Helicobacter pylori in Iran: a systematic review on the association of genotypes and gastroduodenal diseases

Background: Helicobacter pylori (H. pylori) infection is known as a major etiologic factor for a variety of gastroduodenal diseases. In Iran, with a high rate of H. pylori infection close to 90%, numerous studies have revealed many aspects of interaction between the bacterium, mucosal surface and induction of disease outcome. The organism is genetically diverse and several virulence factors are attributed to the more virulent strains. The well-characterized virulence factors of H. pylori are cytotoxin associated gene A and vacuolating cytotoxin gene A. The distribution pattern of H. pylori genotypes and its association with disease status varies geographically. The present review focused on the virulence factors and genotyping of H. pylori in relation to gastroduodenal disorders in different regions of Iran. Methods: In total, 398 studies were reported on different aspects related to H. pylori in our electronic search from 1995-2011. H. pylori infection and its virulence factors in association with disease status were investigated in 159 reports. Looking specifically at the gastrointestinal tract disorders, the most relevant reports including 37 papers were selected. Results: We found no correlation of cagA genotype and disease status in the majority of studies, whereas vacA was demonstrated as a useful marker in predicting the disease outcome. The results of reports on other virulence factors of H. pylori such as blood group antigen-binding adhesion gene A, the induced by contact with epithelium gene A, the outer inflammatory protein A, the duodenal ulcer promoting gene A, and Helicobacter outer membrane gene and their relation with disease status were contradictory. Conclusions: Although different markers of H. pylori were emphasized as useful when predicting disease outcomes in some studies, the inconsistent researches and the scarcity of data made any conclusion or even comparison impossible. Considering the gap of information observed during our search relating to genotyping and other aspects of H. pylori infection, further investigations are suggested

Isolation and Identification of Lactic Acid Bacteria from a Traditional Fermented Fish Sauce (Mahyaveh) in Fars Province, Iran

Background: Mahyaveh is a fermented fish sauce in southern parts of Iran. Lactic acid bacteria (LAB) are commonly dominant microorganisms in fermented fish products. These bacteria develop organoleptic characteristics of fermented foods and play a significant role in promoting their quality and safety. The present study aimed to identify LAB isolated from Mahyaveh using 16SrDNA gene sequences. Methods: Mahyaveh samples were collected from different regions of Fars province, southern Iran. Then, LAB colonies were isolated using specific media and identified by microscopic observations and biochemical tests. Afterwards, DNA was extracted, PCR was done by general primers of 16S rDNA, and the bacteria were recognized. Results: The 16S rDNA sequence of all isolates was related to Lactobacillus plantarum and Enterococcus faecium type strains. Conclusion: L. plantarum and E. faecium were shown to be prevalent LAB strains that could be used as starters in Mahyaveh fermentation in southern Iran

Active participation of student s in teaching

Active participation of students in teaching is the one of the effective way of learning in science education according to large investigation. By this way students understand current level of knowledge, increasing the student’s eagerness and their attraction for learning. This study was designed to explore the effect of active student involvement in teaching and learning of the bacteriology in Isfahan University of Medical Sciences, faculty of Medicine. Material & Methods: Total of 100, medical (n= 50) and nutrition (n= 50) students were participated in this research during two semesters. We started up the session with 2 minutes warming up, 2 minutes for review of previous lecture with asking questions, 35 minutes lectures with repeating and asking questions with students, 5 min summary and end up asking them. We asked students to fill out the questionnaire with 6 questions at the end of semester. Result and discussion: The results of questionnaire analysis showed that there is agreement among students that the bacteriology teaching according to collaborative teaching enhance student learning. Interactive learning environments well serve the variety of students studying bacteriology. In summary, there is large data ccollected by researchers in bacteriology teaching and learning that the traditional lecture base method is not effective in promoting theoretical learning in bacteriology. There is also wide-ranging data that active learning method facilitate well in many different environments

Helicobacter pylori as a zoonotic infection: the detection of H. pylori antigens in the milk and faeces of cows

Background: The prevalence of Helicobacter pylori infection, which may increase the risk of gastritis, peptic ulcers, and cancer, has increased worldwide. This number is estimated to be around 70-90% in developing countries and 25-50% in developed countries. It is possible that the bacterium can be transmitted via food and water as well as zoo-notically and iatrogenically. Because of high prevalence of this infection in Iran, the aim of this study is to examine whether H. pylori infection might be transmitted from cow′s milk and faeces. Methods: The existence of the H. pylori antibody and antigen was investigated in samples of serum, milk, and faeces from 92 lactating Holstein cows in Shahrekord, Iran. The H. pylori antigen and antibody were detected using ELISA and were confirmed by PCR. Results: It was found that out of 92 serum specimens, 25 (27%) of the cows were positive for the H. pylori antibody and 67 specimens were negative. From these 25 seropositive cows, 10 (40%) faeces samples and four (16%) milk sam-ples were antigen positive for H. pylori. Four of the antigen-positive milk specimens were also antigen positive for fae-ces. The existence of the UreC gene was also confirmed in positive samples of milk and faeces. Conclusions: There is a possibility that cow′s milk is a transmission mode in H. pylori infection and faecal contami-nation and inappropriate management processes could transfer H. pylori to humans. The awareness of the H. pylori epi-demiology and its method of distribution are necessary for public health measures and controlling the spread of this bacterium. Further investigation with a greater sample number is necessary to verify the ability of H. pylori transmis-sion via milk consumption

Detection of Helicobacter pylori

Helicobacter pylori infection in human is one of the most common infections worldwide. However, the origin and transmission of this bacterium has not been clearly explained. One of the suggested theories is transmission via water. This study was conducted to determine the prevalence rate of H. pylori in tap water, dental units' water, and bottled mineral water in Iran. In the present study, totally 200 water samples were collected in Isfahan province and tested for H. pylori by cultural method and polymerase chain reaction (PCR) by the detection of the ureC (glmM) gene. Using cultural method totally 5 cultures were positive. Two out of 50 tap water samples (4%), 2 out of 35 dental units' water (5.8%) samples, and 1 out of 40 (2.5% ) from water cooler in public places were found to be contaminated with H. pylori. H. pylori ureC gene was detected in 14 (7%) of water samples including 5 tap water (10%), 4 dental units' water (11.4%), 1 refrigerated water with filtration, and 4 (10%) water cooler in public places samples. This may be due to the coccoid form of bacteria which is detected by PCR method

Detection of Helicobacter pylori in city water, dental units' water, and bottled mineral water

Helicobacter pylori infection in human is one of the most common infections worldwide. However, the origin and transmission of this bacterium has not been clearly explained. One of the suggested theories is transmission via water. This study was conducted to determine the prevalence rate of H. pylori in tap water, dental units' water, and bottled mineral water in Iran. In the present study, totally 200 water samples were collected in Isfahan province and tested for H. pylori by cultural method and polymerase chain reaction (PCR) by the detection of the ureC (glmM) gene. Using cultural method totally 5 cultures were positive. Two out of 50 tap water samples (4%), 2 out of 35 dental units' water (5.8%) samples, and 1 out of 40 (2.5% ) from water cooler in public places were found to be contaminated with H. pylori. H. pylori ureC gene was detected in 14 (7%) of water samples including 5 tap water (10%), 4 dental units' water (11.4%), 1 refrigerated water with filtration, and 4 (10%) water cooler in public places samples. This may be due to the coccoid form of bacteria which is detected by PCR method

Helicobacter pylori in Iran: A systematic review on the antibiotic resistance

Objective(s):Helicobacter pylori (H. pylori) is a pathogenic bacterium that colonizes the stomachs of approximately 50% of the world’s population. Resistance of H. pylori to antibiotics is considered as the main reason for the failure to eradicate this bacterium. The aim of this study was to determine the rate of resistant H. pylori strains to various antimicrobial agents in different areas of Iran.   Materials and Methods: A systematic review of literatures on H. pylori antibiotic resistance in Iran was performed within the time span of 1997 to 2013. Data obtained from various studies were tabulated as following, 1) year of research and number strains tested, 2) number of H. pylori positive patients, 3) study place, 4) resistance of H. pylori to various antibiotics as percentage, and 5) methods used for evaluation of antibiotic resistance. Results: Over the period, a total of 21 studies on H. pylori antibiotic resistance have been conducted in different parts of Iran. In these studies, H. pylori resistance to various antibiotics, including metronidazole, clarithromycin, amoxicillin, tetracycline, ciprofloxacin, levofloxacin and furazolidone were 61.6%, 22.4% ,16.0%, 12.2%, 21.0%, 5.3% and 21.6%, respectively. We found no study on                 H. pylori resistance to rifabutin in Iran. Conclusion: Compared to the global average, we noted that the prevalence of H. pylori resistance to metronidazole, clarithromycin, amoxicillin, and tetracycline has been rapidly growing in Iran. This study showed that in order to determine an appropriate drug regimen against H. pylori, information on antibiotic susceptibility of the bacterium within different geographical areas of Iran is required

The mutation of the rdxA gene in metronidazole-resistant Helicobacter pylori clinical isolates

Backgrounds: Antibiotic resistance is an increasing problem throughout the developed world, and knowledge about different resistance mechanisms is consequential for efficient treatment of bacterial infections. Although metronidazole has been frequently used in treatment regimens for H. pylori infection, but antibiotic resistance is now a major contributing factor in treatment failure. Nevertheless metronidazole has been greatly used as a critical component of combination therapies for H. pylori infection. Objective: This study is trying to describe the mutational mechanisms of metronidazole resistance in H. pylori in our clinical isolates in Isfahanian patients, Iran and compare with the findings of previous studies in world. Materials and Methods: MIC values of metronidazole for H. pylori strains were determined by E- test. Both rdxA and glmM genes used for confirmation of isolates as H. pylori and then amplification of another rdxA oligonucleotide pair was done. Finally, the six resistant strains were sent to sequencing for other processing and further analysis was done by software. Results: The result of six clinical isolates in comparison with 26695, J99 and 69A as a sensitive and resistant reference strains showed plenty of mutations. No frame shift and nonsense mutation was seen in our clinical isolates. Conclusion: An interesting finding in metronidazole-resistant strains in our study was the detection of one mutation not previously described in the literature in the rdxA gene and this W(209)R substitution presumably plays a role in inducing metronidazole resistance

Efflux pump regulatory genes mutations in multidrug resistance Pseudomonas aeruginosa isolated from wound infections in Isfahan hospitals

Background: Multidrug resistance Pseudomonas aeruginosa (MDR-P. aeruginosa) is a worldwide threat for public health. Hyperexpression of efflux pump systems (MexAB-OprM and MexCD-OprJ), which is a well-known mechanisms for MDR emerging, is controlled by regulatory genes, mexR and nfxB, respectively. The aim of this study was to evaluate point mutations in mexR and nfxB genes in MDR- P. aeruginosa isolated from wound infections. Materials and Methods: A total of 34 P. aeruginosa cultures obtained from wound infections were analyzed. Among them eight isolates identified as MDR-P. aeruginosa and were subjected to determination of mutations in mexR and nfxB genes. Results: We detected eight-point mutations in mexR and 12-point mutations in nfxB. The most common mutations were common G327-A (eight isolates), G384-A (eight isolates), G411-A (eight isolates). Mutations in A371-C and A372-C were the predominant substitution which was seen in nfxB. Amino acid substitutions were also found at position 124 and 126 for NfxB and MexR, respectively. Conclusions: P. aeruginosa isolates with mutation in efflux pump regulatory genes such as mexR and nfxB could be a main factor contributed to antibiotic resistance and must be considered in antibiotic treatment