title: PCR analysis for assessment of bacterial bioburden in orthokeratology lens cases.
abstract: OBJECTIVE
  To develop a PCR gel analysis method for assessing the bacterial bioburden in orthokeratology contact lens (OK) case fluid determined by culture.
  
  
  METHODS
  A prospective study with the participation of 41 OK wearers (20 girls, 21 boys) was performed. The mean OK-wearing experience was 3.5±1.9 years. PCR was used to assess the bacterial bioburden (colony-forming units per milliliter) of OK after removal and soaking in the storage case for 6 h. The signal intensity of the PCR bands was analyzed after grayscale image transformation. The difference (cPCR-d) and ratio (cPCR-r) between a PCR signal and its background were used as two standardized indices of PCR signals. The association between the two indices of the PCR signals and the bacterial bioburden determined by culture were analyzed with Pearson's correlation coefficient (r) and receiver operating characteristic (ROC) plots.
  
  
  RESULTS
  At least one microbe was isolated from the OK lens case from 38 of the 41 subjects. Both cPCR-d and cPCR-r showed strong correlations with the bacterial bioburden (r>0.7, p<0.0001). ROC analysis enabled good determination of the cutoff values for the two PCR indices with acceptable sensitivity and specificity (78-89%) to assess the degree of bacterial contamination.
  
  
  CONCLUSIONS
  The high microbial contamination rate of the OK lens cases revealed the general inappropriate lens care by OK wearers. PCR analysis provides an alternative and rapid method for assessing the bacterial bioburden of OK lens cases, and these results should serve as a warning to OK wearers to follow appropriate lens care procedures to prevent infection.
authors.affiliation: Department of Ophthalmology, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan.
authors.forename: Jung
authors.initials: J
authors.lastname: Lo
authors.affiliation: Department of Ophthalmology, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan.
authors.forename: Po-Chiung
authors.initials: PC
authors.lastname: Fang
authors.affiliation: Department of Laboratory Medicine, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan.
authors.forename: Chun-Chih
authors.initials: CC
authors.lastname: Chien
authors.affiliation: Graduate Institute of Clinical Medical Sciences, Chang Gung University, Taiwan.
authors.forename: Chang-Chun
authors.initials: CC
authors.lastname: Hsiao
authors.affiliation: Department of Ophthalmology, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan.
authors.forename: Shin-Ling
authors.initials: SL
authors.lastname: Tseng
authors.affiliation: Department of Ophthalmology, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan.
authors.forename: Yu-Hsuan
authors.initials: YH
authors.lastname: Lai
authors.affiliation: Department of Ophthalmology, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung, Taiwan.
authors.forename: Ming-Tse
authors.initials: MT
authors.lastname: Kuo
mesh_terms: D000293:Adolescent; D001419:Bacteria / Q000302:isolation & purification*; D018407:Bacterial Physiological Phenomena; D018441:Biofilms / Q000254:growth & development; D002648:Child; D003261:Contact Lenses / Q000382:microbiology*; D004269:DNA, Bacterial / Q000032:analysis*; D004866:Equipment Contamination; D005260:Female; D006801:Humans; D008297:Male; D054158:Orthokeratologic Procedures / Q000295:instrumentation*; D016133:Polymerase Chain Reaction; D019064:Product Packaging; D011446:Prospective Studies
chemical_list: D004269:DNA, Bacterial