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Biomedical subjects

J Freney

Publications and source records attributed to J Freney.

106 records · Page 6Linked to original sources

Nosocomial infection and colonization by Klebsiella trevisanii.

During an 18-month period we identified two cases of septicemia and 24 examples of colonization of humans by Klebsiella trevisanii. Organisms were identified using the API 20EC and API 147 assimilation galleries. Of 147 clinical isolates initially identified as K. oxytoca, 18% were found to be K. trevisanii. Tracheal aspirate was the most common source of the organism. An extensive environmental sampling survey in the rooms of 12 colonized patients revealed a possible reservoir of the organism only once (a face cloth).

Aged↗

[Retroperitoneal actinobacteriosis caused by Haemophilus actinomycetemcomitans].

A 15 years old boy was admitted to the hospital for high fever, and a four month history of abdominal pain and weight loss. Clinical examination showed painful swelling of the left lumbar region. A retro peritoneal mass was revealed by tomodensitometry. There was a marked biological inflammatory syndrome without bacteriological evidence of infectious disease. Final diagnosis was performed by surgery showing a big abscess. Bacteriological culture of pus was positive for a Haemophilus actinomycetemcomitans.

Abscess↗

Septicemia caused by Agrobacterium sp.

Agrobacterium radiobacter biovar 2 was repeatedly grown from the blood of an elderly patient receiving artificial ventilation and broad-spectrum antibiotics. No source of the organism was found, but the septicemia ceased when cefotaxime was given. Sera from the patient showed a fourfold rise in antibody against the organism and higher titers than sera from all but 1 of 50 healthy blood donors. The organism did not contain the plasmid associated with plant oncogenicity. This case may be only the second in which Agrobacterium sp. has been clearly linked with human infection.

Aged↗

Differentiation of Enterobacteriaceae and Vibrionaceae by a micromethod for determination of carbon substrate assimilation.

The assimilation techniques described for taxonomic study are unsuitable for routine diagnosis because of the need for purification and standardization of substrates, the great quantity of medium consumed and difficulties in interpreting the results. A standardized micromethod (API strip) for the study of carbon substrate assimilation by bacteria has recently been described (Zbl. Bakt. Hyg., I. Abt. Orig. A 255 (1983) 479-488). The prototype gallery used consisted of two strips of 32 microtubes each containing dehydrated carbon substrate. Each strip contained 30 tests plus positive and negative controls. The suspension medium was a synthetic semi-gel. A total of 914 strains of Gram negative rods representing 44 species of Enterobacteriaceae and Vibrionaceae were tested (Table 1). Automatic reading was performed after incubation at 32 degrees C for one day, or two days for slow growing bacteria using an ATB - 1500 reader (API System) linked to a HP 85 microcomputer (Hewlett-Packard). Most species showed typical carbon substrate assimilation patterns allowing their differentiation from other species within each genus (Table 2). The results obtained with the micromethod agreed in large measure with the nutritional patterns reported by other workers. It should be possible to use these results to construct a coherent framework of tests suitable for identifying species of Enterobacteriaceae and Vibrionaceae of clinical significance.

Bacteriological Techniques↗

Differentiation of gram negative rods other than Enterobacteriaceae and Vibrionaceae by a micromethod for determination of carbon substrate assimilation.

The assimilation techniques described for taxonomic study are unsuitable for routine diagnosis because of the need for purification and standardization of substrates, the great quantity of medium consumed and difficulties in interpreting the results. A standardized micromethod (API Strip) for the study of carbon substrate assimilation by bacteria has recently been described (Zbl. Bakt. Hyg., I. Abt. Orig. A 255 (1983) 479-488). The prototype gallery used consisted of two strips of 32 microtubes each containing dehydrated carbon substrate. Each strip contained 30 tests plus positive and negative controls. The suspension medium was a synthetic semi-gel. A total of 1046 strains of Gram-negative rods representing 41 species belonging to the genera Pseudomonas, Alcaligenes, Moraxella, Acinetobacter, Flavobacterium and to the EF4 group were tested (Tables 1 to 6). Automatic reading was performed after incubation at 32 degrees C for one day, or two days for slow growing bacteria, using an ATB 1500 reader (API System) linked to a HP 85 microcomputer (Hewlett-Packard). Most species showed typical carbon substrate assimilation patterns allowing their differentiation from other species within each genus. The results obtained with the micromethod agreed in large measure with the nutritional patterns reported by other workers. It should be possible to use these results to construct a set of tests suitable for identifying species of Gram-negative rods other than Enterobacteriaceae and Vibrionaceae.

Acinetobacter↗

Nosocomial colonization and infection by Achromobacter xylosoxidans.

Achromobacter xylosoxidans, a bacterial species named in 1971, is often isolated from aqueous environments, but little has been reported about its pathogenicity in humans, its epidemiological pattern, and its susceptibility to antibiotics and antiseptics. We were faced with an epidemic caused by this microorganism for 18 months in an intensive care unit. Two patients had fatal infections and 37 others were colonized. The source was the deionized water of the hemodialysis system. The 46 isolates were identified by comparison with the reference strain A. xylosoxidans ATCC 27061. The characteristic cellular fatty acids of this species were demonstrated by gas-liquid chromatography. The minimal inhibitory concentrations of 27 antibiotics were determined. The isolates were susceptible to only two: moxalactam at 4 micrograms/ml and ceftazidime at 8 micrograms/ml. The minimal bactericidal concentrations of one disinfectant and three antiseptics were: sodium hypochloride, 109 micrograms/ml; chlorhexidine digluconate in ethanol solution, 15 to 125 micrograms/ml; polyvinylpyrrolidone iodine, 750 micrograms/ml; and iodine ethanol, 312 to 625 micrograms/ml.

Alcaligenes↗

[Comparison of 2 systems for identifying nonfermenting or fermenting oxidase-positive gram-negative bacilli].

The N/F FLOW and API 20 NE identification systems were compared for their ability to identify 182 strains of either non-fermentative or fermentative oxidase-positive gram-negative bacilli. Agreement with the identification given by conventional methods was achieved for 91,7 per cent of strains by the API System but for only 81,9 per cent of strains by the N/F System. Complementary tests were needed to identify 35,4 per cent of strains using the API System but 65,2 per cent using the N/F System.

Bacteriological Techniques↗

[Effect of storage time at -20 degrees C on the determination of serum concentrations of tobramycin in the presence of 6 beta-lactams].

We assessed the role of six beta-lactam antibiotics and of storage time at - 20 degrees C, in inactivation of tobramycin in patients' sera. Several ranges of concentrations were used for the combined antibiotics. The tobramycin concentrations were measured both by microbiological assay (plate diffusion) and an enzyme mediated immunoassay technique (EMIT). Using the bioassay method, the results after 8 days of frozen storage were as follows: carbenicillin and ticarcillin (256 mg/l) induced a 40-50% reduction of tobramycin activity, whereas mezlocillin (256 mg/l) had less effect: a 15-20% reduction. After 15 days at -20 degrees C the results were nearly the same except for azlocillin (256 mg/l), increasing its percentage reduction to 20%. The results obtained by EMIT procedure were significantly better after 8 days of frozen storage: only mezlocillin (5% reduction) and azlocillin (10%) were effective. Nevertheless after 15 days at -20 degrees C, the inactivating action of the pre-cited antibiotics were similar to those obtained at the same time with the bioassay method. Piperacillin and cefsulodin never induced any reduction of tobramycin levels, whatever the time of storage or quantification procedure used. So, our opinion is that patients' sera containing a beta-lactam antibiotic in combination with tobramycin should be assayed immediately upon receipt. Keeping it at -20 degrees C is not sufficient to prevent in vitro tobramycin inactivation.

Anti-Bacterial Agents↗

[Value of the study of fibrinogen affinity in the identification of Staphylococcus aureus. Results of a multicenter study].

The passive haemagglutination reaction for detecting the Staphylococcus aureus fibrinogen affinity was done in a collaborative study. The test was compared to the major tests used in medical microbiology. The test was as efficient as the protein A or coagulase tests. Its simplicity, rapidity and specificity make it a useful tool for the diagnosis of this species.

Fibrinogen↗

Micromethod for carbon substrate assimilation by Pseudomonas maltophilia.

Assimilation of 60 carbon sources by 114 Pseudomonas maltophilia strains, identified by conventional methods, was studied by a standardized micromethod (API strip). Automatic reading of growth intensity was done at 1, 2 and 4 days. Growth kinetics of reference strain NCTC 10257 were also studied and showed evidence of different growth according to the substrates. The results agreed well with nutritional patterns reported. This micro-method seems suitable for daily use by laboratories because of purity and standardization of substrates, facility of use, accurate and automatic reading, and the great number of assimilation tests possible.

Amino Acids↗

Rapid isolation of DNA from Actinomyces.

DNA could not be quickly extracted from members of the genus Actinomyces by the usual methods of lysis. Treatment of 7 different actinomyces cells with lysozyme and achromopeptidase, both 5 mg/g wet cells, for 2 h, followed by SDS (0.2%), proteinase K (5 mg/g wet cells) and EDTA (lmM) for 1 h, lysed the cells. The yield obtained in one day was 337 micrograms per 200 mg of bacterial cells. The treatment was also found to work effectively on strains belonging to Veillonella, Staphylococcus, Fusobacterium and Bifidobacterium genera.

Actinomyces↗

[Fast tests in bacteriology].

Advances in biotechnologies and miniaturization over the past few decades have led to an explosion in the number of rapid tests in in vitro diagnosis and explain their ever-growing presence in international markets. Although based on classic immunological and biochemical methods, these tests deliver many more benefits for laboratories. They are rapid and simple to perform, provide results rapidly and can be performed in remote laboratories, making them invaluable for both routine and emergency analyses. As beneficial as they may be, however, they still have a long way to go before they find widespread use in infectious disease control. Currently, rapid testing methods are used only to screen for urinary tract infections, monitor certain infectious parameters and make more accurate diagnosis of a still small number of species of bacteria. This narrow catalogue of available tests is yet another disadvantage in a list of drawbacks typically associated with rapid tests. A good portion of complaints centers on the fact that they are still too recent to have sufficient information on their levels of sensitivity and reliability. Furthermore, regulations, in particularly concerning accountability, remain to be established. Nevertheless, constant innovation coupled with the experience of laboratory professionals in the field should open the way for rapid testing to earn its place in the line-up of medical laboratory tests.

Bacterial Infections↗

[Extraction of chromosomal DNA from Staphylococcus and Listeria by a rapid method using achromopeptidase].

A rapid and simple method for preparation of chromosomal DNA from Gram-positive bacteria is reported. Susceptibility to lysis with Sodium Dodecyl Sulfate (SDS) increases when undergoing treatment with acetone before being digested by bacteriolytic enzymes. Rapid lysis of Staphylococcus and Listeria cells is obtained through a respective treatment by lysozyme with lysostaphine and by lysozyme with achromopeptidase, adding to that the effect of SDS in Tris-Hcl buffer. This procedure of preparing chromosomal DNA provides 1 to 4 mg of DNA out of 1 g of bacterial cells in a day.

Chromosomes↗