scholarly journals Genomic Analysis of Chilean Strains of Campylobacter jejuni from Human Faeces

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Arturo Levican ◽  
Ignacio Ramos-Tapia ◽  
Isabel Briceño ◽  
Francisco Guerra ◽  
Benjamin Mena ◽  
...  
Keyword(s):  
Latin American ◽  
Bacterial Species ◽  
Bacterial Pathogen ◽  
Acute Diarrhoea ◽  
Genomic Analysis ◽  
Relevant Information ◽  
Human Infection ◽  
Secretion Systems ◽  
Association Analyses ◽  
Type Iv

Campylobacter spp., especially C. jejuni, are recognized worldwide as the bacterial species that most commonly cause food-related diarrhea. C. jejuni possesses many different virulence factors, has the ability to survive in different reservoirs, and has shown among isolates the emergence of Antimicrobial Resistance (AMR). Genome association analyses of this bacterial pathogen have contributed to a better understanding of its pathogenic and AMR associated determinants. However, the epidemiological information of these bacteria in Latin American countries is scarce and no genomic information is available in public databases from isolates in these countries. Considering this, the present study is aimed to describe the genomic traits from representative Campylobacter spp. strains recovered from faecal samples of patients with acute diarrhoea from Valparaíso, Chile. Campylobacter spp. was detected from the faeces of 28 (8%) out of 350 patients with acute diarrhoea, mainly from young adults and children, and 26 (93%) of the isolates corresponded to C. jejuni. 63% of the isolates were resistant to ciprofloxacin, 25.9% to tetracycline, and 3.5% to erythromycin. Three isolates were selected for WGS on the basis of their flaA-RFLP genotype. They belonged to the multilocus sequence typing (MLST) clonal clomplex (CC) 21(PUCV-1), CC-48 (PUCV-3), and CC-353 (PUCV-2) and presented several putative virulence genes, including the Type IV and Type VI Secretion Systems, as well as AMR-associated genes in agreement with their susceptibility pattern. On the basis of the wgMLST, they were linked to strains from poultry and ruminants. These are the first genomes of Chilean C. jejuni isolates available in public databases and they provide relevant information about the C. jejuni isolates associated with human infection in this country.

scholarly journals Moraxella catarrhalis: from Emerging to Established Pathogen

2002 ◽  
Vol 15 (1) ◽  
pp. 125-144 ◽  
Author(s):  
Cees M. Verduin ◽  
Cees Hol ◽  
André Fleer ◽  
Hans van Dijk ◽  
Alex van Belkum
Keyword(s):  
Moraxella Catarrhalis ◽  
Current Knowledge ◽  
Bacterial Species ◽  
Bacterial Pathogen ◽  
Diagnostic Techniques ◽  
Human Infection ◽  
Molecular Diagnostic ◽  
Molecular Diagnostic Techniques ◽  
Pathogenic Potential ◽  
The Past

SUMMARY Moraxella catarrhalis (formerly known as Branhamella catarrhalis) has emerged as a significant bacterial pathogen of humans over the past two decades. During this period, microbiological and molecular diagnostic techniques have been developed and improved for M. catarrhalis, allowing the adequate determination and taxonomic positioning of this pathogen. Over the same period, studies have revealed its involvement in respiratory (e.g., sinusitis, otitis media, bronchitis, and pneumonia) and ocular infections in children and in laryngitis, bronchitis, and pneumonia in adults. The development of (molecular) epidemiological tools has enabled the national and international distribution of M. catarrhalis strains to be established, and has allowed the monitoring of nosocomial infections and the dynamics of carriage. Indeed, such monitoring has revealed an increasing number of Β-lactamase-positive M. catarrhalis isolates (now well above 90%), underscoring the pathogenic potential of this organism. Although a number of putative M. catarrhalis virulence factors have been identified and described in detail, their relationship to actual bacterial adhesion, invasion, complement resistance, etc. (and ultimately their role in infection and immunity), has been established in a only few cases. In the past 10 years, various animal models for the study of M. catarrhalis pathogenicity have been described, although not all of these models are equally suitable for the study of human infection. Techniques involving the molecular manipulation of M. catarrhalis genes and antigens are also advancing our knowledge of the host response to and pathogenesis of this bacterial species in humans, as well as providing insights into possible vaccine candidates. This review aims to outline our current knowledge of M. catarrhalis, an organism that has evolved from an emerging to a well-established human pathogen.

scholarly journals T4SP Database 2.0: An Improved Database for Type IV Secretion Systems in Bacterial Genomes with New Online Analysis Tools

2016 ◽  
Vol 2016 ◽  
pp. 1-4 ◽  
Author(s):  
Na Han ◽  
Weiwen Yu ◽  
Yujun Qiang ◽  
Wen Zhang
Keyword(s):  
Recipient Cell ◽  
Bacterial Species ◽  
Genetic Material ◽  
Type Iv Secretion ◽  
Bacterial Strains ◽  
Secretion Systems ◽  
Bacterial Genomes ◽  
Type Iv ◽  
Type Iv Secretion Systems ◽  
User Friendly

Type IV secretion system (T4SS) can mediate the passage of macromolecules across cellular membranes and is essential for virulent and genetic material exchange among bacterial species. The Type IV Secretion Project 2.0 (T4SP 2.0) database is an improved and extended version of the platform released in 2013 aimed at assisting with the detection of Type IV secretion systems (T4SS) in bacterial genomes. This advanced version provides users with web server tools for detecting the existence and variations of T4SS genes online. The new interface for the genome browser provides a user-friendly access to the most complete and accurate resource of T4SS gene information (e.g., gene number, name, type, position, sequence, related articles, and quick links to other webs). Currently, this online database includes T4SS information of 5239 bacterial strains.Conclusions. T4SS is one of the most versatile secretion systems necessary for the virulence and survival of bacteria and the secretion of protein and/or DNA substrates from a donor to a recipient cell. This database on virB/D genes of the T4SS system will help scientists worldwide to improve their knowledge on secretion systems and also identify potential pathogenic mechanisms of various microbial species.

scholarly journals Molecular and Structural Analysis of the Helicobacter pylori cag Type IV Secretion System Core Complex

mBio ◽  
2016 ◽  
Vol 7 (1) ◽  
Author(s):  
Arwen E. Frick-Cheng ◽  
Tasia M. Pyburn ◽  
Bradley J. Voss ◽  
W. Hayes McDonald ◽  
Melanie D. Ohi ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Bacterial Species ◽  
Secretion System ◽  
Effector Proteins ◽  
Type Iv Secretion ◽  
Secretion Systems ◽  
Core Complex ◽  
Type Iv ◽  
Membrane Spanning ◽  
H Pylori

ABSTRACT Bacterial type IV secretion systems (T4SSs) can function to export or import DNA, and can deliver effector proteins into a wide range of target cells. Relatively little is known about the structural organization of T4SSs that secrete effector proteins. In this report, we describe the isolation and analysis of a membrane-spanning core complex from the Helicobacter pylori cag T4SS, which has an important role in the pathogenesis of gastric cancer. We show that this complex contains five H. pylori proteins, CagM, CagT, Cag3, CagX, and CagY, each of which is required for cag T4SS activity. CagX and CagY are orthologous to the VirB9 and VirB10 components of T4SSs in other bacterial species, and the other three Cag proteins are unique to H. pylori . Negative stain single-particle electron microscopy revealed complexes 41 nm in diameter, characterized by a 19-nm-diameter central ring linked to an outer ring by spoke-like linkers. Incomplete complexes formed by Δ cag3 or Δ cagT mutants retain the 19-nm-diameter ring but lack an organized outer ring. Immunogold labeling studies confirm that Cag3 is a peripheral component of the complex. The cag T4SS core complex has an overall diameter and structural organization that differ considerably from the corresponding features of conjugative T4SSs. These results highlight specialized features of the H. pylori cag T4SS that are optimized for function in the human gastric mucosal environment. IMPORTANCE Type IV secretion systems (T4SSs) are versatile macromolecular machines that are present in many bacterial species. In this study, we investigated a T4SS found in the bacterium Helicobacter pylori. H. pylori is an important cause of stomach cancer, and the H. pylori T4SS contributes to cancer pathogenesis by mediating entry of CagA (an effector protein regarded as a “bacterial oncoprotein”) into gastric epithelial cells. We isolated and analyzed the membrane-spanning core complex of the H. pylori T4SS and showed that it contains unique proteins unrelated to components of T4SSs in other bacterial species. These results constitute the first structural analysis of the core complex from this important secretion system.

scholarly journals Natural Transformation of Campylobacter jejuni Requires Components of a Type II Secretion System

2003 ◽  
Vol 185 (18) ◽  
pp. 5408-5418 ◽  
Author(s):  
Rebecca S. Wiesner ◽  
David R. Hendrixson ◽  
Victor J. DiRita
Keyword(s):  
Campylobacter Jejuni ◽  
Natural Transformation ◽  
Bacterial Species ◽  
Type Ii Secretion ◽  
Dna Uptake ◽  
Type Ii ◽  
Secretion Systems ◽  
Dna Transport ◽  
Type Iv ◽  
Type Ii Secretion System

ABSTRACT The human pathogen Campylobacter jejuni is one of more than 40 naturally competent bacterial species able to import macromolecular DNA from the environment and incorporate it into their genomes. However, in C. jejuni little is known about the genes involved in this process. We used random transposon mutagenesis to identify genes that are required for the transformation of this organism. We isolated mutants with insertions in 11 different genes; most of the mutants are affected in the DNA uptake stage of transformation, whereas two mutants are affected in steps subsequent to DNA uptake, such as recombination into the chromosome or in DNA transport across the inner membrane. Several of these genes encode proteins homologous to those involved in type II secretion systems, biogenesis of type IV pili, and competence for natural transformation in gram-positive and gram-negative species. Other genes identified in our screen encode proteins unique to C. jejuni or are homologous to proteins that have not been shown to play a role in the transformation in other bacteria.

scholarly journals Oxygen depletion and nitric oxide stimulate type IV MSHA pilus retraction in Vibrio cholerae via activation of the phosphodiesterase CdpA

2021 ◽  
Author(s):  
Hannah Q Hughes ◽  
Kyle A Floyd ◽  
Sajjad Hossain ◽  
Sweta Anantharaman ◽  
David T Kysela ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Vibrio Cholerae ◽  
Biofilm Formation ◽  
Bacterial Species ◽  
Bacterial Pathogen ◽  
Dna Uptake ◽  
Dynamic Activity ◽  
Regulatory Pathways ◽  
Type Iv ◽  
Microaerobic Conditions

Bacteria use surface appendages called type IV pili to perform diverse activities including DNA uptake, twitching motility, and attachment to surfaces. Dynamic extension and retraction of pili is often required for these activities, but the stimuli that regulate these dynamics remain poorly characterized. To study this question, we use the bacterial pathogen Vibrio cholerae, which uses mannose-sensitive hemagglutinin (MSHA) pili to attach to surfaces in aquatic environments as the first step in biofilm formation. Here, we find that V. cholerae cells retract MSHA pili and detach from a surface in microaerobic conditions. This response is dependent on the phosphodiesterase CdpA, which decreases intracellular levels of cyclic-di-GMP (c-di-GMP) under microaerobic conditions to induce MSHA pilus retraction. CdpA contains a putative NO-sensing NosP domain, and we demonstrate that nitric oxide (NO) is necessary and sufficient to stimulate CdpA-dependent detachment. Thus, we hypothesize that microaerobic conditions result in endogenous production of NO (or an NO-like molecule) in V. cholerae. Together, these results describe a regulatory pathway that allows V. cholerae to rapidly abort biofilm formation. More broadly, these results show how environmental cues can be integrated into the complex regulatory pathways that control pilus dynamic activity and attachment in bacterial species.

scholarly journals Large scale genomic analysis shows no evidence for repeated pathogen adaptation during the invasive phase of bacterial meningitis in humans

2016 ◽  
Author(s):  
John A. Lees ◽  
Philip H.C. Kremer ◽  
Ana S. Manso ◽  
Nicholas J. Croucher ◽  
Bart Ferwerda ◽  
...  
Keyword(s):  
Cerebrospinal Fluid ◽  
Bacterial Meningitis ◽  
Large Scale ◽  
Single Case ◽  
Bacterial Species ◽  
Bacterial Pathogen ◽  
Variant Calling ◽  
Genomic Analysis ◽  
Single Patient ◽  
Paired Samples

AbstractRecent studies have provided evidence for rapid pathogen genome variation, some of which could potentially affect the course of disease. We have previously detected such variation by comparing isolates infecting the blood and cerebrospinal fluid (CSF) of a single patient during a case of bacterial meningitis.To determine whether the observed variation repeatedly occurs in cases of disease, we performed whole genome sequencing of paired isolates from blood and CSF of 938 meningitis patients. We also applied the same techniques to 54 paired isolates from the nasopharynx and CSF.Using a combination of reference-free variant calling approaches we show that no genetic adaptation occurs in the invasive phase of bacterial meningitis for four major pathogen species:Streptococcus pneumoniae, Neisseria meningitidis, Listeria monocytogenes and Haemophilus influenzae. From nasopharynx to CSF, no adaptation was seen inS. pneumoniae, but inN. meningitidismutations potentially mediating adaptation to the invasive niche were occasionally observed in thedcagene.This study therefore shows that the bacteria capable of causing meningitis are already able to do this upon entering the blood, and no further sequence change is necessary to cross the blood-brain barrier. The variation discovered from nasopharyngeal isolates suggest that larger studies comparing carriage and invasion may help determine the likely mechanisms of invasiveness.Author SummaryWe have analysed the entire DNA sequence from bacterial pathogen isolates from cases of meningitis in 938 Dutch adults, focusing on comparing pairs of isolates from the patient’s blood and their cerebrospinal fluid. Previous research has been on only a single patient, but showed possible signs of adaptation to treatment within the host over the course of a single case of disease.By sequencing many more such paired samples, and including four different bacterial species, we were able to determine that adaptation of the pathogen does not occur after bloodstream invasion during bacterial meningitis.We also analysed 54 pairs of isolates from pre- and post-invasive niches from the same patient. InN. meningitidiswe found variation in the sequence of one gene which appears to provide bacteria with an advantage after invasion of the bloodstream.Overall, our findings indicate that evolution after invasion in bacterial meningitis is not a major contribution to disease pathogenesis. Future studies should involve more extensive sampling between the carriage and disease niches, or on variation of the host.

scholarly journals Construction of a complete set of Neisseria meningitidis defined mutants – the NeMeSys 2.0 collection – and its use for the phenotypic profiling of the genome of an important human pathogen

2020 ◽  
Author(s):  
Alastair Muir ◽  
Ishwori Gurung ◽  
Ana Cehovin ◽  
Adelme Bazin ◽  
David Vallenet ◽  
...  
Keyword(s):  
Neisseria Meningitidis ◽  
Bacterial Species ◽  
Bacterial Pathogen ◽  
Essential Genes ◽  
Human Pathogen ◽  
Gene Encoding ◽  
Complete Collection ◽  
Protein Coding ◽  
Type Iv ◽  
Genome Information

AbstractOne of the great challenges in biology is to determine the function of millions of genes of unknown function. Even in model bacterial species, there is a sizeable proportion of such genes, which has fundamental and practical consequences. Here, we constructed a complete collection of defined mutants in protein-coding genes – named NeMeSys 2.0 – in the human pathogen Neisseria meningitidis, consisting of individual mutants in 1,584 non-essential genes. This effort identified 391 essential genes – broadly conserved in other bacteria – leading to a full overview of the essential meningococcal genome, associated with just four underlying basic biological functions: 1) expression of genome information, 2) preservation of genome information, 3) cell membrane structure/function, and 4) cytosolic metabolism. Subsequently, we illustrated the utility of the NeMeSys 2.0 collection for determining gene function by identifying 1) a novel and conserved family of histidinol-phosphatase, 2) 20 genes, including three new ones, involved in the biology of type IV pili, a widespread virulence factor, and 3) several conditionally essential genes found in regions of genome plasticity encoding antitoxins and/or immunity proteins, which become dispensable when the gene encoding the cognate toxin is deleted. These findings have implications beyond the meningococcus. The NeMeSys 2.0 collection is an invaluable resource paving the way for a global phenotypic landscape in a major human bacterial pathogen.

scholarly journals Transfer of DNA from Bacteria to Eukaryotes

mBio ◽  
2016 ◽  
Vol 7 (4) ◽  
Author(s):  
Benoît Lacroix ◽  
Vitaly Citovsky
Keyword(s):  
Bartonella Henselae ◽  
Bacterial Species ◽  
Symbiotic Bacterium ◽  
Host Cells ◽  
Conjugative Plasmid ◽  
Secretion Systems ◽  
Type Iv ◽  
Conjugative Plasmid Transfer ◽  
Eukaryotic Species ◽  
Potential Applications

ABSTRACTHistorically, the members of theAgrobacteriumgenus have been considered the only bacterial species naturally able to transfer and integrate DNA into the genomes of their eukaryotic hosts. Yet, increasing evidence suggests that this ability to genetically transform eukaryotic host cells might be more widespread in the bacterial world. Indeed, analyses of accumulating genomic data reveal cases of horizontal gene transfer from bacteria to eukaryotes and suggest that it represents a significant force in adaptive evolution of eukaryotic species. Specifically, recent reports indicate that bacteria other thanAgrobacterium, such asBartonella henselae(a zoonotic pathogen),Rhizobium etli(a plant-symbiotic bacterium related toAgrobacterium), or evenEscherichia coli, have the ability to genetically transform their host cells under laboratory conditions. This DNA transfer relies on type IV secretion systems (T4SSs), the molecular machines that transport macromolecules during conjugative plasmid transfer and also during transport of proteins and/or DNA to the eukaryotic recipient cells. In this review article, we explore the extent of possible transfer of genetic information from bacteria to eukaryotic cells as well as the evolutionary implications and potential applications of this transfer.

scholarly journals Comparative Genomic Analysis of the pPT23A Plasmid Family of Pseudomonas syringae

2005 ◽  
Vol 187 (6) ◽  
pp. 2113-2126 ◽  
Author(s):  
Youfu Zhao ◽  
Zhonghua Ma ◽  
George W. Sundin
Keyword(s):  
Pseudomonas Syringae ◽  
Bacterial Pathogen ◽  
Genomic Analysis ◽  
Complete Sequence ◽  
Secretion System ◽  
Comparative Genomic ◽  
Type Iv ◽  
Gene Acquisition ◽  
Genes Encoding ◽  
Type Ivb Secretion

ABSTRACT Members of the pPT23A plasmid family of Pseudomonas syringae play an important role in the interaction of this bacterial pathogen with host plants. Complete sequence analysis of several pPT23A family plasmids (PFPs) has provided a glimpse of the gene content and virulence function of these plasmids. We constructed a macroarray containing 161 genes to estimate and compare the gene contents of 23 newly analyzed and eight known PFPs from 12 pathovars of P. syringae, which belong to four genomospecies. Hybridization results revealed that PFPs could be distinguished by the type IV secretion system (T4SS) encoded and separated into four groups. Twelve PFPs along with pPSR1 from P. syringae pv. syringae, pPh1448B from P. syringae pv. phaseolicola, and pPMA4326A from P. syringae pv. maculicola encoded a type IVA T4SS (VirB-VirD4 conjugative system), whereas 10 PFPs along with pDC3000A and pDC3000B from P. syringae pv. tomato encoded a type IVB T4SS (tra system). Two plasmids encoded both T4SSs, whereas six other plasmids carried none or only a few genes of either the type IVA or type IVB secretion system. Most PFPs hybridized to more than one putative type III secretion system effector gene and to a variety of additional genes encoding known P. syringae virulence factors. The overall gene contents of individual PFPs were more similar among plasmids within each of the four groups based on T4SS genes; however, a number of genes, encoding plasmid-specific functions or hypothetical proteins, were shared among plasmids from different T4SS groups. The only gene shared by all PFPs in this study was the repA gene, which encoded sequences with 87 to 99% amino acid identityamong 25 sequences examined. We proposed a model to illustrate the evolution and gene acquisition of the pPT23A plasmid family. To our knowledge, this is the first such attempt to conduct a global genetic analysis of this important plasmid family.

scholarly journals Type IV pili share a conserved mechanism of motor-independent retraction that is an inherent property of the pilus filament

2021 ◽  
Author(s):  
Jennifer L. Chlebek ◽  
Lisa Craig ◽  
Ankur B. Dalia
Keyword(s):  
Bacterial Pathogens ◽  
Bacterial Species ◽  
Type Iv Pili ◽  
Secretion Systems ◽  
Acinetobacter Baylyi ◽  
Dynamic Activity ◽  
Dynamic Surface ◽  
Inherent Property ◽  
Type Iv ◽  
Pilin Gene

ABSTRACTType IV pili (T4P) are dynamic surface appendages that promote virulence, biofilm formation, horizontal gene transfer, and motility in diverse bacterial species. Pilus dynamic activity is best characterized in T4P that use distinct ATPase motors for pilus extension and retraction. Many T4P systems, however, lack a dedicated retraction motor and the mechanism underlying this motor-independent retraction remains a mystery. Using the Vibrio cholerae competence pilus as a model system, we identify mutations in the major pilin gene that enhance motor-independent retraction. These mutants produced less stable pili, likely due to diminished pilin-pilin interactions within the filament. One mutation adds a bulky residue to α1C, a universally conserved feature of type IV pilins. We found that inserting a bulky residue into α1C of the retraction motor-dependent Acinetobacter baylyi com-petence T4P is sufficient to induce motor-independent retraction. Conversely, removing bulky residues from α1C of the retraction motor-independent V. cholerae toxin-co-regulated T4P stabilizes the filament and prevents retraction. Furthermore, alignment of pilins from the broader type IV filament (T4F) family indicated that retraction motor-independent T4P, Com pili, and type II secretion systems generally encode larger residues within α1C oriented toward the pilus core compared to retraction motor-dependent T4P. Together, our data demonstrate that motor-independent retraction relies on the inherent instability of the pilus filament that may be conserved in diverse T4Fs. This provides the first evidence for a long-standing, yet untested, model in which pili retract in the absence of a motor by spontaneous de-polymerization.SIGNIFICANCEExtracellular pilus filaments are critical for the virulence and persistence of many bacterial pathogens. A crucial property of these filaments is their ability to dynamically extend and retract from the bacterial surface. A detailed mechanistic understanding of pilus retraction, however, remains lacking in many systems. Here, we reveal that pilus retraction is an inherent property of the pilus filament. These observations are broadly relevant to diverse pilus systems, including those in many bacterial pathogens, and may help inform novel therapeutic strategies that aim to target pilus dynamic activity.

Sign in / Sign up

Export Citation Format

Share Document