Anderson, Elaine M. (1988). The Effect of Growth Conditions on B-lactam Resistance in Enterobacter Cloacae. PHD thesis, Aston University.
Abstract
The nutritional requirements of Enterobacter cloacae E7 (a clinical isolate) were quantitatively defined using a chemically defined medium (CDM). E.cloacae strains E12, E13,E14 and E16 (also clinical isolates) grew in this medium at similar growth rates to E7. Antibiotic sensitivity patterns were determined for these five strains of E.cloacae. Bacteria grown in Iso-sensitest broth, urine and serum were generally 2-8 fold less sensitive than those grown in nutrient deprived CDM. The effect of growth medium and rate on β-lactamase production and on induction of B-lactamase by cefotaxime was examined. Growth medium and rate had no significant effectupon β-lactamase production in the absence of β-lactam antibiotics. However growth rate profoundly affected β-lactamase induction by cefotaxime. Faster growing bacteria produced greater levels of β-lactamase activity insignificantly less time than slower growing bacteria. Expression of porin proteins and iron regulated membrane proteins (IRMPs), in different media, was subject to variation both within and between strains of E.cloacae. However there was no correlation between expression of these outer membrane proteins and growth medium, nor was there any correlation between expression of porin proteins and antibiotic susceptibility. Growth in iron-deprived CDM, urine and serum and growth in phosphate deprived CDM (CDM-P)induced the expression of IRMPs in E.cloacae. Penicillin-binding proteins (PBPs) 5 and 6 of E.cloacae were sensitive to changes in the growth medium, particularly in serum and CDM-P. Further investigations are required to determine the effect of growth medium on the higher molecular weight PBPs.
| Publication DOI: | https://doi.org/10.48780/publications.aston.ac.uk.00012557 |
|---|---|
| Divisions: | College of Health & Life Sciences |
| Additional Information: | Copyright © Elaine Marie Anderson, 1988. Elaine Marie Anderson asserts their moral right to be identified as the author of this thesis. This copy of the thesis has been supplied on condition that anyone who consults it is understood to recognise that its copyright rests with its author and that no quotation from the thesis and no information derived from it may be published without appropriate permission or acknowledgement. If you have discovered material in Aston Publications Explorer which is unlawful e.g. breaches copyright, (either yours or that of a third party) or any other law, including but not limited to those relating to patent, trademark, confidentiality, data protection, obscenity, defamation, libel, then please read our Takedown Policy and contact the service immediately. |
| Institution: | Aston University |
| Uncontrolled Keywords: | growth conditions,B-lactam resistance,Enterobacter cloacae |
| Last Modified: | 03 Apr 2025 10:45 |
| Date Deposited: | 24 Jan 2011 11:29 |
| Completed Date: | 1988-09 |
| Authors: |
Anderson, Elaine M.
|