An electron microscopic study of the effect of clindamycin on adherence of Staphylococcus aureus to bone surfaces.

Discs of rabbit tibia, 5 mm thick, were utilized to study the adherence of Staphylococcus aureus to the bone surface in the presence and absence of clindamycin. Bacteria were grown in broth media containing the bone slices and varying concentrations of clindamycin. In the absence of the antibiotic, S. aureus adhered extensively to bone surfaces and formed large microcolonies which were surrounded by an amorphous matrix. In the presence of 0.025 micrograms/ml of clindamycin (0.1 MIC), S. aureus adhered less to bone surfaces, forming smaller and fewer microcolonies. In the presence of 0.0625 micrograms/ml of clindamycin (0.25 MIC), S. aureus adhered to the bone surfaces only sparsely, forming small microcolonies with very little matrix holding them together, and leaving very large areas of the bone surface uncolonized. In the presence of 0.125 micrograms/ml of clindamycin (0.5 MIC), bone surfaces were basically clean, with only one or two cells (no microcolonies) found in crevices and indentations of the bone surface. In the presence of 0.25 micrograms/ml (1 MIC) no bacteria adhered to the bone surfaces.

Studies on the hygiene of drinking water for laboratory animals. 1. The effect of various treatments on bacterial contamination.

Daily autoclaving of drinking-water bottles or daily replacement of their contents resulted in drinking water hygienically acceptable for laboratory rats. However, daily autoclaving of the bottles imposes an additional workload which many institutions cannot afford. The daily replacement of the drinking water is not desirable, since with the usual routines it is virtually impossible to guarantee a bottle is returned to the same cage. A reliable method of preventing bacterial growth for more then 1-2 days in the drinking water of conventional laboratory rats is its acidification with hydrochloric acid to pH 2.3-2.5.

Studies on the hygiene of drinking water for laboratory animals. 2. Clinical and biochemical studies in rats and rabbits during long-term provision of acidified drinking water.

The reaction of rats and rabbits to long-term application of acidified drinking water (pH 2.3-2.5) was observed over a 7-months period. The following parameters were studied: growth curves initiated at weaning, haematology, blood glucose, total serum protein, creatinine, inorganic phosphate, sodium, potassium, calcium, alkaline phosphatase, creatinine kinase, serum glutamate oxalacetate transaminase, and serum glutamate pyruvate transaminase in serum as well as the acid-base status in arterial blood; in addition in rabbits gamma-glutamyl transferase and lactate dehydrogenase were examined in the serum. No significant changes were seen in comparison to the control groups.