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[Polymerase chain reaction (PCR) for microbiological diagnosis in refractory infectious keratitis: a clinical study
C P Lohmann1, C Winkler von Mohrenfels, B Gabler
1Augenklinik, Universität Regensburg. chris.lohmann@klinik.uni-regensburg.de
Background:
The identification of the causative pathogen in infectious keratitis is possible in only 60% of the cases. The aim of this study was to show if this number increases by the use of PCR.
Patients And Methods:
In a series of 16 eyes with infectious keratitis corneal specimens were collected for culture and PCR. Serology (HSV, VZV, and Borrelia) was performed in all eyes, with exception of the 4 eyes presenting an acute form of keratitis, which obviously was bacterial origin.
Results:
In all 4 cases of acute keratitis the causative pathogen (Pseudomonas aeruginosa) was detected by both culture and PCR. Of the remaining 12 eyes PCR was capable to identify the causative pathogen in 11 eyes. In 3 eyes herpes simplex virus was detected, in 3 eyes Moraxella catharalis, in 2 eyes Borrelia burgdorferii, in 2 eyes varizella zoster virus, and in 1 eye Bartonella henselae. Culture was positive in only 2 eyes, infected by Moraxella catharalis.
Conclusions:
PCR is a useful supplement in the microbiological diagnostic of infectious keratitis, in particular if only a small amount of pathogens are available (non-acute form) or if the eye has been treated by antibiotics prior to the microbiological diagnostic.
Insights
Polymerase chain reaction (PCR) significantly improves pathogen identification in infectious keratitis cases. This molecular method enhances diagnostic accuracy, especially when pathogen load is low or after antibiotic treatment.
Area of Science:
- Ophthalmology
- Microbiology
- Molecular Diagnostics
Background:
- Infectious keratitis diagnosis relies on identifying the causative pathogen, a feat achieved in only 60% of cases.
- Conventional methods often fail to detect pathogens, necessitating improved diagnostic techniques.
Purpose of the Study:
- To evaluate if Polymerase Chain Reaction (PCR) increases the pathogen identification rate in infectious keratitis.
- To compare PCR's efficacy against traditional culture methods in diagnosing infectious keratitis.
Main Methods:
- Corneal specimens from 16 infectious keratitis patients were analyzed using both culture and PCR.
- Serology for herpes simplex virus (HSV), varicella-zoster virus (VZV), and Borrelia was performed, excluding acute bacterial cases.
Main Results:
- PCR identified the causative pathogen in 11 of 12 non-acute keratitis cases, compared to only 2 positive cultures.
- Specific pathogens detected by PCR included HSV, Moraxella catharalis, Borrelia burgdorferi, VZV, and Bartonella henselae.
- In acute bacterial keratitis, both PCR and culture successfully identified Pseudomonas aeruginosa.
Conclusions:
- PCR serves as a valuable adjunct to microbiological diagnostics for infectious keratitis.
- PCR is particularly beneficial for non-acute cases with low pathogen load or when prior antibiotic treatment has occurred.