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。研究纳入2012年8月至2022年4月期间，密歇根大学电子健康档案中留存角膜及CLR培养结果的MK患者。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，本研究采用线性回归分析视力的变化趋势，以及90天视力与基线视力的差值（即视力变化量）与角膜及CLR培养结果之间的关联；采用单样本t检验验证斜率估计值是否与0存在显著差异。本研究共纳入50例MK患者，患者平均年龄为49岁（标准差=20.9），女性占比56%，白人占比90%。其中60%的患者角膜培养结果呈阳性，64%的患者CLR培养结果呈阳性，38%的患者两项培养结果均为阳性。角膜培养与CLR培养结果的一致率为30%（n=15/50）。角膜及CLR培养结果均为阳性的患者，其LogMAR VA随时间显著改善（回归系数=-0.19/每10天，p=0.002）；角膜培养结果阴性但CLR培养结果阳性的患者同样出现视力改善（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培养结果均为阴性的患者相比，角膜及CLR培养结果均为阳性的患者（回归系数=-0.68，p=0.068）以及角膜培养结果阴性但CLR培养结果阳性的患者（回归系数=-0.74，p=0.059）的视力均呈现改善趋势。CLR培养结果阳性与患者视力随时间的显著改善存在关联。此类补充培养可为抗菌药物的合理选择提供参考，尤其在角膜培养结果为阴性时尤为重要。