Medical Trade International · Βοηθός προϊόντωνAnalytical and clinical performance report ADMED
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Performance Report 12/2023: ProbeAX Evolution/SpinAX
Analytical and clinical performance report:
ProbeAX Evolution tubes and
SpinAX device for homogenization
of tissue samples
Investigating laboratory:
Département ADMED Microbiologie
Dr. Antony Croxatto, director of microbiology department
Boucle de Cydalise 16
2300 La Chaux-de-Fonds
Table of contents
Introduction 2
Ethics and Anonymization 3
Methodology 3
Sample types 3
Sample preparation 3
Gram-staining and reading 5
Analysis 5
Results 6
Gram-staining 6
Solid and liquid culture 6
Conclusion 11
Σελίδα 2
Performance Report 12/2023: ProbeAX Evolution/SpinAX
Introduction
Osteoarticular infections require accurate microbiological The ProbeAX Evolution is a single-use sampling tube
diagnostics with careful approaches for sampling, pre- containing 5 ml 0.85% NaCl. Inside the tube is a ceramic
analytical processing and diagnostic analysis. To increase block with a rough surface and an aluminum grater on the
the diagnostic accuracy, pre-processing steps such as inside of the tube-lid. The tube containing the sample is
homogenization or grinding of tissue samples are imple- turned on its head and put into the SpinAX instrument.
mented. Different homogenization instruments are on the The instrument rotates at high speed (2200 rpm) in an
market today, for example Ultra-TurrAX® Tube Drive (IKA, oscillating motion, thus creating a grinding motion that
Germany) and the associated ProbeAX tubes (Axon Lab, grates the sample in between the ceramic block and the
Switzerland) or the gentleMACS™ Tissue Dissociator (Mil- metal-grater. In the grating, tissue is broken down, biofilm
tenyi Biotec, Germany). is taken apart and bacteria or fungi are released into the
physiological solution. An aliquot of this solution contai-
Axon Lab has developed a new homogenization instru- ning the released microorganisms can then subsequent-
ment (SpinAX, Ref. AL0500) in conjunction with a new ly be used for cultivation on agar plates, for enrichment
sampling and processing tube (ProbeAX Evolution, Ref. broth or for molecular diagnosis of pathogenic organisms.
AL0510). The objective of this study is to demonstrate effective-
ness of bacterial/fungal release from tissue samples
using the SpinAX/ProbeAX Evolution homogenization sys-
tem in comparison with Ultra-TurrAX/ProbeAX system as
a reference method, which is currently used in our lab
routine (Figure 1).
Figure 1. Left: SpinAX instrument with ProbeAX Evolution tube. Right: Ultra-TurrAX instrument with ProbeAX tube.
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Σελίδα 3
Performance Report 12/2023: ProbeAX Evolution/SpinAX
Ethics and Anonymization Methodology
No approval from the board of ethics is needed for this Sample types:
study, granted an effective anonymization of the patient 1. Soft tissue (fibrous, connective tissue, wound epithe-
sample. lium, etc.)
2. Medium to hard tissue (tendon, cartilage, bone)
For efficiency of the analytical procedure, the biological
material for the research project is used at the same time If the sample is a mix of different tissue types, it should
as it is used for the routine diagnostic (one aliquot in rou- be categorized into the «harder» category.
tine, one aliquot for research). The results for the two me-
thods then need to be compared. At the stage of inocula- Samples preparation
tion of the sample onto agar plates and broth, the sample · Biopsy samples are dissected with surgical blade under
needs to be entirely anonymized with a random number laminar flow.
(not linked to patient number). The information to be reta- · Separate samples are splitted in two parts: one part for
ined are: type of sample (bone, cartilage, tissue, etc.), link Ultra-TurrAX/ProbeAX homogenization with metal beads.
to other duplicate samples from the same patient. Time The other part for SpinAX/ProbeAX Evolution homogeni-
between arrival of sample in the laboratory and recording zation with steel rasp (see Figure 2).
of result is <1 day. The date of the analysis will not be re- · The samples are placed into an Ultra-TurrAX and SpinAX
corded. With this anonymization step, the patient should tube, respectively, both containing 5 ml sterile 0.85%
not be deduced anymore. NaCl.
· The Ultra-TurrAX tube is homogenized with the Ultra-
It is the responsibility of the technician, at the time of log- TurrAX® Tube Drive (Ref. 0003646000), according to the
ging the result, to anonymize and give a random number recommendation of the manufacturer of the device for 1
to each sample. min. at speed level 6.
· The SpinAX tube (Ref. AL0510) is put into SpinAX (Ref.
AL0500) and homogenized for 1 min. at 2200 rpm.
· From the homogenized solution, subsamples are taken
to inoculate the following solid (4 quadrants methods)
and liquid growth media – described in Table 1.
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Σελίδα 3
and liquid growth media – described in Table 1.
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Σελίδα 4
Performance Report 12/2023: ProbeAX Evolution/SpinAX
Figure 2 Tissue sample
Ultra-TurrAX SpinAX
Cultivation for Cultivation for study Cultivation for study
laboratory routine «reference test» «performance evaluation»
Recording of results
Table 1. Solid and liquid growth media, atmosphere, temperature and incubation times
Media types Atmosphere T° Incubation times
Blood agar (GS) 5% CO2 35-37°C 24/48 h
Chocolate agar (CHOC) 5% CO2 35-37°C 24/48 h
Chromagar (ORI) ambient atmosphere 35-37°C 24/48 h
Schaedler agar (SCH) anaerobiosis (Scholzen) 35-37°C 48 h
Thioglycolate (THIO) ambient atmosphere 35-37°C 5 d/14 d
· In addition a smear will be prepared for Gram-staining. Table 2. Categorization of semi-quantification results from
· After inoculation of the agar plates and broth, a liquid 0 to 4 according to microbial growth observed in the different
aliquot (500-1000 µl) from Ultra-TurrAX and SpinAX tubes inoculated quadrants.
will be frozen for long-term storage. Growth Semi-Quantification
· Each agar plate will be incubated at 35-37°C, and care- 4th quadrant 4
fully inspected at times T1 (18-24 hours), T2 (48 hours). 3rd quandrant 3
· The liquid media is incubated at 35-37°C and inspected
2nd quadrant 2
for growth after T3 (5 days) and T4 (14 days).
1 quadrant/Few CFUs
st
1
· Growth/no-growth will be noted for each sample and
agar type. When growth is observed, a semi-quantifica- no growth 0
tion will be reported (1+ to 4+) and an identification will
be done by MALDI-TOF for each microbial morphology.
· Images are taken of each plate with bacterial growth.
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Σελίδα 5
Performance Report 12/2023: ProbeAX Evolution/SpinAX
Gram staining and reading Analysis
· Slides will be Gram-stained with the Aerospray® Gram- · The results will be recorded in a database.
slide stainer, ELITech France. · The SpinAX results will be compared to the Ultra-TurrAX
· The slides will be read by microscopy as described in results. Similar and discordant results will be measured
our laboratory SOP. The following biological material will between the 2 different methods. A detailed description
be reported (Leucocytes, Erythrocytes, Epithelial cells, of the discordances will be presented.
Gram positive and Gram negative bacteria).
Table 3. Categorization of results according to quantity of
cells or bacteria per microscopy field. Cells: epithelial cells,
erythrocytes or leucocytes. Bacteria: Gram positive or Gram
negative bacteria.
Cells/microscopy Bacteria/microscopy Quantification
field (100x) field (100x)
>25 >25 4
6-25 6-25 3
2-5 2-5 2
1 1 1
no cells no cells 0
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Σελίδα 6
Performance Report 12/2023: ProbeAX Evolution/SpinAX
Results
Gram-staining
The global results are presented in Table 4.
Table 4. Comparison of cell count after Gram staining. Percent of total (absolute numbers).
Gram Cell count with Cell count with the Cell count with the
staining both methods SpinAX only Ultra-TurrAX only
GPC 52% (13/25) 36% (9/25) 11% (3/25)
GNB 45% (5/11) 45% (5/11) 9% (1/11)
Erythrocytes 85% (73/86) 12% (10/86) 3% (3/86)
Leucocytes 74% (61/82) 18% (15/82) 7% (6/82)
Epithelial cells 33% (2/6) 50% (3/6) 17% (1/6)
Total 73% (154/210) 20% (42/210) 7% (14/210)
GPC: Gram positive Cocci, GNB: Gram negative bacilli
Microorganisms and cells not seen by microscopy with Ultra-TurrAX or the SpinAX but observed with the other method
are listed in Table 5.
Table 5. Microorganisms and cells not observed by microscopy (Gram staining with the SpinAX or the Ultra-TurrAX).
SpinAX (S/MH) Ultra-TurrAX (S/MH) Total (S/MH)
GPC 1 (0/1) 5 (3/2) 6 (3/3)
GNB 0 (0/0) 2 (1/1) 2 (1/1)
Erythrocytes 0 (0/0) 0 (0/0) 0 (0/0)
Leucocytes 0 (0/0) 2 (2/0) 2 (2/0)
Epithelial cells 0 (0/0) 1 (1/0) 1 (1/0)
Total 1 (0/1) 10 (7/3) 11 (7/4)
GPC: Gram positive Cocci, GNB: Gram negative bacilli, S: Soft biopsy, MH: Medium to hard biopsy
Solid and liquid culture
A total of 96 clinical samples biopsies, 31 medium to hard and 65 soft, from 58 patients have been analyzed by culture
following Utra-TurrAX and SpinAX homogenization (Table 6).
Table 6. Number of specimen and patients included in the study
Biopsy
Soft Medium to hard Total
Patients 34 24 58
Samples 65 31 96
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Performance Report 12/2023: ProbeAX Evolution/SpinAX
False negative samples
Three false negative samples were observed with Ultra-
TurrAX (Table 7).
· Two specimen of soft tissue from one patient exhibited
a positive result with the SpinAX with a few colonies of
Staphylococcus aureus and a false negative result for the
Ultra-TurrAX. However, the Staphylococcus aureus strain
was recovered from the Thioglycolate enrichment broth
in one of the two specimen of the patient.
· A single specimen from one patient exhibited a positive
result with the SpinAX with a few colonies of Staphylo-
coccus aureus and a false negative result for the Ultra-
TurrAX. No Staphylococcus aureus strain was recovered
from the Thioglycolate enrichment broth in this speci-
men for the Ultra-TurrAX.
Global growth
Out of the 94 clinical isolates, 6 (6.4%) exhibited a signifi-
cant better growth (categorization difference >1) follow-
ing Ultra-TurrAX homogenization of 4 different specimen
(3 medium to hard and 1 soft tissues) whereas 4 (4.3%)
showed a better growth following SpinAX homogeniza-
tion of 4 different specimen (2 medium to hard and 2 soft
tissues). Thus, 84 (89.4%) clinical isolates showed a si-
milar growth (growth categorization ≤1) following Ultra-
TurrAX or SpinAX homogenization (Table 7).
Clinical isolates
Out of the 42 positive samples, 94 bacterial isolates
belonging to 41 bacterial species were recovered on a
least one of the four inoculated agar media (Table 7 and
Table 8).
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Σελίδα 11
Performance Report 12/2023: ProbeAX Evolution/SpinAX
Conclusion
The SpinAX device in conjunction with the ProbeAX Evolu- et al, PLOS One, 2017, https://doi.org/10.1371/journal.
tion tube has an homogenization efficiency equal to Ultra- pone.0187263). Indeed, in this study, 39.5% of major
TurrAX device in conjunction with the ProbeAX tubes with discrepancies of the Gram staining preparation and rea-
89.4% of the specimen showing similar bacterial growth. ding were observed from the same sample processed
twice by the diagnostic laboratory.
Most of the discrepancies are very likely explained by
biological variation of the microbial load that is not uni- Overall, the SpinAX homogenization is thus providing an
formly distributed in a tissue sample. Indeed, as the tis- overall similar performance than Ultra-TurrAX with a pos-
sue samples were split into 2 parts for this performance sible better homogenization and/or ultra-structure pre-
evaluation, discrepancies can be expected with different servation for Gram staining microscopy. We have also
growth recovery or absence of growth following one of observed macroscopically a better homogenization with
the 2 methods when there is a weak bacterial load that the SpinAX than Ultra-TurrAX with the absence of aggre-
is not systematically recovered by culture (Model of Pois- gates after homogenization. The pipetting of the SpinAX
son, low probability). In addition, discrepancies with a supernatant was thus also easier to perform. Finally, the
high bacterial load could be expected when the microor- reduced noise produced during the SpinAX grinding and
ganisms are not equally distributed in the specimen. Inde- homogenizing compared to Ultra-TurrAX was really appre-
ed, the most significant differences (discrepancies with ciated by the laboratory staff.
semi-quantitative differences >1) were mainly observed
with medium to hard tissues that are difficult to process Study sponsor:
and to split into two equal parts (Table 9 and 10).
Axon Lab AG
The SpinAX seems to allow a better detection of micro- Täfernstrasse 15
organisms and host cells by Gram staining microscopy 5405 Baden-Dättwil
(Table 4 and 5). Ultra-TurrAX microorganisms or host cells
were not detected in 10 samples with: GPC not obser-
ved in 5 samples, GNB in 2 samples, Leucocytes in 2
samples and Epithelial cells in 1 sample, whereas in only
one sample after SpinAX homogenization. However, the-
se differences of Gram staining microscopy could also
be explained by the lack of reproducibility of this analy-
sis as showed in an Internal quality assurance investiga-
tion performed in diagnostic microbiology (see Scherz
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