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False positive microbiological results in Acanthamoeba keratitis: the importance of clinico-microbiological correlation

Eye volume 37, pages 3699–3701 (2023)Cite this article

Subjects

We read with interest the study by Hoffman et al. [1]. on diagnostic utility of culture, PCR and in vivo confocal microscopy (IVCM) for infectious keratitis, including Acanthamoeba keratitis (AK). Based on 50 positive AK cases, they demonstrated PCR as a useful diagnostic tool, with good sensitivity (63.3%) and specificity (100%). Extending from their experience, we aimed to highlight the potential of false positive PCR and the importance of clinico-microbiological correlation in AK.

We retrospectively analysed the Nottingham Infectious Keratitis Database between 2008 and 2022. Corneal sampling protocol was previously described [2], and Acanthamoeba DNA PCR analysis was performed at Micropathology (Coventry, UK). Corneal sampling for AK was performed based on clinical suspicion. False positive was defined as resolution of “positive AK” with no anti-acanthamoebic treatment (AAT).

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Fig. 1: Diagnosis of Acanthamoeba keratitis in Nottingham, UK.
Fig. 2: Two cases of presumed Acanthamoeba keratitis with false positive microbiological results (Patient 1: A-D, Patient 2: E-H).

Data availability

All data relevant to this work are provided in this manuscript.

References

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Acknowledgements

We would like to thank Laura Cocking for her assistance in providing us with the list of potential patients with Acanthamoeba keratitis.

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).

Author information

Author notes

  1. These authors contributed equally: Thai Ling Wong, Zun Zheng Ong.

Authors and Affiliations

  1. Department of Ophthalmology, Queen’s Medical Centre, Nottingham, UK

    Thai Ling Wong, Zun Zheng Ong, Dalia G. Said & Harminder S. Dua

  2. Eye Clinic San Giuseppe Hospital, IRCCS Multimedica Scientific Institute, Milan, Italy

    Luca Marelli

  3. G. d’Annunzio University of Chieti, Pescara, Italy

    Arianna Pennacchi

  4. Department of Microbiology, Queen’s Medical Centre, Nottingham, UK

    Michelle Lister

  5. Academic Ophthalmology, School of Medicine, University of Nottingham, Nottingham, UK

    Dalia G. Said, Harminder S. Dua & Darren S. J. Ting

  6. Research Institute of Ophthalmology, Cairo, Egypt

    Dalia G. Said

  7. Birmingham and Midland Eye Centre, Birmingham, UK

    Darren S. J. Ting

  8. Academic Unit of Ophthalmology, Institute of Inflammation and Ageing, University of Birmingham, Birmingham, UK

    Darren S. J. Ting

Authors
  1. Thai Ling Wong
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  2. Zun Zheng Ong
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  3. Luca Marelli
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  4. Arianna Pennacchi
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  5. Michelle Lister
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  6. Dalia G. Said
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  7. Harminder S. Dua
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  8. Darren S. J. Ting
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Contributions

Study conceptualisation and design: DSJT. Data collection: TLW, ZZO, LM, AP, and ML. Data analysis and interpretation: TLW, ZZO, DGS, HSD, and DSJT. Drafting of initial manuscript: TLW and DSJT. Critical revision and final approval of manuscript: All authors.

Corresponding author

Correspondence to Darren S. J. Ting.

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The authors declare no competing interests.

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Informed consent has been obtained from the patients for publishing the eye images.

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Wong, T.L., Ong, Z.Z., Marelli, L. et al. False positive microbiological results in Acanthamoeba keratitis: the importance of clinico-microbiological correlation. Eye 37, 3699–3701 (2023). https://doi.org/10.1038/s41433-023-02573-1

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  • DOI: https://doi.org/10.1038/s41433-023-02573-1

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