2001 Fiscal Year Final Research Report Summary
The Mechanism of Antibiotic-tolerance in Adherent bacteria
| Project/Area Number |
12671774
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Morphological basic dentistry
|
|---|
| Research Institution | The University of Tokushima |
|---|
Principal Investigator |
ONO Tsuneko School of Medicine, The University of Tokushima, Professor, 歯学部, 教授 (40035514)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
NEMOTO Ken The University of Tokushima, School of Dentistry, Research Associate, 歯学部, 助手 (10218274)
HIROTA Katsuhiko The University of Tokushima, School of Dentistry, Professor, 歯学部, 助手 (60199130)
MIYAKE Yoichiro School of Dentistry, The University of Tokushima, Professor, 歯学部, 教授 (80136093)
|
|---|
| Project Period (FY) |
2000 – 2001
|
| Keywords | Pseudomonas aeruginosa / adherence / antibiotics tolerance / tcp gene / bta gene / rpoS gene |
|---|
| Research Abstract |
In this project, we have studied about the mechanism of antibiotics tolerant in adherent cells of Pseudomonas aeruginosa. The following results were obtained in this study.
1. The effect of several types of stress on antibiotic tolerance and the involvement of rpoS gene. It was found that the stationary phase bacteria were more tolerant to antibiotics than log phase bacteria and the rpoS defective mutant was less tolerant than the wild type strain. In early stage after the addition of biapenem, heat shock stress and osmotic stress induced bacterial tolerance to antibiotics. RpoS gene may be involved in the antibiotic tolerance of P. aeruginosa.
2. Identification of the genes associating the mechanism of antibiotics tolerant in adherent cells. Transposon Tn1737KH insertion mutants were constructed. One of them, a strain KMX7803, exhibited high tolerance to biapenem, has been obtained. The MBC of biapenem to adherent cells was 8 times higher than that of the wild type. In planktonic cells, the survival of the mutant at 3 hours after the addition of biapenem was about 1000 times higher than that of the wild type.
A mutant KMX50, exhibited low tolerance to biapenem, has been obtained. The MIC and MBC of biapenem to strain KMX50 was exactly the same as that of the wild type. In planktonic cells, the survival of the mutant at 2 hours after the addition of biapenem was about 1000 times lower than that of the wild type.
In the strain KMX7803, Tn1737KH was inserted in the open reading frame called PA056, which was designated top. In the strain KMX50, the transposon was inserted in the open reading frame called PA2242, which was designated bta.
These mutants were useful tools to elucidate the tolerant mechanisms of adherent bacteria to antibiotics.
|
