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Abstract Background and objectives: Diarrhea is one of the main cases of morbidity and mortality among children in developing countries. Enteroaggregative Escherichia coli (EAggEC) is an emerging diarrheal pathogen that has been associated characteristically with persistent diarrhea among infants, particularly in the developing Counties. Therefore, we decided to study the prevalence of enteroaggregative strain in cases of Diarrhea in Gorgan by PCR method. Material and Methods: This descriptive study was carried out on 455 subjects suffered from Diarrhea in Gorgan during one year (2005-6). At first, the samples were cultivated on the MacConkey agar and EMB agar media, Then all colony Suspected to E.coli were chosen and their DNA extracted by phenol chloroform method. The result was obtained by the selected primer, PCR method. Results: of 455 samples, Twenty cases (4/4%) including men (12) and woman (8) are positive for EAggEC, 85% of sufferers are under 5 years old (45.8% of them are under one year old). The Prevalence of this gene in Summer , Autumn ,Winter ,Spring are 5.3% , 4.2% , 4.1% and 1.8% ,respectively. Conclusion: Based on the prevalence of Enteroaggregative Escherichia coli (EAggEC) in Diarrheagenic cases in Gorgan (4.4%), we do recommend using molecular methods, which are reliable and less expensive than classic methods, in detecting of microorganisms. Key words: Entroaggregative Escherichia coli, Diarrhea, PCR, Gorgan.

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Abstract Background and Objectives: Diarrhea is one of the most common diseases in the world. Campylobacter jejuni is one of the prevalent agents of bacterial diarrhea in most of developing countries. It is usually ignored in routine laboratory test in our country, because it has a difficult investigation method. This article aims to determine the prevalence of Campylobacter jejuni, in diarrhea samples in Gorgan City (East north of Iran) by PCR Method. Material and Methods: This descriptive study was performed on 455 diarrheal samples during one year (2005-06).255 out of them were cultured on Preston media (Himedia co.) on 42°c. DNA Extracted by phenol cholorophorm method was directly carried out on stool samples.16srDNA hipo and asp primers for detection of Campylobacter genus, C.jejuni and C.coli species were used, respectively. In addition, universal primer of 16srDNA was used for control of PCR method. Results: no sample was positive for Campylobacter in culture .only three samples were positive for Campylobacter genus and C.jejuni specific primer but none of them were positive for C.coli .99 samples were positive by universal primer of 16srDNA . Conclusion: The results indicate that C.jejuni isn't a prevalent agent in diarrhea in our region. Key words: Campylobacter jejuni -Gorgan- Diarrhea

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Abstract Background and objectives: With almost nine million new cases each year, tuberculosis is still one of the most Life-threatening diseases in the World. Distribution of drug resistant strains of M.tuberculosis has a lot of importance. This research was carried out to determine the frequency of drug resistance of M. tuberculosis in strains isolated in Golestan province. Material and Methods: In this cross -sectional study, 104 isolate of M.tuberculosis which isolated from patients referred to Gorgan tuberculosis Health Center, in 2008 were studied. DNA was extracted by Boiling Method. By using PCR method, we determine the M.tubeculosis strain and resistance to Rifampin (Using IS6110 and Gene rpoB primers) and resistance to Isoniazid (Using InhA and KatG primers). As a Gold Standandard, “Proportional method” was performed for 45 Samples. Results: 87 strains were identified as M.tuberculosis. 6.9% of them were resistant to Isoniazid, 4.6% to Rifampin and 2.3% to both (MDR).Sensitivity and Specifity of PCR method in detection of resistant to Isoniazid were 95.3% and 57.1% and for Rifampin were 94.7% and 33.3%. Conclusion: We found that in our region, the MDR is not very common. More than 16% of isolated strains from tuberculosis suspected patients were MOTT, for this reason it is necessary to mention that use biochemical or PCR method to determine M.tuberculosis is necessary. Key words: Mycobacterium tuberculosis, MDR, PCR, Proportional method , Golestan province.

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Abstract Background and Objective: The main cause of spreading staphylococcal infections among patients is the healthy carriers working in hospitals. With the secretion of different sorts of toxins such as entrotoxin, this bacteria can provide the conditions for attacking on the host. The main objective of this study is identification of the characteristics and differences in the Staphylococcus aureus isolated from healthy carriers and from the patients on the basis of enterotoxin genes (sea-see). Material and Methods: One hundred and twenty of the patients and 80 of healthy carriers worked in health centers of Gorgan, north of Iran, were investigated for S. aureus isolate. The isolates were evaluated by PCR for Enterotoxin Genes A-E (SEA to SEE). Results: Enterotoxin genes (SEA to SEE) was found in 87.5% of the total isolates and the most frequent one was enterotoxin gene sea (N= 124). The prevalence of these isolates in healthy carriers was significantly higher than those of the patients. Conclusion: Based on the results, the high percentage of S. aureus isolated from clinical samples contains enterotoxin genes. Therefore, Human as the source and carrier of S. aureus is paramount importance, which is due to significant relationship between being toxigenic strains and the source of isolation. Key words: Staphylococcus Aureus Enterotoxin Patient Carrier