Umbilical Cord Blood IgA Levels and Bacterial Profile in Preterm Neonates Born with Maternal Risk Factors for Early-Onset Neonatal Sepsis

OBJECTIVES

To investigate the IgA levels and bacterial profile in umbilical cord blood (UCB) samples of mothers with risk factors compared to those without risk factors; and to understand the link between UCB culture positivity and neonatal outcomes [early-onset sepsis (EOS) or death within 7 d of life].

METHODS

This is a pilot prospective case-control study. Mothers with preterm deliveries (gestational age <34 wk) were enrolled in two groups- Cases: Those with antenatal risk factors (prolonged duration of rupture of membranes of ≥24 h or chorioamnionitis) and controls: Those without these two risk factors. Serum IgA levels was assayed and microbiological culture was tested in UCB samples. 16S sequencing to determine the UCB microbiome was performed in a subset of samples (n = 15). Neonates were followed-up for the occurrence of EOS or death until 7 d of life.

RESULTS

Forty-nine mothers as cases and 50 mothers as controls were consecutively enrolled. No significant difference was observed in the IgA levels (60.5 vs. 58.1 mg/L; p = 0.71), neonatal blood culture positivity (4.1% vs. 8.0%; p = 0.41) and UCB culture positivity (30.6% vs. 26.0%; p = 0.61) in the two groups. No difference was observed between the groups in occurrence of EOS or death within 7 d of life. Proteobacteria, Firmicutes and Actinobacteria were the most abundant phyla. Serratia, Bifidobacterium, Collinsella, Meganomas and Blautia being the most common genera.

CONCLUSIONS

Cord blood IgA concentration could not differentiate the neonates at-risk of infection due to its presence in both the groups.

Maternal HIV status skews transcriptomic response in infant cord blood monocytes exposed to Bacillus Calmette--Guerín

OBJECTIVES

HIV-exposed uninfected (HEU) infants exhibit altered vaccine responses and an increased mortality compared with HIV-unexposed infants. Here, vaccine responses in HEU and HIV-unexposed cord blood monocytes (CBMs) were assessed following Bacillus Calmette--Guerín (BCG) treatment.

DESIGN

Innate responses to in-vitro BCG treatment were assessed through transcriptional profiling using CBMs obtained from a Nigerian cohort of HIV-infected and uninfected women.

METHODS

HIV-unexposed (n = 9) and HEU (n = 10) infant CBMs were treated with BCG and transcriptionally profiled with the Nanostring nCounter platform. Differential expression and pathway enrichment analyses were performed, and transcripts were identified with enhanced or dampened BCG responses.

RESULTS

Following BCG stimulation, several pathways associated with inflammatory gene expression were upregulated irrespective of HIV exposure status. Both HIV-unexposed and HEU monocytes increased expression of several cytokines characteristic of innate BCG responses, including IL1β, TNFα, and IL-6. Using differential expression analysis, we identified genes significantly upregulated in HEU compared with HIV-unexposed monocytes including monocyte chemokine CCL7 and anti-inflammatory cytokine TNFAIP6. In contrast, genes significantly upregulated in HIV-unexposed compared with HEU monocytes include chemokine CCL3 and cytokine IL23A, both of which influence anti-mycobacterial T-cell responses. Finally, two genes, which regulate prostaglandin production, CSF2 and PTGS2, were also more significantly upregulated in the HIV-unexposed cord blood indicating that inflammatory mediators are suppressed in the HEU infants.

CONCLUSION

HEU monocytes exhibit altered induction of several key innate immune responses, providing mechanistic insights into dysregulated innate response pathways that can be therapeutically targeted to improve vaccine responses in HEU infants.

Perinatal Gram-Positive Bacteria Exposure Elicits Distinct Cytokine Responses In Vitro

During pregnancy, infections caused by the gram-positive bacteria Enterococcus faecalis (E. faecalis), Streptococcus agalacticae (S. agalacticae), and Staphylococcus aureus (S. aureus) are major reasons for preterm labor, neonatal prematurity, meningitis, or sepsis. Here, we propose cytokine responses to bacterial infections by the immature perinatal immune system as central players in the pathogenesis of preterm birth and neonatal sepsis. We aimed to close the gap in knowledge about such cytokine responses by stimulating freshly isolated umbilical blood mononuclear cells (UBMC) with lysates of E. faecalis, S. agalacticae, and S. aureus collected from pregnant women in preterm labor. Bacterial lysates and, principally, S. aureus and S. agalacticae distinctly triggered most of the eleven inflammatory, anti-inflammatory, TH1/TH2 cytokines, and chemokines quantified in UBMC culture media. Chemokines depicted the most robust induction. Among them, MIP-1β was further enhanced in UBMC from female compered to male newborn infants. Due to its stability and high levels, we investigated the diagnostic value of IL-8. IL-8 was critically upregulated in cord blood of preterm neonates suffering from infections compared to gestational age-matched controls. Our results provide novel clues about perinatal immunity, underscoring a potential value of IL-8 for the timely detection of infections and suggesting that MIP-1β constitutes an early determinant of sex-specific immunity, which may contribute, e.g., to male's vulnerability to preterm birth.

Detection of microbial cell-free DNA in maternal and umbilical cord plasma in patients with chorioamnionitis using next generation sequencing

BACKGROUND

Chorioamnionitis has been linked to spontaneous preterm labor and complications such as neonatal sepsis. We hypothesized that microbial cell-free (cf) DNA would be detectable in maternal plasma in patients with chorioamnionitis and could be the basis for a non-invasive method to detect fetal exposure to microorganisms.

OBJECTIVE

The purpose of this study was to determine whether next generation sequencing could detect microbial cfDNA in maternal plasma in patients with chorioamnionitis.

STUDY DESIGN

Maternal plasma (n = 94) and umbilical cord plasma (n = 120) were collected during delivery at gestational age 28-41 weeks. cfDNA was extracted and sequenced. Umbilical cord plasma samples with evidence of contamination were excluded. The prevalence of microorganisms previously implicated in choriomanionitis, neonatal sepsis and intra-amniotic infections, as described in the literature, were examined to determine if there was enrichment of these microorganisms in this cohort. Specific microbial cfDNA associated with chorioamnionitis was first detected in umbilical cord plasma and confirmed in the matched maternal plasma samples (n = 77 matched pairs) among 14 cases of histologically confirmed chorioamnionitis and one case of clinical chorioamnionitis; 63 paired samples were used as controls. A correlation of rank of a given microorganism across maternal plasma and matched umbilical cord plasma was used to assess whether signals found in umbilical cord plasma were also present in maternal plasma.

RESULTS

Microbial DNA sequences associated with clinical and/or histological chorioamnionitis were enriched in maternal plasma in cases with suspected chorioamnionitis when compared to controls (12/14 microorganisms, p = 0.02). Analysis of the microbial cfDNA in umbilical cord plasma among the 1,251 microorganisms detectable with this assay identified Streptococcus mitis, Ureaplasma spp., and Mycoplasma spp. in cases of suspected chorioamnionitis. This assay also detected cfDNA from Lactobacillus spp. in controls. Comparison between maternal plasma and umbilical cord plasma confirmed these signatures were also present in maternal plasma. Unbiased analysis of microorganisms with significantly correlated signal between matched maternal plasma and umbilical cord plasma identified the above listed 3 microorganisms, all of which have previously been implicated in patients with chorioamnionitis (Mycoplasma hominis p = 0.0001; Ureaplasma parvum p = 0.002; Streptococcus mitis p = 0.007). These data show that the pathogen signal relevant for chorioamnionitis can be identified in both maternal and umbilical cord plasma.

CONCLUSION

This is the first report showing the detection of relevant microbial cell-free cfDNA in maternal plasma and umbilical cord plasma in patients with clinical and/or histological chorioamnionitis. These results may lead to the development of a specific assay to detect perinatal infections for targeted therapy to reduce early neonatal sepsis complications.

The Association Between Gestational Diabetes and Microbiota in Placenta and Cord Blood

Objective: Early life is a critical period for gut microbial development. It is still controversial whether there is placental microbiota during a healthy pregnancy. Gestational diabetes mellitus (GDM) is associated with increased risk of metabolic syndrome in the offspring, and the mechanisms are unclear. We sought to explore whether microbiota in placenta and cord blood may be altered in GDM. Methods: Placenta and cord blood samples were collected from eight GDM and seven euglycemic (control) term pregnancies in cesarean deliveries without evidence of clinical infections. The Illumina MiSeq Sequencing System was used to detect the microbiota based on the V3-V4 hypervariable regions of the 16S ribosomal RNA gene. Results: The microbiota were detectable in all placental samples. Comparing GDM vs. controls, there were more operational taxonomic units (OTUs) (mean ± SE = 373.63 ± 14.61 vs. 332.43 ± 9.92, P = 0.024) and higher ACE index (395.15 ± 10.56 vs. 356.27 ± 8.47, P = 0.029) and Chao index (397.67 ± 10.24 vs. 361.32 ± 8.87, P = 0.04). The placental microbiota was mainly composed of four phyla: Bacteroidetes, Firmicutes, Actinobacteria, and Proteobacteria at the phylum level and 10 dominant genera at the genus level in both GDM and controls. Despite the dominant similarity in microbiota composition, at the OTU level, the abundance of Ruminococcus, Coprococcus, Paraprevotella, and Lactobacillus were higher, whereas Veillonella was lower in the placentas of GDM vs. controls. The microbiota was detected in one of the 15 cord blood samples, and its components were similar as to the corresponding placental microbiota at both phylum and genus levels suggesting placental microbiota as the potential source. Conclusions: The most abundant phyla and genus of placental microbiota were similar in GDM and euglycemic pregnancies, but GDM was associated with higher diversity of placental microbiota. Further study is needed to confirm the existence of microbiota in cord blood in pregnancies without clinical infection.

Pentoxifylline Alone or in Combination with Gentamicin or Vancomycin Inhibits Live Microbe-Induced Proinflammatory Cytokine Production in Human Cord Blood and Cord Blood Monocytes In Vitro

Neonatal sepsis and its accompanying inflammatory response contribute to substantial morbidity and mortality. Pentoxifylline (PTX), a phosphodiesterase inhibitor which suppresses transcription and production of proinflammatory cytokines, is a candidate adjunctive therapy for newborn sepsis. We hypothesized that PTX decreases live microbe-induced inflammatory cytokine production in newborn blood. Cord blood was stimulated with live microorganisms commonly encountered in newborn sepsis (Escherichia coli, Staphylococcus aureus, Staphylococcus epidermidis, or Candida albicans) and simultaneously treated with antimicrobial agents (gentamicin, vancomycin, or amphotericin B) and/or clinically relevant concentrations of PTX. Microbial colony counts were enumerated by plating, supernatant cytokines were measured by multiplex assay, intracellular cytokines and signaling molecules were measured by flow cytometry, and mRNA levels were measured by quantitative reverse transcription-PCR. PTX inhibited concentration-dependent E. coli-, S. aureus-, S. epidermidis-, and C. albicans-induced tumor necrosis factor (TNF) and E. coli-induced interleukin-1β (IL-1β) production in whole blood, with greater suppression of proinflammatory cytokines in combination with antimicrobial agents. Likewise, PTX suppressed E. coli-induced monocytic TNF and IL-1β, whereby combined PTX and gentamicin led to significantly greater reduction of TNF and IL-1β. The anti-inflammatory effect of PTX on microbe-induced proinflammatory cytokine production was accompanied by inhibition of TNF mRNA expression and was achieved without suppressing the production of the anti-inflammatory IL-10. Of note, microbial colony counts in newborn blood were not increased by PTX. Our findings demonstrated that PTX inhibited microbe-induced proinflammatory cytokine production, especially when combined with antimicrobial agents, without enhancing microbial proliferation in human cord blood in vitro, thus supporting its utility as candidate adjunctive agent for newborn sepsis.

Development of a proof of principle for universal neutralization of antibiotics in cord blood by-products used for sterility testing

BACKGROUND

Bacterial contamination of cord blood (CB) represents a safety risk for transplantation patients. CB sterility testing at Canadian Blood Services' Cord Blood Bank is performed using a 1:1 mix of CB-derived plasma and red blood cells (RBCs). Culture bottles of an automated culture system, which lack antimicrobial neutralization properties, are used for bacterial screening of CB. This process is unsuitable for CB-containing antibiotics, potentially resulting in false-negative results. This study was aimed at developing a protocol for antibiotic neutralization in CB used for sterility testing.

STUDY DESIGN AND METHODS

Phase 1: four neutralizers-penicillinase, ion exchange resins L and A, lecithin + Tween80, and activated charcoal (AC)-were individually tested to neutralize penicillin or gentamicin in cultures of Staphylococcus epidermidis or Klebsiella pneumoniae, respectively, adjusted to 100 colony forming units/mL, in Müller-Hinton broth (MHB). Phase 2: combinations of penicillinase plus resin L or penicillinase plus AC were assayed for the simultaneous neutralization of both antibiotics in MHB. Phase 3: penicillinase plus resin L was used to neutralize both antibiotics in CB sterility testing samples (plasma + RBCs).

RESULTS

Phase 1: penicillin was neutralized by penicillinase and resin A, while gentamicin was neutralized by resin L and AC. Phase 2: the antibiotics were simultaneously neutralized by the two neutralizer combinations tested. Phase 3: neutralization of both antibiotics in CB was achieved with penicillinase and resin L.

CONCLUSION

A protocol for antibiotic neutralization in CB sterility testing samples has been successfully developed at Canadian Blood Services' Cord Blood bank. This in-house assay applies to any culture-based CB bacterial screening method.

Optimization of cord blood unit sterility testing: impact of dilution, analysis delay, and inhibitory substances

BACKGROUND

Different methods are used by cord blood banks to prepare samples for sterility testing. Suboptimal methods can result in the release of contaminated products. In our organization, samples are prepared by diluting the final product in RPMI-1640 medium. In this work, we have compared our method with different approaches to verify whether optimization should be sought.

STUDY DESIGN AND METHODS

Cord blood units (n = 6 units per bacterial strain) characterized to contain inhibitory substances or not were inoculated (10 colony-forming units/mL) with Streptococcus agalactiae, Staphylococcus epidermidis, Klebsiella pneumoniae, Escherichia coli, or Bacteroides fragilis. After plasma and red blood cell removal, stem cell concentrates were diluted in RPMI-1640, thioglycollate, or the unit's plasma. These products, as well as final product, plasma, and red blood cell fractions, were held from 0 to 72 hours at 20 to 24°C before inoculation in culture bottles and detection using the BacT/ALERT 3D system.

RESULTS

Dilution of cell concentrates in RPMI-1640 allowed bacterial detection in 93.3% of noninhibitory cord blood samples after a 24-hour storage period. Thioglycollate medium better promoted bacterial growth in inhibitory cord blood samples that were held for 72 hours before testing (66.7%) compared with RPMI-1640 (45.0%). Less than 33% of all spiked plasma samples were detected by the BacT/ALERT 3D system.

CONCLUSION

Diluting cord blood samples in culture medium containing bacterial growth promoting substances is a suitable option for sterility testing, whereas the use of plasma should be proscribed, because it might lead to false-negative results. Because inhibitory substances affect bacterial growth, inoculation of culture bottles should be done rapidly after sample preparation.

[NEW APPROACHES TO THE EARLY DIAGNOSIS OF INTRAUTERINE VIRAL INFECTIONS IN NEWBORNS]

The importance of intrauterine viral infections in newborns pathology remain incompletely understood, as there is the problem of early verification of the etiologic pathogen. The aim of the study was to develop diagnostic criteria for intrauterine viral infections by introducing rapid diagnostic methods, the study of perinatal factors, medical history, clinical course and laboratory data. Clinical and laboratory examination 834 mothers and their newborn patients with suspected intrauterine infection. We observed 224 children with verified intrauterine viral infection. Studied the history of perinatal risk factors, clinical features and laboratory data. Studies have shown that the predominant form of mixed infections (85.7%). On the basis of statistical methods developed diagnostic criteria and algorithm of differential diagnosis of all possible variants of infection. Testing diagnostic algorithm has shown high reliability of diagnostic criteria, which allows recommend them for clinical use.

Microbial Contaminants of Cord Blood Units Identified by 16S rRNA Sequencing and by API Test System, and Antibiotic Sensitivity Profiling

Over a period of ten months a total of 5618 cord blood units (CBU) were screened for microbial contamination under routine conditions. The antibiotic resistance profile for all isolates was also examined using ATB strips. The detection rate for culture positive units was 7.5%, corresponding to 422 samples.16S rRNA sequence analysis and identification with API test system were used to identify the culturable aerobic, microaerophilic and anaerobic bacteria from CBUs. From these samples we recovered 485 isolates (84 operational taxonomic units, OTUs) assigned to the classes Bacteroidia, Actinobacteria, Clostridia, Bacilli, Betaproteobacteria and primarily to the Gammaproteobacteria. Sixty-nine OTUs, corresponding to 447 isolates, showed 16S rRNA sequence similarities above 99.0% with known cultured bacteria. However, 14 OTUs had 16S rRNA sequence similarities between 95 and 99% in support of genus level identification and one OTU with 16S rRNA sequence similarity of 90.3% supporting a family level identification only. The phenotypic identification formed 29 OTUs that could be identified to the species level and 9 OTUs that could be identified to the genus level by API test system. We failed to obtain identification for 14 OTUs, while 32 OTUs comprised organisms producing mixed identifications. Forty-two OTUs covered species not included in the API system databases. The API test system Rapid ID 32 Strep and Rapid ID 32 E showed the highest proportion of identifications to the species level, the lowest ratio of unidentified results and the highest agreement to the results of 16S rRNA assignments. Isolates affiliated to the Bacilli and Bacteroidia showed the highest antibiotic multi-resistance indices and microorganisms of the Clostridia displayed the most antibiotic sensitive phenotypes.

Transplacental transfer of Azithromycin and its use for eradicating intra-amniotic ureaplasma infection in a primate model

BACKGROUND

Our goals were to describe azithromycin (AZI) pharmacokinetics in maternal plasma (MP), fetal plasma (FP), and amniotic fluid (AF) following intra-amniotic infection (IAI) with Ureaplasma in pregnant rhesus monkeys and to explore concentration-response relationships.

METHODS

Following intra-amniotic inoculation of Ureaplasma parvum, rhesus monkeys received AZI (12.5 mg/kg every 12 hours intravenously for 10 days; n = 10). Intensive pharmacokinetic sampling of MP, FP, and AF was scheduled following the first (ie, single) dose and the last (ie, multiple) dose. Noncompartmental and pharmacokinetic modeling methods were used.

RESULTS

The AF area under the concentration-time curve at 12 hours was 0.22 µg×h/mL following a single dose and 6.3 µg×h/mL at day 10. MP and AF accumulation indices were 8.4 and 19, respectively. AZI AF half-life following the single dose and multiple dose were 156 and 129 hours, respectively. The median MP:FP ratio in concomitantly drawn samples was 3.2 (range, 1.3-9.6; n = 9). Eradication of U. parvum occurred at 6.6 days, with a 95% effective concentration (EC95) of 39 ng/mL for the maximum AZI AF concentration.

CONCLUSIONS

Our study demonstrates that a maternal multiple-dose AZI regimen is effective in eradicating U. parvum IAI by virtue of intra-amniotic accumulation and suggests that antenatal therapy has the potential to mitigate complications associated with U. parvum infection in pregnancy, such as preterm labor and fetal sequelae.

Decreased pattern recognition receptor signaling, interferon-signature, and bactericidal/permeability-increasing protein gene expression in cord blood of term low birth weight human newborns

Background

Morbidity and mortality rates of low birth weight (LBW) newborns at term are higher than rates in normal birth weight (NBW) newborns. LBW newborns are at greater risk to acquire recurrent bacterial and viral infections during their first few weeks of life possibly as an outcome of compromised innate immune functions. As adaptive immunity is in a naive state, increased risk of infection of LBW as compared to NBW newborns may reflect impairments in innate immunity.

Methodology

To characterize the increased susceptibility to infections in LBW newborns we used microarray technology to identify differences in gene expression in LBW newborns (n = 8) compared to NBW newborns (n = 4) using cord blood. The results obtained from the microarray study were validated on a larger number of samples using real time RT-PCR (LBW = 22, NBW = 18) and western blotting (LBW = 12, NBW = 12). The Interferome database was used to identify interferon (IFN) signature genes and ingenuity pathway analysis identified canonical pathways and biological functions associated with the differentially expressed genes in LBW newborns. ELISAs for IFNs and bactericidal/permeability-increasing protein were performed in both LBW and NBW newborns and in adults (LBW = 18, NBW = 18, Adults  = 8).

Principal Findings

Upon microarray analysis, we identified 1,391 differentially expressed genes, of which, 1,065 genes were down-regulated and 326 genes were up-regulated in the LBW compared to NBW newborns. Of note, 70 IFN-signature genes were found to be significantly down-regulated in LBW compared to NBW newborns. Ingenuity pathway analysis revealed pattern recognition receptors signaling including Toll-Like Receptors (TLRs) -1, -5, and -8 genes and IFN signaling as the most significantly impacted pathways. Respiratory infectious diseases were the most significantly affected bio-functions in LBW newborns.

Conclusion and Significance

Diminished PRRs, IFN-signature, and BPI gene expression raises the possibility that impairments in these pathways contribute to the susceptibility of LBW term infants to infection.

Comparative microbial analysis of paired amniotic fluid and cord blood from pregnancies complicated by preterm birth and early-onset neonatal sepsis

BACKGROUND

16S rRNA-based genomic analyses have revolutionized our understanding of infectious diseases. Many cases which were recognized as "idiopathic" are now known to have an infectious etiology. Here, we present a proof-of-concept study to examine the microbial link between intra-amniotic infection (IAI) and early-onset neonatal sepsis (EONS).

RESULTS

Using culture independent methods, we analyzed paired amniotic fluid (AF) and cord blood (CB) samples from 36 singleton pregnancies complicated by preterm birth (PTB), IAI, and/or EONS. PTB cases were grouped as 1) Group 1- neonatal blood culture-positive EONS (n=6). 2) Group 2- neonatal blood culture-negative presumed EONS with positive IAI (n=16). 3) Group 3- neonatal blood culture-negative presumed EONS with no IAI (n=7); 4) Group 4- no EONS or IAI (n=7). In addition, samples from term healthy deliveries (n=8) served as technical controls. A total of 31 species (15 non-redundant) were identified in AF, of which only 1/3 were cultivated. Significantly fewer microorganisms were detected in CB, with a total of 18 species (7 non-redundant) identified, of which only 2 (Escherichia coli, Streptococcus agalactiae) were cultivated. Of those, Bergeyella, Fusobacterium nucleatum, and Sneathia sanguinegens had not been detected in EONS before. The novel species identified in AF by PCR include Peptoniphilus harei and Lachnospiraceae sp. The majority (72%) of CB species were also detected in the matching AF, with E. coli and F. nucleatum as the most prevalent. The 16S rRNA sequences of paired AF and CB were 99.9-100% identical, while no identical sequences were found between different pregnancies.

CONCLUSIONS

Previously unrecognized, uncultivated or difficult-to-cultivate species are implicated in EONS. Microbial species in paired AF and CB likely share the same infectious origin. Given its prevalence in EONS, F. nucleatum should be placed on the same importance scale as E. coli.

Evaluation of the sterility testing process of hematopoietic stem cells at Canadian Blood Services

BACKGROUND

Sterility testing of hematopoietic stem cells (HSCs) at The Canadian Blood Services Stem Cell Laboratory is performed using BacT/ALERT aerobic (SA) culture bottles. This study was conducted to verify the efficacy of this method and to assess the use of the BacT/ALERT aerobic (BPA) and anaerobic (BPN) culture bottles for microbial testing of HSCs.

STUDY DESIGN AND METHODS

HSC products, including cryopreserved apheresis peripheral blood, marrow, and cord blood and fresh cord blood, were spiked with four aerobic organisms including Staphylococcus epidermidis, Bacillus cereus, Pseudomonas aeruginosa, and Candida albicans, and the anaerobe Bacteroides fragilis at a target concentration of 100 colony-forming units (CFUs)/mL. One to 2 mL of pre- and postspiked samples was inoculated into SA, BPA, and BPN bottles in duplicate and incubated for 5 to 10 days. The presence of the testing organisms in positive culture bottles was confirmed by plating on blood agar.

RESULTS

The BacT/ALERT system detected the aerobic organisms in all HSCs in SA and BPA bottles within 34.1 hours while B. fragilis was detected only in BPN bottles within 68.6 hours. The mean recovered concentration of microorganisms in the HSC products ranged from 55 to 352 CFUs/mL with the exception of B. cereus, which was greater than 10(3) CFUs/mL.

CONCLUSION

This study shows that the current sterility testing process at the Canadian Blood Services Stem Cell Laboratory detected the tested aerobic but not the anaerobic microbial contaminants in HSCs. The ability of the BacT/ALERT system using BPA and BPN bottles to detect bacterial contamination in HSCs was also demonstrated.

Factors affecting microbial contamination rate of cord blood collected for transplantation

BACKGROUND

Collection and processing of cord blood (CB) is associated with significant risk of microbial contamination and hence relevant standards mandate microbial screening of the final product. This study aimed to determine the contamination rate and associated risk factors during 14 years of banking at the Sydney Cord Blood Bank.

STUDY DESIGN AND METHODS

CB was collected and processed using a closed system and tested for contamination using blood culture bottles (BacT/ALERT, bioMérieux) incubated for a minimum of 5 days. Four microbial screening methods were used with different combinations of inoculated bottles (adult or pediatric) and associated sample volumes (10 or 1 mL).

RESULTS

Of 13,344 CB units screened, 537 (4.0%) tested positive for contamination, with Bacteroides spp. (20.9%), Staphylococcus spp. (18.6%), and Propionibacterium spp. (13.7%) being the most common isolates. The contamination rate reduced from 10% in 1997 to 1.1% in 2009. Multivariate analysis demonstrated the following variables were independently associated with higher contamination rates: vaginal delivery, collection by obstetric staff, and use of an anaerobic bottle in addition to an aerobic bottle (which facilitated a larger sample inoculation volume than pediatric bottles).

CONCLUSIONS

This study demonstrates that contamination rates of CB collected for transplantation can be substantially reduced by collection after cesarean delivery and utilizing trained CB collection staff. These data also indicate that the common practice of testing using a pediatric (aerobic) bottle with its attendant small volume of the final CB product may be suboptimal for sensitive detection of contaminating anaerobic microbes.

M-ficolin concentrations in cord blood are related to circulating phagocytes and to early-onset sepsis

INTRODUCTION

The pattern-recognition molecule M-ficolin is synthesized by monocytes and neutrophils. M-ficolin activates the complement system in a manner similar to mannan-binding lectin (MBL), but little is known about its role in host defense. Neonates are highly vulnerable to bacterial sepsis, in particular, due to their decreased phagocytic function.

RESULTS

M-ficolin cord blood concentration was positively correlated with the absolute phagocyte count (ρ 0.51, P < 0.001) and with immature/total neutrophil ratio (ρ 0.34, P < 0.001). When comparing infants with sepsis and controls, a high M-ficolin cord blood concentration (>1,000 ng/ml) was associated with early-onset sepsis (EOS) (multivariate odds ratio 10.92, 95% confidence interval 2.21-54.02, P = 0.003). Experimental exposure of phagocytes isolated from adult donors to Escherichia coli resulted in a significant time- and dose-dependent release of M-ficolin.

DISCUSSION

In conclusion, M-ficolin concentrations were related to circulating phagocytes and EOS. Our results indicate that bacterial sepsis can trigger M-ficolin release by phagocytes. Future studies should investigate whether M-ficolin may be used as a marker of neutrophil activation during invasive infections.

METHODS

We investigated M-ficolin in 47 infants with culture-positive sepsis during the first 30 days of life (13 with EOS and in 94 matched controls. M-ficolin was measured in cord blood using time-resolved immunofluorometric assay (TRIFMA). Multivariate logistic regression was performed.

Does prenatal antibiotic therapy compromise the diagnosis of early-onset infection and management of the neonate?

AIM

To assess the impact of prenatal antibiotic treatment on procalcitonin (PCT) and C-reactive protein (CRP) concentrations in cord blood, and on the rate of positive neonatal blood cultures.

METHODS

Neonates with early-onset infection (Group A; n=46) were compared with healthy controls (Group B; n=240). We evaluated the relationship between prenatal antibiotic therapy and early-onset infection, and for interactions with antibiotic therapy in the neonate immediately after birth.

RESULTS

In the Group A antibiotics were administered significantly more often prenatally and more often to neonates just after birth. The percentage of negative blood cultures in infected neonates was higher when antibiotic treatment was instituted prenatally. Differences in cord blood PCT and CRP concentrations were significant between both groups and were independent of prenatal antibiotic treatment. Streptococcus agalactiae was the most frequent species.

CONCLUSIONS

Almost one-third of neonates present with early-onset infection in spite of prenatal antibiotic therapy. Cord blood PCT and CRP measurements may be helpful in the diagnosis of infection also in cases when antibiotic therapy was started prenatally. Prenatal antibiotic administration reduced the number of positive blood cultures in neonates with early-onset infection and was associated with a greater rate of antibiotic treatment after birth in neonates without infection.

Comparison of the Bactec 9240 and BacT/Alert blood culture systems for evaluation of placental cord blood for transfusion in neonates

The Bactec 9240 and the BacT/Alert blood culture systems were compared as a means for detection of bacterial contaminants in whole blood, concentrated red cells, and plasma preparations prepared from umbilical cord blood (UCB) samples. Ninety-two UCB units seeded with low levels of various bacteria were evaluated. In more than 50% of cases, growth was not detected in plasma using either system (P < 0.001). When concentrated red cells and whole blood were compared, the Bactec system detected bacterial growth consistently sooner than the BacT/Alert system in all seeded bacteria except Staphylococcus species in whole blood. The median lengths of time to detection (LTD) for whole blood and concentrated cells in BacT/Alert were 18.7 h and 18.5 h, respectively. The median LTD for the same blood fractions using the Bactec system were 16.05 h and 15.64 h. These differences in LTD by blood culture system and sample type were statistically significant (whole blood, P = 0.0449; concentrated cells, P = 0.0037). Based on the results of our study, we recommend the use of either concentrated red cells or whole blood for sterility testing in UCB samples. In our laboratory, the Bactec system compared to the BacT/Alert system was the superior method for rapid detection of bacterial contaminants in cord blood.

Incidence of invasive ureaplasma in VLBW infants: relationship to severe intraventricular hemorrhage

OBJECTIVE

As Ureaplasmas may be pathogens in preterm infants, this study was conducted to determine the incidence of invasive disease with Ureaplasma parvum and Ureaplasma urealyticum and the relationship with adverse outcomes in a prospective cohort of very low birth weight (VLBW) infants.

STUDY DESIGN

DNA was extracted from the cord or venous blood and cerebrospinal fluid (CSF) samples obtained from 313 VLBW infants. PCR was performed using primers for the mba gene to detect all 14 serovars and then repeated for all positive samples using species-specific primers.

RESULT

Ureaplasma species were detected in serum and/or CSF samples from 74 of 313 (23.6%) infants. U. parvum was the predominant species (70%). Presence of Ureaplasma was significantly associated with elevated interleukin-1beta in cord blood (odds ratio (OR) 2.6, 1.05 to 6.45, P=0.039). Ureaplasma serum-positive infants had a 2.3-fold increased risk of intraventicular hemorrhage > or =grade 3 (OR 2.50; 1.06 to 5.89, P=0.036).

CONCLUSION

Invasive Ureaplasma occurs commonly in VLBW infants and may increase the risk for severe intraventricular hemorrhage.

Microbial contamination of the Tzu-Chi Cord Blood Bank from 2005 to 2006

BACKGROUND

In total, 4502 units of cord blood (CB) were collected during a 2-year period from 2005 to 2006 by the Buddhist Tzu-Chi Stem Cells Center. The aim of this study was to analyze the incidence of microbial contamination and type of organism present in the cord blood. The clinical impact of microbial contamination on hematopoietic progenitor cell (HPC) grafts used for HPC transplantation is also discussed.

METHODS

First and second specimens were obtained for microbial assessment. These were collected in laboratory after cord blood collection and after cord blood unit manipulation, respectively. The samples were cultured and the results reviewed.

RESULTS

The overall incidence of microbiological contamination was 1.8% (82/4502). Three CB units were contaminated with two different organisms. Infectious organisms comprised 9.4% (8/85) of total isolated microbes. These infectious microorganisms were beta-Streptococci group B, Candida tropicalis and Staphylococcus aureus which were isolated in 6, 1 and 1 of CB units respectively. Escherichia coli, Bacteroides fragilis, Lactobacillus spp., Enterococcus, beta-Streptococcus Group B, Bacteroides valgatus, Corynebacterium spp., Klebsiella pneumonia and Peptococcus spp. were the most frequently encountered microorganisms. A higher contamination rate of the CB units was noted after vaginal delivery (2.16%) compared to caesarian section (0.85%) (p < 0.01).

CONCLUSIONS

Extensive training in CB collection, good procedures and good protocols can decrease the rate of microbial contamination. The use of a closed collecting system and an ex utero method have the advantage of a lower contamination rate. In our cord blood bank, we use a closed system but an in utero method. Similar to other studies, most of microorganisms reported here as contaminants are non-pathogenic.

Congenital toxoplasmosis in two health institutions in Trinidad

Toxoplasmosis is the most widespread zoonosis and an important human disease particularly in children where it could cause visual and neurological impairment and mental retardation. This study was conducted to determine the prevalence of toxoplasmosis, especially congenital toxoplasmosis in patients at two health institutions in Trinidad A total of 504 cord blood samples of newborn babies were collected: 174 from a women's hospital and 330 from a general hospital. In order to elicit aternal and prenatal risk factors for toxoplasmosis, mothers of the newborns completed a questionnaire. Enzyme-immuno assay (EIA) was used to detect IgG and IgM to Toxoplasma gondii. Overall, of 504 serum samples tested, 220 (43.7%) were seropositive for IgG while the prevalence of congenital toxoplasmosis as reflected by IgM was 0.4%. The prevalence of IgG and IgM by health institutions was not significantly different (p > 0.05; chi-square). The prevalence of toxoplasmosis using IgG was highest in neonates of mothers who were of East Indian descent (54.1%), had four children (52.9%), kept cats in households (47.7%), practised outdoor gardening (50.8%), consumed raw meat (66.7%), had experienced miscarriage(s) (47.3%), stillbirths (66.7%), or who had eye problem(s) (52.9%) and mental retardation (50.0%). The study prevalence of congenital toxoplasmosis revealed a high seroprevalence oftoxoplasmosis in neonates but there was 0.4% serological evidence of congenital disease. It indicates a need for sensitization of the population and healthcare workers and for follow-up of infected children for clinical evidence of the disease. This would be necessary to fully appreciate the impact of toxoplasmosis in Trinidad and Tobago. The differences from comparison groups were however not statistically significant (p > 0.05; chi-square).

Directed sibling cord blood banking for transplantation: the 10-year experience in the national blood service in England

Umbilical cord blood (UCB) is an important source of hematopoietic stem cells for transplantation. Although UCB is often collected from unrelated donors, directed umbilical cord blood (DCB) from sibling donors also provides an important source of UCB for transplantation. This report summarizes the experience in collection, testing, storage, and transplantation of DCB units by the National Blood Service for England and North Wales over 10 years. Eligibility for collection was based on an existing sibling suffering from a disease that may be treated by stem cell transplantation or a family history that could result in the birth of a sibling with a disease that could be treated by stem cell transplantation. Collections were made on the provision that the sibling's clinician was willing to financially support the collection and to take responsibility for medical review of the mother and potential recipient. Given the high investment in UCB banking and the introduction of new regulations and mandatory licensing under the European Union Tissues and Cells Directive and those proposed in the U.S., this report details the procedures that we have used for DCB donations, the outcome data where donations have been used for transplantation, and it provides some timely recommendations for best practices. Disclosure of potential conflicts of interest is found at the end of this article.

Pathogens in maternal blood and fetal cord blood using Q-PCR assay

OBJECTIVE

To evaluate the rates of infection of asymptomatic fetuses and mothers through fetal cord blood and maternal blood examination results.

MATERIALS AND METHODS

Quantitative PCR (Q-PCR) was used to detect pathogens in maternal peripheral blood and fetal cord blood after delivery of term pregnancy at Buddhist Tzu Chi Medical Center, Hualien, between July 2002 and June 2003.

RESULTS

We used Q-PCR to detect pathogens in 29 samples of maternal blood. The maternal hepatitis B virus (HBV) DNA detection rate was 51.72% (15/29); for human cytomegalovirus DNA, the detection rate was 10.34% (3/29) and for Chlamydia trachomatis DNA the detection rate was 3.45% (1/29). No Neisseria gonorrhoeae DNA was detected. Whereas, in 29 samples of paired fetal cord blood, the detection rates were 27.59% (8/29), 10.34% (3/29), and 3.45% (1/29) for HBV DNA, C. trachomatis DNA, and N. gonorrhoeae DNA, respectively. No human cytomegalovirus DNA was detected in fetal cord blood.

CONCLUSION

Our results revealed an unexpectedly high incidence of pathogens in fetal cord blood. Screening for the above pathogens in donor cord blood in cord blood banks using Q-PCR is strongly urged to decrease morbidity and mortality rates in fetal cord blood stem cell transplant recipients.

UC blood infection with clinical strains of Mycobacterium tuberculosis: a novel model

BACKGROUND

Use of unrelated cord blood transplantation (UCBT) is increasing, yet high rates of mortality secondary to infection remain a problem. We investigated the utility of using umbilical cord blood (UCB) as a model to study a naive cell population challenged by Mycobacterium tuberculosis.

METHODS

Mononuclear cells were isolated from nine UCB samples and infected with each of four distinct strains of M. tuberculosis. The isolates used were two highly transmissible clinical strains, the virulent laboratory strain H37Rv and a unique strain isolated from only one case (i.e. non-virulent). CFU were assessed at 3 h post-infection (day 0) and at day 7 to generate growth curves. Viability of the mononuclear cells was assessed prior to infection, 3 h post-infection and at days 3, 5 and 7 post-infection. IFN-gamma and TNF-alpha levels were determined at 24 h post-infection.

RESULTS

All three of the virulent strains demonstrated rapid growth in UCB cells that was significantly faster than the growth rate observed for the non-virulent unique isolate. There was no significant decrease in UCB cell viability after the 7-day incubation period regardless of infecting isolate. UCB cells secreted IFN-gamma in response to infection, with no significant difference related to infection with different isolates. However, there was a significant increase in the amount of TNF-alpha elicited following infection with the non-virulent isolate compared with the virulent isolates.

DISCUSSION

These results show that UCB can be used as a model to study infection, hopefully leading to new therapies for neonates and UCBT recipients.