Assessment of polymerase chain reaction in the detection of pseudomonas aeruginosa in contact lens-induced severe infectious keratitis.
OBJECTIVE
The aim of this study is to evaluate the role of real-time polymerase chain reaction (PCR) and conventional bacterial culture methods in the detection of Pseudomonas aeruginosa in contact lens-induced severe, partially treated corneal ulcers referred to a tertiary center.


METHODS
The study duration was 6 months. All patients with contact lens-related corneal ulcer, requiring admission during the study period were recruited. Samples from corneal scrapings were simultaneously sent at the time of admission for PCR and culture testing. An in-house real-time PCR was developed to detect the P. aeruginosa lasA gene. The results of PCR and culture were compared using McNemar's chi2 test.


RESULTS
Ten patients were recruited. The mean age was 33 years (20-45 years). All the patients had contact lens-related keratitis (>4 mm) of which eight (80%) were found positive for P. aeruginosa by PCR or culture. There was no significant difference between PCR and culture in detecting P. aeruginosa (P<0.05).


CONCLUSIONS
PCR is, at least, as good as conventional cultures in detecting P. aeruginosa. It is a rapid assay as compared with culture, and early detection enables prompt treatment thus reducing the destructive effect of the organism on the cornea.
Department of Ophthalmology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia.
Visvaraja
V
Subrayan
Mohammadreza
M
Peyman
Soon
S
Lek Yap
Nadir Ali
NA
Mohamed Ali
Shamala
S
Devi
D000328:Adult; D002442:Ceftazidime / Q000008:administration & dosage / Q000627:therapeutic use; D002939:Ciprofloxacin / Q000008:administration & dosage / Q000627:therapeutic use; D003261:Contact Lenses / Q000009:adverse effects / Q000382:microbiology*; D004269:DNA, Bacterial / Q000032:analysis*; D003937:Diagnosis, Differential; D004305:Dose-Response Relationship, Drug; D004359:Drug Therapy, Combination; D015818:Eye Infections, Bacterial / Q000175:diagnosis* / Q000188:drug therapy / Q000382:microbiology; D005260:Female; D006801:Humans; D007634:Keratitis / Q000175:diagnosis* / Q000188:drug therapy / Q000382:microbiology; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction / Q000379:methods*; D011552:Pseudomonas Infections / Q000175:diagnosis* / Q000188:drug therapy / Q000382:microbiology; D011550:Pseudomonas aeruginosa / Q000235:genetics* / Q000302:isolation & purification; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012720:Severity of Illness Index; D055815:Young Adult
D004269:DNA, Bacterial; D002939:Ciprofloxacin; D002442:Ceftazidime