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12-year analysis of incidence, microbiological profiles and in vitro antimicrobial susceptibility of infectious keratitis: the Nottingham Infectious Keratitis Study
  1. Darren Shu Jeng Ting1,
  2. Charlotte Shan Ho2,
  3. Jessica Cairns2,
  4. Ahmad Elsahn1,
  5. Mouhamed Al-Aqaba1,
  6. Tim Boswell3,
  7. Dalia G Said1,4,
  8. Harminder Singh Dua5
  1. 1 Academic Ophthalmology, University of Nottingham, Nottingham, UK
  2. 2 School of Medicine, University of Nottingham, Nottingham, UK
  3. 3 Department of Microbiology, Nottingham University Hospitals NHS Trust, Nottingham, UK
  4. 4 Ophthalmology, Nottingham University Hospitals NHS Trust, Nottingham, UK
  5. 5 Division of Ophthalmology and Visual Sciences, University of Nottingham, Nottingham, UK
  1. Correspondence to Professor Harminder Singh Dua, Division of Ophthalmology and Visual Sciences, University of Nottingham, Nottingham NG7 2U, UK; harminder.dua{at}


Background/aims To examine the incidence, causative microorganisms and in vitro antimicrobial susceptibility and resistance profiles of infectious keratitis (IK) in Nottingham, UK.

Methods A retrospective study of all patients who were diagnosed with IK and underwent corneal scraping between July 2007 and October 2019 (a 12-year period) at a UK tertiary referral centre. Relevant data, including demographic factors, microbiological profiles and in vitro antibiotic susceptibility of IK, were analysed.

Results The estimated incidence of IK was 34.7 per 100 000 people/year. Of the 1333 corneal scrapes, 502 (37.7%) were culture-positive and 572 causative microorganisms were identified. Sixty (4.5%) cases were of polymicrobial origin (caused by ≥2 different microorganisms). Gram-positive bacteria (308, 53.8%) were most commonly isolated, followed by Gram-negative bacteria (223, 39.0%), acanthamoeba (24, 4.2%) and fungi (17, 3.0%). Pseudomonas aeruginosa (135, 23.6%) was the single most common organism isolated. There was a significant increase in Moraxella spp (p<0.001) and significant decrease in Klebsiella spp (p=0.004) over time. The in vitro susceptibilities of Gram-positive and Gram-negative bacteria to cephalosporin, fluoroquinolone and aminoglycoside were 100.0% and 81.3%, 91.9% and 98.1%, and 95.2% and 98.3%, respectively. An increase in resistance against penicillin was observed in Gram-positive (from 3.5% to 12.7%; p=0.005) and Gram-negative bacteria (from 52.6% to 65.4%; p=0.22).

Conclusion IK represents a relatively common and persistent burden in the UK and the reported incidence is likely underestimated. Current broad-spectrum antimicrobial treatment provides a good coverage for IK, although challenged by some level of antimicrobial resistance and polymicrobial infection.

  • cornea
  • epidemiology
  • infection
  • microbiology
  • ocular surface

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  • DGS and HSD are joint senior authors.

  • Contributors DSJT, DGS and HSD conceptualised the study; DSJT, CH, JC, AE, MA-A and TB collected the data; DSJT performed the data analysis; DSJT, DGS and HSD performed the data interpretation; DSJT drafted the manuscript; all authors critically reviewed and approved the manuscript.

  • Funding DSJT acknowledges support from the Medical Research Council/Fight for Sight Clinical Research Fellowship (MR/T001674/1) and the Fight for Sight/John Lee, Royal College of Ophthalmologists Primer Fellowship (24CO4).

  • Competing interests None declared.

  • Patient consent for publication Not required.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data availability statement All data relevant to the study are included in the article or uploaded as supplementary information. No additional information.

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