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At least 127 records · Page 7Linked to original sources
PubMed1994

Detection of microbial surface antigens that bind Lewis(a) antigen.

There is evidence that the Lewis(a) blood group antigen is one of the receptors for a number of potentially pathogenic microorganisms. To determine how widely distributed the microbial adhesins are that bind this antigen, anti-idiotypic antibodies produced against monoclonal anti-Lewis(a) were used in coagglutination assays to screen a variety of species. The following were agglutinated: 7/7 strains of Staphylococcus aureus; 10/19 (53%) strains of Neisseria meningitidis; 8/13 (62%) strains of Haemophilus influenzae; 1/3 strains of Helicobacter pylori; 1/2 strains of Neisseria gonorrhoeae; 1/2 strains of Candida albicans. The application of the anti-idiotypic antibodies to studies of host cell receptors, isolation of adhesins and development of new epidemiological typing reagents is discussed.

Adhesins, Bacterial↗
PubMed1983

Detection of microbial proteolytic activity by a cultivation plate assay in which different proteins adsorbed to a hydrophobic surface are used as substrates.

A screening technique for microbial proteases, the thin-layer enzyme assay cultivation technique, was developed. The inner surface of a polystyrene petri dish was coated with protein and then covered with a culture agar medium. The enzymes, produced during growth of the microorganisms, reach the protein-coated surface by diffusion in the agar. Degradation of the protein was visualized by condensation of water vapor on the surface after removal of the agar medium. The wettability of the enzyme-affected protein-coated polystyrene surface was decreased compared with the unaffected protein surface. Enzyme substrates used were fibrinogen, immunoglobulin G, egg albumin, human serum albumin, bovine serum albumin, hemoglobin, mucin, and gelatin. It was possible to use a variety of culture agar media, nonselective as well as selective, in the assay. The technique provides a sensitive, convenient, and inexpensive method for screening various microbial proteases. In addition, the technique can be used for screening proteolytic enzyme activity of specific microbial species in a mixed microbial sample as well as for studies of factors that influence the cultivation conditions for protease production and activity.

Bacteria↗
PubMed1979

Particle size distribution analysis for the rapid detection of microbial infection of urine.

The accuracy and practicality of particle size distribution analysis for rapid screening of urine specimens are assessed. Six hundred urines were subjected simultaneously to routine bacteriological examinations and particle size distribution analysis using a Coulter Counter (ZBI) linked to a C1000 Channelyzer. There was complete agreement in the results of 593 (98.8%) specimens. Characteristic profiles of various bacterial species in infected specimens were consistently obtained. This system can easily be linked to any existing computer reporting in a district hospital laboratory, and the results of negative specimens (70--80%) can be obtained within 5--10 minutes.

Bacteriological Techniques↗
PubMed2005

Relationship between antenatal inflammation and antenatal infection identified by detection of microbial genes by polymerase chain reaction.

Although antenatal infection is thought to play an important role in the pathogenesis of preterm labor and neonatal diseases, the exact mechanisms are largely unknown. We sought to clarify the relationship between antenatal infection and intrauterine and neonatal inflammation. Samples were obtained from 41 preterm infants of <33 wk gestation delivered to 36 mothers and analyzed for the presence of 16s ribosomal RNA (16s rRNA) genes using PCR and for the proinflammatory cytokines IL-6 and IL-8. In 16 (44%) mother-baby pairings, at least one sample was found to be positive for the presence of 16s rRNA genes. All but one of the positive samples were from mothers presenting with preterm prelabor rupture of membranes (pPROM) or in spontaneous idiopathic preterm labor. A strong association was found between the presence of 16s rRNA genes and chorioamnionitis and with funisitis. A marked increase in IL-6 and IL-8 was noted in all tissues positive for 16s rRNA genes, including placenta, fetal membranes, cord blood serum, and, where samples were available, in bronchoalveolar lavage fluid (BAL) and in amniotic fluid. Interestingly, gastric fluid was always positive for 16s rRNA genes if any other intrauterine or BAL sample was positive, suggesting that this sample may provide an alternative to amniotic fluid to identify antenatal infection. In conclusion, we have found that microbial genes are particularly prevalent in pPROM and spontaneous preterm labor groups and that their presence is strongly associated with a marked intrauterine inflammatory response.

Amniotic Fluid↗
PubMed2001

[Contribution to the early diagnosis of bacteremia: microbial growth detection in liquid culture media by ultrasound].

Nosocomial infection is an important problem because the number of patients daily affected in big hospitals. A big effort exists to develop techniques able to early detect the micro-organisms which cause the infection. The ultrasound is a mechanical radiology technique widely used in Medicine for diagnosis and therapy. It is also well known that this radiation can be used to control relative changes of several physico-chemical parameters in liquids. As an example, the velocity an attenuation of acoustic waves coming through a liquid can be accurately measured. The developed technique consists of an ultrasonic chamber immersed into a thermostatized water bath with two transducers operating in through-transmission. Different culture bottles were placed in between the transducers to live the ultrasound to come across the sample. Several micro-organisms with controlled concentrations, chosen between the most common in sepsis clinical, were used to inoculate each bottle. In the case of aerobic metabolism, the carbon dioxide gas produced by bacteria introduce elastic changes into the liquid which modify both the propagation velocity and the attenuation of the ultrasound. The continuous monitoring of the time-of-flight and the amplitude of an ultrasonic pulse coming through the sample give us a clear indication of the metabolism process. The signatures observed permits the identification of algorithms to early define the positive cases. The developed technique is faster than other commercial systems. The intrinsically non-invasive characteristic of the ultrasound and the relative cheapness of the technique open new attractive possibilities in microbiological diagnosis.

Bacteremia↗
PubMedDate not supplied

[Comamonas testosteroni strain TI as a potential base for a microbial sensor detecting surfactants].

Strain Comamonas testosteroni TI, capable of degrading the nonionic surfactant (NIS) nonylphenolethoxylate (OP-10), was used for constructing a pilot cellular biosensor. The lower NIS detection limit for the biosensor was 0.25 mg/l. We studied the substrate specificity of the biosensor with respect to a wide range of organic compounds: surfactants, polyaromatic compounds (PAC), carbohydrates, alcohols, etc. It was shown that the biosensor based on Comamonas testosteroni TI did not respond to glucose, which was an advantage over the formerly described biosensor based on Pseudomonas rathonis T. The amplitude of the sensor response remained stable for 10 days.

Biosensing Techniques↗
PubMed1990

Detection of microbial trypsin-like enzymes by use of an agar gel.

Certain oral micro-organisms associated with periodontal diseases elaborate trypsin-like enzymes. This study describes a single assay for these enzymes, based on the incorporation of the synthetic substrate N-alpha-benzoyl-DL-arginine-p-nitroanilide (BAPNA) into ion-agar gel. The system can provide quantitative or qualitative data within 24 h and is suitable for use in the dental clinic.

Arginine↗
PubMed1979

Blood cultures with the BACTEC 225 radiometric microbial growth detection system.

The BACTEC 225 automated radiometric blood culture system was compared with a conventional blood culture bottle method for its ability to improve the rapid laboratory diagnosis of bacteremia in cancer patients. The BACTEC 225, in combination with routine blind subcultures and smears of radiometrically negative culture vials, detected two thirds, of all positive cultures within 24 h and shortered the detection time generally by 24-48 h. With the recommended growth index setting of 30, radiometrically false-positive findings are rare and are usually due to leukocytosis resulting from infection or leukemia.

Bacteriological Techniques↗