Microbial screening of unrelated cord blood units in a Chinese cord blood bank

Zhu, Li; Lv, H.-J.; Wang, Y.; Yang, Jiao; Ni, Bing‐Jie; Meng, Zhong-Hua

doi:10.1111/tme.12079

Cited by 8 publications

(14 citation statements)

References 21 publications

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“…However, according to the state of knowledge based on microbial culture, rather than next generation sequencing, most areas inside of the body in healthy man are physiologically sterile [1]. An example of such a sterile microenvironment would be blood, in which bacteria (microorganisms) appear only periodically, e.g.…”

Section: Introductionmentioning

confidence: 99%

Comprehensive detection and identification of bacterial DNA in the blood of patients with sepsis and healthy volunteers using next-generation sequencing method - the observation of DNAemia

Gosiewski

Ludwig-Gałęzowska

Huminska

et al. 2016

Eur J Clin Microbiol Infect Dis

138

122

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Blood is considered to be a sterile microenvironment, in which bacteria appear only periodically. Previously used methods allowed only for the detection of either viable bacteria with low sensitivity or selected species of bacteria. The Next-Generation Sequencing method (NGS) enables the identification of all bacteria in the sample with their taxonomic classification. We used NGS for the analysis of blood samples from healthy volunteers (n = 23) and patients with sepsis (n = 62) to check whether any bacterial DNA exists in the blood of healthy people and to identify bacterial taxonomic profile in the blood of septic patients. The presence of bacterial DNA was found both in septic and healthy subjects; however, bacterial diversity was significantly different (P = 0.002) between the studied groups. Among healthy volunteers, a significant predominance of anaerobic bacteria (76.2 %), of which most were bacteria of the order Bifidobacteriales (73.0 %), was observed. In sepsis, the majority of detected taxa belonged to aerobic or microaerophilic microorganisms (75.1 %). The most striking difference was seen in the case of Actinobacteria phyla, the abundance of which was decreased in sepsis (P < 0.001) and Proteobacteria phyla which was decreased in the healthy volunteers (P < 0.001). Our research shows that bacterial DNA can be detected in the blood of healthy people and that its taxonomic composition is different from the one seen in septic patients. Detection of bacterial DNA in the blood of healthy people may suggest that bacteria continuously translocate into the blood, but not always cause sepsis; this observation can be called DNAemia.Electronic supplementary materialThe online version of this article (doi:10.1007/s10096-016-2805-7) contains supplementary material, which is available to authorized users.

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Section: Introductionmentioning

confidence: 99%

Comprehensive detection and identification of bacterial DNA in the blood of patients with sepsis and healthy volunteers using next-generation sequencing method - the observation of DNAemia

Gosiewski

Ludwig-Gałęzowska

Huminska

et al. 2016

Eur J Clin Microbiol Infect Dis

138

122

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“…The small volume of FP samples (0.5 or 1.0 mL) generally used by CBBs might not be sufficient to ensure optimal microbial detection, whereas the use of higher inoculum volumes of stem cell concentrate increases the sensitivity of detection, especially when contamination levels are low . Many CBBs have tried to optimize microbial detection in CB by using plasma only or mixtures of CB by‐products . These methods yielded detection rates ranging from 21% to 79%.…”

Section: Discussionmentioning

confidence: 99%

“…Five bacterial species known to be associated with contamination of CBUs were used in this study . These bacteria either were obtained from the American Type Culture Collection (ATCC) ( Escherichia coli [ATCC 25922] and Staphylococcus epidermidis [ATCC 49134]) or were isolated in‐house from contaminated blood products or CBUs ( Klebsiella pneumoniae [CLI‐UL‐01], Streptococcus agalactiae [CLI‐LSPQ‐37], and Bacteroides fragilis [CLI‐LSPQ‐19]).…”

Section: Methodsmentioning

confidence: 99%

“…The lack of consensus standards led to CBBs developing their own method for microbial screening. Generally, a sample of the final volume‐reduced CB product is used for sterility testing; however, postprocessing plasma, red blood cell (RBC) fraction, a mixture of these by‐products, or a small volume of the final stem cell concentrate (which includes the cryopreservation solution) are also used for microbial screening . Moreover, inoculum volumes, culture bottles being used, as well as delays between CB processing, culture bottle inoculation, and culture launch vary substantially between CBBs.…”

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confidence: 99%

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

et al. 2017

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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 5 6 units per bacterial strain) characterized to contain inhibitory substances or not were inoculated (10 colonyforming 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 248C before inoculation in culture bottles and detection using the BacT/ALERT 3D system. RESULTS: Dilution of cell concentrates in RPMI-1640allowed 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. U mbilical cord blood (CB) transplantation is indicated for severely immunocompromised patients. These patients have a high risk of contracting infections associated with the transplant. Given the nonsterile collection environment and the numerous procedures carried out before transplantation, microbial contamination of cord blood units (CBUs) is more frequent than for any other blood product.1-3 Consequently, the efficient microbial screening of CB donations remains a primary safety concern for cord blood banks (CBBs) while also being required by international accreditation organizations, such as the American Association of Blood Banks and the Foundation for the Accreditation of Cellular Therapy. 4,5 The development of standardized procedures for microbial screening of CBUs is still being awaited. The lack of consensus standards led to CBBs developing their own method for microbial screening. Generally, a sample of the final volume-reduced CB product is used for sterility testing; however, postprocessing plasma, red blood cell (RBC) fraction, a mixture of these by-products, or a small volume of the final stem cell concentrate (which includes the cryopreservation solution) are also used for microbial ABBREVIATIONS: ATCC 5 American Ty...

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“…Microbial contamination of umbilical cord blood (CB) hematopoietic stem cell products can occur at different points during collection in hospital obstetric units or during processing at the cord blood bank, and could represent a serious safety risk for immunocompromised transplantation patients. The incidence of contaminated CB varies widely between centers with skin and vaginal flora organisms representing the majority of contaminants isolated from CB . As required by cellular therapy accrediting organizations, cell therapy products must be tested for microbial contamination…”

mentioning

confidence: 99%

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

et al. 2018

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Microbial screening of unrelated cord blood units in a Chinese cord blood bank

Cited by 8 publications

References 21 publications

Comprehensive detection and identification of bacterial DNA in the blood of patients with sepsis and healthy volunteers using next-generation sequencing method - the observation of DNAemia

Comprehensive detection and identification of bacterial DNA in the blood of patients with sepsis and healthy volunteers using next-generation sequencing method - the observation of DNAemia

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

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

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