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Antimicrobial Agents and Chemotherapy Dec 2015Nutritionally variant streptococci (NVS) are fastidious Gram-positive cocci comprised of the species Abiotrophia defectiva, Granulicatella adiacens, and Granulicatella...
Nutritionally variant streptococci (NVS) are fastidious Gram-positive cocci comprised of the species Abiotrophia defectiva, Granulicatella adiacens, and Granulicatella elegans. NVS are an important cause of bacteremia and infective endocarditis (IE) associated with significant morbidity and mortality. Antimicrobial susceptibility testing (AST) was performed for 14 antimicrobials using the broth microdilution MIC method described in the Clinical and Laboratory Standards Institute (CLSI) M45 guideline. A total of 132 clinical NVS blood isolates collected from 2008 to 2014 were tested. Species level identification of NVS isolates was achieved by 16S rRNA gene sequencing and/or matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). Ninety isolates were identified as G. adiacens, 37 as A. defectiva, and 5 as G. elegans. All isolates were susceptible to vancomycin (MIC90 = 1 μg/ml), and none displayed high-level resistance to aminoglycosides. G. adiacens was considerably more susceptible to penicillin than A. defectiva (38.9% versus 10.8% of isolates susceptible) but was less susceptible to cephalosporins than was A. defectiva (43.3% versus 100% of isolates susceptible to ceftriaxone). Several isolates were resistant to levofloxacin (6%), erythromycin (51%), and clindamycin (10%). The MIC90 for daptomycin was ≥ 4 μg/ml for G. adiacens and A. defectiva. G. elegans isolates were 100% susceptible to all antimicrobials tested, with the exception of erythromycin, to which only 20% were susceptible. This study provides antimicrobial susceptibility data for a recent collection of NVS and demonstrates important NVS species-related differences with respect to susceptibility to penicillin, cephalosporins, carbapenems, and daptomycin. Species-level identification of NVS organisms when susceptibility testing is not readily available may aid in treatment decisions.
Topics: Abiotrophia; Anti-Bacterial Agents; Carnobacteriaceae; Gram-Positive Bacterial Infections; Humans; Los Angeles; Microbial Sensitivity Tests; Molecular Typing; RNA, Ribosomal, 16S; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; beta-Lactams
PubMed: 26666926
DOI: 10.1128/AAC.02645-15 -
International Journal of Molecular... Aug 2021is a nutritionally variant streptococci that is found in the oral cavity, and it is an etiologic agent of infective endocarditis. We have previously reported the...
is a nutritionally variant streptococci that is found in the oral cavity, and it is an etiologic agent of infective endocarditis. We have previously reported the binding activity of to fibronectin and to human umbilical vein endothelial cells (HUVECs). However, the contribution of some adhesion factors on the binding properties has not been well delineated. In this study, we identified DnaK, a chaperon protein, as being one of the binding molecules of to fibronectin. Recombinant DnaK (rDnaK) bound immobilized fibronectin in a concentration-dependent manner, and anti-DnaK antiserum reduced the binding activity of with both fibronectin and HUVECs. Furthermore, DnaK were observed on the cell surfaces via immune-electroscopic analysis with anti-DnaK antiserum. Expression of IL-8, CCL2, ICAM-1, and VCAM-1 was upregulated with the rDnaK treatment in HUVECs. Furthermore, TNF-α secretion of THP-1 macrophages was also upregulated with the rDnaK. We observed these upregulations in rDnaK treated with polymyxin B, but not in the heat-treated rDnaK. The findings show that DnaK functions not only as an adhesin to HUVECs via the binding to fibronectin but also as a proinflammatory agent in the pathogenicity to cause infective endocarditis.
Topics: Abiotrophia; Bacterial Adhesion; Bacterial Proteins; Fibronectins; HSP70 Heat-Shock Proteins; Human Umbilical Vein Endothelial Cells; Humans; Inflammation
PubMed: 34445234
DOI: 10.3390/ijms22168528 -
Revista Chilena de Infectologia :... Apr 2016
Topics: Abiotrophia; Agar; Culture Media; Gram-Positive Bacterial Infections; Staphylococcus aureus
PubMed: 27314997
DOI: 10.4067/S0716-10182016000200009 -
Journal of Oral Microbiology 2024Abiotrophia defectiva, although infrequently occurring, is a notable cause of culture-negative infective endocarditis with limited research on its virulence. Associated...
BACKGROUND
Abiotrophia defectiva, although infrequently occurring, is a notable cause of culture-negative infective endocarditis with limited research on its virulence. Associated with oral infections such as dental caries, exploring its secretome may provide insights into virulence mechanisms. Our study aimed to analyze and characterize the secretome of A. defectiva strain CCUG 27639.
METHODS
Secretome of A. defectiva was prepared from broth cultures and subjected to mass spectrometry and proteomics for protein identification. Inflammatory potential of the secretome was assessed by ELISA.
RESULTS
Eighty-four proteins were identified, with diverse subcellular localizations predicted by PSORTb. Notably, 20 were cytoplasmic, 12 cytoplasmic membrane, 5 extracellular, and 9 cell wall-anchored proteins. Bioinformatics tools revealed 54 proteins secreted via the 'Sec' pathway and 8 via a non-classical pathway. Moonlighting functions were found in 23 proteins, with over 20 exhibiting potential virulence properties, including peroxiredoxin and oligopeptide ABC transporter substrate-binding protein. Gene Ontology and KEGG analyses categorized protein sequences in various pathways. STRING analysis revealed functional protein association networks. Cytokine profiling demonstrated significant proinflammatory cytokine release (IL-8, IL-1β, and CCL5) from human PBMCs.
CONCLUSIONS
Our study provides a comprehensive understanding of A. defectiva's secretome, laying the foundation for insights into its pathogenicity.
PubMed: 38352067
DOI: 10.1080/20002297.2024.2307067 -
European Journal of Case Reports in... 2023Infective endocarditis (IE) is a well-described infectious disease, one with increased morbidity and mortality being the third or fourth most common life-threatening...
UNLABELLED
Infective endocarditis (IE) is a well-described infectious disease, one with increased morbidity and mortality being the third or fourth most common life-threatening infection syndrome. is a non-motile, catalase negative, gram-positive coccus in a chain, which can be isolated from the oral cavity, intestinal, and genitourinary tracts. IE due to this agent is rare and associated with heart valve destruction, congestive heart failure, and high embolisation rates, these being the major mortality causes. We present a case of IE due to this agent, complicated with a stroke, and splenic and renal infarction, with the need for aortic valve replacement. This article highlights the gaps of knowledge left by the rarity of this disease, which range from its diagnosis to its treatment, and what we need to mitigate such gaps, supported with a case description of a successful treatment of this infection.
LEARNING POINTS
Infective endocarditis due to has usually an indolent course, but the embolisation potential is very high.The major causes of mortality with this species are congestive heart failure due to valve destruction and the presence of multiple emboli.Surgical intervention rates are high with , reaching 50% of cases.
PubMed: 36819655
DOI: 10.12890/2023_003702 -
Microbiology and Immunology Nov 2020Abiotrophia defectiva is a species of nutritionally variant streptococci that is found in human saliva and dental plaques and that has been associated with infective...
Abiotrophia defectiva adhere to saliva-coated hydroxyapatite beads via interactions between salivary proline-rich-proteins and bacterial glyceraldehyde-3-phosphate dehydrogenase.
Abiotrophia defectiva is a species of nutritionally variant streptococci that is found in human saliva and dental plaques and that has been associated with infective endocarditis. In our previous study, it was found that A. defectiva could bind specifically to saliva-coated hydroxyapatite beads (SHA). This study identified a cell surface component of A. defectiva that promotes adherence to SHA beads. The binding of A. defectiva to SHA was reduced in the presence of antibodies against human proline-rich protein (PRP); these results suggested that PRP may be a critical component mediating interactions between A. defectiva and the salivary pellicle. Two-dimensional gel electrophoresis of whole A. defectiva cells followed by Far-Western blotting was conducted by probing with synthetic peptides analogous to the binding region of PRP known as PRP-C. The results indicate that an A. defectiva protein of 37 kDa interacts with PRP-C. The results of amino-terminal sequencing of the adhesive A. defectiva protein revealed significant similarity to glyceraldehyde-3-phosphate dehydrogenase (GAPDH). Recombinant GAPDH bound to immobilized PRP-C in a dose-dependent manner and binding of A. defectiva to SHA or to PRP was reduced in the presence of anti-GAPDH antiserum. Western blotting or electron immunomicroscopic observations with anti-GAPDH antiserum revealed that this protein was expressed in both cytosolic and cell wall fractions. These results suggest that A. defectiva could specifically bind to PRP via interactions with cell surface GAPDH; the findings suggest a mechanism underlying A. defectiva-mediated adherence to saliva-coated tooth surfaces.
Topics: Abiotrophia; Amino Acid Sequence; Bacterial Adhesion; Durapatite; Escherichia coli; Glyceraldehyde-3-Phosphate Dehydrogenases; Humans; Peptides; Proline; Saliva; Salivary Proline-Rich Proteins; Streptococcus
PubMed: 32918493
DOI: 10.1111/1348-0421.12848 -
Antimicrobial Agents and Chemotherapy Aug 2016MICs of 25 Abiotrophia defectiva and 109 Granulicatella adiacens isolates were determined by broth microdilution. Using CLSI breakpoints, the susceptibilities of A....
MICs of 25 Abiotrophia defectiva and 109 Granulicatella adiacens isolates were determined by broth microdilution. Using CLSI breakpoints, the susceptibilities of A. defectiva and G. adiacens isolates were, respectively, 24% and 34% to penicillin, 92% and 22% to ceftriaxone, 48% and 3% to cefepime, 72% and 87% to meropenem, 92% and 10% to cefotaxime, 100% and 97% to levofloxacin, 92% and 80% to clindamycin, and 24% and 50% to erythromycin. All isolates were susceptible to vancomycin. In the penicillin-susceptible subgroup, all A. defectiva isolates were susceptible to ceftriaxone; however, 62% of G. adiacens isolates were ceftriaxone nonsusceptible.
Topics: Abiotrophia; Anti-Infective Agents; Carnobacteriaceae; Cefepime; Cefotaxime; Cephalosporins; Clindamycin; Erythromycin; Levofloxacin; Microbial Sensitivity Tests; Penicillins; Vancomycin
PubMed: 27216060
DOI: 10.1128/AAC.00485-16 -
Cureus Mar 2024A 67-year-old male with coronary artery disease and aortic stenosis after coronary artery bypass graft (CABG) and aortic valve replacement (AVR) presented after a...
A 67-year-old male with coronary artery disease and aortic stenosis after coronary artery bypass graft (CABG) and aortic valve replacement (AVR) presented after a two-day history of dizziness and frequent falls. Initially, he was found to have a subacute infarct of the left temporal lobe, osteomyelitis of the lumbar spine, and an aortic valve vegetation. Further investigations demonstrated gram-positive bacteremia, and, eventually, the causative organism was identified as . He was treated with penicillin and gentamicin in the inpatient setting and then discharged with outpatient intravenous (IV) ceftriaxone for the remainder of the four-week antibiotic course. He did not suffer complications after initiating therapy and recovered. We wish to raise awareness of the existence and complications that can result from endocarditis and encourage further research into effective antibiotic treatment. endocarditis may lead to neurological and orthopedic infective sequelae; understanding and awareness of spp. infections are important to ensure effective treatment of endocarditis.
PubMed: 38659565
DOI: 10.7759/cureus.56904 -
Journal of Oral Science Jan 2020Granulicatella adiacens (G. adiacens) and Abiotrophia defectiva (A. defectiva) colonize the oral cavity and form part of the normal flora in the intestinal and...
Contribution of different adherent properties of Granulicatella adiacens and Abiotrophia defectiva to their associations with oral colonization and the risk of infective endocarditis.
Granulicatella adiacens (G. adiacens) and Abiotrophia defectiva (A. defectiva) colonize the oral cavity and form part of the normal flora in the intestinal and genitourinary tracts. As reported previously, the frequency of isolation of G. adiacens from the oral cavity was much higher than that of A. defectiva. However, it has been reported that compared with G. adiacens, A. defectiva was isolated at considerably higher frequencies from the blood of patients with infective endocarditis (IE). Hence, in this study, the in vitro interaction of G. adiacens and A. defectiva strains with host surfaces and biofilm formation was examined to assess whether their different adhesive properties contribute to their associations with oral colonization and IE, respectively. G. adiacens exhibited an increased binding ability to saliva-coated hydroxyapatite beads than A. defectiva following the addition of CaCl. Furthermore, biofilm formation was observed only for G. adiacens with the use of a polystyrene tube and scanning electron microscopy analysis. Conversely, A. defectiva displayed significantly greater adherence to human umbilical vein endothelial cells and immobilized fibronectin than G. adiacens. These findings suggest that differences in binding properties to host components imply specific binding mechanisms in G. adiacens and A. defectiva, which might mediate selective colonization in the oral cavity or are associated with the pathogenicity of endocarditis.
Topics: Abiotrophia; Endocarditis, Bacterial; Endothelial Cells; Humans; Streptococcus
PubMed: 31708553
DOI: 10.2334/josnusd.19-0021 -
IDCases 2023Belonging to the normal oral, gastrointestinal, and urogenital flora, is responsible for 1-2 % of all infective endocarditis (IE) cases. The manifestation of...
Belonging to the normal oral, gastrointestinal, and urogenital flora, is responsible for 1-2 % of all infective endocarditis (IE) cases. The manifestation of endocarditis may by atypical, without fever. Difficult to isolate pathogen requires special culture media. A 45-year-old female was admitted due to anemia and progressive weight loss (8 kg in 6 months). She had a history of benign mitral valve (MV) prolapse and non-stenotic bicuspid aortic valve (BAV). In echocardiography, large vegetations on MV and small vegetation on BAV were found. An enriched medium for fastidious pathogens was used. was identified using biochemical analysis with VITEK-2 Compact. In the fourth week of antibiotic therapy, she required urgent MV replacement due to MV regurgitation progression while vegetation on BAV disappeared. Although patient's frailty and underweight caused prolonged postoperative wound healing, she was transferred to rehabilitation in good conditions. No relapse of IE was observed during five-month follow-up.
PubMed: 37867569
DOI: 10.1016/j.idcr.2023.e01906