Rodriguez A F, Kaplan S L, Hawkins E P, Mason E O
Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030.
J Infect Dis. 1991 Dec;164(6):1207-9. doi: 10.1093/infdis/164.6.1207.
Sensorineural deafness occurs in 20%-30% of children after Streptococcus pneumoniae meningitis. An infant rat model of S. pneumoniae meningitis was developed to study the pathogenesis of inner ear invasion by S. pneumoniae. S. pneumoniae type 6 was administered intraperitoneally (inoculum: 1-10 x 10(8) cfu) every 24 h for 3 days to 5-day-old rats. Bacteremia (12 [50%] of 24) and meningitis (11 [46%] of 24) were detected most frequently 4 days after the three doses. The mean cerebrospinal fluid (CSF) white blood count for rats with positive CSF cultures was 7271/mm3 (range, 81-20,475). Hematoxylin-eosin-stained brain tissue from the 11 rats with positive CSF cultures showed inflammation in the meninges and scala tympani in 9 each (82%), and scala vestibuli in 6 (55%), but none in the scala media. Gram's-stained brain and inner ear sections from the same 11 rats showed organisms in the meninges in 5 (45%) and scala tympani or vestibuli in 2 (18%). Perilymphatic inflammation occurred significantly (P less than .001) more than did endolymphatic inflammation.
20%-30%的儿童在感染肺炎链球菌性脑膜炎后会出现感音神经性耳聋。为了研究肺炎链球菌侵袭内耳的发病机制，建立了婴儿大鼠肺炎链球菌性脑膜炎模型。对5日龄大鼠每隔24小时腹腔注射6型肺炎链球菌（接种量：1-10×10⁸cfu），共注射3天。在注射三剂后的第4天，最常检测到菌血症（24只中有12只[50%]）和脑膜炎（24只中有11只[46%]）。脑脊液培养呈阳性的大鼠脑脊液白细胞平均计数为7271/mm³（范围为81-20475）。对11只脑脊液培养呈阳性的大鼠进行苏木精-伊红染色的脑组织检查，结果显示9只（82%）的脑膜和鼓阶有炎症，6只（55%）的前庭阶有炎症，但中阶无炎症。对同11只大鼠的脑和内耳切片进行革兰氏染色，结果显示5只（45%）的脑膜中有细菌，2只（18%）的鼓阶或前庭阶中有细菌。外淋巴炎症的发生明显（P<0.001）多于内淋巴炎症。
