Alcaligenes xylosoxidans keratitis post penetrating keratoplasty in a rigid gas permeable lens wearer

We report a case of Alcaligenes xylosoxidans keratitis following penetrating keratoplasty in a rigid gas permeable (RGP) lens wearer. A 61 year old RGP lens wearer with a history of nonresponsive keratitis of the right eye which involved the graft margin was referred to us for treatment. Corneal cultures revealed growth of a gram-negative rod on the fifth day and the organism was subsequently identified as Alcaligenes xylosoxidans, which was resistant to most antibiotics and sensitive only to Bactrim, Timentin, and imipenem. Clinical improvement was observed within 24 hours after treatment with the use of topical i.v. Bactrim and topical i.v. Timentin 2% alternating every 30 minutes. Complete resolution of the infection with mild scarring was observed 6 weeks after treatment. Alcaligenes xylosoxidans is a potential cause of bacterial keratitis which should be considered in cases of nonresponsive gram-negative keratitis. The addition of topical Bactrim or Timentin may need to be considered in such cases.