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Infectious Diseases Now Jun 2022We report for the first time the association of Haemophilus pittmaniae and Haemophilus sputorum with urethritis in men who have sex with men and who engage in...
BACKGROUND
We report for the first time the association of Haemophilus pittmaniae and Haemophilus sputorum with urethritis in men who have sex with men and who engage in unprotected intercourse.
PATIENTS AND METHODS
A search for genital pathogens was conducted using urethral exudate cultures and PCR tests for Chlamydia trachomatis, Neisseria gonorrhoeae, Trichomonas vaginalis, Mycoplasma spp., and Ureaplasma spp. Recovered microorganisms were identified by MALDI-TOF mass spectrometry, and their susceptibility was evaluated by diffusion gradient test.
RESULTS
H. pittmaniae and H. sputorum were isolated. They both proved susceptible to ampicillin, cefixime, and trimethoprim/sulfamethoxazole. H. pittmaniae was also susceptible to tetracycline and H. sputorum to moxifloxacin.
CONCLUSION
The increased frequency of potentially resistant Haemophilus spp. isolates in genital exudates highlights the need for greater surveillance of these microorganisms and for their consideration in the differential diagnosis of genital system infections.
Topics: Genitalia; Haemophilus; Homosexuality, Male; Humans; Male; Sexual and Gender Minorities; Urinary Tract Infections
PubMed: 35483632
DOI: 10.1016/j.idnow.2022.04.003 -
Microbiological Research Jan 2015Bacterial secretion systems, such as type IV secretion systems (T4SSs) are multi-subunit machines transferring macromolecules across membranes. Besides proteins, T4SSs... (Review)
Review
Bacterial secretion systems, such as type IV secretion systems (T4SSs) are multi-subunit machines transferring macromolecules across membranes. Besides proteins, T4SSs also transfer nucleoprotein complexes, thus having a significant impact on the evolution of bacterial species. By T4SS-mediated horizontal gene transfer bacteria can acquire a broad spectrum of fitness genes allowing them to thrive in the wide variety of environments. Furthermore, acquisition of antibiotic-resistance and virulence genes can lead to the emergence of novel 'superbugs'. This review provides an update on the investigation of T4SSs. It highlights the role T4SSs play in the horizontal gene transfer, particularly in the evolution of catabolic pathways, antibiotic-resistance and virulence in Haemophilus and Pseudomonas.
Topics: Bacterial Secretion Systems; Drug Resistance, Neoplasm; Gene Transfer, Horizontal; Genomic Islands; Haemophilus; Pseudomonas
PubMed: 25183653
DOI: 10.1016/j.micres.2014.06.007 -
Nature Communications Sep 2023Soluble HMW1C-like N-glycosyltransferases (NGTs) catalyze the glycosylation of Asn residues in proteins, a process fundamental for bacterial autoaggregation, adhesion...
Soluble HMW1C-like N-glycosyltransferases (NGTs) catalyze the glycosylation of Asn residues in proteins, a process fundamental for bacterial autoaggregation, adhesion and pathogenicity. However, our understanding of their molecular mechanisms is hindered by the lack of structures of enzymatic complexes. Here, we report structures of binary and ternary NGT complexes of Aggregatibacter aphrophilus NGT (AaNGT), revealing an essential dyad of basic/acidic residues located in the N-terminal all α-domain (AAD) that intimately recognizes the Thr residue within the conserved motif Asn-X-Ser/Thr. Poor substrates and inhibitors such as UDP-galactose and UDP-glucose mimetics adopt non-productive conformations, decreasing or impeding catalysis. QM/MM simulations rationalize these results, showing that AaNGT follows a S2 reaction mechanism in which the acceptor asparagine uses its imidic form for catalysis and the UDP-glucose phosphate group acts as a general base. These findings provide key insights into the mechanism of NGTs and will facilitate the design of structure-based inhibitors to treat diseases caused by non-typeable H. influenzae or other Gram-negative bacteria.
Topics: Glycosylation; Bacterial Proteins; Asparagine; Haemophilus influenzae; Glucose; Uridine Diphosphate
PubMed: 37723184
DOI: 10.1038/s41467-023-41238-1 -
MBio Mar 2021Like the bacterial residents of the human gut, it is likely that many of the species in the human oral microbiota have evolved to better occupy and persist in their...
Like the bacterial residents of the human gut, it is likely that many of the species in the human oral microbiota have evolved to better occupy and persist in their niche. () is both a common colonizer of the oral cavity and has been implicated in the pathogenesis of periodontal disease. Here, we present a whole-genome phylogenetic analysis of isolates from humans and nonhuman primates that revealed an ancient origin for this species and a long history of association with the , the lineage that includes Old World monkeys (OWM) and humans. Further genomic analysis showed a strong association with the presence of a short-chain fatty acid (SCFA) catabolism locus () in many human isolates that was absent in almost all nonhuman OWM isolates. We show that this locus was likely acquired through horizontal gene transfer. When grown under conditions that are similar to those at the subgingival site of periodontitis (anaerobic, SCFA replete), strains with formed robust biofilms and showed upregulation of genes involved in virulence, colonization, and immune evasion. Both an isogenic deletion mutant and nonhuman primate isolates lacking the locus failed to grow in a robust biofilm under these conditions, but grew well under the carbohydrate-rich conditions similar to those found above the gumline. We propose that the acquisition of the locus was a key evolutionary step allowing to utilize SCFAs, adapt, and modulate subgingival disease. There has been considerable interest in the impact of short-chain fatty acids (SCFAs) on inflammatory effects related to the microbiome. Here, we present evidence that SCFAs may also be important in disease by providing an energy source or disease-associated cue for colonizing pathogens. We propose that SCFAs allow () to adapt to the subgingival anaerobic environment, which is the site of human periodontitis. Under anaerobic, SCFA-rich conditions, human-derived strains that possess butyrate metabolism genes form strong biofilms and upregulate virulence genes. Our phylogenetic analysis highlights a long history of evolution of with its primate hosts and suggests that the acquisition of butyrate metabolism genes may have been a critical step in allowing to colonize a new niche and cause disease in humans. Overall, this study highlights the important role that horizontal gene transfer may play in microbial adaptation and the evolution of infectious disease.
Topics: Adaptation, Physiological; Aggregatibacter actinomycetemcomitans; Anaerobiosis; Biofilms; Butyrates; Gene Transfer, Horizontal; Genome, Bacterial; Time Factors
PubMed: 33758084
DOI: 10.1128/mBio.03581-20 -
Scientific Reports Aug 2020Pulmonary infection is associated with inflammation and damage to the bronchial epithelium characterized by an increase in the release of inflammatory factors and a...
Pulmonary infection is associated with inflammation and damage to the bronchial epithelium characterized by an increase in the release of inflammatory factors and a decrease in airway barrier function. Our objective is to optimize a method for the isolation and culture of primary bronchial epithelial cells (PBECs) and to provide an ex vivo model to study mechanisms of epithelial airway inflammation. PBECs were isolated and cultured from the airways of calves in a submerged cell culture and liquid-liquid interface system. A higher yield and cell viability were obtained after stripping the epithelium from the bronchial section compared to cutting the bronchial section in smaller pieces prior to digestion. Mannheimia haemolytica and lipopolysaccharide (LPS) as stimulants increased inflammatory responses (IL-8, IL-6 and TNF-α release), possibly, by the activation of "TLR-mediated MAPKs and NF-κB" signaling. Furthermore, M. haemolytica and LPS disrupted the bronchial epithelial layer as observed by a decreased transepithelial electrical resistance and zonula occludens-1 and E-cadherin expression. An optimized isolation and culture method for calf PBECs was developed, which cooperated with animal use Replacement, Reduction and Refinement (3R's) principle, and can also contribute to the increased knowledge and development of effective therapies for other animal and humans (childhood) respiratory diseases.
Topics: Animals; Bronchi; Cattle; Cells, Cultured; Cytokines; Disease Models, Animal; Epithelial Cells; Inflammation; Lipopolysaccharides; Lung; Mannheimia haemolytica; Models, Biological; Pasteurellaceae Infections
PubMed: 32747652
DOI: 10.1038/s41598-020-69982-0 -
The Journal of Pharmacy and Pharmacology Mar 2021We and others have previously shown that epigallocatechin gallate (EGCg) inhibits the activity of an important virulence factor, leukotoxin (LtxA), produced by the oral...
OBJECTIVES
We and others have previously shown that epigallocatechin gallate (EGCg) inhibits the activity of an important virulence factor, leukotoxin (LtxA), produced by the oral bacterium Aggregatibacter actinomycetemcomitans, suggesting the potential use of this molecule as an anti-virulence strategy to treat periodontal infections. Here, we sought to better understand the effects of EGCg on toxin secretion and A. actinomycetemcomitans pathogenicity in a co-culture model.
METHODS
We used a quantitative immunoblot assay to determine the concentrations of LtxA in the bacterial supernatant and on the bacterial cell surface. Using a co-culture model, consisting of A. actinomycetemcomitans and THP-1 cells, we studied the impact of EGCg-mediated changes in LtxA secretion on the toxicity of A. actinomycetemcomitans.
KEY FINDINGS
EGCg increased production of LtxA and changed the localization of secreted LtxA from the supernatant to the surface of the bacterial cells. In the co-culture model, a single low dose of EGCg did not protect host THP-1 cells from A. actinomycetemcomitans-mediated cytotoxicity, but a multiple dosing strategy had improved effects.
CONCLUSIONS
Together, these results demonstrate that EGCg has important, but complicated, effects on toxin secretion and activity; new dosing strategies and comprehensive model systems may be required to properly develop these anti-virulence activities.
Topics: Aggregatibacter actinomycetemcomitans; Anti-Bacterial Agents; Bacterial Toxins; Catechin; Coculture Techniques; Dose-Response Relationship, Drug; Exotoxins; Humans; Periodontitis; Virulence
PubMed: 33793838
DOI: 10.1093/jpp/rgaa051 -
Emerging Infectious Diseases Mar 2018Encapsulated Haemophilus influenzae strains belong to type-specific genetic lineages. Reliable capsule typing requires PCR, but a more efficient method would be useful....
Encapsulated Haemophilus influenzae strains belong to type-specific genetic lineages. Reliable capsule typing requires PCR, but a more efficient method would be useful. We evaluated capsule typing by using matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry. Isolates of all capsule types (a-f and nontypeable; n = 258) and isogenic capsule transformants (types a-d) were investigated. Principal component and biomarker analyses of mass spectra showed clustering, and mass peaks correlated with capsule type-specific genetic lineages. We used 31 selected isolates to construct a capsule typing database. Validation with the remaining isolates (n = 227) showed 100% sensitivity and 92.2% specificity for encapsulated strains (a-f; n = 61). Blinded validation of a supplemented database (n = 50) using clinical isolates (n = 126) showed 100% sensitivity and 100% specificity for encapsulated strains (b, e, and f; n = 28). MALDI-TOF mass spectrometry is an accurate method for capsule typing of H. influenzae.
Topics: Bacterial Capsules; Bacterial Typing Techniques; Evolution, Molecular; Genetic Linkage; Haemophilus Infections; Haemophilus influenzae; Multilocus Sequence Typing; Polymerase Chain Reaction; Reproducibility of Results; Sensitivity and Specificity; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
PubMed: 29460728
DOI: 10.3201/eid2403.170459 -
Microbiology Spectrum Aug 2023Haemophilus seminalis is a newly proposed species that is phylogenetically related to Haemophilus haemolyticus. The distribution of in the human population, its genomic...
Haemophilus seminalis is a newly proposed species that is phylogenetically related to Haemophilus haemolyticus. The distribution of in the human population, its genomic diversity, and its pathogenic potential are still unclear. This study reports the finding of our comparative genomic analyses of four newly isolated Haemophilus strains (SZY H8, SZY H35, SZY H36, and SZY H68) from human sputum specimens (Guangzhou, China) along with the publicly available genomes of other phylogenetically related Haemophilus species. Based on pairwise comparisons of the 16S rRNA gene sequences, the four isolates showed <98.65% sequence identity to the type strains of all known Haemophilus species but were identified as belonging to , based on comparable phenotypic and genotypic features. Additionally, the four isolates showed high genome-genome relatedness indices (>95% ANI values) with 17 strains that were previously identified as either "" or hemin (X-factor)-independent H. haemolyticus and therefore required a more detailed classification study. Phylogenetically, these isolates, along with the two previously described isolates (a total of 23 isolates), shared a highly homologous lineage that is distinct from the clades of the main H. haemolyticus and Haemophilus influenzae strains. These isolates present an open pangenome with multiple virulence genes. Notably, all 23 isolates have a functional heme biosynthesis pathway that is similar to that of . The phenotype of hemin (X-factor) independence and the analysis of the , , and genes can be used to distinguish these isolates from H. haemolyticus and H. influenzae. Based on the above findings, we propose a reclassification for all ". " and two H. haemolyticus isolates belonging to with an emended description of This study provides a more accurate identification of Haemophilus isolates for use in the clinical laboratory and a better understanding of the clinical significance and genetic diversity in human environments. As a versatile opportunistic pathogen, the accurate identification of Haemophilus species is a challenge in clinical practice. In this study, we characterized the phenotypic and genotypic features of four strains that were isolated from human sputum specimens and propose the ". " and hemin (X-factor)-independent H. haemolyticus isolates as belonging to . The prediction of virulence-related genes indicates that isolates carry several virulence genes that are likely to play an important role in its pathogenicity. In addition, we depict that the genes , , and can be used as biomarkers for distinguishing from H. haemolyticus and H. influenzae. Our findings provide some insights into the identification, epidemiology, genetic diversity, pathogenic potential, and antimicrobial resistance of the newly proposed . .
Topics: Humans; RNA, Ribosomal, 16S; Hemin; Haemophilus; Haemophilus influenzae; Genomics; Phylogeny; Genetic Variation
PubMed: 37382545
DOI: 10.1128/spectrum.04772-22 -
Structure (London, England : 1993) Feb 2021Bacterial type II toxin-antitoxin (TA) modules encode a toxic protein that downregulates metabolism and a specific antitoxin that binds and inhibits the toxin during...
Bacterial type II toxin-antitoxin (TA) modules encode a toxic protein that downregulates metabolism and a specific antitoxin that binds and inhibits the toxin during normal growth. In non-typeable Haemophilus influenzae, a common cause of infections in humans, the vapXD locus was found to constitute a functional TA module and contribute to pathogenicity; however, the mode of action of VapD and the mechanism of inhibition by the VapX antitoxin remain unknown. Here, we report the structure of the intact H. influenzae VapXD complex, revealing an unusual 2:1 TA molecular stoichiometry where a Cas2-like homodimer of VapD binds a single VapX antitoxin. VapX consists of an oligonucleotide/oligosaccharide-binding domain that docks into an asymmetrical cavity on the toxin dimer. Structures of isolated VapD further reveal how a symmetrical toxin homodimer adapts to interacting with an asymmetrical antitoxin and suggest how a primordial TA system evolved to become part of CRISPR-Cas immunity systems.
Topics: Bacterial Proteins; Bacterial Toxins; Binding Sites; Haemophilus influenzae; Membrane Glycoproteins; Molecular Docking Simulation; Protein Domains; Toxin-Antitoxin Systems
PubMed: 33096014
DOI: 10.1016/j.str.2020.10.002 -
The Kaohsiung Journal of Medical... Apr 2018Aggregatibacter (Actinobacillus) actimycetemcomitans (Aa) is a gram-negative bacterium that colonizes the human oral cavity and is causative agent for localized... (Review)
Review
Aggregatibacter (Actinobacillus) actimycetemcomitans (Aa) is a gram-negative bacterium that colonizes the human oral cavity and is causative agent for localized aggressive (juvenile) periodontitis (AgP). In the middle of 1990s, a specific JP2 clone of belonging to the cluster of serotype b strains of Aa with highly leukotoxicity (leukotoxin, LtxA) able to kill human immune cells was isolated. JP2 clone of Aa was strongly associated with in particularly in rapidly progressing forms of aggressive periodontitis. The JP2 clone of Aa is transmitted through close contacts. Therefore, AgP patients need intense monitoring of their periodontal status as the risk for developing severely progressing periodontitis lesions are relatively high. Furthermore, timely periodontal treatment, including periodontal surgery supplemented by the use of antibiotics, is warranted. More importantly, periodontal attachment loss should be prevented by early detection of the JP2 clone of Aa by microbial diagnosis testing and/or preventive means.
Topics: Aggregatibacter actinomycetemcomitans; Aggressive Periodontitis; Caspase 1; Cell Death; Clone Cells; Exotoxins; Gene Expression Regulation; History, 20th Century; Host-Pathogen Interactions; Humans; Interleukin-18; Interleukin-1beta; Leukocytes, Mononuclear; Lymphocyte Function-Associated Antigen-1; Mouth; Pasteurellaceae Infections; Protein Binding; Signal Transduction
PubMed: 29655406
DOI: 10.1016/j.kjms.2018.01.014