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F Vandenesch

Publications and source records attributed to F Vandenesch.

At least 73 records · Page 4Linked to original sources
PubMed1997

Toxin involvement in staphylococcal scalded skin syndrome.

The production of staphylococcal exfoliative toxin A (ETA) and toxin B (ETB), toxic shock syndrome toxin (TSST-1), and enterotoxins A-E was analyzed in 60 Staphylococcus aureus strains isolated from children with scalded skin syndrome (15 with generalized exfoliative syndrome, 28 with bullous impetigo, and 17 with staphylococcal scarlet fever). All strains isolated from patients with generalized exfoliative syndrome or bullous impetigo produced ETA and/or ETB and caused a Nikolsky's sign when injected subcutaneously into newborn mice. In contrast, exfoliative toxin was detected in an S. aureus strain from only one of 17 case of staphylococcal scarlet fever; the 16 other S. aureus strains produced TSST-1 and/or an enterotoxin. In conclusion, enterotoxins or TSST-1 are more frequently associated with staphylococcal scarlet fever than are exfoliative toxins. Hence staphylococcal scarlet fever may well represent an abortive form of toxic shock syndrome rather than a milder form of staphylococcal scalded skin syndrome.

Animals↗
PubMed1997

Synergistic hemolytic activity of Staphylococcus lugdunensis is mediated by three peptides encoded by a non-agr genetic locus.

Some strains of the coagulase-negative Staphylococcus lugdunensis produce a synergistic hemolytic activity (SLUSH), phenotypically similar to the delta-hemolysin of S. aureus. Reverse-phase high-pressure liquid chromatography of supernatants from S. lugdunensis 307 yielded three late-eluting peaks of 3.5 kDa with synergistic hemolytic activity. A degenerate oligonucleotide probe was designed from partial amino acid sequences of the 23-amino-acid (aa) tryptic fragments from one of the three peaks and hybridized to a single 2.8-kb HindIII chromosomal fragment. The relevant portion of this fragment was cloned by PCR, and sequencing showed the presence of three related open reading frames (ORFs), SLUSH-A, SLUSH-B, and SLUSH-C, preceded by an unrelated short potentially coding sequence (ORF-X), cotranscribed on a polycistronic 838-nucleotide mRNA. The amino acid sequences of the peptides from the three peaks align perfectly with the predicted sequences from the three SLUSH ORFs (peak I = SLUSH-B; peak II = SLUSH-C; peak III = SLUSH-A). These three peptides are closely related (amino acid homology, >76%) and do not show significant homology to S. aureus delta-hemolysin but do resemble a Salmonella typhimurium invasin and the "gonococcal growth inhibitor," a bacteriocin secreted by Staphylococcus haemolyticus. The predicted ORF-X gene product is a 24-aa peptide with no homology to the SLUSH peptides.

Amino Acid Sequence↗
PubMed1997

Comparative performances of six agglutination kits assessed by using typical and atypical strains of Staphylococcus aureus.

Six commercial agglutination tests designed for the identification of Staphylococcus aureus were compared by using a strain collection which included 512 staphylococci representing 33 species (318 isolates of Staphylococcus aureus [including 144 oxacillin resistant], 46 S. epidermidis isolates, 15 S. haemolyticus isolates, 12 S. saprophyticus isolates, 29 S. schleiferi isolates, 30 S. lugdunensis isolates, and 62 other coagulase-negative staphylococci). This group also included a proportion of strains with unusual phenotypes (e.g., 19 coagulase-negative S. aureus isolates, 26 clumping factor-negative S. aureus isolates, and 4 S. aureus isolates each with a double deficiency). The overall sensitivity for identification of typical and atypical S. aureus was high with the Staphaurex Plus test (Murex Biotech) (99.7%), the Pastorex Staph Plus test (Sanofi Diagnostics Pasteur) (99.7%), and the Slidex Staph Plus test (bioMérieux) (100%). The overall rate of specificity was affected by the unusual inclusion in this study of a high proportion of non-S. aureus species, such as S. lugdunensis and S. schleiferi, which express a clumping factor and therefore produce a positive result with the agglutination tests.

Agglutination Tests↗
PubMed1997

The first clinical isolate of Legionella parisiensis, from a liver transplant patient with pneumonia.

A bluish white autofluorescent strain of Legionella was isolated from the tracheal aspirate of a female liver transplant patient who developed hospital-acquired pneumonia. This strain had biochemical characteristics compatible with those of L. cherrii, L. anisa, and L. parisiensis and could not be differentiated from L. bozemanii and L. parisiensis by the direct fluorescent-antibody assay. Phylogenetic analysis of partial 16S rRNA gene sequences of this strain (ATCC 700174) revealed the closest homology to the species L. parisiensis (99.5%). An L. parisiensis species-specific profile was also identified by a random amplified polymorphic DNA technique. This is the first report of L. parisiensis isolation from humans.

Adult↗
PubMed1996

New serotype of Bartonella henselae in endocarditis and cat-scratch disease.

BACKGROUND: The fastidious nature of Bartonella henselae is such that demonstration of clinical infection relies mainly on serological or molecular biological methods. Only five isolates have been obtained from patients with cat-scratch disease (CSD) and none from endocarditis. METHODS: We isolated B henselae from a CSD patient and, for the first time, from a patient with endocarditis. The isolates were characterised on the basis of morphology, biochemistry, cell-wall fatty-acid analysis, PCR-restriction fragment length polymorphism analysis of the 16-23S intragenic spacer region, and 16S rRNA gene sequences. Characterisation of these isolates indicated them to belong to a new serogroup, which we have called "Marseille", and to a new genotype based on the 16S rRNA gene sequence. The new variant was incorporated into an immuno-fluorescence antibody test (IFAT), which was used to reassess serum samples from 113 CSD patients who were seronegative with the conventional IFAT. FINDINGS: 18 (16%) of these apparently seronegative patients yielded significantly raised titres. 20 CSD patients who were seropositive as judged by the conventional IFAT remained seropositive with the new IFAT. INTERPRETATION: Antigenic variability within the species is one possible reason for inconsistent results in the serological diagnosis of CSD.

Adult↗
PubMed1996

Nucleic acid sequence and affiliation of pLUG10, a novel cadmium resistance plasmid from Staphylococcus lugdunensis.

Tolerance of Staphylococcus lugdunensis to relatively high levels of cadmium is mediated by a 3117-bp plasmid, pLUG10. Sequencing reveals three major open reading frames (ORFs) in a single orientation. One ORF encompasses the origin of replication and its predicted product (RepL: 350 amino acids (aa)) shows 70% homology in its deduced aa sequence with Rep proteins of the pT181 family. A lagging strand conversion signal (palA) very similar to that of class 1 plasmids is present outside the rep-ori locus. The other two ORFs of 209 and 116 aa show 92.5% homology between their deduced aa sequences and the CadB and CadX peptides from the pOX6 plasmid of Staphylococcus aureus. The CadX-like peptide is 40% homologous to the S. aureus CadC product. Deletion of the C-terminal cadX gene by restriction enzyme digestion or frame-shift inactivation of the cadB gene reduced, but did not completely abolish, cadmium resistance. The two gene products may act cooperatively to confer cadmium resistance in S. lugdunensis.

Amino Acid Sequence↗
PubMed1996

Distribution of mip-related sequences in 39 species (48 serogroups) of Legionellaceae.

The macrophage infectivity potentiator gene (mip) from Legionella pneumophila is a major virulence factor of the species. Thus, mip-detection by amplification has been proposed to assess the presence of L. pneumophila in clinical and environmental samples. The distribution of mip-related sequences within the Legionellaceae was studied by DNA amplification using mip-specific primers followed by Southern blot hybridization with an internal probe. Thirty-nine species (48 serogroups) of Legionellaceae were screened in this attempt. Using this approach, sequences related to mip were observed in 89% of the tested species including the most recently described L. fairfieldensis, L. lansingensis and L. shakespearei. In several cases, cloning and sequencing of the amplified products confirmed the high levels of similarity between the sequence found in non-pneumophila species with that of the L. pneumophila mip gene. This confirms previous reports that mip related genes are widespread among Legionellaceae and therefore specific detection of the species L. pneumophila cannot be based on mip-targeted amplification.

Blotting, Southern↗
PubMed1996

Coagulase-negative staphylococci isolated from two cases of toxic shock syndrome lack superantigenic activity, but induce cytokine production.

Two strains of Staphylococcus epidermidis isolated from patients with toxic shock symptoms have been reported to carry genes related to S. aureus enterotoxins B and C by dot-blot hybridisation, although the corresponding superantigenic toxins were not detected immunologically. We here show that these strains produce no superantigens capable of stimulating proliferation of human mononuclear leukocytes or rabbit splenocytes, and that no DNA homologous to the seb or sec genes can be detected by PCR. However, stimulation of human monocytes by whole killed bacteria induced dose-dependent production of the cytokines TNF alpha, IL-1 beta and IL-6, which may be responsible for the clinical symptoms in these patients.

Antigens, Bacterial↗
PubMed1995

The agr P2 operon: an autocatalytic sensory transduction system in Staphylococcus aureus.

The synthesis of virulence factors and other exoproteins in Staphylococcus aureus is controlled by the global regulator, agr. Expression of secreted proteins is up-regulated in the postexponential growth phase, whereas expression of surface proteins is down-regulated by agr. The agr locus consists of two divergent operons, transcribed from neighboring but non-overlapping promoters, P2 and P3. The P2 operon sequence, reported here, contains 4 open reading frames, agrA, C, D, and B, of which A and C appear to encode proteins of a classical 2-component signal transduction pathway. The P3 operon specifies a 0.5 kb transcript, RNA III, which is the actual effector of the agr response, and, incidentally, encodes the agr-regulated peptide delta-hemolysin. Transcriptional fusions have shown that both P2 and P3 are agr sensitive (function in an agr+ but not in an agr- background) and deletion analysis has shown that all four of the P2 ORFs are involved; agrA and agrC seem to be absolutely required for the transcriptional activation of the agr locus, whereas agrB and agrD seem to be partially required. Since transcription of P2 requires P2 operon products, the P2 operon is autocatalytic, and is thus admirably suited to the need for rapid production of exoproteins at a time when overall growth is coming to a halt.

Amino Acid Sequence↗
PubMed1995

Bartonella (Rochalimaea) quintana endocarditis in three homeless men.

BACKGROUND: Bartonella (Rochalimaea) quintana is the agent of trench fever and is transmitted by the body louse. We searched for this organism in three alcoholic homeless men with endocarditis. METHODS: Blood samples were cultured on a human endothelial cell line and on blood agar. Bacteria were identified by sequencing the amplified 16S ribosomal RNA gene. The presence of bartonella in tissue was assessed by Gram's staining, immunostaining, and polymerase-chain-reaction amplification. Serologic studies for antibodies to bartonella species were performed by indirect immunofluorescence and Western immunoblotting. RESULTS: B. quintana was isolated from one patient in the blood-agar culture and from the other two patients in the endothelial-cell culture. The organism was also identified by both immunostaining and molecular techniques in the valvular vegetations from the three patients and in a cervical lymph node from one patient. The 16S ribosomal RNA gene sequences of the three isolates were almost identical to that of the prototype strain of B. quintana. High titers of antibodies to B. quintana were detected in all three patients, but so were cross-reacting antibodies to chlamydia species. In all three patients studies were repeatedly negative for antibodies to the human immunodeficiency virus. CONCLUSIONS: B. quintana is a cause of endocarditis in homeless patients and may be serologically misdiagnosed as a chlamydial infection.

Adult↗
PubMed1995

[Aseptic meningitis. Demonstration of bacterial DNA in cerebrospinal fluid by gene amplification].

OBJECTIVE: To develop a diagnostic tool to recognize whether a postoperative meningitis occurring in neurosurgical patients is of bacteriological origin or not, in detecting in CSF bacterial DNA with the polymerase chain reaction (PCR) technique. STUDY DESIGN: Laboratory study. PATIENTS: Twenty-seven neurosurgical ICU patients associating, in the postoperative period, the CDC criteria of meningitis and a neutrophil polymorphonuclear count over 100 cells.mm-3 were allocated either into the MB+ group (n = 7) when their CSF culture was positive or in the MB- group (n = 20) when the culture was sterile. The CSF of 43 neurosurgical ICU patients without postoperative clinical and biological features of meningitis acted as controls. Sixteen specimens out of the 43 were inoculated with bacteria at a known concentration. METHODS: The CSF specimens of all patients were tested for the presence of eurcaryote DNA using the PCR technique. Beforehand its sensitivity had been assessed using the inoculated CSF of control group: a positive amplification at 20 cycles was equivalent to 10(5) CFU.mL-1 and a positive amplification at 25 cycles to 10(3) CFU.mL-1. RESULTS: In the 43 sterile control CSF specimens the amplification was negative in all at 20 cycles and in 42 at 25 cycles. In the 16 previously sterile control specimens supplemented with bacteria, as well as in the CSF of all 7 patients of MB+ group the amplification was positive at 20 and 25 cycles. In those of MB- group the amplification was negative in all at 20 cycles, but was positive in 19 out of 20 at 25 cycles. Southern blot with specific procaryote probes was positive with amplification products from CSF of MB+ and MB- groups and negative with control CSFs and human DNA. DISCUSSION: The presence of bacteria in CSF of patients sustaining a meningitis can be accurately detected through their DNA. Postoperative aseptic meningitides may have a bacterial origin. PCR can be used as a routine technique to provide a diagnosis of bacterial meningitis in less than 6 hours. Additionally specific oligonucleotides allow to identify the bacteria in less than 12 hours.

Adolescent↗
PubMed1995

Identification and ribotypes of Staphylococcus caprae isolates isolated as human pathogens and from goat milk.

We report five cases of human infection with Staphylococcus caprae. Two were community acquired (one case each of endocarditis and urinary tract infection); the other three were acquired in a hospital (two cases of bacteremia associated with intravenous access and one case of urinary tract infection). Analysis of human isolates and goat isolates from eight herds showed that they could be misidentified by some commercial identification systems but were clearly identified as S. caprae by ribotyping, according to their species-specific ribotype. Phylogenetic methods applied to the ribotypes did not reveal two distinct lineages corresponding to the goat and human origins of the isolates, although human ribotypes were clearly distinguishable by the presence of a core of four specific bands. The latter observation may reflect some degree of evolutionary change within the species between human and goat isolates.

Adult↗
PubMed1995

Catheter-related bacteremia associated with coagulase-positive Staphylococcus intermedius.

We report a case of catheter-related bacteremia in a 63-year-old patient caused by Staphylococcus intermedius. Clinical resolution of the infection was obtained after removal of the intravenous device and antibiotic treatment. This observation emphasizes the risk of confusion between S. intermedius and Staphylococcus aureus if only a coagulase test is done.

Bacteremia↗
PubMed1994

Coagulase deficiency in clinical isolates of Staphylococcus aureus involves both transcriptional and post-transcriptional defects.

The molecular basis of the non-expression of coagulase was investigated for 14 coagulase-negative isolates of Staphylococcus aureus obtained from different clinical samples. These isolates had typical S. aureus characteristics such as production of clumping factor, DNAase and protein A, but, with one exception, failed to produce detectable amounts of alpha-haemolysin. All 14 strains had DNA homologous to the coagulase gene (coa), but a coa-specific transcript was found in only seven of them. alpha-Haemolysin mRNA was detected in only eight strains without direct correlation to coa-mRNA expression. Thus, coagulase and alpha-haemolysin deficiencies in S. aureus may involve either transcriptional or post-transcriptional alterations although additional regulatory factors may influence the expression of both genes.

Bacterial Toxins↗
PubMed1994

Glycerol monolaurate inhibits the production of beta-lactamase, toxic shock toxin-1, and other staphylococcal exoproteins by interfering with signal transduction.

Glycerol monolaurate (GML) is a naturally occurring surfactant that is used widely as an emulsifier in the food and cosmetics industries and is generally regarded as lacking in important biological activities. The recent observation that it inhibits the production of staphylococcal toxic shock toxin-1 (P. M. Schlievert, J. R. Deringer, M. H. Kim, S. J. Projan, and R. P. Novick, Antimicrob. Agents Chemother. 36:626-631, 1992) is therefore rather surprising and raises the interesting question of how such a compound might interact with cells. In this report, we show that GML inhibits the synthesis of most staphylococcal toxins and other exoproteins and that it does so at the level of transcription. We find that GML blocks the induction but not the constitutive synthesis of beta-lactamase, suggesting that it acts by interfering with signal transduction.

Bacterial Proteins↗