[Resistance to the latest beta-lactams: mechanisms of acquisition and spread of resistance in Enterobacteriaceae].

Resistance to antibiotics may drastically diminish the efficacy of therapy in some clinical circumstances. The emergence of Enterobacteriaceae (Klebsiella pneumoniae, Aerobacter aerogenes, Escherichia coli) resistant to the more recent beta-lactam agents (cefepime, cefpirome, azthreonam and carbapenems) generally results from misuse of antibiotics, leading to the selection of preexisting resistant mutants. Resistance is usually due to beta-lactamase expression, through: -- mutations involving the beta-lactamase structure (TEM, SHV, OXA, CTX-M beta-lactamase families) and/or mutations of beta-lactamase synthesis regulators (AmpC beta-lactamases); or -- the appearance of new enzymes (PER, VEB, CMY, DHA-1, ACC-1, etc.

The pyocins of Pseudomonas aeruginosa.

Pyocins are produced by more than 90% of Pseudomonas aeruginosa strains and each strain may synthesise several pyocins. The pyocin genes are located on the P. aeruginosa chromosome and their activities are inducible by mutagenic agents such as mitomycin C.

Uptake of pyocin S3 occurs through the outer membrane ferripyoverdine type II receptor of Pseudomonas aeruginosa.

Pyocin S3 was found to kill exclusively Pseudomonas aeruginosa isolates producing type II pyoverdine (exemplified by strain ATCC 27853). Killing was specifically inhibited by addition of type II ferripyoverdine. All Tn5 mutants resistant to pyocin S3 were defective for pyoverdine-mediated iron uptake and failed to produce an 85-kDa iron-repressed outer membrane protein.

Genotypic analysis of Burkholderia cepacia isolates from 13 French cystic fibrosis centers.

Burkholderia cepacia has been involved in outbreaks of pulmonary infection among patients with cystic fibrosis (CF), and the spread of a highly transmissible clone has been reported throughout the United Kingdom and Canada. These data prompted a DNA-based typing study of the strains recovered in French CF centers. Ninety-five isolates recovered from 71 patients attending 13 CF centers in 9 regions of France were characterized by randomly amplified polymorphic DNA (RAPD) analysis and pulsed-field gel electrophoresis (PFGE).

Dechlorination of Atrazine by a Rhizobium sp. Isolate.

A Rhizobium sp. strain, named PATR, was isolated from an agricultural soil and found to actively degrade the herbicide atrazine. Incubation of PATR in a basal liquid medium containing 30 mg of atrazine liter(sup-1) resulted in the rapid consumption of the herbicide and the accumulation of hydroxyatrazine as the only metabolite detected after 8 days of culture.

Pulsed-field gel electrophoresis as an epidemiological tool for clonal identification of Aeromonas hydrophila.

Pulsed-field gel electrophoresis (PFGE) was used to characterize Aeromonas hydrophila strains isolated from a cluster of hospital-acquired infections that occurred over approximately 1 month in a French hospital. Five isolates from patients and 10 isolates from the water supply were characterized by biotyping and antibiotic susceptibility patterns and compared with 10 epidemiologically unrelated strains isolated from patients and rivers, by PFGE of digests of chromosomal DNA. Five environmental and four clinical isolates belonged to the same biotype and antibiotic susceptibility pattern type.

Discriminatory power and usefulness of pulsed-field gel electrophoresis in epidemiological studies of Pseudomonas aeruginosa.

We assessed the discriminatory power of pulsed-field gel electrophoresis (PFGE) for the analysis of DNA restriction fragment length polymorphism (RFLP) in Pseudomonas aeruginosa. We determined DraI PFGE-RFLP of DNA of unrelated clinical and environmental strains, and clinical strains isolated from two intensive care units of the Besançon University Hospital. The typeability and reproducibility was 100%.

Use of pulsed-field gel electrophoresis as an epidemiologic tool during an outbreak of Pseudomonas aeruginosa lung infections in an intensive care unit.

Objective: A retrospective study was performed to evaluate the use of DNA polymorphism analysis by pulsed-field gel electrophoresis (PFGE) in assessing the rate of exogenous contamination during an outbreak of Pseudomonas aeruginosa lung infections in an intensive care unit ICU. Another goal was to determine the risk factors, involved in the outbreak.

Design: Rectal swabs and tracheal secretions were cultured from all patients upon admission and thereafter once a week throughout their stay in the ICU.

Use of pulsed-field gel electrophoresis for investigation of an outbreak of Clostridium difficile infection among geriatric patients.

A six-month outbreak of Clostridium difficile infection among elderly residents of a middle-term-care facility was investigated. Pulsed-field gel electrophoresis was used to genotype 22 outbreak strains and 30 epidemiologically unrelated strains. A prospective case-control study was conducted to identify risk factors for epidemic Clostridium difficile-associated diarrhea.

[Pseudomonas aeruginosa septicemia. Host-related risk factors in 82 episodes].

Objectives: The prognosis of septicaemia due to Pseudomonas aeruginosa is severe with mortality ranging from 32 to 73%. We retrospectively studied 82 episodes in order to determine whether risk factors could be identified.

Methods: Eighty-two episodes of Pseudomonas aeruginosa septicaemia, observed between 1986 and 1991, were analyzed.

Risk factors for nosocomial colonization with multiresistant Acinetobacter baumannii.

A six-month prospective survey was carried out in a university hospital to assess the incidence of Acinetobacter baumannii cross-contamination and to identify risk factors for colonization. Clinical isolates obtained during the study period were biotyped and genotyped by pulsed-field gel electrophoresis after ApaI macrorestriction of total DNA. Case-control univariate and multivariate analyses were performed to identify risk factors for Acinetobacter baumannii colonization.

Nasal carriage of Staphylococcus aureus and cross-contamination in a surgical intensive care unit: efficacy of mupirocin ointment.

A six month prospective study was carried out in a surgical intensive care unit (SICU) of a university hospital to assess the incidence and routes of exogenous colonization by Staphylococcus aureus. A total of 157 patients were included in the study. One thousand one hundred and eleven specimens (nasal, surgical wound swabs, tracheal secretions obtained on admission and once a week thereafter, and all clinical specimens) were collected over a four month period from patients without nasal decontamination (A).

Molecular characterization of pyocin S3, a novel S-type pyocin from Pseudomonas aeruginosa.

The genetic determinant for the soluble pyocin S3 was isolated from a genomic library constructed in the plasmid pGV1122, of Pseudomonas aeruginosa strain P12 isolated from a cystic fibrosis patient. The nucleotide sequence of a 3270-base pair DNA fragment was determined, and the two structural genes, pyoS3A and pyoS3I, and the 3'- and 5'-flanking regions were localized. Transcription (Northern blot) analysis showed that the two genes were co-transcribed.

[Listeriosis in patients with malignant hemopathy. 3 cases in the same hospital ward].

During the listeriosis epidemic which occurred in France in the summer 1992, three patients with malignant haematopathies hospitalized in our service contracted the disease. Although the retrospective investigations were hindered by the variable incubation period and the impossibility of examining the foods eaten at the time of infection, there was a high probability that two of the patients had been infected by cooked ham and dairy products at home. The third patient was apparently infected in hospital with well-cooked food found to be contaminated.

[Organ culture preservation of the human cornea at +31 degrees C and risk of infection].

Purpose: In order to reduce the risk of infection, we analyzed each stage of conservation of human cornea in organ culture at +31 degrees C.

Methods: This epidomiological study was conducted in 266 human corneas preserved in organ culture between January 1991 and December 1993. There were 3 stages: In the period of preservation (analysis of the contaminated medium), Before clinical use of the graft (analysis of the preservation medium), After the penetrating keratoplasty (analysis of the corneo-scleral rim and the transportation medium).

Typing of hospital strains of Xanthomonas maltophilia by pulsed-field gel electrophoresis.

We report the use of pulsed-field gel electrophoresis (PFGE) to characterize Xanthomonas maltophilia isolates from an incident of hospital-acquired infection over a 12-day period in a haematological unit. Ten isolates from five patients (from throat, urine, stool and blood) and two isolates from environmental sites in the unit were compared with 10 epidemiologically unrelated clinical strains, isolated over a 3-month period from several units in two hospitals, by PFGE of DraI digests of chromosomal DNA. The profiles obtained were stable, reproducible and discriminatory.

Cloning and characterization of the Inc A/C plasmid RA1 replicon.

The Inc A/C plasmids, like Inc P and Inc Q plasmids, have a broad host range. However, their maintenance functions remain to be studied. An autoreplicative region of 2.

Fluconazole-resistant recurrent oral candidiasis in human immunodeficiency virus-positive patients: persistence of Candida albicans strains with the same genotype.

Thirty human immunodeficiency virus-positive patients carrying Candida albicans in their oropharynx were treated with fluconazole and were monitored for 90 to 570 days. Fluconazole-resistant C. albicans (MIC, > 32 micrograms/ml) appeared only in seven patients and only after 90 days of treatment corresponding to a total dose of more than 10 g.

Replicon typing of 71 multiresistant Serratia marcescens strains.

Replicon typing is the identification of plasmids by hybridization with specific DNA probes which contain the genes involved in plasmid maintenance. This new method has been used to classify plasmids into replicon (rep) groups which can often be correlated with incompatibility (Inc) groups. We studied 71 multiresistant Serratia marcescens strains with 19 rep probes constructed from reference plasmid replicons belonging to known Inc groups.

Characterization of a novel extended-spectrum beta-lactamase from Pseudomonas aeruginosa.

A clinical isolate of Pseudomonas aeruginosa RNL-1 showed resistance to extended-spectrum cephalosporins which was inhibited by clavulanic acid. Although this strain contained three plasmids ca. 80, 20, and 4 kb long, the resistance could not be transferred by mating-out assays with P.