Staphylococcus
aureus
is a well-recognized human pathogen that exists in clinical and community
settings worldwide. Staphylococcus aureus can asymptomatically colonize
the human and is known as responsible for a wide spectrum of illnesses.
Many
typing methods have been developed to perform subspecies differentiation needed
in epidemiological studies. In this context, the aim of the present study was
to compare sequence-based typing methods, such as Multilocus sequence typing
(MLST) and spa typing, in order to assess their discriminatory power and
concordance.
This
is the subject of a new paper.
For the study, 5290 S. aureus
genomes were downloaded and used to determine MLST and spa types in silico.
To estimate discriminatory power of typing methods and concordance between them
the Simpson, adjusted Rand and adjusted Wallace indices were calculated.
GoeBURST and BURP algorithms were used for grouping MLST and spa types.
It was found that in 76.6% S.aureus
genomes the spa and MLST types were determined. Discriminatory power of spa
typing was higher (89.4%) than MLST typing (80.5%). The overall agreement
between spa typing and MLST at a type level was 39.2%. This has been proved
with directional index of partition relation (adjusted Wallace) indicating no
more 60% congruence.
Concordance
between spa and MLST typing data were not so high at a type level because of
difference in their discriminatory power. At the same time, level of agreement
between MLST and spa clonal complexes reached 89.4%. Snp correction of MLST
clonal complexes excluding MLST types with 3 and more bases distance from clonal
complexes have led to 97.2% concordance. This high concordance was observed
regardless of the place and time when Staphylococcus aureus was
isolated.
The
reference is:
Babenko, D., Omarkulov, B., Azizov, I., Sandle, T., Moraru, D. and
Chesca, A. (2016) Evaluation of sequence based typing methods (SPA and MSLT)
for clonal characterization of Staphylococcus
aureus, Acta Medica Mediterranea, 32: 1851-1856
Posted by Dr. Tim Sandle
