title: Microbial analyses of contact lens-associated microbial keratitis.
abstract: OBJECTIVE
  To investigate the utility of additional microbial analyses to detect the causative microorganism of microbial keratitis and to determine the strength of association between clinical variables.
  
  
  METHODS
  This retrospective study included 125 eyes of 123 people presenting with presumed infectious keratitis associated with contact lens wear, and examined between January 2001 and November 2011.
  
  
  RESULTS
  Sixty-three male and 60 female patients with a mean age of 24.14 ( ±6.7) and 26.7 (±10.0) years, respectively, were included in the study. Among the samples tested, 38 (40%) corneal cultures, 85 (92%) contact lens cultures, and 49 (80%) contact lens case cultures yielded positive results. In the samples for which all microbial investigations were performed and corneal culture was positive, cultures of contact lenses and corneas yielded the same microbes in 94% of cases, and for contact lens case and corneal cultures 77% of cases yielded the same microbes. Importantly, these were monocultures of the same microbe isolated from the cornea in the contact lens and lens case cultures. The odds of having a positive corneal culture was 37 times higher (p = 0.008) when patients presented to the clinic 2 weeks after the onset of symptoms. Pseudomonas aeruginosa was the predominant organism isolated, and most isolates were susceptible to commonly used antimicrobials.
  
  
  CONCLUSIONS
  Contact lens culture might be an effective test to perform to detect and determine the causative microorganism when corneal cultures are unavailable or yield no microorganisms upon culture. A longer duration of symptoms before presenting to the clinic was significantly associated with obtaining a positive corneal culture.
authors.affiliation: *BOptom †MD ‡MS §MBA ∥PhD, FAAO Brien Holden Vision Institute (NK), Sydney, New South Wales, Australia; School of Optometry and Vision Science (NK, MDPW), University of New South Wales, Sydney, New South Wales, Australia; Jhaveri Microbiology Centre (SRM), Prof. Brien Holden Eye Research Centre, Hyderabad Eye Research Foundation, L. V. Prasad Eye Institute, Hyderabad, Andhra Pradesh, India; Cornea Service (PG), L. V. Prasad Eye Institute, Hyderabad, Andhra Pradesh, India; Ocular Microbiology Services (SS), L. V. Prasad Eye Institute, Bhubaneswar, Odisha, India; and Department of Biostatistics (MHA), L. V. Prasad Eye Institute, Hyderabad, Andhra Pradesh, India.
authors.forename: Nagaraju
authors.initials: N
authors.lastname: Konda
authors.forename: Swapna Reddy
authors.initials: SR
authors.lastname: Motukupally
authors.forename: Prashant
authors.initials: P
authors.lastname: Garg
authors.forename: Savitri
authors.initials: S
authors.lastname: Sharma
authors.forename: Mohd Hasnat
authors.initials: MH
authors.lastname: Ali
authors.forename: Mark D P
authors.initials: MD
authors.lastname: Willcox
mesh_terms: D000328:Adult; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D001419:Bacteria / Q000302:isolation & purification; D002437:Cefazolin / Q000627:therapeutic use; D002939:Ciprofloxacin / Q000627:therapeutic use; D003261:Contact Lenses / Q000382:microbiology*; D003320:Corneal Ulcer / Q000175:diagnosis / Q000188:drug therapy / Q000382:microbiology*; D004359:Drug Therapy, Combination; D004866:Equipment Contamination; D015818:Eye Infections, Bacterial / Q000175:diagnosis / Q000188:drug therapy / Q000382:microbiology*; D005260:Female; D005839:Gentamicins / Q000627:therapeutic use; D006801:Humans; D008297:Male; D012189:Retrospective Studies; D012307:Risk Factors; D055815:Young Adult
chemical_list: D000900:Anti-Bacterial Agents; D005839:Gentamicins; D002939:Ciprofloxacin; D002437:Cefazolin