The Role of Oxidative Stress Tolerance and Transformation Competence in the Acquisition of Antibiotic Resistance in Haemophilus ducreyi

Becker, Austin

The Role of Oxidative Stress Tolerance and Transformation Competence in the Acquisition of Antibiotic Resistance in Haemophilus ducreyi

Persistent URL

http://hdl.handle.net/10456/34307

Author(s)

Becker, Austin

Date Issued

April 26, 2013

Abstract

This study explored the source of beta-lactam resistance and contributing factors allowing acquisition of antibiotic resistance in Haemophilus ducreyi strain HD85-023233 (HD85). The antioxidant protein Cu,Zn superoxide dismutase (SOD) was analyzed because it may promote tolerance to neutrophil generated oxidative burst and oxidative induced damage from antibiotics. Tolerance to both these factors may have aided in the ability of the HD85 strain to persist for a long enough time to acquire antibiotic resistance genes. Expression of sodC mRNA was present and equal in HD85 and 35000HP (35K) during exponential phase suggesting a potential role of Cu,Zn superoxide dismutase in oxidative tolerance through constitutive expression. To understand the origin of antibiotic resistance in HD85, the antibiotic resistance genes of HD85 were studied, as well as its competence genes to assess transformation as a potential mechanism of antibiotic resistance acquisition. This study shows the resistance of strain HD85 is due to a plasmid carrying a TEM-1 beta-lactamase gene and that HD85 has premature stop codons in 3 competence genes. Thus, transformation was an unlikely contributor to the acquisition of plasmid DNA encoding resistance genes in HD85.

Honors

Biology, 2013

First Reader(s)

Kleinschmidt, Ann