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Biomedical subjects

J Freney

Publications and source records attributed to J Freney.

At least 19 recordsLinked to original sources
PubMed2006

Using an efficient biofilm detaching agent: an essential step for the improvement of endoscope reprocessing protocols.

Biofilms develop inside endoscope channels even when valid endoscope reprocessing protocols are applied. The use of an efficient biocide is not sufficient if the channels are not cleaned thoroughly prior to disinfection. This study compared new anti-biofilm combinations of detachment promoting agents with a cleaning product in current use. Tests were performed using Teflon tubing and a contamination device that reproduces conditions that are prevalent during endoscopy. Products were subjected to static+brushing or dynamic treatments, and their ability to remove a preformed biofilm was assessed. The residual biofilm after treatment was assessed and compared with untreated controls. The percentage of surface covered by biofilm was measured after staining with crystal violet. Culturable bacteria levels were determined by plating the bacteria scraped from the tubing surface and counting the colony-forming units (CFU). Further tests were performed on actual endoscopes that had been contaminated artificially. Biofilm removal was confirmed by scanning electron microscopy. This study showed that the new anti-biofilm products prevented the build-up of biofilm and removed a mature biofilm (approximately 10(8)CFU/cm(2)), whereas protocols based on detergent-disinfectants containing quaternary ammonium compounds showed low efficacy as these protocols and products fixed the biofilm on the endoscope surfaces. The new procedure and agents represent a new approach to biofilm control that may improve the efficacy of endoscope reprocessing, and reduce the risk of transmitting infections.

Biofilms↗
PubMed2006

[Bacterial adhesion to intraocular lenses and endophthalmitis prevention: review of the literature].

Bacterial adhesion to intraocular lenses (IOLs) during their implantation is a major etiological factor of postoperative endophthalmitis. Polypropylene was the first biomaterial that allowed this relation of cause and effect between bacterial adhesion and endophthalmitis to be proven. Adhesion to IOLs has been investigated in several in vitro studies, with contradictory results reported, due to variations in experimental conditions: the incubation times and the methods all varied. Adhesion is affected by the type of IOL, the bacterial strains, and the surrounding medium. Since this medium is very difficult to model because of its complexity, in vivo studies seemed essential. We have recently determined in vivo progression in the amount of adhering Staphylococcus epidermidis to five types of IOLs. There have been few epidemiological studies published to determine the relationship between endophthalmitis and the IOL type. However, the perfect biomaterial that could prevent postoperative endophthalmitis does not yet exist. Globally, hydrophilic materials and hydrophobic acrylic seem to be less sticky than silicone or PMMA, but this remains to be proven clinically.

Bacterial Adhesion↗
PubMed2005

Evaluation of the new Vitek 2 GN card for the identification of gram-negative bacilli frequently encountered in clinical laboratories.

The new Vitek 2 GN card (bioMérieux, Marcy-l'Etoile, France) was developed for better identification of fermenting and nonfermenting bacilli. This new card allows the identification of 159 taxa. A total of 426 isolates (331 fermenting and 95 nonfermenting gram-negative bacilli) belonging to 70 taxa covered by the database were evaluated. All isolates were identified in parallel with the ID 32 GN, the API 20E, and the API 20NE methods. The system correctly identified 97.4% (n=415) of the strains. Only 2.1% (n=9) needed additional testing. One strain (0.25%) was misidentified (Klebsiella pneumoniae subsp. pneumoniae), and another one (0.25%) was not identified (Morganella morganii subsp. morganii). The new GN card gives more accurate identifications overall for gram-negative bacilli when compared to the systems described in other similar studies.

Bacterial Typing Techniques↗
PubMed2005

[Staphylococcus epidermidis biofilms on intraocular lens surface: review of the literature].

Bacterial adhesion to intraocular lenses (IOLs) takes place during their implantation. This is a prominent etiological factor of postoperative endophthalmitis. Following adhesion, secretion of an extracellular matrix (called slime for Staphylococcus epidermidis) and formation of multiple layers of microcolonies lead to the colonization of the biomaterial surface. Scanning electron microscopy photographs illustrate the different steps of biofilm formation. The different adhesins expressed by S. epidermidis involved in the adhesion process are described. The biofilm is not only an adhesive medium; it also affects virulence. Last, notions on biofilm physiology are discussed in an attempt to explain the dynamic equilibrium of this system. In 2004, the perfect biomaterial able to prevent postoperative endophthalmitis does not yet exist. Moreover, there is no effective tool, at the present time, to fight against mature biofilms. Therefore, preventing biofilm formation remains capital, which requires perfect knowledge of all stages of formation and the factors involved.

Bacterial Adhesion↗
PubMed2005

[Endophthalmitis: pathogenesis and antibiotic prophylaxis].

Postoperative endophthalmitis is still one of the most fearsome complications of cataract surgery. The present review's aims are to study the etiology and pathogenesis of endophthalmitis and the criteria for antibiotic prophylaxis. Endophthalmitis prevalence is 0.07%-0.32% in cataract surgery. The clinical presentation needs to be perfectly known, even if none of the signs is pathognomonic. Bacteria predominantly cultured in postoperative endophthalmitis are gram-positive, especially Staphylococcus epidermidis. Most of the bacteria come from the patient. Bacterial adhesion to intraocular lenses (IOLs) takes place during their implantation, a prominent etiological factor. Polypropylene was the first biomaterial that proved this relation of cause and effect between bacterial adhesion and endophthalmitis. The benefit of antibiotic prophylaxis during cataract surgery has yet not been proven, since the low prevalence of endophthalmitis makes controlled studies with a large cohort difficult. The criteria and the four possible administration approaches (topical, subconjunctival, irrigation liquid, systemic) are analyzed.

Anti-Bacterial Agents↗
PubMed2004

Intraocular lenses, bacterial adhesion and endophthalmitis prevention: a review.

Postoperative endophthalmitis following intraocular lens (IOL) implantation is still one of the most feared complications of cataract surgery. Bacterial adhesion to IOLs during their insertion is a prominent etiological factor. Polypropylene was the first biomaterial that allowed this relation of cause and effect to be proven. Following adhesion, bacteria replicate, congregate and form multiple layers of microcolonies which actually represent the basic structural unit of the biofilm. The bacteria are embedded in a slime layer. Personal photographs illustrate the different steps of biofilm formation. This slime matrix is not only an adhesive medium; it also affects virulence. Adhesion to IOLs has been studied by several in vitro studies and discrepancies can be found between them which are due to variations of experimental conditions. The strains, the incubation times and the methods all varied. Adhesion is affected by the nature of the IOLs, the isolates and the surrounding medium. Since this medium is very difficult to model because of its complexity, in vivo studies seemed essential. We have recently determined in vivo evolution of the amount of attached bacteria to five types of IOLs. Crystalline lenses from 90 domestic pigs were removed aseptically and replaced with previously infected IOLs. There have been few epidemiological studies published to determine the relationship between endophthalmitis and the IOL type. However, the perfect biomaterial that could prevent postoperative endophthalmitis does not yet exist. Globally, hydrophilic materials and hydrophobic acrylic seem to be less sticky than silicone or PMMA, but this remains to be proven clinically.

Animals↗
PubMed2002

In situ decontamination of medical wastes using oxidative agents: a 16-month study in a polyvalent intensive care unit.

Over a 16-month period from September 1997 to December 1998, a prospective study was made of an on-site treatment of medical wastes in a 10-bed intensive care unit. First, the wastes were ground and then, a high concentration of ozone in air was repeatedly injected into the ground wastes. The study analysed the practical application of the system and its microbiological efficiency. Inactivation experiments were made with reference strains of Staphylococcus aureus, Enterococcus hirae, Pseudomonas aeruginosa, Escherichia coli, Mycobacterium smegmatis, Bacillus subtilis var niger, Bacillus stearothermophilus, Candida albicans and Aspergillus niger. Two thousand eight hundred treatment cycles, i.e. 84,000 grindings and 140,000 ozone injections gave a treatment capacity of 50 kg of waste per day with a good staff acceptability. All kinds of medical devices used in an intensive care unit were treated. In untreated ground wastes, the median bacterial load was 105.86 (range 10(2.35)-10(8.05)) cfu/g. After ozone treatment, bacteria and fungi were reduced by a factor of 10(5). Aero-contamination of the ward was unchanged. Computer control allowed all events to be tracked. On-site medical waste treatment appears to be an efficient alternative to the usual centralized collection and treatment.

Decontamination↗
PubMed2001

Identification of Brucella abortus, B. canis, B. melitensis, and B. suis by carbon substrate assimilation tests.

By using the results of seven carbon substrate assimilation tests from the Biotype 100 system (bioMérieux, Marcy-l'Etoile, France), we correctly identified 79 (85.9%) of 92 Brucella strains tested. The specificity of the method varied from 97.4 to 100% depending on the species. Although a biological safety cabinet must be used, this method represents an easy and fast alternative for the identification of Brucella species.

Bacterial Typing Techniques↗
PubMed2001

Molecular techniques open up new vistas for typing of coagulase-negative staphylococci.

Several methods were used to type 64 clinical isolates of coagulase-negative staphylococci (CNS) derived from hospitals in Morocco. The clinical isolates originated principally from blood cultures and wound sources. These isolates provided the opportunity to substantially compare the proficiency of developing molecular techniques with conventional phenotypic tests for use in the identification of clinical staphylococci. The following molecular methods were examined: Utility ribotyping analysis (Ribotyping); PCR analysis performed with 16S-23S ribosomal-DNA intergenic spacer (ITS-PCR); PCR-based random amplified polymorphic DNA (RAPD). The results obtained by the molecular techniques were contrasted to those of conventional phenotypic tests. Conventional phenotypic tests allowed the outright recognition of the majority of isolates (50/64). These 50 isolates were subdivided into 33 novobiocin-susceptible and 17 novobiocin-resistant strains of CNS. However, 2 other novobiocin-susceptible and 12 other novobiocin-resistant isolates remained unclassified by these tests. There was a good agreement between the conventional phenotypic tests and RAPD for the 33 novobiocin-susceptible isolates. But, the RAPD technique permitted the assignment of the two unidentified novobiocin-susceptible isolates to the Staphylococcus hominis species. A complete correlation was obtained between the three molecular tools for recognition of the 12 novobiocin-resistant isolates that were not identified by phenotypic typing; these were in fact identified as 5 Staphylococcus cohnii and 4 Staphylococcus equorum. Three isolates remained unidentified by all three systems of molecular techniques.

Bacterial Proteins↗
PubMed2001

Legionella gresilensis sp. nov. and Legionella beliardensis sp. nov., isolated from water in France.

Novel Legionella-like isolates, strains Montbéliard A1T and Gréoux 11 D13T, isolated from two different French water sources, were studied taxonomically and phylogenetically. Morphological and biochemical characterization revealed that they were Gram-negative, aerobic, non-spore-forming bacilli with a cut-glass appearance that grew only on L-cysteine-supplemented buffered charcoal yeast extract agar. Phenotypic characterization using fatty acid and ubiquinone profiles and SDS-PAGE analysis confirmed that they were closely related, but distinct from, other species of the genus Legionella, since serotyping could not relate them to any existing serogroup. Genotypic profiles generated by randomly amplified polymorphic DNA and 16S-23S rDNA spacer region PCR analyses were unique for each of these isolates. DNA-DNA relatedness values of strains Montbéliard A1T and Gréoux 11 D13T to each other and to other Legionella type strains were less than 25%. Phylogenetic affiliation of these organisms obtained by 16S rDNA sequence comparisons confirmed that they were distinct from any other known Legionella species. All the above results confirm that these strains constitute two novel species for which the names Legionella gresilensis sp. nov. (type strain Gréoux 11 D13T = ATCC 700509T = CIP 106631T) and Legionella beliardensis sp. nov. (type strain Montbéliard A1T = ATCC 700512T = CIP 106632T) are proposed.

Bacterial Proteins↗
PubMed2000

Improvement of the identification of staphylococci isolated from bovine mammary infections using molecular methods.

Fifty-six Staphylococcus strains isolated from cases of bovine mammary infections were identified by using phenotypic and genotypic methods. Twenty-eight strains (50%) were identified at the species level according to their phenotypic characteristics, whereas the remaining 28 strains presented atypical or unreliable profiles. A combination of phenotypic and genotypic methods allowed the 56 strains studied to be classified. Internal transcribed spacer-polymerase chain reaction (ITS-PCR) based on the polymorphism of the 16S-23S rDNA spacer region appeared as a rapid and reliable method for the classification of bovine staphylococcal isolates at the species and subspecies levels.

Animals↗
PubMed2000

Staphylococcus fleurettii sp. nov., isolated from goat's milk cheeses.

A new coagulase-negative and novobiocin-resistant species of the genus Staphylococcus, Staphylococcus fleurettii, isolated from raw-milk cheeses, is described. This species is differentiated from the other novobiocin-resistant staphylococci on the basis of ribotype and intergenic transcribed spacer patterns, DNA-DNA reassociation reactions, cell wall composition and phenotypic characteristics. S. fleurettii could be distinguished by its oxidase activity, by its ability to produce acid aerobically from D-trehalose, D-mannose, D-turanose and maltose and by its inability to produce acid from D-cellobiose. The type strain of S. fleurettii is CIP 106114T (= DSM 13212T).

Animals↗
PubMed2000

[Indicators of quality for hospital antisepsis].

In any health care institution, the most important quality indicator for antisepsis is the existence of systems of reference of use, secondly the knowledge of those systems and then the compliance by the different classes of professionals. These refrentials must be regularly evaluated and updated according to general consensus.

Antisepsis↗
PubMed1999

Pyrolysis-gas-liquid chromatography with atomic emission detection for the identification of Corynebacterium species.

We report here the application of pyrolysis-gas chromatography followed by atomic emission detection (AED) for the characterisation of microorganisms. AED measured the quantity of carbon, sulfur and nitrogen in the molecules separated chromatographically. Twenty-three strains, representing eight Corynebacterium species, were tested in this preliminary study. Co-ordinate principal analysis grouped 11 strains in their respective species group. Most of the other strains appear randomly distributed, perhaps because these strains require additional nutrients. These preliminary results show that the method could be used as a tool for the taxonomic and perhaps the epidemiologic characterisation of bacteria.

Carbon↗
PubMed1999

Clinical impact of rapid oxacillin susceptibility testing using a PCR assay in Staphylococcus aureus bactaeremia.

OBJECTIVES: The aim of this work was to establish the clinical impact of rapid oxacillin susceptibility testing in nosocomial Staphylococcus aureus bacteraemia. METHODS: This study was performed in 145 critically ill patients infected by S. aureus. Patients were randomly assigned to one of two groups: patients for whom susceptibility testing was performed using a rapid same day multiplex PCR assay for detection of the staphylococcal mecA (mean delay of response: 6 h) and those for whom testing was accomplished using traditional overnight techniques (21 h). RESULTS: The results of this study showed no significant difference between the two groups in terms of age, Simplified Acute Physiologic Score, severity of infection, severity of underlying disease and clinical outcome (control vs. PCR): unfavourable outcome of infection, 12.32 vs. 12.5%; 95% CI for the difference = -11.49 to 11.09 (P = 0.975); unfavourable general outcome, 16.43 vs. 20.83%; 95% CI for the difference = -17.35 to 8.50 (P = 0.497). For the oxacillin-susceptible S. aureus bactaeraemia, results were: unfavourable outcome of infection = 13.04 vs. 11.11%; 95% CI for the difference = -11.38 to 16.18 (P = 0.767); unfavourable general outcome = 13.04 vs. 20.37%; 95% CI for the difference = -22.12 to 8.07 (P = 0.331). CONCLUSION: This study seemed to demonstrate that rapid oxacillin susceptibility testing using a PCR assay did not have a major impact on the care and outcome of patients with S. aureus bactaeremia.

Adult↗