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Frontiers in Cellular and Infection... 2014Streptococcus pyogenes is a significant pathogen of humans, annually causing over 700,000,000 infections and 500,000 deaths. Virulence in S. pyogenes is closely linked... (Review)
Review
Streptococcus pyogenes is a significant pathogen of humans, annually causing over 700,000,000 infections and 500,000 deaths. Virulence in S. pyogenes is closely linked to mobile genetic elements like phages and chromosomal islands (CI). S. pyogenes phage-like chromosomal islands (SpyCI) confer a complex mutator phenotype on their host. SpyCI integrate into the 5' end of DNA mismatch repair (MMR) gene mutL, which also disrupts downstream operon genes lmrP, ruvA, and tag. During early logarithmic growth, SpyCI excise from the bacterial chromosome and replicate as episomes, relieving the mutator phenotype. As growth slows and the cells enter stationary phase, SpyCI reintegrate into the chromosome, again silencing the MMR operon. This system creates a unique growth-dependent and reversible mutator phenotype. Additional CI using the identical attachment site in mutL have been identified in related species, including Streptococcus dysgalactiae subsp. equisimilis, Streptococcus anginosus, Streptococcus intermedius, Streptococcus parauberis, and Streptococcus canis. These CI have small genomes, which range from 13 to 20 kB, conserved integrase and DNA replication genes, and no identifiable genes encoding capsid proteins. SpyCI may employ a helper phage for packaging and dissemination in a fashion similar to the Staphylococcus aureus pathogenicity islands (SaPI). Outside of the core replication and integration genes, SpyCI and related CI show considerable diversity with the presence of many indels that may contribute to the host cell phenotype or fitness. SpyCI are a subset of a larger family of streptococcal CI who potentially regulate the expression of other host genes. The biological and phylogenetic analysis of streptococcal chromosomal islands provides important clues as to how these chromosomal islands help S. pyogenes and other streptococcal species persist in human populations in spite of antibiotic therapy and immune challenges.
Topics: Chromosomes, Bacterial; DNA Mismatch Repair; Evolution, Molecular; Genes, Bacterial; Genetic Variation; Genomic Islands; Humans; INDEL Mutation; Microbial Viability; Mutagenesis, Insertional; Mutation; Phenotype; Regulatory Sequences, Nucleic Acid; Streptococcus; Streptococcus pyogenes; Virulence
PubMed: 25161960
DOI: 10.3389/fcimb.2014.00109 -
Pathogens (Basel, Switzerland) Dec 2020Peri-implantitis is a steadily rising disease and is caused by oral bacterial pathogens able to form biofilm on implant surfaces and peri-implant tissues, making...
Peri-implantitis is a steadily rising disease and is caused by oral bacterial pathogens able to form biofilm on implant surfaces and peri-implant tissues, making antibiotics treatment less effective. The use of commercial probiotics against oral pathogens could serve as an alternative to prevent biofilm formation. is one of the early colonizers of biofilm formation in dental implants. The aim of this study was to model the interaction between and strain K12, a probiotic bacterium producing bacteriocins. was co-cultured with K12 in an in vitro model simulating the biofilm formation in a dental implant composed by a titanium cylinder system. Biofilm formation rate was assessed by Real-Time PCR quantification of bacterial count and expression levels of gene, used in response to cell density in the biofilm. Biofilm formation, bacteriocin production, expression patterns were found to be already expressed within the first 12 h. More importantly, K12 was able to counter the biofilm formation in a titanium cylinder under the tested condition. In conclusion, our dental implant model may be useful for exploring probiotic-pathogen interaction to find an alternative to antibiotics for peri-implantitis treatment.
PubMed: 33419248
DOI: 10.3390/pathogens9121069 -
Pathogens (Basel, Switzerland) Feb 2019(SI) is associated with prolonged hospitalization and low survival rates. The genetic mechanisms involved in brain abscess development and genome evolution in...
(SI) is associated with prolonged hospitalization and low survival rates. The genetic mechanisms involved in brain abscess development and genome evolution in comparison to other members of the group are understudied. We performed a whole-genome comparative analysis of an SI isolate, LAU_SINT, associated with brain abscess following sinusitis with all SI genomes in addition to and . Selective pressure on virulence factors, phages, pan-genome evolution and single-nucleotide polymorphism analysis were assessed. The structural details of the type seven secretion system (T7SS) was elucidated and compared with different organisms. and were both abundant and conserved. Nisin resistance determinants were found in 47% of the isolates. Pan-genome and SNPs-based analysis didn't reveal significant geo-patterns. Our results showed that two SC isolates were misidentified as SI. We propose the presence of four T7SS modules (I⁻IV) located on various genomic islands. We detected a variety of factors linked to metal ions binding on the GIs carrying T7SS. This is the first detailed report characterizing the T7SS and its link to nisin resistance and metal ions binding in SI. These and yet uncharacterized T7SS transmembrane proteins merit further studies and could represent potential therapeutic targets.
PubMed: 30781742
DOI: 10.3390/pathogens8010022 -
BMJ Case Reports Nov 2021We report a case of a 54-year-old immunocompetent male who had lung abscess secondary to that led to discitis by contiguous spread of infection. He initially presented...
We report a case of a 54-year-old immunocompetent male who had lung abscess secondary to that led to discitis by contiguous spread of infection. He initially presented with constant chest pain for 6 weeks that radiated to lower back, with no fever, chills or weight loss. He denied smoking cigarettes, alcohol use or any illicit drug. On investigation, a mass was identified on the posterior medial aspect of the right lower lobe with direct infiltration into right side of the T5-T6 vertebral bodies. Histopathology identified organising pneumonia with abscess. Tissue cultures showed , and were negative for other microorganisms. This case highlights a rare presentation of discitis by contiguous spread of infection from posterior right lower lobe lung abscess. usually occurs in older patients with pulmonary infections complicated with pleural effusion or lung abscess, but can present in young patients with no clear symptoms of lung infection, like our patient.
Topics: Aged; Discitis; Humans; Lung; Lung Abscess; Male; Middle Aged; Pleural Effusion; Streptococcus intermedius
PubMed: 34725064
DOI: 10.1136/bcr-2021-245675 -
Cell Stress & Chaperones Jan 2012Streptococcus intermedius is a facultatively anaerobic, opportunistic pathogen that causes purulent infections and abscess formation. The DnaK chaperone system has been...
Streptococcus intermedius is a facultatively anaerobic, opportunistic pathogen that causes purulent infections and abscess formation. The DnaK chaperone system has been characterized in several pathogenic bacteria and seems to have important functions in stress resistance and pathogenicity. However, the role of DnaK in S. intermedius remains unclear. Therefore, we constructed a dnaK knockout mutant that exhibited slow growth, thermosensitivity, accumulation of GroEL in the cell, and reduced cytotoxicity to HepG2 cells. The level of secretion of a major pathogenic factor, intermedilysin, was not affected by dnaK mutation. We further examined the function and property of the S. intermedius DnaK chaperone system by using Escherichia coli ΔdnaK and ΔrpoH mutant strains. S. intermedius DnaK could not complement the thermosensitivity of E. coli ΔdnaK mutant. However, the intact S. intermedius DnaK chaperone system could complement the thermosensitivity and acid sensitivity of E. coli ΔdnaK mutant. The S. intermedius DnaK chaperone system could regulate the activity and stability of the heat shock transcription factor σ(32) in E. coli, although S. intermedius does not utilize σ(32) for heat shock transcription. The S. intermedius DnaK chaperone system was also able to efficiently eliminate the aggregated proteins from ΔrpoH mutant cells. Overall, our data showed that the S. intermedius DnaK chaperone system has important functions in quality control of cellular proteins but has less participation in the modulation of expression of pathogenic factors.
Topics: Amino Acid Sequence; Bacterial Proteins; Bacteriocins; Chaperonin 60; Escherichia coli; Escherichia coli Proteins; Gene Knockout Techniques; HSP70 Heat-Shock Proteins; Hep G2 Cells; Humans; Molecular Chaperones; Molecular Sequence Data; Mutation; Sequence Alignment; Streptococcus intermedius; Stress, Physiological
PubMed: 21822788
DOI: 10.1007/s12192-011-0284-4 -
Cureus Apr 2021The group (SAG) consists of three bacteria (, , and ) that are known commensals of the upper respiratory, digestive, and reproductive tracts. While a rare occurrence,...
The group (SAG) consists of three bacteria (, , and ) that are known commensals of the upper respiratory, digestive, and reproductive tracts. While a rare occurrence, these bacteria have the capability of causing devastating pyogenic infections and ensuing abscess formations. It is often difficult to distinguish this group as a contaminant or the offending organism (as it is often cultured in respiratory specimens); therefore, it is important to understand the risk factors, clinical presentation, and diagnostic findings that can provide a more accurate picture to identify the organism. Published literature pertaining to the SAG group has rarely documented any invasive surgical intervention that was undertaken for treatment. We describe a case of a 59-year-old male who presented for persistent chest pain and profuse productive cough weeks after he was diagnosed with a left lower extremity deep vein thrombosis and right-sided pulmonary embolism. The patient was found to have a rapidly evolving right middle lobe lung abscess complicated by a right hemithorax empyema. Management included an exploration of the right chest, decortication, parietal pleurectomy, and partial excision of the right middle lobe. Subsequently, the patient completed four weeks of antibiotics with ertapenem.
PubMed: 34017651
DOI: 10.7759/cureus.14534 -
Scientifica 2023Dental caries, a predominant childhood and adolescence affliction, has numerous factors implicated in its pathogenesis. Electronic cigarettes (ECs) have recently gained... (Review)
Review
Dental caries, a predominant childhood and adolescence affliction, has numerous factors implicated in its pathogenesis. Electronic cigarettes (ECs) have recently gained popularity among the younger population. Various factors, such as the EC liquid composition and aerosols, are associated with the development of dental caries. This review explains numerous EC-related factors which may lead to dental caries. An electronic search was conducted in Medline (Pubmed), Scopus, and Embase databases to evaluate the original research investigating the role of ECs in developing dental caries. About 12 included studies in the review indicated that factors such as the composition of e-liquids and aerosols are significant in the progression of dental caries. Specifically, cariogenic sugars such as sucrose, fructose, glucose, aldehydes, and flavors such as menthol, cinnamon, and strawberry in the e-liquids contribute to dental caries. They are toxic to oral commensals such as , , , and and promote the proliferation of cariogenic pathogens such as () which causes dental caries. However, further validation of the effects of ECs on the development of dental caries is warranted through clinical trials.
PubMed: 37680743
DOI: 10.1155/2023/9980011 -
Case Reports in Infectious Diseases 2014Streptococcus intermedius is a member of the Streptococcus anginosus group of bacteria. This group is part of the normal flora of the oropharynx, genitourinary, and...
Streptococcus intermedius is a member of the Streptococcus anginosus group of bacteria. This group is part of the normal flora of the oropharynx, genitourinary, and gastrointestinal tracts; however, they have been known to cause a variety of purulent infections including meningitis, endocarditis, and abscesses, even in immunocompetent hosts. In particular, S. intermedius has been associated with the development of liver and brain abscesses. There have been several case reports of S. intermedius liver abscesses with active periodontal infection. To our knowledge, however, there has not been a case following a routine dental procedure. In fact, the development of liver abscesses secondary to dental procedures is very rare in general, and there are only a few case reports in the literature describing this in relation to any pathogen. We present a rare case of S. intermedius bacteremia and liver abscess following a dental cleaning. This case serves to further emphasize that even routine dental procedures can place a patient at risk of the development of bacteremia and liver abscesses. For this reason, the clinician must be sure to perform a detailed history and careful examination. Timely diagnosis of pyogenic liver abscesses is vital, as they are typically fatal if left untreated.
PubMed: 25197585
DOI: 10.1155/2014/954046 -
Infection and Immunity Sep 2017is an opportunistic bacterial pathogen secreting a human-specific cytolysin called intermedilysin (ILY) as a major pathogenic factor. This bacterium can degrade glycans...
is an opportunistic bacterial pathogen secreting a human-specific cytolysin called intermedilysin (ILY) as a major pathogenic factor. This bacterium can degrade glycans into monosaccharides using two glycosidases, multisubstrate glycosidase A (MsgA) and neuraminidase (NanA). Here, we detected a stronger hemolytic activity mediated by ILY when PC574 was cultured in fetal bovine serum (FBS) than when it was grown in the standard culture medium. FBS-cultured cells also showed higher MsgA and NanA activity, although overproduction of ILY in FBS was undetectable in mutants -null and -null. Addition of purified MsgA and NanA to the FBS resulted in a release of 2.8 mM galactose and 4.3 mM -acetylneuraminic acid; these sugar concentrations were sufficient to upregulate the expression of ILY, MsgA, and NanA. Conversely, when strain PC574 was cultured in human plasma, no similar increase in hemolytic activity was observed. Moreover, addition of human plasma to the culture in FBS appeared to inhibit the stimulatory effect of FBS on ILY, MsgA, and NanA, although there were individual differences among the plasma samples. We confirmed that human plasma contains immunoglobulins that can neutralize ILY, MsgA, and NanA activities. In addition, human plasma had a neutralizing effect on cytotoxicity of toward HepG2 cells in FBS, and a higher concentration of human plasma was necessary to reduce the cytotoxicity of an ILY-high-producing strain than an ILY-low-producing strain. Overall, our data show that blood contains factors that stimulate and inhibit ILY expression and activity, which may affect pathogenicity of .
Topics: Bacteriocins; Erythrocytes; Hep G2 Cells; Hepatocytes; Humans; Streptococcus intermedius; Virulence Factors
PubMed: 28607101
DOI: 10.1128/IAI.00379-17