Purpose: To detect T. gondii DNA and specific antibodies in lens aspirates (LA) and peripheral blood leucocytes (PBL) of congenital cataract patients. Methods: ELISA for T. gondii antibodies on sera nPCR for T. gondii DNA (B1 gene) on LA and PBL were performed for 52 patients. Results: T. gondii DNA was detected in 29 (55.8%) of the 52 patients (LA-14, PBL-13, LA and PBL-2, and specific IgM in 2 sera). nPCR in PBL was more sensitive than ELISA (p < 0.005). Conclusion: nPCR is a sensitive technique to detect T. gondii from LA and PBL in congenital cataract patients.
Orbital tuberculosis is quite uncommon. We report a case of orbital tuberculosis in a 3-year-old child from Bangladesh who presented with swelling and discharging sinus in the lower part of the orbit. Histopathology revealed a granulomatous inflammation with caseation necrosis. Polymerase chain reaction (PCR) showed amplification of the Mycobacterium tuberculosis genome. The patient responded to a course of antituberculous treatment. Mycobacterium tuberculosis should be considered in the differential diagnosis of inflammatory orbital disease in the Indian subcontinent where tuberculosis is prevalent.
Nucleic acid amplification using IS6110 primers to detect Mycobacterium tuberculosis in clinical specimens has been extensively used as laboratory tool for the diagnosis for tuberculosis. Despite it's dramatic scientific value in practice, it is not as sensitive as expected for the detection of Mycobacterium tuberculosis. The results of the study suggest that PCR using 123 bp fragment of DNA belonging to IS6110 is specific (95.6%) but only has a sensitivity of 30% to detect M. tuberculosis in clinical specimens.
Summary Background: Multiple Drug Resistant Tuberculosis (MDR-TB) is increasing because of widespread application and results in selection of mutants resistant to other components of short course chemotherapy. Resistance to Rifampicin can be considered as a surrogate marker for MDR-TB and the target gene for detection of rifampicin resistance is the rpo gene. Aims: To detect and characterize mutations in the rpo B region of Rifampicin resistant isolates of Mycobacterium tuberculosis by automated DNA sequencing. Methods: Absolute concentration method was used to determine the MIC of Rifampicin for 44 M. tuberculosis isolates (21 respiratory, 3 ocular, 3 cerebrospinal fluid and 17 biopsies). Automated DNA sequencing was performed in the ABI 310 Genetic Analyser. Results: Five isolates (2 sputa and one each from bronchoalveolar lavage, lymph node and endometrial biopsies) were rifampicin resistant with MIC greater than 128 mg/ml. Three of the five isolates showed mutations. Two of the isolates had the common missense mutation at codon 531(Ser®Leu), the other isolate showed three insertions and two of them did not show any mutation in the sequenced rpo B region. Conclusions: DNA sequencing technique is a rapid, conclusive and more advantageous technique than the conventional susceptibility testing for detection of rifampicin resistance in terms of the risk involved and time consumption.
This is to report a case of bacteremia caused by Salmonella typhi in a treated unilateral fungal endogenous endophthalmitis in an 18-year-old male from one of the South Asian countries. Microbiological and molecular investigations were carried out on the eviscerated material and routine blood culture was carried out. Direct examination of eviscerated material revealed the presence of fungal filaments. However, Salmonella typhi was isolated from both specimens, which was confirmed by Polymerase chain reaction targeting the 16SrRNA gene, sequencing, and random amplification of polymorphic DNA showed that they belonged to the same clone. The presence of Salmonella bacteremia in a treated unilateral fungal endophthalmitis, among young adult patients is rare and systemic symptoms should be investigated.
Purpose: Multidrug-resistant TB (MDR-TB) has been reported in almost all parts of the world. Childhood TB is accorded low priority by national TB control programs. Probable reasons include diagnostic difficulties, limited resources, misplaced faith in BCG and lack of data on treatment. Good data on the burden of all forms of TB among children in India are not available. Objective: To study the drug sensitivity pattern of tuberculosis in children aged from 3 months to 18 years and the outcome of drug-resistant tuberculosis by BACTEC culture system and PCR-based DNA sequencing technique. Materials and Methods: This is a retrospective study. One hundred and fifty-nine clinical specimens were processed for Ziehl-Neelsen stain, Mycobacterial culture by BACTEC method, phenotypic DST for first-line drugs for Mycobacterium tuberculosis (M. tuberculosis) isolates and PCR-based DNA sequencing was performed for the M. tuberculosis isolates targeting rpoB, katG, inhA, oxyR-ahpC, rpsL, rrs and pncA. Results and Conclusion: Out of the 159 Mycobacterial cultures performed during the study period, 17 clinical specimens (10.7%) were culture positive for M. tuberculosis. Among the 17 M. tuberculosis isolates, 2 were multidrug-resistant TB. PCR-based DNA sequencing revealed the presence of many novel mutations targeting katG, inhA, oxyR-ahpC and pncA and the most commonly reported mutation Ser531Leu in the rpoB gene. This study underlines the urgent need to take efforts to develop methods for rapid detection and drug susceptibility of tubercle bacilli in the pediatric population.
Transient nasolacrimal duct obstruction secondary to a mass lesion compressing the sac or sac-duct junction is rare. The authors report a case of a young female who presented to the authors with complaints of watering and a mass lesion in the lacrimal sac region. An organized perilacrimal mass filled with thick pultaceous material was noted during surgery. Following the drainage of the mass lesion, irrigation of the lacrimal system was freely patent. Microbiological examination and DNA sequencing targeting interspacer region was suggestive of Pleurostomophora richardsiae species. To the best of the authors' knowledge, this is only the second case report of a subcutaneous perilacrimal mass causing transient nasolacrimal duct obstruction by Pleurostomophora richardsiae.