Multidrug-Resistant Pseudomonas aeruginosa Keratitis: Risk Factors, Clinical Characteristics, and Outcomes

To identify risk factors for multidrug-resistant Pseudomonas aeruginosa (MDR-PA) keratitis and to report clinical characteristics and outcomes of this infection. Retrospective, case-control study. Ninety episodes of P. aeruginosa keratitis from a tertiary care eye institution from 2007 through 2014 were identified. Episodes of MDR-PA keratitis were taken as cases. Episodes of drug-sensitive P. aeruginosa keratitis during the same period were taken as controls. Chart review of cases and controls. Multidrug resistance was defined as resistance to 3 or more classes of antimicrobial drugs. Logistic regression analysis was used to determine association of baseline characteristics with multidrug resistance. Clinical characteristics and risk factors in each group also were compared. Risk factors for multidrug resistance, including age, gender, eye, duration of symptoms, topical steroid or lubricant ointment use, trauma, prior ocular surgery, presence of a compromised ocular surface, and bandage contact lens use. Twenty-three episodes of MDR-PA keratitis (cases) and 67 episodes of drug-sensitive P. aeruginosa keratitis (controls) were identified. In the multivariate analysis, lubricant ointment use, presence of a compromised ocular surface, and bandage contact lens use were associated with MDR-PA keratitis. Antimicrobial resistance in the MDR-PA keratitis isolates was least for colistin and imipenem (56.52% each). Corneal perforation was more common in cases (52.17% [12 of 23]) than in controls (11.94% [8 of 67]; P = 0.0001). Cyanoacrylate glue application was required in 47.82% of cases (11 of 23), compared with 22.38% of controls (15 of 67; P = 0.031). Keratoplasty was more commonly required in cases (47.82% [11 of 23]) than in controls (20.89% [14 of 67]; P = 0.017). Lubricant ointment use, a compromised ocular surface, and bandage contact lens use are associated with MDR-PA keratitis. Preservative-free lubricant ointment may act as a source or reservoir of infection. Outcomes are worse in MDR-PA keratitis compared with drug-sensitive P. aeruginosa keratitis.