金黄色葡萄球菌菌株对结膜的不同毒力。

Diverse virulence of Staphylococcus aureus strains for the conjunctiva.

机构信息

Department of Microbiology, University of Mississippi Medical Center, 2500 N. State St., Jackson, MS 39216, USA.

出版信息

Curr Eye Res. 2011 Jan;36(1):14-20. doi: 10.3109/02713683.2010.523194.

DOI:10.3109/02713683.2010.523194

PMID:21174593

Abstract

PURPOSE

To determine the virulence of Staphylococcus aureus strains in the rabbit conjunctiva.

METHODS

Three strains of methicillin-sensitive S. aureus (8325-4, Newman, and UMCR1) and two strains of methicillin-resistant S. aureus (70490 and MW2) were analyzed. Rabbit bulbar conjunctivas (n ≥ 6 per group) were injected with 10(5) colony forming units (CFU) in 10 µl. Eyes were photographed and analyzed for pathology at 20 hr postinfection (PI) using slit lamp examination (SLE) to measure five parameters on a scale from 0 (normal) to 4 (severe): injection, chemosis, iritis, corneal edema, and pinpoint conjunctival hemorrhages. The parameter grades were added to produce a SLE score. Bacteria were enumerated and histopathological analysis was done at 20 hr PI. Myeloperoxidase assays were performed on conjunctival swabs (n ≥ 3 per strain) at 0 and 20 hr PI.

RESULTS

Conjunctivas injected with 8325-4 or Newman had SLE scores of 1.67 ± 0.12 and 0.81 ± 0.16, respectively. Strain 70490 produced an average SLE score of 2.94 ± 0.47, whereas MW2 produced a score of 5.04 ± 0.73. UMCR1 produced severe conjunctivitis having a SLE score of 13.25 ± 0.80. Only strain UMCR1 grew in the conjunctiva showing a 2.7 log increase in CFU; all other strains remained near the inoculated numbers or decreased as much as 1.85 logs. Myeloperoxidase activity was greatest in the tear film of UMCR1 infected eyes with over one million PMN present at 20 hr PI.

CONCLUSIONS

Only one S. aureus strain, UMCR1, was able to cause a reproducible severe conjunctivitis. This conjunctival infection could be used to test new antimicrobials and to help understand the pathogenesis of conjunctivitis, especially in terms of overcoming the host defenses.

摘要

目的

确定金黄色葡萄球菌菌株在兔结膜中的毒力。

方法

分析了 3 株甲氧西林敏感金黄色葡萄球菌（8325-4、Newman 和 UMCR1）和 2 株甲氧西林耐药金黄色葡萄球菌（70490 和 MW2）。用 10 µl 体积中的 10（5）个菌落形成单位（CFU）注射到兔球结膜（每组 n ≥ 6）。在感染后 20 小时（PI），通过裂隙灯检查（SLE）对眼睛进行拍照和病理分析，以 0（正常）至 4（严重）的等级测量 5 个参数：注射、球结膜水肿、虹膜炎、角膜水肿和针尖状结膜出血。将参数等级相加得出 SLE 评分。在 20 小时 PI 时对细菌进行计数并进行组织病理学分析。在 0 和 20 小时 PI 时，对结膜拭子（每个菌株 n ≥ 3）进行髓过氧化物酶测定。

结果

注射 8325-4 或 Newman 的结膜的 SLE 评分为 1.67±0.12 和 0.81±0.16。菌株 70490 产生的平均 SLE 评分为 2.94±0.47，而 MW2 产生的评分为 5.04±0.73。UMCR1 产生严重结膜炎，SLE 评分为 13.25±0.80。只有菌株 UMCR1 在结膜中生长，CFU 增加了 2.7 个对数；所有其他菌株均接近接种数量或减少 1.85 个对数。在感染 UMCR1 的眼睛的泪膜中，髓过氧化物酶活性最大，在 20 小时 PI 时有超过 100 万个 PMN 存在。