| Summary: | 碩士 === 義守大學 === 生物技術與化學工程研究所碩士班 === 98 === The widespread use of antibiotics has given rise to the development of resistant strains; this causes a major issue of worldwide attentation. An increase in the bacterial resistance was proposed due to the misuse and overuse of antibiotics and the resistant genes were found globally in the plasmids of many different kinds of bacteria. The aim of this research was to investigate the antibiotic properties of clinical pathogens, included Staphylococcus aureus, Pseudomonas aeruginosa, and Acinetobacter baumannii, which are responsible for numerous serious nosocomial infections.
In this study, the clinical strains were categorized into different phenotypes using antibiotic susceptibility test and the relationship between their antibiotic resistance and genotypes were determined by the molecular biotechnology methods, included plasmid transformation, PCR (polymerase chain reaction), SNPs (single nucleotide polymorphisms), and RFLP (restriction fragment length polymorphism).
A mount of 872 clinical isolates, included 378 strains of Staphylococcus aureus, 239 strains of Methicillin-resistant Staphylococcus aureus, 153 strains of Pseudomonas aeruginosa, and 102 strains of Acinetobacter baumannii, which were collected from 2005 to 2009, were used as the test strains in this study. Firstly, Ampicillin-resistant strains were selecte, randomly to perform the plasmid isolation and transformation. It was found that up to 87% of the clinical strains harbored plasmids and was able to develop antibiotic resistant. The transforms were then subjected to the antibiotic susceptibility test, the results revealed that more than 90% of the transformed plasmids were multi-drug resistant.
In the PCR analysis, 34% of the test strains were found to contain the blaOXA gene and 50% were found to possess the blaampC gene. All of the strains tested were found to have the blaTEM gene. The findings of the PCR analysis obtained from the strains of Acinetobacter baumannii indicated that if a strain contained the blaampC gene, it would also possess the blaOXA and blaTEM genes.
The SNPs analysis of the blaTEM gene and using the restriction enzyme to digest the PCR products could be used to identify a strain with streptomycin resistant or tetracycline resistant.
The results of this study can provide the useful academic information on the relevant to antibiotic resistance and the resistant genes that reside in plasmids. In addition, an effective method was proposed to identify streptomycin or tetracycline-resistant strains for medical diagnosis. The results obtained from this study can serve as a valuable reference for the future control on clinical resistant strains and more thorough discussions on resistance mechanisms.
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