Objective: To investigate the pathogen species, composition, and distribution characteristics of infectious keratitis pathogens in Shandong Province and its surrounding areas. Methods: In this cross-sectional study, patients with keratitis who underwent corneal sampling and microbiological culture at the Shandong Eye Hospital from January 1, 2018 to December 31, 2022 were included. Under topical anesthesia, the edge of the lesion was scraped by an experienced physician. The samples were inoculated on blood agar and Sabouraud dextrose agar plates, separately for bacterial and fungal culture and identification. If necessary, the samples were inoculated on a non-nutrient agar medium with Escherichia coli for Acanthamoeba culture. Bacterial isolates were identified using Vitek 2 compact or matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Fungal isolates were identified based on morphological characteristics or sent to a company for sequencing in cases of difficult identification. The epidemiological data of the patients, pathogen species and number (counting as 1 strain if the same strain was isolated from multiple corneal specimens of the same patient), culture positivity rate, and seasonal distribution were recorded. Differences in pathogen positivity rates among different seasons were analyzed using the chi-square test. Results: Among the 4, 024 patients with infectious keratitis during the study period, there were 2 510 males (62.3%) and 1 514 females (37.6%), aged from 46 days to 94 years. Positive microbial culture results were achieved in 2, 363 patients (58.7%), including 906 cases (38.3%) with bacterial positivity, 1 231 cases (52.1%) with fungal positivity, 28 cases (1.2%) with Acanthamoeba positivity, and 198 cases (8.4%) with mixed fungal and bacterial infections. A total of 2 561 strains were isolated, including 1 104 bacterial strains. The most common bacteria were coagulase-negative Staphylococcus spp. (623/1 104, 56.4%), followed by Streptococcus spp. (131/1 104, 11.9%) and Pseudomonas aeruginosa (68/1 104, 6.2%). The most common fungi were Fusarium spp. (634/1 429, 44.4%), followed by Aspergillus spp. (279/1 429, 19.5%) and Alternaria spp. (229/1 429, 16.0%). Bacterial keratitis was more common in summer and autumn, while fungal keratitis was more common in autumn and winter. Conclusions: Among infectious keratitis cases in Shandong Eye Hospital, Fusarium species were predominant fungal pathogens, while coagulase-negative Staphylococcus predominated in bacterial pathogens. Both fungal and bacterial corneal infections showed seasonal variations.
目的： 探讨山东省及其周边地区感染性角膜炎的病原体种类、构成及分布特征。 方法： 横断面研究。收集2018年1月1日至2022年12月31日在山东省眼科医院进行角膜取材和微生物培养的角膜炎患者。刮取所有患者的角膜病灶组织，分别进行细菌和真菌培养，必要情况下行棘阿米巴培养。细菌培养阳性者采用全自动微生物系统或基质辅助激光解吸电离飞行时间质谱进行鉴定；真菌培养阳性者依据形态学进行真菌种属鉴定，鉴定困难的菌株外送测序公司进行测序。收集患者的人口学资料及病原体的种类和数量，获得培养阳性率，并根据患者就诊时间观察病原体的季节分布。 结果： 共收集到感染性角膜炎患者4 024例，其中男性2 510例（62.3%），女性1 514例（37.6%），年龄46 d至94岁。病原体培养结果为阳性的患者2 363例（58.7%），其中单纯细菌感染906例（38.3%），单纯真菌感染1 231例（52.1%），棘阿米巴阳性28例（1.2%），真菌和细菌混合感染198例（8.4%）。共分离得到病原体2 561株，其中细菌1 104株，真菌1 429株，棘阿米巴28株。常见细菌依次为凝固酶阴性的葡萄球菌（623株，占56.4%）、链球菌属（131株，占11.9%）、铜绿假单胞菌（68株，占6.2%）等；常见真菌依次为镰刀菌属（634株，占44.4%），其次是曲霉菌属（279株，占19.5%）、链格孢霉属（229株，占16.0%）等。细菌性角膜炎多发于夏、秋季，而真菌性角膜炎多发于秋、冬季。 结论： 山东省眼科医院收治的感染性角膜炎中，真菌感染以镰刀菌为主，细菌感染以凝固酶阴性的葡萄球菌为主，两者的分布均存在季节性差异。.