An Overview of Genetic Information of Latent Mycobacterium tuberculosis / 결핵및호흡기질환

Mycobacterium tuberculosis has infected more than two billion individuals worldwide, of whom 5%–10% have clinically active disease and 90%–95% remain in the latent stage with a reservoir of viable bacteria in the macrophages for extended periods of time. The tubercle bacilli at this stage are usually called dormant, non-viable, and/or non-culturable microorganisms. The patients with latent bacilli will not have clinical pictures and are not infectious. The infections in about 2%–23% of the patients with latent status become reactivated for various reasons such as cancer, human immunodeficiency virus infection, diabetes, and/or aging. Many studies have examined the mechanisms involved in the latent state of Mycobacterium and showed that latency modified the expression of many genes. Therefore, several mechanisms will change in this bacterium. Hence, this study aimed to briefly examine the genes involved in the latent state as well as the changes that are caused by Mycobacterium tuberculosis. The study also evaluated the relationship between the functions of these genes.

Isolation of Stenotrophomonas maltophilia from clinical samples: An investigation of patterns motility and production of melanin pigment

Objectives To investigate possible sources of Stenotrophomonas maltophilia (S. maltophilia) in the clinical environment. Methods Different samples were collected from Amol City of Iran. Steps for the identification of S. maltophilia included culturing, biochemical tests, polymerase chain reaction (PCR) of 16S rRNA gene and 23S rRNA gene. In addition, production of melanin pigment and patterns of motility of the bacteria, were also investigated. Results In our study, 20 S. maltophilia strains were isolated from clinical sources, oxygen manometer apparatus of hospitals were 7/110 (6.36%), blood was 1/777 (0.13%), sputum was 4/40 (4%), urine was 1/2 947 (0.03%), tap water was 1/240 (0.42%) and dental suction was 6/120 (5%). The isolated bacteria showed production of melanin pigment with rates of strong, moderate, weak, and lack of pigment. Types of motilities were seen in isolates. Conclusions The highest percentage of bacteria is isolated of oxygen manometer system and dental suction, yet has not been reported from oxygen manometer system. These bacteria have also been associated with patients who have respiratory problems, so it is essential for staffs of hospitals to draw attention to this source of bacteria.

Evaluating the sensitivity of three primers using PCR-restriction fragment length polymorphism analysis for rapid identification of Mycobacterium simiae isolated from pulmonary tuberculosis patients

Nowadays the molecular methods widely use for rapid identification of Mycobacterium other than tuberculosis [MOTT]. The Mycobacterium simiae isolates are cause of majority of human pulmonary diseases compared with other atypical mycobacteria. As sensitivity of primers and digestion patterns for diversified fragments is different, this survey evaluated the three various fragments using the PCR- restriction fragment length polymorphism analysis [PRA] for rapid diagnostic of M simiae isolates. Strains that were identified as M. simiae [1.7 isolates] by phenotypic [photochromogen and positive niacin] methods were selected for this study. The fragments of the 16S-23S rRNA gene spacer and hsp65 gene were amplified by PCR. Subsequently the amplicons were digested with three restriction enzyme namely Avail, Hphl and Hpall for a 644bp region of hsp65 DNAs, BstEll and Haelll endonucleases for 439bp region of hsp65 gene [TB11 and TB12 fragment] and Haelll digestion for 225bp region of 16S-23S rRNA gene spacer. Of 962 culture positive specimens, 17 [1.7%] were identified as M. simiae species; majority of them were multidrug-resistance [12; 70.5%]. The overall detection rate by Tbll, Tbl2 and SP primers were 82.3% whereas hsp65 primer was 100% [p>0.005]. We also found out that the Hpall and Hphl enzymes were more specific to distinguish M simiae species than other restriction enzyme used in this study. The high discriminative power of hsp65 pattern particularly Hpall digestion, provide an exact and cost-effective method for rapid identification of M. simiae strains among registered pulmonary cases

Determination of asymptomatic Chiamydia trachomatis infections by omp1 gene based-PCR

The objective of this research was to determine the prevalence of genital C. trachomatis infection in asymptomatic women by using highly sensitive nested-polymerase chain reaction [PCR] in urine sample. One hundred-forty asymptomatic women were randomly selected from those who attended gynecology out patient department of Hazraate Rasool Hospital in Tehran. First catch urine specimen were collected from all the participants. DNA extraction was performed by means of High Pure PCR Template Preparation Kit [HPPTP] according to the manufacture's instructions. Extracted DNA was tested by omp1 gene based nested-PCR, using sets of primers to amplify C. trachomatis omp1 gene. Visualization of a 1027 bp fragment from omp1 gene in agarose gel electrophoresis was considered as a positive result. In total, 140 urines were tested for determination of C. trachomatis infection. C. trachomatis omp-1 was detected in 22.1% of cases [31/140]. The overall prevalence rates of C. trachomatis in the urine sample as determined by omp1 based nested-PCR were 4.3% in group I [age, <25 years], 12.1% in group II [age, 25-34 years], 5.0% in group III [age, 35-44 years] and 0.7% in group IV [>44 years]. The highest prevalence of C. trachomatis infection [12.1%] was seen in women aged 25-34 years. This finding was not statistically significant [p=0.710]. Also, there was not relation between C. trachomatis infection and some probable risk factors such as young age [<25 years], STD history and missing use of barrier contraceptive in this study. The prevalence of C. trachomatis infection in the women not seeking health care warrants more comprehensive study using high sensitive omp1 based nested- PCR to identify and treat a large number of infected women in Iran

Determination of distribution of ics A gene and Ics A protein bands between Shigella flexneri isolated from 3 hospitals in Tehran

Shigella is a facultative intracellular pathogen that uses the host actin cytoskeleton protein for intra- and intercellular spread. The aim of this study was to determine the distribution of icsA gene and IcsA expressed protein bands among Shigella flexneri strains isolated from 3 clinical centers in Tehran. Material and Two hundred and seventy five isolated Shigella flexneri strains were identified by standard microbiological and biochemical methods. DNA isolation was performed using sodium perchlorate method. Hot start-PCR was done with 2 pairs of primers and the products were separated through agarose gel [0.8%] in TAE buffer. DNA fragments were visualized by ethidium bromide staining under UV illumination. Whole membrane preparation was used to examine the protein profiles and identification of probable IcsA [120-kda] protein band by SDS-PAGE. From 100 isolated Shigella flexneri strains, both bands of 1600 bp and 1709 bp were detected in 46 isolates [46%]. A 120 kDa band which seems to be related to IcsA protein was detected in 46 isolates [46%]. The protein bands varied between 30 and 150 kDa.Discussion: IcsA is both necessary and sufficient for actin assembly in Shigella flexneri. Since icsA gene and IcsA protein band were not found in all Shigella strains, it seems that not all strains have the same pathogenesis. On the other hand, since the demonstration of icsA gene by PCR in all Shigella strains [46%] corresponded to the presence of a 120 kDa protein band by SDS-PAGE [46%], it seems that both tests may confirm each other. However, the PCR may be more accurate than SDS-PAGE

study of the characteristics of lactobacillus plantarum isolated from sausage in Iran

Introduction: Lactic acid bacteria are widely used for the fermentation and preservation of dairy and meat products and to improve their aroma and texture. The aim of this study was to screen Lactobacillus plantarum isolated from sausage for detection of plasmids, protein bands and phages, to find possible linkage of bacteriocin production to genetic location

Material and Methods: Two Lactobacillus plantarum with antibacterial activity were isolated from sausage. Bacterial plasmids were isolated by alkali lysis and electrophoresis through agarose gel. Proteins were precipitated from cell-free supernatants by ammonium sulphate and analysed by SDS-PAGE. For detection of phages, mitomycin C of final concentration of 2.5 microg/ml was used and phages were detected by transmission electron microscopy

Results: One plasmid of about 4.5 kbp was detected in one Lactobacillus plantarum strain. Two bands of proteins were found on SDS-PAGE. The molecular weight of protein bands of Lacto. plantarum without plasmid was higher than the protein bands of Lacto. plantarum with plasmid. A phage was detected on the cell wall of one strain of Lacto. Plantarum; no plasmid was detected in this Lacto. plantarum. It appears that antibacterial activity is located in the phage of this strain

Conclusion: The high molecular weight of proteins with a wide spectrum effect on bacteria may indicated chromosome-coded bacteriocin. The role of phages in lactobacilli could be a factor which inhibit meat product starter cultures or attributed in antimicrobial activity, i.e. antibacterial genes might be on chromosomal phages. Bacteriophages could be a threat to industrial fermentation foods