Posters

Multi-drug resistant pseudomonas keratitis and its successful treatment with 1.5% colistimethate sodium

Poster Details

First Author: S.Chatterjee INDIA

Co Author(s):    D. Agrawal              

Abstract Details

Purpose:

Increasing reports of antibiotic resistance worldwide in systemic and ocular bacterial infections is of serious concern. Bacterial keratitis due to Pseudomonas aeruginosa is severe and fulminant and would be more so if the isolate is resistant to multiple antibiotics. We present the clinical features and outcome of bacterial keratitis caused by multi-drug resistant [MDR] isolates of Pseudomonas aeruginosa and report the successful treatment with 1.5% Colistimethate sodium in 3 patients.

Setting:

Cornea & Anterior Segment Services, MGM Eye Institute, Raipur, India

Methods:

The medical records of 12 culture-proven MDR PA keratitis who presented between 2005 -2013 were retrospectively reviewed for demographic details, clinical features, ulcer progression and microbiology findings. Progression was measured by the doubling time of the infiltrate and the time interval to perforation. All patients had undergone standard microbiology work-up. Antibiotic susceptibility testing was done by the Kirby Bauer disc diffusion method as per the standards of Clinical and Laboratory Standards Institute. Multi-drug resistance was considered if the bacterial isolate exhibited resistant pattern to ≥ 3 class of antibiotics. 8 patients were treated with either 0.3% Ciprofloxacin or Ofloxacin while 3 patients were treated with 1.5% colistimethate sodium and 1 patient with 5% Imipenem/cilastin. 1.5% colistimethate sodium was prepared by reconstituting 75mg of Colistimethate sodium (Xylistin, Cipla) powder for injection with 5ml water for injection and Imipenem/cilastin 5% was prepared by reconstituting 10ml of water for injection to 50mg of Imipenem/cilastin (Cilaster, Alkem Ltd, India). All topical antibiotics were instilled half-hourly for first 48-72 hours and then 1 hourly during day time and 3 hourly during the night and reduced with clinical improvement.

Results:

Twelve patients (8 males, 4 females) with ages ranging from 6-64 years exhibited in vitro resistance to ciprofloxacin, ofloxacin, moxifloxacin, gatifloxacin, gentamycin, tobramycin, amikacin, ceftazidime and chloramphenicol. The ulcers were large (mean size: 55.75 ± 56.91 mm2 with total corneal involvement in 4 ) and rapidly progressive (mean duration: 3.58 ± 3.75 days). Of the 8 patients treated with Fluoroquinolones, 4 (50%) required evisceration, 1 (13%) became pthisis bulbi, 1 underwent therapeutic keratoplasty and 2 (25%) showed no improvement. One patient treated with 5% Imipenem/cilastin showed no improvement and underwent therapeutic keratoplasty. All 3 (100%) patients treated with 1.5% Colistimethate sodium healed.

Conclusions:

Clinical features of MDR Pseudomonas keratitis is one of severe ulceration, fulminant progression and poor outcome with medical treatment. In this small series 1.5% colistimethate sodium was effective in the treatment of MDR Pseudomonas keratitis. Routine antibiotic susceptibility testing in bacterial keratitis with Pseudomonas aeruginosa should include alternative non-conventional antibiotics like colistimethate sodium. FINANCIAL INTEREST: NONE