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S Bonacorsi

Publications and source records attributed to S Bonacorsi.

At least 19 recordsLinked to original sources
PubMed2006

Escherichia coli native valve endocarditis.

Among 36 cases of Escherichia coli native valve endocarditis (NVE) that met Duke criteria (31 cases in the literature between 1909 and 2002, and five cases seen in Paris, France), the urinary tract was the most common portal of entry. The majority (72.2%) of cases developed in elderly females. Overall, the proportion of patients aged > 70 years rose from 5.3% in 1982 to 22.9% in 2002. Persistent E. coli bacteraemia in the elderly in the absence of cardiac risk-factors may be a sign of NVE and should prompt an investigation by echocardiography.

Age Factors↗
PubMed2004

Outbreak of Burkholderia cepacia bacteremia in a pediatric hospital due to contamination of lipid emulsion stoppers.

We describe a 7-month outbreak of nosocomial Burkholderia cepacia bacteremia involving eight children in a pediatric hospital and the results of epidemiological investigations. A B. cepacia strain genotypically identical to the blood isolates was recovered from the upper surface of capped rubber stoppers of bottles of a commercial lipid emulsion used for parenteral nutrition.

Bacteremia↗
PubMed2001

The Yersinia high-pathogenicity island is highly predominant in virulence-associated phylogenetic groups of Escherichia coli.

The high-pathogenicity island (HPI) present in pathogenic Yersinia and encoding the siderophore yersiniabactin, has recently been identified in the asnT tRNA region of various Escherichia coli pathotypes, especially those responsible for bacteremia and urosepsis. Most E. coli strains causing such extra-intestinal infections belong to phylogenetic groups B2 and D. In this study we investigated (i) the distribution and localization of HPI among the different E. coli phylogenetic groups, using the ECOR reference collection; and (ii) the prevalence of HPI among a set of 124 phylogenetically characterized E. coli strains responsible for neonatal meningitis. Ninety-three percent of the ECOR strains belonging to groups B2 and D harbored HPI. In contrast, the island was present in 32% and 25% of strains belonging to groups A and B1, respectively, which are considered to be non-pathogenic. HPI was found in 100% of the neonatal meningitis strains, 13 of which belonged to groups A and B1, suggesting that HPI might contain virulent factors required for the development of neonatal meningitis. Moreover, we observed for the first time that HPI can be inserted in a site different from the asnT tRNA region.

Bacterial Outer Membrane Proteins↗
PubMed2001

Genotypic characterization of Pseudomonas aeruginosa strains recovered from patients with cystic fibrosis after initial and subsequent colonization.

Chronic infection by Pseudomonas aeruginosa (PA) in patients with cystic fibrosis (CF) is preceded by a period of colonization and acute infection. Early aggressive antibiotic treatment of initial colonisation may prevent or at least delay chronic pulmonary infection. We initiated treatment with a combination of IV beta-lactam tobramycin, followed by nebulized colistin when PA was first isolated from patients with CF. Subsequent serial PA isolates obtained from these colonized CF patients were characterized by means of molecular methods to determine whether they were genetically related to the initial strain. Initial colonization was eradicated in all 19 patients. All patients reacquired PA within 3-25 months during the 3 years of follow-up. Fourteen patients acquired a new PA strain with a distinct genotypic profile, suggesting a new source of contamination. Five patients had two PA isolates with identical genotypes, suggesting either previous undetected respiratory tract colonization or a persistent environmental source of contamination.

Administration, Inhalation↗
PubMed2001

[Virulence factors associated with E. coli neonatal meningitis].

Escherichia coli K1 is the leading cause of gram-negative bacterial meningitis in neonates. It is associated with a mortality rate as high as 40%, and more than half of the survivors have neurologic sequelae. Bacterial meningitis is the result of bacterial translocation from gastrointestinal tract to the blood and from blood to the central nervous system. Successful crossing of the BBB by E. coli K1 requires (a) a high degree of bacteremia and (b) several E. coli determinants contributing to invasion of BMEC such as the K1 capsule, Sfa, Ibe proteins, and CNF1. A better understanding for the molecular basis of E. coli K1 penetration of the BBB could potentially lead to the development of novel therapeutic and preventative strategies for E. coli K1 meningitis.

Blood-Brain Barrier↗
PubMed2001

Mechanisms of macrolide resistance in clinical group B streptococci isolated in France.

Macrolide susceptibility was investigated in clinical group B streptococci obtained from neonates or pregnant women in 2000 in France. Of 490 consecutive isolates, 18% were resistant to erythromycin. The erm(B), erm(A) subclass erm(TR), and mef(A) genes were harbored by 47, 45, and 6% of these strains, respectively. Two isolates did not harbor erm or mef genes.

Anti-Bacterial Agents↗
PubMed2001

Automated ribotyping provides rapid phylogenetic subgroup affiliation of clinical extraintestinal pathogenic Escherichia coli strains.

Using the automated Riboprinter system, we have initiated the construction of an electronic Riboprint database composed of 72 ECOR reference strains and 15 archetypal virulent strains in order to provide a new simple molecular characterization method. More than 90% of the ECOR strains clustered in their original phylogenetic group. All but one of the archetypal virulent strains had a profile identical to that of one of the ECOR strains and could be easily affiliated with a phylogenetic group. This method appears to be an accurate and practical tool especially for investigating the genetic relationship between clinical extraintestinal pathogenic strains and B2 subgroup ECOR strains or archetypal pathotype strains.

Bacteremia↗
PubMed2001

Metabolism of [(14)C]omapatrilat, a sulfhydryl-containing vasopeptidase inhibitor in humans.

Omapatrilat, a potent vasopeptidase inhibitor, is currently under development for the treatment of hypertension and congestive heart failure. This study describes the plasma profile along with isolation and identification of urinary metabolites of omapatrilat from subjects dosed orally with 50 mg of [(14)C]omapatrilat. Only a portion of the radioactivity in plasma was unextractable (40-43%). Prominent metabolites identified in plasma were S-methyl omapatrilat, acyl glucuronide of S-methyl omapatrilat, and S-methyl (S)-2-thio-3-phenylpropionic acid. Omapatrilat accounted for less than 3% of the radioactivity. However, after dithiothreitol reduction all of the radioactivity was extractable and was characterized to be omapatrilat and its hydrolysis product (S)-2-thio-3-phenylpropionic acid, both apparently bound to proteins via reversible disulfide bonds. Urinary profile of radioactivity showed no parent compound but the presence of several metabolites that can be grouped into three categories. 1) Three metabolites, accounting for 56% of the urinary radioactivity, resulted from the hydrolysis of the exocyclic amide bond of omapatrilat. Two metabolites were diastereomers of S-methyl sulfoxide of (S)-2-thio-3-phenylpropionic acid, and the third was the acyl glucuronide of S-methyl (S)-2-thio-3-phenylpropionic acid. 2) One disulfide, identified as the L-cysteine mixed disulfide of omapatrilat, accounted for 8% of the radioactivity in the urine. 3) Five metabolites, derived from omapatrilat, accounted for 30% of the radioactivity in the urine. Two of these metabolites were mixtures of diastereomers of S-methyl sulfoxide of omapatrilat and the third was the S-methyl omapatrilat ring sulfoxide. The other two metabolites were S-methyl omapatrilat and its acyl glucuronide. These results indicate that omapatrilat undergoes extensive metabolism in humans.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed2000

Rapid and simple determination of the Escherichia coli phylogenetic group.

Phylogenetic analysis has shown that Escherichia coli is composed of four main phylogenetic groups (A, B1, B2, and D) and that virulent extra-intestinal strains mainly belong to groups B2 and D. Actually, phylogenetic groups can be determined by multilocus enzyme electrophoresis or ribotyping, both of which are complex, time-consuming techniques. We describe a simple and rapid phylogenetic grouping technique based on triplex PCR. The method, which uses a combination of two genes (chuA and yjaA) and an anonymous DNA fragment, was tested with 230 strains and showed excellent correlation with reference methods.

Electrophoresis, Polyacrylamide Gel↗
PubMed1999

Comparative in vitro activities of meropenem, imipenem, temocillin, piperacillin, and ceftazidime in combination with tobramycin, rifampin, or ciprofloxacin against Burkholderia cepacia isolates from patients with cystic fibrosis.

We evaluated the activities of meropenem, imipenem, temocillin, piperacillin, and ceftazidime by determination of the MICs for 66 genotypically characterized Burkholderia cepacia isolates obtained from the sputum of cystic fibrosis patients. In vitro synergy assays, as performed by the time-kill methodology, of two- and three-drug combinations of the beta-lactams with tobramycin, rifampin, and/or ciprofloxacin were also performed with 10 strains susceptible, intermediate, or resistant to fluoroquinolones. On the basis of the MICs, meropenem and temocillin were the most active beta-lactam agents, with MICs at which 90% of isolates are inhibited of 8 and 32 micrograms/ml, respectively. The addition of ciprofloxacin significantly enhanced the killing activities of piperacillin, imipenem, and meropenem against the 10 strains tested (P < 0.05). The best killing activity was obtained with the combination of meropenem and ciprofloxacin, with bactericidal activity of 3.31 +/- 0.36 log10 CFU/ml (P < 0.05). Compared to the activity of the two-drug beta-lactam-ciprofloxacin combination, the addition of rifampin or tobramycin did not significantly increase the killing activity (P > 0.05). The three-drug combinations (with or without ciprofloxacin) significantly enhanced the killing activities of piperacillin, imipenem, and meropenem relative to the activities of the beta-lactams used alone (P < 0.05). The combination beta-lactam-ciprofloxacin-tobramycin was the combination with the most consistently synergistic effect.

Burkholderia Infections↗
PubMed1998

Comparative in vitro killing activities of meropenem, imipenem, ceftriaxone, and ceftriaxone plus vancomycin at clinically achievable cerebrospinal fluid concentrations against penicillin-resistant Streptococcus pneumoniae isolates from children with meningitis.

The activities of meropenem, imipenem, ceftriaxone, and vancomycin were evaluated against 80 penicillin-susceptible and -resistant Streptococcus pneumoniae strains. Meropenem, imipenem, ceftriaxone, and vancomycin MICs at which 90% of the isolates are inhibited were 0.5, 0.25, 1, and 0.25 microg/ml, respectively. Against penicillin-resistant strains, the best killing activity at cerebrospinal fluid concentrations was obtained with imipenem and ceftriaxone-vancomycin. However, while the killing activity of imipenem was significantly greater than that of meropenem, no significant difference was observed between the activities of meropenem and ceftriaxone-vancomycin.

Anti-Bacterial Agents↗
PubMed1998

[Multiresistant bacteria in pediatrics].

Microorganisms that are resistant to multiple antimicrobial agents are of great concern to pediatric clinicians. Children infected with antibiotic-resistant bacteria are at risk to not respond to initial therapy. Nosocomial infection of pediatric patients with multidrug-resistant organisms are similar to those found in adults especially for Staphylococcus aureus, coagulase-negative staphylococci, vancomycin resistant Enterococcus and Enterobacteriaceae resistant to third-generation cephalosporin. However on the contrary to adult patients, multidrug-resistant bacteria are found in community infections with penicillin-resistant Streptococcus pneumoniae and P. aeruginosa in CF patients.

Bacteria↗
PubMed1997

Molecular markers for differentiation of multiresistant Klebsiella pneumoniae isolates in a pediatric hospital.

OBJECTIVE: To study the spread of extended-spectrum beta-lactamase-producing, but aminoglycoside-susceptible, Klebsiella pneumoniae strains in our hospital over an 8-month period, by using two genotypic markers. DESIGN: Ribotyping (using two endonucleases) and randomly amplified polymorphic DNA analysis (RAPD; using two different 10-mer primers) were applied to the epidemiological typing of clinical K pneumoniae isolates from stools, ileal fluid, or urine of hospitalized children. SETTING AND PATIENTS: The surgical intensive-care ward (S1: 9 patients, 17 isolates), surgical unit (S2: 2 patients, 2 isolates), and gastroenterology ward (GE: 1 patient, 1 isolate) of the Robert Debré Hospital of Paris, France. RESULTS: Ribotyping of the 20 clinical isolates, the type strain of the species, and two epidemiologically unrelated isolates with EcoRI and HindIII revealed 6 and 5 different patterns, respectively. Six ribotypes were identified by using these two enzymes. RAPD generated 6 distinct patterns, in complete agreement with ribotyping. Our genotypic results showed that 11 patients from wards S1, S2, and GE harbored genotypically related strains, suggesting nosocomial transmission and cross-colonization between and within the three wards. CONCLUSIONS: Ribotyping and RAPD appear to be reliable methods for distinguishing K pneumoniae strains. The spread of one strain of K pneumoniae in different units of our hospital was demonstrated by both methods. However, RAPD has the advantage of simplicity and rapidity conferred by polymerase chain reaction.

Cross Infection↗
PubMed1997

Bactericidal activity against intermediately cephalosporin-resistant Streptococcus pneumoniae in cerebrospinal fluid of children with bacterial meningitis treated with high doses of cefotaxime and vancomycin.

Cerebrospinal fluid (CSF) was taken from 19 children with bacterial meningitis treated with cefotaxime (300 mg/kg of body weight/day) and vancomycin (60 mg/kg/day). Median levels of drugs in CSF were smaller than expected, as follows: 4.4 microg/ml for cefotaxime, 3.2 microg/ml for desacetylcefotaxime, and 1.7 microg/ml for vancomycin. The median CSF bactericidal titer against an intermediately cefotaxime-resistant pneumococcus was 1:4. Our data suggest at least an additive interaction between the drugs used in this study.

Adolescent↗
PubMed1997

Virulence patterns of Escherichia coli K1 strains associated with neonatal meningitis.

The prevalence of the ibe10 gene, of the pap, afa, and sfa adhesin-encoding operons, and of a 14.9-kb rrn-containing HindIII fragment was studied for 67 Escherichia coli neonatal meningitis strains, 58 E. coli K1 commensal strains, and 47 E. coli blood isolates from neonates without meningitis. ibe10, sfa, and the 14.9-kb HindIII fragment were observed significantly more often in the meningitis strains than in blood or commensal strains.

Adhesins, Bacterial↗
PubMed1996

In-vitro activity of teicoplanin and ceftriaxone in combination against pathogens involved in paediatric bone and joint infections.

We investigated the combination of teicoplanin and ceftriaxone for its bactericidal activity against Staphylococcus aureus, Haemophilus influenzae type b and Streptococcus pneumoniae isolated from bone and joint infections in children. An increase in bactericidal activity was observed against isolates of S. aureus and H. influenzae when the antibiotics were tested at fractional MICs whereas indifference was observed at their MICs. Similar results were obtained at fractional MICs against S.pneumoniae, but the bactericidal activity fell by more than 1 x log 10 cfu/mL when the antibiotics were tested at or above their MICs.

Bacterial Infections↗
PubMed1996

Molecular epidemiology provides evidence of genotypic heterogeneity of multidrug-resistant Pseudomonas aeruginosa serotype O:12 outbreak isolates from a pediatric hospital.

Ribotyping randomly amplified polymorphic DNA analysis, and pulsed-field gel electrophoresis were used for the epidemiologic evaluation of eight Pseudomonas aeruginosa O:12 isolates obtained from eight children and two P. aeruginosa O:12 environmental isolates from a hematology ward. Randomly amplified polymorphic DNA analysis and pulsed-field gel electrophoresis were able to discriminate isolates that were indistinguishable by biochemical typing, O serotyping or ribotyping.

Adolescent↗