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Journal of Clinical Microbiology Dec 2013The Verigene Gram-positive blood culture (BC-GP) assay (Nanosphere, Northbrook, IL) is a molecular method for the rapid identification of Gram-positive organisms and... (Comparative Study)
Comparative Study
The Verigene Gram-positive blood culture (BC-GP) assay (Nanosphere, Northbrook, IL) is a molecular method for the rapid identification of Gram-positive organisms and resistance markers directly from blood culture bottles. A total of 148 VersaTREK REDOX 1 40-ml aerobic bottles demonstrating Gram-positive bacteria were tested. Results were compared with those from conventional biochemical and matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) identifications. We obtained isolates of methicillin-resistant Staphylococcus aureus (MRSA) (24), methicillin-susceptible Staphylococcus aureus (MSSA) (14), methicillin-resistant Staphylococcus epidermidis (MRSE) (17), methicillin-susceptible Staphylococcus epidermidis (MSSE) (9), other coagulase-negative staphylococci (19), Streptococcus salivarius (5), Streptococcus parasanguinis (2), Streptococcus sanguinis (1), Streptococcus cristatus (1), the Streptococcus bovis group (5), Streptococcus agalactiae (9), the Streptococcus anginosus group (1), Streptococcus pneumoniae (6), vancomycin-resistant Enterococcus faecium (VRE FCM) (16), vancomycin-susceptible Enterococcus faecalis (3), Aerococcus viridans (2), Bacillus (6), Corynebacterium (8), Lactobacillus (2), Micrococcus (2), Neisseria mucosa (1), Escherichia coli (3), Candida tropicalis (1), Propionibacterium (1), and Rothia (1). Overall agreement with the culture results was 95%. A total of 137 of 138 (99%) monomicrobial cultures were concordant. We tested 9 polymicrobial samples and found 33% agreement. A chart review of 31 patients with MRSA, MSSA, or VRE demonstrated that the Nanosphere BC-GP assay might have led to more appropriate antibiotic selection for these patients an average of 42 h earlier. Additionally, contact isolation could have been initiated an average of 37 h earlier for patients with MRSA or VRE. The BC-GP assay may have a positive impact on patient care, health care costs, and antibiotic stewardship.
Topics: Anti-Bacterial Agents; Bacteremia; Bacteriological Techniques; Blood; Drug Resistance, Bacterial; Gram-Positive Bacteria; Gram-Positive Bacterial Infections; Humans; Molecular Diagnostic Techniques; Specimen Handling
PubMed: 24048531
DOI: 10.1128/JCM.01889-13 -
Caries Research 2010Severe early childhood caries is a microbial infection that severely compromises the dentition of young children. The aim of this study was to characterize the... (Comparative Study)
Comparative Study
BACKGROUND/AIMS
Severe early childhood caries is a microbial infection that severely compromises the dentition of young children. The aim of this study was to characterize the microbiota of severe early childhood caries.
METHODS
Dental plaque samples from 2- to 6-year-old children were analyzed using 16S rRNA gene cloning and sequencing, and by specific PCR amplification for Streptococcus mutans and Bifidobacteriaceae species.
RESULTS
Children with severe caries (n = 39) had more dental plaque and gingival inflammation than caries-free children (n = 41). Analysis of phylotypes from operational taxonomic unit analysis of 16S rRNA clonal metalibraries from severe caries and caries-free children indicated that while libraries differed significantly (p < 0.0001), there was increased diversity than detected in this clonal analysis. Using the Human Oral Microbiome Database, 139 different taxa were identified. Within the limits of this study, caries-associated taxa included Granulicatella elegans (p < 0.01) and Veillonella sp. HOT-780 (p < 0.01). The species associated with caries-free children included Capnocytophaga gingivalis (p < 0.01), Abiotrophia defectiva (p < 0.01), Lachnospiraceae sp. HOT-100 (p < 0.05), Streptococcus sanguinis (p < 0.05) and Streptococcus cristatus (p < 0.05). By specific PCR, S. mutans (p < 0.005) and Bifidobacteriaceae spp. (p < 0.0001) were significantly associated with severe caries.
CONCLUSION
Clonal analysis of 80 children identified a diverse microbiota that differed between severe caries and caries-free children, but the association of S. mutans with caries was from specific PCR analysis, not from clonal analysis, of samples.
Topics: Abiotrophia; Actinobacteria; Bacteria; Bifidobacterium; Capnocytophaga; Carnobacteriaceae; Child; Child, Preschool; Clone Cells; Cloning, Molecular; Dental Caries; Dental Enamel; Dental Plaque; Dental Plaque Index; Dental Pulp Exposure; Dentin; Female; Gingivitis; Gram-Positive Bacteria; Humans; Male; Metagenome; Periodontal Index; RNA, Ribosomal, 16S; Streptococcus; Streptococcus mutans; Veillonella
PubMed: 20861633
DOI: 10.1159/000320158 -
Journal of Bacteriology Jun 2008Streptococcus cristatus ArcA inhibits production of a major adhesin, FimA, in Porphyromonas gingivalis, a primary periodontal pathogen. In this study, we demonstrate the...
Streptococcus cristatus ArcA inhibits production of a major adhesin, FimA, in Porphyromonas gingivalis, a primary periodontal pathogen. In this study, we demonstrate the differential expression of arcA in two streptococcal species. The expression level of arcA in streptococci appears to be controlled by both cis and trans elements.
Topics: Bacterial Proteins; Base Sequence; Blotting, Western; Fimbriae Proteins; Gene Expression Regulation, Bacterial; Hydrolases; Molecular Sequence Data; Porphyromonas gingivalis; Streptococcus
PubMed: 18408031
DOI: 10.1128/JB.01898-07 -
The Journal of Antimicrobial... Nov 2007The aim of this study was to investigate the transfer of bacterial doxycycline resistance between oral bacteria in subjects receiving systemic doxycycline for the...
OBJECTIVES
The aim of this study was to investigate the transfer of bacterial doxycycline resistance between oral bacteria in subjects receiving systemic doxycycline for the treatment of periodontitis.
PATIENTS AND METHODS
Streptococci were cultured before and after treatment from the subgingival plaque of two patients with periodontitis, genotyped and investigated for the presence of antimicrobial resistance determinants and conjugative transposons.
RESULTS
In one subject, a strain of Streptococcus sanguinis resistant to doxycycline was a minor component of the pre-treatment streptococcal flora but dominated post-treatment. In a second subject, a strain of Streptococcus cristatus, which was sensitive to doxycycline before treatment, was found to have acquired a novel conjugative transposon during treatment, rendering it resistant to doxycycline and erythromycin. The novel transposon, named CTn6002, was sequenced and found to be a complex element derived in part from Tn916, and an unknown element which included the erythromycin resistance gene erm(B). A strain of Streptococcus oralis isolated from this subject pre-treatment was found to harbour CTn6002 and was therefore implicated as the donor.
CONCLUSIONS
This is the first direct demonstration of transfer of antimicrobial resistance carried on a conjugative transposon between oral bacteria during systemic antimicrobial treatment of periodontitis in humans.
Topics: Anti-Bacterial Agents; Bacterial Proteins; Conjugation, Genetic; DNA Transposable Elements; DNA, Bacterial; Doxycycline; Drug Resistance, Bacterial; Erythromycin; Gene Expression Regulation, Bacterial; Humans; Periodontal Diseases; Phylogeny; Streptococcal Infections; Streptococcus
PubMed: 17855723
DOI: 10.1093/jac/dkm331 -
Clinical Nuclear Medicine Nov 2018A 47-year-old man, with a history of anabolic steroid abuse, developed hepatic adenomatosis and multifocal hepatocellular carcinoma. He underwent ultrasound and CT...
A 47-year-old man, with a history of anabolic steroid abuse, developed hepatic adenomatosis and multifocal hepatocellular carcinoma. He underwent ultrasound and CT follow-up, showing multiple solid and fluid hepatic lesions. Consequently, hospitalization was required because of high fever (up to 39°C), weakness, and anorexia. An abdominal CT scan revealed an enlargement of one of the intrahepatic fluid collections. Biochemical and microbiological analyses of a fluid sample showed bilirubin and bile acids as well as Streptococcus cristatus and Enterobacter cloacae. Thus, the patient underwent Tc-trimethylbromo-iminodiacetic acid scintigraphy, demonstrating bile collection in the lesion with a flow from a bile duct.
Topics: Bile; Carcinoma, Hepatocellular; Humans; Liver Neoplasms; Male; Middle Aged; Radionuclide Imaging; Tomography, X-Ray Computed; Ultrasonography
PubMed: 30222677
DOI: 10.1097/RLU.0000000000002272 -
Frontiers in Pediatrics 2020Molecular assays for infectious diseases have emerged as important clinical decision-making tools. Unbiased, metagenomic next-generation sequencing is a novel approach...
Molecular assays for infectious diseases have emerged as important clinical decision-making tools. Unbiased, metagenomic next-generation sequencing is a novel approach holding promise to detect pathogens missed by conventional modalities and to deconvolute admixed nucleic acid sequences from polymicrobial infections in order to identify constituent pathogens. Recent studies have raised concerns about the clinical impact of metagenomics assays and whether their expense is justified. Here, we report a case of polyclonal endocarditis in a 14-year-old woman with a history of Tetralogy of Fallot. Three sets of admission blood cultures and a commercial plasma metagenomics assay were negative for pathogens, despite persistent vegetations observed on the valve during a later procedure. Multiple strains of were identified from the explanted valve by amplicon-based 16S rRNA sequencing, confirming the patient had received appropriate antibiotic therapy. This case highlights limitations in the use and interpretation of clinical metagenomics for infectious disease diagnosis and indicates that the clinical yield of these tools may depend upon infection type and anatomic location.
PubMed: 33489996
DOI: 10.3389/fped.2020.575674 -
The Journal of Antimicrobial... Mar 2011Ciprofloxacin is the most frequently used member of the fluoroquinolones during initial eradication therapy of Pseudomonas aeruginosa, as well as during acute pulmonary...
Molecular characterization and phylogenetic analysis of quinolone resistance-determining regions (QRDRs) of gyrA, gyrB, parC and parE gene loci in viridans group streptococci isolated from adult patients with cystic fibrosis.
OBJECTIVES
Ciprofloxacin is the most frequently used member of the fluoroquinolones during initial eradication therapy of Pseudomonas aeruginosa, as well as during acute pulmonary exacerbations. However, its long-term effect on the susceptibility of the commensal flora within the cystic fibrosis (CF) airways has not yet been examined. The aim of this study was therefore to examine the consequence of oral ciprofloxacin usage on the resistance of the commensal viridans group streptococci (VGS), in terms of MICs and mutational analysis of the quinolone resistance-determining regions (QRDRs).
METHODS
The MICs of ciprofloxacin, efflux activities and amino acid substitutions in the QRDRs for 190 isolates of VGS, originating from the sputa of adult CF patients who had been exposed constantly to ciprofloxacin, were examined. VGS organisms included Streptococcus salivarius, Streptococcus mitis, Streptococcus sanguinis, Streptococcus oralis, Streptococcus parasanguinis, Streptococcus infantis, Streptococcus gordonii, Streptococcus anginosus, Streptococcus cristatus, Streptococcus australis and Streptococcus mutans. Ciprofloxacin susceptibility was determined by broth microdilution and QRDRs within the gyrA, gyrB, parC and parE gene loci were explored using sequence analysis.
RESULTS
Twenty-seven (14.2%) streptococcal isolates were resistant to ciprofloxacin (MICs ≥8 mg/L) and 21 (11.1%) had reduced susceptibility (MICs 4 mg/L). As a comparator, clinically non-significant and non-invasive VGS organisms were examined in 12 consecutive non-CF patients in the community, where no resistance to ciprofloxacin was observed. Five novel QRDR PCR assays were developed to elucidate mutations within the CF VGS population, where there were six positions, which corresponded to previously reported quinolone resistance responsible mutations, and eight novel potential QRDR resistance mutations. Double mutations in gyrA and parC/parE led to MICs of 16 to >64 mg/L, while single mutations in parC or parE resulted in MICs of 8-32 mg/L and 8 mg/L, respectively. The mean homologies of each species to Streptococcus pneumoniae R6 were: gyrA, 70.3%-95%; gyrB, 69.6%-96.2%; parC, 76.1%-94.8%; and parE, 70.7%-94.7%. The close relatives of S. pneumoniae, S. mitis and S. oralis, showed high similarity for all four genes (more than 86%).
CONCLUSIONS
Treatment of P. aeruginosa with oral ciprofloxacin in patients with CF may concurrently reduce antibiotic susceptibility in the commensal VGS flora, where these organisms may potentially act as a reservoir of fluoroquinolone resistance gene determinants for newly acquired and antibiotic-susceptible pathogens, particularly the Streptococcus milleri group.
Topics: Adult; Anti-Bacterial Agents; Ciprofloxacin; Cystic Fibrosis; DNA Gyrase; DNA Topoisomerase IV; DNA, Bacterial; Drug Resistance, Bacterial; Drug Utilization; Female; Humans; Male; Microbial Sensitivity Tests; Middle Aged; Quinolones; Sequence Analysis, DNA; Streptococcal Infections; Viridans Streptococci
PubMed: 21193474
DOI: 10.1093/jac/dkq485 -
Microbiology Spectrum Oct 2021When encountering oxidative stress, organisms selectively upregulate antioxidant genes and simultaneously suppress the translation of most other proteins. Eukaryotes...
When encountering oxidative stress, organisms selectively upregulate antioxidant genes and simultaneously suppress the translation of most other proteins. Eukaryotes employ multiple strategies to adjust translation at both the initiation and elongation stages; however, how prokaryotes modulate translation under oxidative stress remains unclear. Here, we report that upon hydrogen peroxide (HO) challenge, Streptococcus oligofermentans reduced translation via RNase Z (So-RNaseZ) oxidative degradation, thus hindering tRNA maturation. S. oligofermentans encodes all CCA-less tRNAs that require So-RNaseZ for 3' end maturation. A combination of nonreducing SDS-PAGE and liquid chromatography/tandem mass spectrometry (LC/MS-MS) assays demonstrated that HO oxidation induced Cys38-Cys149 disulfide linkages in recombinant So-RNaseZ protein, and serine substitution of Cys38 or Cys149 abolished these disulfide linkages. Consistently, redox Western blotting also determined intramolecular disulfide-linked So-RNaseZ in HO-treated cells. The disulfide-linked So-RNaseZ and monomer were both subject to proteolysis, whereas C149S mutation alleviated oxidative degradation of So-RNaseZ, suggesting that HO-mediated disulfide linkages substantially contributed to So-RNaseZ degradation. Accordingly, Northern blotting determined that tRNA precursor accumulation and mature tRNA species decrease in HO-treated . Moreover, reduced overall protein synthesis, as indicated by puromycin incorporation, and retarded growth of occurred in an HO concentration-dependent manner. Overexpression of So-RNaseZ not only elevated tRNA precursor processing and protein synthesis but also partly rescued HO-suppressed growth. Moreover, So-RNaseZ oxidative degradation-mediated translation repression elevated survival under high HO stress. Therefore, this work found that So-RNaseZ oxidative degradation-impeded tRNA maturation contributes to streptococcal translation repression and provides the oxidative stress adaptability for . Translation regulation is a common strategy used by organisms to reduce oxidative damage. Catalase-negative streptococci produce as well as tolerate high levels of HO. This work reports a novel translation regulation mechanism employed by Streptococcus oligofermentans in response to HO challenge, in which the key tRNA endonuclease So-RNaseZ is oxidized to form Cys38-Cys149 disulfide linkages and both the disulfide-linked So-RNaseZ and monomers are subject to proteolysis; thus, tRNA maturation, protein translation, and growth are all suppressed. Notably, So-RNaseZ oxidative degradation-mediated translation repression offers oxidative adaptability to and enhances its survival against high HO challenge. So-RNaseZ orthologs and HO-sensitive cysteines (Cys38 and Cys149) are widely distributed in and species genomes, which also encode all CCA-less tRNAs and lack catalase. Therefore, RNase Z oxidative degradation-based translation regulation could be widely employed by these lactic acid bacteria, including pathogenic streptococci, to cope with HO.
Topics: Antioxidants; Disulfides; Endoribonucleases; Gene Expression Regulation, Bacterial; Hydrogen Peroxide; Oxidative Stress; Protein Biosynthesis; RNA, Transfer; Streptococcus
PubMed: 34704809
DOI: 10.1128/Spectrum.01167-21 -
Oral Microbiology and Immunology Dec 2008Microbial interactions are considered important in the adhesion process of pathogenic bacteria in the oral cavity. This study addressed the hypothesis that a...
INTRODUCTION
Microbial interactions are considered important in the adhesion process of pathogenic bacteria in the oral cavity. This study addressed the hypothesis that a streptococcal biofilm influences the hard tissue colonization by the periodontopathogen Aggregatibacter actinomycetemcomitans under hydrodynamic conditions.
METHODS
The colonization of a green-fluorescent-protein-labelled A. actinomycetemcomitans strain on surfaces coated with a streptococcal biofilm, was monitored in real time using a confocal laser scanning microscope-mounted flow cell. Culture and quantitative polymerase chain reaction data were obtained in parallel from a Modified Robbins Device.
RESULTS
Colonization of A. actinomycetemcomitans was inhibited by the four tested streptococci (Streptococcus sanguinis, Streptococcus cristatus, Streptococcus salivarius, and Streptococcus mitis). The most inhibiting species was S. sanguinis.
CONCLUSION
These results confirmed the hypothesis that some bacterial species influence A. actinomycetemcomitans colonization of hard surfaces in vitro under hydrodynamic conditions.
Topics: Aggregatibacter actinomycetemcomitans; Antibiosis; Bacterial Adhesion; Biofilms; Streptococcus
PubMed: 18954361
DOI: 10.1111/j.1399-302X.2008.00456.x -
Molecular Oral Microbiology Aug 2015Dental biofilm development is a sequential process, and adherence between microbes and the salivary pellicle (adhesion) as well as among different microbes (co-adhesion...
A YadA-like autotransporter, Hag1 in Veillonella atypica is a multivalent hemagglutinin involved in adherence to oral streptococci, Porphyromonas gingivalis, and human oral buccal cells.
Dental biofilm development is a sequential process, and adherence between microbes and the salivary pellicle (adhesion) as well as among different microbes (co-adhesion or coaggregation) plays a critical role in building a biofilm community. The Veillonella species are among the most predominant species in the oral cavity and coaggregate with many initial, early, middle, and late colonizers. Similar to oral fusobacteria, they are also considered bridging species in biofilm development. However, the mechanism of this ability has yet to be reported, due to the previous lack of a genetic transformation system in the entire genus. In this study, we used our recently discovered transformable Veillonella strain, Veillonella atypica OK5, to probe the mechanism of coaggregation between Veillonella species and other oral bacteria. By insertional inactivation of all eight putative hemagglutinin genes, we identified one gene, hag1, which is involved in V. atypica coaggregation with the initial colonizers Streptococcus gordonii, Streptococcus oralis and Streptococcus cristatus, and the periodontal pathogen Porphyromonas gingivalis. The hag1 mutant also abolished adherence to human buccal cells. Inhibition assays using various chemical or physiological treatments suggest different mechanisms being involved in coaggregation with different partners. The entire hag1 gene was sequenced and shown to be the largest known bacterial hemagglutinin gene.
Topics: Bacterial Adhesion; Bacterial Proteins; Biofilms; Genes, Bacterial; Hemagglutinins; Humans; Microbial Interactions; Molecular Sequence Data; Mouth; Mouth Mucosa; Mutation; Porphyromonas gingivalis; Sequence Analysis, DNA; Streptococcus; Streptococcus gordonii; Streptococcus oralis; Type V Secretion Systems; Veillonella
PubMed: 25440509
DOI: 10.1111/omi.12091