A new approach to imaging and rapid microbiome identification in prostate cancer patients
PD-0407
Abstract
A new approach to imaging and rapid microbiome identification in prostate cancer patients
Authors: Dorota Gabrys1, Ewelina Maślak2, Michał Złoch3, Paweł Pomastowski3, Fernanda Monedeiro3, Bogusław Buszewski2, Jolanta Mrochem-Kwarciak4, Katarzyna Bojarska4, Wioletta Miśta1
1Maria Sklodowska-Curie National Research Institute of Oncology, Radiotherapy Department, Gliwice, Poland; 2Nicolaus Copernicus University, Centre for Modern Interdisciplinary Technologies and Department of Environmental Chemistry and Bioanalytics, Faculty of Chemistry, Toruń, Poland; 3Nicolaus Copernicus University, Centre for Modern Interdisciplinary Technologies, Toruń, Poland; 4Maria Sklodowska-Curie National Research Institute of Oncology, Analaytical and Clinical Biochemistry Department, Gliwice, Poland
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Purpose or Objective
Little is known about the
impact of urinary microflora and its effects on side effect after radiotherapy
(RT). Until recently, any growth of bacteria grown from urine was considered
invasive. A new look at the issue of the composition and significance of the
urinary microbiome may bring the use of the mass spectrometry identification
method MALDI. This study aims to use the MALDI technique to identify the microbiome of
urine samples collected from pts treated with radiotherapy for prostate cancer.
Material and Methods
We included 52 pts treated
for prostate cancer irradiated with radical intent. Blood and urine samples
were collected before the gold marker implantation, on the day of beginning RT,
last day of RT, 1 month after RT. It is recommended to collect urine from the midstream,
but not always pts do it correctly despite being instructed. Therefore, we
decided to collect samples from first-void
and midstream in 12 pts for MALDI, from remaining pts we collect two
samples from midstream-void for MALDI and biochemical analysis.
Results
Microorganisms were present in 145/186 urine samples. Using three different
culture media the best microbial growth was observed on TSA (universal medium)
and CLED (differential medium for urine specimens) – the largest number of
isolates was obtained. We found 33 different species –
3 G(-) and 30 G(+). The most frequently isolated strains were: Staphylococcus
haemolyticus (19%), Staphylococcus epidermidis (18%), Staphylococcus
hominis (16%), Enterococcus faecalis (13%), and Micrococcus
luteus (10%).
When comparing the type of urine samples, bacteria were more common in
the samples from the first-void urine than from the midstream one. The absence
of bacteria was found in 12.2% of samples from the first-void urine and 24.7%
from the midstream. Overall, the ratio of the number of detected species per
number of samples corresponding to the first and middle stream were 1.80 and
1.71%, respectively. The differences in the total incidence of species between
streams did not present to be significant (p=0.85), but the number of bacterial
species in the initial stream was generally greater.
The amount of
bacterial species found in urine depended on the treatment. Before gold
fiducial implantation the total number of detected bacterial species was
significantly higher in comparison to the end of radiotherapy (p=0.038) indicating that the
administered therapy results in depleting the local microbiome (Fig. 1). One month
after radiotherapy an increase in the number of isolated bacteria was observed.
The number of bacterial species in urine did not correlate with the blood parameters.
The presence of leukocytes (p=0.013) and proteins (p=0.004) in urine were
related to a greater variety of bacteria found in urine specimens. 
Conclusion
We obtained a similar spectrum of bacteria from
the initial and middle urine streams. We also showed that there is a change in
bacteria species is affected by the treatment of prostate cancer patients. NCN 2020/39/B/NZ7/02733