Use of a radiorespirometric assay for testing the antibiotic sensitivity of catheter-associated bacteria
A /sup 14/C-radiorespirometric assay was used to show the sensitivity of fixed-film (sessile), catheter-associated and free-living (planktonic) cells of Pseudomonas aeruginosa to varying concentrations (100 micrograms/mL to 1000 micrograms/mL) tobramycin sulfate. This strain of P. aeruginosa has an MIC of 0.6 microgram/ml and an MBC of 50 micrograms/mL when tested by conventional methods. When /sup 14/C-glutamic acid was used as a substrate in this radiorespirometric assay, it could be completed in less than one hour and planktonic samples showed a significant reduction in mineralization activity (evolution of /sup 14/CO/sub 2/) within eight hours of the antibiotic challenge. These changes in respiratory activity appeared to be dose and time dependent. Within 18 hr. at 1000 micrograms/mL, there was no significant residual respiratory activity in planktonic samples. Some residual respiratory activity was detected, however, in samples exposed to 100 micrograms/mL for 36 hours. The mineralization activity of sessile catheter-associated bacteria was unaffected by four hr. and eight hr. exposures to 1000 micrograms/mL of the antibiotic. A significant reduction in respiratory activity was recorded in catheter samples exposed for 18 hr. or more at each concentration examined. Unlike the planktonic samples, however, the antibiotic challenge failed to eradicate the metabolic activity of the attached bacteria. Antibiotic stressed, catheter-associated bacteria transferred to a post-exposure enrichment broth showed a limited ability to re-establish respiratory activity. This apparent recovery was limited to antibiotic exposures less than 24 hr. and was not observed in planktonic samples. The radioisotopic assay is a non-culture method which can be used to assess the antibiotic sensitivity of both planktonic bacteria and in situ biofilm populations.
- Research Organization:
- Univ. of Calgary, Alberta
- OSTI ID:
- 5603952
- Journal Information:
- J. Urol.; (United States), Vol. 138:6
- Country of Publication:
- United States
- Language:
- English
Similar Records
A Peptide Derived from Phage Display Library Exhibits Antibacterial Activity against E. coli and Pseudomonas aeruginosa
UAF radiorespirometric protocol for assessing hydrocarbon mineralization potential in environmental samples
Related Subjects
ANTIBODIES
RADIOASSAY
PSEUDOMONAS
SENSITIVITY
UROGENITAL SYSTEM DISEASES
PATHOGENESIS
CARBON 14 COMPOUNDS
CARBON DIOXIDE
DOSE-RESPONSE RELATIONSHIPS
GLUTAMIC ACID
RESPIRATION
SULFATES
TIME DEPENDENCE
AMINO ACIDS
BACTERIA
CARBON COMPOUNDS
CARBON OXIDES
CARBOXYLIC ACIDS
CHALCOGENIDES
DISEASES
LABELLED COMPOUNDS
MICROORGANISMS
ORGANIC ACIDS
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
SULFUR COMPOUNDS
550901* - Pathology- Tracer Techniques