-
Journal of Clinical Research in... Aug 2021Brain abscess formation is extremely rare in patients with osteopetrosis. Herein, we report a case of viridans streptococci brain abscess in an immunocompromised child...
Brain abscess formation is extremely rare in patients with osteopetrosis. Herein, we report a case of viridans streptococci brain abscess in an immunocompromised child diagnosed with osteopetrosis. The patient presented with a sudden change in mental status and convulsions. Radiological evaluation revealed a temporal lobe brain abscess, and intravenous antibiotherapy was started immediately. The patient underwent abscess drainage, and laboratory investigation of pus material revealed viridans streptococci.
Topics: Adolescent; Agammaglobulinemia; Anti-Bacterial Agents; Brain Abscess; Central Nervous System Bacterial Infections; Drainage; Humans; Immunocompromised Host; Male; Osteopetrosis; Risk Factors; Streptococcal Infections; Treatment Outcome; Viridans Streptococci
PubMed: 32840095
DOI: 10.4274/jcrpe.galenos.2020.2020.0039 -
Journal of Clinical Microbiology Jan 2006Clinical and microbiologic studies of 50 cases of viridans streptococcal bacteremia in cancer patients were performed. The bacteria were identified to species level by...
Clinical and microbiologic studies of 50 cases of viridans streptococcal bacteremia in cancer patients were performed. The bacteria were identified to species level by sequencing analysis of the 16S rRNA gene. At least nine Streptococcus spp. were found, including S. mitis (25 strains, 50.0% of 50); currently unnamed Streptococcus spp. (11 strains); S. parasanguis (five strains); S. anginosus (three strains); S. salivarius (two strains); and one strain each of S. gordonii, S. sanguis, S. sobrinus, and S. vestibularis. There were no S. oralis strains. Among 11 antibiotics of nine classes tested, no resistance to vancomycin, linezolid, or quinupristin-dalfopristin was seen. Resistance to penicillin (MIC, 4 to 12 mug/ml) was noted only among S. mitis strains (28.0%, 7/25) and not non-S. mitis strains (0/25) (P = 0.004). Significantly more S. mitis strains than non-S. mitis strains were resistant to fluoroquinolones and to > or =3 classes of antibiotics. Isolation of quinolone-resistant organisms was associated with the prior usage of quinolones (P = 0.002). Quantitative blood cultures showed that the strains resistant to levofloxacin or gatifloxacin were associated with higher colony counts than were their corresponding nonresistant strains. The young and elderly patients also had higher levels of bacteremia caused predominantly by S. mitis. Septic shock was present in 17 (34.0% of 50) patients, and 13 of those cases were caused by S. mitis (P = 0.007). These results suggest that S. mitis is the most common cause of viridans streptococcal bacteremia in cancer patients and is more resistant to antibiotics than other species.
Topics: Anti-Bacterial Agents; Bacteremia; Blood; Culture Media; Drug Resistance, Bacterial; Hematologic Neoplasms; Humans; Microbial Sensitivity Tests; RNA, Ribosomal, 16S; Streptococcal Infections; Viridans Streptococci
PubMed: 16390964
DOI: 10.1128/JCM.44.1.160-165.2006 -
BMC Microbiology Aug 2021Biofilms are microbial communities surrounded by a self-produced extracellular matrix which protects them from environmental stress. Bacteria within biofilms are 10- to...
BACKGROUND
Biofilms are microbial communities surrounded by a self-produced extracellular matrix which protects them from environmental stress. Bacteria within biofilms are 10- to 1000-fold more resistant to antibiotics, making it challenging but imperative to develop new therapeutics that can disperse biofilms and eradicate infection. Gram-negative bacteria produce outer membrane vesicles (OMV) that play critical roles in communication, genetic exchange, cargo delivery, and pathogenesis. We have previously shown that OMVs derived from Burkholderia thailandensis inhibit the growth of drug-sensitive and drug-resistant bacteria and fungi.
RESULTS
Here, we examine the antibiofilm activity of Burkholderia thailandensis OMVs against the oral biofilm-forming pathogen Streptococcus mutans. We demonstrate that OMV treatment reduces biofilm biomass, biofilm integrity, and bacterial cell viability. Both heat-labile and heat-stable components, including 4-hydroxy-3-methyl-2-(2-non-enyl)-quinoline and long-chain rhamnolipid, contribute to the antibiofilm activity of OMVs. When OMVs are co-administered with gentamicin, the efficacy of the antibiotic against S. mutans biofilms is enhanced.
CONCLUSION
These studies indicate that bacterial-derived OMVs are highly effective biological nanoparticles that can inhibit and potentially eradicate biofilms.
Topics: Anti-Bacterial Agents; Bacterial Outer Membrane; Biofilms; Extracellular Vesicles; Gentamicins; Microbial Sensitivity Tests; Streptococcus mutans
PubMed: 34429066
DOI: 10.1186/s12866-021-02296-x -
Frontiers in Cellular and Infection... 2020Differentiation between mitis group streptococci (MGS) bacteria in routine laboratory tests has become important for obtaining accurate epidemiological information on...
Differentiation between mitis group streptococci (MGS) bacteria in routine laboratory tests has become important for obtaining accurate epidemiological information on the characteristics of MGS and understanding their clinical significance. The most reliable method of MGS species identification is multilocus sequence analysis (MLSA) with seven house-keeping genes; however, because this method is time-consuming, it is deemed unsuitable for use in most clinical laboratories. In this study, we established a scheme for identifying 12 species of MGS () using the MinION nanopore sequencer (Oxford Nanopore Technologies, Oxford, UK) with the taxonomic aligner "What's in My Pot?" (WIMP; Oxford Nanopore's cloud-based analysis platform) and Kraken2 pipeline with the custom database adjusted for MGS species identification. The identities of the species in reference genomes ( = 514), clinical isolates ( = 31), and reference strains ( = 4) were confirmed via MLSA. The nanopore simulation reads were generated from reference genomes, and the optimal cut-off values for MGS species identification were determined. For 31 clinical isolates ( = 8, = 17 and = 6) and 4 reference strains ( = 1, = 1, = 1, and = 1), a sequence library was constructed via a Rapid Barcoding Sequencing Kit for multiplex and real-time MinION sequencing. The optimal cut-off values for the identification of MGS species for analysis by WIMP and Kraken2 pipeline were determined. The workflow using Kraken2 pipeline with a custom database identified all 12 species of MGS, and WIMP identified 8 MGS bacteria except , and . The results obtained by MinION with WIMP and Kraken2 pipeline were consistent with the MGS species identified by MLSA analysis. The practical advantage of whole genome analysis using the MinION nanopore sequencer is that it can aid in MGS surveillance. We concluded that MinION sequencing with the taxonomic aligner enables accurate MGS species identification and could contribute to further epidemiological surveys.
Topics: Bacterial Typing Techniques; Genes, Bacterial; Genome, Bacterial; Humans; Mouth Mucosa; Multilocus Sequence Typing; Nanopore Sequencing; Phylogeny; Sequence Analysis, DNA; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Streptococcal Infections; Streptococcus; Streptococcus mitis; Streptococcus oralis; Streptococcus pneumoniae; Streptococcus sanguis; Whole Genome Sequencing
PubMed: 32083020
DOI: 10.3389/fcimb.2020.00011 -
Frontiers in Cellular and Infection... 2019subspecies is explored as an anti-cariogenic probiotic. Here, subjecting freshly stimulated saliva samples of 35 healthy volunteers, six epidemiologically unrelated...
subspecies is explored as an anti-cariogenic probiotic. Here, subjecting freshly stimulated saliva samples of 35 healthy volunteers, six epidemiologically unrelated and two related strains were isolated (prevalence around 20%) applying a newly developed three-step procedure. Furthermore, the probiotic strain 7746 (AB-Dentisanium®) was tested under a variety of environmental conditions for its inhibitory effect on six , two , 15 other oral or intestinal streptococci, 15 strains, and six representatives of other species including periodontopathogens. All except one of the strains were inhibited by 7746 colonies or culture supernatant concentrate but only if either the test cell number was low or the producer or its bacteriocin concentration, respectively, was high. OMI 332, OMI 315, OMI 335, OMI 238, and the intestinal OMI 339 were not inhibited, while the other 10 streptococcal strains (especially OMI 334 and intestinal OMI 326) showed a certain degree of inhibition. From the panel of other bacterial species only was slightly inhibited. With the exception of OMI 285 and OMI 291 that possessed a 7746 bacteriocin-like gene cluster, all strains and especially type strain 7747 were strongly inhibited by 7746. In conclusion, probiotic strain 7746 might antagonize the initiation and progression of dental caries by reducing if not too abundant. strains inhibit each other, but strains with similar bacteriocin-related gene clusters, including immunity genes, are able to co-exist due to cross-resistance. In addition, development of resistance and adaptation to 7746-bacteriocins was observed during our study and needs attention. Hence, mechanisms underlying such processes need to be further investigated using omics-approaches. On the manufacturing level, probiotic strains should be continuously tested for function. Further clinical studies investigating inhibition of by AB-Dentisanium® are required that should also monitor the impact on the oral microbiome composition including resident strains.
Topics: Aggregatibacter actinomycetemcomitans; Anti-Bacterial Agents; Antibiosis; Bacterial Typing Techniques; Bacteriocins; Carrier State; Healthy Volunteers; Prevalence; Probiotics; Streptococcal Infections; Streptococcus mutans; Streptococcus oralis; Streptococcus sobrinus
PubMed: 31041198
DOI: 10.3389/fcimb.2019.00110 -
The Kurume Medical Journal Nov 2023We report a case of Streptococcus mitis endocarditis associated with early gastric carcinoma. A 71-year-old man who had been diagnosed with aortic regurgitation (AR) two...
We report a case of Streptococcus mitis endocarditis associated with early gastric carcinoma. A 71-year-old man who had been diagnosed with aortic regurgitation (AR) two years previously was referred for valve surgery and evaluation of elevated inflammatory markers. Four months previously, atrophic gastritis, early gastric adenocarcinoma, and colon polyp had been identified in the patient during endoscopy. However, Helicobacter pylori testing was negative. On admission, he had no dental diseases or recent oral procedures. Echocardiography demonstrated severe AR and mobile vegetation on the aortic valve. Magnetic resonance imaging revealed cerebral embolism and spondylodiscitis. Blood cultures grew Streptococcus mitis. At surgery, destruction of the left cusp with vegetation and a perforation of the non-coronary cusp were found; in addition, aortic valve replacement was performed. Although the association between Streptococcus bovis bacteremia and colon neoplasm is well recognized, the association between Streptococcus mitis endocarditis and gastrointestinal carcinoma should also be kept in mind.
Topics: Male; Humans; Aged; Endocarditis, Bacterial; Streptococcus mitis; Streptococcal Infections; Carcinoma
PubMed: 37544751
DOI: 10.2739/kurumemedj.MS6912003 -
Frontiers in Cellular and Infection... 2020is an oral species closely associated with dental caries. As an early oral colonizer, utilizes interspecies coaggregation to promote the colonization of subsequent...
is an oral species closely associated with dental caries. As an early oral colonizer, utilizes interspecies coaggregation to promote the colonization of subsequent species and affect polymicrobial pathogenesis. Previous studies have confirmed several adhering partner species of , including and . In this study, we discovered new intergeneric co-adherence between and the saliva isolate (GBS-SI101). Research shows that GBS typically colonizes the human gastrointestinal and vaginal tracts. It is responsible for adverse pregnancy outcomes and life-threatening infections in neonates and immunocompromised people. Our results revealed that GtfB and GtfC of , which contributed to extracellular polysaccharide synthesis, promoted coaggregation of with GBS-SI101. In addition, oral streptococci, including and , barely inhibited the growth of GBS-SI101. This study indicated that could help GBS integrate into the associated oral polymicrobial community and become a resident species in the oral cavity, increasing the risk of oral infections.
Topics: Biofilms; Dental Caries; Humans; Infant, Newborn; Streptococcus agalactiae; Streptococcus mutans; Streptococcus sanguis
PubMed: 32733820
DOI: 10.3389/fcimb.2020.00344 -
Journal of Clinical Microbiology Jun 1999From January 1995 to May 1998, 57 episodes of bacteremia due to viridans group streptococci were identified in 50 febrile neutropenic patients with hematologic...
From January 1995 to May 1998, 57 episodes of bacteremia due to viridans group streptococci were identified in 50 febrile neutropenic patients with hematologic malignancies. Four patients experienced two separate episodes of streptococcal bacteremia, and one patient had four separate episodes of streptococcal bacteremia. Strains were identified to species level as Streptococcus mitis (n = 37), Streptococcus oralis (n = 19), and Streptococcus salivarius (n = 1). Epidemiologic relatedness of these strains was studied by using PCR-based fingerprinting with M13 and ERIC-2 primers and pulsed-field gel electrophoresis with restriction enzyme SmaI. All strains that were isolated from different patients exhibited unique fingerprint patterns, thus suggesting that viridans group streptococcal bacteremia usually derives from an endogenous source. Cross-transmission of strains between patients could not be established. Four S. mitis isolates recovered during four separate bacteremic episodes in a single patient had identical fingerprint patterns. Susceptibility testing was carried out by broth microdilution technique according to National Committee for Clinical Laboratory Standards guidelines. The MICs at which 90% of the isolates are inhibited were (in milligrams per liter) as follows: 0. 5 (penicillin), 0.5 (amoxicillin), 0.25 (cefotaxime), 2 (chloramphenicol), 4 (erythromycin), 0.5 (clindamycin), >/=32 (tetracycline), >/=32 (trimethoprim-sulfamethoxazole), 4 (ciprofloxacin), 0.5 (sparfloxacin), 0.5 (vancomycin), 0.25 (teicoplanin), and 1 (quinupristin-dalfopristin). High-level penicillin resistance (MIC, >/=4 mg/liter) was found in one isolate only, but intermediate penicillin resistance was noted in 11 isolates (19%). Resistance rates to other drugs were as follows: 7% (amoxicillin), 4% (cefotaxime), 4% (chloramphenicol), 32% (erythromycin), 9% (clindamycin), 39% (tetracycline), 68% (trimethoprim-sulfamethoxazole), 23% (ciprofloxacin), 0% (sparfloxacin), 0% (vancomycin), 0% (teicoplanin), and 0% (quinupristin-dalfopristin).
Topics: Adolescent; Adult; Aged; Anti-Bacterial Agents; Bacteremia; Child; Child, Preschool; Hematologic Neoplasms; Humans; Microbial Sensitivity Tests; Middle Aged; Molecular Epidemiology; Neutropenia; Random Amplified Polymorphic DNA Technique; Streptococcal Infections; Streptococcus; Streptococcus oralis
PubMed: 10325340
DOI: 10.1128/JCM.37.6.1876-1880.1999 -
Clinical Microbiology and Infection :... Nov 2013Accurate species-level identification of alpha-hemolytic (viridans) streptococci (VGS) is very important for understanding their pathogenicity and virulence. However, an...
Accurate species-level identification of alpha-hemolytic (viridans) streptococci (VGS) is very important for understanding their pathogenicity and virulence. However, an extremely high level of similarity between VGS within the mitis group (S. pneumoniae, S. mitis, S. oralis and S. pseudopneumoniae) often results in misidentification of these organisms. Earlier, matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) has been suggested as a tool for the rapid identification of S. pneumoniae. However, by using Biotyper 3.0 (Bruker) or Vitek MS (bioMérieux) databases, Streptococcus mitis/oralis species can be erroneously identified as S. pneumoniae. ClinProTools 2.1 software was used for the discrimination of MALDI-TOF mass spectra of 25 S. pneumoniae isolates, 34 S. mitis and three S. oralis. Phenotypical tests and multilocus gene typing schemes for the S. pneumoniae (http://spneumoniae.mlst.net/) and viridans streptococci (http://viridans.emlsa.net/) were used for the identification of isolates included in the study. The classifying model was generated based on different algorithms (Genetic Algorithm, Supervised Neural Network and QuickClassifier). In all cases, values of sensitivity and specificity were found to be equal or close to 100%, allowing discrimination of mass spectra of different species. Three peaks (6949, 9876 and 9975 m/z) were determined conferring the maximal statistical weight onto each model built. We find this approach to be promising for viridans streptococci discrimination.
Topics: Algorithms; Bacteriological Techniques; Sensitivity and Specificity; Software; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Streptococcus mitis; Streptococcus pneumoniae
PubMed: 23331578
DOI: 10.1111/1469-0691.12113 -
Microbiology and Immunology Dec 2021The performance of the ASTA MicroIDSys system (ASTA), a new matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) system, was...
Performance assessment of ASTA MicroIDSys, a new matrix assisted laser desorption ionization-time of flight mass spectrometry system, for identification of viridans group streptococci.
The performance of the ASTA MicroIDSys system (ASTA), a new matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) system, was evaluated for the identification of viridans group streptococci (VGS) and compared with the results obtained with the Bruker Biotyper system (Bruker Daltonics). A total of 106 Streptococcus reference strains belonging to 24 species from the bacterial strain bank was analyzed using the two MALDI-TOF MS systems. Of the 106 reference strains tested, ASTA MicroIDSys and Bruker Biotyper correctly identified 84.9% and 81.1% at the species level, 100% and 97.2% at the group level and 100% and 98.1% at the genus level, respectively. The difference between the two systems was not statistically significant (P = 0.289). Out of 24 species, 13 species were accurately identified to the species level with 100% accurate identification rates with both systems. The accurate identification rates at the species level of ASTA MicroIDSys and Bruker Biotyper were 100% and 87.5% for the S. anginosus group; 78.4% and 73.5% for the S. mitis group; 91.7% and 91.7% for the S. mutans group; and 100% and 100% for the S. salivarius group, respectively. The ASTA MicroIDSys showed an identification performance equivalent to that of the Bruker Biotyper for VGS. Therefore, it would be useful for the identification of VGS strains in clinical microbiology laboratories.
Topics: Bacteria; Lasers; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Viridans Streptococci
PubMed: 34516008
DOI: 10.1111/1348-0421.12942