Comparison of culture and microscopic methods by PCR for detection of Mycobacterium tuberculosis in sputum

It is difficult to diagnose Mycobacterium tuberculosis infection due to a lack of rapid, sensitive, and specific tests. Newer methods, which are easy and reliable, are required to diagnose TB at an early stage. Our aim is to evaluate the polymerase chain reaction [PCR] technique, using primers directed against the IS6110 gene, for the detection of M. tuberculosis in the sputum samples, and calculate the sensitivity and specificity of PCR. A total of 248 sputum samples from patients suspected of mycobacterial diseases were studied. DNA was extracted by boiling method. IS6110 PCR method by a specific pair of primers designed to amplify 123bp and 245bp sequences of the insertion sequence, 6110, in the M. tuberculosis genome was used to analyze sputum samples. Totally, 32 [12.9%] samples had positive culture. PCR yielded a sensitivity of 93.8% and specificity of 99.1% for the diagnosis of TB, when diagnosis was confirmed by culture. There were 2 out of 32[6.3%] PCR-positive cases among the patients with non-TB disease. We concluded that the performance of an IS6110 PCR assay is valuable in the rapid diagnosis of tuberculosis

Antibiotic resistance patterns of ocular surface bacterial flora

Post operative intraocular infection [endophthalmitis] is a rare but devastating complication. The present study aimed to determine the antibiotic susceptibility pattern of ocular surface bacterial flora isolated preoperatively from patients undergoing intraocular surgery. In a prospective study, 269 patients scheduled for anterior segment surgeries, were enrolled, for whom lid and conjunctival cultures were obtained on the day of surgery before application of povidone - iodine or antibiotic drops. Bacterial isolates were identified and tested for antibiotics susceptibility using Kirby-Bauer disc-diffusion technique. Of 269 studied eyes, 127 [47.2%] were male. In 101 [37.5%] cases bacterial growth was positive. Isolated bacteria in order of frequency were coagulase negative staphylococci [CNS] [90.0%], coagulase positive staphylococci [CPS] [4%], diphteroid [3%], gram negative bacillus [2%] and streptococci [1%]. Totally, 95% of coagulase negative staphylococci were susceptible to vancomycin, amikacin and gentamicin. Less than 70% of isolated CNS were sensitive to ceftriaxon, tetracyelin, erythromycin, oxacillin, cotrimaxazole, and penicillin. Preoperative ocular surface isolates of CNS seems to be most sensitive to vancomycin, amikacin and gentamicin. Thus, preoperative application of these medications into ocular surface is suggested