[Effects of Pseudomonas quinolone signal on the virulence of Pseudomonas aeruginosa].
OBJECTIVE
To investigate the effect of Pseudomonas quinolone signal (PQS) on the virulence of Pseudomonas aeruginosa.


METHODS
Pseudomonas aeruginosa strain PAO1 was treated with PQS alone, PQS plus farnesol, or farnesol alone. The transcriptional levels of the regulator gene ExsA and virulence protein gene ExoS of type III secretion system were examined using quantitative real-time PCR, and spectrophotometry was employed to detect pyocyanin production in the bacteria. The adhesion and invasiveness of the treated PAO1 in cultured alveolar epithelial cells A549 were assessed on plate count agar, and their effects on the survival of a mouse model of peritonitis was compared.


RESULTS
The increase or decrease of PQS did not affect the growth of PAO1. Compared with the untreated bacteria, PQS-treated PAO1 showed obviously increased transcription levels of ExsA and ExoS (P<0.01) and pyocyanin production, which was significantly lowered by farnesol (P<0.01). In A549 cell cultures, farnesol-treated PAO1 exhibited significantly lowered adhesion and invasiveness, while PQS-treated PAO1 caused a significantly decreased survival time of mice with peritonitis (P<0.01). Farnesol treatment did not obviously affected ExsA transcription (P>0.05) but caused a significant reduction in the transcriptional level of Exos (P<0.05) in PAO1. PQS showed no significant effect on the adhesion and invasiveness of PAO1 (P<0.05).


CONCLUSIONS
PQS can maintain the adhesion and invasiveness of Pseudomonas aeruginosa, and in the hosts of the bacteria, PQS concentration is positively correlated with pyocyanin production and hence negatively with the survival time of the hosts.
Chongqing International Science and Technology Cooperation, Chongqing, China. 904576693@qq.com
Xiaohong
X
Fu
Xuemei
X
Zhang
Chunmei
C
Jing
Lan
L
Liu
Yibing
Y
Yin
Junru
J
Jiang
D036002:ADP Ribose Transferases / Q000235:genetics / Q000378:metabolism; D000818:Animals; D001422:Bacterial Adhesion; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D001427:Bacterial Toxins / Q000235:genetics / Q000378:metabolism; D002460:Cell Line; D006801:Humans; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D010538:Peritonitis / Q000382:microbiology; D011550:Pseudomonas aeruginosa / Q000235:genetics / Q000378:metabolism* / Q000472:pathogenicity*; D015363:Quinolones / Q000494:pharmacology*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic; D014774:Virulence
C407944:2-heptyl-3-hydroxy-4-quinolone; D001426:Bacterial Proteins; D001427:Bacterial Toxins; C095093:ExsA protein, Pseudomonas aeruginosa; D015363:Quinolones; D011993:Recombinant Fusion Proteins; D015534:Trans-Activators; D036002:ADP Ribose Transferases; C444820:exoenzyme S