shohreh farshad

Cytotoxin-associated gene A (cagA) is an important virulence factor in the pathogenesis of Helicobacter pylori. .
The aim of this study was to genotype the H. pylori cagA gene isolated from antral biopsies of patients with stomach symptoms, using a PCR-restriction fragment length polymorphism (PCR-RFLP) analysis..
Patients and A total of 161 gastric biopsies were collected from patients with stomach symptoms. After isolation of H. pylori from the biopsy culture, the cagA gene was assessed using PCR. The PCR products were then digested by the HinfI restriction endonuclease enzyme. A sample of each genotype was also subjected to direct sequencing for further analysis..
From 161 antral biopsies, 61 (37.9%) were positive for H. pylori in culture. Overall, 24 cagA-positives were detected in the isolates. RFLP indicated three different genotypes (I, II, and III) of cagA with a frequency of 62.5%, 25%, and 12.5% among the isolates, respectively. Genotypes I and II of cagA were predominant in patients who had gastritis. However, genotype III was found in three patients with duodenitis and duodenal ulcers. Alignment of the nucleotide sequences of the three isolated genotypes, with H. pylori 26695 as a reference strain, revealed 12 inserted nucleotides in genotype III. When the sequence of genotype III was aligned with 15 additional H. pylori strains available in GenBank, the same inserted nucleotides were detected in six of them. .
Using the PCR-RFLP method, three distinctive H. pylori cagA genotypes were detected in antral biopsies. Genotype I, which was predominant among the isolates, was significantly associated with gastritis. However, the data showed that cagA genotype III may play a role in duodenitis and duodenal ulcers in patients infected with H. pylori..

Identification, understanding of antibiotic sensitivity patterns and molecular characterization of genetic elements of Shigella species are important because of both epidemiological and clinical indications in developing countries. The aim of this study was to analyze molecular epidemiology of Shigella isolates recovered from children with diarrhea in Shiraz (Southern Iran), using IpaH and IpaBCD PCR-restriction fragment length polymorphism (RFLP), and to determine pulsed field gel electrophoresis (PFGE) patterns of total DNA of the S. sonnei isolates to find the clonality among these strains.Patients and A total of 82 clinical strains of Shigella spp., S. sonnei (n = 61), S. flexneri (n = 16), Shigella boydii (n = 3) and S. dysenteriae (n = 2) isolated from the stool samples of 719 patients, aged two months to 14 years, with positive occult blood (OB) test were characterized based on their IpaH and IpaBCD genes PCR-RFLP patterns. Genomic DNAs of S. sonnei strains were analyzed by PFGE. All Shigella isolates were positive for both invasive genes and showed homogeneous profiles for such genes except for two S. sonnei strains, which had IpaH bands with different sizes and PCR-RFLP profiles. Forty palsotypes were determined among the 41 S. sonnei strains. Sample patterns were divided into two groups based on the drawn dendrogram with a similarity range of 70% to 100%. The results revealed that the strains under study could be epidemically related. It seems that an alternative subtyping method is needed to study the relationship among clinical S. sonnei strains and their transmission. Here, we reported for the first time, two strains of S. sonnei with a different PCR-RFLP pattern for IpaH gene.

Alkylhydroperoxide reductase (AhpC, the 26 kDa antigen) is one of the abundant antioxidant enzymes in Helicobacter pylori and seems to have a good potential for use in development of immunoassays to detect H. pylori infection in clinical specimens. This study aimed to investigate some properties of this antigen by the produced monoclonal antibodies.Five established hybridoma cell lines secreting monoclonal antibodies (MAbs) against 26 kDa antigen of H. pylori were cultivated and MAbs were purified by affinity chromatography. Subsequently, MAbs were conjugated with biotin, and different combinations of capture and tracer antibodies used in sandwich ELISA. Immunoblotting of bacterial extracts were performed to estimate aggregation status of the antigen. Release of antigen from the cultivated bacteria on solid media was examined by sandwich ELISA, and also, existence of interference in fecal extract was investigated by immunoblotting and sandwich ELISA.Our findings showed that the MAbs against 26 kDa antigen of H. pylori could recognize three bands of nearly 25 kDa, 50 kDa, and 75 kDa in immunoblotting. This study also indicated presence of more antigens in the culture medium around the bacteria than the bacterial extract itself. The results of sandwich ELISA and immunoblotting on fecal extracts suggest the presence of interfering agents that prevent detection of antigen by antibody in ELISA but not in immunoblotting.In this study the oligomerization of the 26 kDa antigen, presence of interfering agents in stool matrix, and release of antigen to outside of bacteria, were demonstrated.

One of the common nosocomial bacteria is methicillin resistant Staphylococcus aureus (MRSA). Todays, herbal extracts like Zataria multiflora from Lamiaceae family are increasingly used. The aim of this study is the evaluation the antibacterial effect of Zataria Multiflora exteract on MRSA. 232 strains of Staphylococcus aureus were examined for isolation of MRSA strains. As a result, 75 out of 232 strains were identified as MRSA by oxacillin screening method. Consequently, the antibacterial effect of Zataria multiflora on 75 strains of MRSA was evaluated. The extract of Z.multiflora was prepared from dried leaves, using maceration method. The antibacterial activity of the extract with initial concentration of 200 µg/ml was determined by micro broth dilution method. It is showed that the minimum inhibitory concentration (MIC) is varied from 2-16 µg/ml for MRSA strains. It inhibited the growth of S.epidermidis, S.saprophyticus and methicillin sensitive S.aureus (MSSA), with approximately 8-16 µg/ml. The minimum bactericidal concentration (MBC) of the extract that could destroy 62.6% MRSA strains and the other examined bacteria was 512 µg/ml and more. It seems that Zataria multiflora extract could inhibit the growth of all of mentioned bacteria. The bactericidal effect of Zataria multiflora extract was less than its bacteriostatic effect.

Failure in the treatment of burn patients infected with Pseudomonas aeruginosa could happen as a result of the acquisition of antibiotic resistance, including carbapenems. The aim of the present study was to investigate the phenotypic and genotypic characteristics of the Pseudomonas aeruginosa strains, isolated from burn patients.Patients and During a 12 month period, in this cross-sectional study, two hundred seventy strains of Pseudomonas aeruginosa were isolated from the burn patients in Ghotbeddin Burn Hospital, Shiraz, Iran. Screening for the carbapenem resistance in the isolates was carried out by the E test method. Sensitivity patterns of metallo-β-lactamase (MβLs) producing strains of pseudomonas to eleven antibiotics were determined by the mentioned method. The epidemiological associations of these strains were determined by Pulsed-field gel electrophoresis (PFGE). Of the 270 strains, 60 (22.2%) were resistant to imipenem and meropenem, classified as MβLs producing. MβLs producing strains of pseudomonas were completely resistant to five tested antibiotics while their sensitivities to the three most effective antibiotics including ceftazidime, amikacin and ciprofloxacin were 23.4%, 6.7 % and 1.7%, respectively. In PFGE, 37 patterns from the genome of Pseudomonas aeruginosa were observed. Majority of the strains (43; 71.6%) exhibited more than 80% similarity, based on the drawn dendrogram. According to the results, none of the tested antibiotics is safe to prescribe. As PFGE revealed, a limited number of Pseudomonas aeruginosa types are predominant in the hospitals which infect the burn patients.

Nowadays, the presence of extended-spectrum β-lactamases (ESBLs) producing strains in Serratia genus causes the emergence of resistance to many antibiotics. So, the lack of proper diagnosis of ESBLs strains can lead to failure in the treatment. The objective of the present study was to investigate ESBLs production in Serratia strains isolated from the clinical blood samples in Shiraz, Iran. In this study, 39 Serratia strains isolated from the patients referred to Namazi Hospital, during a 2 year period were tested. The antimicrobial resistance of the isolates to 21 antibiotics was evaluated using Kirby-Bauer disk diffusion method. Combination disk method was used to determine the ESBL phenotype among the isolates. PCR was performed to investigate the presence of ESBL genes of SHV, OXA and TEM types. The lowest antibiotic resistance rates belonged to meropenem (7.69%) and imipenem (5.12%). Overall, positive ESBL phenotype was identified in 69% (n = 27) of the isolates, 70.37% (n = 19) for S. marcescens and 29.62% (n = 8) for S. liquefaciens. Results obtained by PCR showed that only 20.51% carried OXA gene and 15.38% carried SHV-1 gene. TEM gene was detected in none of the isolates. This study showed a high prevalence of the emerging ESBL producing strains among clinical isolates of Serratia that could lead to an increase in antibiotic resistance. However, ESBLs genes other than those tested here may be more responsible for the emergence of ESBL phenotype among Serratia clinical isolates in our region.

One of the most common nasocomial bacteria is methicillin resistant Staphylococcus aureus (MRSA). Today, herbal extracts like Zataria multiflora from the Lamiaceae family are increasingly used.. In this study, the antibacterial effect of Z. multiflora on 75 strains of was evaluated.. The strains of Staphylococcus aureus were examined for isolation of strains. 75 out of 232 strains were diagnosed as by oxacillin 6µg /mL screening method. The extracts of Z. multiflora were prepared from dried leaves using a maceration method. The antibacterial activity of the extract with initial concentration of 200 µg /mL was determined by the micro broth dilution method.. The obtained results showed that the minimum inhibitory concentration (MIC) varied from 2 to 16µg /mL for strains. It inhibited the growth of S. epidermidis, S. saprophyticus and methicillin sensitive S. aureus (MSSA) by about 8-16 µg/mL. The minimum bactericidal concentration (MBC) of the extract that could destroy 62.2% strains and the other examined bacteria was 512 µg /mL or more.. In conclusion, it seems that Z. multiflora extracts could inhibit the growth of all of the mentioned bacteria. We noticed that the bactericidal effect of Z. multiflora extracts was less than its bacteriostatic effects..

The emergence of extended-spectrum β-lactamase (ESBL)-producing Shigella spp. is of increasing clinical concern specially in children worldwide. The aim of this study was to investigate the occurrence of extended-spectrum β-lactamase producing Shigella spp. in Tehran, IranThe study includedall Shigella isolates recovered from pediatric patients aged less than 12 years admitted to a major pediatric hospital in Tehran, Iran, from 2008 to 2010. Bacterial identification, antimicrobial susceptibility testing, extended spectrum β-lactamases (ESBLs) screening and confirmatory testswere performed according to the standard guidelines. Conjugal transfer experiments and plasmid analysis were also carried out. Polymerase chain reaction and sequencing were used to identify the genetic determinants responsible for ESBL production. Fourout of 55Shigella isolates,includingthreeS.sonnei and one S. flexneri, showed an ESBL-positive phenotype.Plasmid transfer of the ESBL phenotype was successful for the S. flexneri isolate only. By PCR and sequencing, one S. sonneiisolatetested positive for the CMY-59 gene, while the other two S. sonneiand the S. flexneriisolatestested positive for the blaTEM-1 and blaCTX-M-15 genes. We found the prevalence of ESBL producing Shigella isolates was higher than detection rates observed in many other countries. Our finding raise concerns about the dissemination of ESBL among the strains of endemic S. sonnei throughout the country, because this species is now the most frequently isolated Shigella species in Iran and shigellosis by such strains in the community can pose a significant threat to patients and presents a challenge for disease management.

Because resistance to antifungal drugs is seen in patients, susceptibility testing of these drugs aids in choosing the appropriate drug and respective epidemiology. This study has investigated and compared susceptibility patterns of the Aspergillus specie sisolated from patients by the Clinical and Laboratory Standards Institute (CLSI) reference broth microdilution (MD) assay and Etest method. The minimum inhibitory concentrations (MICs) of various antifungal agents (amphotericin B, ketoconazole, itraconazole, and voriconazole) for 108 Aspergillus species isolated from patients were determined by CLSI M38-A broth MD and Etest. The isolates were obtained from clinical samples that included tissues, sputum, bronchoalveolar lavage, abdominal tap, and cerebrospinal fluid. As revealed by the MD method, 63.9% of the isolates were sensitive to amphotericin B and 36.1% were resistant.Etest revealed that 61.1% were sensitive to amphotericin B and 38.9% were resistant. As for ketoconazole, 108 isolates (100%) were shown to be sensitive through the MD method; while the Etest revealedan 88.9% sensitivity and 11.1% were resistant. All species were susceptible to voriconazole, according to both methods. The measure of agreement (Kappa Index) for these three drugs was satisfactory (≥0.6). According to the MD method, 69.4% of the species were susceptible to itraconazole, whereas 30.6% were not. For this drug, the Etest showed 86.1% susceptible and 13.9% resistant. Voriconazole was the most effective agent against isolates. Using RPMI agar, we found the Etest to behelpful, readily available, and easy to use for determining invitro susceptibilities of Aspergillus species to voriconazole, amphotericin B, ketoconazole, and itraconazole in the region of this study.

H. pylori is a urease positive organism, and this activity in a gastric biopsy could be considered as a proof of the presence of H. pylori. For the reasons of high price and difficult accessibility to the commercial CLO-test in Iran, we designed an affordable equivalent test with high specificity, accuracy and availability. Biopsy samples from 80 symptomatic patients with gastrointestinal problems were included in this study. The results of our in-house made rapid urease kit were compared with the commercial CLO-test up to 3 hours and 24 hours after inoculation of the biopsy samples. Culture results and gram staining were proposed as gold standard. Helicobacter pylori was isolated from 36 patients (45.0%) after cultivation of biopsy samples. After 3 hours, 33 (91.6%) cases of positive samples for H. pylori, showed urease positive reaction using both, in-house made and CLO-test kits. However, 2 (5.5%) cases showed urease reaction at 24 hours using both the kits. The specificity of 100% was determined for both, in-house made and commercial CLO-test kits after 3 hours. The sensitivity for both the kits was estimated at 97.1% after 3 hours. However, after 24 hours, sensitivity and specificity of 97.1% and 88.64% was estimated for the in-house and 97.2 % and 95.4% for the commercial CLO-test kits, respectively. Specificity and sensitivity of 100% and 97.1 % for up to 3 hours follow biopsy sampling, could be considered as an advantage for our in-house rapid urease kit. Moreover, the rapid urease agar media designed in our lab is cost-effective with adequate sensitivity and specificity levels for the detection of H. pylori, compared with the commercial CLO-test.

Urinary tract infections (UTIs), including cystitis and pyelonephritis, are the most common infectious diseases in childhood. Escherichia coli (E. coli) accounts for as much as 90% of the community-acquired and 50% of nosocomial UTIs. Therefore, identification of E. coli strains is important for both clinical and epidemiological implications. Understanding antibiotic resistance patterns and molecular characterization of plasmids and other genetic elements is also epidemiologically useful. To characterize uropathogenic strains of E. coli, we studied 96 E. coli strains recovered from urine samples of children aged l month to 14 years with community-acquired UTIs in Jahrom, Iran. We assessed virulence factors (VFs), drug sensitivities, and plasmid profiles. Drug sensitivities of the isolates were: 19.8% (ampicillin), 24% (trimethoprim-sulfamethoxazole), 29.2% (tetracycline), 75.5% (nalidixic acid), 80.4% (cefixime), 84.6% (gentamicin), 91.4% (ciprofloxacin), 96.8% (nitrofurantoin), 96.8% (amikacin) and 100% (imipenem). Totally, 76 isolates harbored plasmids with an average of 5.5 plasmids (range: 1 – 10) in each strain. Plasmid profiling distinguished 22 different E. coli genotypes in all isolates that ranged in similarity from 50% to 100%. PCR showed that the prevalence of virulence genes ranged from 15.62% for hly to 30.2% for pap. These data mandate local monitoring of drug resistance and its consideration in empirical therapy of E. coli infections. Plasmid analysis of representative E. coli isolates also demonstrates the presence of a wide range of plasmid sizes, with no consistent relationship between plasmid profiles and resistance phenotypes. Plasmid profiles distinguished more strains than did the antimicrobial susceptibility pattern.

Pseudomonas aeruginosa is an important life-threatening nosocomial pathogen and plays a prominent role in serious infections in burned patients. The current study was undertaken to characterize P. aeruginosa strains isolated from burned patients in Tehran, Iran. The study was conducted in a major burn center in Tehran, Iran in 2007. A total of seventy specimens obtained from different clinical origin with positive culture results for P. aeruginosa were included in the study. Antimicrobial susceptibility test was performed according to the standard CLSI guideline. The relationship between the strains was also determined using antimicrobial drug resistance pattern analysis and plasmid profiling. All strains were multi drug resistant. The percentage of resistance to tested antibiotics was: imipenem 97.5%, amikacin 90%, piperacillin 87.5%, ceftizoxime 72.7%, gentamicin 67.5%, ciprofloxacin 65%, ceftriaxone 60%, and ceftazidime 57.5%. Thirteen resistant phenotypes were recognized, R3 (TET, IPM, AMK, CIP, PIP, GM, CAZ, CRO, CT) was the predominant resistance pattern seen in 27.5% of isolates. Results obtained from E-test showed that 100% of P. aeruginosa strains were resistant to cefoxitin, 97% to cefotetan, 93% to ticarcillin, 89% to ticarcillin/clav, 76% to gentamicin and imipenem, 63% to piperacillin, 49% to tetracycline, and 20% to meropenem. Nine different plasmid profiles were observed among the strains. The current study showed an increase rate of resistance for some antibiotics tested among P. aeruginosa strains isolated from burned patients in Tehran. A combination of antibiotic susceptibility testing and profile plasmid analysis, which are relatively cheap and available methods, showed to be useful to characterize the clinical strains of P. aeruginosa isolated from burned patients in Iran.

Cholera has been a significant public health challenge in many communities. An outbreak of acute diarrheal illness occurred among participants in a wedding ceremony in a village in Qazvin, Iran, in 2008. We conducted an epidemiological, environmental and microbiological investigation to determine the causative agent, source and extent of this outbreak. Clinical and environmental samples were collected and analyzed for the presence of diarrhea-causing bacterial organisms, which included Vibrio cholera. The relationship between the strains was determined using enterobacterial repetitive intergenic consensus polymerase chain reaction (ERIC-PCR). The attack rate was 21.8%. Clinical and environmental samples were positive for V. cholerae serotype Inaba. All tested isolates had a similar ERIC-PCR pattern, which indicated that a single clone of V. cholerae was responsible for this outbreak. Our findings demonstrated that well water was the source of this outbreak.

Introduction. Escherichia coli are the most frequent pathogens in acute urinary infections. They are classified based on various types of O antigen. Escherichia coli strains that cause urinary tract infections possess several genes encoding urovirulent factors. To assay the relation of virulent factors of E coli in acute urinary infections, the serotypes and virulence factor genotypes were determined.Materials and Methods. We studied 96 E coli isolates from children with acute urinary infections. Four urovirulence determinants were analyzed by DNA colony hybridization, including the genes for type 1 fimbriae (pil), P fimbriae (pap), S fimbriae (sfa), hemolysin (hly), and cytotoxic necrotizing factor 1 (cnf1). O serotypes were also determined.Results. The most frequently found virulence factor-encoding gene in the E coli strains studied was the gene for type 1 fimbriae (27.4%). The prevalence of pap, sfa, hly, and cnf1 were higher in serotypes causing pyelonephritis than cystitis. The most common type of O antigen was O1 (12.2%). There was a significant correlation between serotype and genotype in uropathogenic E coli.Conclusions. The high prevalence of O6 serotypes in children urinary tract infections and the high percentage of virulent genes in serotype O6 suggested a close relation between serotype and genotypes of uropathogen E coli.

Shigellosis is one of the major causes of morbidity in children with diarrhea in Iran. Integrons play an important role in the evolution and dissemination of multidrug resistance in gram-negative bacteria. The occurrence of integrons among Shigella spp. is frequently reported throughout the world. The aim of this study was to assess the occurrence of class 2 integrons among the multi drug resistant S. sonnei isolated from Iranian children in 2005. The study was conducted in two major pediatric hospitals in Tehran, Iran. Fecal specimens and rectal swab collected from patients were cultured and identified as Shigella by the conventional methods. Antimicrobial susceptibility test was performed according to the standard CLSI guideline. Multi-drug resistant isolates of S. sonnei were further examined for the presence of class 2 integron by PCR using specific primers. Amplicons were confirmed by restriction endonuclease analysis. A total of 83 multi-drug resistant S. sonnei strains were isolated. Of these, 45 (54%) exhibited a class 2 integron of 2.1 kbp, and 34 (41%) a class 2 integron of 1.3 kbp. Class 2 integrons were not detected in four isolates. The results showed an increased occurrence of class 2 integron carrying S. sonnei isolated from children in Tehran in 2005.

The prevalence of Helicobacter pylori has declined rapidly in Asia. This has been shown in both seroprevalence-based and endoscopy-based studies. The present study was conducted to determine the prevalence of gastric infection caused by H. pylori in an Iranian population residing in south of Iran.Patients and A total of 522 patients (266 females and 256 males with the mean age of 44.3±13.0, range 18-83 years) underwent endoscopy in Shiraz, southern Iran. The diagnosis of H. pylori infection was established by rapid urease test, culture and gram staining and the gastric disease was confirmed by an expert pathologist. From ulcerative (n=296) and non-ulcerative (n=226) patients, 156 (52.7%) and 94 (41.6%) H. pylori strains were isolated by culture, respectively. The prevalence of H. pylori infection was significantly higher in patients aged 21-30 and >50 years (66.66% and 62.12%, respectively). However, H. pylori was not detected in 22 patients aged

Previous studies imply that IL-1 and IL-8 gene variations may play a crucial role in the genetic predisposition to different gastric disorders upon H. pylori infection. The aim of this study was to determine the potential association between the prevalence of certain polymorphic sites and the risk of gastric disorders inIranian population. One hundred and forty three unrelated individuals withdifferent gastric disorders and 374 normal individuals with no gastric disorders and witha negative serology test for H. pylori (control group) were studied for the associationbetween IL-1β (+3953 C/T) and IL-8 (-251 A/T) gene polymorphisms and H. pylorimediated gastritis and gastric ulcer. An analysis of genotype frequency for these genes was performed using RFLP-PCR. Based on the data obtained from culture and pathologic findings, the patients were classified into three subpopulations: H pylori+non-ulcerative gastritis+, H. pylori+ ulcerative gastritis+ and H. pylori- non-ulcerativegastritis+. A significantly higher frequency of TT genotype (p=0.02) in IL-1β +3953 inH. pylori+ ulcerative gastritis+ was revealed compared to the control group. There wereno significant differences among other subpopulations. No significant differences in alleleand genotype frequencies of IL-8 (-251A/T) were found among the patients. The data suggest that TT genotype in IL-1β +3953 may be a major contributing genetic risk factor for H. pylori induced gastric ulcer. Moreover, the role of other bacterial and host response factors, such as bacterial adherence peptides, host chemokines, and genes involved in gastric acid secretion, must be further investigated in different ethnic populations.

Shigellosis as a global human health problem is more severe than other forms of gastroenteritis and causes over a million deaths in developing countries worldwide annually. Fatality due to shigellosis is usually due to dehydration and two-third of fatalities are seen among children. The aim of current study was to describe fatal cases of shigellosis due to infection with Shigella sonnei and S. flexneri. Patients and We investigated the fatal cases of shigellosis among all children with acute diarrhea admitted to Children’s Medical Center, Tehran, Iran. Bacterial isolation and identification was achieved according to standard bacteriological methods. Antibiotic susceptibility tests, plasmid profiling and ribotyping were performed to investigate the clonal relationship among the isolates. Among 1200 children with acute diarrhea, 140(12.7%) cases had shigellosis. Of these, three patients died. No signs of severe dehydration were observed among the fatal cases. The symptoms were not improved following antibiotic therapy and all three cases died after 24 h of hospitalization despite receiving intensive treatments. Stool cultures yielded S. flexneri and S. sonnei for one and two cases, respectively. The isolates were resistant to streptomycin, ampicillin, and sulfamethoxazole-trimethoprim. S. sonnei strains were further studied and showed a single pattern of antibiotic susceptibility and ribotyping. Mortality due to species other than S. dysenteriae is rare, however, in current study we found S. sonnei and S. flexneri as the cause of fatality among pediatric patients during the study.

Infections caused by Shigella are a major cause of diarrheal disease in the developing and developed countries. The present study was conducted to apply and evaluate arbitrarily primed PCR (AP-PCR) for investigation of genetic relatedness among the strains of Shigella sonnei isolated from cases of acute diarrhea in Tehran.Patients and Totally, 60 S. sonnei strains isolated from children hospitalized due to enteritis at five hospitals in Tehran during 2003 and two sporadic isolates recovered in 1984 were investigated. Molecular typing was performed by AP–PCR. Depending on the number and size of amplified DNA bands, the strains were clustered into AP–PCR profiles. All strains of S. sonnei were typeable with this approach. AP–PCR generated nine indistinguishable bands ranged from 0.35 to 2.5 kbp in all studied strains. Only a single AP-PCR pattern was observed among the S. sonnei strains recovered in 2003. Two sporadic isolates recovered in 1984 showed different AP-PCR patterns compared to recent clinical isolates. Results suggest that a very homogeneous AP-PCR cluster types might be responsible for shigellosis caused by S. sonnei in Tehran in 2003. Further molecular analysis conducted on a larger selection of isolates could confirm our findings

Nowadays E.coli the most common Cause of acute urinary tract in fection are generally named based on serotypes of O and H. The aim of this Cross-Sectional study, was to determine the prevalence of H serogroups of E. coli strains that cause community acquired UTI in children. Methods and materials: In this study 96 children with urinary tract infections (UTI) referred to two teaching Hospitals, in Jahrom, Iran during the period of August 2005- August 2006 were enrolled. Antibiogram was done by disk diffusion method and serotyping by tube and slide agglutination methods. A Total of 96 E. coli strains were isolated from the urine samples of children with UTI aged from one month to 14 years. Cystitis was diagnosed in 49.2% and pyelonephritis in 50.8% of these patients. The most resistance was related to Ampicilin (80.2%) and the least to imipenem (1.1%). The most common type of H antigen was H4 (6.1%). This is the first report of E-coli serotying in children with UTI from the south of Iran and its relation ship with antibiotic resistance and clinical presentation. Funthen reoeach in athes p ts with move st e thypes is re Commended.

It is not clear what factors determine divergent outcomes of infections caused by H. pylori. In the present study, the protein profiles of different strains of H. pylori, isolated from three groups of patients with ulcerative disease, non-ulcerative gastritis and cancer disease, were analyzed using 1D-SDS-PAGE. The patterns of different H. pylori strains were highly divergent. About 30.76% (7 bands) of the 26 observed protein bands were common in all strains isolated from 3 groups of the patients. While the similarity for the strains inside each group were 75% (15 from 20), 76.47% (13 from 17) and 78.57% (11 from 14) for cancerous, ulcerative and nonulcerative group, respectively. Some of the observed bands were significantly specific for each group. Therefore, we speculated that some H. pylori strains might be more associated with a specific disease than others, giving the clustering of some, but not all, strains within each disease group. In conclusion, this study showed that protein profile can be a characteristic in discrimination of dominant strains in different gastric clinical status. Specific and dominant proteins of different strains isolated from three groups of patients under study were candidates for further exploration for laboratory tests, which analyze disease-specific H. pylori strains, and for diagnosis of the different diseases and outcomes associated with this widespread bacterium. Iran. Biomed.

There is a growing concern about the application of molecular methods in epidemiological studies of infectious diseases. The objective of this study was to determine the genetic stability of methicillin resistance genes in Staphylococcus aureus for the evaluation of resistance strain distribution. One hundred and fifteen S. aureus isolates from patients with staphylococcal infection were collected. The isolates were screened for methicillin resistance by minimum inhibitory concentration (MIC) examination. The stability of methcillin resistance genes was examined by physical curing and PCR screening methods. The results showed that methicillin resistance Staphylococcus aureus (MRSA) had risen up to 43% in Nemazi Hospital (Shiraz, Iran). Indeed, the incidence of MRSA in our hospital was 10% during the last four years. The ability to lose (curability) of methicillin resistance genes (mecA) was examined by physical curing method in 49 isolates with MIC ³ 16 μg ml-1. No sign of curability of mecA gene was observed where 500 colonies from each strain have been studied and exhibited by the same MIC values before and after curing test. Positive PCR results for isolates with MIC ³ 16 μg ml-1 before and after curing experiment have been achieved. These data confirm the results of curing method, indicating that stable genetic determinants confer methicillin resistance. These results support the hypothesis that resistance isolates may be selected due to clonal selection under antibiotic pressure used in clinics rather than transmission of mobile genetic determinant. The high prevalence of MRSA immerged in our Hospital could be originated due to antibiotic pressure and poor control measures.

In order to improve simultaneous detection and identification of Helicobacter genus in general and Helicobacter pylori specifically and reduce the number of amplifications needed, we established a multiplex PCR. In this study, two pairs of primers: Hcom1 and Hcom2 specific for Helicobacter genus, Hicd1 and Hicd2 specific for Helicobacter pylori species were used. To determine the sensitivity of our multiplex PCR, the lower limits of DNA detection from pure culture were established using phenol-chloroform method. To evaluate the specificity of our protocol, we tested DNA extracted from various Gram-negative and -positive bacteria. A study was subsequently undertaken on stomach tissue samples from 18 patients to evaluate this protocol for detection of Helicobacter in tissue samples. In our optimized PCR, two fragments of 389- and 1200-bp were produced using Hcom1-Hcom2 and Hicd1-Hicd2 primers, respectively. Amplification of Helicobacter pylori genomic DNA was achieved at concentration as low as 0.03 pg equivalent to 150 bacteria. No DNA amplification of other Gram- positive and -negative bacteria was seen. Twelve specimens, positive in culture and rapid urease test for Helicobacter pylori were positive for DNA of this organism using this multiplex PCR. Our results demonstrate that this protocol represents a specific and sensitive assay for simultaneous detection of Helicobacter genus members, in general, and Helicobacter pylori species, specifically, in clinical samples yielding no false-positive