Case of aortic endocarditis caused by Lactobacillus casei

Zé-Zé, Líbia

doi:10.1099/jmm.0.05328-0

Cited by 28 publications

(14 citation statements)

References 20 publications

(22 reference statements)

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“…L. casei induced a pattern of phenotypic changes on monocytes similar to those of the five oral streptococcal isolates examined in this study. Interestingly, L. casei has also been identified in infected endocardial vegetation where it can serve as a pathogen (39,40).…”

Section: Discussionmentioning

confidence: 99%

Endocarditis-Associated Oral Streptococci Promote Rapid Differentiation of Monocytes into Mature Dendritic Cells

2005

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Endocarditis is frequently attributable to oral streptococci, but mechanisms of pathogenesis are not well understood, although monocytes appear to be important. High titers of interleukin-12 (IL-12) are produced by peripheral blood mononuclear cells (PBMC) after engaging Streptococcus mutans, but monocytes in developing endocardial vegetations tend to disappear rather than become macrophages. These data prompted the hypothesis that streptococcus-infected monocytes differentiate into short-lived IL-12-producing dendritic cells (DCs) rather than macrophages. PBMC from healthy subjects were stimulated with six isolates of oral streptococci, three nonstreptococcal oral bacteria, or IL-4 plus granulocyte-macrophage colony-stimulating factor, and the appearance of cells with markers typical of mature DCs (CD83 ؉ , CD86 ؉ , CD11c ؉ , and CD14 ؊ ) was monitored. Supernatant fluids from the PBMC cultures were harvested and IL-12 p70 levels were determined. S. mutans-stimulated monocytes were analyzed for their ability to elicit allogeneic mixed-lymphocyte reactions. All streptococci examined, except one strain of Streptococcus oralis (35037), rapidly induced up-regulation of CD83 and CD86 and a loss of CD14 in the CD11c؉ monocyte population within 20 h. Induction of IL-12 was CD14 dependent and correlated with streptococcal isolates that promoted the DC phenotype. Major histocompatibility complex (MHC) class II expression was up-regulated by S. mutans, and these cells were short-lived and elicited potent allogeneic mixed-lymphocyte reactions typical of DCs. In summary, monocytes stimulated with endocarditis-associated oral streptococci rapidly exhibited the DC phenotype and functions. These data suggest that the initiation of bacterial endocarditis by oral streptococci may involve monocyte-to-DC differentiation, and this may help explain the low levels of macrophages in the site.Viridans group streptococci are the most common cause of native valve endocarditis, accounting for 45 to 80% of cases, and Streptococcus sanguis, Streptococcus mutans, Streptococcus gordonii, and Streptococcus oralis are frequently isolated from these lesions (35). Virulence factors such as exopolysaccharide (26), fibronectin binding protein (24), and platelet aggregation association protein (9, 17) have been implicated in the initial fibrin colonization on damaged cardiac valves. However, oral streptococci without these properties are also isolated from the endocarditis lesions.Monocytes are prominent in early endocarditis lesions, and the number of monocytes correlates with infectivity and higher tissue factor activity in vegetations (3, 6). However, the actual role of the monocytes in the initiation and perpetuation of the vegetation remains controversial. The work of Durack and Beeson indicates that the majority of S. sanguis strains in the vegetations are phagocytosed, transported in the blood, and deposited on the vegetations in adherent monocytes (13). The monocyte population then disappears, and viable bacteria persist in the vegetations....

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Section: Discussionmentioning

confidence: 99%

Endocarditis-Associated Oral Streptococci Promote Rapid Differentiation of Monocytes into Mature Dendritic Cells

2005

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“…Although most members of lactobacilli and bifidobacteria are safe for consumption, some species such as L. rhamnosus , L. casei , L. paracasei , L. leichmannii , L. confuses and L. plantarum have been isolated from infectious sites. Lactobacilli are generally known as the normal microflora in the gastrointestinal tract; however, cases such as septicaemia, bacteremia [94–96] and endocarditis [97] have been recorded, inflicting infants, elderly and the immune-compromised [98]. These cases are uncommon and many studies have proven that probiotics were not the contributory mediator and these cases were usually prompted by individual underlying diseases.…”

Section: Safety Of Probiotics and Prebioticsmentioning

confidence: 99%

Cholesterol-Lowering Effects of Probiotics and Prebiotics: A Review of in Vivo and in Vitro Findings

Ooi

Liong

2010

IJMS

586

325

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Probiotics are live microorganisms that promote health benefits upon consumption, while prebiotics are nondigestible food ingredients that selectively stimulate the growth of beneficial microorganisms in the gastrointestinal tract. Probiotics and/or prebiotics could be used as alternative supplements to exert health benefits, including cholesterol-lowering effects on humans. Past in vivo studies showed that the administration of probiotics and/or prebiotics are effective in improving lipid profiles, including the reduction of serum/plasma total cholesterol, LDL-cholesterol and triglycerides or increment of HDL-cholesterol. However, other past studies have also shown that probiotics and prebiotics had insignificant effects on lipid profiles, disputing the hypocholesterolemic claim. Additionally, little information is available on the effective dosage of probiotics and prebiotics needed to exert hypocholesterolemic effects. Probiotics and prebiotics have been suggested to reduce cholesterol via various mechanisms. However, more clinical evidence is needed to strengthen these proposals. Safety issues regarding probiotics and/or prebiotics have also been raised despite their long history of safe use. Although probiotic-mediated infections are rare, several cases of systemic infections caused by probiotics have been reported and the issue of antibiotic resistance has sparked much debate. Prebiotics, classified as food ingredients, are generally considered safe, but overconsumption could cause intestinal discomfort. Conscientious prescription of probiotics and/or prebiotics is crucial, especially when administering to specific high risk groups such as infants, the elderly and the immuno-compromised.

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“…Strains of lactobacilli have been identified in some clinical reports as causal agents of dental caries, urinary tract infections, chorioamnionitis, endometritis, meningitis, and intra‐abdominal, liver, and spleen abscesses 38 . Commonly, these infections can be correlated with previous illnesses such as recent surgery, organ transplant, valvulopathy, diabetes mellitus, AIDS, and cancer with either immunosuppressive therapy or antibiotic treatment, which could promote the development or the selection of the microorganism 39 …”

Section: Effects Of Probiotic Translocation In Immunocompromised Indimentioning

confidence: 99%

Safety of probiotics: translocation and infection

2008

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The long history of safety has contributed to the acceptance of probiotics as a safe food adjunct. Consequently, many probiotic products and their applications have been granted GRAS (generally regarded as safe) status. However, this classification has been frequently generalized for all probiotic strains regardless of their application. Cases of probiotics from the genera Lactobacillus, Leuconostoc, Pediococcus, Enterococcus, and Bifidobacterium have been isolated from infection sites, leading to the postulation that these probiotics can translocate. Probiotic translocation is difficult to induce in healthy humans, and even if it does occur, detrimental effects are rare. Despite this, various reports have documented health-damaging effects of probiotic translocation in immunocompromised patients. Due to probiotics' high degree of safety and their morphological confusion with other pathogenic bacteria, they are often overlooked as contaminants and are least suspected as pathogens. However, the antibiotic resistance of some strains has increased the complexity of their eradication. Probiotic translocation and infection deserve further investigation and should become a facet of safety assessment so the negative effects of probiotics do not outweigh the benefits.

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Case of aortic endocarditis caused by Lactobacillus casei

Cited by 28 publications

References 20 publications

Endocarditis-Associated Oral Streptococci Promote Rapid Differentiation of Monocytes into Mature Dendritic Cells

Endocarditis-Associated Oral Streptococci Promote Rapid Differentiation of Monocytes into Mature Dendritic Cells

Cholesterol-Lowering Effects of Probiotics and Prebiotics: A Review of in Vivo and in Vitro Findings

Safety of probiotics: translocation and infection

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