PubMed · 2490194
The source did not provide an abstract. Follow the original record for more information.
Explore connections, maps & timelines
G Klein. 1989. [Polymer fixed microorganisms for water processing].. https://pubmed.ncbi.nlm.nih.gov/2490194/
Cite the original work for its findings. Save a collection to share your selection of sources.
KEEP EXPLORING
We developed an in vitro model to study the temperature-regulated cytotoxicity and intracellular growth of Mycobacterium haemophilum in cultured human epithelial and endothelial cells. M. haemophilum associated with human epithelial and endothelial cells at similar rates when incubated at 33 and 37 degrees C, but only the epithelial cell line supported the multiplication of this organism. M. haemophilum grew equally well with epithelial cells at both temperatures. The aminoglycoside antibiotic amikacin was used to study the intracellular growth of M. haemophilum in the epithelial cells at 33 and 37 degrees C. Although an approximately equal number of bacteria were found within cells after 2 days of incubation at both temperatures, intracellular replication of M. haemophilum was 1,000-fold greater at 33 than at 37 degrees C. This intracellular multiplication was associated with destruction of the monolayers at 33 but not at 37 degrees C, and only culture filtrates from infected monolayers incubated at 33 degrees C were cytotoxic to fresh epithelial cell monolayers. This strain of M. haemophilum also produced contact-dependent hemolysis of sheep erythrocytes, demonstrating the possible presence of a cytolysin. These studies suggest that M. haemophilum has a preference for growth with cultured human epithelial cells. In addition, intracellular growth is best at 33 degrees C in epithelial cells, and this correlated with cytotoxicity at this temperature. This phenotype may be caused by induction of a soluble cytotoxic component, possibly a hemolytic cytolysin.
Pollution by pathogenic bacteria was examined in 150 French metalworking fluid samples. Gram-negative micro-organisms such as Salmonella spp., Shigella spp., and Vibrio spp. as well as Gram-positive cocci were never isolated. Nevertheless opportunistic pathogens such as Pseudomonas aeruginosa and Klebsiella pneumoniae still contaminated these fluids with an isolation frequency of 17% of samples for each. These two micro-organisms failed to grow or even survive in vitro in sterile cutting fluids protected by biocides. Preliminary growth of other micro-organisms such as Pseudomonas putida or Pseudomonas fluorescens, which are the major part of the indigenous microflora, seemed to be a prerequisite for their growth. These former two Pseudomonas could resist three different classes of biocides and, at least in the case of formaldehyde-releasers, adaptation was followed by biocide deterioration. Resistance magnification was observed in the presence of the three different types of biocides and, in the case of formaldehyde releasers the resistance and deterioration levels were close to those recommended by the manufacturers. This is probably the reason why the preliminary growth of Pseudomonas putida allowed in vitro differed growth of Klebsiella pneumoniae and Pseudomonas aeruginosa. Due to relatively high isolation frequencies of opportunistic pathogens (17% of samples) periodical microbiological examination of cutting fluids should be carried out in order to evaluate risks for human health. Wearing masks and gloves is still recommended, at least in France.
The effects in vitro of both teicoplanin and vancomycin of blood peripheral human neutrophils have been studied by assays of antibiotic uptake and intracellular killing of previously phagocytosed Staphylococcus aureus. The effects of vancomycin and teicoplanin (a novel glycopeptide antibiotic), at the therapeutic concentrations reached in plasma (10, 25, 50, 75 and 100 mg/l) and at different times of incubation (5, 15, 30 and 60 min) were studied. The results indicate that: (1) the bactericidal effect of neutrophils increases with incubation time, (2) in the presence of both teicoplanin and vancomycin, the number of CFU/ml of intraphagocytic S. aureus declines with both increasing incubation time and exposure dose of the antibiotics and (3) at 100 mg/l of teicoplanin there is a significant increase in the percentage inhibition of S. aureus growth at all the times studied.