 were at higher risk for adverse maternal outcomes (16.1% versus 2.8%; relative risk, 5.8; 95% CI, 2.8 to 12.2). CONCLUSIONS: In women with a hypertensive disorder of pregnancy presenting between 23 and 35 weeks of gestation, measurement of serum sFlt-1:PlGF provided stratification of the risk of progressing to sPE within the coming fortnight. (Funded by Cedars-Sinai Medical Center and Thermo Fisher Scientific; ClinicalTrials.gov NCT03815110.)

Uptake of influenza vaccine in pregnant women during the 2009 H1N1 influenza pandemic.

The goals of this study were to define the uptake of H1N1 and seasonal influenza vaccination during pregnancy among women delivering during the 2009 H1N1 pandemic and explore barriers to vaccination. All postpartum women at the Massachusetts General Hospital from January 2010 through March 2010 were invited to complete an anonymous questionnaire about demographics, vaccination status, and attitudes about vaccination during pregnancy. Among 370 participants (53% response rate), 81% accepted both the H1N1 and seasonal influenza vaccines during pregnancy. Patients who declined one or both vaccines cited concerns over safety as a major deterrent. Of the 36% of participants who reported having flu-like symptoms during this pregnancy only 8.6% took oseltamivir. While a high vaccination rate was identified in this study, further education is needed to reassure patients regarding vaccine safety. Education for providers and patients emphasizing the benefits of early treatment of pregnant women with flu-like symptoms should be a priority.

Prenatal diagnosis of ectopic intrathoracic kidney in a fetus with a left diaphragmatic hernia.

Intrathoracic renal ectopia as a result of a congenital diaphragmatic hernia (CDH) is a rare congenital anomaly. We present a case in which the prenatal diagnosis of an ectopic intrathoracic kidney was made on routine anatomical survey at 28 weeks' gestation. Color doppler sonography imaging revealed the renal artery coursing into the infant's thorax and was consistent with CDH, but fetal MRI suggested an intact diaphragm. However, neonatal evaluation confirmed the diagnosis of intrathoracic kidney with posterior CDH, which was repaired without complication. In contrast to diaphragmatic hernia with liver or bowel herniation, infants with intrathoracic ectopic kidneys generally do well.

Prenatal diagnosis of an umbilical vein aneurysm: a case report.

Aneurysm of the umbilical vessels is a rare abnormality and has seldom been diagnosed prenatally. We report a case in which dilatation of the intra-amniotic umbilical cord was seen on prenatal ultrasound at 34-weeks gestation. This was believed to represent an umbilical vein aneurysm and was confirmed on subsequent pathological examination after delivery. A review of the literature concerning these uncommon vascular abnormalities of the umbilical cord is presented.

Dendritic cells in the circulation of women with preeclampsia demonstrate a pro-inflammatory bias secondary to dysregulation of TLR receptors.

Toll-like receptors (TLRs) are central components of the innate immune system that recognize both microbial ligands and host products released during tissue damage. Data from epidemiologic studies and animal models suggest that inappropriate activation of the immune system plays a critical role in the development of preeclampsia. This study evaluates in a systematic fashion the expression and function of TLRs in the circulation of patients with preeclampsia compared to healthy pregnant controls. We evaluated TLR expression and function in primary dendritic cells (DCs) of 30 patients with preeclampsia and 30 gestational age-matched healthy pregnant controls. DCs were stimulated with the different TLR ligands engaging TLR1/2, TLR2/6, TLR3, TLR4, TLR5, TLR7, TLR8 and TLR9. The expression of TLR-induced production of TNF-α, IFN-α, IL-6, and IL-12 were measured by multicolor flow cytometry. Basal expression of TLR3, TLR4 and TLR9 was significantly increased in DCs isolated from women with preeclampsia. Preeclamptic DCs also expressed significantly higher basal levels of cytokines. In contrast, preeclamptic DCs demonstrated a less robust response to stimulation with various TLR ligands as compared with healthy pregnant controls. Under basal conditions, DCs from preeclamptic individuals express higher levels of select TLRs and produce more pro-inflammatory cytokines as compared with healthy controls. As such, the ability of these cells to mount an inflammatory reaction in response to a TLR ligand is limited. These data demonstrate a dysregulated pattern of TLR expression and cytokine production in DCs from PE patients that may limit further activation by TLR engagement.

First-trimester cystic hygroma: relationship of nuchal translucency thickness and outcomes.

OBJECTIVE: To estimate the relationship between nuchal translucency thickness and abnormal karyotype, major congenital anomaly, perinatal loss, and composite abnormal outcome in fetuses with first-trimester nuchal cystic hygroma. METHODS: We performed a retrospective cohort study of first-trimester fetuses with ultrasound-diagnosed nuchal cystic hygroma collected over a 10-year period. RESULTS: There were 944 first-trimester fetuses with nuchal cystic hygroma. A karyotype abnormality occurred in 54.9% (400 of 729) of fetuses. A major congenital anomaly occurred in 28.8% (61 of 212) of fetuses with a normal karyotype. Perinatal loss occurred in 39% (115 of 295) of fetuses not electively terminated. Overall, an abnormal outcome occurred in 86.6% (543 of 627) of fetuses. After adjusting for potential confounders, every 1-mm increase in nuchal translucency thickness increased the odds of an abnormal karyotype by 44% (adjusted odds ratio [OR] 1.44, 95% confidence interval [CI] 1.29-1.60, P<.001), the odds of major congenital anomaly by 26% (adjusted OR 1.26, 95% CI, 1.08-1.47, P=.003), the odds of perinatal loss by 47% (adjusted OR 1.47, 95% CI 1.07-2.02, P=.019), and the odds of a composite abnormal outcome by 77% (adjusted OR 1.77, 95% CI 1.15-2.74, P=.01). CONCLUSION: First-trimester nuchal cystic hygroma is associated with high rates of karyotype abnormality, major congenital anomaly, perinatal loss, and abnormal outcome. As the thickness of the nuchal translucency increases, the odds of abnormal karyotype, major congenital anomaly, perinatal loss, and abnormal outcome increase.

Influenza vaccination during pregnancy and factors for lacking compliance with current CDC guidelines.

BACKGROUND: The Center for Disease Control and Prevention (CDC) and the American College of Obstetricians and Gynecologists (ACOG) recommend influenza vaccination for all pregnant women during the influenza season. However, the actual rate of vaccination is substantially below the target levels. Given the recent emergence of novel influenza strains, there is an important need to address knowledge gaps in women and their healthcare providers to improve vaccination coverage for pregnant women during inter-pandemic and pandemic periods. This study attempted to identify potentially remediable attitudinal factors among women and their physicians that may present barriers to influenza vaccination and then assess the impact of interventions to increase the influenza vaccination rate in pregnant women. METHODS: This prospective study initially analyzed patient and physician knowledge regarding the influenza vaccine in pregnancy and then examined the impact of several interventions aimed to increase immunization rates implemented over the following year. Influenza vaccination rates were assessed before and after the interventions. RESULTS: Five hundred twenty patients were enrolled in the study during the influenza season 2007/2008. Only 19% of those patients reported receiving the influenza vaccination and only 28% recalled that the vaccine was offered. Following this, in the summer and fall of 2008, we performed a physician education program and distributed posters advertising the influenza vaccine to all offices offering prenatal care in our area in order to increase patient awareness of the need for the vaccine. In the following influenza season, we again reassessed the vaccination rate and patient's knowledge and awareness of the vaccine in 480 postpartum women. Influenza vaccination rates increased from 19% to 31%. After the intervention, 51% of patients recalled that the vaccine was offered to them during the pregnancy as opposed to only 28% the year prior. CONCLUSION: Understanding the specific barriers to vaccination that our population faced was helpful in designing the interventions to improve knowledge and acceptance of influenza vaccination in pregnancy, which led to an increased vaccination rates in women.

Selected viral infections in pregnancy.

This article reviews the impact of seasonal influenza on pregnancy with particular emphasis on the 2009 novel H1N1 pandemic. Antiviral therapy for influenza, as well as recommendations and safety data on vaccination are discussed. In addition, the impact of hepatitis A, B, and C in pregnancy is addressed with a focus on prevention and treatment strategies for hepatitis B and C.

Antibiotic resistance and penicillin tolerance in ano-vaginal group B streptococci.

OBJECTIVES: We sought to determine the prevalence of group B streptococcus (GBS) colonisation and to characterise antibiotic resistance patterns. METHODS: Vaginal and ano-rectal cultures were evaluated for GBS colonisation, and antibiotic susceptibility profiles were determined to 15 antibiotics according to the guidelines of the National Committee for Clinical Laboratory Standards. RESULTS: Our GBS prevalence was 30%. All isolates were sensitive to amoxicillin/clavulanic acid, ampicillin, ampicillin/sulbactam, cefotaxime, ceftriaxone, cefuroxime-sodium, imipenem, linezolid, penicillin G and vancomycin. Thirty-two percent of the isolates were resistant to azithromycin, 21% to clindamycin, 25% to erythromycin and 23% to tetracycline. CONCLUSIONS: The relatively high rates of resistance to four of the 15 antibiotics tested confirm that for women allergic to penicillin and colonised with GBS, antibiotic sensitivities should be determined. We noticed increasing resistance to clindamycin over a 7-year period. Ongoing surveillance of local antibiotic resistance patterns at the institutional level is important in determining optimal prophylaxis as resistance patterns differ between institutions and are increasing.

Regulation of Nod1 and Nod2 in first trimester trophoblast cells.

PROBLEM: The cytoplasmic pattern recognition receptors, Nod1 and Nod2, are thought to be important for detecting intracellular bacteria. We have previously reported that first trimester trophoblast cells express Nod1 and Nod2, and that trophoblast Nod2 activation triggers an inflammatory response. The objectives of this study were to characterize the effects of Nod1 stimulation, and to determine the regulation of Nod1 and Nod2, in the trophoblast. METHOD OF STUDY: The effect of Nod1 activation on trophoblast cells was determined by analyzing the cytokine response following treatment with gamma-D-glutamyl-meso-diaminopimelic acid (iE-DAP). The regulation of Nod1 and Nod2 expression by trophoblast cells was evaluated by RT-PCR. RESULTS: Treatment of trophoblast cells with iE-DAP significantly increased their production of cytokines and chemokines. In addition, Nod1 and Nod2 mRNA expression was upregulated following treatment of trophoblast cells with lipopolysaccharide (LPS), and this was significantly reduced by the presence of a NFkappaB inhibitor and a TLR4-dominant negative (DN). CONCLUSION: This study demonstrates that LPS, through TLR4, increases trophoblast expression of Nod1 and Nod2 via the NFkappaB pathway; and that Nod1 is functional in the trophoblast. These findings suggest that extracellular recognition of bacterial LPS by TLR4 may prime the trophoblast in preparation for its cytoplasmic recognition of, and response to, bacterial peptides through the Nod proteins.

Antiphospholipid antibodies induce a pro-inflammatory response in first trimester trophoblast via the TLR4/MyD88 pathway.

PROBLEM: Women with antiphospholipid antibodies (aPL) are at risk for recurrent miscarriage, pre-eclampsia, and pre-term labor. aPL target the placenta directly by binding to beta(2)-glycoprotein I (beta(2)GPI) expressed on the surface of trophoblast cells. The objective of this study was to determine the effects of aPL on trophoblast function and the mechanisms involved. METHOD OF STUDY: First trimester trophoblast cells were treated with anti-beta(2)GPI monoclonal antibodies and patient-derived aPL, after which cell survival and function was evaluated. RESULTS: We report that anti-beta(2)GPI antibodies trigger an inflammatory response in trophoblast, characterized by increased secretion of interleukin (IL)-8, MCP-1, GRO-alpha, and IL-1beta, and that this occurs in a TLR-4/MyD88-dependent manner. At high concentrations, these antibodies also induce caspase-mediated cell death. This was attenuated upon disabling of the MyD88 pathway, suggesting that anti-beta(2)GPI-induced inflammatory mediators compromise trophoblast survival by acting in an autocrine/paracrine manner. Enhanced IL-8, GRO-alpha, and IL-1beta secretion also occurred when trophoblast cells were incubated with antibodies from patients with antiphospholipid syndrome. Heparin, which acts as a pro-survival factor in human trophoblast, attenuated the anti-beta(2)GPI antibody-mediated cell death, and also the pro-inflammatory response, but only at high concentrations. CONCLUSION: These findings demonstrate that aPL triggers a placental inflammatory response via the TLR-4/MyD88 pathway, which in turn compromises trophoblast survival. Thus, the TLR-4/MyD88 pathway may provide a new therapeutic target to improve pregnancy outcome in antiphospholipid syndrome patients.