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At least 307 records · Page 17Linked to original sources
PubMed1988

Differences in aerosol survival between pathogenic and non-pathogenic strains of Legionella pneumophila serogroup 1.

A strain of Legionella pneumophila serogroup 1 known to be virulent for guinea-pigs was found to be least stable at a relative humidity (r.h.) of 60% when stored as a small particle aerosol. Three L. pneumophila serogroup 1 strains of different virulence for guinea-pigs were then tested at a r.h. of 60% at 20 degrees C. The most virulent strain was found to have the best survival and the avirulent strain was least stable. The strain of intermediate virulence did not survive as well as the virulent strain but was more stable than the avirulent strain. Strains of L. pneumophila serogroup epidemiologically associated with legionnaires' disease had better survival in small particle aerosols than strains which were not associated with disease. Subtyping with monoclonal antibodies also showed that the type more commonly associated with disease survived longer in aerosols than the other subtypes.

Aerosols↗
PubMed1989

Flotation of mastitis pathogens with cream from subclinically infected quarters. Prospects for developing a cream-rising test for detecting mastitis caused by major mastitis pathogens.

Bacterial isolates, originating from 36 subclinically infected quarter milk samples, were labelled with 75Se and checked for cream-rising at various temperatures in a system analogous to the ABR test ("Abortus Bang Ringprobe"; the cream-rising test based on stained brucella organisms for detection of brucellosis). Diagnostic specificity and sensitivity were analyzed in experiments where labelled bacterial isolates were mixed with a number of quarter milk samples with known bacteriological status as well as samples from healthy control quarters. Creaming at 37 degrees C resulted in specific "recognization" as the bacterial isolates showed preferential flotation in the milk samples from which they had been isolated as well as is milk samples harbouring the same bacterial species. At lower creaming temperatures, the specificity was lost since all the isolates became concentrated in the cream phase irrespective of the milk sample. When comparing the specific recognization by cream of the respective bacteria, bacterial species vary: The prospects for developing diagnostic cream-rising tests for Streptococcus agalactiae, Staphylococcus aureus and Escherichia coli seems promising, but less so for coagulase-negative staphylococci, Streptococcus dysgalactiae, and Streptococcus uberis. The mechanism behind the cream-rising of labelled bacteria at 37 degrees C seems to lie in specific fat globule membrane-bound immunity of IgA type. Therefore the milk fat globules from chronically infected quarters function as absorbents for the respective isolates. Flotation of bacteria with cream indicates an in vivo mechanism enabling bacteria to invade the upper parts of milk ducts within the udder.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1998

[Differentiation and characterization of yeasts pathogenic for humans (Candida albicans, Exophiala dermatitidis) and algae pathogenic for animals (Prototheca spp.) using Fourier transform infrared spectroscopy (FTIR) in comparison with conventional methods].

Due to the Fourier-Transform Infrared Spectroscopy (FT-IR) of strain specific traits demonstrated to be a suitable and efficient method for diagnostic and epidemiological determinations for the yeasts Candida albicans, Exophiala dermatitidis and the chlorophylless algae of the genus Prototheca. FT-IR leads in a rapid and economical way to reproducible results according to the spectral differences of intact cells (IR-fingerprints). Different genera, species and sub-species respectively, different strains can be recognized and grouped into different clusters and subclusters. The FT-IR analysis of Candida albicans isolates (n = 150) of 22 newborns-at-risk of an intensive care unit showed, that 86% of the children were colonised with several (2-4) different strains in the oral cavities and faeces. Stationary cross-infections could definitely be determined. Exophiala dermatitidis isolates (n = 31), mostly isolated repetitively within a period of 3 years from sputa of patients suffering from cystic fibrosis could be characterized and grouped patient-specifically over the total sampling period. Of 6 from 8 patients (75%) their individual strains remain the same and could be tracked over the three years. Cross-infections during the stationary treatment could be clearly identified by FT-IR. The Prototheca isolate (n = 43) from live-stock and farm environment showed clear distinguishable clusters differentiating the species P. wickerhamii, P. zopfii and P. stagnora. In addition, the biotypes of P. zopfii could be distinguished, especially the subclusters of variants II and III. It could be demonstrated, that FT-IR is suitable for the routine identification and differentiation of yeasts and algae. However, in spite of the gain of knowledge by using FT-IR for the characterization of microorganisms, the conventional phenotyping and/or genetic analysis of yeast or algae strains cannot be replaced completely. For a final taxonomic classification a combination of conventional methods on FT-IR together with more sophisticated molecular genetic procedures is necessary.

Animals↗
PubMed1985

Relationship between growth inhibition and mitochondrial function in petite-negative yeasts. I. Effects of antibiotics and dyes upon pathogenic and non-pathogenic Candida species.

Antibiotics and dyes which preclude growth of Saccharomyces cerevisiae in media containing oxidizable carbon sources arrested the growth of Candida albicans, Candida tropicalis and Candida utilis even in glucose medium. The growth in the presence of sub-inhibitory concentrations of the various antibiotics and dyes determined a reduction in the cell survival but with no accumulation of respiratory deficient mutants. Under these culture conditions, the total respiration declined leaving a residual antimycin A-resistant--hydroxamate-sensitive O2 uptake, and the amount of the respiratory cytochromes aa3 and b synthesized was reduced. SDS gel electrophoresis of soluble proteins prepared from the antibiotic-treated cells showed some bands in the MW range 92-100 K, which became faint after the cells were grown in the presence of some mitochondrial inhibitors. The ultrastructural analysis of these cells evidenced disappearance of the mitochondrial cristae and their replacement by unfolded membranes. The data obtained suggest that the petite negative trait of Candida could depend on the non-viability or on the very low viability of those cells which have lost their mitochondrial function.

Anti-Bacterial Agents↗
PubMed1985

Relationship between growth inhibition and mitochondrial function in petite-negative yeasts. II. Effects of central nervous system drugs upon pathogenic and non-pathogenic Candida species.

Six nervous system drugs which inhibited vegetative reproduction of S. cerevisiae arrested also mitotic division of C. utilis, C. albicans and C. tropicalis. Chlorpromazine and chlorpheniramine which proved to be the most effective, affected respiration and cytochrome biosynthesis. Electrophoretic bands with MW congruent to 100 K were faint in silver-stained electrophoregrams of proteins from cells grown in the presence of a sub-inhibitory concentration of chlorpromazine.

Amitriptyline↗
PubMedDate not supplied

In vitro nail invasion by pathogenic and non-pathogenic fungi under different culture conditions.

Data from the literature suggest that the nutritional environment can modify major metabolic functions of fungi and possibly their aggressivity towards keratinous structures. Trichophyton rubrum (TR), Microsporum canis (MC), Scopulariopsis brevicaulis (SB), Aspergillus fumigatus (AF) and Penicillium spec. (P) were inoculated on media of different nutritional value, in presence of nail fragments. The activity of the fungi was evaluated at two and four weeks for intensity and depth of invasion of nail samples. Nail invasion was most pronounced by MC, especially when grown on rice agar or peptone agar. Nail invasion by the other fungi tested was less important, Sabourand glucose and rice agar were most favorable. Our results indicate that nutritional factors can, at least in some fungus species, alter their rate of nail invasion.

Aspergillus fumigatus↗