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Microbiology Spectrum Dec 2017There is currently only limited information on the antimicrobial susceptibility and resistance of spp., spp., and from animals. The comparability of the data is...
There is currently only limited information on the antimicrobial susceptibility and resistance of spp., spp., and from animals. The comparability of the data is hampered by the use of different antimicrobial susceptibility testing methods and interpretive criteria. To date, standard broth microdilution methods and clinical breakpoints that are approved by the Clinical and Laboratory Standards Institute and are applicable to spp., spp., and are available. The lack of species-specific clinical breakpoints for the different animal species reduces the explanatory power of the data. Among the isolates of the three genera, elevated MICs for different classes of antimicrobial agents (e.g., β-lactams, macrolides, lincosamides, tetracyclines, aminoglycosides, phenicols, sulfonamides/diaminopyrimidines, and fluoroquinolones) have been described. The most comprehensive data set is available for , which also includes information about genes and mutations involved in antimicrobial resistance. In isolates, the macrolide-lincosamide-streptogramin B resistance genes (B) and (X) were identified. Tetracycline resistance in was based on the resistance genes (W), (Z), and (33), whereas the aminoglycoside resistance genes , , , , , and have been described in . So far, only single genes conferring either phenicol resistance (), trimethoprim resistance (), or β-lactam resistance () are known to occur in isolates. Various 23S rRNA mutations, including A2058T, A2058G, and G2137C, were identified in macrolide/lincosamide-resistant .
Topics: Actinomycetaceae; Animal Diseases; Animals; Anti-Bacterial Agents; Arcanobacterium; Corynebacterium; Drug Resistance, Bacterial; Genes, MDR; Microbial Sensitivity Tests; Mutation; RNA, Ribosomal, 23S; Species Specificity
PubMed: 29219109
DOI: 10.1128/microbiolspec.ARBA-0021-2017 -
Veterinary Research Jan 2022Trueperella pyogenes (T. pyogenes) is an opportunistic pathogen associated with a variety of diseases in many domestic animals. Therapeutic treatment options for T....
Trueperella pyogenes (T. pyogenes) is an opportunistic pathogen associated with a variety of diseases in many domestic animals. Therapeutic treatment options for T. pyogenes infections are becoming limited due to antimicrobial resistance, in which efflux pumps play an important role. This study aims to evaluate the inhibitory activity of luteolin, a natural flavonoid, on the MsrA efflux pump and investigate its mechanism. The results of antimicrobial susceptibility testing indicated that the susceptibility of msrA-positive T. pyogenes isolates to six macrolides increased after luteolin treatment, while the susceptibility of msrA-negative isolates showed no change after luteolin treatment. It is suspected that luteolin may increase the susceptibility of T. pyogenes isolates by inhibiting MsrA activity. After 1/2 MIC luteolin treatment for 36 h, the transcription level of the msrA gene and the expression level of the MsrA protein decreased by 55.0-97.7% and 36.5-71.5%, respectively. The results of an affinity test showed that the equilibrium dissociation constant (KD) of luteolin and MsrA was 6.462 × 10 M, and hydrogen bonding was predominant in the interaction of luteolin and MsrA. Luteolin may inhibit the ATPase activity of the MsrA protein, resulting in its lack of an energy source. The current study illustrates the effect of luteolin on MsrA in T. pyogenes isolates and provides insight into the development of luteolin as an innovative agent in combating infections caused by antimicrobial-resistant bacteria.
Topics: Actinomycetaceae; Animals; Animals, Domestic; Anti-Bacterial Agents; Drug Resistance, Bacterial; Luteolin; Macrolides; Microbial Sensitivity Tests
PubMed: 35012652
DOI: 10.1186/s13567-021-01021-w -
Nucleic Acids Research Jun 2021k-Turns are widespread key architectural elements that occur in many classes of RNA molecules. We have shown previously that their folding properties (whether or not...
k-Turns are widespread key architectural elements that occur in many classes of RNA molecules. We have shown previously that their folding properties (whether or not they fold into their tightly kinked structure on addition of metal ions) and conformation depend on their local sequence, and we have elucidated a series of rules for prediction of these properties from sequence. In this work, we have expanded the rules for prediction of folding properties, and then applied the full set to predict the folding and conformation of four probable k-turns we have identified amongst 224 structured RNA species found in bacterial intergenenic regions by the Breaker lab (1). We have analyzed the ion-dependence of folding of the four k-turns using fluorescence resonance energy transfer, and determined the conformation of two of them using X-ray crystallography. We find that the experimental data fully conform to both the predicted folding and conformational properties. We conclude that our folding rules are robust, and can be applied to new k-turns of unknown characteristics with confidence.
Topics: Actinomyces; Crystallography, X-Ray; Fluorescence Resonance Energy Transfer; Haloarcula marismortui; Ions; Magnesium; Metals; Models, Molecular; Nucleic Acid Conformation; RNA; RNA Folding; RNA, Double-Stranded
PubMed: 33978763
DOI: 10.1093/nar/gkab333 -
Microbiology Spectrum Dec 2021The growing application of metagenomics to different ecological and microbiome niches in recent years has enhanced our knowledge of global microbial biodiversity. Among...
The growing application of metagenomics to different ecological and microbiome niches in recent years has enhanced our knowledge of global microbial biodiversity. Among these abundant and widespread microbes, the candidate phyla radiation (CPR) group has been recognized as representing a large proportion of the microbial kingdom (>26%). CPR are characterized by their obligate symbiotic or exoparasitic activity with other microbial hosts, mainly bacteria. Currently, isolating CPR is still considered challenging for microbiologists. The idea of this study was to develop an adapted protocol for the coculture of CPR with a suitable bacterial host. Based on various sputum samples, we tried to enrich CPR ( members) and to cocultivate them with pure hosts (Schaalia odontolytica). This protocol was monitored by TaqMan real-time quantitative PCR (qPCR) using a system specific for designed in this study, as well as by electron microscopy and sequencing. We succeeded in coculturing and sequencing the complete genomes of two new species, " Minimicrobia naudis" and " Minimicrobia vallesae." In addition, we noticed a decrease in the values of and a significant multiplication through their physical association with Schaalia odontolytica strains in the enriched medium that we developed. This work may help bridge gaps in the genomic database by providing new CPR members, and in the future, their currently unknown characteristics may be revealed. In this study, the first TaqMan real-time quantitative PCR (qPCR) system, targeting phylum, has been developed. This technique can specifically quantify members in any sample of interest in order to investigate their prevalence. In addition, another easy, specific, and sensitive protocol has been developed to maintain the viability of cells in an enriched medium with their bacterial host. The use of this protocol facilitates subsequent studies of the phenotypic characteristics of CPR and their physical interactions with bacterial species, as well as the sequencing of new genomes to improve the current database.
Topics: Actinomycetaceae; Bacteria; Coculture Techniques; Culture Media; Humans; Microbiota; Polymerase Chain Reaction
PubMed: 35007432
DOI: 10.1128/spectrum.01069-21 -
Journal of Virology Sep 2022Bacteriophages (phages) are an integral part of the human oral microbiome. Their roles in modulating bacterial physiology and shaping microbial communities have been...
Bacteriophages (phages) are an integral part of the human oral microbiome. Their roles in modulating bacterial physiology and shaping microbial communities have been discussed but remain understudied due to limited isolation and characterization of oral phage. Here, we report the isolation of LC001, a lytic phage targeting human oral Schaalia odontolytica (formerly known as Actinomyces odontolyticus) strain XH001. We showed that LC001 attached to and infected surface-grown, but not planktonic, XH001 cells, and it displayed remarkable host specificity at the strain level. Whole-genome sequencing of spontaneous LC001-resistant, surface-grown XH001 mutants revealed that the majority of the mutants carry nonsense or frameshift mutations in XH001 gene (renamed ), which encodes a putative lytic transglycosylase (LT). The mutants are defective in LC001 binding, as revealed by direct visualization of the significantly reduced attachment of phage particles to the XH001 spontaneous mutants compared that to the wild type. Meanwhile, targeted deletion of produced a mutant that is defective in LC001 binding and resistant to LC001 infection even as surface-grown cells, while complementation of in the mutant background restored the LC001-sensitive phenotype. Intriguingly, similar expression levels of were observed in surface-grown and planktonic XH001, which displayed LC001-binding and nonbinding phenotypes, respectively. Furthermore, the overexpression of failed to confer an LC001-binding and -sensitive phenotype to planktonic XH001. Thus, our data suggested that rather than directly serving as a phage receptor, -encoded LT may increase the accessibility of phage receptor, possibly via its enzymatic activity, by cleaving the peptidoglycan structure for better receptor exposure during peptidoglycan remodeling, a function that can be exploited by LC001 to facilitate infection. The evidence for the presence of a diverse and abundant phage population in the host-associated oral microbiome came largely from metagenomic analysis or the observation of virus-like particles within saliva/plaque samples, while the isolation of oral phage and investigation of their interaction with bacterial hosts are limited. Here, we report the isolation of LC001, the first lytic phage targeting oral Schaalia odontolytica. Our study suggested that LC001 may exploit the host bacterium-encoded lytic transglycosylase function to gain access to the receptor, thus facilitating its infection.
Topics: Actinomycetaceae; Bacteriophage Receptors; Bacteriophages; Glycosyltransferases; Host Specificity; Humans; Microbiota; Mouth; Mutation; Peptidoglycan; Plankton; Viral Proteins
PubMed: 36000841
DOI: 10.1128/jvi.01063-22 -
Journal of Clinical Microbiology Jan 2015Outbreaks and pseudo-outbreaks of infection related to bronchoscopy typically involve Gram-negative bacteria, Mycobacterium species or Legionella species. We report an...
Outbreaks and pseudo-outbreaks of infection related to bronchoscopy typically involve Gram-negative bacteria, Mycobacterium species or Legionella species. We report an unusual bronchoscopy-related pseudo-outbreak due to Actinomyces graevenitzii. Extensive epidemiological and microbiological investigation failed to identify a common source. Strain typing revealed that the cluster was comprised of heterogeneous strains of A. graevenitzii. A change in laboratory procedures for Actinomyces cultures was coincident with the emergence of the pseudo-outbreak, and we determined that A. graevenitzii isolates more readily adopted a white, dry, molar tooth appearance on anaerobic colistin nalidixic acid (CNA) agar which likely facilitated its detection and identification in bronchoscopic specimens. This unusual pseudo-outbreak was related to frequent requests of bronchoscopists for Actinomyces cultures combined with a change in microbiology laboratory practices.
Topics: Actinomyces; Actinomycosis; Bacterial Load; Bronchoscopy; Case-Control Studies; Cross Infection; Disease Outbreaks; Equipment Contamination; Humans; Polymerase Chain Reaction; Tertiary Care Centers
PubMed: 25355767
DOI: 10.1128/JCM.02302-14 -
BMC Infectious Diseases May 2020Brain abscesses are the rare and most severe form of actinomycosis, which usually manifests as abscesses of the occipital or parietal lobe due to direct expansion from...
BACKGROUND
Brain abscesses are the rare and most severe form of actinomycosis, which usually manifests as abscesses of the occipital or parietal lobe due to direct expansion from an adjacent area, the oral cavity. In the medical literature, there are only a few reported cases of brain abscess caused by Actinomyces meyeri. In this report, we present a 35-year-old male patient who experienced an insidious headache and left-sided weakness and was diagnosed with an Actinomyces meyeri brain abscess.
CASE PRESENTATION
A 35-year-old Nepalese man came to our institute with the primary complaint of insidious onset of headache and left-sided weakness. His physical examination was remarkable for the left-sided weakness with power 2/5 on both upper and lower limbs, hypertonia, hyperreflexia and positive Babinski sign, with intact sensory function. Cardiac examination revealed systolic murmur with regular S1 and S2, and lung examination was normal. The patient had poor dental hygiene. Biochemistry and haematology panel were normal. Urinalysis, chest X-ray and electrocardiogram revealed no abnormality. A transthoracic echocardiogram revealed mitral regurgitation. However, there was no evidence of valvular vegetation. A magnetic resonance imaging (MRI) of the brain was performed, which showed a bi-lobed rim enhancing lesion with a conglomeration of two adjoining round lesions in the right parietal parasagittal region. Perilesional oedema resulting in mass effect over the right lateral ventricle and mid-right uncal herniation with midline shift was noted. Craniotomy was performed, and the lesion was excised. Gram staining of the extracted sample revealed gram variable filamentous rods. Creamy white, moist, confluent colonies were observed after performing anaerobic culture in chocolate agar. On the gram staining, they showed gram-positive filamentous rods. Actinomyces meyeri was identified based on matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) technology. Based on the susceptibilities, he was successfully treated with ampicillin-sulbactam.
CONCLUSIONS
In conclusion, Actinomyces should be considered in the differential diagnosis of brain abscess in patients with poor dental hygiene, and early diagnosis and appropriate treatment can lead to better results.
Topics: Actinomyces; Actinomycosis; Adult; Brain Abscess; Headache; Humans; Magnetic Resonance Imaging; Male; Radiography
PubMed: 32460724
DOI: 10.1186/s12879-020-05100-9 -
The ISME Journal Dec 2020Host range is a fundamental component of symbiotic interactions, yet it remains poorly characterized for the prevalent yet enigmatic subcategory of bacteria/bacteria...
Host range is a fundamental component of symbiotic interactions, yet it remains poorly characterized for the prevalent yet enigmatic subcategory of bacteria/bacteria symbioses. The recently characterized obligate bacterial epibiont Candidatus Nanosynbacter lyticus TM7x with its bacterial host Actinomyces odontolyticus XH001 offers an ideal system to study such a novel relationship. In this study, the host range of TM7x was investigated by coculturing TM7x with various related Actinomyces strains and characterizing their growth dynamics from initial infection through subsequent co-passages. Of the twenty-seven tested Actinomyces, thirteen strains, including XH001, could host TM7x, and further classified into "permissive" and "nonpermissive" based on their varying initial responses to TM7x. Ten permissive strains exhibited growth/crash/recovery phases following TM7x infection, with crash timing and extent dependent on initial TM7x dosage. Meanwhile, three nonpermissive strains hosted TM7x without a growth-crash phase despite high TM7x dosage. The physical association of TM7x with all hosts, including nonpermissive strains, was confirmed by microscopy. Comparative genomic analyses revealed distinguishing genomic features between permissive and nonpermissive hosts. Our results expand the concept of host range beyond a binary to a wider spectrum, and the varying susceptibility of Actinomyces strains to TM7x underscores how small genetic differences between hosts can underly divergent selective trajectories.
Topics: Actinomyces; Bacteria; Host Specificity; Symbiosis
PubMed: 32839546
DOI: 10.1038/s41396-020-00736-6 -
Clinical and Experimental Rheumatology 2021To identify novel autoantigens from circulating immune complexes (CICs) in rheumatoid arthritis (RA) patients and further explore their clinical significance.
OBJECTIVES
To identify novel autoantigens from circulating immune complexes (CICs) in rheumatoid arthritis (RA) patients and further explore their clinical significance.
METHODS
From serum samples of 10 early RA (ERA) patients and 10 healthy donors, CICs were isolated and subjected to orbitrap mass spectrometry for autoantigen identification. Antibodies against the peptidoglycan recognition protein-2 (PGLYRP-2) derived from CICs were further detected by indirect enzyme-linked immunosorbent assay (ELISA) in 178 patients with RA, compared with 59 osteoarthritis (OA), 59 systemic lupus erythematosus (SLE), 55 ankylosing spondylitis (AS), 95 primary Sjögren's syndrome (pSS) and 50 healthy controls (HC).
RESULTS
Thirty-three potential antigens out of 323 proteins were identified from CICs of RA patients. The autoantibodies to PGLYRP-2 were significantly increased in RA patients with 42.70% sensitivity and 85.20% specificity in comparison to other rheumatic diseases and healthy controls. The prevalence of anti-PGLYRP-2 was also elevated in subgroups of RA, with 34.72% in ERA, 35.29% in RF negative and 42.86% in anti-CCP negative patients. Further analysis suggested that anti-PGLYRP-2 was potentially accompanied with production of other autoantibodies in RA. In addition, we found by homology analysis that an epitope of PGLYRP-2442-447 mimics amino acid residues 431-436 of N-acetylmuramoyl-L-alanine amidase (NAMLAA) in actinomyces naeslundii.
CONCLUSIONS
Autoantibody against PGLYRP-2 was identified as a promising biomarker in RA, especially in early and seronegative patients.
Topics: Actinomyces; Arthritis, Rheumatoid; Autoantibodies; Biomarkers; Carrier Proteins; Enzyme-Linked Immunosorbent Assay; Humans; Lupus Erythematosus, Systemic
PubMed: 33427621
DOI: 10.55563/clinexprheumatol/vlvlqu -
Scientific Reports Aug 2016Medication-related osteonecrosis of the jaw (MRONJ) represents a complication of bisphosphonate treatment that responds poorly to standard treatment. In a retrospective...
Medication-related osteonecrosis of the jaw (MRONJ) represents a complication of bisphosphonate treatment that responds poorly to standard treatment. In a retrospective cohort study we investigated a possible role of Actinomyces spp. in the pathogenesis of MRONJ. Deep biopsies of necrotic bone were collected during surgical treatment of MRONJ and evaluated by histology and microbiology for the presence of Actinomyces spp. Microbiological, demographic and clinicpathological data were analyzed for risk of Actinomyces-associated MRONJ. Between 2005 and 2014, 111 patients suffering from histologically-confirmed MRONJ were identified. Actinomyces spp. were detected in 99 cases (89%) by histology and in six further patients by microbiological culture. A diverse microbial flora was found in all specimens without association with Actinomyces spp. Demographic and clinicopathological characteristics did not separate significantly Actinomyces-positive from Actinomyces-negative cases. Our observations confirm previous reports of a high prevalence of Actinomyces spp. in MRONJ in the single largest cohort available up to now. The high prevalence of Actinomyces spp. and the lack of clinicopathological risk factors underline the prominent role of Actinomyces spp. in MRONJ and may change the current understanding of MRONJ. Established prolonged antimicrobial treatment regimens against Actinomyces spp. infection could therefore be a mainstay of future MRONJ management.
Topics: Actinomyces; Aged; Diphosphonates; Female; Humans; Jaw Diseases; Male; Middle Aged; Osteonecrosis; Retrospective Studies; Risk Factors
PubMed: 27530150
DOI: 10.1038/srep31604