Comparison of mycobacterial interspersed repetitive unit-variable number tandem repeat and IS6110-RFLP methods in identifying epidemiological links in patients with tuberculosis in Northwest of Iran

Genotyping of Mycobacterium tuberculosis complex isolated from humans and animals in northeastern Iran

The objective of this study was to genotype Mycobacterium tuberculosis complex isolated from humans and cattle in northern Iran. Over the course of one year, a total of 120 human and 21 cattle isolates were tested using region of difference (RD)-based polymerase chain reaction (PCR) and mycobacterial interspersed repetitive unites-variable number tandem repeats (MIRU-VNTR). In M. tuberculosis, out of 120 isolates investigated, the most common genotype detected was NEW-1 (53.3%), followed by CAS/ Delhi (24.1%), Haarlem (5%), Beijing (4.16%), Uganda I (4.16%), S (3.3%), Ural (0.83%), TUR (0.83%), Uganda II (0.83%), Lam (0.83%) and Cameroon (0.83%). The HGDI rate was 0.9981 and the clustering rate was 10.83. Of the isolates, QUB26 had the highest allele diversity (h: 0.76), while the loci Mtub29 and MIRU24 had the lowest (h: 0). In M. Bovis, out of 123 collected tissue samples, 21 (17%) grew on culture media. The HGDI rate was 0.71 and clustering rate was 85.7%. The locus ETRC had the highest allele diversity (h: 0.45). The findings of this study suggest that there is high genetic diversity among M. tuberculosis isolates in Khorasan Razavi Province, which is consistent with similar results from other studies in other provinces in Iran and neighboring countries. This indicates that the prevalent genotypes in this study are spreading in the Middle East region. Furthermore, considering that M. Bovis isolates were identified in two clusters, it seems that all of them have a common origin and are circulating among the livestock farms in the province.

Long non-coding RNA molecules in tuberculosis

Tuberculosis (TB), a chronic disease caused by Mycobacterium tuberculosis, is one of the deadliest infectious diseases in the world. Despite significant advances in detection techniques and therapeutic approaches for tuberculosis, there is still no suitable solution for early screening and reducing the number of individuals affected and their effective treatment. Various cellular events can disrupt the development of TB. The basis of these events is dysregulating of genes expression patterns related with specific molecules. Long non-coding RNAs (lncRNAs) are molecules discovered to regulate the expression of protein-coding genes and participate in gene silencing, cell cycle regulation and cellular differentiation processes. Dysregulation of lncRNAs has been found to be associated with many diseases, including cancers and infectious diseases. Thus, the recognition of lncRNAs as novel molecular biomarkers and therapeutic targets for tuberculosis is promising. In the present review, we try to summarize the current findings of lncRNA expression patterns and its role in tuberculosis infection process.

Molecular Diversity of Mycobacterium tuberculosis Strains in Northwestern Iran

Background

Years after the development of antituberculosis (TB) drugs, many people continue to suffer from this disease. To control the spread of TB, strains of the Mycobacterium tuberculosis complex need to be determined, and sources of infection must be identified. Such steps should help to prevent transmission of the infection.

Objectives

The aim of this study was to perform molecular genotyping of isolates of the M. tuberculosis complex obtained from patients in northwestern Iran.

Methods

One hundred ninety-four culture-positive M. tuberculosis isolates obtained from patients in northwestern Iran were analyzed using the mycobacterial interspersed repetitive unit-exact tandem repeats (MIRU-ETR) method.

Results

The MIRU-ETR method distinguished 162 different patterns in the 194 isolates, comprising 23 clusters and 139 unique patterns. Its discriminatory power according to the Hunter-Gaston discriminatory index (HGDI) was 0.9978. The largest cluster contained six isolates.

Conclusions

This research indicated that various strains of M. tuberculosis were responsible for TB and that the majority of cases were due to reactivation.

Role of Enterotoxigenic Bacteroides fragilis in Children Less Than 5 Years of Age With Diarrhea in Tabriz, Iran

Background

Diarrhea is the most frequent health problem among children in developing countries. Defining the etiology of acute diarrhea is critical to disease therapy and prevention. Some anaerobic bacteria such as Enterotoxigenic Bacteroides fragilis (ETBF) strains cause diarrheal disease by production of enterotoxin in children less than 5 years old.

Objectives

This study aimed to evaluate the prevalence of ETBF among common bacteria and viruses causing diarrhea in children aged less than five years.

Materials and Methods

One hundred diarrheal stools were cultured for detection of aerobic and anaerobic pathogen bacteria by direct plating on selective media and antibiotic susceptibility tests were performed according to clinical and laboratory standards institute (CLSI) guidelines on isolates of ETBF. The enterotoxigenic gene among B. fragilis isolates was also investigated using the polymerase chain reaction (PCR) method. Detection of viral pathogens was carried out using the latex agglutination test.

Results

Ten B. fragilis were isolated from 100 diarrheal fecal specimens. All isolates were susceptible to metronidazole, while 10% were susceptible to clindamycin. Four (40%) ETBF were isolated. Rotaviruses (57.2%) and adenoviruses (18.6%) were the most frequently detected etiological agents.

Conclusions

ETBF is one of the etiological agents that may cause diarrhea in children but it is not the commonest of them. Metronidazole is still an effective antibiotic against B. fragilis. Viruses are the most important etiological agents of diarrhea in children less than 5 years of age.