title: Extensively and pan-drug resistant Pseudomonas aeruginosa keratitis: clinical features, risk factors, and outcome.
abstract: BACKGROUND
  Emergence of multi-drug resistant (MDR), extensively drug resistant (XDR), and pan-drug resistant (PDR) strains of Pseudomonas aeruginosa pose a significant therapeutic challenge. Managing XDR and PDR Pseudomonas aeruginosa keratitis would be extremely difficult due to paucity of safe and effective topical medications. We aim to describe the clinical features, risk factors, and outcome of XDR and PDR Pseudomonas aeruginosa keratitis.
  
  
  METHODS
  A retrospective chart review of consecutive cases of XDR and PDR Pseudomonas aeruginosa keratitis were identified from Ocular Microbiology Department. XDR and PDR were defined based on criteria established by Centers for Disease Control and European Centre for Disease Prevention and Control. The following data was collected: age, gender, occupation, symptom duration, systemic and ocular risk factors, infiltrate characteristics, antimicrobial susceptibility, complications, surgical interventions, presenting, and final visual acuity and final outcome. Complete success was defined as resolution of the infiltrate with scar formation on medical treatment alone. Partial success was the resolution following tissue adhesive application. Failure was an inadequate response to medical therapy with progressive increase in infiltrate, corneal melting, and/or perforation necessitating one or more therapeutic penetrating keratoplasties or evisceration.
  
  
  RESULTS
  Fifteen eyes of 13 patients were included. Seven (53.8 %) were male with left eye involvement in nine (60 %) cases. Most common risk factors were bandage contact lens (6, 40 %), topical steroids (5, 33.3 %), previous therapeutic graft (4, 26.6 %), and ocular surface disorder (OSD) following Stevens Johnson Syndrome (SJS) (4, 26.6 %). Of 15 isolates, six (40 %) were sensitive only to imipenem, three (20 %) to colistin, two (13.3 %) to neomycin, one (6.7 %) each to imipenem and colistin, imipenem and ceftazidime, and azithromycin respectively. One isolate was resistant to all antibiotics. Complete success was noted in two (16.67 %), partial success in three (25 %) and failure in seven (58.33 %) eyes. Five (33.3 %) eyes healed on imipenem (three eyes), azithromycin (one eye), and imipenem and colistin (one eye).
  
  
  CONCLUSIONS
  XDR and PDR Pseudomonas aeruginosa keratitis are extremely difficult to treat. Globe salvage was possible in all cases; however, more than half required therapeutic grafts. Close monitoring of patients with known ocular and systemic factors is warranted.
authors.affiliation: Cornea and Anterior Segment Services, L. V. Prasad Eye Institute, Visakhapatnam, Andhra Pradesh, 530040, India. merle@lvpei.org.
authors.forename: Merle
authors.initials: M
authors.lastname: Fernandes
authors.affiliation: Cornea and Anterior Segment Services, L. V. Prasad Eye Institute, Visakhapatnam, Andhra Pradesh, 530040, India.
authors.forename: Divya
authors.initials: D
authors.lastname: Vira
authors.affiliation: Cornea and Anterior Segment Services, L. V. Prasad Eye Institute, Visakhapatnam, Andhra Pradesh, 530040, India.
authors.forename: Radhika
authors.initials: R
authors.lastname: Medikonda
authors.affiliation: Ocular Microbiology Department, L. V. Prasad Eye Institute, Visakhapatnam, Andhra Pradesh, 530040, India.
authors.forename: Nagendra
authors.initials: N
authors.lastname: Kumar
mesh_terms: D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D002939:Ciprofloxacin / Q000627:therapeutic use; D003091:Colistin / Q000627:therapeutic use; D003320:Corneal Ulcer / Q000175:diagnosis* / Q000382:microbiology / Q000628:therapy; D024901:Drug Resistance, Multiple, Bacterial; D015818:Eye Infections, Bacterial / Q000175:diagnosis* / Q000382:microbiology / Q000628:therapy; D005260:Female; D006801:Humans; D015378:Imipenem / Q000627:therapeutic use; D015948:Keratoplasty, Penetrating; D008297:Male; D008826:Microbial Sensitivity Tests; D015242:Ofloxacin / Q000627:therapeutic use; D011552:Pseudomonas Infections / Q000175:diagnosis* / Q000382:microbiology / Q000628:therapy; D011550:Pseudomonas aeruginosa / Q000187:drug effects / Q000302:isolation & purification*; D012189:Retrospective Studies; D012307:Risk Factors; D014792:Visual Acuity
chemical_list: D000900:Anti-Bacterial Agents; D002939:Ciprofloxacin; D015378:Imipenem; D015242:Ofloxacin; D003091:Colistin
keywords: Extensive drug resistance; Microbial keratitis; Multi-drug resistance; Pan-drug resistance; Pseudomonas aeruginosa