Papers by Andreas Zautner
Research Square (Research Square), May 5, 2023
Background The main natural reservoir for Campylobacter jejuni is the intestinal tract of birds, ... more Background The main natural reservoir for Campylobacter jejuni is the intestinal tract of birds, especially in the context of human nutrition chickens and turkeys play the main role. There, C. jejuni multiplies optimally at 42°C, the avian body temperature, while after infection of humans by peroral intake in the human intestinal tract only 37°C prevail. Proteome pro ling by label-free mass spectrometry (DIA-MS) was performed to examine the processes which enable C. jejuni strain 81-176 to adapt to 37°C in comparison to 42°C. In total, four states were compared with each other: incubation for 12 h at 37°C, for 24 h at 37°C, for 12 h at 42°C and 24 h at 42°C. Results It was shown that the proteome pro le changes not only according to the different incubation temperature but also with the length of the incubation period, i.e. signi cant differences in protein
PubMed, Apr 17, 2015
Campylobacter (C.) jejuni is the most important reported cause for bacterial diarrhoea. The infec... more Campylobacter (C.) jejuni is the most important reported cause for bacterial diarrhoea. The infection can be accompanied by fever and abdominal cramps and in rare cases the Guillain-Barré syndrome or reactive arthritis can develop as a post-infection complication. Several biological properties of Cjejuni, e. g. motility and chemotaxis, contribute to the biological fitness of the pathogen. For this, deficiencies in the function of these features clearly reduce the pathogenicity of C. jejuni without being a virulence factor per se. Opposing to this, there are two essential requirements to determine the virulence of C. jejuni which represent the adherence to, and the invasion of host cells. Thereby, adherence, as a virulence factor, is mediated by many different bacterial-derived components like proteins but also by several oligo- and polysaccharide structures that are linked to surface proteins but also to the flagella. In addition, several invasion-relevant features of C. jejuni have been detected so far. Whereas some of them are described functionally to modulate cytoskeleton arrangement of the host cell, others are only described as invasion relevant. Indeed, investigations with respect to the pathogenic potential of some adherence- and invasion-relevant components did not give identical results indicating that their relevance might depend on the interplay of the respective C. jejuni strains used in these studies with the corresponding host cells. This review summarizes the C. jejuni components for adherence to and invasion of host cells together with their particular mode of action if known.
Fungal Biology, Feb 1, 2016
MALDI-ToF mass spectrometry offers fast and reliable species identification for bacteria and yeas... more MALDI-ToF mass spectrometry offers fast and reliable species identification for bacteria and yeasts under clinical routine conditions. Here, we produced mass spectra for identification of clinically important species of the Pseudallescheria / Scedosporium complex using the recently suggested new nomenclature and use this example to discuss to what extent the principle of DNA barcoding might be transferred to mass spectrometry.
PLOS ONE, Nov 26, 2013
Adherence of Campylobacter jejuni to its particular host cells is mediated by several pathogen pr... more Adherence of Campylobacter jejuni to its particular host cells is mediated by several pathogen proteins. We screened a transposon-based mutant library of C. jejuni in order to identify clones with an invasion deficient phenotype towards Caco2 cells and detected a mutant with the transposon insertion in gene cj0268c. In vitro characterization of a generated nonrandom mutant, the mutant complemented with an intact copy of cj0268c and parental strain NCTC 11168 confirmed the relevance of Cj0268c in the invasion process, in particular regarding adherence to host cells. Whereas Cj0268c does not impact autoagglutination or motility of C. jejuni, heterologous expression in E. coli strain DH5a enhanced the potential of the complemented E. coli strain to adhere to Caco2 cells significantly and, thus, indicates that Cj0268c does not need to interact with other C. jejuni proteins to develop its adherence-mediating phenotype. Flow cytometric measurements of E. coli expressing Cj0268c indicate a localization of the protein in the periplasmic space with no access of its C-terminus to the bacterial surface. Since a respective knockout mutant possesses clearly reduced resistance to Triton X-100 treatment, Cj0268c contributes to the stability of the bacterial cell wall. Finally, we could show that the presence of cj0268c seems to be ubiquitous in isolates of C. jejuni and does not correlate with specific clonal groups regarding pathogenicity or pathogen metabolism.
Journal of Clinical Medicine, May 29, 2021
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Acta Tropica, May 1, 2020
Diagnostic testing in the infectious disease laboratory facilitates decision-making by physicians... more Diagnostic testing in the infectious disease laboratory facilitates decision-making by physicians at the bedside as well as epidemiological assessments and surveillance at study level. Problems may arise if test results are uncritically considered as being the same as the unknown true value. To allow a better understanding, the influence of external factors on the interpretation of test results is introduced with the example of prevalence, followed by the presentation of strengths and weaknesses of important techniques in the infectious disease laboratory like microscopy, cultural diagnostics, serology, mass spectrometry, nucleic acid amplification and hypothesis-free metagenomic sequencing with focus on basic, high-technology and potential future approaches. Special problems like multiplex testing as well as uncertainty of test evaluations, if no gold standard is available, are also stressed with a final glimpse on emerging future technologies for the infectious disease laboratory. In the conclusions, suitability for point-of-care-testing and field laboratory applications is summarized. The aim is to illustrate the limitations of diagnostic accuracy to both clinicians and study planners and to stress the importance of close cooperation with experts in laboratory disciplines so as to avoid potentially critical misunderstandings due to inappropriate interpretation of diagnostic test results.
European journal of microbiology and immunology, Mar 1, 2012
Chemotaxis is the common way of flagellated bacteria to direct their locomotion to sites of most ... more Chemotaxis is the common way of flagellated bacteria to direct their locomotion to sites of most favourable living conditions, that are sites with the highest concentrations of energy sources and the lowest amounts of bacteriotoxic substances. The general prerequisites for chemotaxis are chemoreceptors, a chemosensory signal-transduction system and the flagellar apparatus. Epsilonproteobacteria like Campylobacter sp. show specific variations of the common chemotaxis components. CheV, a CheWlike linking-protein with an additional response regulator (RR) domain, was identified as commonly used coupling scaffold protein of Campylobacter jejuni. It attaches the histidine autokinase (CheAY), which also has an additional RR-domain, to the chemoreceptors signalling domains. Theses additional RR-domains seem to play an important role in the regulation of the CheAY-phosphorylation state and thereby in sensory adaptation. The Campylobacter-chemoreceptors are arranged into the three groups A, B, and C. Group A contains membrane-anchored receptors sensing periplasmic signals, group B consists only of one receptor with two cytoplasmic ligand-proteins representing a bipartite energy taxis system that senses pyruvate and fumarate, and group C receptors are cytoplasmic signalling domains with mostly unknown cytoplasmic ligand-binding proteins as sensory constituents. Recent findings demonstrating different alleles of the TLP7 chemoreceptor, specific for formic acid, led to an amendment of this grouping.
medRxiv (Cold Spring Harbor Laboratory), Sep 3, 2020
PLOS ONE, Feb 25, 2014
Background: Although Campylobacter jejuni infections have a high prevalence worldwide and represe... more Background: Although Campylobacter jejuni infections have a high prevalence worldwide and represent a significant socioeconomic burden, the underlying molecular mechanisms of induced intestinal immunopathology are still not well understood. We have recently generated a C. jejuni mutant strain NCTC11168::cj0268c, which has been shown to be involved in cellular adhesion and invasion. The immunopathological impact of this gene, however, has not been investigated in vivo so far. Methodology/Principal Findings: Gnotobiotic IL-10 deficient mice were generated by quintuple antibiotic treatment and perorally infected with C. jejuni mutant strain NCTC11168::cj0268c, its complemented version (NCTC11168::cj0268c-comp-cj0268c), or the parental strain NCTC11168. Kinetic analyses of fecal pathogen loads until day 6 post infection (p.i.) revealed that knockout of cj0268c did not compromise intestinal C. jejuni colonization capacities. Whereas animals irrespective of the analysed C. jejuni strain developed similar clinical symptoms of campylobacteriosis (i.e. enteritis), mice infected with the NCTC11168::cj0268c mutant strain displayed significant longer small as well as large intestinal lengths indicative for less distinct C. jejuni induced pathology when compared to infected control groups at day 6 p.i. This was further supported by significantly lower apoptotic and T cell numbers in the colonic mucosa and lamina propria, which were paralleled by lower intestinal IFN-c and IL-6 concentrations at day 6 following knockout mutant NCTC11168::cj0268c as compared to parental strain infection. Remarkably, less intestinal immunopathology was accompanied by lower IFN-c secretion in ex vivo biopsies taken from mesenteric lymphnodes of NCTC11168::cj0268c infected mice versus controls. Conclusion/Significance: We here for the first time show that the cj0268c gene is involved in mediating C. jejuni induced immunopathogenesis in vivo. Future studies will provide further deep insights into the immunological and molecular interplays between C. jejuni and innate immunity in human campylobacteriosis.
Microbiology, Jun 1, 2011
Campylobacter jejuni lacks the enzyme phosphofructokinase and, consequently, is incapable of meta... more Campylobacter jejuni lacks the enzyme phosphofructokinase and, consequently, is incapable of metabolizing glucose. Instead, the pathogen uses a number of other chemicals to serve as electron donors. Like chemolithotrophic bacteria, C. jejuni is able to respire sulphite in the presence of a sulphite : cytochrome c oxidoreductase (SOR) that is encoded by the genes cj0004c and cj0005c; the former encodes a monohaem cytochrome c oxidoreductase and the latter a molybdopterin oxidoreductase. After screening of a transposon-based mutant library, we identified a mutant with an insertion in gene cj0005c that was strongly reduced in its capacity to infect Caco2 cells. Further characterization of a corresponding non-random knockout mutant together with a complemented mutant and the parental strain showed the cj0005c-deficient mutant to exhibit clearly reduced motility and diminished adherence to host cells. Furthermore, the transcription of genes responsible for the synthesis of, in particular, legionaminic acid was downregulated and the mutant had a reduced capacity to autoagglutinate. In contrast, neither the proliferation of the mutant, nor its intracellular ATP content, was altered compared to the parental strain.
BMC Microbiology, 2012
Background: Campylobacter jejuni, the most leading cause for bacterial gastroenteritis worldwide,... more Background: Campylobacter jejuni, the most leading cause for bacterial gastroenteritis worldwide, shows a high genetic diversity among its isolates. Recently, we demonstrated the existence of six C. jejuni-groups by combining MLST with six genetic markers. These groups were further characterized by the detection of cj1321-cj1326, fucP, cj0178, cj0755/cfrA, ceuE, pldA, cstII, and cstIII in order (I.) to show further associations between these different genetic markers and MLST CCs. Moreover, different studies were able to associate several of these markers: a sialylated lipoologosaccharide (cstII/III +), the gamma-glytamyl-transpeptidase (ggt +), and the absence of a certain allele of the enterochelin-uptake-binding-protein (ceuE 11168-) with severe campylobacteriosis, bloody diarrhea and unpleasant outcome. Additionally more than half of human Campylobacter-isolates were assigned to a non-livestock clade associated with the absence of cj1321-cj1326. These isolates were considered as mere colonizers. From the combination of marker genes, the ratio of human isolates in a specific group, and clinical data (II.) it should be demonstrated to which of the previous defined groups these Campylobacter-subpopulations, associated with higher virulence, correspond. Results: Besides the marker gene pldA, all new estimated genetic markers show significant differences in their distribution among the various MLST-based groups. Especially the genes for cj1321-cj1326, fucP, cj0178, cj0755/cfrA are widely associated with each other and split the study population into two major and seven intermediate groups substantiating the previous group-definition, whereas cstII and cstIII indicate at least three groups following an independent distribution pattern. Conclusions: Based on these data a group of C. jejuni-isolates characterized by the presence of ansB, dmsA, ggt, and the absence of cj1365c, cj1585c, cj1321-cj1326, fucP, cj0178, cj0755/cfrA, and cstII/III was associated with a higher prevalence in human campylobacteriosis, bloody diarrhea as well as hospitalization and bears obviously a higher virulence for humans. In contrast to that better livestock-adapted groups characterized by the ability to utilize L-fucose and the presence of all of the five identified putative C. jejuni iron-uptake systems as well as cj1321-cj1326, cj1365c, cj1585c, and cstII and/or cstIII (sialylated lipoologosaccharide) is more prevalent in animal hosts and was secondary associated with less severe campylobacteriosis.
International Journal of Medical Microbiology, Apr 1, 2010
Campylobacter jejuni has long been recognized as a cause of bacterial food-borne illness, and sur... more Campylobacter jejuni has long been recognized as a cause of bacterial food-borne illness, and surprisingly, it remains the most prevalent bacterial food-borne pathogen in the industrial world to date. Natural reservoirs for this Gram-negative, spiral-shaped bacterium are wild birds, whose intestines offer a suitable biological niche for the survival and dissemination of C. jejuni Chickens become colonized shortly after birth and are the most important source for human infection. In the last decade, effective intervention strategies to limit infections caused by this elusive pathogen were hindered mainly because of a paucity in understanding the virulence mechanisms of C. jejuni and in part, unavailability of an adequate animal model for the disease. However, recent developments in deciphering molecular mechanisms of virulence of C. jejuni made it clear that C. jejuni is a unique pathogen, being able to execute N-linked glycosylation of more than 30 proteins related to colonization, adherence, and invasion. Moreover, the flagellum is not only depicted to facilitate motility but as well secretion of Campylobacter invasive antigens (Cia). The only toxin of C. jejuni, the so-called cytolethal distending toxin (CdtA,B,C), seems to be important for cell cycle control and induction of host cell apoptosis and has been recognized as a major pathogenicity-associated factor. In contrast to other diarrhoea-causing bacteria, no other classical virulence factors have yet been identified in C. jejuni. Instead, host factors seem to play a major role for pathogenesis of campylobacteriosis of man. Indeed, several lines of evidence suggest exploitation of different adaptation strategies by this pathogen depending on its requirement, whether to establish itself in the natural avian reservoir or during the course of human infection.
European journal of microbiology and immunology, Jun 1, 2016
Several studies have shown that about 60-100% of farmed ducks are colonized by Campylobacter spec... more Several studies have shown that about 60-100% of farmed ducks are colonized by Campylobacter species. Because of this, a higher risk of campylobacteriosis among duck farm workers can be assumed. To estimate the risk of Campylobacter infections in duck farm workers, we investigated the prevalence of Campylobacter spp. in ducks of two duck farms and the seroprevalence of anti-Campylobacter antibodies (IgA and IgG) in two cohorts of workers. The first cohort consisted of high-exposed stable workers and slaughterers, which was compared to a second cohort of non-/low-exposed persons. Duck caecal swabs and serum samples were collected in 2004, 2007, and 2010. The colonization rate in the examined ducks was found to be 80-90%. The seroprevalence of anti-Campylobacter IgA and IgG antibodies among the non-exposed cohort was found to be 0.00% in all 3 years. In contrast, the exposed cohort demonstrated an IgA
European journal of microbiology and immunology, Mar 1, 2011
Campylobacter spp. is the most common bacterial pathogen of gastroenteritis worldwide. Poultry is... more Campylobacter spp. is the most common bacterial pathogen of gastroenteritis worldwide. Poultry is the main reservoir and consequently the main origin of infections for humans. As a consequence of a primary Campylobacter infection which typically manifests as diarrhea, there is an increased risk to suffer from post-infectious complications such as reactive arthritis, neuropathia, myositis or a Guillain-Barré Syndrome. Usually the verification of acute campylobacteriosis is made by stool culture. In contrast, post-infectious complications can be diagnosed by serological assays. Since most of them are based on whole cell lysates, an insufficient specificity results from cross-reactions between related species. Therefore, the use of recombinant antigens becomes more and more favorable. Campylobacter is able to secrete a number of proteins, which are amongst others necessary for cell invasion and therefore play a crucial role for virulence. One of these, Cj0069, has a similar specificity and sensitivity in the detection of anti-Campylobacter jejuni IgG compared to the well-established antigens OMP18 and P39. This makes it a suitable antigen for diagnosing C. jejuni post-infectious complications.
Microbiology, Oct 1, 2010
Campylobacter jejuni, an important food-borne bacterial pathogen in industrialized countries and ... more Campylobacter jejuni, an important food-borne bacterial pathogen in industrialized countries and in the developing world, is one of the major causes of bacterial diarrhoea. To identify genes which are important for the invasion of host cells by the pathogen, we screened altogether 660 clones of a transposon-generated mutant library based on the clinical C. jejuni isolate B2. Thereby, we identified a clone with a transposon insertion in gene cj0952c. As in the well-characterized C. jejuni strain NCTC 11168, the corresponding protein together with the gene product of the adjacent gene cj0951c consists of two transmembrane domains, a HAMP domain and a putative MCP domain, which together are thought to act as a chemoreceptor, designated Tlp7. In this report we show that genes cj0952c and cj0951c (i) are important for the host cell invasion of the pathogen, (ii) are not translated as one protein in C. jejuni isolate B2, contradicting the idea of a postulated read-through mechanism, (iii) affect the motility of C. jejuni, (iv) alter the chemotactic behaviour of the pathogen towards formic acid, and (v) are not related to the utilization of formic acid by formate dehydrogenase.
Infection, Oct 14, 2008
Infections due to Actinomyces europaeus or Actinomyces turicensis have only rarely been reported.... more Infections due to Actinomyces europaeus or Actinomyces turicensis have only rarely been reported. We describe a case of chronic fistulae caused by a coinfection with A. europaeus and A. turicensis in an immunocompetent male patient with a severe congenital femur hypoplasia. Actinomycosis is most probably the consequence of a postoperative wound infection after a prior surgical intervention. Both Actinomyces species were identified by 16S rRNA gene sequencing. The Actinomycescaused fistulae were treated by excision and a 1-week course of i.v. vancomycin followed by a 1-week course of p.o. cefuroxime.
Journal of Microbiological Methods, Aug 1, 2018
Two new DNA FISH-probes for Campylobacter fetus were designed, in silico checked for cross-reacti... more Two new DNA FISH-probes for Campylobacter fetus were designed, in silico checked for cross-reactions and successfully evaluated in a multi-centric approach with 41 Campylobacter fetus isolates including isolates of all three know subspecies: Campylobacter fetus ssp. fetus, Campylobacter fetus ssp. venerealis, and Campylobacter fetus ssp. testudinum and 40 strains of five non-target Campylobacter species.
BMC Microbiology, Sep 10, 2018
Background: Campylobacter jejuni is one of the most common bacterial causes of food-borne enterit... more Background: Campylobacter jejuni is one of the most common bacterial causes of food-borne enteritis worldwide. Chemotaxis in C. jejuni is known to be critical for the successful colonization of the host and key for the adaptation of the microbial species to different host environments. In C. jejuni, chemotaxis is regulated by a complex interplay of 13 or even more different chemoreceptors, also known as transducer-like proteins (Tlps). Recently, a novel chemoreceptor gene, tlp12, was described and found to be present in 29.5% of the investigated C. jejuni strains. Results: In this study, we present a functional analysis of Tlp12 with the aid of a tlp12 knockout mutant of the C. jejuni strain A17. Substrate specificity was investigated by capillary chemotaxis assays and revealed that Tlp12 plays an important role in chemotaxis towards glutamate and pyruvate. Moreover, the Δtlp12 mutant shows increased swarming motility in soft agar assays, an enhanced invasion rate into Caco-2 cells and an increased autoagglutination rate. The growth rate was slightly reduced in the Δtlp12 mutant. The identified phenotypes were in partial restored by complementation with the wild type gene. Tlp12-harboring C. jejuni strains display a strong association with chicken, whose excreta are known to contain high glutamate levels. Conclusions: TLP12 is a chemoreceptor for glutamate and pyruvate recognition. Deletion of tlp12 has an influence on distinct physiological features, such as growth rate, swarming motility, autoagglutination and invasiveness.
Proteomics Clinical Applications, Oct 11, 2018
Purpose: Bile acids are crucial components of the intestinal antimicrobial defense and represent ... more Purpose: Bile acids are crucial components of the intestinal antimicrobial defense and represent a significant stress factor for enteric pathogens. Adaptation processes of Campylobacter jejuni to this hostile environment are analyzed in this study by a proteomic approach. Experimental design: Proteome profiling by label-free mass spectrometry (SWATH-MS) has been used to characterize the adaptation of C. jejuni to sublethal concentrations of seven bile acids. Results: The bile acids with the lowest inhibitory concentration (IC 50), deoxycholic and chenodeoxycholic acid, induce the most significant proteome changes. Overall a downregulation of all basic biosynthetic pathways and a general decrease in the transcription machinery are found. Concurrently, an induction of factors involved in detoxification of reactive oxygen species, protein folding, and bile acid exporting efflux pumps is detected. Exposure to deoxycholic and chenodeoxycholic acid results in an increased expression of components of the more energy-efficient aerobic respiration pathway, while the anaerobic branches of the electron transport chain are down-expressed. Conclusions and clinical relevance: The results show that C. jejuni has a differentiated system of adaptation to bile acid stresses. The findings enhance the understanding of the pathogenesis of campylobacteriosis, especially for survival of C. jejuni in the human intestine, and may provide clues to future medical treatment.
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Papers by Andreas Zautner