Stefan Tyski

Dr. Stefan Tyski

Department of Pharmaceutical Microbiology, Medical University of Warsaw, Center for Preclinical Research and Technology, Banacha 1 b Str., 02-097 Warsaw, Poland; Department of Antibiotics and Microbiology, National Drug Institute, Chelmska 30/34 Str., 00-725 Warsaw, Poland.
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Research Focus & Metrics

Academic Career Length

50Years (1977-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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27 April 2022 in Archives of Microbiology
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Journal Article
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AZAnna Zawistowska-Rojek
Anna Zawistowska-Rojek
AKAnita Kośmider
Anita Kośmider
Karolina StępieńKarolina Stępień
Karolina Stępień
STStefan Tyski
Stefan Tyski
The adhesion and aggregation are characteristic attributes of probiotic strains belonging to Lactobacillaceae genus. Due to these properties the host organisms can avoid colonisation of the intestinal tract by enteropathogenic bacteria. The presented research includes a comparison of the properties of various strains belonging to different Lactobacillaceae species and isolated from different sources The aim of this study was to investigate the ability of Lactocaseibacillus rhamnosus, Lactiplantibacillus plantarum, and Lactobacillus strains (L. acidophilus, L. gasseri, L. ultunensis) from probiotic products and clinical specimens to direct and competitive adherence to Caco-2 and HT-29 cell lines. Furthermore, the ability of lactobacilli and enteropathogenic bacteria, E. coli, E. faecalis, and S. Typhimurium, to auto- and co-aggregation was also investigated.The results showed that all tested strains adhered to Caco-2 and HT-29 cell lines. Though, the factor of adhesion depended on the species and origin of the strain. L. rhamnosus strains showed a lowest degree of adherence as compared to L. plantarum and Lactobacillus sp. strains. On the other side both, L. rhamnosus and L. acidophilus strains reduced the pathogenic bacteria in competition adherence test most effectively. All tested lactobacilli strains were characterised by auto- and co-aggregation abilities, to various degrees. The properties of Lactobacillaceae strains analysed in this study, like adhesion abilities, competitive adherence, auto- and co-aggregation, may affect the prevention of colonisation and elimination of pathogenic bacteria in gastrointestinal tract.

1 January 2018 in Polish Journal of Microbiology
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AZAnna Zawistowska-Rojek
Anna Zawistowska-Rojek
STStefan Tyski
Stefan Tyski
Probiotic bacteria have been used as a health-promoting factor for a very long time. Nowadays, products containing probiotic bacteria are becoming more and more popular on the market. The term probiotics refers to the products belonging to the following groups: probiotic drugs (medicinal products – live biotherapeutic products for human use), medical devices, probiotic foods (e.g. foods, food ingredients, dietary supplements or food for special medical purposes), directly fed microorganisms (for animal use) and designer probiotics (genetically modified probiotics). Safety assessment of bacterial strains used as probiotics should be carefully studied. Even though probiotic bacteria have the generally recognized as safe (GRAS status), there are several reports about side effects triggered by the presence of these organisms. Microorganisms used as probiotics may cause systemic infections, stimulate the immune system, disturb metabolism and participate in horizontal gene transfer.

1 February 2013 in Bioorganic & Medicinal Chemistry
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Journal Article
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KMKatrzyna Michalska
Katrzyna Michalska
IKIzabela Karpiuk
Izabela Karpiuk
MKMarek Krol
Marek Krol
STStefan Tyski
Stefan Tyski

1 November 2017 in Therapeutics and Clinical Risk Management
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RPRafal Pokrowiecki
Rafal Pokrowiecki
AMAgnieszka Beata Mielczarek
Agnieszka Beata Mielczarek
TZTomasz Zaręba
Tomasz Zaręba
STStefan Tyski
Stefan Tyski
Oral microbiome and peri-implant diseases: where are we now? Rafal Pokrowiecki,1 Agnieszka Mielczarek,2 Tomasz Zareba,3 Stefan Tyski3,4 1Department of Head and Neck Surgery-Maxillofacial Surgery, Otolaryngology and Ophthalmology, Prof Stanislaw Popowski Voivoid Children Hospital, Olsztyn, 2Department of Conservative Dentistry, Medical University of Warsaw, 3Department of Antibiotics and Microbiology, National Medicines Institute, 4Department of Pharmaceutical Microbiology, Medical University of Warsaw, Warsaw, Poland Peri-implant infective diseases (PIIDs) in oral implantology are commonly known as peri-implant mucositis (PIM) and periimplantitis (PI). While PIM is restricted to the peri-implant mucosa and is reversible, PI also affects implant-supporting bone and, therefore, is very difficult to eradicate. PIIDs in clinical outcome may resemble gingivitis and periodontitis, as they share similar risk factors. However, recent study in the field of proteomics and other molecular studies indicate that PIIDs exhibit significant differences when compared to periodontal diseases. This review aims to elucidate the current knowledge of PIIDs, their etiopathology and diversified microbiology as well as the role of molecular studies, which may be a key to personalized diagnostic and treatment protocols of peri-implant infections in the near future. Keywords: dental plaque, infection, titanium, microbiome, periimplantitis

28 June 2017 in PLOS ONE
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ALAgnieszka Laudy
Agnieszka Laudy
PRPatrycja Róg
Patrycja Róg
KSKatarzyna Smolińska-Król
Katarzyna Smolińska-Król
MĆMilena Ćmiel
Milena Ćmiel
ASAlicja Słoczyńska
Alicja Słoczyńska
STStefan Tyski
Stefan Tyski
Knowledge of the prevalence of ESBL enzymes among P. aeruginosa strains compared to the Enterobacteraiceae family is limited. The phenotypic tests recommended by EUCAST for the detection of ESBL-producing Enterobacteriaceae are not always suited for P. aeruginosa strains. This is mainly due to the presence of other families of ESBLs in P. aeruginosa isolates more often than in Enterobacteriaceae, production of natural AmpC cephalosporinase and its overexpression, and co-production of metallo-β-lactamases. The aim of this study was to determine the occurrence of ESBLs in P. aeruginosa isolated from patients from hospitals in Warsaw, to evaluate the ESBL production of these isolates using currently available phenotypic tests, their modifications, multiplex PCR and molecular typing of ESBL-positive isolates by PFGE. Clinical isolates of P. aeruginosa were collected in 2000-2014 from four Warsaw hospitals. Based on the data obtained in this study, we suggest using three DDST methods with inhibitors, such as clavulanic acid, sulbactam and imipenem, to detect ESBL-producing P. aeruginosa strains. Depending on the appearance of the plates, we suggest a reduction in the distance between discs with antibiotics to 15 mm and the addition of boronic acid at 0.4 mg per disc. The analysed isolates carried genes encoding ESBL from the families VEB (69 isolates with VEB-9), GES (6 with GES-1, 1 GES-5, 5 GES-13 and 2 with GES-15), OXA-2 (12 with OXA-15, 1 OXA-141, 1 OXA-210, 1 OXA-543 and 1 with OXA-544) and OXA-10 (5 isolates with OXA-74 and one with OXA-142). The most important result of this study was the discovery of three new genes, blaGES-15, blaOXA-141 and blaOXA-142; their nucleotide sequences have been submitted to the NCBI GenBank. It is also very important to note that this is the first report on the epidemiological problem of VEB-9-producing bacterial strains, not only in Poland but also worldwide.

1 June 2002 in Journal of Pharmaceutical and Biomedical Analysis
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Journal Article
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GPGenowefa Pajchel
Genowefa Pajchel
KPKrzysztof Pawłowski
Krzysztof Pawłowski
STStefan Tyski
Stefan Tyski