Abstract
Purpose :
Infectious keratitis is the most concerning complication after corneal surgeries including corneal crosslinking (CXL) for keratoconus. We started CXL for progressive keratoconus in 2009 and had never experienced postoperative infectious keratitis until 2015. However, sporadic cases were noted from 2016 onward. We also found that all of the causal bacteria were resistant to levofloxacin (Kato et al, BMC Ophthalmol 2021). For the prevention of postoperative infectious keratitis, we recently began to preoperatively screen for microbes via nasal culture, because the conjunctival sac is seldom culture-positive when patients do not develop conjunctivitis. In the present study, we summarize the outcomes of the nasal cultures, the types of bacteria, and drug sensitivity.
Methods :
Preoperative swab cultures from the nasal vestibule of 97 consecutive patients (22.5 ± 6.5 years-old, 80 males and 17 females) with progressive keratoconus were taken. The detected bacteria and drug sensitivity were summarized.
Results :
One to four types of bacteria were detected in 96 cases (99%). Among gram-positive cocci (GPC), 33% were resistant to penicillin antibiotics, 15％ to Cephem type, 32% to erythromycin, and 12% to levofloxacin (LVFX). Among LVFX-resistant GPC, 70% were also resistant to penicillin, 50% to cephem, 50% to erythromycin, and 20% to gentamicin, but 30% of them were resistant only to LVFX. In contract, 99% of the GPC were sensitive to chloramphenicol. Gram-negative rods were detected in 16 cases, and all of them were sensitive to LVFX. Gram-positive rods were detected in 42 cases. Among gram-positive rods, only one (2%) showed to be resistant to LVFX.
Conclusions :
We should be aware to that the prescription of LVFX alone is not enough to prevent post-CXL infection in the recent environment. A nasal swab culture may be helpful to predict the tendency of drug sensitivity/resistance of the resident bacteria and to choose postoperative antibiotics.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.