Molecular microbiological methods in the diagnosis of neonatal sepsis

Efficacy of short-course antibiotics for culture-positive neonatal sepsis: A systematic review and meta-analysis

Sepsis is a common cause of neonatal mortality and morbidity. Though antibiotics are the mainstay of treatment in culture-positive neonatal sepsis, the dilemma persists for the optimum duration of antimicrobial therapy. The present study aimed to evaluate the efficacy of short-course antibiotics for uncomplicated culture-positive neonatal sepsis. This systematic review and meta-analysis (PROSPERO: CRD42023444899) identified, appraised, and synthesised the available evidence from randomised and quasi-randomised controlled trials related to the efficacy of short-course (7-10 days) versus standard-course (14 days) antibiotics for uncomplicated culture-positive neonatal sepsis on the rate of treatment failure, mortality, duration of hospitalisation, morbidities including antibiotics-related adverse events, long-term neurodevelopmental outcomes and cost analysis. Data were pooled using RevMan 5.4 software. Certainty of evidence (COE) for predefined outcomes was analysed by GRADE. Available evidence showed no significant difference in the rate of treatment failure between 7- to 10-day versus 14-day antibiotics courses [risk ratio (95% confidence interval, CI), 2.45 (0.93-6.47), I2 = 0%, six studies, n = 573, very low COE]. No incidence of death was reported in either treatment arm in the two included studies. Duration of hospitalisation was significantly shorter with the short-course antibiotics arm compared to standard-course [mean difference (95% CI), -3.88 (-4.22 to -3.54) days, I2 = 0%, five studies, n = 507, low COE]. Morbidities reported in the three studies were similar. Other outcomes were not reported. To conclude the evidence is very uncertain about the effect of short-course antibiotic regimen, compared to a standard-course, on the treatment failure rate in uncomplicated culture-positive neonatal sepsis. Adequately powered trials with outcomes including death and long-term neurodevelopmental impairment are needed.

Factors Associated with Post-rewarming Procalcitonin Levels in Newborns with Hypoxic Ischemic Encephalopathy

To determine the factors associated with the procalcitonin levels in newborns with hypoxic-ischemic encephalopathy (HIE) who received therapeutic hypothermia (TH). The neonates, who had moderate/severe HIE and were treated with TH, were included. The neonates were arranged into 2 groups by procalcitonin (PCT) level after rewarming was completed. The neonates who had a procalcitonin level of < 2.5 ng/ml constituted Group 1 and the ones who had a procalcitonin level of ≥ 2.5 ng/ml constituted Group 2. Univariate and multivariate logistic regression was used to assess the factors related with PCT level. The first group included 123 (87.9%) neonates and the second group included 17 (12.1%) neonates. The median gestational age was 38 (36-39) weeks and the mean birth weight was 3081.7 ± 552.8 grams. In group 2, the rates for severe HIE, cesarean section, antibiotic switch, convulsion, inotrope use and mortality were higher, and duration of hospitalization was longer, whereas Apgar scores were lower (P < .05). The risk of a high procalcitonin level was found to be 6-fold (95% CI 1.9-19.1) higher in severe HIE and 5.2-fold higher (95% CI 1.7-16) in cesarean delivery. In neonates with HIE/TH, high post-rewarming procalcitonin levels were related with severe HIE and cesarean delivery. Some other clinical and laboratory findings, which may reflect worse clinical status, were also associated with high procalcitonin levels.

Universal Digital High-Resolution Melt Analysis for the Diagnosis of Bacteremia

Fast and accurate diagnosis of bloodstream infection is necessary to inform treatment decisions for septic patients, who face hourly increases in mortality risk. Blood culture remains the gold standard test but typically requires approximately 15 hours to detect the presence of a pathogen. We, therefore, assessed the potential for universal digital high-resolution melt (U-dHRM) analysis to accomplish faster broad-based bacterial detection, load quantification, and species-level identification directly from whole blood. Analytical validation studies demonstrated strong agreement between U-dHRM load measurement and quantitative blood culture, indicating that U-dHRM detection is highly specific to intact organisms. In a pilot clinical study of 17 whole blood samples from pediatric patients undergoing simultaneous blood culture testing, U-dHRM achieved 100% concordance when compared with blood culture and 88% concordance when compared with clinical adjudication. Moreover, U-dHRM identified the causative pathogen to the species level in all cases where the organism was represented in the melt curve database. These results were achieved with a 1-mL sample input and sample-to-answer time of 6 hours. Overall, this pilot study suggests that U-dHRM may be a promising method to address the challenges of quickly and accurately diagnosing a bloodstream infection.

Application of Advanced Molecular Methods to Study Early-Onset Neonatal Sepsis

Early-onset sepsis (EOS) is a global health issue, considered one of the primary causes of neonatal mortality. Diagnosis of EOS is challenging because its clinical signs are nonspecific, and blood culture, which is the current gold-standard diagnostic tool, has low sensitivity. Commonly used biomarkers for sepsis diagnosis, including C-reactive protein, procalcitonin, and interleukin-6, lack specificity for infection. Due to the disadvantages of blood culture and other common biomarkers, ongoing efforts are directed towards identifying innovative molecular approaches to diagnose neonates at risk of sepsis. This review aims to gather knowledge and recent research on these emerging molecular methods. PCR-based techniques and unrestricted techniques based on 16S rRNA sequencing and 16S-23S rRNA gene interspace region sequencing offer several advantages. Despite their potential, these approaches are not able to replace blood cultures due to several limitations; however, they may prove valuable as complementary tests in neonatal sepsis diagnosis. Several microRNAs have been evaluated and have been proposed as diagnostic biomarkers in EOS. T2 magnetic resonance and bioinformatic analysis have proposed potential biomarkers of neonatal sepsis, though further studies are essential to validate these findings.

Diagnostic Accuracy of Multiplex Polymerase Chain Reaction in Early Onset Neonatal Sepsis

Early onset neonatal sepsis is a significant contributor to neonatal morbidity and mortality. Although blood cultures remain the diagnostic gold standard, they detect pathogens in only a minority of suspected cases. This study compared the accuracy of blood cultures with a rapid multiplex PCR test. Newborns at risk of neonatal sepsis were prospectively screened as recommended per national guidelines. Evaluations included laboratory parameters (CrP, IL6, differential blood count), blood culture, and a molecular multiplex PCR test (ROCHE LightCycler SeptiFast®) identifying 20 common microbial agents. Blood samples were taken simultaneously from umbilical cord or venous sources on the first day of life. Of 229 infants included, 69% were born preterm. Blood culture and multiplex PCR sensitivity were 7.4% and 14.8%, respectively. Specificity, negative and positive predictive values between methods showed no significant variance, although multiplex PCR had more false positives due to contamination. The limited sensitivity of blood cultures for early onset neonatal sepsis is concerning. Despite quicker results, multiplex PCR does not enhance diagnostic accuracy or antibiotic therapy guidance, thus it cannot be recommended for this indication.

Universal digital high resolution melt analysis for the diagnosis of bacteremia

Fast and accurate diagnosis of bloodstream infection is necessary to inform treatment decisions for septic patients, who face hourly increases in mortality risk. Blood culture remains the gold standard test but typically requires ∼15 hours to detect the presence of a pathogen. Here, we assess the potential for universal digital high-resolution melt (U-dHRM) analysis to accomplish faster broad-based bacterial detection, load quantification, and species-level identification directly from whole blood. Analytical validation studies demonstrated strong agreement between U-dHRM load measurement and quantitative blood culture, indicating that U-dHRM detection is highly specific to intact organisms. In a pilot clinical study of 21 whole blood samples from pediatric patients undergoing simultaneous blood culture testing, U-dHRM achieved 100% concordance when compared with blood culture and 90.5% concordance when compared with clinical adjudication. Moreover, U-dHRM identified the causative pathogen to the species level in all cases where the organism was represented in the melt curve database. These results were achieved with a 1 mL sample input and sample-to-answer time of 6 hrs. Overall, this pilot study suggests that U-dHRM may be a promising method to address the challenges of quickly and accurately diagnosing a bloodstream infection.

Universal digital high resolution melt analysis for the diagnosis of bacteremia

April Aralar, Tyler Goshia, Nanda Ramchandar, Shelley M. Lawrence, Aparajita Karmakar, Ankit Sharma, Mridu Sinha, David Pride, Peiting Kuo, Khrissa Lecrone, Megan Chiu, Karen Mestan, Eniko Sajti, Michelle Vanderpool, Sarah Lazar, Melanie Crabtree, Yordanos Tesfai, Stephanie I. Fraley.

Metagenomics by next-generation sequencing (mNGS) in the etiological characterization of neonatal and pediatric sepsis: A systematic review

Introduction

Pediatric and neonatal sepsis is one of the main causes of mortality and morbidity in these age groups. Accurate and early etiological identification is essential for guiding antibiotic treatment, improving survival, and reducing complications and sequelae. Currently, the identification is based on culture-dependent methods, which has many limitations for its use in clinical practice, and obtaining its results is delayed. Next-generation sequencing enables rapid, accurate, and unbiased identification of multiple microorganisms in biological samples at the same time. The objective of this study was to characterize the etiology of neonatal and pediatric sepsis by metagenomic techniques.

Methods

A systematic review of the literature was carried out using the PRISMA-2020 guide. Observational, descriptive, and case report studies on pediatric patients were included, with a diagnostic evaluation by clinical criteria of sepsis based on the systemic inflammatory response, in sterile and non-sterile biofluid samples. The risk of bias assessment of the observational studies was carried out with the STROBE-metagenomics instrument and the CARE checklist for case reports.

Results and Discussion

Five studies with a total of 462 patients were included. Due to the data obtained from the studies, it was not possible to perform a quantitative synthesis (meta-analysis). Based on the data from the included studies, the result identified that mNGS improves the etiological identification in neonatal and pediatric sepsis, especially in the context of negative cultures and in the identification of unusual microorganisms (bacteria that are difficult to grow in culture, viruses, fungi, and parasites). The number of investigations is currently limited, and the studies are at high risk of bias. Further research using this technology would have the potential to improve the rational use of antibiotics.

Chorioamnionitis-exposure alters serum cytokine trends in premature neonates

OBJECTIVES

Determine if chronologic age and/or chorioamnionitis exposure alter normal serum cytokine and chemokine levels in uninfected preterm neonates during their initial NICU stay.

STUDY DESIGN

A 7-plex immunoassay measured levels of serum IL-1β, IL-6, IL-8, IL-10, TNF-α, CCL2, and CCL3 longitudinally from chorioamnionitis-exposed and unexposed preterm neonates under 33 weeks' gestation.

RESULTS

Chorioamnionitis-exposed and unexposed preterm neonates demonstrated differences in the trends of IL-1β, IL-6, IL-8, IL-10, TNF-α, and CCL2 over the first month of life. The unexposed neonates demonstrated elevated levels of these inflammatory markers in the first two weeks of life with a decrease by the third week of life, while the chorioamnionitis-exposed neonates demonstrated differences over time without a predictable pattern. Chorioamnionitis-exposed and unexposed neonates demonstrated altered IL-10 and TNF-α trajectories over the first twelve weeks of life.

CONCLUSION

Chorioamnionitis induces a state of immune dysregulation in preterm neonates that persists beyond the immediate neonatal period.

Predictive Scores for Late-Onset Neonatal Sepsis as an Early Diagnostic and Antimicrobial Stewardship Tool: What Have We Done So Far?

Background: Late-onset neonatal sepsis (LOS) represents a significant cause of morbidity and mortality worldwide, and early diagnosis remains a challenge. Various ‘sepsis scores’ have been developed to improve early identification. The aim of the current review is to summarize the current knowledge on the utility of predictive scores in LOS as a tool for early sepsis recognition, as well as an antimicrobial stewardship tool. Methods: The following research question was developed: Can we diagnose LOS with accuracy in neonates using a predictive score? A systematic search was performed in the PubMed database from 1982 (first predictive score published) to December 2021. Results: Some (1352) articles were identified—out of which, 16 were included in the review. Eight were original scores, five were validations of already existing scores and two were mixed. Predictive models were developed by combining a variety of clinical, laboratory and other variables. The majority were found to assist in early diagnosis, but almost all had a limited diagnostic accuracy. Conclusions: There is an increasing need worldwide for a simple and accurate score to promptly predict LOS. Combinations of the selected parameters may be helpful, but until now, a single score has not been proven to be comprehensive.

Re-visiting micro ESR as a screening tool for neonatal sepsis

Our study evaluated the role of micro-erythrocte sedimentation rate (micro-ESR) in the early detection of neonatal sepsis.

Neonates with >34 completed weeks of gestation, appropriate for gestational age, admitted in our Neonatal Intensive Care Unit with clinical suspicion of early onset sepsis were enrolled in the study. A sepsis screen and blood culture was performed on all the babies within 4 h of admission. The sensitivity of micro-ESR for detecting positive blood culture was calculated and the best cut-off was determined using the Area Under Curve.

Cell-free hemoglobin is a marker of systemic inflammation in mouse models of sepsis: a Raman spectroscopic study

Sepsis is a life-threatening condition caused by heightened host immune responses post infection. Despite intensive research, most of the existing diagnostic methods remain non-specific, labour-intensive, time-consuming or are not sensitive enough for rapid and timely diagnosis of the onset and progression of sepsis. The present work was undertaken to explore the potential of Raman spectroscopy to identify the biomarkers of sepsis in a label-free and minimally invasive manner using different mouse models of inflammation. The sera of BALB/c mice infected with Salmonella Typhimurium reveal extensive hemolysis, as indicated by the Raman bands that are characteristic of the porphyrin ring of hemoglobin (668, 743, 1050, 1253 and 1397 cm-1) which increase in a kinetic manner. These markers are also observed in a lipopolysaccharide-induced endotoxic shock model, but not in a thioglycollate-induced sterile peritonitis model. These data demonstrate that hemolysis is a signature of systemic, but not localised, inflammation. To further validate our observations, sepsis was induced in the nitric oxide synthase 2 (Nos2-/-) deficient strain which is more sensitive to infection. Interestingly, Nos2-/- mice exhibit a higher degree of hemolysis than C57BL/6 mice. Sepsis-induced hemolysis was also confirmed using resonance Raman spectroscopy with 442 nm excitation which demonstrated a pronounced increase in the resonant Raman bands at 670 and 1350 cm-1 in sera of the infected mice. This is the first study to identify inflammation-induced hemolysis in mouse models of sepsis using Raman spectral signatures for hemoglobin. The possible implications of this method in detecting hemolysis in different inflammatory pathologies, such as the ongoing COVID-19 pandemic, are discussed.

Development of Prediction Models for New Integrated Models and a Bioscore System to Identify Bacterial Infections in Systemic Lupus Erythematosus

Objectives

Distinguishing flares from bacterial infections in systemic lupus erythematosus (SLE) patients remains a challenge. This study aimed to build a model, using multiple blood cells and plasma indicators, to improve the identification of bacterial infections in SLE.

Design

Building PLS-DA/OPLS-DA models and a bioscore system to distinguish bacterial infections from lupus flares in SLE.

Setting

Department of Rheumatology of the Second Hospital of Shanxi Medical University.

Participants

SLE patients with flares (n = 142) or bacterial infections (n = 106) were recruited in this retrospective study.

Outcome

The peripheral blood of these patients was collected by the experimenter to measure the levels of routine examination indicators, immune cells, and cytokines. PLS-DA/OPLS-DA models and a bioscore system were established.

Results

Both PLS-DA (R2Y = 0.953, Q2 = 0.931) and OPLS-DA (R2Y = 0.953, Q2 = 0.942) models could clearly identify bacterial infections in SLE. The white blood cell (WBC), neutrophile granulocyte (NEUT), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), procalcitonin (PCT), interleukin-6 (IL-6), IL-10, interferon-γ (IFN-γ), and tumor necrosis factor α (TNF-α) levels were significantly higher in bacteria-infected patients, while regulatory T (Treg) cells obviously decreased. A multivariate analysis using the above 10 dichotomized indicators, based on the cut-off value of their respective ROC curve, was established to screen out the independent predictors and calculate their weights to build a bioscore system, which exhibited a strong diagnosis ability (AUC = 0.842, 95% CI 0.794–0.891). The bioscore system showed that 0 and 100% of SLE patients with scores of 0 and 8–10, respectively, were infected with bacteria. The higher the score, the greater the likelihood of bacterial infections in SLE.

Conclusions

The PLS-DA/OPLS-DA models, including the above biomarkers, showed a strong predictive ability for bacterial infections in SLE. Combining WBC, NEUT, CRP, PCT, IL-6, and IFN-γ in a bioscore system may result in faster prediction of bacterial infections in SLE and may guide toward a more appropriate, timely treatment for SLE.

Visual multiple cross displacement amplification for the rapid identification of S. agalactiae immediately from vaginal and rectal swabs

Streptococcus agalactiae (S. agalactiae) is an important pathogen that can lead to neonatus and mother infection. The current existing techniques for the identification of S. agalactiae are limited by accuracy, speed and high-cost. Therefore, a new multiple cross displacement amplification (MCDA) assay was developed for test of the target pathogen immediately from vaginal and rectal swabs. MCDA primers screening were conducted targeting S. agalactiae pcsB gene, and one set of MCDA primers with better rapidity and efficiency was selected for establishing the S. agalactiae-MCDA assay. As a result, the MCDA method could be completed at a constant temperature of 61 °C, without the requirement of special equipment. The detection limit is 250 fg (31.5 copies) per reaction, all S. agalactiae strains displayed positive results, but not for non-S. agalactiae strains. The visual MCDA assay detected 16 positive samples from 200 clinical specimen, which were also detected positive by enrichment/qPCR. While the CHROMagar culture detected 6 positive samples. Thus, the MCDA assay is prefer to enrichment/qPCR and culture for detecting S. agalactiae from clinical specimen. Particularly, the whole test of MCDA takes about 63.1 min, including sample collection (3 min), DNA preparation (15 min), MCDA reaction (45 min) and result reporting (6 s). In addition, the cost was very economic, with only US$ 4.9. These results indicated that our S. agalaciae-MCDA assay is a rapid, sensitive and cost-efficient technique for target pathogen detection, and is more suitable than conventional assays for an urgent detection, especially for 'on-site' laboratories and resource-constrained settings.

Association of Routinely Measured Proinflammatory Biomarkers With Abnormal MRI Findings in Asphyxiated Neonates Undergoing Therapeutic Hypothermia

Background: The neuroprotective treatment effect of therapeutic hypothermia (TH) following perinatal asphyxia may be negatively influenced by neonatal sepsis and concomitant inflammation. We aimed to correlate routinely used blood biomarkers for perinatal sepsis in cooled asphyxiated newborns with MRI findings. Methods: Perinatal data was retrospectively collected from 67 cooled asphyxiated newborns. Levels of C-reactive protein (CRP), white blood cells and platelets were analyzed before, during and after TH. Interleukin-6 blood levels were analyzed before initiation of TH. Magnetic resonance imaging (MRI) on postnatal day 5-7 was used defining short-term outcome. Adverse outcome was defined as death or adverse MRI findings. Amplitude-integrated electroencephalography (aEEG) was additionally analyzed and correlated with short-term MRI outcome. Results: Forty-nine newborns had favorable short-term MRI outcome. Perinatal data referring to perinatal sepsis did not differ significantly between groups. IL-6 levels before initiation of TH and CRP levels on day three and after TH were significantly higher in newborns with adverse short-term MRI outcome. Males with adverse short-term MRI outcome had significantly increased CRP values at the end of the cooling phase. aEEG strongly correlated with short-term MRI outcome. Conclusion: Routinely used blood biomarkers may be helpful early identifying newborns at high risk of unfavorable outcome and in need of close neurodevelopmental follow-up.

Toward Early Diagnosis of Late-Onset Sepsis in Preterm Neonates: Dual Magnetoimmunosensor for Simultaneous Procalcitonin and C-Reactive Protein Determination in Diagnosed Clinical Samples

Early diagnosis of sepsis, combining blood cultures and inflammation biomarkers, continues to be a challenge, especially in very low birth weight (VLBW) infants because of limited availability of blood samples. Traditional diagnostic procedures are cumbersome, not fast enough, and require relatively large volumes of sample. Empiric use of antibiotics, before diagnostic confirmation, is required to decrease mortality, leading to potential antibiotic resistance and side effects in VLBW infants. To solve such a serious problem, a dual magnetoimmunosensor is proposed for simultaneous assessment of two of the most important sepsis biomarkers: procalcitonin (PCT for early phase) and C-reactive protein (CRP for late phase). This "sample-to-result" approach exhibited excellent sensitivity, selectivity, precision, and stability using low sample volumes (<30 μL) and under 20 min of total assay. The analytical usefulness of the approach was demonstrated by analyzing clinically relevant samples of preterm neonates with suspicion of sepsis.

Interfacial Effect-Based Quantification of Droplet Isothermal Nucleic Acid Amplification for Bacterial Infection

Bacterial infection is a widespread problem in humans that can potentially lead to hospitalization and morbidity. The largest obstacle for physicians/clinicians is the time delay in accurately identifying infectious bacteria, especially their sub-species, in order to adequately treat and diagnose such infected patients. Loop-mediated amplification (LAMP) is a nucleic acid amplification method that has been widely used in diagnostic applications due to its simplicity of constant temperature, use of up to 4 to 6 primers (rendering it highly specific), and capability of amplifying low copies of target sequences. Use of interfacial effect-based monitoring is expected to dramatically shorten the time-to-results of nucleic acid amplification techniques. In this work, we developed a LAMP-based point-of-care platform for detection of bacterial infection, utilizing smartphone measurement of contact angle from oil-immersed droplet LAMP reactions. Whole bacteria (Escherichia coli O157:H7) were assayed in buffer as well as 5% diluted human whole blood. Monitoring of droplet LAMP reactions was demonstrated in a three-compartment, isothermal proportional-integrated-derived (PID)-controlled chip. Smartphone-captured images of droplet LAMP reactions, and their contact angles, were evaluated. Contact angle decreased substantially upon target amplification in both buffer and whole blood samples. In comparison, no-target control (NTC) droplets remained stable throughout the 30 min isothermal reactions. These results were explained by the pre-adsorption of plasma proteins to an oil-water interface (lowering contact angle), followed by time-dependent amplicon formation and their preferential adsorption to the plasma protein-occupied oil-water interface. Time-to-results was as fast as 5 min, allowing physicians to quickly make their decision for infected patients. The developed assay demonstrated quantification of bacteria concentration, with a limit-of-detection at 102 CFU/μL for buffer samples, and binary target or no-target identification with a limit-of-detection at 10 CFU/μL for 5% diluted whole blood samples.

Peripheral neutrophil CD64 index combined with complement, CRP, WBC count and B cells improves the ability of diagnosing bacterial infection in SLE

OBJECTIVE

To investigate the diagnostic role of complement C3, complement C4, C-reactive protein (CRP), procalcitonin (PCT), white blood cell count (WBC), neutrophil CD64 (nCD64) index, lymphocyte subsets and their combination in differentiating bacterial infection from disease relapse in systemic lupus erythematosus (SLE).

METHODS

The above biomarkers in 36 hospitalized SLE patients with bacterial infection and 45 with lupus flare without infection were retrospectively studied. Bacterial infection was proven by positive cultures or typical clinical symptoms and signs combined with positive response to antibiotics. Lupus flare was defined as three points greater than their previous SLE disease activity index score. The diagnostic value for bacterial infection was evaluated by the areas under the receiver operating characteristic curves (AUC) and a novel bioscore system combining multiple biomarkers.

RESULTS

Increased CRP ( p = 0.049), WBC ( p = 0.028) and nCD64 index ( p = 0.034) were observed in the infected group and C3 ( p = 0.001), C4 ( p = 0.016) and B cells levels ( p = 0.010) were significantly reduced. The AUC for the above six biomarkers had no significant difference. Interestingly, the combination of nCD64 index, CRP, WBC, C3 and C4 improved significantly the diagnostic potential of SLE infection (AUC 0.783 (interquartile range 0.672, 0.871), p < 0.001; sensitivity 85.29% specificity 62.50%). In the bioscore system including the above six biomarkers, the bacterial infection rate in patients with bioscore ≤2, 3, 4, 5 and 6 were 0.00, 39.29, 59.10, 61.54 and 100.00%, respectively.

CONCLUSION

The combination of nCD64 index, C3, C4, CRP, WBC and B cells in a bioscore is useful to diagnose bacterial infection in SLE.

Evaluation of updated sepsis scoring systems and systemic inflammatory response syndrome criteria and their association with sepsis in equine neonates

Background

The original equine sepsis score provided a method of identifying foals with sepsis. New variables associated with sepsis have been evaluated, but the sepsis score has not been updated.

Objectives

To evaluate the sensitivity and specificity of 2 updated sepsis scores and the systemic inflammatory response syndrome (SIRS) criteria in regard to detecting sepsis in foals.

Animals

Two‐hundred and seventy‐three ill foals and 25 healthy control foals.

Methods

Historical, physical examination, and clinicopathologic findings were used to calculate the original sepsis score and 2 updated sepsis scores. SIRS criteria were also evaluated. Sepsis scores and positive SIRS scores were statistically compared to foals with sepsis.

Results

One‐hundred and twenty‐six foals were septic and 147 sick‐nonseptic. The original and updated sepsis scores were significantly higher in septic foals as compared to sick‐nonseptic and healthy foals. The sensitivity and specificity of the updated sepsis scores to predict sepsis were not significantly better than those of the original sepsis score. One‐hundred and twenty‐seven of 273 (46.5%) foals met the original SIRS criteria and 88/273 (32%) foals met the equine neonatal SIRS criteria. The original SIRS criteria had similar sensitivity and specificity for predicting sepsis as did the 3 sepsis scores in our study.

Conclusions and Clinical Importance

The updated sepsis scores did not provide improved ability in predicting sepsis. Fulfilling the original SIRS criteria provided similar sensitivity and specificity in predicting sepsis as the modified sepsis score and might serve as a diagnostic aid in identifying foals at risk for sepsis.

Clinical utility of an optimised multiplex real-time PCR assay for the identification of pathogens causing sepsis in Vietnamese patients

INTRODUCTION

For the identification of bacterial pathogens, blood culture is still the gold standard diagnostic method. However, several disadvantages apply to blood cultures, such as time and rather large volumes of blood sample required. We have previously established an optimised multiplex real-time PCR method in order to diagnose bloodstream infections.

MATERIAL AND METHODS

In the present study, we evaluated the diagnostic performance of this optimised multiplex RT-PCR in blood samples collected from 110 septicaemia patients enrolled at the 108 Military Central Hospital, Hanoi, Vietnam.

RESULTS

Positive results were obtained by blood culture, the Light Cylcler-based SeptiFast^® assay and our multiplex RT-PCR in 35 (32%), 31 (28%), and 31 (28%) samples, respectively. Combined use of the three methods confirmed 50 (45.5%) positive cases of bloodstream infection, a rate significantly higher compared to the exclusive use of one of the three methods (P=0.052, 0.012 and 0.012, respectively). The sensitivity, specificity and area under the curve (AUC) of our assay were higher compared to that of the SeptiFast^® assay (77.4%, 86.1% and 0.8 vs. 67.7%, 82.3% and 0.73, respectively). Combined use of blood culture and multiplex RT-PCR assay showed a superior diagnostic performance, as the sensitivity, specificity, and AUC reached 83.3%, 100%, and 0.95, respectively. The concordance between blood culture and the multiplex RT-PCR assay was highest for Klebsiella pneumonia (100%), followed by Streptococcus spp. (77.8%), Escherichia coli (66.7%), Staphylococcus spp. (50%) and Salmonella spp. (50%). In addition, the use of the newly established multiplex RT-PCR assay increased the spectrum of identifiable agents (Acintobacter baumannii, 1/32; Proteus mirabilis, 1/32).

CONCLUSION

The combination of culture and the multiplex RT-PCR assay provided an excellent diagnostic accomplishment and significantly supported the identification of causative pathogens in clinical samples obtained from septic patients.

Maternal intrapartum antibiotic treatment continues to exert a bactericidal effect on the umbilical cord and peripheral venous blood of newborn infants

AIM

It is unclear whether maternal intrapartum antibiotic treatment (IAT) continues to exert a bactericidal effect on common pathogens in neonates. We studied the in vitro bactericidal effect of IAT on the cord and peripheral venous blood of newborn infants.

METHODS

Umbilical cord and peripheral venous blood from newborn infants born at Kaplan Medical Center, Israel, from April to October 2014 were studied for serum bactericidal titres against Group B Streptococcus (GBS) and Escherichia coli (E. coli) strains. We studied 60 samples of umbilical cord blood and 18 samples of peripheral venous blood from 60 newborn infants whose mothers received IAT. The controls were 10 samples of cord blood from mothers without IAT.

RESULTS

Cord blood exerted a bactericidal effect against 98% of GBS isolates but only 8% of E.coli isolates. Peripheral blood exerted a bactericidal effect against GBS in 94% of cases, but not against E. coli. No bactericidal effect was seen in the blood from the controls.

CONCLUSION

We found a continued bactericidal effect of umbilical cord blood and neonatal peripheral blood from newborn infants of IAT-treated mothers, mainly against GBS, but rarely against E. Coli. These findings may assist clinicians treating at-risk infants exposed to IAT.

Sepsis and septic shock: New definitions, new diagnostic and therapeutic approaches

Sepsis and septic shock are common life-threatening pathologies associated with high mortality and substantial costs for healthcare system. Clinical guidelines and bundles for the management of patients with sepsis have recently been updated. Herein, we review the history of sepsis and related conditions definitions from the first consensus conference in 1991 to nowadays, the epidemiologic data resulting from worldwide studies on incidence and mortality, the diagnostic approaches including the microbiological assessment of infection and the use of several prognostic and diagnostic biomarkers and finally we review the main therapeutic measures as the intravenous immunoglobulin therapy and the administration of appropriate antibiotic treatment to provide patients with sepsis a favourable outcome in the antibiotic-resistance era.

Molecular assays for the diagnosis of sepsis in neonates

BACKGROUND

Microbial cultures for diagnosis of neonatal sepsis have low sensitivity and reporting delay. Advances in molecular microbiology have fostered new molecular assays that are rapid and may improve neonatal outcomes.

OBJECTIVES

To assess the diagnostic accuracy of various molecular methods for the diagnosis of culture-positive bacterial and fungal sepsis in neonates and to explore heterogeneity among studies by analyzing subgroups classified by gestational age and type of sepsis onset and compare molecular tests with one another.

SEARCH METHODS

We performed the systematic review as recommended by the Cochrane Diagnostic Test Accuracy Working Group. On 19 January 2016, we searched electronic bibliographic databases (the Cochrane Library, PubMed (from 1966), Embase (from 1982), and CINAHL (from 1982)), conference proceedings of the Pediatric Academic Societies annual conference (from 1990), clinical trial registries (ClinicalTrials.gov, International Standard Randomised Controlled Trial Number (ISRCTN) registry, and World Health Organization (WHO) International Clinical Trials Platform (ICTRP) Search portal), and Science Citation Index. We contacted experts in the field for studies.

SELECTION CRITERIA

We included studies that were prospective or retrospective, cohort or cross-sectional design, which evaluated molecular assays (index test) in neonates with suspected sepsis (participants) in comparison with microbial cultures (reference standard).

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed the methodologic quality of the studies and extracted data. We performed meta-analyses using the bivariate and hierarchical summary receiver operating characteristic (HSROC) models and entered data into Review Manager 5.

MAIN RESULTS

Thirty-five studies were eligible for inclusion and the summary estimate of sensitivity was 0.90 (95% confidence interval (CI) 0.82 to 0.95) and of specificity was 0.93 (95% CI 0.89 to 0.96) (moderate quality evidence). We explored heterogeneity by subgroup analyses of type of test, gestational age, type of sepsis onset, and prevalence of sepsis and we did not find sufficient explanations for the heterogeneity (moderate to very low quality evidence). Sensitivity analyses by including studies that analyzed blood samples and by good methodology revealed similar results (moderate quality evidence).

AUTHORS' CONCLUSIONS

Molecular assays have the advantage of producing rapid results and may perform well as 'add-on' tests.

Utility of 16S rRNA PCR performed on clinical specimens in patient management

BACKGROUND

Broad-range 16S rRNA PCR can be used for the detection and identification of bacteria from clinical specimens in patients for whom there is a high suspicion of infection and cultures are negative. The aims of this study were (1) to compare 16S rRNA PCR results with microbiological culture results, (2) to assess the utility of 16S rRNA PCR with regard to antimicrobial therapy, and (3) to compare the yield of 16S rRNA PCR for different types of clinical specimen and to perform a cost analysis of the test.

METHODS

A retrospective study was performed on different clinical specimens which had 16S performed over 3 years (2012-2015). Standard microbiological cultures were performed on appropriate media, as per the laboratory protocol. Patient clinical and microbiological data were obtained from the electronic medical records and laboratory information system, respectively. 16S rRNA PCR was performed in a reference laboratory using a validated method for amplification and sequencing. The outcomes assessed were the performance of 16S rRNA PCR, change of antimicrobials (rationalization, cessation, or addition), and duration of therapy. Concordance of 16S rRNA PCR with bacterial cultures was also determined for tissue specimens.

RESULTS

Thirty-two patients were included in the study, for whom an equal number of specimens (n=32) were sent for 16S rRNA PCR. 16S rRNA PCR could identify an organism in 10 of 32 cases (31.2%), of which seven were culture-positive and three were culture-negative. The sensitivity was 58% (confidence interval (CI) 28.59-83.5%) and specificity was 85% (CI 61.13-96%), with a positive predictive value of 70% (CI 35.3-91.9%) and negative predictive value of 77.2% (CI 54.17-91.3%). Antimicrobial therapy was rationalized after 16S rRNA PCR results in five patients (15.6%) and was ceased in four based on negative results (12.5%). Overall the 16S rRNA PCR result had an impact on antimicrobial therapy in 28% of patients (9/32). The highest concordance of 16S rRNA PCR with bacterial culture was found for heart valve tissue (80%), followed by joint fluid/tissue (50%).

CONCLUSIONS

Despite the low diagnostic yield, results of 16S rRNA PCR can still have a significant impact on patient management due to rationalization or cessation of the antimicrobial therapy. The yield of 16S rRNA PCR was highest for heart valves.

Clinical Significance of Molecular Diagnostic Tools for Bacterial Bloodstream Infections: A Systematic Review

Bacterial bloodstream infection (bBSI) represents any form of invasiveness of the blood circulatory system caused by bacteria and can lead to death among critically ill patients. Thus, there is a need for rapid and accurate diagnosis and treatment of patients with septicemia. So far, different molecular diagnostic tools have been developed. The majority of these tools focus on amplification based techniques such as polymerase chain reaction (PCR) which allows the detection of nucleic acids (both DNA and small RNAs) that are specific to bacterial species and sequencing or nucleic acid hybridization that allows the detection of bacteria in order to reduce delay of appropriate antibiotic therapy. However, there is still a need to improve sensitivity of most molecular techniques to enhance their accuracy and allow exact and on time antibiotic therapy treatment. In this regard, we conducted a systematic review of the existing studies conducted in molecular diagnosis of bBSIs, with the main aim of reporting on clinical significance and benefits of molecular diagnosis to patients. We searched both Google Scholar and PubMed. In total, eighteen reviewed papers indicate that shift from conventional diagnostic methods to molecular tools is needed and would lead to accurate diagnosis and treatment of bBSI.

A Randomized, Double-Blind, Placebo-Controlled Trial: The Efficacy of Multispecies Probiotic Supplementation in Alleviating Symptoms of Irritable Bowel Syndrome Associated with Constipation

Background and Aim. The efficacy of supplementation treatment with two multispecies probiotic formulates on subjects diagnosed with IBS-C and the assessment of their gut microbiota were investigated. Methods. A randomized, double-blind, three-arm parallel group trial was carried out on 150 IBS-C subjects divided into three groups (F_1, F_2, and F_3). Each group received a daily oral administration of probiotic mixtures (for 60 days) F_1 or F_2 or placebo F_3, respectively. Fecal microbiological analyses were performed by species-specific qPCR to assess the different amount of probiotics. Results. The percentage of responders for each symptom was higher in the probiotic groups when compared to placebo group during the treatment period (t60) and was maintained quite similar during the follow-up period (t90). Fecal analysis demonstrated that probiotics of the formulations increased during the times of treatment only in fecal DNA from subjects treated with F_1 and F_2 and not with F_3, and the same level was maintained during the follow-up period. Conclusions. Multispecies probiotic supplementations are effective in IBS-C subjects and induce a different assessment in the composition of intestinal microbiota. This clinical study is registered with the clinical study registration number ISRCTN15032219.

Ending preventable maternal and newborn deaths due to infection

Over 300,000 maternal deaths occur each year, 11% of which are thought to be due to infectious causes, and approximately one million newborns die within the first week of life annually due to infectious causes. Infections in pregnancy may result in a variety of adverse obstetrical outcomes, including preterm delivery, pre-labor rupture of membranes, stillbirth, spontaneous abortion, congenital infection, and anomalies. This paper reviews the burden of disease due to key infections and their contribution to maternal, perinatal, and newborn morbidity and mortality, as well as key interventions to prevent maternal and newborn deaths related to these infections. Research needs include more accurate clinical and microbiologic surveillance systems, validated risk stratification strategies, better point-of-care testing, and identification of promising vaccine strategies.

Syndrome Evaluation System (SES) versus Blood Culture (BACTEC) in the Diagnosis and Management of Neonatal Sepsis--A Randomized Controlled Trial

OBJECTIVE

To compare the clinical outcome of a multiplex polymerase chain reaction (PCR) based molecular diagnostic method -- Syndrome Evaluation System (SES) directed treatment strategy vs. standard of care (blood culture) directed treatment strategy for neonatal sepsis.

METHODS

This randomized controlled trial (RCT) included 385 neonates with sepsis who were randomized into two groups -- SES and control (BACTEC). Both tests were performed for all the neonates. However, in the SES group, the results of SES test were revealed to the treating clinicians, while in the control group, SES results were withheld. Two ml of blood was drawn from each baby. One aliquot was sent for blood culture, whereas the remaining aliquot was sent for SES. Babies were then administered empirical IV antibiotics and given supportive care. Further antibiotic changes, if required were done in SES and control groups based on their respective reports. The microbiological profile, immediate outcome, duration of hospital stay, number of antibiotics used and readmission within a month in both groups were compared.

RESULTS

SES was better than BACTEC in identifying the causative organism in both the groups (68 % vs. 18 % in SES group and 72 % vs. 18 % in control group). SES had 100 % concordance with blood culture by BACTEC. Detection of bacteria and fungi were four and ten-fold higher respectively with SES when compared to BACTEC culture. Microbiological diagnosis was rapid with SES compared to BACTEC (7 h vs. 72 h). Treatment based on SES resulted in significantly less mortality (3 % vs. 18 %). Readmission rate, duration of hospital stay and change in antibiotics were also significantly less in SES group.

CONCLUSIONS

This new molecular based diagnostic system (SES) helps in rapid and accurate diagnosis of neonatal sepsis and reduces mortality and morbidity in affected neonates.

Real-time polymerase chain reaction and culture in the diagnosis of invasive group B streptococcal disease in infants: a retrospective study

Group B streptococcus (GBS) is a leading cause of invasive disease in infants. Accurate and rapid diagnosis is crucial to reduce morbidity and mortality. Real-time polymerase chain reaction (PCR) targeting the dltR gene was utilised for the direct detection of GBS DNA in blood and cerebrospinal fluid (CSF) from infants at an Irish maternity hospital. A retrospective review of laboratory and patient records during the period 2011-2013 was performed in order to evaluate PCR and culture for the diagnosis of invasive GBS disease. A total of 3570 blood and 189 CSF samples from 3510 infants had corresponding culture and PCR results. Culture and PCR exhibited concordance in 3526 GBS-negative samples and 13 (25%) GBS-positive samples (n = 53). Six (11%) and 34 (64%) GBS-positive samples were positive only in culture or PCR, respectively. Culture and PCR identified more GBS-positive infants (n = 47) than PCR (n = 43) or culture (n = 16) alone. Using culture as the reference standard, the sensitivity, specificity, and positive and negative predictive values for PCR on blood samples were 71.4%, 99.2%, 25% and 99.9%, and for CSF samples, they were 60%, 97.8%, 42.9% and 98.9%, respectively. The sensitivity and positive predictive values were improved (blood: 84.6% and 55%; CSF: 77.8% and 100%, respectively) when maternal risk factors and other laboratory test results were considered. The findings in this study recommend the use of direct GBS real-time PCR for the diagnosis of GBS infection in infants with a clinical suspicion of invasive disease and as a complement to culture, but should be interpreted in the light of other laboratory and clinical findings.

Markedly raised levels of C-reactive protein are associated with culture-proven sepsis or necrotising enterocolitis in extremely preterm neonates

AIM

A serious inflammatory process is suspected when C-reactive protein (CRP) is very high, and we established the causes and outcomes when CRP was >100 mg/L in neonates.

METHODS

We retrospectively reviewed all 277 episodes where CRP exceeded 100 mg/L between January 2007 and December 2011 at a tertiary neonatal unit.

RESULTS

Of the 6025 neonates admitted during the study period, 258 had CRP >100 mg/L at least once. The overall mortality rate was 44/258 (17%); 36 died within 7 days of CRP >100 mg/L, and 34 were extremely preterm infants. CRP exceeded 100 mg/L in 106 infants within the first 3 days of life - 74 term, 25 preterm and seven extremely preterm - with no infection identified in 81%. In contrast, infections were found in 87% of the 171 episodes from day four of life - 129 extremely preterm, 23 preterm and 19 term - predominantly coagulase-negative staphylococcus sepsis and necrotising enterocolitis.

CONCLUSION

Markedly elevated CRP in the first 3 days of life was most likely to affect term neonates (74/106) with no infectious cause (81%). However, CRP >100 mg/L from the fourth day of life was most likely to affect extremely preterm neonates (129/171) and have an infectious cause (87%).

16S Ribosomal Ribonucleic Acid Gene Polymerase Chain Reaction in the Diagnosis of Bloodstream Infections: A Systematic Review and Meta-Analysis

Objective

We aim to evaluate the accuracy of the 16S ribosomal ribonucleic acid (rRNA) gene polymerase chain reaction (PCR) test in the diagnosis of bloodstream infections through a systematic review and meta-analysis.

Methods

A computerized literature search was conducted to identify studies that assessed the diagnostic value of 16S rRNA gene PCR test for bloodstream infections. Study quality was assessed using the revised Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool. We calculated the sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR) and their 95% confidence intervals (95% CI) for each study. Summary receiver operating characteristic (SROC) curve was used to summarize overall test performance. Statistical analysis was performed in Meta-DiSc 1.4 and Stata/SE 12.0 software.

Results

Twenty-eight studies were included in our meta-analysis. Using random-effect model analysis, the pooled sensitivity, specificity, PLR, NLR, and DOR were 0.87 (95% CI, 0.85–0.89), 0.94 (95% CI, 0.93–0.95), 12.65 (95% CI, 8.04–19.90), 0.14 (95% CI, 0.08–0.24), and 116.76 (95% CI, 52.02–262.05), respectively. The SROC curve indicated that the area under the curve (AUC) was 0.9690 and the maximum joint sensitivity and specificity (Q*) was 0.9183. In addition, heterogeneity was statistically significant but was not caused by the threshold effect.

Conclusion

Existing data suggest that 16S rRNA gene PCR test is a practical tool for the rapid screening of sepsis. Further prospective studies are needed to assess the diagnostic value of PCR amplification and DNA microarray hybridization of 16S rRNA gene in the future.

Therapeutic hypothermia delays the C-reactive protein response and suppresses white blood cell and platelet count in infants with neonatal encephalopathy

BACKGROUND

Therapeutic hypothermia (HT) delays the cytokine response in infants with neonatal encephalopathy (NE).

OBJECTIVE

To determine if HT delayed the C-reactive protein (CRP) response and altered white blood cell (WBC), neutrophil and platelet count course during the first week of life in infants with NE.

DESIGN

Retrospective cohort study.

SETTING

Regional neonatal intensive care unit, UK.

PATIENTS

104 term infants with NE (38 normothermia (NT) and 66 HT) born between 1998 and 2010. Infants not exposed to prenatal sepsis risk factors were classified as group 'A' and exposed infants to group 'B'. CRP >10 mg/L was defined as significant response.

MAIN OUTCOME MEASURES

Time to CRP >10 mg/L, peak CRP, WBC, neutrophil and platelet count.

RESULTS

Blood cultures were negative in all the infants. In babies who had CRP response, HT delayed time to CRP >10 mg/L (median (95% CI): group A, HT: 36 h (28.3 to 48.0); NT: 24 h (0.0 to 24.0); p=0.001; group B, HT: 30 h (15.2 to 56.8); NT: 12 h (0.0 to 24.0); p=0.009) and time to peak CRP (median (95% CI): group A, HT: 60 h (60.0 to 72.0); NT: 36 h (0.0 to 48.0); p=0.001; group B, HT: 84 h (62.1 to 120.0); NT: 24 h (0.0 to 36.0); p=0.001). Compared with NT, HT was associated with reduction in slope of CRP elevation by 0.5 (95% CI 0.04 to 0.97), WBC by 2.18×10(9)/L (95% CI 0.002 to 4.35) and platelet count by 32.3×10(9)/L (95% CI 2.75 to 61.8) independent of exposure to sepsis risk, meconium aspiration and severity of asphyxia.

CONCLUSIONS

Therapeutic hypothermia delayed the initiation of CRP and its peak response, and depressed the WBC and platelet count compared with NT.

Early-onset neonatal sepsis

Early-onset sepsis remains a common and serious problem for neonates, especially preterm infants. Group B streptococcus (GBS) is the most common etiologic agent, while Escherichia coli is the most common cause of mortality. Current efforts toward maternal intrapartum antimicrobial prophylaxis have significantly reduced the rates of GBS disease but have been associated with increased rates of Gram-negative infections, especially among very-low-birth-weight infants. The diagnosis of neonatal sepsis is based on a combination of clinical presentation; the use of nonspecific markers, including C-reactive protein and procalcitonin (where available); blood cultures; and the use of molecular methods, including PCR. Cytokines, including interleukin 6 (IL-6), interleukin 8 (IL-8), gamma interferon (IFN-γ), and tumor necrosis factor alpha (TNF-α), and cell surface antigens, including soluble intercellular adhesion molecule (sICAM) and CD64, are also being increasingly examined for use as nonspecific screening measures for neonatal sepsis. Viruses, in particular enteroviruses, parechoviruses, and herpes simplex virus (HSV), should be considered in the differential diagnosis. Empirical treatment should be based on local patterns of antimicrobial resistance but typically consists of the use of ampicillin and gentamicin, or ampicillin and cefotaxime if meningitis is suspected, until the etiologic agent has been identified. Current research is focused primarily on development of vaccines against GBS.

Molecular diagnosis of sepsis: New aspects and recent developments

By shortening the time to pathogen identification and allowing for detection of organisms missed by blood culture, new molecular methods may provide clinical benefits for the management of patients with sepsis. While a number of reviews on the diagnosis of sepsis have recently been published we here present up-to-date new developments including multiplex PCR, mass spectrometry and array techniques. We focus on those techniques that are commercially available and for which clinical studies have been performed and published.

Four assay designs and on-chip calibration: gadgets for a sepsis protein array

A protein microarray for the early stage diagnosis of sepsis that allows the simultaneous detection of C-reactive protein (CRP) (2-200 μg/mL), procalcitonin (PCT) (0.2-50 ng/mL), and interleukin 6 (IL-6) (2-2000 pg/mL) has been developed. To enable the parallel detection of the differently abundant analytes, the low binding affinity between CRP and phosphocholine is exploited in a "low-sensitive" sandwich assay for CRP. The calibration is integrated directly on the chip resulting in a "one patient-one array" format, to provide a user-friendly and rapid diagnostic tool. Four different assay designs are introduced: (I) the classical assay that works with biotin-streptavidin chemistry, (II) the rapid assay that is performed in a single detection step, and two ultrasensitive assay designs accomplished either by (III) an enzymatic or (IV) an antibody mediated amplification resulting in high density labeling. The assay designs were evaluated by the repetitive measurement of low, medium, and high concentration levels of commercially available certified control sera. The precision was similar across all assay designs (coefficient of variation (CV), CVintra: 8-14%; CVinter: 18-34%), while the sensitivity (limits of detection (LODs)) increased by 1 order of magnitude for the ultrasensitive assays (III, IV) and the accuracy was analyte dependent but best for the classical (I) and the antibody amplified (IV) assays.

A microdevice for rapid optical detection of magnetically captured rare blood pathogens

Sepsis diagnosis requires development of methods to identify rare pathogen cells in small samples of human blood. Magnetic beads functionalized with pathogen-binding ligands have been used to rapidly isolate microbes from blood; however, it is commonly difficult to optically detect the captured species because the excess numbers of beads required for pathogen binding physically interfere with light transmission after they have been concentrated. Here we describe a microdevice that uses microfluidics combined with optimized magnetic field concentrators and magnetic beads coated with a generic blood opsonin to efficiently capture unknown blood pathogens and spread them into a thin layer suitable for automated optical detection. Using this device, we have been able to detect fungal pathogens in less than three hours after sample collection compared to days with current technology, and with an extremely high sensitivity (<1 cell mL(-1) of human blood).

Rapid assay to assess colonization patterns following in-vivo probiotic ingestion

Background

Colonization of the intestine with some microorganisms has been shown to have beneficial health effects. The association of bacteria with its human host starts soon after birth; however in infants born prematurely establishment of normal intestinal flora is interrupted with colonization with potential pathogenic organisms Probiotic supplementation may therefore be beneficial to the health of preterm infants. As most probiotic organisms are difficult to culture, confirmation of their colonization after supplementation is difficult. In this study, rapid qPCR assays for detection of presence of probiotic species in the intestine by faecal sampling is described in both preterm infant and adult participants.

Findings

Probiotic colonization was determined using qPCR directed at amplification of organisms present in the ingested probiotic Streptococcus thermophilus, Bifidobacterium animalis subsp. lactis and B. longum subsp. infantis. Overall, differential detection of probiotic strains in faeces were found between adult and preterm infants, with 50% of infants continuing to shed at least two probiotic strains three weeks after probiotic ingestion had ceased.

Conclusions

This study demonstrated rapid assessment of the preterm infant gut for colonization with probiotic strains using real-time PCR. This method would be of great importance in studies of probiotics in prevention of diseases and adverse clinical outcomes.

Neonatal sepsis due to coagulase-negative staphylococci

Neonates, especially those born prematurely, are at high risk of morbidity and mortality from sepsis. Multiple factors, including prematurity, invasive life-saving medical interventions, and immaturity of the innate immune system, put these infants at greater risk of developing infection. Although advanced neonatal care enables us to save even the most preterm neonates, the very interventions sustaining those who are hospitalized concurrently expose them to serious infections due to common nosocomial pathogens, particularly coagulase-negative staphylococci bacteria (CoNS). Moreover, the health burden from infection in these infants remains unacceptably high despite continuing efforts. In this paper, we review the epidemiology, immunological risk factors, diagnosis, prevention, treatment, and outcomes of neonatal infection due to the predominant neonatal pathogen CoNS.

How can the microbiologist help in diagnosing neonatal sepsis?

Neonatal sepsis can be classified into two subtypes depending upon whether the onset of symptoms is before 72 hours of life (early-onset neonatal sepsis—EONS) or later (late-onset neonatal sepsis—LONS). These definitions have contributed greatly to diagnosis and treatment by identifying which microorganisms are likely to be responsible for sepsis during these periods and the expected outcomes of infection. This paper focuses on the tools that microbiologist can offer to diagnose and eventually prevent neonatal sepsis. Here, we discuss the advantages and limitation of the blood culture, the actual gold standard for sepsis diagnosis. In addition, we examine the utility of molecular techniques in the diagnosis and management of neonatal sepsis.

Molecular assays in the diagnosis of neonatal sepsis: a systematic review and meta-analysis

BACKGROUND

Microbial cultures for diagnosis of neonatal sepsis suffer from low sensitivity and reporting delay. Advances in molecular microbiology have fostered new molecular assays that are rapid and may improve neonatal outcomes.

OBJECTIVES

We assessed whether molecular assays have sufficient sensitivity (>0.98) and specificity (>0.95) to replace microbial cultures in the diagnosis of neonatal sepsis and explored heterogeneity by use of subgroup analyses based on the type of assay, gestational age of the neonate, and type of sepsis onset.

METHODS

We performed the systematic review as recommended by the Cochrane Diagnostic Test Accuracy Working Group. Electronic bibliographic databases, conference abstracts, personal files, and reference lists of identified articles were searched. We included studies of case-control or consecutive series design, which evaluated molecular assays (index test) in neonates with suspected sepsis (participants) in comparison with microbial cultures (reference standard). Two reviewers independently assessed the methodologic quality of the studies and extracted data.

RESULTS

A bivariate random-effects model was used for meta-analysis of the 23 included studies, and summary estimates of sensitivity and specificity with 95% confidence intervals (CIs) were generated. Mean sensitivity and specificity were 0.90 (95% CI: 0.78-0.95) and 0.96 (95% CI: 0.94-0.97), respectively. Real-time polymerase chain reaction (PCR) and broad-range conventional PCR had higher sensitivity and specificity than other assays. Sufficient data were not available to evaluate gestational-age and sepsis-type subgroups.

CONCLUSION

Molecular assays do not have sufficient sensitivity to replace microbial cultures in the diagnosis of neonatal sepsis but may perform well as "add-on" tests.