Fleiszig S M, Zaidi T S, Pier G B
Channing Laboratory, Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA.
Infect Immun. 1995 Oct;63(10):4072-7. doi: 10.1128/iai.63.10.4072-4077.1995.
Pseudomonas aeruginosa is usually considered an extracellular pathogen. Using assays to determine intracellular survival in the presence of gentamicin, we have previously demonstrated that P. aeruginosa is able to invade corneal cells during infectious keratitis in mice. In vitro, P. aeruginosa was found to enter the following cells: human corneal cells removed by irrigation; epithelial cells in the cornea of rats, mice, and rabbits; and primary corneal epithelial cells cultured from rat and rabbit eyes. The level of invasion was related to the level of adherent or associated bacteria. In general, invasion was more efficient with cultured epithelial cells than with cells tested in situ. Invasion did not occur when assays were performed at 4 degrees C. Cytochalasin D but not colchicine inhibited bacterial invasion, suggesting that bacterial entry was an endocytic process dependent on actin microfilaments but not microtubules. Bacteria that invaded cultured corneal epithelial cells were found to multiply within cells. The ability of P. aeruginosa to invade and multiply within corneal epithelial cells may contribute to the virulence of this organism during infectious keratitis, since intracellular bacteria can evade host immune effectors and antibiotics commonly used to treat infection.
铜绿假单胞菌通常被认为是一种胞外病原体。我们之前通过在庆大霉素存在的情况下测定细胞内存活率的试验，证明了铜绿假单胞菌在小鼠感染性角膜炎期间能够侵入角膜细胞。在体外，发现铜绿假单胞菌能进入以下细胞：通过冲洗去除的人角膜细胞；大鼠、小鼠和兔子角膜中的上皮细胞；以及从大鼠和兔子眼睛培养的原代角膜上皮细胞。侵袭水平与粘附或相关细菌的水平有关。一般来说，与原位测试的细胞相比，培养的上皮细胞的侵袭效率更高。在4℃进行试验时未发生侵袭。细胞松弛素D而非秋水仙碱抑制细菌侵袭，这表明细菌进入是一个依赖于肌动蛋白微丝而非微管的内吞过程。发现侵入培养的角膜上皮细胞的细菌在细胞内繁殖。铜绿假单胞菌在角膜上皮细胞内侵袭和繁殖的能力可能有助于该生物体在感染性角膜炎期间的毒力，因为细胞内细菌可以逃避宿主免疫效应物和常用于治疗感染的抗生素。
