Details
| Original language | English |
|---|---|
| Pages (from-to) | 131-144 |
| Number of pages | 14 |
| Journal | Applied Microbiology and Biotechnology |
| Volume | 104 |
| Issue number | 1 |
| Early online date | 28 Nov 2019 |
| Publication status | Published - Jan 2020 |
Abstract
The availability of bioresources is a precondition for life science research, medical applications, and diagnostics, but requires a dedicated quality management to guarantee reliable and safe storage. Anecdotal reports of bacterial isolates and sample contamination indicate that organisms may persist in liquid nitrogen (LN) storage tanks. To evaluate the safety status of cryocollections, we systematically screened organisms in the LN phase and in ice layers covering inner surfaces of storage tanks maintained in different biobanking facilities. We applied a culture-independent approach combining cell detection by epifluorescence microscopy with the amplification of group-specific marker genes and high-throughput sequencing of bacterial ribosomal genes. In the LN phase, neither cells nor bacterial 16S rRNA gene copy numbers were detectable (detection limit, 102 cells per ml, 103 gene copies per ml). In several cases, small numbers of bacteria of up to 104 cells per ml and up to 106 gene copies per ml, as well as Mycoplasma, or fungi were detected in the ice phase formed underneath the lids or accumulated at the bottom. The bacteria most likely originated from the stored materials themselves (Elizabethingia, Janthibacterium), the technical environment (Pseudomonas, Acinetobacter, Methylobacterium), or the human microbiome (Bacteroides, Streptococcus, Staphylococcus). In single cases, bacteria, Mycoplasma, fungi, and human cells were detected in the debris at the bottom of the storage tanks. In conclusion, the limited microbial load of the ice phase and in the debris of storage tanks can be effectively avoided by minimizing ice formation and by employing hermetically sealed sample containers.
Keywords
- Amplicon sequencing, Biobanking, Cryobank, Cryopreservation, Microbial contamination, Risk/quality management, Safe storage
ASJC Scopus subject areas
- Biochemistry, Genetics and Molecular Biology(all)
- Biotechnology
- Immunology and Microbiology(all)
- Applied Microbiology and Biotechnology
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In: Applied Microbiology and Biotechnology, Vol. 104, No. 1, 01.2020, p. 131-144.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Factors determining microbial colonization of liquid nitrogen storage tanks used for archiving biological samples
AU - Bajerski, F.
AU - Bürger, A.
AU - Glasmacher, Birgit
AU - Keller, E. R.J.
AU - Müller, K.
AU - Mühldorfer, K.
AU - Nagel, M.
AU - Rüdel, H.
AU - Müller, T.
AU - Schenkel, J.
AU - Overmann, J.
N1 - Funding information: This study was funded by the Alliance of German Cryobanks (Gemeinschaft Deutscher Kryobanken, GDK). This work was supported by ‘EUCOMM: Tools for Functional Annotation of the Mouse Genome’ (EUCOMMTOOLS) project - grant agreement no [FP7-HEALTH-F4-2010-261492] and ‘ExNet-0041-Phase2-3 („SyNErgy-HMGU“)‘ through the Initiative and Network Fund of the Helmholtz Association. Acknowledgments We gratefully acknowledge the support by Angelika Senula, Anika Methner, Doris Büchner, Julia Guewa, Katerina Zelena, Franziska Klann, Petra Henke, Javier Pascual and Johannes Sikorski for critical comments and statistical advice. Furthermore, we thank Martin Weingärtner for taking the samples at Fraunhofer IME.
PY - 2020/1
Y1 - 2020/1
N2 - The availability of bioresources is a precondition for life science research, medical applications, and diagnostics, but requires a dedicated quality management to guarantee reliable and safe storage. Anecdotal reports of bacterial isolates and sample contamination indicate that organisms may persist in liquid nitrogen (LN) storage tanks. To evaluate the safety status of cryocollections, we systematically screened organisms in the LN phase and in ice layers covering inner surfaces of storage tanks maintained in different biobanking facilities. We applied a culture-independent approach combining cell detection by epifluorescence microscopy with the amplification of group-specific marker genes and high-throughput sequencing of bacterial ribosomal genes. In the LN phase, neither cells nor bacterial 16S rRNA gene copy numbers were detectable (detection limit, 102 cells per ml, 103 gene copies per ml). In several cases, small numbers of bacteria of up to 104 cells per ml and up to 106 gene copies per ml, as well as Mycoplasma, or fungi were detected in the ice phase formed underneath the lids or accumulated at the bottom. The bacteria most likely originated from the stored materials themselves (Elizabethingia, Janthibacterium), the technical environment (Pseudomonas, Acinetobacter, Methylobacterium), or the human microbiome (Bacteroides, Streptococcus, Staphylococcus). In single cases, bacteria, Mycoplasma, fungi, and human cells were detected in the debris at the bottom of the storage tanks. In conclusion, the limited microbial load of the ice phase and in the debris of storage tanks can be effectively avoided by minimizing ice formation and by employing hermetically sealed sample containers.
AB - The availability of bioresources is a precondition for life science research, medical applications, and diagnostics, but requires a dedicated quality management to guarantee reliable and safe storage. Anecdotal reports of bacterial isolates and sample contamination indicate that organisms may persist in liquid nitrogen (LN) storage tanks. To evaluate the safety status of cryocollections, we systematically screened organisms in the LN phase and in ice layers covering inner surfaces of storage tanks maintained in different biobanking facilities. We applied a culture-independent approach combining cell detection by epifluorescence microscopy with the amplification of group-specific marker genes and high-throughput sequencing of bacterial ribosomal genes. In the LN phase, neither cells nor bacterial 16S rRNA gene copy numbers were detectable (detection limit, 102 cells per ml, 103 gene copies per ml). In several cases, small numbers of bacteria of up to 104 cells per ml and up to 106 gene copies per ml, as well as Mycoplasma, or fungi were detected in the ice phase formed underneath the lids or accumulated at the bottom. The bacteria most likely originated from the stored materials themselves (Elizabethingia, Janthibacterium), the technical environment (Pseudomonas, Acinetobacter, Methylobacterium), or the human microbiome (Bacteroides, Streptococcus, Staphylococcus). In single cases, bacteria, Mycoplasma, fungi, and human cells were detected in the debris at the bottom of the storage tanks. In conclusion, the limited microbial load of the ice phase and in the debris of storage tanks can be effectively avoided by minimizing ice formation and by employing hermetically sealed sample containers.
KW - Amplicon sequencing
KW - Biobanking
KW - Cryobank
KW - Cryopreservation
KW - Microbial contamination
KW - Risk/quality management
KW - Safe storage
UR - http://www.scopus.com/inward/record.url?scp=85075951338&partnerID=8YFLogxK
U2 - 10.1007/s00253-019-10242-1
DO - 10.1007/s00253-019-10242-1
M3 - Article
C2 - 31781817
AN - SCOPUS:85075951338
VL - 104
SP - 131
EP - 144
JO - Applied Microbiology and Biotechnology
JF - Applied Microbiology and Biotechnology
SN - 0175-7598
IS - 1
ER -