ABSTRACT
Purpose: To evaluate the correlation of quantitative real?time polymerase chain reaction (qRT?PCR) to the clinical characteristics of patients with viral retinitis.Methods: Retrospective case series. Results: Aqueous or vitreous samples of 20 out of 35 eyes showed qRT?PCR positivity for virus etiology (57.14%). Cytomegalovirus (CMV) was most commonly identified in nine eyes (45%). The mean DNA copy number was 2,68,339.65 copies/mL (range: 90–3205397). DNA copy number significantly correlated with the extent of clinical involvement (P = 0.013); however, there was no correlation between DNA copy number and presenting visual acuity (P = 0.31), macular involvement (P = 0.675), optic nerve involvement (P = 0.14), and development of retinal detachment (P = 0.73). There was a significant correlation between the number of DNA copies and the timing of sampling (P = 0.0005). Samples taken earlier in the course of the disease had higher viral copies than later ones. Conclusion: qRT?PCR is useful in confirming a viral etiology in over 50% of cases of suspected viral retinitis. It correlates well with the extent of clinical involvement and timing of sampling
ABSTRACT
The purpose of the study was to report a case of ulcerative keratitis caused by an unusual algae Prototheca wickerhamii in a diabetic patient. This study design was a case report. A 46-year-old male, who was a known diabetic for 3 years, had an injury to the left cornea with the sparks of fire from wielding at work that developed into an ulcerative keratitis over a period of next 3 months as the patient was not on any medication. Corneal scraping culture report and Vitek 2 system investigation result confirmed it to be a P. wickerhamii infection. The patient was started on intensive topical 1% voriconazole and 5% natamycin for 1 month and with no improvement subsequently underwent penetrating keratoplasty. No recurrence of infection postoperatively was noted. This opportunistic algae rarely known to cause human eye infections is so far reported in either patients with severe systemic immunosuppression causing posterior segment eye involvement or as postcorneal surgery infections. We report an ulcerative keratitis by P. wickerhamii in a diabetic patient post corneal trauma with no prior ocular surgery.
ABSTRACT
Background: Early diagnosis of tuberculosis is critical for its effective management and prevention. Several gene amplifi cation methods are used in the detection of tubercle bacilli from clinical specimens. MPB64 gene and IS6110 region have been identifi ed as potential gene targets for the specifi c detection of Mycobacterium tuberculosis from direct clinical specimens. Objective: The present study was conducted to evaluate the diagnostic utility of simultaneous application of two nested polymerase chain reaction (nPCRs) targeting MPB64 and IS6110 region for the detection of M. tuberculosis genome. Materials and Methods: A total of 100 and 354 clinical specimens from the control group and clinically suspected tuberculosis patients, respectively, were included in the study. nPCRs targeting MPB64 and IS6110 region were performed. Results and Conclusion: All of the 100 clinical specimens from the control group were negative for both nPCRs. Out of the 354 clinical specimens, 339 were positive for both culture and nPCRs, 10 and 5 were positive for culture, and nPCR targeting IS6110 and MPB64 regions, respectively. To conclude, nPCRs targeting MPB64 and IS6110 region are reliable and specifi c targets when applied simultaneously on clinical specimens to attain 100% sensitivity for the detection of M. tuberculosis genome.
ABSTRACT
Background & objectives: mRNA is more rapidly destroyed in cells than rRNA or genomic DNA, an assay targeting bacterial mRNA would provide a better guide to mycobacterial viability than amplification tests directed at DNA or rRNA targets. This study was carried out to standardize reverse transcriptase PCR (RT-PCR) targeting 85B gene for the rapid detection of viable Mycobacterium tuberculosis from sputum specimens of suspected TB patients at Chennai, South India and to detect MDR-TB circulating in this population. Methods: Sputum samples from clinically suspected tuberculosis patients (n=301) and 78 controls were included in the study. The sputum samples were collected in sterile diethyl pyrocarbonate (DEPC) treated containers and transported in ice to the laboratory within 2 h to prevent degradation of RNA. RT-PCR targeting 85B gene, mycobacterial culture and phenotypic drug susceptibility testing for the first line drugs streptomycin (S), isoniazid (H), rifampicin (R), ethambutol (E) and pyrazinamide (Z) were performed by BACTEC microMGIT culture system for all the sputum specimens. Results: All the 78 controls were negative for culture and RT-PCR. Among the 301 sputum specimens from patients, 231 (76.8%) were RT-PCR positive and 70 (23.2%) were negative. There were 166 M. tuberculosis isolates, of which 11 (2.9%) were MDR-TB, 33 (8.7%) were polyresistant, 31 (8.2%) were monoresistant and 91 (30.2%) were sensitive to all five first line anti-tuberculous drugs by phenotypic drug susceptibility testing. Monoresistance was higher with Z [20 (20.8%)], followed by S [6 (3%)]. Interpretation & conclusions: RT-PCR targeting 85B gene of M. tuberculosis was a specific, rapid, reliable technique to detect the M. tuberculosis directly from sputum specimens. Our results showed that 2.9 per cent of M. tuberculosis isolates in the study population of Chennai were MDR.