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Clinical and microbiological characteristics of community strains of Staphylococcus lugdunensis
PETŘÍKOVÁ, Barbora
The bachelor thesis is focused on characterization of coagulase-negative staphylococcus. Staphylococcus lugdunenis is considered to be an opportunist pathogen, which is able to cause an infection in healthy individuals, as only one of few existing CNS. The aim of this thesis is to sum up actual knowledge about a clinical importace, basic characteristic and possibilities of laboratory diagnostics of the species Staphylococcus lugdunensis. The initial chapter of this bachelor thesis is dedicated to a description of staphylococcus and its distribition to a positive and a negative clumbing factor. In the thesis is described its morphology and further the detailed characteristic of Staphylococcus lugdunensis, its microbiological characteristic and identification possibilities with assistance of different biochemical tests Methodical part of the thesis was carried out in the laboratory Stafila Ltd. I was watching the finding of Staphylococcus lugdunensis in this laboratory during one year (January December 2016). In this part is described a differentiation of staphylococcus to staphylococcus clumbing factor positive and staphylococcus clumbing factor negative. Then follows an identification of species which is focused on the species of Staphylococcus lugdunensis. The species identification was carried out with a commercial test STAPHYtest24. Then I concentrated on description of all tests which are used in this laboratory for an exact identification S. lugdunensis, e,g. HYA test, PYR test and others. For species which were identified as Staphylococcus lugdunensis was carried out a test for susceptibility to antibiotics using a method of disc diffusion sensitivity. Further is a practical part of this thesis dedicated to comparison of species Staphylococcus aureus and Staphylococcus lugdunensis. The comparison of these two species confirmed, as expected, that a presence of Staphylococcus aureus is much higher than S. lugdunensis, but infections caused by S. lugdunensis are from clinical point of view very similar to them where was proved a pathogen S. aureus.
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Current possibilities of laboratory diagnosis of staphylococcal infections
CHRTOVÁ, Lucie
Laboratory diagnostics of Staphylococccal infections is based on direct evidence, like microscopy and cultivation, eventually on molecular genetics methods. The objective of this thesis is the presentation of nowadays possibilities in laboratory diagnostics of coagulase - negative staphylococcal infections and comparsion of two methods of identification used in the routine laboratory practice. First part of the thesis presents the genus Staphylococcus and the difference between it and the genuses Micrococcus and Peptococcus. The following part of this thesis shows the distribution of genus Staphylococcus in two main groups (Staphylococcus coagulase - positive and coagulase - negative), based on the ability to coagulate plasma. The description of these two main groups contains their morphological and cultivation features, antigen structure, virulence factors, pathogenesis and laboratory diagnostics. In the methodical part the pre-analytic and analytic phase is mentioned. The focus of the pre-analytic part the general priciples of collection and transport for microbiological analysis and the collection of material itself. The methodical part was performed in the České Budějovice Hospital - Laboratory of Medical Microbiology - Department of Bacteriology. This part of the thesis presents the differentiation of staphylococci by latex agglutination (PROLEX TM STAPH LATEX KIT) and then specific identification of 52 strains of coagulase-negative staphylococci isolated from central venous catheters , hemocultures and other clinical important materials is following. The specific identification of all the 52 strains of coagulase-negative staphylococci was performed by biochemical identification by STAPHYtest 16 (ErbaLachema) and parallel by mass spectrometry MALDI-TOF (system VITEK MSTM). The correct identification reached 96,2 % by the method of mass spectrometry MALDI-TOF and 67,3 % by biochemical identification STAPHYtest 16. The most frequent species isolated was Staphylococcus epidermidis (64 %), then Staphylococcus hominis ssp. hominis (10 %), Staphylococcus capitis (6 %), Staphylococcus warneri (6 %), Staphylococcus lugdunensis (4 %), Staphylococcus haemolyticus (4 %), Staphylococcus hominis (4 %), Staphylococcus caprae (2 %). The comparsion of both named methods shows the mass spectrometry more reliable, faster and simpler method, and more suitable for routine laboratory work.
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