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[Bacterial growth in the perfusion medium of the isolated rat brain and its inhibition by antibiotics]
Abstract:
In the perfusion medium of the isolated rat brain the bacterial content was examined. The perfusion medium used contained 30% bovine erythrocytes, 2 g% bovine serum albumin and about 13 mM glucose in Krebs-Henseleit-solution. Before the perfusion of the isolated rat brain was started the medium recirculated up to two hours in the perfusion apparatus. After this, the perfusion of the isolated rat brain was carried out for four hours. At various times and at different points of the circulating system samples of the perfusion medium were withdrawn and tested for their bacterial content. Using the plate count procedure, at the end of the perfusion 10(5) to 10(6) bacteria per ml medium were found. This order of magnitude of the bacterial content suggested that it is not necessary to add antibacterial substances to the medium when perfusions lasted up to 4 hours. Nevertheless, from each sample 10 bacteria species were isolated and their sensitivity against 15 different antibacterial substances was tested. The substances were ampicillin, carbenicillin, cephaloridine, chloramphenicol, cloxacillin, erythromycin, gentamycin, nalidixic acid, neomycin, nitrofurantoin, penicillin, polymyxin B, sulfadiazine, tetracycline and trimethoprim + sulfamethoxazole. Tetracycline was most active in inhibiting bacterial growth. 1 mg and 0.5 mg tetracycline added to 100 ml perfusion medium were able to prevent an increase of the bacterial count during the perfusion experiments.
Insights
Bacterial contamination in isolated rat brain perfusion medium reached 10^6 CFU/mL. Tetracycline effectively inhibited bacterial growth, suggesting its potential use in perfusion experiments.
Area of Science:
- Neuroscience
- Microbiology
- Pharmacology
Background:
- The use of isolated organ perfusion systems is crucial for studying physiological and pharmacological responses.
- Bacterial contamination in perfusion media can confound experimental results and compromise organ viability.
- Understanding bacterial dynamics and effective control strategies is essential for reliable perfusion studies.
Purpose of the Study:
- To investigate the bacterial content in the perfusion medium of isolated rat brains.
- To assess the efficacy of various antibacterial agents against isolated bacterial species.
- To determine optimal conditions for maintaining bacterial control during isolated rat brain perfusion.
Main Methods:
- Isolated rat brains were perfused using a medium containing bovine erythrocytes, bovine serum albumin, and glucose in Krebs-Henseleit-solution.
- Perfusion medium was recirculated for up to 2 hours before and 4 hours during perfusion.
- Bacterial content was quantified using plate count procedures, and isolated species were tested for sensitivity to 15 antibacterial agents.
Main Results:
- Bacterial counts in the perfusion medium reached 10^5 to 10^6 CFU/mL by the end of 4-hour perfusion.
- Tetracycline demonstrated the highest activity in inhibiting bacterial growth among the tested agents.
- Low concentrations of tetracycline (0.5-1 mg/100 mL) prevented bacterial proliferation during perfusion.
Conclusions:
- Significant bacterial proliferation occurs in isolated rat brain perfusion media within 4 hours.
- Tetracycline is a highly effective agent for controlling bacterial growth in this context.
- The findings suggest that adding tetracycline to the perfusion medium can maintain sterility and ensure reliable experimental outcomes.