Microbial Findings in Suture Erosion after Penetrating Keratoplasty

Abstract

The purpose of the study was to evaluate the presence of microorganisms in eroded (broken or loose) sutures post-penetrating keratoplasty (PKP). Fifty-five consecutive episodes of eroded 10-0 nylon sutures post-PKP in 35 eyes were evaluated. Eroded sutures were removed and, along with a swab from the conjunctiva, studied for aerobic and anaerobic bacteria. Preoperative diagnosis, elapsed time since surgery, presence of symptoms, suture location, infiltration, vascularization, and mucous at the suture site were recorded. Student's t test was used for statistical analysis. The average time from PKP to suture removal was 31.6 months. Eyes treated with topical steroids presented earlier suture erosions (P = 0.05). Of the 55 sutures, 34 were sterile, and in 21, both Staphylococcus epidermidis and diphtheroids (mixed flora) were cultured. Of the 55 conjunctivas, 32 were sterile, 22 showed mixed flora, and 1 had Pseudomonas. Sutures eroded for more than 24 hours had more positive cultures than those eroded for 24 hours or less (P = 0.043). Sutures located superiorly had fewer positive cultures than did those in the palpebral fissure area (P = 0.044). Eyes with repeated suture erosions had more culture-positive sutures (P = 0.017) and conjuctivas (P = 0.014) at the first erosion in comparison with the second erosion. Infiltration, vascularization, or muscus at the suture site did not correlate with positive cultures. Bacteria are encountered at the site of eroded sutures. Patients with PKP should report symptoms immediately, and eroded sutures should be removed as early as possible.