1. Genetic diversity of Campylobacter concisus isolates from Slovenian patients with infectious diarrhoeaRomina Kofol, Mateja Pirš, Tadeja Kotar, Tatjana Lejko-Zupanc, Andraž Celar Šturm, Andreja Kukec, Tadeja Matos, Tina Triglav, 2025, original scientific article Abstract: Campylobacter concisus is recognized as a potential pathogen in gastrointestinal diseases, particularly in patients with chronic intestinal diseases. This study investigates the genomic characteristics, phylogenetic distribution, virulence factors, resistance genes and presence of plasmids in C. concisus isolates from Slovenian patients with community-acquired infectious diarrhoea. Prospectively collected isolates were analysed using whole-genome sequencing (WGS). WGS analysis revealed substantial genetic diversity among isolates, with distinct differences observed between two genomospecies (GS1, GS2). GS1 isolates had smaller genomes, lower GC content, and fewer coding regions than GS2 isolates. Multilocus sequence typing confirmed a high degree of genetic diversity, with most isolates belonging to novel sequence types. Plasmids, including pSma1 and pICON, were more prevalent in GS2 isolates. The virulence factors Zot and Exo9 toxins were detected in both genomospecies, with Zot predominantly found in GS1 and Exo9 in GS2. The T6 secretion system was prevalent in both groups, whereas the T4SS was less frequently observed. The combination of the T6SS, plasmids, and toxins suggests a complex mechanism of pathogenicity. This study highlights the high genetic diversity of C. concisus and provides new insights into its genomic features and virulence factors. The presence of plasmids and secretion systems, particularly the T6SS, underscores the potential of C. concisus for adaptation and pathogenicity.
Keywords: Campylobacter concisus, WGS, virulence factors
Published in DiRROS: 16.04.2026; Views: 302; Downloads: 227
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2. Genomic virulence markers are associated with severe outcomes in patients with Pseudomonas aeruginosa bloodstream infectionJohn Karlsson Valik, Christian G Giske, Badrul Hasan, Mónica Gozalo-Margüello, Luis Martínez-Martínez, Manica Müller-Premru, Žiga Martinčič, Bojana Beović, Sofia Maraki, 2024, original scientific article Abstract: Background: Pseudomonas aeruginosa (PA) bloodstream infection (BSI) is a common healthcare-associated complication linked to antimicrobial resistance and high mortality. Ongoing clinical trials are exploring novel anti-virulence agents, yet studies on how bacterial virulence affects PA infection outcomes is conflicting and data from real-world clinical populations is limited. Methods: We studied a multicentre cohort of 773 adult patients with PA BSI consecutively collected during 7-years from sites in Europe and Australia. Comprehensive clinical data and whole-genome sequencing of all bacterial strains were obtained. Results: Based on the virulence genotype, we identify several virulence clusters, each showing varying proportions of multidrug-resistant phenotypes. Genes tied to biofilm synthesis and epidemic clones ST175 and ST235 are associated with mortality, while the type III secretion system is associated with septic shock. Adding genomic biomarkers to machine learning models based on clinical data indicates improved prediction of severe outcomes in PA BSI patients. Conclusions: These findings suggest that virulence markers provide prognostic information with potential applications in guiding adjuvant sepsis treatments.
Keywords: Pseudomonas aeruginosa, bloodstream infection, virulence
Published in DiRROS: 27.02.2026; Views: 603; Downloads: 335
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3. Varietal susceptibility of olive to Pseudomonas savastanoi pv. savastanoi and the antibacterial potential of plant-based agentsLaura Košćak, Janja Lamovšek, Marina Lukić, Tvrtko Karlo Kovačević, Edyta Đermić, Smiljana Goreta Ban, Nikola Major, Sara Godena, 2024, original scientific article Keywords: olive knot disease, olive genotype susceptibility, phenols, plant-based antibacterial agents, strain virulence
Published in DiRROS: 03.02.2026; Views: 577; Downloads: 376
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4. Loop-mediated isothermal amplification : rapid molecular detection of virulence genes associated with avian pathogenic Escherichia coli in poultryPolona Kogovšek, Jerneja Ambrožič, Alenka Dovč, Tanja Dreo, Hristo Hristov, Uroš Krapež, Maja Ravnikar, Brigita Slavec, Marjetka Lotrič, Jana Žel, Olga Zorman-Rojs, 2018, original scientific article Abstract: Infections with pathogenic Escherichia colican lead to different animal- and human-associated diseases. E. coliinfections are common in intensive poultry farming, and important economic losses can be expected during infections with avian pathogenic E. coli(APEC) strains followed by colibacillosis. Loop-mediated isothermal amplification (LAMP) assays were developed for rapid detection of 3 APEC-associated virulence genes: sitA, traT, and ompT. All 3 LAMP assays are shown to be specific, repeatable, and reproducible. High sensitivities of the assays are shown, where as few as 1,000 bacterial cells/mL can be detected in different matrices. On-site applicability of this LAMP method is demonstrated through testing of different sample types, from animal swabs and tissues, and from environmental samples collected from 6 commercial poultry farms. All 3 virulence genes were detected at high rates (above 85%) in samples from layer and broiler chickens with clinical signs and, interestingly, high prevalence of those genes was detected also in samples collected from clinically healthy broiler flock (above 75%) while lower prevalence was observed in remaining 3 clinically healthy chicken flocks (less than 75%). Importantly, these virulence genes were detected in almost all of the air samples from 11 randomly selected poultry houses, indicating air as an important route of E. colispread. Three LAMP assays that target APEC-associated virulence genes are shown to be sensitive and robust and are therefore applicable for rapid on-site testing of various sample types, from animal swabs to air. This on-site LAMP testing protocol offers rapid diagnostics, with results obtained in <35 min, and it can be applied to other important microorganisms to allow the required prompt measures to be taken.
Keywords: APEC virulence genes, isothermal amplification LAMP, on-site detection, colibacillosis
Published in DiRROS: 24.07.2024; Views: 3364; Downloads: 856
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5. Stress-tolerant yeasts : opportunistic pathogenicity versus biocontrol potentialJanja Zajc Žunič, Cene Gostinčar, Anja Černoša, Nina Gunde-Cimerman, 2019, original scientific article Abstract: Stress-tolerant fungi that can thrive under various environmental extremes are highly desirable for their application to biological control, as an alternative to chemicals for pest management. However, in fungi, the mechanisms of stress tolerance might also have roles in mammal opportunism. We tested five species with high biocontrol potential in agriculture (Aureobasidium pullulans, Debayomyces hansenii, Meyerozyma guilliermondii, Metschnikowia fructicola, Rhodotorula mucilaginosa) and two species recognized as emerging opportunistic human pathogens (Exophiala dermatitidis, Aureobasidium melanogenum) for growth under oligotrophic conditions and at 37 °C, and for tolerance to oxidative stress, formation of biofilms, production of hydrolytic enzymes and siderophores, and use of hydrocarbons as sole carbon source. The results show large overlap between traits desirable for biocontrol and traits linked to opportunism (growth under oligotrophic conditions, production of siderophores, high oxidative stress tolerance, and specific enzyme activities). Based on existing knowledge and these data, we suggest that oligotrophism and thermotolerance together with siderophore production at 37 °C, urease activity, melanization, and biofilm production are the main traits that increase the potential for fungi to cause opportunistic infections in mammals. These traits should be carefully considered when assessing safety of potential biocontrol agents.
Keywords: opportunistic pathogen, biocontrol agent, virulence, stress tolerance, secretome, CAZy, protease, thermotolerance, oligotrophism, melanin, siderophore, biofilm
Published in DiRROS: 23.07.2024; Views: 1413; Downloads: 925
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