Objective To observe and analyze the risk factors of positive conjunctival capsule microbial culture in patients with intravitreal injection (IVT) before treatment. MethodsA prospective study. A total of 1 092 patients who received IVT at the Vitreous Injection Center of Tianjin Medical University Eye Hospital from February 2021 to February 2024 were included in the study. Among them, 539 were males and 553 were females. The age was (62.29±13.61) years. Hypertension and diabetes were 661 and 576 cases, respectively. There were 742 cases of urban residence and 350 cases of rural residence. Three and one days before IVT, 364 patients received antibiotics and 364 patients did not receive antibiotics. Patients' gender, age, history of hypertension and diabetes, pre-IVT antibiotic eye drops use history, and differences in residence (town/country) were collected in detail. Samples were collected after the conjunctival sac was rinsed, and microbial culture was performed. The differences in conjunctival microbial culture positivity rates was compared between those who did not use antibiotic eye drops before IVT, those who used them 1 day before IVT, and those who used them 3 days before IVT. The positive rate of conjunctival sac microbial culture were compared among individuals of different ages, genders, with/without hypertension, with/without diabetes, with different IVT times, and from different living areas (urban/rural). The clinical baseline of positive conjunctival capsule bacterial culture was compared and observed. χ2 test was used to compare the positive rate of conjunctival capsule microbial culture among different clinical baselines. Logistic binary regression analysis was used to analyze the influencing factors. ResultsAmong the 1 092 patients, 54 cases (4.95%, 54/1 092) were positive for microbial culture of conjunctival sac. There was no significant difference (P＞0.05) in the positive rate of conjunctival sac microbial culture among patients of different ages (χ2=5.599), gender (χ2=0.549), residence (χ2=0.153), with or without hypertension and diabetes (χ2=3.545, 0.044), and with or without diabetic macular edema (χ2=0.180). There was no significant difference (P＞0.05) in the positive rate of conjunctival sac microbial culture between patients with different numbers of IVT (χ2=0.961) or between those who received antibiotic eye drops before IVT and those who did not (χ2=5.600). Logistic binary regression analysis showed that none of the above factors were risk factors for positive conjunctival capsule microbial culture (P＞0.05). No infective endophthalmitis occurred in all patients during the observation period. ConclusionThe use of antibiotics before IVT is not the decisive factor for positive microbial culture in conjunctival sac.
ObjectiveTo observe the differences in the positive rate of conjunctival sac microbial culture after different methods of preventing infection before intravitreal injection (IVI). MethodsA prospective case-control study. A total of 1 200 participants with fundus diseases who received IVI injection at Tianjin Medical University Eye Hospital from July 2021 to December 2023 were included. Patients were randomly divided into 6 groups according to eye spot with antibiotic solution 3, 1 and 0 days before IVI and local eye disinfection with povidone-iodine (PVI) 3 min and 30 s before IVI: the first 3 days of antibiotics+3 min PVI group, the first 1 day of antibiotics+3 min PVI group, the first 0 days of antibiotics+3 min PVI group, the first 3 days of antibiotics+30 s PVI group, the first 1 day of antibiotics+30 s PVI group, the first 0 days of antibiotics+30 s PVI group, there were 200 cases in each group. Microbial sampling and cultivation of conjunctival sac were conducted before IVI to compare the differences in positive rates among different groups. Multiple group comparisons were conducted using one-way analysis of variance. The comparison of count data is conducted using χ2 test. ResultsAmong the 1 200 patients, there were 566 males and 634 females. Age (62.59±13.44) years old. There were 397 cases of diabetes and 482 cases of hypertension. IVI frequency (2.35±2.34). 64 cases were positive for conjunctival sac culture before IVI. The age (F=1.468), sex composition ratio (χ2=2.876), diabetes (χ2=10.002), hypertension (χ2=6.019), times of IVI (χ2=4.507), and positive rate of conjunctival sac bacterial culture (χ2=6.272) of patients in each group had no statistical significance (P＞0.05). Using the duration of antibiotic application before IVI as a stratified factor, there was no statistically significant difference in the positive rate of conjunctival sac culture between groups with different durations of antibiotic application before IVI [χ2=0.414, P=0.52, combined odds ratio (OR)=0.819, 95% confidence interval (CI) 0.493-1.360]. Using the duration of PVI application as a stratified factor, there was no statistically significant difference in the positive rate of conjunctival sac culture between different PVI disinfection times [χ2=0.000, P=1.000, combined OR=1.00, 95%CI 0.503-1.988]. ConclusionsPre IVI treatment with 0.5% PVI for 30 s can inhibit the growth of microbial colonies in the conjunctival sac. The application of local antibiotic eye fluid in the anterior eye of IVI cannot reduce the positive rate of conjunctival sac bacteria.