Early Microascus cinereus endocarditis of a prosthetic valve implanted after Staphylococcus aureus endocarditis of the native valve.
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Adult↗
Biomedical subjects
F Vandenesch
Publications and source records attributed to F Vandenesch.
Legionella taurinensis sp. nov., a new species antigenically similar to Legionella spiritensis.
A group of 42 Legionella-like organisms reacting specifically with Legionella spiritensis serogroup 1 antisera were collected throughout Europe by the Centre National de Référence (French National Reference Centre) for Legionella. This group of isolates differed somewhat from L. spiritensis in terms of biochemical reactions, ubiquinone content and protein profile. The latter two analyses revealed that one of these L. spiritensis-like isolates, Turin I no. 1T, was highly related, but not identical to any of the red autofluorescent species of Legionella. In fact, this strain was the first of these particular isolates recognized to emit a red autofluorescence when exposed to UV light. Profile analysis of randomly amplified polymorphic DNA established that the red autofluorescent L. spiritensis-like isolates constituted a homogeneous group distinct from Legionella rubrilucens and Legionella erythra. DNA-DNA hybridization studies involving the use of S1 nuclease confirmed that the indicated group of isolates are a new species of Legionella, for which the name Legionella taurinensis is proposed with strain Turin I no. 1T (deposited as ATCC 700508T) as the type strain.
Antigens, Bacterial↗
Distribution of genes encoding resistance to macrolides, lincosamides, and streptogramins among staphylococci.
The relative frequency of 10 determinants of resistance to macrolides, lincosamides, and streptogramins was investigated by PCR in a series of 294 macrolide-, lincosamide-, and/or streptogramin-resistant clinical isolates of Staphylococcus aureus and coagulase-negative staphylococci isolated in 1995 from 32 French hospitals. Resistance was mainly due to the presence of ermA or ermC genes, which were detected in 259 strains (88%), in particular those resistant to methicillin (78% of the strains). Macrolide resistance due to msrA was more prevalent in coagulase-negative staphylococci (14.6%) than in S. aureus (2.1%). Genes related to linA/linA' and conferring resistance to lincomycin were detected in one strain of S. aureus and seven strains of coagulase-negative staphylococci. Resistance to pristinamycin and quinupristin-dalfopristin was phenotypically detected in 10 strains of S. aureus and in three strains of coagulase-negative staphylococci; it was always associated with resistance to type A streptogramins encoded by vat or vatB genes and occurred in association with erm genes. The vga gene conferring decreased susceptibility to type A streptogramins was present alone in three strains of coagulase-negative staphylococci and in combination with erm genes in 10 strains of coagulase-negative staphylococci. A combination of vga-vgb-vat and ermA genes was found in a single strain of S. epidermidis.
Anti-Bacterial Agents↗
Emergence and spread in French hospitals of methicillin-resistant Staphylococcus aureus with increasing susceptibility to gentamicin and other antibiotics.
Oxacillin (methicillin) resistance in methicillin-resistant Staphylococcus aureus (MRSA) is associated with an increased incidence of resistance to other antibiotics, which has increased since it was first reported in 1969. In 1992 a new phenotype of MRSA arose in France; this was characterized by a heterogeneous expression of resistance to oxacillin and susceptibility to various antibiotics, including gentamicin but also tetracycline, minocycline, lincomycin, pristinamycin, co-trimoxazole, rifampin, and fusidic acid. In French hospitals a longitudinal nationwide surveillance of antibiotic resistance in S. aureus has allowed for the detection of changes in antibiotic susceptibility profiles. Seven French clinical laboratories (six from the mainland and one from the West Indies) reported the results of susceptibility testing of 57,347 S. aureus strains isolated in their institutes between 1992 and 1998. Over a 7-year period the incidence of isolation of gentamicin-susceptible MRSA (GS-MRSA) strains has steadily increased to represent, in 1998, 46.8 to 94.4% of the MRSA strains, irrespective of the overall incidence of MRSA. Two predominant types recognized by pulsed-field gel electrophoresis (PFGE) accounted for the majority of the GS-MRSA in different mainland hospitals, both differing from the predominant type observed in the French West Indies. Some GS-MRSA and gentamicin-resistant MRSA (GR-MRSA) strains had closely related PFGE profiles, and hybridization studies confirmed the lack in GS-MRSA of the aac6'-aph2" gene, which confers resistance to all aminoglycosides, with conservation of the ant4' gene, which confers resistance to kanamycin, tobramycin, and amikacin. Thus, it is likely that certain GS-MRSA strains could have emerged from GR-MRSA strains by excision or deletion of the aac6'-aph2" gene.
Cross Infection↗
Involvement of enterotoxins G and I in staphylococcal toxic shock syndrome and staphylococcal scarlet fever.
We investigated the involvement of the recently described staphylococcal enterotoxins G and I in toxic shock syndrome. We reexamined Staphylococcus aureus strains isolated from patients with menstrual and nonmenstrual toxic shock syndrome (nine cases) or staphylococcal scarlet fever (three cases). These strains were selected because they produced none of the toxins known to be involved in these syndromes (toxic shock syndrome toxin 1 and enterotoxins A, B, C, and D), enterotoxin E or H, or exfoliative toxin A or B, despite the fact that superantigenic toxins were detected in a CD69-specific flow cytometry assay measuring T-cell activation. Sets of primers specific to the enterotoxin G and I genes (seg and sei, respectively) were designed and used for PCR amplification. All of the strains were positive for seg and sei. Sequence analysis confirmed that the PCR products, corresponded to the target genes. We suggest that staphylococcal enterotoxins G and I may be capable of causing human staphylococcal toxic shock syndrome and staphylococcal scarlet fever.
Enterotoxins↗
Role of the preaxillary flora in pacemaker infections: a prospective study.
BACKGROUND: Infection remains a severe complication after pacemaker implantation. The purpose of our prospective study was to evaluate the role of the local bacteriologic flora in its occurrence. METHODS AND RESULTS: Specimens were collected at the site of implantation for culture from the skin and the pocket before and after insertion in a consecutive series of patients who underwent elective permanent pacemaker implantation. Microorganisms isolated both at the time of insertion and of any potentially infective complication were compared by using conventional speciation and ribotyping. There were 103 patients (67 men and 36 women) whose age ranged from 16 to 93 years (mean+/-SD, 67+/-15). At the time of pacemaker implantation, a total of 267 isolates were identified. The majority (85%) were staphylococci. During a mean follow-up of 16.5 months (range, 1 to 24), infection occurred in four patients (3.9%). In two of them, an isolate of Staphylococcus schleiferi was recognized by molecular method as identical to the one previously found in the pacemaker pocket. In one patient, Staphylococcus aureus, an organism that was absent at the time of pacemaker insertion, was isolated. In another patient, a Staphylococcus epidermidis was identified both at the time of pacemaker insertion and when erosion occurred; however, their antibiotic resistance profiles were different. CONCLUSIONS: This study strongly supports the hypothesis that pacemaker-related infections are mainly due to local contamination during implantation. S schleiferi appears to play an underestimated role in infectious colonization of implanted biomaterials and should be regarded as an important opportunistic pathogen.
Abscess↗
First isolation in Europe of Legionella feeleii from two cases of pneumonia.
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Adult↗
Transmembrane topology and histidine protein kinase activity of AgrC, the agr signal receptor in Staphylococcus aureus.
The agr P2 operon in Staphylococcus aureus codes for the elements of a density-sensing cassette made up of a typical two-component signalling system and its corresponding inducer. It is postulated that the autoinducer, a post-translationally modified octapeptide generated from the AgrD peptide, interacts with a receptor protein, coded by agrC, to transmit a signal via AgrA regulating expression of staphylococcal virulence genes through expression of agr RNA III. We show by analysis of PhoA fusions that AgrC is a transmembrane protein, and confirm using Western blotting that a 46 kDa protein corresponding to AgrC is present in the bacterial membrane. This protein is autophosphorylated on a histidine residue only in response to supernatants from an agr+ strain, and can also respond to the purified native octapeptide. A recombinant fusion protein where most of the N-terminal region of AgrC is replaced by the Escherichia coli maltose-binding protein is also autophosphorylated in response to stimulation by agr+ supernatants or purified octapeptide. We conclude that AgrC is the sensor molecule of a typical two-component signal system in S. aureus, and that the ligand-binding site of AgrC is probably located in the third extracellular loop of the protein.
Bacterial Proteins↗
Species identification of Legionella via intergenic 16S-23S ribosomal spacer PCR analysis.
Species identification of Legionella in routine laboratory testing is hampered by the lack of highly discriminatory phenotypic tests. Amplification polymorphism of the intergenic 16S-23S spacer regions (ISR) has been previously developed for identification of species within the Legionellaceae [Hookey, J.V., Birtles, R.J. & Saunders, N.A. (1995). J Clin Microbiol 33, 2377-2381], but it did not provide enough resolution to distinguish all members of the bluish-white autofluorescent species and the red autofluorescent group of the Legionellaceae. By choosing new primers that target regions 4 (positions 1521-1541 of Escherichia coli 16S rRNA gene) and 6 (positions 114-132 of E.coli 23S rRNA gene) within the rDNA operon close to the 16S-23S intergenic spacer, 34 profiles were determined among the 79 type and reference strains representing 42 species that were tested. Analysis of the RFLP generated after Hinfl restriction digestion of the PCR products further improved the method, allowing complete discrimination among the species and subspecies of Legionella tested. Twenty-three well-identified strains from unrelated origins belonging to seven species gave amplification patterns identical to that of their type strain. The technique was also tested on 80 field isolates that could not be unequivocally assigned to groups by phenotypic methods. Seventy-two per cent (58/80) of these isolates had a profile identical to that of a type strain, while 27% (22/80) may correspond to new taxa since their ISR-PCR profiles did not match any of the known profiles.
Base Sequence↗
trans-complementation of a Staphylococcus aureus agr mutant by Staphylococcus lugdunensis agr RNAIII.
RNAIII from Staphylococcus lugdunensis (RNAIII-sl) in a Staphylococcus aureus agr mutant partially restored the Agr phenotype. A chimeric construct consisting of the 5' end of RNAIII-sl and the 3' end of RNAIII from S. aureus restored the Agr phenotype to a greater extent, suggesting the presence of independent regulatory domains.
Bacterial Proteins↗
Comparative analysis of infrequent-restriction-site PCR and pulsed-field gel electrophoresis for epidemiological typing of Legionella pneumophila serogroup 1 strains.
Two methods were compared for the analysis of 48 unrelated and epidemiologically related Legionella pneumophila serogroup 1 isolates. These are the infrequent-restriction-site PCR (IRS-PCR) assay with adapters designed for XbaI and PstI restriction sites and the pulsed-field gel electrophoresis (PFGE) analysis determined after DNA restriction with SfiI. Both methods demonstrated a high level of discrimination with a similar capacity for differentiating 23 of the 24 unrelated isolates. PFGE analysis and IRS-PCR assay were both able to identify epidemiologically related isolates of L. pneumophila from three outbreaks. Hence, IRS-PCR assay appears to be a reproducible (intergel reproducibility, 100%) and discriminative (discriminatory index, > or = 0.996) tool for typing of Legionella. Compared to PFGE, however, IRS-PCR presented an advantage through ease of performance and with attributes of rapidity and sensitivity of target DNA.
Animals↗
Identification of Legionella species by random amplified polymorphic DNA profiles.
Random amplified polymorphic DNA (RAPD) was used for the identification of Legionella species. Primer SK2 (5'-CGGCGGCGGCGG-3') and standardized RAPD conditions gave the technique a reproducibility of 93 to 100%, depending on the species tested. Species-specific patterns corresponding to the 42 Legionella species were consequently defined by this method; the patterns were dependent on the recognition of a core of common bands for each species. This specificity was demonstrated by testing 65 type strains and 265 environmental and clinical isolates. No serogroup-specific profiles were obtained. A number of unidentified Legionella isolates potentially corresponding to new species were clustered in four groups. RAPD analysis appears to be a rapid and reproducible technique for identification of Legionella isolates to the species level without further restriction or hybridization.
Base Sequence↗
Detection of staphylococcal superantigenic toxins by a CD69-specific cytofluorimetric assay measuring T-cell activation.
The presence of staphylococcal superantigenic toxins in the supernatants of liquid cultures was detected by an easy and rapid method assessing the activation of T lymphocytes by cytofluorimetric measurement of CD69 expression. Staphylococcus aureus cells were grown in Eagle's minimum essential medium supplemented with 5% heat-inactivated fetal calf serum. Supernatant fluids from all S. aureus strains producing superantigen-related toxins, including enterotoxins A to E, toxic shock syndrome toxin, and exfoliative toxins A and B, induced CD69 expression in a significantly higher number of T cells than a cutoff of 2%. This CD69 assay might be used for initial detection of superantigens from S. aureus strains isolated in the context of staphylococcal toxemia or related chronic human diseases such as atopic dermatitis or Kawasaki syndrome.
Antigens, CD↗
Outbreak of Staphylococcus schleiferi wound infections: strain characterization by randomly amplified polymorphic DNA analysis, PCR ribotyping, conventional ribotyping, and pulsed-field gel electrophoresis.
Within a 1-year period, six surgical-site infections (SSI) caused by Staphylococcus schleiferi were observed in the department of cardiac surgery of Ignatius Hospital, Breda, The Netherlands. Since outbreaks caused by this species of coagulase-negative staphylococci have not been described before, an extensive environmental survey and a case control study were performed in combination with molecular typing of the causative microorganism in order to identify potential sources of infection. Variability, as detected by four different genotyping methods (random amplification of polymorphic DNA [RAPD], conventional and PCR-mediated ribotyping, and pulsed-field gel electrophoresis [PFGE] of DNA macro restriction fragments), appeared to be limited both among the clinical isolates and among several control strains obtained from various unrelated sources. Among unrelated strains, RAPD and PCR-mediated ribotyping identified two types only, whereas seven different types were identified in a relatively concordant manner by conventional ribotyping and PFGE. The latter two procedures proved to be the most useful tools for tracking the epidemiology of S. schleiferi. Four of the outbreak-related strains were identical by both methods, and two isolates showed limited differences. In the search for a potential source of S. schleiferi infection, two slightly different PFGE types were encountered on several occasions in the nose of a single surgeon. These strains were, however, clearly different from the outbreak type. In contrast, S. schleiferi cultures remained negative for two persons identified on the basis of case control analysis. It was demonstrated that SSI caused by S. schleiferi had a clinical impact for patients comparable to that of a wound infection caused by Staphylococcus aureus. This report describes the first well-documented outbreak of S. schleiferi infection. A source of the outbreak was not detected.
Aged↗
Distribution of the synergistic haemolysin genes hld and slush with respect to agr in human staphylococci.
Several staphylococcal species express a synergistic activity which potentiates hemolysis by beta-hemolysin. In Staphylococcus aureus, this activity is mediated by the delta-hemolysin, coded by the hld gene within the agr locus. In S. lugdunensis, the equivalent activity results from the production of 3 small peptides coded by an operon named slush, distinct from hld and located outside the agr region. We examined 15 clinically relevant staphylococcal species for the presence of hld, slush and agr by specific hybridisation. All species contained a recognizable agr-related locus. Three species never produced synergistic haemolysis and contained neither hld nor slush. Of the 12 producer strains, 5 contained hld, apparently within the agr region, 4 contained slush and one (S. caprae) contained both. Two other producer species (S. hominis and S. simulans) hybridised to neither probe.
Bacterial Proteins↗
Fulminant myocardial failure in a previously healthy young man.
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Adolescent↗
Multicenter clinical comparison of resin-containing bottles with standard aerobic and anaerobic bottles for culture of microorganisms from blood.
In a study comparing the Bactec 9240 (Plus Aerobic/F and Anaerobic/F bottles, containing resins; Becton Dickinson, USA) and the Vital (standard aerobic and anaerobic bottles, with no additives; bioMérieux, France) blood culture systems, 6456 sets of four bottles of 9660 blood cultures submitted were evaluated. There were 531 clinically significant isolates from 795 positive blood cultures. Of the 531 positive blood cultures, 355 were positive in both systems, 141 with the Bactec 9240 alone, and 30 with the Vital alone (p < 0.001); five were not detected by either system. The average time to detection of positive cultures for the matched sets was 10.65 h and 18.41 h by the Bactec 9240 system and the Vital system, respectively. The false-positive rate per bottle was 0.65% in the Bactec 9240 and 0.71% in the Vital. The rate of false-negative pairs (i.e., major errors) was very low (0.12% for the Bactec 9240, 0.19% for the Vital) and not significantly different between the two systems. The striking differences in recovery of microorganisms may be due to the presence of resins in the Bactec medium. However, the observed superiority of the Bactec 9240, even for patients not receiving antibiotics, suggests that resins adsorb other inhibitors present in patients' blood.
Adult↗
Evaluation of a commercial test kit for rapid detection of Staphylococcus aureus in blood cultures.
The presence of Staphylococcus aureus in positive blood cultures could be rapidly confirmed by the use of a commercial test kit (Rapidec Staph; bioMérieux, France) that detects coagulase in the culture broth after 2 h of incubation. This kit detected all 35 Staphylococcus aureus strains from 117 blood cultures with gram-positive cocci growing in clusters. The sensitivity and the specificity of the technique were 100% and 98.8%, respectively. The Rapidec Staph kit appears to be a simple and reliable technique for the rapid detection of Staphylococcus aureus in blood cultures.
Bacteremia↗