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Microbiology Spectrum Aug 2023Streptococcus gallolyticus subsp. () is an opportunistic bacterial pathogen strongly associated with colorectal cancer. Here, through comparative genomics analysis, we...
Streptococcus gallolyticus subsp. () is an opportunistic bacterial pathogen strongly associated with colorectal cancer. Here, through comparative genomics analysis, we demonstrated that the genetic locus encoding the type VIIb secretion system (T7SSb) machinery is uniquely present in in two different arrangements. UCN34 carrying the most prevalent T7SSb genetic arrangement was chosen as the reference strain. To identify the effectors secreted by this secretion system, we inactivated the gene encoding the motor of this machinery. A comparison of the proteins secreted by UCN34 wild type and its isogenic Δ mutant revealed six T7SSb effector proteins, including the expected WXG effector EsxA and three LXG-containing proteins. In this work, we characterized an LXG-family toxin named herein TelE promoting the loss of membrane integrity. Seven homologs of TelE harboring a conserved glycine zipper motif at the C terminus were identified in different isolates. Scanning mutagenesis of this motif showed that the glycine residue at position 470 was crucial for TelE membrane destabilization activity. TelE activity was antagonized by a small protein TipE belonging to the DUF5085 family. Overall, we report herein a unique T7SSb effector exhibiting a toxic activity against nonimmune bacteria. In this study, 38 clinical isolates of Streptococcus gallolyticus subsp. () were sequenced and a genetic locus encoding the type VIIb secretion system (T7SSb) was found conserved and absent from 16 genomes of the closely related S. gallolyticus subsp. (). The T7SSb is a bona fide pathogenicity island. Here, we report that the model organism strain UCN34 secretes six T7SSb effectors. One of the six effectors named TelE displayed a strong toxicity when overexpressed in Escherichia coli. Our results indicate that TelE is probably a pore-forming toxin whose activity can be antagonized by a specific immunity protein named TipE. Overall, we report a unique toxin-immunity protein pair and our data expand the range of effectors secreted through T7SSb.
Topics: Streptococcus gallolyticus subspecies gallolyticus; Amino Acid Motifs; Glycine; Type VII Secretion Systems
PubMed: 37432124
DOI: 10.1128/spectrum.01481-23 -
Pediatrics International : Official... 2023
Topics: Humans; Streptococcus gallolyticus; Streptococcus; Endocarditis; Endocarditis, Bacterial; Streptococcal Infections
PubMed: 37428856
DOI: 10.1111/ped.15584 -
Cureus Jun 2023We present the case of a 71-year-old female with a history of surgical bioprosthetic aortic valve replacement who developed a liquefactive abscess near the mitral valve...
We present the case of a 71-year-old female with a history of surgical bioprosthetic aortic valve replacement who developed a liquefactive abscess near the mitral valve trigone following Streptococcus gallolyticus bacteremia. The patient initially presented with dyspnea and symptoms of an upper respiratory tract infection. A trans-esophageal echocardiogram revealed mitral valve vegetation and a possible source of sepsis near the prosthetic aortic valve. However, it was the identification of multiple silent dental abscesses during a routine dental check-up that led to the resolution of the patient's symptoms and the eradication of the infectious process. This case highlights the importance of considering dental infections as a potential cause of recurrent bacteremia and infectious complications in patients with prosthetic heart valves.
PubMed: 37425519
DOI: 10.7759/cureus.40073 -
Genes May 2023(1) Background: Piglet diarrhea is one of the most serious diseases in pigs and has brought great economic losses to the pig industry. Alteration of the gut microbiota...
(1) Background: Piglet diarrhea is one of the most serious diseases in pigs and has brought great economic losses to the pig industry. Alteration of the gut microbiota is an important factor in the etiology of piglet diarrhea. Therefore, this study aimed to analyze the differences in the gut microbial structures and fecal metabolic profile between post-weaning diarrhea and healthy Chinese Wannan Black pigs. (2) Methods: An integrated approach of 16S rRNA gene sequencing combined with LC/MS-based metabolomics was employed in this study. (3) Results: We found an increase in the relative abundance of the bacterial genus and a decrease in phylum Bacteroidetes and the species subsp. in piglet diarrhea. Meanwhile, obvious changes in the fecal metabolic profile of diarrheic piglets were also detected, particularly higher levels of polyamines (spermine and spermidine). Moreover, there were substantial associations between the disturbed gut microbiota and the altered fecal metabolites, especially a strong positive relationship between spermidine and . (4) Conclusions: These observations may provide novel insights into potential etiologies related to post-weaning diarrhea and further enhance our understanding of the role of gut microbiota in host homeostasis and in modulating gut microbial structure.
Topics: Animals; Swine; RNA, Ribosomal, 16S; Spermidine; Feces; Diarrhea; Metabolome
PubMed: 37372346
DOI: 10.3390/genes14061166 -
Digestive Diseases and Sciences Aug 2023Streptococcus gallolyticus subspecies gallolyticus (SGG) and Fusobacterium (F.) nucleatum have been implicated in colorectal carcinogenesis. Here, the association of...
BACKGROUND
Streptococcus gallolyticus subspecies gallolyticus (SGG) and Fusobacterium (F.) nucleatum have been implicated in colorectal carcinogenesis. Here, the association of immune responses to bacterial exposure with advancing stages of colorectal neoplasia was assessed by multiplex serology.
METHODS
Immunoglobulin (Ig) A and G antibody responses to eleven proteins each of F. nucleatum and SGG were measured in plasma of controls (n = 100) and patients with colorectal cancer (CRC, n = 25), advanced adenoma (n = 82), or small polyps (n = 85). Multivariable logistic regression was used to evaluate the association of bacterial sero-positivity with colorectal neoplasia. In a cohort subset with matched data (n = 45), F. nucleatum sero-positivity was correlated with bacterial abundance in both neoplastic and matched normal tissue.
RESULTS
IgG sero-positivity to Fn1426 of F. nucleatum was associated with an increased CRC risk (OR = 4.84; 95% CI 1.46-16.0), while IgA sero-positivity to any SGG protein or specifically Gallo0272 and Gallo1675 alone was associated with increased advanced adenoma occurrence (OR = 2.02, 95% CI 1.10-3.71; OR = 2.67, 95% CI 1.10-6.46; and OR = 6.17, 95% CI 1.61-23.5, respectively). Only F. nucleatum abundance in the normal mucosa positively correlated with the IgA response to the Fn1426 antigen (Correlation coefficient (r) = 0.38, p < 0.01).
CONCLUSION
Antibody responses to SGG and F. nucleatum were associated with occurrence of colorectal adenomas and CRC, respectively. Further studies are needed to clarify the role these microbes or the immune response to their antigens may have in colorectal carcinogenesis stages.
Topics: Humans; Fusobacterium nucleatum; Streptococcus gallolyticus; Antibody Formation; Colorectal Neoplasms; Bacteria; Adenoma; Carcinogenesis; Fusobacterium Infections
PubMed: 37338617
DOI: 10.1007/s10620-023-08001-4 -
Microbiology Spectrum Aug 2023This study aimed to identify which streptococcal species are closely associated with infective endocarditis (IE) and to evaluate risk factors for mortality in patients...
This study aimed to identify which streptococcal species are closely associated with infective endocarditis (IE) and to evaluate risk factors for mortality in patients with streptococcal IE. We performed a retrospective cohort study of all patients with streptococcal bloodstream infection (BSI) from January 2010 to June 2020 in a tertiary hospital in South Korea. We compared clinical and microbiological characteristics of streptococcal BSIs according to the diagnosis of IE. We performed multivariate analysis to evaluate the risk of IE according to streptococcal species and risk factors for mortality in streptococcal IE. A total of 2,737 patients were identified during the study period, and 174 (6.4%) were diagnosed with IE. The highest IE prevalence was in patients with Streptococcus mutans BSI (33% [9/27]) followed by S. sanguinis (31% [20/64]), S. gordonii (23% [5/22]), S. gallolyticus (16% [12/77]), and S. oralis (12% [14/115]). In multivariate analysis, previous IE, high-grade BSI, native valve disease, prosthetic valve, congenital heart disease, and community-onset BSI were independent risk factors for IE. After adjusting for these factors, S. sanguinis (adjusted OR [aOR], 7.75), S. mutans (aOR, 5.50), and S. gallolyticus (aOR, 2.57) were significantly associated with higher risk of IE, whereas S. pneumoniae (aOR, 0.23) and (aOR, 0.37) were associated with lower risk of IE. Age, hospital-acquired BSI, ischemic heart disease, and chronic kidney disease were independent risk factors for mortality in streptococcal IE. Our study points to significant differences in the prevalence of IE in streptococcal BSI according to species. Our study of risk of infective endocarditis in patients with streptococcal bloodstream infection demonstrated that Streptococcus sanguinis, S. mutans, and S. gallolyticus were significantly associated with higher risk of infective endocarditis. However, when we evaluated the performance of echocardiography in patients with streptococcal bloodstream infection, patients with S. mutans and S. gordonii bloodstream infection had a tendency of low performance in echocardiography. There are significant differences in the prevalence of infective endocarditis in streptococcal bloodstream infection according to species. Therefore, performing echocardiography in streptococcal bloodstream infection with a high prevalence of, and significant association with, infective endocarditis is desirable.
Topics: Humans; Retrospective Studies; Streptococcus; Endocarditis, Bacterial; Endocarditis; Streptococcal Infections; Sepsis
PubMed: 37284757
DOI: 10.1128/spectrum.01049-23 -
The Medical Journal of Malaysia May 2023World Health Organization (2019) has declared colorectal cancer (CRC) as the second most common cancer in females and third in males, where the incidence seems to rise...
INTRODUCTION
World Health Organization (2019) has declared colorectal cancer (CRC) as the second most common cancer in females and third in males, where the incidence seems to rise year by year. One of the very few potential pathogens specifically associated with malignant colonic diseases is Streptococcus gallolyticus (Sg). Sg is a part of the intestinal flora which formerly known as biotype I of Streptococcus bovis, belongs to Group D streptococci. Owing to only a few researches done in determining evidence to support Sg as a determinant of CRC, a systematic review is constructed.
MATERIALS AND METHODS
Full-text articles on case-control and cohort studies published from 1st January 2010 to 1st October 2020 were searched using Google Scholar, PubMed and JSTOR. People of all age groups and Sg bacteraemia or colonisation were the type of participant and exposure used for the search strategy, respectively. Data collection was done by three reviewers and checked by two reviewers for discrepancies. All the papers were critically appraised using the STROBE statement. Qualitative synthesis was done by descriptive comparison, distribution of Sg according to stage comparison, method used for Sg detection comparison and risk of bias comparison.
RESULT
Seven out of 11 articles that fulfil the eligibility criteria were selected. Four papers have low overall risk of bias due to low confounding or selection bias. Sg is found to be a risk factor for CRC from three papers studied, whereas the other four papers did not include the strength of association. Only two papers studied the association between the distribution of Sg and stages of CRC, where the results were contradictory from each other, making it to be inconclusive. The most common method used for Sg detection is a culturing technique, followed by molecular and biochemical techniques.
CONCLUSION
There is insufficient evidence to prove the association between Sg bacteraemia as the risk factor for CRC as well as the association between the Sg distribution and stages of CRC. Culturing technique is the most common method used for the detection of bacteria, but it requires subsequent investigations to confirm the presence of Sg. Thus, it is recommended that more studies need to be done using strong statistical analysis to control for most of the confounders with comprehensive explanation and use of more methods in the detection of Sg.
Topics: Male; Female; Humans; Streptococcus gallolyticus; Colorectal Neoplasms; Bacteremia
PubMed: 37271851
DOI: No ID Found -
Infectious Diseases (London, England) Jul 2023long term suppressive antibiotic treatment may be the only feasible option for patients with infective endocarditis (IE) not suitable for surgery.
INTRODUCTION
long term suppressive antibiotic treatment may be the only feasible option for patients with infective endocarditis (IE) not suitable for surgery.
CASE REPORTS
we present three cases of prosthetic valve endocarditis (PVE) caused by and which could not undergo surgical intervention due to high risk. Despite this, patients were successfully managed only by medical approach. Following intravenous targeted antimicrobial therapy, patients received chronic suppressive antimicrobial therapy (SAT) for at least twelve months with oral amoxicillin. In all cases, no further febrile episodes nor bacteraemia were observed and in two cases a complete positron emission tomography (PET) response was achieved. Due to uncertainty about antimicrobial exposure during oral SAT, serum bactericidal titres (SBTs) were obtained and compared to those obtained during parenteral therapy.
CONCLUSIONS
long term oral amoxicillin was effective and well-tolerated. SBTs after switch to oral therapy were quite heterogeneous, in some cases not reaching the conventionally established titre to assess bactericidal effect (1:8).Key pointsendovascular infection in non-suitable-for-surgery patients can be managed with long-term oral suppressive therapy.serum bactericidal assay confirmed high effectiveness of parenteral antibiotic therapy.serum bactericidal assay showed highly variable titres during oral therapy.
Topics: Humans; Endocarditis, Bacterial; Anti-Bacterial Agents; Heart Valve Prosthesis; Tomography, X-Ray Computed; Endocarditis; Anti-Infective Agents; Amoxicillin
PubMed: 37264877
DOI: 10.1080/23744235.2023.2216271 -
Internal Medicine (Tokyo, Japan) Jan 2024Bacterial meningitis is a life-threatening condition that is mainly caused by Streptococcus pneumoniae and Neisseria meningitis. Although Streptococcus gallolyticus...
Bacterial meningitis is a life-threatening condition that is mainly caused by Streptococcus pneumoniae and Neisseria meningitis. Although Streptococcus gallolyticus subsp. pasteurianus (Sgp) is also known to cause meningitis, its frequency is quite low, especially in adults. We herein report the first immunocompetent Japanese adult patient (20-year-old woman) with bacterial meningitis caused by Sgp. The patient showed dramatic improvement after antibiotic treatment. Although previous reports have described an association between Sgp infection and an immunosuppressive status, bowel and hepatobiliary diseases, or strongyloidiasis, our case did not demonstrate any of these conditions, suggesting that Sgp can cause meningitis even in young immunocompetent adults.
Topics: Female; Humans; Young Adult; Adult; Streptococcus gallolyticus; Streptococcal Infections; Streptococcus; Meningitis, Bacterial
PubMed: 37258163
DOI: 10.2169/internalmedicine.1785-23 -
Current Microbiology May 2023Recently, the phenomenon of infection of humans as hosts by animal pathogens has been increasing. Streptococcus is an example of a genus in which bacteria overcome the...
Recently, the phenomenon of infection of humans as hosts by animal pathogens has been increasing. Streptococcus is an example of a genus in which bacteria overcome the species barrier. Therefore, monitoring infections caused by new species of human pathogens is critical to their spread. Seventy-five isolates belonging to streptococcal species that have recently been reported as a cause of human infections with varying frequency, were tested. The aim of the study was to determine the drug resistance profiles of the tested strains, the occurrence of resistance genes and genes encoding the most important streptococcal virulence factors. All tested isolates retained sensitivity to β-lactam antibiotics. Resistance to tetracyclines occurred in 56% of the tested strains. We have detected the MLS type resistance (cross-resistance to macrolide, lincosamide, and streptogramin B) in 20% of the tested strains. 99% of the strains had tetracycline resistance genes. The erm class genes encoding MLS resistance were present in 47% of strains. Among the strains with MLS resistance, 92% had the streptokinase gene, 58% the streptolysin O gene and 33% the streptolysin S gene. The most extensive resistance concerned isolates that accumulated the most traits and genes, both resistance genes and virulence genes, increasing their pathogenic potential. Among the tested strains, the gene encoding streptokinase was the most common. The results of the prove that bacteria of the species S. uberis, S. dysgalactiae and S. gallolyticus are characterized by a high pathogenic potential and can pose a significant threat in case of infection of the human body.
Topics: Animals; Humans; Anti-Bacterial Agents; Drug Resistance, Bacterial; Lincosamides; Streptococcus; Genotype; Microbial Sensitivity Tests; Streptococcal Infections
PubMed: 37256427
DOI: 10.1007/s00284-023-03337-6