A Comparison of Culture Results and Visual Acuity in Contact Lens Related Microbial Keratitis

Evaluate the effect of corneal and contact lens-related (CLR) culture results on visual acuity (VA) in patients with microbial keratitis (MK). MK patients with corneal and CLR cultures were identified in the University of Michigan electronic health record from August 2012 to April 2022. Test results were classified as laboratory-positive or laboratory-negative. Linear regression was used to examine trends of VA and associations between changes in VA (differences of VA at 90-day and baseline VA) and corneal and CLR culture results, after adjustment for baseline VA. One-sample t-tests were used to test if the slope estimates were different from zero. MK patients (<i>n</i> = 50) were on average 49 years old (standard deviation = 20.9), 56% female, and 90% White. Positive corneal and CLR cultures were reported in 60% and 64% of patients, respectively, and 38% reported both. The agreement rate between corneal and CLR culture results was 30% (<i>n</i> = 15/50). LogMAR VA improved over time in patients with positive corneal and CLR cultures (Estimate=-0.19 per 10-day increase, <i>p</i> = 0.002), and in those with negative corneal and positive CLR cultures (Estimate= −0.17 per 10-day increase, <i>p</i> = 0.004). Compared to patients with negative corneal and CLR cultures, there was a trend toward improvement in VA for patients with positive corneal and CLR cultures (Estimate=-0.68, <i>p</i> = 0.068), and those with negative corneal and positive CLR cultures (Estimate= −0.74, <i>p</i> = 0.059), after adjusting for baseline VA. Positive CLR cultures are associated with significant improvement in VA over time. These additional cultures can provide guidance on appropriate antimicrobial selection, especially when corneal cultures are negative.

本研究旨在评估角膜及接触镜相关（contact lens-related, CLR）培养结果对微生物性角膜炎（microbial keratitis, MK）患者视力（visual acuity, VA）的影响。研究于2012年8月至2022年4月期间，在密歇根大学电子健康档案（electronic health record）中筛选出同时接受角膜培养及CLR培养的MK患者。将检测结果分为实验室阳性与实验室阴性两类。在校正基线视力后，采用线性回归分析视力变化趋势，以及视力变化（即90天随访视力与基线视力的差值）与角膜及CLR培养结果之间的关联；采用单样本t检验检验斜率估计值与0是否存在显著差异。本研究纳入的MK患者共50例（n=50），平均年龄49岁（标准差=20.9），其中女性占56%，白人占90%。分别有60%及64%的患者检出角膜培养阳性与CLR培养阳性，同时两项培养均为阳性的患者占38%。角膜培养与CLR培养结果的一致性率为30%（n=15/50）。角膜及CLR培养均为阳性的患者，其LogMAR视力随时间显著改善（回归系数=-0.19/每10天，p=0.002）；角膜培养阴性但CLR培养阳性的患者同样呈现视力改善趋势（回归系数=-0.17/每10天，p=0.004）。在校正基线视力后，与角膜及CLR培养均为阴性的患者相比，角膜及CLR培养均为阳性的患者（回归系数=-0.68，p=0.068）、角膜培养阴性但CLR培养阳性的患者（回归系数=-0.74，p=0.059）的视力均呈现改善趋势。研究结果显示，阳性CLR培养结果与患者视力随时间的显著改善相关。此类额外培养可为抗菌药物的合理选择提供指导，尤其在角膜培养结果为阴性时尤为重要。