Metabolic and structural changes in Pseudomonas aeruginosa, Achromobacter CDC and Agrobacterium radiobacter cells...

The long term metabolic changes of three oxidase positive microorganisms (Pseudomonas aeruginosa, Agrobacterium radiobacter and Achromobacter CDC) all isolated from aquatic environment, were defined after they were inoculated in three parenteral fluids: Lactated Ringer's solution, Sodium Chloride 0.9% and Dextrose 5%. The number of microorganisms introduced into the parenteral products was adjusted to 10(5) bacteria/ml and left at room temperature (20-22 degrees C) for 30 days. Their enzymatic and protein profile as compared with their initial characteristics after they were grown in broth, were measured using API 20NE batteries of tests and gel electrophoresis. In L-R and NaCl 0.9% fluids, P. aeruginosa and Ag. radiobacter lost the ability to hydrolyse urea while Ac CDC retained this ability. In Dextrose 5% fluid the microorganisms lost most of their metabolic characters. The protein patterns in SDS-PAGE of samples prepared from cells of the tested microorganisms showed marked differences (in P. aeruginosa) to minor differences (in Ag. radiobacter and Ac CDC) while new proteins with M(r) > 66KDa revealed Ag. radiobacter cells. The gelatinolytic zymogram shows also differences between bacterial cells grown in nutrient broth and those that remained in parenteral fluids. These changes reflect the stress of the tested bacteria in an unfavorable condition. The alterations of injured bacteria could render them unable to grow on routine, for sterilization testing, culture media.