Details

Autor(en) / Beteiligte

• Tamou, Christopher

Titel

Synergistic Effects of Meropenem and Conventional Antibiotics on Biofilms Formed by Klebsiella pneumoniae

Ort / Verlag

ProQuest Dissertations Publishing

Erscheinungsjahr

2021

Link zum Volltext

• ProQuest

Quelle

ProQuest Dissertations & Theses A&I

Beschreibungen/Notizen

• Antibiotic resistance in bacteria is becoming a widespread issue in the clinical and public health realms. Of major concern is the bacterium Klebsiella pneumoniae, which is notable due to its rapid spread. In 2017, there were an estimated 197,000 Klebsiella pneumoniae cases in the United States, with 9,100 deaths caused by these resistant and pathogenic bacteria. Current antibiotics are losing their effectiveness, leading to more frequent use of much stronger ones, including carbapenems. Carbapenems are potent antibiotics and primarily used as a last resort option in treating antibiotic resistant infections. Unfortunately, carbapenem resistance has been developing in bacteria as well. Resistance is further exacerbated by the development of structures called biofilms, which are communities of bacteria embedded in a polysaccharide and protein matrix that are difficult for antibiotics to penetrate. However, recent studies have shown that combining antibiotics and administering them to biofilms may have a synergistic effect in clearing the biofilms. The focus of this study is to pair conventional antibiotics with meropenem, a carbapenem, to determine whether any of the combinatorial treatments exhibit a synergistic effect on mitigating bacterial biofilms formed by an antibiotic resistant strain of Klebsiella pneumoniae. Minimum inhibitory concentration (MIC) assays were used to gauge which antibiotics, individually and combined, show a potential synergistic effect in reducing planktonic cell viability. Minimum biofilm inhibitory concentrations (MBIC) were determined to distinguish antibiotic synergy in reducing biofilm viability using the crystal violet assay. Finally, Klebsiella pneumoniae was plated and exposed to two optimal antibiotic combinations in Kirby-Bauer assays to determine whether combination therapy can delay the progressive evolution of antibiotic resistance. It was found that planktonic cells responded in several ways to the combined antibiotic pairs, including synergistically. However when administered to the biofilms, there was no synergy discovered among the antibiotic pairs; rather, antagonistic behavior was observed. The Kirby-Bauer analysis pointed out a difference in the zones of inhibition when meropenem was administered with an antibiotic compared to its individual use, suggesting that meropenem can influence the efficacy of the combined treatment and affect the regrowth of the bacterium. Observations collected from this study can be used to assess current treatment methods of biofilms in a clinical setting.