2006 Fiscal Year Final Research Report Summary
Interrelationship of efflux, invasion, and quorum sensing
| Project/Area Number |
16390132
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Bacteriology (including Mycology)
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| Research Institution | Nagasaki University |
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Principal Investigator |
HIRAKATA Yoichi Nagasaki University, Hospital of Medicine and Dentistry, lecture, 医学部・歯学部附属病院, 講師 (50238341)
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| Project Period (FY) |
2004 – 2006
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| Keywords | Pseudomonas aeruginosa / efflux system / invasion / efflux pomp inhibitor (EPI) |
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| Research Abstract |
We studied the quorum sensing (QS) system and the related homoserine lactones (HSLs) observing Peudomonas aeruginosa invasion using the epithelial cell monolayer penetration assay model. Compared to the PAO1 wild-type, the QS mutants, ΔlasI and ΔrhlI, were compromised in its capacity to invade. The decreased invasiveness of Δ rhlI was restored by adding 100 μM exogenous C_4-HSL. However, the decreased invasiveness of an efflux mutant, ΔmexAB-oprM, was not restored in the presence of exogenous HSLs. The QS system partially plays a role in P. aeruginosa invasion ; however, C_4-HSL and 3-O-C_<12>-HSL are not the essential determinants for invasiveness for P. aeruginosa. The invasiveness of PAO1 WT was reduced in the presence of the efflux inhibitors (EPIs), MC-207,110 or D13-9001. In the presence of 1 μg/ml of EPIs, the invasiveness of PAO1 WT was slightly suppressed (not significant, P=0.69). On the other hand, in the presence of 10-100 μg/ml of EPIs, the invasiveness of PAO1 WT was significantly reduced in the concentration-dependent manner (P<0.01). The findings support that invasion determinant(s) are predominantly exported by P. aeruginosa via MexAB-OprM, and that the EPIs are useful to reduce not only antimicrobial resistance but also the invasiveness of P. aeruginosa.
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