Browsing by Author "Yurtsever, SG"

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    Evaluation of Real-Time PCR Method for Rapid Diagnosis of Brucellosis with Different Clinical Manifestations
    Surucuoglu, S; El, S; Ural, S; Gazi, H; Kurutepe, S; Taskiran, P; Yurtsever, SG
    In this study, we tested the advantages of TaqMan real time PCR technique and compare it to conventional methods using serum samples from patients with different clinical forms of brucellosis. A total of 50 patients were included in the study. Blood culture using BACTEC 9240 system, Standard Wright's tube agglutination, and real time PCR methods were used. Control blood samples from 30 people with no history of brucellosis or exposure to Brucella spp. were examined too. Serological assay was positive for 49 patients (98%). Forty-four (88%) of the 50 patients had a positive PCR result, whereas Brucella spp were isolated from blood cultures of 18 patients (36%). STA test was all positive for focal brucellosis. Real time PCR test was positive in 9 patients with focal disease (90%), whereas blood culture was positive only in 4 patients (40%). The sensitivity, specificity, positive and negative predictive values of the real time PCR method were calculated as 88%, 100%, 100%, and 83%, respectively. Our results suggest that the high sensitivity and specificity of real time PCR method make it a useful tool for diagnosis of brucellosis with different clinical manifestations.
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    Significance of Fluorescent In-Situ Hybridization Method in Rapid Diagnosis of Brucellosis
    Gazi, H; Yurtsever, SG; Sürücüoglu, S; El, S; Ertural, P
    Objective: Brucellosis is a zoonosis commonly seen worldwide it causes severe disease and great economic loss. Rapid and sensitive tests are increasingly required for detection of the disease since currently used conventional diagnostic methods give results late and there are some factors affecting its sensitivity. Recently, a number of diagnostic tests have been determined that use different clinical samples in order to diagnose brucellosis in a short time. However a sufficiently sensitive and specific, optimized, routinely applicable molecular method is still lacking for detection of brucellosis which is defined as a difficult infection in terms of diagnosis and treatment. Fluorescent in situ hybridization (FISH) is a novel molecular diagnostic method that can detect Brucella spp. from hemoculture tubes signaling positively by shortening identification time. In this study, we aimed to compare FISH technique with conventional culture method in diagnosis of brucellosis and to investigate its use routinely. Material and Methods: A total of 100 hemoculture samples of patients who applied with the suspicion of brucellosis were studied with FISH and culture methods concurrently, after gram staining. Standard Wright's tube agglutination (STA) test was also used for interpretation of the FISH results. Results: Of the tested samples, 43 studied with cultures, 52 with STA and 44 with FISH were found positive. The FISH detected Brucella spp. in 34 positive cultures and in 29 STA positive sample. Sensitivity, specifity, positive and negative predictive values of FISH method were found as 79.0%, 82.4%, 77.2% and 83.9% respectively when evaluated together with culture which is the gold standard method. Conclusion: FISH is a rapid and easily applicable method not requiring much equipment. However, it was concluded that it could not be used as a cost-effective diagnostic tool as it was not as sensitive enough as desired, and in case of it is used, it would be useful to confirm FISH negative samples with culture and/or serum tube agglutination test.
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    Comparison of Proportion Method in Lowenstein-Jensen Medium with the BACTEC 460 TB System for Antimycobacterial Susceptibility Testing of Mycobacterium tuberculosis Isolates
    Yurtsever, SG; Biçmen, C; Gündüz, AT; Özkütük, N; Salman, S; Demirci, M
    This study was conducted to compare BACTEC 460 TB system and the proportion method in commercially available and ready to use antibiotic added Loweinstein-Jensen (LJ) medium for susceptibility testing of first line drugs in Mycobacterium tuberculosis complex isolates. A total 238 M.tuberculosis strains isolated from clinical samples in our laboratory between 2006-2010 period were included in the study. Susceptibility testing for streptomycin, isoniazid, rifampicin and ethambutol in commercially provided LJ medium (Salubris Inc., Istanbul) was performed by the proportion method as recommended by the manufacturer, and the results were compared with the results of BACTEC 460 TB (Becton Dickinson, USA) system. Resistance rates of M.tuberculosis strains against streptomycin, isoniasid, rifampicin and ethambutol obtained by BACTEC 460 TB system were 19.7%, 42%, 40.8% and 18%, respectively. Those rates were 22.7%, 38.7%, 37% and 15.5%, respectively, by antibiotic added LJ proportion method. There was no statistically significant difference between the two methods in terms of resistance rates (p > 0.05). The rates of consistency between proportion method in LJ medium and BACTEC 460 TB system for streptomycin, isoniasid, rifampicin and ethambutol susceptibility were found as 85.3%, 92.4%, 95.4% and 92.4%, respectively. When comparing the reporting time (interval between beginning of the process to reporting of the results) of the methods, minimal, maximal and average reporting spans for BACTEC 460 TB system were 5, 12 and 8.08 +/- 2.65 days, and 15, 42 and 23.89 +/- 6.02 days for the proportion method in LJ medium, respectively, being statistically significant (p = 0.001). It was determined that the sensitivity test results of major antimycobacterial drugs in commercial LJ medium were compatible with the BACTEC 460 TB system. Nonetheless, the rate of incompatible results was higher for STR than the other drugs. Although there has been some disadvantages such as longer reporting time, need for experience in manual processing and visual evaluation, standardized LJ media approved for quality can be used for susceptibility testing of M.tuberculosis in the laboratories which do not have eligible conditions for the establishment of automated systems.