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Dive into the research topics where Darja Keše is active.

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Featured researches published by Darja Keše.


Eurosurveillance | 2015

Prevalence, genotyping and macrolide resistance of Mycoplasma pneumoniae among isolates of patients with respiratory tract infections, Central Slovenia, 2006 to 2014

Rok Kogoj; Tatjana Mrvic; Marina Praprotnik; Darja Keše

In this retrospective study we employed real-time polymerase chain reaction (PCR) to analyse the occurrence of Mycoplasma pneumoniae among upper and lower respiratory tract infections (RTI) in the Central Region of Slovenia between January 2006 and December 2014. We also used a culture and pyrosequencing approach to genotype strains and infer their potential macrolide resistance. Of a total 9,431 tested samples from in- and out-patient with RTI, 1,255 (13%) were found to be positive by M. pneumoniae PCR. The proportion of positive samples was 19% (947/5,092)among children (≤16 years-old) and 7% (308/4,339) among adults (>16 years-old). Overall, among those PCR tested, the highest proportions of M. pneumonia infections during the study period were observed in 2010 and 2014. In these two years, 18% (218/1,237) and 25% (721/2,844) of samples were positive respectively,indicating epidemic periods. From the 1,255 M. pneumoniae PCR-positive samples, 783 (614 from paediatric and 169 from adult patients) were successfully cultured. Of these, 40% (312/783) were constituted of strains belonging to the P1 type II genomic group, while 60% (469/783) contained strains of the P1 type I group. Two isolates comprised both P1 type Iand II strains. Results of a genotype analysis by year,showed that the dominant M. pneumoniae P1 type during the 2010 epidemic was P1 type II (82% of isolates;81/99), which was replaced by P1 type I in the 2014 epidemic (75%; 384/510). This observation could indicate that the two epidemics may have been driven by a type shift phenomenon, although both types remained present in the studied population during the assessed period of time. Only 1% of strains (7/783) were found to harbour an A2063G mutation in the 23S rRNA gene,which confers macrolide resistance, suggesting that the occurrence of M. pneumoniae macrolide resistance still seems to be sporadic in our geographic area.


Scandinavian Journal of Infectious Diseases | 2012

Epidemiological investigation of a legionellosis outbreak in a Slovenian nursing home, August 2010.

Alenka Trop Skaza; Lucija Beškovnik; Alenka Storman; Darja Keše; Simona Ursic

Abstract Background: August 2010 marked the beginning of the largest outbreak of legionellosis in a Slovenian nursing home. This article presents our experiences with the outbreak investigation. Methods: In order to collect the necessary patient epidemiological data, we used individual epidemiological questionnaires. Samples were available from 15 patients and were subject to laboratory investigation. Urine and sputum samples were difficult to obtain due to the underlying diseases of the patients. Serological diagnostics constituted an important part of the epidemiological investigation. Sixty-four environmental samples were taken to identify the sources of infection. By genotyping, we assessed the affinity of the allelic profile of Legionella pneumophila serogroup 1 in environmental samples and in patient samples. Results: Legionnaires’ disease was diagnosed in 10 patients based on a combination of various tests. Legionella pneumophila serogroup 1, Legionella pneumophila serogroups 2–14, and Legionella sp., in concentrations of < 10 to 61,000 CFU/l, were isolated from 51 out of 64 environmental samples. The source of the outbreak was confirmed by genotyping the isolates from patients and the isolates from the water supply system. The 2 isolates had identical allelic profiles corresponding to that of L. pneumophila serogroup 1 allelic profile 2,3,9,10,2,1,6, designated sequence type 23 (according to the European Working Group for Legionella Infections). Conclusion: We describe a Legionella pneumophila serogroup 1 outbreak in a Slovenian nursing home. The source of infection was demonstrated using sequence-based typing. Water flow disturbances were determined as the most probable cause of Legionella growth. Overall, the risk of a Legionella outbreak is underestimated in Slovenia.


Fems Immunology and Medical Microbiology | 2011

Genotyping of Chlamydia trachomatis directly from urogenital and conjunctiva samples using an ompA gene pyrosequencing-based assay

Darja Keše; Marko Potočnik; Mojca Maticic; Rok Kogoj

The aim of the present study was to develop and validate a multitarget pyrosequencing-based protocol for basic Chlamydia trachomatis genotyping directly from clinical samples and to characterize the distribution of genotypes among Slovenian sexually active population. The newly developed combination of assays that targets the variable domains VD-I and VD-IV of the C. trachomatis ompA gene, was optimized and validated with 11 reference C. trachomatis strains and by comparison to complete ompA conventional sequencing. In addition, 183 clinical specimens which were previously diagnosed as C. trachomatis positive were evaluated by pyrosequencing. The pyrosequencing products showed a 100% match to corresponding sections of the respective conventional ompA sequences. Based on our results the most frequent genotype in urogenital samples was E (51.1%) followed by F (21.4%), G and K (6.9%), D (6.1%), H (3.8%), J (2.3%) and Ia and Ja (0.8%). In conjunctiva samples the genotype distribution was E (63.3%), D and F (13.3%), K (6.7%) and G (3.3%). Pyrosequencing thus proved itself to be a rapid method for C. trachomatis typing, which is important for better understanding the pathogenesis and epidemiology of this pathogen.


Scandinavian Journal of Infectious Diseases | 2002

Chlamydia pneumoniae Infections in Patients with Community-acquired Pneumonia in Slovenia

Darja Keše; Milan Cizman; Jozica Marin; Tatjana Avsic Zupanc

It is well known that Chlamydia pneumoniae is an important respiratory pathogen. In this study, the prevalence of specific antibodies to C. pneumoniae in hospitalized patients with community-acquired pneumonia (943 adult females, 990 adult males and 185 children) was evaluated over a period of 7 y (1993-99). Two serum samples were obtained from all of the patients: 1 on admission and the other 3 weeks later. The specimens were tested for C. pneumoniae IgG, IgM and IgA antibodies by means of a microimmunofluorescence test. Acute infection with C. pneumoniae was determined in 9.4% of females and 13.1% of males. In children and adolescent patients, the microimmunofluorescence test showed recent infection in 8.6% of cases, with the highest prevalence occurring in the 11-15 y age group. The highest prevalence of C. pneumoniae pneumonia was found in 1995 and 1999: 15.4% and 13.6% respectively. The results obtained showed that C. pneumoniae is persistently present in the population of Slovenia.


Eurosurveillance | 2016

Confirmed inguinal lymphogranuloma venereum genovar L2c in a man who had sex with men, Slovenia, 2015

Mojca Matičič; Irena Klavs; Jerneja Videčnik Zorman; Darja Vidmar Vovko; Rok Kogoj; Darja Keše

A laboratory-confirmed lymphogranuloma venereum (LGV) case in Slovenia was reported in 2015, in a human immunodeficiency virus (HIV)-negative man presenting with inguinal lymphadenopathy. He reported unprotected insertive anal intercourse with two male partners in Croatia. Variant L2c of Chlamydia trachomatis was detected in clinical samples. Although the patient was eventually cured, the recommended treatment regimen with doxycycline had to be prolonged.


Angiology | 2004

Histopathologic signs for the inflammatory role of Chlamydia pneumoniae in the high-grade atherosclerotic coronary artery wall.

Mateja Legan; Olga Vraspir-Porenta; Darja Keše; Ruda Zorc-Pleskovič; Marjeta Zorc

The aim of the study was to prove the long-lasting and continuously harmful effect of chronic Chlamydia pneumoniae (CPn) infection on vessel walls in patients with diffuse coronary artery disease (CAD). In surgically obtained endarterectomized atherosclerotic plaques grade VI-VIII (Stary classification) from 10 patients with diffuse coronary artery disease and chronic (7) or past (3) CPninfection, signs of inflammatory response of the vessel wall on infectious agents were studied. In all 10 endarterectomized plaque step serial sections, immunologic signs of vessel wall response were present (positive T- and B-lymphocytes, macrophages, and capillarogenesis). In 8 of 10 patients’ atherosclerotic plaque, unique features of active vasculitis in the neoarteriolar wall as well as arteriologenesis, were found. Seven of these 8 patients had serologically proven chronic CPninfection, and 1 had past infection. Features of vasculitis as well as arteriologenesis were absent in 2 patients who recovered from CPninfection at the time of surgery. In the endarterectomized segments of 3 randomly chosen patients in this study, the polymerase chain reaction method revealed positive DNA of CPn.Two of these patients had chronic infection, but the third had only a past CPninfection. This study provides evidence that CPninfection has continuous and a long-lasting inflammatory response in the high-grade atherosclerotic coronary artery vessel wall.


The Cardiology | 2005

Detection of Chlamydia pneumoniae DNA in the coronary arteries and bypass in three patients with diffuse coronary artery disease

Marjeta Zorc; Olga Vraspir-Porenta; Darja Keše; Danijel Petrovič; Mateja Legan

Accessible online at: www.karger.com/crd There is growing evidence of the possible pathogenetic mechanism through which Chlamydia pneumoniae (CP) could affect the atherosclerotic process [1, 2]. CP is commonly found in atherosclerotically changed human vessels, but only rarely in the nonatherosclerotic part of the vessel [3]. The reported detection rate was about 60% in atheromatous lesions versus 3% in nonatherosclerotic arterial specimens. So far, there have been no reports on the presence of CP in diffuse coronary atherosclerosis. This letter reports on the association of CP-DNA and diffuse coronary atherosclerosis in 3 patients with chronic/past infection with CP. Patient M.R., born in 1939, was reoperated in May 2000. The revascularization procedure was done in the coronary and carotid vessels. The bypass (arteria mammaria) performed in 1992 on the left circumflex coronary artery was occluded and the endarterectomy procedure was used. The patient had elevated CP antibodies that indicated chronic CP infection according to serological criteria [4]. Patient T.T., born in 1942, who had diffuse coronary artery disease for 15 years and who had an antibody response indicating chronic CP infection, had a third bypass operation on coronary arteries in January 2001 (the first operation was in 1989 and the second in 1994). Patient I.K., born in 1956, who had diffuse coronary artery disease and chronic persistent infection with CP, was surgically treated in June 1999. A coronary artery bypass graft operation with endarterectomy was performed. The tissue samples of the left anterior descending artery and their diagonal branches were examined for the presence of CP-DNA by the PCR method. Preoperatively, serum antibody levels to CP were determined from a peripheral blood sample with the standard microimmunofluorescence method utilizing CP, Chlamydia psittaci and Chlamydia trachomatis elementary bodies (MRL Diagnostics, USA) as antigens to detect specific IgG, IgM and IgA antibodies. Serological evidence of CP infection was based on the criteria published by Grayston et al. [4]. A 4-fold rise in IgG/IgA titer in paired sera or an IgM titer of 61:20 in any serum was considered as presumptive evidence of acute or recent infection with CP. Titers of IgG 61:32 and !1:512 were assumed to be due to past infection with CP. Titers with stable IgG and IgA titers 61:32 were assumed to represent chronic infection with CP. A negative result was defined as an IgG/IgA titer !1:32 and IgM titer !1:20. Serum samples were taken twice in a 4-week period and occasionally during the following months, to detect the stable titer of antibodies (the diapason of variability is shown in table 1). Table 1. Consecutive titers of CP antibodies in our patients’ sera


Protoplasma | 2015

The effect of LDL particles on the behaviour of epithelial noncancer and cancer cell lines after in vitro induced injury

Nataša Resnik; Anja Mavrič; Darja Keše; Peter Veranič; Daša Zupančič

Cell spreading capability and cell proliferation are the major processes in wound healing of injured epithelia as well as in tumour progression. The effect of low-density lipoprotein (LDL) particles as a major extracellular source of cholesterol was evaluated in the re-epithelisation assay of in vitro induced injury. We selected two noncancer cell lines with different dependence on LDL concentrations, the kidney epithelial cells (MDCK) with higher dependence and keratinocytes (HaCaT) with lower dependence on LDL, and three cancer cell lines originating from epithelial cells: A549 (alveolar), CaCo-2 (intestinal) and RT4 (urothelial). All cells were incubated in a control medium, in an LDL-enriched medium or in an LDL-deficient medium. The LDL-enriched medium stimulated cell spreading of MDCK cells which, together with increased proliferation of these cells, resulted in an enhanced re-epithelisation of in vitro induced injury. LDL deficiency caused lower cell spreading which resulted in a decreased re-epithelisation despite the higher proliferation of MDCK cells in this medium. The re-epithelisation of keratinocytes (HaCaT) was not affected by altered LDL concentrations. In cancer cell lines A549, CaCo-2 and RT4, wide heterogeneity regarding cell proliferation and spreading capability was observed after treatment with different LDL concentrations. LDL had no influence on actin filament and tight junction distribution in any of the tested cell lines. The cholesterol content of all cell types, except for CaCo-2 cells, proved to be independent of the LDL level. Further research of the beneficial effects of LDL is needed to prove LDL as a safe enhancer of epithelial wound healing.


Scientific Reports | 2018

Detection of Chlamydiaceae and Chlamydia-like organisms on the ocular surface of children and adults from a trachoma-endemic region

Ehsan Ghasemian; Aleksandra Inic-Kanada; Astrid Collingro; Florian Tagini; Elisabeth Stein; Hadeel Alchalabi; Nadine Schuerer; Darja Keše; Balgesa Elkheir Babiker; Nicole Borel; Gilbert Greub; Talin Barisani-Asenbauer

Trachoma, the leading infectious cause of blindness, is caused by Chlamydia trachomatis (Ct), a bacterium of the phylum Chlamydiae. Recent investigations revealed the existence of additional families within the phylum Chlamydiae, also termed Chlamydia-like organisms (CLOs). In this study, the frequency of Ct and CLOs was examined in the eyes of healthy Sudanese (control) participants and those with trachoma (case). We tested 96 children (54 cases and 42 controls) and 93 adults (51 cases and 42 controls) using broad-range Chlamydiae and Ct-specific (omcB) real-time PCR. Samples positive by broad-range Chlamydiae testing were subjected to DNA sequencing. Overall Chlamydiae prevalence was 36%. Sequences corresponded to unclassified and classified Chlamydiae. Ct infection rate was significantly higher in children (31.5%) compared to adults (0%) with trachoma (p < 0.0001). In general, 21.5% of adults and 4.2% of children tested positive for CLOs (p = 0.0003). Our findings are consistent with previous investigations describing the central role of Ct in trachoma among children. This is the first study examining human eyes for the presence of CLOs. We found an age-dependent distribution of CLO DNA in human eyes with significantly higher positivity in adults. Further studies are needed to understand the impact of CLOs in trachoma pathogenicity and/or protection.


European Journal of Clinical Microbiology & Infectious Diseases | 2018

Clinical characteristics of infections caused by Mycoplasma pneumoniae P1 genotypes in children

Jasna Rodman Berlot; Uros Krivec; Marina Praprotnik; Tatjana Mrvič; Rok Kogoj; Darja Keše

Mycoplasma pneumoniae (M. pneumoniae) isolates can be classified into two major genetic groups, P1 type 1 (MP1) and P1 type 2 (MP2), based on the DNA sequence of the P1 adhesion protein gene. The aim of our study was to determine if M. pneumoniae P1 genotype is associated with disease manifestation and severity of acute M. pneumoniae infection. We compared epidemiological and clinical data of children infected with either MP1 or MP2. In addition, we separately analysed data of patients presenting with individual manifestations of M. pneumoniae infection. Data of 356 patients infected with MP1 were compared with those of 126 patients infected with MP2. MP2-infected children presented with higher median baseline C-reactive protein levels and were admitted to the hospital more often. The distribution of P1 genotype varied among groups of patients with different manifestations of M. pneumoniae infection. MP2 was more common than MP1 among patients with neurological and cardiovascular manifestations, whereas MP1 was more prevalent in other manifestations. The results from our large cohort indicate that the two P1 subtypes may have different pathogenic potential and that infections with MP2 strains could be more virulent than those with MP1 strains.

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Rok Kogoj

University of Ljubljana

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Marina Praprotnik

Boston Children's Hospital

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Marjeta Zorc

University of Ljubljana

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Mateja Legan

University of Ljubljana

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Jasna Rodman

Boston Children's Hospital

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Uros Krivec

Boston Children's Hospital

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