Use of a comprehensive polymerase chain reaction system for diagnosis of ocular infectious diseases.

PURPOSE: To measure the genomic DNA of ocular infectious pathogens in ocular fluids and to analyze the clinical relevance of these pathogens in uveitis and endophthalmitis. DESIGN: Prospective clinical case series. PARTICIPANTS: A total of 500 patients with infectious uveitis and endophthalmitis were examined at Tokyo Medical and Dental University, Tokyo Medical University, Kyushu University, Osaka University, and Kyoto Prefectural University, all in Japan. METHODS: Genomic DNA of bacteria, fungi, parasites, and viruses in collected intraocular samples were examined by comprehensive polymerase chain reaction (PCR). Samples were analyzed first by multiplex PCR and quantitative real-time PCR for human herpes viruses (HHVs) 1 through 8 and toxoplasma. Subsequently, samples were examined by broad-range real-time PCR for bacterial 16S and fungal 18S/28S ribosomal DNA (rDNA). MAIN OUTCOME MEASURES: Infectious uveitis and endophthalmitis diagnoses were obtained when using the PCR system. Calculations of the positivity and the diagnostic parameters such as sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) also were evaluated. RESULTS: In all of the tested infectious uveitis and endophthalmitis patients, either herpes simplex virus type 1 (n = 18), herpes simplex virus type 2 (n = 4), varicella-zoster virus (n = 55), Epstein-Barr virus (n = 17), cytomegalovirus (n = 68), HHV type 6 (n = 2), toxoplasma (n = 6), bacterial 16S (n = 33), or fungal 18S/28S (n = 11) genome was detected. Neither HHV type 7 nor HHV type 8 DNA was detected in any of the samples. Of the 21 false-negative results found during the PCR analyses, 12 cases were negative for patients clinically suspected of having bacterial endophthalmitis. Conversely, false-positive results for the comprehensive PCR examinations occurred in only 3 cases that subsequently were found to have bacterial 16S rDNA. Diagnostic parameters for the sensitivity, specificity, PPV, and NPV of our PCR examinations were 91.3%, 98.8%, 98.6%, and 92.4%, respectively. CONCLUSIONS: Use of our comprehensive PCR assay to examine ocular samples in patients with endophthalmitis and uveitis seems to be clinically useful for detecting infectious antigen DNA. Thus, this PCR method is a reliable tool for both diagnosing ocular disorders and further screening of patients for intraocular infections. FINANCIAL DISCLOSURE(S): The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Novel diagnosis of fungal endophthalmitis by broad-range real-time PCR detection of fungal 28S ribosomal DNA.

AIM: To detect the fungal genome in the ocular fluids of patients with fungal endophthalmitis by using a novel broad-range polymerase chain reaction (PCR) system. METHODS: After informed consent was obtained, ocular fluid samples (aqueous humor or vitreous fluids) were collected from 497 patients (76 patients with infectious endophthalmitis including clinically suspected bacterial and fungal endophthalmitis and 421 patients with infectious or non-infectious uveitis). Forty ocular samples from non-infectious patients without ocular inflammation were collected as controls. Fungal ribosomal DNA (28 S rDNA) was measured by a quantitative real-time PCR assay. RESULTS: Fungal 28 S rDNA of the major fungal species, such as Candida, Aspergillus, and Cryptococcus, were detected by novel broad-range real-time PCR examination (>10(1) copies/ml). Fungal 28 S rDNA was detected in the ocular fluids of 11 patients with endophthalmitis or uveitis (11/497, 2.2%). All 11 positive samples were detected in the infectious endophthalmitis patients (11/76, 14.5%). These PCR-positive ocular fluids had high copy numbers of fungal 28 S rDNA (range, 1.7 × 10(3) to 7.9 × 10(6) copies/ml), which indicated the presence of fungal infection. Of the 11 patients who were PCR positive, further examinations led to a diagnosis of fungal endophthalmitis in ten patients. The fungal 28 S rDNA was detected in one non-infectious case (a false-positive case). In addition, there were two PCR false-negative cases that were clinically suspected of having fungal endophthalmitis. CONCLUSIONS: This novel quantitative broad-range PCR of fungal 28 S rDNA is a useful tool for diagnosing endophthalmitis related to fungal infections.

Detection of Candida and Aspergillus species DNA using broad-range real-time PCR for fungal endophthalmitis.

BACKGROUND: The goal of this work is to establish a broad-range real-time polymerase chain reaction (PCR) diagnostic system for ocular fungal infection and to measure Candida and Aspergillus DNA in the ocular fluids obtained from unknown uveitis/endophthalmitis patients. METHODS: After obtaining informed consent, intraocular fluids (aqueous humor and vitreous fluid samples) were collected from 54 patients with idiopathic uveitis or endophthalmitis. Samples were assayed for Candida or Aspergillus DNA using broad-range (18S rRNA sequences) quantitative real-time PCR. RESULTS: Candida or Aspergillus DNA was detected in seven out of 54 patient ocular samples (13%). These PCR-positive samples showed significantly high copy numbers of Candida or Aspergillus DNA. On the other hand, fungal DNA was not detected in any of the other 46 samples collected from these idiopathic uveitis or endophthalmitis patients. In the one PCR-negative case, PCR did not detect any fungal genome in the sample, even though this patient was clinically suspected of having Candida endophthalmitis. Real-time PCR results were negative for fungal DNA in the bacterial endophthalmitis patients and in various uveitis patients. In addition, fungal DNA was also not detected in patients without ocular inflammation (controls). CONCLUSIONS: Analysis of ocular samples by this broad-range real-time PCR method can be utilized for rapid diagnosis of patients suffering from unknown intraocular disorders such as idiopathic uveitis/endophthalmitis.

Cytomegalovirus retinitis in a patient with proliferative diabetes retinopathy.

PURPOSE: To report a case of cytomegalovirus (CMV) retinitis in an immunocompetent patient with proliferative diabetic retinopathy (PDR). DESIGN: Case report. METHODS: A 69-year-old man presented with a 44-year history of diabetes mellitus and 4 years of PDR. Fundus of left eye could not be visualized because of vitreous hemorrhage. Laboratory tests indicated normal immunological status. RESULTS: Yellowish white retinal exudative lesion and whitening inside vascular arcades were observed during vitrectomy. Multiplex PCR using vitreous sample detected CMV DNA at 4.37 × 10(4) copies/mL. CMV retinitis was diagnosed. CONCLUSIONS: If atypical findings of PDR are observed, a multiplex PCR test should be performed for further investigation.

Broad-range real-time PCR assay for detection of bacterial DNA in ocular samples from infectious endophthalmitis.

BACKGROUND: To evaluate a broad-range real-time polymerase chain reaction (PCR) targeting the bacterial 16S rRNA gene for detection of bacterial DNA in infectious endophthalmitis. METHODS: The bacterial 16S rRNA gene was measured by quantitative real-time PCR. For the assay, bacterial DNA was prepared from 12 Gram-positive and 4 Gram-negative strains. To determine the optimum method for DNA extraction, four extraction procedures were selected by using DNA extraction program cards with and without the use of lysozyme. To evaluate PCR sensitivity, PCR fragments were amplified from Staphylococcus aureus and Escherichia coli DNA. RESULTS: DNA extraction using the Bacteria card(®) without enzymes resulted in detection of all the tested strains at concentrations ≥ 10(7) copies/mL. Extraction with the Bacteria card(®) with lysozyme resulted in detection of all the tested strains at concentrations ≥ 10(6) copies/mL, indicative of no significant difference between the two procedures. DNA extraction using the Virus card(®), both with and without enzymes, resulted in reduced efficiency of detection of all strains compared with use of the Bacteria card(®). The PCR could detect as few as 1-10 colony-forming units (CFU) in diluted vitreous samples per reaction, and all tested bacterial species known to cause endophthalmitis were detected. CONCLUSIONS: Bacterial 16S-specific PCR can comprehensively detect the main causative bacteria of clinically suspected endophthalmitis.

Fovea-sparing internal limiting membrane peeling for myopic traction maculopathy.

PURPOSE: To investigate the effectiveness and safety of a new surgical technique of fovea-sparing internal limiting membrane (ILM) peeling for the treatment of foveal retinal detachments (RDs) in eyes with myopic traction maculopathy. DESIGN: Retrospective, consecutive, interventional case series. METHODS: Forty-five eyes of 45 consecutive patients who underwent vitrectomy and ILM peeling for the treatment of a foveal RD attributable to myopic traction maculopathy were studied. The patients were divided into 2 groups by the area of ILM peeled: complete macular ILM peeled group (30 eyes) and fovea-sparing ILM peeled group (15 eyes). A gas tamponade was used in all of the eyes. The main outcome measures were the rate of development of a full-thickness macular hole (MH) and the best-corrected visual acuity (BCVA). All of the patients were followed for more than 6 months. RESULTS: A full-thickness MH developed in 5 of 30 eyes (16.7%) in the complete ILM peeled group and in none of the 15 eyes in the fovea-sparing ILM peeled group. Postoperative OCT examination showed a contraction of the residual ILM on the fovea and reduction of the outer lamellar holes in the fovea-sparing ILM peeled group. The postoperative BCVA was significantly better than the preoperative BCVA in the fovea-sparing ILM peeled group (P = .04), but not in the complete ILM peeled group. CONCLUSIONS: Fovea-sparing ILM peeling results in better visual and anatomic outcomes for the treatment of foveal RD attributable to myopic traction maculopathy. These were accomplished by reducing the development of a full-thickness MH.

Virological analysis in patients with human herpes virus 6-associated ocular inflammatory disorders.

PURPOSE: To determine whether human herpes virus 6 (HHV-6) genomic DNA and mRNA can be detected in ocular samples from patients with inflammatory disorders, and whether viral replication is involved in the development of inflammation in the eye. METHODS: After informed consent was obtained, ocular fluid samples (aqueous humor and vitreous fluids) were collected from 350 patients with uveitis or endophthalmitis. Corneal samples were also collected from 65 patients with corneal infections. Multiplex PCR was performed to screen ocular samples from the patients for HHV-1 to HHV-8. Samples were also assayed for HHV-6 DNA using quantitative real-time PCR. Primers for nested RT-PCR were designed to detect amplification of mRNA (HHV-6 A IE1 U90). RESULTS: PCR results indicated a total of seven patients with uveitis or endophthalmitis (7/350, 2% +) and a single patient with corneal inflammatory disease were positive for HHV-6 DNA (1/65, 1.5% +). These eight patients had high copy numbers of HHV-6 DNA, with values ranging from 4.0 × 10(3) to 5.1 × 10(6) copies/mL. Real-time PCR analysis indicated that two of these cases were HHV-6 variant A and six cases were variant B. In addition, HHV-6 mRNA was clearly detected in vitreous cells collected from one of the patients, suggesting that viral replication may occur in the eye. CONCLUSIONS: Our results indicate that HHV-6 infection/reactivation is implicated in ocular inflammatory diseases.

Diagnosis of ocular toxoplasmosis by two polymerase chain reaction (PCR) examinations: qualitative multiplex and quantitative real-time.

AIM: To establish a two-step polymerase chain reaction (PCR) diagnostic system for ocular toxoplasmosis. METHODS: A total of 13 ocular fluid samples (11 aqueous humor and 2 vitreous fluid) were collected from 13 patients with clinically suspected ocular toxoplasmosis. Ten ocular samples from other uveitis patients and 20 samples from subjects without ocular inflammation were used as controls. Two polymerase chain reaction (PCR) methods, i.e., qualitative multiplex PCR and quantitative real-time PCR, were used to measure the toxoplasma genome (T. gondii B1 gene). RESULTS: Qualitative multiplex PCR detected T. gondii B1 gene in the ocular fluids of 11 out of 13 patients with clinically suspected ocular toxoplasmosis. In real-time PCR, we detected high copy numbers of T. gondii DNA (5.1 × 10(2)-2.1 × 10(6) copies/mL) in a total of 10 patients (10/13, 77%). Only ocular toxoplasmosis scar lesions were observed in the three real-time PCR-negative patients. PCR assay results for the samples from the two control groups were all negative. CONCLUSIONS: The two-step PCR examination to detect toxoplasma DNA is a useful tool for diagnosing ocular toxoplasmosis.

Diagnosis of bacterial endophthalmitis by broad-range quantitative PCR.

AIM: To measure the bacterial genome in ocular fluids and to analyse the clinical relevance of infectious endophthalmitis. METHODS: Nineteen ocular fluid samples (eight aqueous humour and 11 vitreous fluid samples) were collected from 19 patients with suspected bacterial endophthalmitis. Fifty ocular samples from uveitis patients were also collected along with 40 samples from patients without ocular inflammation and used as controls. Bacterial ribosomal DNA (16S rDNA) was measured by a quantitative PCR assay. RESULTS: Bacterial 16S rDNA was detected in patients with clinically suspected bacterial endophthalmitis (18/19, 95%). With the exception of one case, high copy numbers of bacterial DNA were detected (1.7×10(3)-1.7×10(9) copies/ml) in these patients. There were 10 samples (53%) with positive bacterial cultures while there were nine samples (47%) with positive Gram-staining. Real-time PCR detected bacterial 16S rDNA in three (6%) of the 50 samples from the control uveitis patients. In addition, none of the samples from the control patients without intraocular inflammation were positive. CONCLUSIONS: Quantitative broad-range PCR of bacterial 16S rDNA is a useful tool for diagnosing bacterial endophthalmitis.