Use of Robotized DNA Isolation and Real-Time PCR To Quantify and Identify Close Correlation between Levels of
            <i>Neisseria meningitidis</i>
            DNA and Lipopolysaccharides in Plasma and Cerebrospinal Fluid from Patients with Systemic Meningococcal Disease

Øvstebø, Reidun; Brandtzæg, Petter; Brusletto, Berit; Haug, Kari Bente Foss; Lande, Knut; Høiby, E. Arne; Kierulf, Peter

doi:10.1128/jcm.43.1.532.2005

Cited by 40 publications

(84 citation statements)

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“…However, this concentration is similar to lethal and sublethal doses of Staphylococci used in primate models of sepsis (30,31). During sepsis, bacteria often demonstrate massive growth within the first 12-24 h after entering the blood stream (32). The natural bactericidal activity of blood then subsequently reduces the viability of organisms that can be recovered from blood cultures (33).…”

Section: S Epidermidismentioning

confidence: 99%

“…Quantitative neonatal blood cultures often reveal CoNS concentration around 10 3 CFU/mL. However, sepsis studies assessing total bacterial DNA load have shown that the difference between dead and live bacteria may be three to four orders of magnitude, and that both dead and live bacteria induce the innate immune system (32,34). We assessed the inflammatory response during a short 3-h period and, thus, argue that the bacterial concentration used in our experiments was adequate.…”

Section: S Epidermidismentioning

confidence: 99%

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Arginine Catabolic Mobile Element Is Associated With Low Antibiotic Resistance and Low Pathogenicity in Staphylococcus epidermidis From Neonates

et al. 2010

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ABSTRACT:The arginine catabolic mobile element (ACME) in Staphylococci encodes several putative virulence factors. ACME appears to have been transferred from Staphylococcus epidermidis into Staphylococcus aureus and is strongly associated with the epidemic and virulent S. aureus USA300. We sought to determine the distribution of ACME in 128 S. epidermidis blood culture isolates from neonates and to assess ACME's impact on antibiotic resistance, biofilm production, invasive capacity, and host inflammatory response. ACME was detected in 15/64 (23%) invasive blood culture isolates and 26/64 (40%) blood culture contaminants (p ϭ 0.02). ACME-positive S. epidermidis isolates displayed less antibiotic resistance (p Ͻ 0.001) and were collected from more mature neonates (p ϭ 0.001). Biofilm production was more prevalent among ACMEnegative isolates (61/87) compared with ACME positive (18/41; p ϭ 0.004). Among the 64 children considered having an invasive infection, ACME did not influence the maximum C-reactive protein level. In an in vitro whole-blood sepsis model, there were no differences in the inflammatory response between ACME-positive and ACMEnegative isolates. We conclude that ACME in S. epidermidis from neonates was associated with less antibiotic resistance and also does not seem to be associated with increased pathogenicity. (Pediatr Res 68: 237-241, 2010) S taphylococcus epidermidis is a frequent cause of late onset sepsis in preterm neonates (1,2). The major virulence factor of S. epidermidis is biofilm formation on polymer surfaces, i.e. indwelling central venous lines (3). A wide range of other putative virulence factors, e.g. surface proteins (4), phenol soluble modulins (PSM), and poly-␥-glutamic acid (3,5-7), have also been identified. However, their clinical relevance is yet to be proven.The arginine catabolic mobile element (ACME) is a genomic island in Staphylococci that may contribute to enhanced pathogenicity. It was first discovered in the community associated methicillin-resistant Staphylococcus aureus (CA-MRSA) USA300 strain and the biofilm-negative S. epidermidis strain ATCC12228 (8). ACME contains two characteristic gene clusters (the arc-operon and the opp3-operon) that are homologs of virulence determinants in other bacterial species. The arc-operon, a characteristic cluster of six genes, encodes several enzymes in the arginine deiminase catabolic pathway, a putative virulence pathway that convert L-arginine to carbon dioxide, carbamoyl ornithine, ammonia, and ATP (9,10). The opp3-operon encodes an oligopeptide permease system. Similar opp-operons in other bacterial species have a wide array of functions including pheromone transport, chemotaxis, and expression of virulence determinants (8). ACME has been divided into three allotypes (8 -11). ACME-I, first found in S. aureus USA300, possess the arc-operon and the opp3-operon. ACME-II, first found in S. epidermidis ATCC12228, consists mainly of the arc-operon. ACME-III has only the opp3-operon and lacks the arc-operon. All three allotypes have ...

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Section: S Epidermidismentioning

confidence: 99%

Section: S Epidermidismentioning

confidence: 99%

Arginine Catabolic Mobile Element Is Associated With Low Antibiotic Resistance and Low Pathogenicity in Staphylococcus epidermidis From Neonates

et al. 2010

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“…Some authors have studied the association between bacterial DNA load and disease severity in patients with invasive bacterial disease (16)(17)(18)(19). However, to date, these techniques have not been evaluated as a prognostic tool for complications other than mortality in patients previously diagnosed with BSI.…”

Section: Discussionmentioning

confidence: 99%

“…These researchers also found, as did we, that DNA remains detectable in BC-negative samples. Other researchers previously found that bacterial DNA load, although derived from nonviable bacteria, can be a clinically useful marker for the prediction of severity of meningococcal and pneumococcal disease (17)(18)(19).…”

Section: Discussionmentioning

confidence: 99%

The Value of Combining Blood Culture and SeptiFast Data for Predicting Complicated Bloodstream Infections Caused by Gram-Positive Bacteria or Candida Species

et al. 2013

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Management of complicated bloodstream infections requires more aggressive treatment than uncomplicated bloodstream infections.We assessed the value of follow-up blood culture in bloodstream infections caused by Staphylococcus aureus, Enterococcus spp., Streptococcus spp., and Candida spp. and studied the value of persistence of DNA in blood (using SeptiFast) for predicting complicated bloodstream infections. Patients with bloodstream infections caused by these microorganisms were enrolled prospectively. After the first positive blood culture, samples were obtained every third day to perform blood culture and SeptiFast analyses simultaneously. Patients were followed to detect complicated bloodstream infection. The study sample comprised 119 patients. One-third of the patients developed complicated bloodstream infections. The values of persistently positive tests to predict complicated bloodstream infections were as follows: SeptiFast positive samples (sensitivity, 56%; specificity, 79.5%; positive predictive value, 54%; negative predictive value, 80.5%; accuracy, 72.3%) and positive blood cultures (sensitivity, 30.5%; specificity, 92.8%; positive predictive value, 64%; negative predictive value, 75.5%; accuracy, 73.9%). Multivariate analysis showed that patients with a positive SeptiFast result between days 3 and 7 had an almost 8-fold-higher risk of developing a complicated bloodstream infection. In S. aureus, the combination of both techniques to exclude endovascular complications was significantly better than the use of blood culture alone. We obtained a score with variables selected by the multivariate model.

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“…The innate immune response to microbial DNA could be one of the connections between infectious agents and diseases such as chronic inflammatory intestinal diseases (4) or systemic lupus erythematosus (5)(6)(7). Furthermore, bacterial DNA could be playing a key role in severe conditions like Gram-negative septic shock (8), in which a dysregulated innate immune response mediated by TLRs has been confirmed (9 -11). Immunostimulatory effects of bacterial DNA on mammalian cells are exerted via the intracellular TLR9 (12).…”

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confidence: 99%

Cutting Edge: Natural DNA Repetitive Extragenic Sequences from Gram-Negative Pathogens Strongly Stimulate TLR9

Magnusson

Tobes

Sancho

et al. 2007

The Journal of Immunology

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Clinical and epidemiologic studies have suggested a connection between infectious agents and autoimmune diseases (1-3). The innate immune response to microbial DNA could be one of the connections between infectious agents and diseases such as chronic inflammatory intestinal diseases (4) or systemic lupus erythematosus (5-7). Furthermore, bacterial DNA could be playing a key role in severe conditions like Gram-negative septic shock (8), in which a dysregulated innate immune response mediated by TLRs has been confirmed (9 -11). Immunostimulatory effects of bacterial DNA on mammalian cells are exerted via the intracellular TLR9 (12). TLR9 distinguishes bacterial DNA from self-DNA detecting special patterns in DNA fragments (12). Studies with oligodeoxynucleotides (ODNs) have allowed the determination of features favoring the immunostimulatory ability of DNA sequences (13): DNA fragments with lengths of ϳ25 nt; the presence of unmethylated CpG motifs following the pattern "not C, C, G, not G" separated by AT-rich stretches of ϳ2-4 nt; and palindromicity.These features have been determined analyzing the immunostimulatory potential of synthetic ODNs, but which kinds of natural bacterial sequences have immunostimulatory potential is unknown. This could be critical to the understanding of how bacteria activate immune responses.In this study, we searched for bacterial DNA sequence candidates as natural TLR9 ligands. Our results prove that bacterial repetitive extragenic palindromic (REPs) sequences are natural TLR9 ligands that allow the innate immune system to distinguish bacterial DNA. Materials and Methods Bioinformatics analysisTo detect REP sequences we used a BLAST-based strategy specially designed to detect repetitive extragenic and palindromic sequences. We developed Cϩϩ programs to assist in the analysis of REPs in the entire genomes. The genomes analyzed were: Escherichia coli K12 (GenBank U00096.2; RefSeq NC_000913.2), Salmonella enterica subsp. enterica serovar typhi (GenBank AL513382.1; RefSeq NC_003198.1), Pseudomonas aeruginosa (PAO1 GenBank AE004091.2; RefSeq NC_002516.2), and Neisseria meningitidis serogroup B strain MC58 (GenBankAE002098.2; RefSeq NC_003112.2). For multiple alignment of the identified REPs in each genome, we used the program Multalign (14) available at http://prodes.toulouse.inra.fr/ multalin/multalin.html.REPs to be experimentally tested were selected based on the fulfillment of the consensus REPs of every species, on the abundance of identical or very similar copies in the genome and on the presence of CpG motifs. AnimalsTLR9 knockout mice (B6.129P2-Tlr9 tm1Aki ) were a gift from S. Akira (Re-

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Use of Robotized DNA Isolation and Real-Time PCR To Quantify and Identify Close Correlation between Levels of Neisseria meningitidis DNA and Lipopolysaccharides in Plasma and Cerebrospinal Fluid from Patients with Systemic Meningococcal Disease

Cited by 40 publications

References 0 publications

Arginine Catabolic Mobile Element Is Associated With Low Antibiotic Resistance and Low Pathogenicity in Staphylococcus epidermidis From Neonates

Arginine Catabolic Mobile Element Is Associated With Low Antibiotic Resistance and Low Pathogenicity in Staphylococcus epidermidis From Neonates

The Value of Combining Blood Culture and SeptiFast Data for Predicting Complicated Bloodstream Infections Caused by Gram-Positive Bacteria or Candida Species

Cutting Edge: Natural DNA Repetitive Extragenic Sequences from Gram-Negative Pathogens Strongly Stimulate TLR9

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