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A comparative study of the minimum inhibitory and mutant prevention concentrations of florfenicol and oxytetracycline for animal isolates of Pasteurella multocida and Salmonella Typhimurium
Dissertation (MSc)--University of Pretoria, 2012.
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University of Pretoria
2013
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| _version_ | 1867613518568620032 |
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| access_status_str | Open Access |
| author2 | Van Vuuren, Moritz |
| author_browse | Van Vuuren, Moritz |
| author_facet | Van Vuuren, Moritz |
| collection | Thesis |
| dc_rights_str_mv | © 2012 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria |
| description | Dissertation (MSc)--University of Pretoria, 2012. |
| format | Thesis |
| id | oai:repository.up.ac.za:2263/26219 |
| institution | University of Pretoria (South Africa) |
| last_indexed | 2026-06-10T12:37:25.592Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository |
| publishDate | 2013 |
| publishDateRange | 2013 |
| publishDateSort | 2013 |
| publisher | University of Pretoria |
| publisherStr | University of Pretoria |
| record_format | dspace |
| source_str | UPSpace — University of Pretoria Institutional Repository |
| spelling | oai:repository.up.ac.za:2263/26219 A comparative study of the minimum inhibitory and mutant prevention concentrations of florfenicol and oxytetracycline for animal isolates of Pasteurella multocida and Salmonella Typhimurium Van Vuuren, Moritz jeanettewentzel1@gmail.com Wentzel, Jeanette Maria Cattle Salmonella typhimurium Pasteurella multocida Horses Mutant prevention concentration (mpc) Pigs Minimum inhibitory concentration (mic) UCTD Dissertation (MSc)--University of Pretoria, 2012. This study was undertaken to compare the MIC (minimum inhibitory concentration) and MPC (mutant prevention concentration) values for oxytetracycline and florfenicol against strains of Pasteurella multocida isolated from cattle and pigs, and for enrofloxacin against strains of Salmonella Typhimurium isolated from horses. Isolates of P. multocida from cattle and pigs, and S. Typhimurium from horses were obtained from specimens or isolates from contributing laboratories. All the equine isolates and 50% of the cattle and pig isolates were from clinically sick animals. All isolates were tested in duplicate with both the MIC and the MPC methods. The MIC method used was the standardized microdilution method performed in microtitre plates. The MPC method used was according to the method described by Blondeau. This method was modified, to make use of smaller plates and lower volumes of antimicrobials, but retaining a final bacterial concentration of 109 colony-forming units per ml. The antimicrobials were dissolved as described in the certificates of analyses. Enrofloxacin and oxytetracycline were dissolved in water, and florfenicol was dissolved in alcohol. For the MPC method, an additional control was added to one quadrant of a four-quadrant 90mm plate/petri dish. The antimicrobials were tested as individual antimicrobials and not as combinations. Both the MIC and MPC methods included ATCC (American Type Culture Collection) strains as control organisms and were evaluated according to the guidelines of the CLSI (Clinical and Laboratory Standards Institute). The MIC50 values for enrofloxacin against Salmonella Typhimurium isolates from horses was 0.25 ìg/ml and the MPC50 values 0.5 ìg/ml. A comparative reference range was not available as enrofloxacin is not registered in South Africa for use in horses, and is used extra-labelly. The results for florfenicol against P. multocida yielded an MIC50 value of 0.5 ìg/ml and an MPC50 value of <2 ìg/ml. The close relationship of these two concentrations is an indication of the effectiveness of florfenicol when used against P. multocida. The PD/PK data with a value of 141.78 for AUC/MIC provided additional support for the efficacy of florfenicol against P. multocida. The PD/PK value of >125, is an effective parameter for treatment of Gram-negative bacteria. The corresponding results for oxytetracycline were above the MIC value but fell within the mutant selection window. The results point to the fact that the use of oxytetracycline against P. multocida may not be effective in preventing the appearance of first step mutant strains when used at current recommended dosages. The PK/PD data, using AUC/MIC, yielded a value of 56. Some of the isolates (55.17%) had an MPC value of 16 ìg/ml. Whereas the MIC method is used routinely in diagnostic laboratories, the MPC method can be employed to generate data that can be applied where antimicrobial treatment of certain bacteria is problematic and standard treatment may lead to the development of resistance. Data obtained from such studies will enable manufacturers of antimicrobial drugs to adapt antimicrobial therapy where practical and feasible to prevent the development of first step mutants. Veterinary Tropical Diseases unrestricted 2013-09-07T03:55:42Z 2013-07-31 2013-09-07T03:55:42Z 2013-04-12 2012 2013-07-11 Dissertation Wentzel, JM 2012, A comparative study of the minimum inhibitory and mutant prevention concentrations of florfenicol and oxytetracycline for animal isolates of Pasteurella multocida and Salmonella Typhimurium, MSc dissertation, University of Pretoria, Pretoria, viewed yymmdd < http://hdl.handle.net/2263/26219 > F13/4/677/gm http://hdl.handle.net/2263/26219 http://upetd.up.ac.za/thesis/available/etd-07112013-131057/ © 2012 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria application/pdf University of Pretoria |
| spellingShingle | Cattle Salmonella typhimurium Pasteurella multocida Horses Mutant prevention concentration (mpc) Pigs Minimum inhibitory concentration (mic) UCTD A comparative study of the minimum inhibitory and mutant prevention concentrations of florfenicol and oxytetracycline for animal isolates of Pasteurella multocida and Salmonella Typhimurium |
| title | A comparative study of the minimum inhibitory and mutant prevention concentrations of florfenicol and oxytetracycline for animal isolates of Pasteurella multocida and Salmonella Typhimurium |
| title_full | A comparative study of the minimum inhibitory and mutant prevention concentrations of florfenicol and oxytetracycline for animal isolates of Pasteurella multocida and Salmonella Typhimurium |
| title_fullStr | A comparative study of the minimum inhibitory and mutant prevention concentrations of florfenicol and oxytetracycline for animal isolates of Pasteurella multocida and Salmonella Typhimurium |
| title_full_unstemmed | A comparative study of the minimum inhibitory and mutant prevention concentrations of florfenicol and oxytetracycline for animal isolates of Pasteurella multocida and Salmonella Typhimurium |
| title_short | A comparative study of the minimum inhibitory and mutant prevention concentrations of florfenicol and oxytetracycline for animal isolates of Pasteurella multocida and Salmonella Typhimurium |
| title_sort | comparative study of the minimum inhibitory and mutant prevention concentrations of florfenicol and oxytetracycline for animal isolates of pasteurella multocida and salmonella typhimurium |
| topic | Cattle Salmonella typhimurium Pasteurella multocida Horses Mutant prevention concentration (mpc) Pigs Minimum inhibitory concentration (mic) UCTD |
| url | http://hdl.handle.net/2263/26219 http://upetd.up.ac.za/thesis/available/etd-07112013-131057/ |