| 1. |
- Anthoni, Sari, et al.
(författare)
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Milk protein IgG and IgA : the association with milk-induced gastrointestinal symptoms in adults
- 2009
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Ingår i: World Journal of Gastroenterology. - : Baishideng Publishing Group Inc.. - 1007-9327 .- 2219-2840. ; 15:39, s. 4915-4918
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Tidskriftsartikel (refereegranskat)abstract
- AIM: To study the association between serum levels of milk protein IgG and IgA antibodies and milk-related gastrointestinal symptoms in adults. METHODS: Milk protein IgG and IgA antibodies were determined in serum samples of 400 subjects from five outpatient clinics in Southern Finland. Subjects were randomly selected from a total of 1900 adults undergoing laboratory investigations in primary care. All 400 participants had completed a questionnaire on abdominal symptoms and dairy consumption while waiting for the laboratory visit. The questionnaire covered the nature and frequency of gastrointestinal problems, the provoking food items, family history and allergies. Twelve serum samples were disqualified due to insufficient amount of sera. The levels of specific milk protein IgG and IgA were measured by using the ELISA technique. The association of the milk protein-specific antibody level was studied in relation to the milk-related gastrointestinal symptoms and dairy consumption. RESULTS: Subjects drinking milk (n = 265) had higher levels of milk protein IgG in their sera than non-milk drinkers (n = 123, P < 0.001). Subjects with gastrointestinal problems related to milk drinking (n = 119) consumed less milk but had higher milk protein IgG levels than those with no milk-related gastrointestinal symptoms (n = 198, P = 0.02). Among the symptomatic subjects, those reporting dyspeptic symptoms had lower milk protein IgG levels than non-dyspeptics (P < 0.05). However, dyspepsia was not associated with milk drinking (P = 0.5). The association of high milk protein IgG levels with constipation was close to the level of statistical significance. Diarrhea had no association with milk protein IgG level (P = 0.5). With regard to minor symptoms, flatulence and bloating (P = 0.8), were not associated with milk protein IgG level. Milk protein IgA levels did not show any association with milk drinking or abdominal symptoms. The levels of milk protein IgA and IgG declined as the age of the subjects increased (P < 0.004). CONCLUSION: Milk protein IgG but not milk IgA seems to be associated with self-reported milk-induced gastrointestinal symptoms.
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| 2. |
- Beeching, Nick J., et al.
(författare)
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Training and assessment of medical specialists in clinical microbiology and infectious diseases in Europe
- 2021
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Ingår i: Clinical Microbiology and Infection. - : Elsevier. - 1198-743X .- 1469-0691. ; 27:11, s. 1581-1588
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Forskningsöversikt (refereegranskat)abstract
- Background: There is wide variation in the availability and training of specialists in the diagnosis and management of infections across Europe. Objectives: To describe and reflect on the current objectives, structure and content of European curricula and examinations for the training and assessment of medical specialists in Clinical (Medical) Microbiology (CM/MM) and Infectious Diseases (ID). Sources: Narrative review of developments over the past two decades and related policy documents and scientific literature. Content: Responsibility for curricula and examinations lies with the European Union of Medical Specialists (UEMS). The ID Section of UEMS was inaugurated in 1997 and the MM Section separated from Laboratory Medicine in 2008. The sections collaborate closely with each other and the European Society of Clinical Microbiology and Infectious Diseases (ESCMID). Updated European Training Requirements (ETR) were approved for MM in 2017 and ID in 2018. These comprehensive curricula outline the framework for delivery of specialist training and quality control for trainers and training programmes, emphasizing the need for documented, regular formative reviews of progress of trainees. Competencies to be achieved include both specialty-related and generic knowledge, skills and professional behaviours. The indicative length of training is typically 5 years; a year of clinical training is mandated for CM/MM trainees and 6 months of microbiology laboratory training for ID trainees. Each Section is developing examinations using multiple choice questions to test the knowledge base defined in their ETR, to be delivered in 2022 following pilot examinations in 2021. Implications: The revised ETRs and European examinations for medical specialists in CM/MM and ID provide benchmarks for national authorities to adapt or adopt locally. Through harmonization of postgraduate training and assessment, they support the promotion and recognition of high standards of clinical practice and hence improved care for patients throughout Europe, and improved mobility of trainees and specialists. Nick J. Beeching, Clin Microbiol Infect 2021;27:1581 (c) 2021 The Author(s). Published by Elsevier Ltd on behalf of European Society of Clinical Microbiology and Infectious Diseases. This is an open access article under the CC BY license (http://creativecommons. org/licenses/by/4.0/).
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| 3. |
- Davies, Emma, et al.
(författare)
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Genomic and Phenotypic Characterisation of Campylobacter jejuni Isolates From a Waterborne Outbreak
- 2020
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Ingår i: Frontiers in Cellular and Infection Microbiology. - : FRONTIERS MEDIA SA. - 2235-2988. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- Campylobacter infections are the leading cause of bacterial gastroenteritis. In Europe, over 246,000 cases are confirmed annually. Infections are often transmitted via contaminated food, such as poultry products, but water may be the source of infection as well. The aim of this study was to characterise a selection of Campylobacter jejuni human isolates, together with a water isolate, from a waterborne outbreak in Norway in 2019, including human isolates from early, mid-, and late epidemic. The isolates were characterised with whole-genome sequencing, analysing the expression of putative virulence genes and demonstrating the pathogenic potential in an in vitro adhesion model using HT-29 cells. All isolates belonged to the multilocus sequence type 1701 and ST45 clonal complex. In the genomic analysis, the water isolate clustered somewhat separately from the human isolates. There was some variation between the human isolates, but the water isolate seemed to display the greatest pathogenic potential, demonstrated by the highest levels of virulence gene expression, adhesion to epithelial cells and IL-8 induction. These results suggest that the water isolate of the study has potential to cause human infections, and that some bacterial changes due to host or environmental adaptation, may occur during a waterborne Campylobacter epidemic. This is, to the best of our knowledge, the first study on C. jejuni isolates from a waterborne outbreak, including both human isolates and a water isolate, characterised with genomic and phenotypic approaches.
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| 4. |
- de Haan, Caroline P. A., et al.
(författare)
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Decreasing trend of overlapping multilocus sequence types between human and chicken Campylobacter jejuni isolates over a decade in Finland
- 2010
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Ingår i: Applied and Environmental Microbiology. - 0099-2240 .- 1098-5336. ; 76:15, s. 5228-5236
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Tidskriftsartikel (refereegranskat)abstract
- We describe the long-term multilocus sequence typing (MLST) analysis of the population structure and dynamics of 454 Finnish human Campylobacter jejuni isolates, as well as 208 chicken isolates, collected during the mid-1990s to 2007. The sequence type clonal complexes (ST CC) ST-45 CC, ST-21 CC, and ST-677 CC were the most common ones found among all isolates, and they covered 73.9% of all isolates. The ST-283 CC also was found frequently among chicken isolates (8.2%). The predominant STs among all isolates were ST-45, ST-50, and ST-677. ST-137 and ST-230 were common among human isolates, and ST-267 was found more frequently among chicken isolates than human isolates. The ST-45 CC was significantly associated with chicken isolates (P < 0.01), whereas the ST-21 CC was associated with human isolates (P < 0.001). The ST-677 CC was not associated with any host (P = 0.5), and an opposite temporary trend of this complex was seen among chicken and human isolates, with an increase in the former and a decrease in the latter during the study period. Furthermore, the ST-22 and ST-48 CCs were significantly associated with human isolates (P < 0.01), but neither of the CCs was found in chicken isolates. The annual overlap between STs from human and chicken isolates decreased from 76% at the beginning of the study to 58% at the end. Our results suggest that the importance of chicken as a reservoir for strains associated with human infections has declined despite the consumption of domestic chicken meat increasing during the follow-up period by 83%.
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| 5. |
- Dicksved, Johan, et al.
(författare)
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Susceptibility to Campylobacter Infection Is Associated with the Species Composition of the Human Fecal Microbiota
- 2014
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Ingår i: mBio. - 2161-2129 .- 2150-7511. ; 5:5, s. e01212-14-
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Tidskriftsartikel (refereegranskat)abstract
- The gut microbiota is essential for human health, but very little is known about how the composition of this ecosystem can influence and respond to bacterial infections. Here we address this by prospectively studying the gut microbiota composition before, during, and after natural Campylobacter infection in exposed poultry abattoir workers. The gut microbiota composition was analyzed with 16S amplicon sequencing of fecal samples from poultry abattoir workers during the peak season of Campylobacter infection in Sweden. The gut microbiota compositions were compared between individuals who became culture positive for Campylobacter and those who remained negative. Individuals who became Campylobacter positive had a significantly higher abundance of Bacteroides (P = 0.007) and Escherichia (P = 0.002) species than those who remained culture negative. Furthermore, this group had a significantly higher abundance of Phascolarctobacterium (P = 0.017) and Streptococcus (P = 0.034) sequences than the Campylobacter-negative group, which had an overrepresentation of Clostridiales (P = 0.017), unclassified Lachnospiraceae (P = 0.008), and Anaerovorax (P = 0.015) sequences. Intraindividual comparisons of the fecal microbiota compositions yielded small differences over time in Campylobacter-negative participants, but significant long-term changes were found in the Campylobacter-positive group (P < 0.005). The results suggest that the abundance of specific genera in the microbiota reduces resistance to Campylobacter colonization in humans and that Campylobacter infection can have long-term effects on the composition of the human fecal microbiota. IMPORTANCE Studies using mouse models have made important contributions to our understanding of the role of the gut microbiota in resistance to bacterial enteropathogen colonization. The relative abundances of Escherichia coli and Bacteroides species have been pointed out as important determinants of susceptibility to Gram-negative pathogens in general and Campylobacter infection in particular. In this study, we assessed the role of the human gut microbiota in resistance to Campylobacter colonization by studying abattoir workers that are heavily exposed to these bacteria. Individuals with a certain composition of the gut microbiota became culture positive for Campylobacter. As their microbiotas were characterized by high abundances of Bacteroides spp. and E. coli, well in line with the findings with mouse models, these bacterial species likely play an important role in colonization resistance also in humans.
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| 6. |
- Ellström, Patrik, et al.
(författare)
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A Prospective Follow-Up Study on Transmission of Campylobacter from Poultry to Abattoir Workers
- 2014
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Ingår i: Foodborne Pathogens and Disease. - : Mary Ann Liebert Inc. - 1535-3141 .- 1556-7125. ; 11:9, s. 684-688
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Tidskriftsartikel (refereegranskat)abstract
- Contact with poultry or poultry meat is a well-known risk factor for campylobacteriosis, but prospective studies on transmission of Campylobacter from chickens to humans during slaughter are scarce. In this study, we monitored transmission of Campylobacter from slaughtered chicken to originally culture-negative abattoir workers during the peak season of colonized chicken and human Campylobacter infection. Stool samples were obtained from 28 abattoir workers together with data on health status once a month between June and September 2010, with a follow-up sample collected in February 2011. Campylobacter-positive individuals and chicken flocks were identified by culture, and isolates were further characterized using molecular techniques. Campylobacter was isolated from seven asymptomatic individuals. Four of them had been newly employed and had not reported any previous Campylobacter infection. Four human isolates had matching genetic fingerprints with isolates from recently slaughtered chickens. Our results further support the role of chicken as the source of human Campylobacter infection but suggest that asymptomatic Campylobacter infection may occur even in individuals with only limited earlier exposure to Campylobacter.
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| 7. |
- Ellström, Patrik, et al.
(författare)
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Characterization of clinical Campylobacter jejuni isolates with special emphasis on lipooligosaccharide locus class, putative virulence factors and host response
- 2013
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Ingår i: International Journal of Medical Microbiology. - : Elsevier BV. - 1438-4221 .- 1618-0607. ; 303:3, s. 134-139
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Tidskriftsartikel (refereegranskat)abstract
- Recent studies have indicated a role of the lipooligosaccharide (LOS) of Campylobacter jejuni in the severe neurological Guillain Barre syndrome, as well as in development of more severe symptoms of acute enteritis. We evaluated the role of the LOS locus class in C jejuni infection among 163 enteritis patients. The prevalence of LOS locus classes differed according to the origin of the isolates. Furthermore, LOS locus classes A and B were significantly associated with susceptibility or resistance to ciprofloxacin and doxycycline. However, our results do not corroborate earlier findings that isolates with potential to sialylate LOS might be associated with more severe symptoms of enteritis. Instead, in an infection model, such isolates gave weaker epithelial IL-8 responses than nonsialylated isolates. Absence of the iron transport protein encoded by the gene ceuE as well as the putative fucose permease gene cj0486 was associated with increased in vitro IL-8 secretion.
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| 8. |
- Ellström, Patrik, et al.
(författare)
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Lipooligosaccharide locus class of Campylobacter jejuni : sialylation is not needed for invasive infection
- 2014
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Ingår i: Clinical Microbiology and Infection. - : Elsevier BV. - 1198-743X .- 1469-0691. ; 20:6, s. 524-529
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Tidskriftsartikel (refereegranskat)abstract
- Campylobacter jejuni is a highly diverse enteropathogen that is commonly detected worldwide. It can sometimes cause bacteraemia, but the bacterial characteristics facilitating bloodstream infection are not known. A total of 73 C. jejuni isolates, consecutively collected from blood-borne infections during a 10-year period all over Finland and for which detailed clinical information of the patients were available, were included. We screened the isolates by PCR for the lipooligosaccharide (LOS) locus class and for the presence of the putative virulence genes ceuE, ciaB, fucP, and virB11. The isolates were also tested for gamma-glutamyl transpeptidase production. The results were analysed with respect to the clinical characteristics of the patients, and the multilocus sequence types (MLSTs) and serum resistance of the isolates. LOS locus classes A, B, and C, which carry genes for sialylation of LOS, were detected in only 23% of the isolates. These isolates were not more resistant to human serum than those with the genes of non-sialylated LOS locus classes, but were significantly more prevalent among patients with underlying diseases (p 0.02). The fucose permease gene fucP was quite uncommon, but was associated with the isolates with the potential to sialylate LOS (p <0.0001). LOS locus classes and some of the putative virulence factors were associated with MLST clonal complexes. Although some of the bacterial characteristics studied here have been suggested to be important for the invasiveness of C. jejuni, they did not explain why the clinical isolates in the present study were able to cause bacteraemia.
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| 9. |
- Ellström, Patrik, et al.
(författare)
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Lipooligosaccharide locus classes and putative virulence genes among chicken and human Campylobacter jejuni isolates
- 2016
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Ingår i: BMC Microbiology. - : Springer Science and Business Media LLC. - 1471-2180. ; 16
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Tidskriftsartikel (refereegranskat)abstract
- Background: Campylobacter cause morbidity and considerable economic loss due to hospitalization and post infectious sequelae such as reactive arthritis, Guillain Barr-and Miller Fischer syndromes. Such sequelae have been linked to C. jejuni harboring sialic acid structures in their lipooligosaccharide (LOS) layer of the cell wall. Poultry is an important source of human Campylobacter infections but little is known about the prevalence of sialylated C. jejuni isolates and the extent of transmission of such isolates to humans. Results: Genotypes of C. jejuni isolates from enteritis patients were compared with those of broiler chicken with pulsed-field gel electrophoresis (PFGE), to study the patterns of LOS biosynthesis genes and other virulence associated genes and to what extent these occur among Campylobacter genotypes found both in humans and chickens. Chicken and human isolates generally had similar distributions of the putative virulence genes and LOS locus classes studied. However, there were significant differences regarding LOS locus class of PFGE types that were overlapping between chicken and human isolates and those that were distinct to each source. Conclusions: The study highlights the prevalence of virulence associated genes among Campylobacter isolates from humans and chickens and suggests possible patterns of transmission between the two species.
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| 10. |
- Feodoroff, Benjamin, et al.
(författare)
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A Nationwide Study of Campylobacter jejuni and Campylobacter coli Bacteremia in Finland over a 10-Year Period, 1998-2007, with Special Reference to Clinical Characteristics and Antimicrobial Susceptibility
- 2011
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Ingår i: Clinical Infectious Diseases. - : Oxford University Press (OUP). - 1058-4838 .- 1537-6591. ; 53:8, s. e99-e106
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Tidskriftsartikel (refereegranskat)abstract
- Background: Campylobacter bacteremia is an uncommon condition, usually diagnosed in elderly and immunocompromised patients.Methods: Blood culture isolates and clinical information were collected for patients with diagnoses of Campylobacter jejuni or Campylobacter coli bacteremia in Finland from 1998 through 2007. Bacterial species were identified by means of polymerase chain reaction analysis, and minimal inhibitory concentrations for ciprofloxacin, clindamycin, doxycycline, erythromycin, gentamicin, meropenem, and metronidazole were determined with an agar dilution method. Medical records and mortality data within 1 year after the bacteremic episode were reviewed.Results: The study included 76 patients (median age, 46 years), for whom bacterial isolates (C. jejuni in 73, C. coli in 3) and clinical information were available. Most patients (70%) had no significant underlying diseases. The majority (82%) of the isolates were susceptible for all antimicrobial agents tested. However, antimicrobial therapy seemed to have only a limited effect, because no differences could be detected between patients with appropriate empirical antimicrobial treatment and those with delayed appropriate, inappropriate, or no antimicrobial therapy, either in the duration of hospitalization (median, 4 days for both groups) or in attributable mortality. The outcome of the infection was severe in 4 patients infected with C. jejuni; 2 died within 30 days, spondylodiscitis developed in 1, and Guillain-Barré syndrome developed in 1.Conclusions: C. jejuni and C. coli bacteremia occurred mainly in moderately young individuals without severe underlying diseases. The bacterial isolates were predominantly susceptible to antimicrobial agents, and the outcome of the disease was typically good, regardless of appropriate or inappropriate antimicrobial treatment given in the hospital.
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| 11. |
- Feodoroff, Benjamin, et al.
(författare)
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Campylobacter jejuni isolates in Finnish patients differ according to the origin of infection
- 2010
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Ingår i: Gut Pathogens. - : Springer Science and Business Media LLC. - 1757-4749. ; 2:1
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Tidskriftsartikel (refereegranskat)abstract
- ABSTRACT: BACKGROUND: Campylobacter jejuni is a significant cause of bacterial enteritis worldwide. Very little is known about the pathogenicity mechanisms and virulence factors of this important enteropathogen. C. jejuni isolates from 166 Finnish patients, collected from July to December in 2006, were studied for the presence of putative virulence factors and susceptibility to antimicrobials. Isolates were tested for production of gamma-glutamyltransferase (GGT) as well as the presence of genes ceuE, cgtB, ciaB, cj0486, pldA, virB11, wlaN, and the gene cluster cdtABC. Bacterial characteristics were compared to information on foreign travel history as well as information on the course and the symptoms of disease obtained from questionnaires returned by patients. RESULTS: Except for one domestic isolate, antimicrobial resistance was only detected in isolates of foreign origin. Univariate analyses showed association between bloody stools and both GGT production (p=0.025) and the presence of cgtB (p=0.034). Multivariate analysis verified that GGT production was more prevalent in domestic isolates (p<0.0001), while the genes cj0486 (p<0.0001) and ceuE (p<0.0001) were associated with C. jejuni isolates of foreign origin. CONCLUSIONS: The results indicate that imported and domestic C. jejuni isolates differ significantly in several aspects from each other.
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| 12. |
- Feodoroff, Benjamin, et al.
(författare)
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Clonal Distribution and Virulence of Campylobacter jejuni Isolates in Blood
- 2013
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Ingår i: Emerging Infectious Diseases. - : Centers for Disease Control and Prevention (CDC). - 1080-6040 .- 1080-6059. ; 19:10, s. 1653-1655
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Tidskriftsartikel (refereegranskat)abstract
- Campylobacter jejuni bacteria are highly diverse enteropathogens. Seventy-three C. jejuni isolates from blood collected in Finland were analyzed by multilocus sequence typing and serum resistance. Approximately half of the isolates belonged to the otherwise uncommon sequence type 677 clonal complex. Isolates of this clonal complex were more resistant than other isolates to human serum.
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| 13. |
- Gonzalez, Manuel, et al.
(författare)
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Bovine Campylobacter jejuni strains differ from human and chicken strains in an analysis of certain molecular genetic markers
- 2009
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Ingår i: Applied and Environmental Microbiology. - 0099-2240 .- 1098-5336. ; 75:4, s. 1208-1210
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Tidskriftsartikel (refereegranskat)abstract
- The association of four new genetic markers with a chicken, bovine, or human host was studied among 645 Campylobacter jejuni isolates. The gamma-glutamate transpeptidase gene and dmsA were common in human and chicken isolates but uncommon among bovine isolates. In the t test, bovine isolates differed significantly (P < 0.05) from human and chicken isolates.
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| 14. |
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| 15. |
- Johansson, Cecilia, et al.
(författare)
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Campylobacter coli clade 3 isolates induce rapid cell death in vitro
- 2019
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Ingår i: Applied and Environmental Microbiology. - 0099-2240 .- 1098-5336. ; 85:5
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Tidskriftsartikel (refereegranskat)abstract
- Campylobacter are major human enteropathogens. C. coli show less genetic diversity than C. jejuni and cluster into three clades, of which clade 1 includes most human and farm animal isolates while environmental C. coli mainly belong to clades 2 and 3. Recently, we whole genome-sequenced eight C. coli clade 2 and 3 isolates cultivated from water, and here we studied their interaction with human HT-29 colon cancer cells compared to clinical clade 1 isolates. All C. coli clade 3 isolates caused cell necrosis already 1-2 hours after inoculation, whereas none of the clade 1 and 2 isolates analyzed induced cell death. Isolates from clades 2 and 3 adhered better than clade 1 isolates to epithelial cells but all isolates induced similar levels of IL-8. Alignment and phylogenetic analysis of translated putative virulence genes cadF, flpA, iamA, ciaB and ceuE revealed clade-specific protein sequence variations with clade 1 and 2 sequences more closely related and clade 3 sequences further apart in general.Moreover, when RNA levels were measured, clade 3 isolates showed a significantly lower expression of cadF, iamA and ceuE than clade 2 isolates, while flpA levels were higher in clade 3 isolates. The cytolethal distending toxin genes were also expressed in clades 2 and 3 although there was no difference between clades. Our findings demonstrate differences between effects of C. coli clade 1, 2 and 3 isolates on human cells and suggest that C. coli clade 3 might be more virulent than clade 2 due to the observed cytotoxicity.IMPORTANCECampylobacter coli is a common zoonotic cause of gastroenteritis in humans worldwide. The majority of infections are caused by C. coli clade 1 isolates, whereas infections due to clade 2 and 3 isolates are rare. Whether this depends on a low prevalence of clade 2 and 3 isolates in reservoirs important for human infections or their lower ability to cause human disease is unknown. Here, we studied the effects of C. coli clade 2 and 3 isolates on a human cell line. These isolates adhered to human cells to a higher degree than clinical clade 1 isolates. Furthermore, we could show that C. coli clade 3 isolates rapidly induced cell death suggesting differences in the virulence of C. coli The exact mechanism of cell death remains to be revealed but selected genes showed interesting clade-specific expression patterns.
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| 16. |
- Johansson, Cecilia, et al.
(författare)
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Differences in virulence gene expression between human blood and stool Campylobacter coli clade 1 ST828CC isolates
- 2019
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Ingår i: Gut Pathogens. - : BioMed Central. - 1757-4749. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: Campylobacter colonise the gastrointestinal tract of warm-blooded animals and are major enteropathogens in humans. C. coli is less common than C. jejuni and accounts for about 10% of the total number of Campylobacter infections although the two species seem to share many virulence determinants. Campylobacter bacteraemia is rare, estimated to occur in less than 1% of the infections, and the exact mechanisms regulating the progression of the infection from the gastrointestinal tract to the blood stream are unclear. Here, we looked at the contribution of C. coli to Campylobacter infections and further compared various virulence traits in C. coli clade 1 blood and stool isolates. Results: We assessed the numbers of C. jejuni and C. coli among typed isolates in the PubMLST database and found that C. coli accounted for 25.9% of blood isolates, but only 8.9% of the stool isolates. Phylogenetic analysis of 128 C. coli clade 1 whole genome sequences deposited to NCBI revealed no specific clustering of the human blood, stool or animal isolates. Of the six C. coli isolates chosen for phenotypic analyses, stool isolates adhered significantly better to human HT-29 colon cancer cells than the blood isolates, while there was no difference in induced IL-8 levels between the isolates. Furthermore, the stool isolates had two-to fourfold higher RNA expression levels of the flpA, ciaB, iamA and cdt virulence genes than the blood isolates. Finally, we looked at the gene structure of the cdtA, B and C toxin genes and found numerous nucleotide additions and deletions disrupting the open reading frames. In contrast to 58% isolates of animal origin, only 38% and 32% of human blood and stool isolates, respectively, had all three cdt genes intact, a prerequisite to produce functional toxins. Conclusions: This study reveals interesting differences between C. coli clade 1 isolates of human and animal origin on one hand, and also between human blood and stool isolates, on the other. The results suggest that C. coli might downregulate and/or inactivate various virulence determinants as the isolates pass from the animal host to the human gastrointestinal tract and enter the human blood stream.
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| 17. |
- Johansson, Cecilia, et al.
(författare)
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Genomic and Phenotypic Characteristics in Geographically Separated Clinical Campylobacter jejuni ST353CC Isolates
- 2021
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Ingår i: Microorganisms. - : MDPI. - 2076-2607. ; 9:12
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Tidskriftsartikel (refereegranskat)abstract
- Campylobacter jejuni fecal isolates of eight international travelers, 5 of which had traveled to Ecuador and 3 to Bangladesh, were characterized, and the possible relationship between bacterial traits and clinical symptoms was further analyzed. All eight isolates belonged to the same Multi-Locus Sequence Type clonal complex (ST353CC). The three isolates from Bangladesh were all of the same sequence type (ST-9438), and when compared to isolates of various other sequence types, they had a larger quantity of unique genetic content, higher expression levels of some putative virulence genes involved in adhesion and invasion (flpA, ciaB and iamA), and showed higher adhesion levels to human HT-29 colon cancer cells in an in vitro infection model. However, in contrast to the seemingly higher pathogenic potential of these bacterial isolates, travelers infected with the ST-9438 isolates had no or only very mild symptoms, whereas the other individuals, whose bacterial isolates seemed to have less pathogenic potential, generally reported severe symptoms. When studying the 16S rRNA gene-based fecal microbiota in samples collected prior to travel, there was an individual variation in the relative abundance of the three major bacterial phyla Actinobacteria, Bacteroidetes and Firmicutes, but there were no associations between composition and diversity of microbiota and development of severe symptoms from the infection. It remains to be confirmed by larger studies whether an individual's characteristics such as gut microbiota, might be related to the severity of symptoms in Campylobacter infections.
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| 18. |
- Johansson, Cecilia, et al.
(författare)
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Staphylococcus argenteus and Staphylococcus schweitzeri are cytotoxic to human cells in vitro due to high expression of alpha-hemolysin Hla
- 2019
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Ingår i: Virulence. - : Taylor & Francis. - 2150-5594 .- 2150-5608. ; 10:1, s. 502-510
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Tidskriftsartikel (refereegranskat)abstract
- Staphylococcus argenteus and Staphylococcus schweitzeri are newly identified species of the S. aureus-related complex. S. argenteus, as occurring globally and showing significant prevalence and comparable infection and morbidity rates compared to S. aureus, is becoming clinically important. Whole genome sequencing has revealed the presence of several virulence genes but the molecular mechanisms of S. argenteus infection and virulence are largely unknown. Here, we studied the effect of a previously characterized clinical S. argenteus isolate on human cells in vitro. The clinical isolate, together with the S. argenteus type strain MSHR1132T and the S. schweitzeri type strain FSA084T, had a cytotoxic effect on the cells, which showed necrotic cell death after a few hours of treatment. The protein causing the cytotoxic effect was purified and identified by mass spectrometry as alpha-hemolysin, Hla, which is awell-known pore-forming toxin in S.aureus. The cytotoxic effect could be blocked with an antibody against Hla. S.argenteus showed 12-15 fold higher expression levels of hla at the RNA level and 4-6 fold higher expression levels at the protein level compared to S.aureus. The higher expression levels of hla were supported by higher RNA levels of the regulatory factors sarA and saeR. Also, the RNAIII component of the accessory gene regulator (agr) quorum sensing system was 8,000-10,000 fold higher in the S.argenteus isolates compared to S.aureus. This is the first study on the effect of S.argenteus on ahuman cell line and strengthens the idea of significant virulence of S.argenteus.
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| 19. |
- Kaden, Rene, 1975-, et al.
(författare)
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Which methods are appropriate for the detection of Staphylococcus argenteus and is it worthwhile to distinguish S. argenteus from S. aureus?
- 2018
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Ingår i: Infection and Drug Resistance. - 1178-6973. ; 11, s. 2335-2344
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To further analyze a clinical isolate originally identified as methicillin-resistant Staphylococcus aureus (MRSA) using whole-genome sequencing and comparative genomics.Materials and methods: Classical diagnostic methods such as cultivation, biochemical tests, and PCR were supplemented with whole-genome sequencing and comparative genomics, to identify the isolate.Results: The isolate was phenotypically similar to MRSA. However, the presence of the nuc gene could not be confirmed using PCR, while it was positive for the mecA gene. Whole-genome sequencing correctly identified the isolate as Staphylococcus argenteus. The isolate possessed several resistance genes, such as mecA, blaZ (beta-lactam antibiotics) and dfrG (trimethoprim). The me gene differed from that of MRSA. Six phylogenetic distinct clusters were identified by average nucleotide identity (ANI) analysis of all available S. argenteus whole-genome sequences. Our isolate, RK308, clustered with those isolated in Europe and Asia.Conclusion: Due to the invasive potential, the multi-drug resistance and the similarity to MRSA, S. argenteus should be included in the MRSA screening. Due to the divergent genome compared to MRSA, new PCR approaches have to be developed to avoid an unnoticed spreading of S. argenteus.
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| 20. |
- Kampmann, Christian, et al.
(författare)
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Changes to human faecal microbiota after international travel
- 2021
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Ingår i: Travel Medicine and Infectious Disease. - : Elsevier. - 1477-8939 .- 1873-0442. ; 44
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Tidskriftsartikel (refereegranskat)abstract
- Background:The aim was to investigate whether travelling to less-resourced destinations influences the faecal microbiota in generally healthy adults.Method:In this prospective observational study, 47 adults (median age, 24 years; 73% females) travelled from Sweden to distant destinations for 1-12 weeks. Five faecal samples, two before and three after travel, were analysed by 16S amplicon massive parallel sequencing. Subjects had taken no antibiotics within three months of each sampling. Results:The overall composition of the faecal microbiota was not affected by travel. However, when looking at the relative abundance of individual bacterial taxa, Enterobacteriaceae demonstrated a 10-fold increase immediately after the trip as compared to the samples taken before travelling. Conversely, the relative abundance of Christensenellaceae had decreased equally much. Both of these changes were reversible within nine weeks. Conclusions:International travel, even to less-resourced countries, did not appear to alter the overall diversity of human faecal microbiota as studied here after travelling. However, Enterobacteriaceae bacteria, often associated with infection, inflammation and antibiotic resistance, showed dramatically elevated levels, and Christensenellaceae, frequently associated with healthy conditions, demonstrated remarkably declined levels in relative abundance as detected immediately after travel. In both cases, these changes returned to original pre-travel levels within nine weeks.
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| 21. |
- Kampmann, C., et al.
(författare)
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Composition of human faecal microbiota in resistance to Campylobacter infection
- 2016
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Ingår i: Clinical Microbiology and Infection. - : Elsevier BV. - 1198-743X .- 1469-0691. ; 22:1, s. 1-61
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Tidskriftsartikel (refereegranskat)abstract
- In mice, specific species composition of gut microbiota enhances susceptibility to Campylobacter jejuni but little is known about the specific composition of the human gut microbiota in providing protection from infections caused by enteropathogens. Healthy adult individuals, who travelled in groups from Sweden to destinations with an estimated high risk for acquisition of Campylobacter infection, were enrolled. Faecal samples, collected before travelling and after returning home, were cultured for bacterial enteropathogens, and analysed for Campylobacter by PCR and for the species composition of the microbiota by 16S amplicon massive parallel sequencing. The microbiota compositions were compared between persons who became infected during their travel and those who did not. A total of 63 participants completed the study; 14 became infected with Campylobacter, two with Salmonella and 47 remained negative for the enteropathogens tested. After exclusion of samples taken after antimicrobial treatment, 49 individuals were included in the final analyses. Intra-individual stability of the microbiota was demonstrated for samples taken before travelling. The original diversity of the faecal microbiota was significantly lower among individuals who later became infected compared with those who remained uninfected. The relative abundances of bacteria belonging to the family Lachnospiraceae, and more specifically its two genera Dorea and Coprococcus, were significantly higher among those who remained uninfected. The travel-related infection did not significantly modify the faecal microbiota composition. Species composition of human gut microbiota is important for colonization resistance to Campylobacter infection. Especially individuals with a lower diversity are more susceptible to Campylobacter infection.
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| 22. |
- Kampmann, Christian, 1975-
(författare)
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Go with your gut : The human intestinal microbiota, international travel, Campylobacter and ESBL-producing Enterobacteriaceae
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Up to 100 million people travel annually from industrialized countries to resource-limited ones. Each traveller contains an internal ecosystem composed of tens of trillions of microbes, known as the intestinal microbiota, which has a large effect on health. The microbiota seems to be highly individual and mostly stable but can be significantly affected by several factors. Many international travellers are at high risk of getting infected by Campylobacter, the most common cause of bacterial enteritis worldwide. Campylobacter infection can cause a wide range of symptoms, with varying severity, for reasons largely unknown. Travel also radically increases the risk of colonization by antibiotic-resistant intestinal bacteria, notably Extended spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae (EPE). To date, there are no therapies available for EPE-decolonization. In this thesis, it was investigated whether the bacterial intestinal microbiota affected susceptibility to Campylobacter and if international travel as such had an impact on the microbiota. In a prospective, observational study, 67 healthy Swedes, travelling in groups to countries with a high risk of Campylobacter infection, were followed. The travellers answered questionnaires and delivered two faecal samples before and three samples after the trip. These samples were cultured for enteropathogens and analysed for the microbiota composition. Low diversity of microbiota seemed to increase the risk of Campylobacter jejuni infection, whereas a high relative abundance of Lachnospiraceae might decrease the risk (Paper I). Furthermore, the overall bacterial diversity did not seem to change in connection with travelling. However, the bacterial family Enterobacteriaceae (otherwise connected with inflammation, infection and antibiotic-resistance) was shown to be dramatically increased in abundance immediately after travel, and the family Christensenellaceae (otherwise connected with beneficial health conditions) simultaneously decreased (Paper II). Eight travellers, from two different destinations, were infected with closely related C. jejuni isolates (ST353CC). The bacterial analysis of genomic and phenotypic characteristics revealed that the C. jejuni isolates of the travellers returning from one of the destinations and with more severe symptoms actually showed less pathogenic potential, compared to the isolates of travellers from the other destination and with milder symptoms. However, the travellers with more severe symptoms had much higher relative abundances of Bacteroidetes in their intestinal microbiota and, in contrast to the other travellers, excluded meat from their diet. (Paper III) Finally, we investigated in a randomized, placebo-controlled clinical trial of 80 established intestinal carriers of EPE, whether the oral probiotic product Vivomixx® could eradicate EPE. Vivomixx® was not superior to placebo (Paper IV).
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| 23. |
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| 24. |
- Kivistö, Rauni, et al.
(författare)
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Characterization of multiple Helicobacter bizzozeronii isolates from a Finnish patient with severe dyspeptic symptoms and chronic active gastritis
- 2010
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Ingår i: Helicobacter. - : Wiley. - 1083-4389 .- 1523-5378. ; 15:1, s. 58-66
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Helicobacter pylori is the primary cause of gastritis and peptic ulceration in humans. In a minority of patients with upper gastrointestinal symptoms, long tightly coiled spiral bacteria, provisionally named "Helicobacter heilmannii," are observed in gastric biopsies. These bacteria are extremely fastidious and only one previous study has succeeded in obtaining an isolate in vitro. MATERIALS AND METHODS: We used two different selective media to isolate "H. heilmannii" from the gastric mucosa of a Finnish patient presenting with severe dyspeptic symptoms. The isolates were characterized by testing for urease and catalase activity, by using light and electron microscopy, and by sequencing of the partial 16S rRNA and ureAB genes. Single-enzyme amplified fragment length polymorphism (sAFLP) was used to analyze the genetic diversity among the isolates. RESULTS: We obtained 15 isolates from different gastric biopsies prior and three after unsuccessful treatment of the patient. The isolates were identified as Helicobacter bizzozeronii. Eradication therapy was unsuccessful most probably due to high level of resistance to metronidazole. Persistent colonization by the same H. bizzozeronii clone was confirmed by sAFLP, however, small differences between the profiles suggested long-term colonization of the patient. CONCLUSIONS: Helicobacter bizzozeronii remains the only "H. heilmannii" species isolated from human gastric mucosa although it has been an infrequent observation among "H. heilmannii"-infected patients in PCR-based screening studies. The relevance of H. bizzozeronii and other potentially zoonotic gastric Helicobacter spp. in human disease remains to be determined.
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| 25. |
- Kostamo, Pirkko, et al.
(författare)
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Recent trends in primary antimicrobial resistance of Helicobacter pylori in Finland
- 2011
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Ingår i: International Journal of Antimicrobial Agents. - : Elsevier BV. - 0924-8579 .- 1872-7913. ; 37:1, s. 22-25
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Tidskriftsartikel (refereegranskat)abstract
- The antimicrobial susceptibility of Helicobacter pylori is an important predictor of the success of eradication therapy. To evaluate recent changes in primary antimicrobial resistance of H. pylori isolated from Finnish patients, the clinical records of H. pylori-positive patients referred for endoscopy to Herttoniemi Hospital (Helsinki, Finland) during 2000-2008 were investigated retrospectively. Stored H. pylori strains from 505 patients without previous eradication therapy were tested for clarithromycin, metronidazole, levofloxacin, tetracycline and amoxicillin susceptibility by Etest. Data on local consumption of antimicrobials were collected and correlations between consumption and resistance were calculated. During the 9-year study period, metronidazole resistance was high (range 29-59%, overall 41%). After an initial increase in clarithromycin resistance (0% in 2000 to 16% in 2003), resistance to clarithromycin decreased to 4% in 2008. No significant correlation was detected between consumption of macrolides and resistance of clarithromycin. Resistance to levofloxacin varied between 0% and 12%. Primary metronidazole resistance in H. pylori is at a high level, however levofloxacin and clarithromycin resistances are still at a reasonable level. Thus, primary clarithromycin resistance in H. pylori in Finland has not become such a problem as in many other countries. Primary resistance to the antimicrobials studied varied considerably from year to year.
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