ABSTRACT
The gold standard method for diagnosis of tuberculosis is the isolation of Mycobacterium tuberculosis through culture, but there is a probability of cross-contamination in simultaneous cultures of samples causing false-positives. This can result in delayed treatment of the underlying disease and drug side effects. In this paper, we reviewed studies on falsepositive cultures of M. tuberculosis . Rate of occurrence, effective factors, and extent of false-positives were analyzed. Ways to identify and reduce the false-positives and management of them are critical for all laboratories. In most cases, falsepositive is occurring in cases with only one positive culture but negative direct smear. The three most crucial factors in this regard are inappropriate technician function, contamination of reagents, and aerosol production. Thus, to reduce false-positives, good laboratory practice, as well as use of whole-genome sequencing or genotyping of all positive culture samples with a robust, extra pure method and rapid response, are essential for minimizing the rate of false-positives. Indeed, molecular approaches and epidemiological surveillance can provide a valuable tool besides culture to identify possible false positives.
ABSTRACT
Objective: To identify serodiagnosis and quantification of Toxoplasma gondii (T. gondii) infection among pregnant women in Salmas, northwest of Iran. Methods: In this cross-sectional study, 276 blood samples were collected from pregnant women referred to the health care centers in Salmas city. The demographic variables were also recorded. Titers of anti-Toxoplasma IgM and IgG antibodies (Ab) were determined using the chemiluminescence immunoassay. Quantitative real-time PCR targeting the T. gondii repeated element gene was also performed on the blood sample. Results: Out of all, 19.92% (55/276) and 2.17% (6/276) patients were seropositive for anti-Toxoplasma IgG and IgM Ab, respectively. Moreover, the presence of T. gondii DNA was observed in 12.31% (34/276) blood samples. A significant relationship was observed between the IgG Ab seropositivity and contact with the cat as a risk factor (P=0.022). Conclusions: The seroprevalence rate of T. gondii infection in pregnant women is relatively low. Consequently, the seronegative pregnant women are at risk, and a considerable rate of positive blood samples for the presence of parasite's DNA should not be ignored. Besides, quantitative real-time PCR could be considered as an accurate method for diagnosis of acute toxoplasmosis especially when the precise results are of the most importance in pregnancy. Limiting contact with cats is also suggested for pregnant women.
ABSTRACT
In recent years, in spite of medical advancement, tuberculosis (TB) remains a worldwide health problem. Although many laboratory methods have been developed to expedite the diagnosis of TB, delays in diagnosis remain a major problem in the clinical practice. Because of the slow growth rate of the causative agent Mycobacterium tuberculosis, isolation, identification, and drug susceptibility testing of this organism and other clinically important mycobacteria can take several weeks or longer. During the past several years, many methods have been developed for direct detection, species identification, and drug susceptibility testing of TB. A good understanding of the effectiveness and practical limitations of these methods is important to improve diagnosis. This review summarizes the currently-used advances in nonmolecular and molecular diagnostics.
Subject(s)
Diagnosis , Mycobacterium tuberculosis , Pathology, Molecular , Tuberculosis , Tuberculosis, Multidrug-Resistant , Tuberculosis, PulmonaryABSTRACT
In order to investigate the molecular diversity of mtDNA in Azeri population, 133 Azeri subjects inhabiting different regions of Azerbaijan [Iran] were selected. Blood samples were taken from these subjects for mtDNA extraction. The extracted mtDNA samples were then studied by the PCR-RFLP method. Fourteen haplogroups were characterized from which 82% were identified as European specific haplogroups. The H haplogroup was the most frequent and 79 haplotypes were specified. In this study, the Iranian Azeri population was found to be a heterogenic population where all the specific haplogroups of Asians, Europeans and Africans were present in the studied population. Comparing the haplogroups of the present investigation with other populations indicated a very close similarity with other Iranian populations, but was different from haplogroups of other Asian populations who also speak the Azeri language
Subject(s)
Humans , DNA, Mitochondrial/genetics , Molecular Biology , Molecular Sequence DataABSTRACT
The present study investigated the role in transmission of M. tuberculosis strains isolated from tuberculosis patients residing in Northwest [East and West Azarbaijan] of Iran. We performed restriction fragment length polymorphism analysis on IS6110 of M. tuberculosis isolated from Northwest Iran. Total of 165 isolates of M. tuberculosis were analyzed by RFLP method. The 5 copies and more IS6110 isolates comprised 30.52% of the total isolates. They formed 16 clustered groups consisting of 2 to 10 cases each. 69.48% of patients had a unique RFLP patterns. Cases from male patients were more clustered than female patients but statistically was not significant [P>0.05]. In this study patients with 56 and older age were strongly associated with clustering [59.6%], which were significantly more than younger patients [P<0.05]. In the present study we found old age as a major risk factor in contact dependent transmission of TB compared to disease recurrence. Unemployment and poor living condition were also among the risk factors in transmission of tuberculosis