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ABSTRACT: Bacterial contamination of platelet concentrates (PCs) still represents an ongoing risk. As a result of septic complications, particularly observed with older PCs, the shelf life of PCs has been reduced in Germany to 4 days. In this study, bacterial screening of PCs by BactiFlow (BF) flow cytometry was introduced in three German blood services to evaluate the robustness and applicability of the assay. Results were used to discuss the potential for the extension of PC shelf life to 5 days.
A total of 1956 PCs were tested on days 4 or 5+ after PC production using the BF, whereas the BacT/Alert culture system served as reference method.
Two PCs were confirmed positive by culture only and were identified as Propionibacterium acnes and Staphylococcus species. Two PCs were confirmed positive for Streptococcus mitis by BF and culture. Additionally, two PCs were culture-positive only in one culture bottle (aerobic: S. mitis and anaerobic: S. hominis). Retrospective analysis of bacterial growth kinetics provide the indication that corresponding bacterial titres were most likely below the BF analytical detection limit (<150 CFU mL(-1) ) and had probably no transfusion relevance. All remaining specimens were tested negative.
Testing of PCs by BF was successfully implemented. The BF proved sufficient as a rapid screening method to improve PC safety. This study further provides data supporting the extension of PC shelf life to 5 days after negative BF testing on day 4.
Transfusion Medicine 06/2012; 22(4):262-71. · 1.14 Impact Factor
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Vox Sanguinis 01/2012; 102(4):365. · 2.86 Impact Factor
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ABSTRACT: Bacterial contamination of platelet concentrates still represents a major risk in transfusion medicine, and a variety of screening methods have been available to improve the safety of PCs. In the present study, the analytical quality of three different rapid screening methods (BactiFlow flow cytometry, Pan Genera Detection Assay, 23S rRNA RT-PCR) was evaluated in an inter-laboratory comparison in three different German blood services.
Samples were inoculated with different bacteria [Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli (two strains), Klebsiella pneumoniae (two strains), Enterobacter aerogenes (one strain), Serratia marcescens (one strain)] at different counts (4·5 × 10(3) -4·5 × 10(8) CFU/ml) alternating with negative samples in one transfusion facility. Samples were blinded with a random order for each screening method, shipped to partners and analysed immediately after receipt with different rapid screening methods.
The inter-laboratory comparison revealed that the BactiFlow assay and 23S rRNA RT-PCR-screening detected all samples correctly (positive: 12/12, negative: 8/8). The Pan Genera Detection Assay test detected only four of the positive samples. Four of the non-detected positive samples were below the assay's detection limit. Another four inoculated samples with comparatively high bacteria counts were detected false negative (E. coli (two strains): 9·87 × 10(5) and 2·10 × 10(7) CFU/ml, respectively, K. pneumoniae: 4·79 × 10(6) CFU/ml, S. aureus: 6·03 × 10(5) CFU/ml). All rapid screening methods revealed no false-positive results.
Both BactiFlow and 23S rRNA RT-PCR demonstrated a high sensitivity to detecting bacterial contamination in PCs. The Pan Genera Detection Assay had some shortcomings regarding sensitivity, especially for the detection of Gram-negative strains.
Vox Sanguinis 12/2011; 103(1):1-9. · 2.86 Impact Factor
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W K Roth,
M P Busch,
A Schuller,
S Ismay,
A Cheng,
C R Seed,
C Jungbauer,
P M Minsk,
D Sondag-Thull,
S Wendel, [......],
C Jennings,
E Notari,
S Stramer,
D Kessler,
C Hillyer,
H Kamel,
L Katz,
C Taylor,
S Panzer,
H W Reesink
Vox Sanguinis 09/2011; 102(1):82-90. · 2.86 Impact Factor
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ABSTRACT: The proposed predictive value of serum anti-myelin antibodies for the development of multiple sclerosis after a first clinically isolated syndrome was recently challenged.
To investigate myelin autoantibodies before first disease manifestation using different detection methods.
Patients with multiple sclerosis who had donated blood at a time prior to development of clinically isolated syndrome were identified via the German National Multiple Sclerosis Society. Control sera were obtained from age- and gender-matched blood donors. IgG-/IgM-antibodies against the extracellular part of native, cell surface-expressed myelin oligodendrocyte glycoprotein were detected by flow cytometry. Antibodies against linear epitopes were identified by immunoblot using recombinant myelin oligodendrocyte glycoprotein (aa1-125) and human myelin basic protein preparations.
Fifty eight serum samples from 25 patients covering an interval of 7.3 years-2 months prior to disease onset were available. Longitudinal investigations were performed in 19 patients (2-14 samples per patient, 7 years-2 months prior to disease onset). No significant differences in the prevalence or titres of anti-myelin antibodies were detected between sera of preclinical individuals and healthy donors by either flow cytometry or immunoblot. There was no correlation between interval before clinically isolated syndrome and autoantibody status. Occurrence of antibodies was not associated with symptomatology/severity of clinically isolated syndrome.
Neither anti-myelin autoantibodies against cell surface-expressed native myelin oligodendrocyte glycoprotein nor against linear epitopes have a predictive or discriminative role during the preclinical disease phase for developing clinically isolated syndrome or multiple sclerosis later in life.
Multiple Sclerosis 10/2010; 16(10):1189-92. · 4.26 Impact Factor
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ABSTRACT: In 1997 the German Red Cross (GRC) blood donor services introduced mini-pool nucleic acid testing (NAT) for human immunodeficiency virus (HIV)-1, hepatitis C virus (HCV) and hepatitis B virus (HBV) to increase blood safety. With the new cobas s 201/cobas TaqScreen MPX, a fully automated extraction method and a multiplex amplification system specifically adapted to the needs of blood donation services is available.
The cobas s 201 system was evaluated at the GRC BTS locations Hagen, Springe and Frankfurt. In phase A, the analytical sensitivity for the detection of HBV, HCV and HIV-1 was investigated and in phase B, at least 60,000 samples at each test site were screened in parallel with the MPX test on s 201 system and the existing routine mini-pool NAT system to compare the diagnostic specificity and the diagnostic sensitivity.
Comparable analytical sensitivities in a range of 1.6-3.6 IU/ml, 4.9-10.9 IU/ml and 14.7-26.6 IU/ml for HBV, HCV HIV, respectively, for the MPX test on s 201 system (95% probability based on probit analysis) were determined at all test sites. The diagnostic sensitivity was 99.8% and the diagnostic specificity was 99.85%.
The MPX test on s 201 system is a fully automated NAT system suitable for routine blood donor screening. The analytical sensitivity as well as the diagnostic sensitivity fulfilled all requirements of the Paul Ehrlich Institute for blood donor screening in mini-pools up to 96 donations per pool. A major benefit of the automated NAT system is the reduced personnel time and the extensive complete barcode-controlled process documentation.
Vox Sanguinis 09/2009; 98(1):37-46. · 2.86 Impact Factor
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ABSTRACT: Routine bacterial monitoring of apheresis platelet concentrates (APC) and pooled platelet concentrates (PPC) was introduced in two German blood services using culture and real-time reverse transcriptase (RT)-polymerase chain reaction (PCR). The results of testing are reviewed and used to discuss different strategies for detection of bacterial contamination of PCs.
Two thousand three hundred and sixty-two APCs and 1993 PPCs have been tested by real-time RT-PCR and the BacT/Alert automated culturing system using aerobic and anaerobic culture bottles. After standard processing of PCs and storage of 22-24 h at 20-24 degrees C with agitation, samples were taken under aseptic conditions. Reactive culture bottles were confirmed as positive and bacterial isolates were identified by 16S rRNA analysis and biochemical tests.
Seventeen of 2362 tested APCs were reactive in culture and one also in RT-PCR. Of these, 13 APCs were identified as initially positive as Staphylococcus warneri (n = 1, positive in aerobic and anaerobic culture), Propionibacterium acnes (n = 12, positive only in anaerobic culture) and four were initially reactive. Two of 1993 PPCs were initially reactive (anaerobic) and two more were confirmed positive (anaerobic) from a repeat culture and identified as P. acnes. All remaining specimens were tested negative.
Our study demonstrates that the predominant organisms implicated in platelet bacterial contamination are part of the human skin flora. Inoculating blood culture systems and anaerobic cultivation detects these bacteria after approximately 3-7 days when blood products have been transfused. Based on the presented data different screening strategies are discussed.
Vox Sanguinis 11/2008; 95(3):181-8. · 2.86 Impact Factor
