Sequence diversity in tRNA gene locus A-L among Iranian isolates of entamoeba dispar

A number of methods for detecting diversity in Entamoeba have been described over the years. In the present study the genetic polymorphism of noncoding locus A-L was analyzed using PCR and sequencing in order to clarify the genotypic differences among E. dispar isolates. A total of 28 E. dispar from patients with gastrointestinal symptoms were determined and the genomic DNA was extracted directly from stool. For genotype analysis; Locus A-L was amplified by PCR and PCR products were sequenced .The sequences obtained were edited manually and aligned using Gene Runner software. With sequencing of PCR products a reliable genetic diversity in size, number and position of the repeat units were observed among the Iranian E. dispar isolates in locus A-L gene. Sequences showed variation in length from 448bp to 507bp and seven distinct types were identified. The genetic diversity of loci like A-L shows them to be suitable for epidemiological studies such as the characterization of the routes of transmission of these parasites in Iran

[Prevalence and antimicrobial resistance pattern of thermophilic Campylobacter spp. [jejuni and coli] isolated from beef and raw chicken in Tehran]

Microbial food safety and food borne pathogens with antibiotic resistance or multidrug resistance is an increasing public health concern worldwide. Campylobacter is one of the most common causes of acute bacterial gastroenteritis in human, especially in children. The objects of our study were to determine the frequency and antibiotic resistance pattern of thermopilic Campylobacter spp. [jejuni and coli] in raw poultry and beef isolates. The samples of raw chicken and beef [packaged and non-packaged] were purchased from the different parts of Tehran and then transferred to laboratory. Specimens were enriched in Preston Broth and cultured on Campylobacter selective agar medium for 48h. After that, suspected colonies isolated and confirmed by standard tests. Antimicrobial sensitivity was carried out using disk diffusion method. Out of 379 samples, Campylobacter spp was identified in 109 [28.8%] cases comprising of C.jejuni [76.1%] and C.coli [23.9%]. The rate of isolation from chicken [49.7%] was more than that of beef [7.9%]. There was a significant correlation between the rate of contamination by Campylobacter and type of meat [P<0.05]. 41.8% of packaged and 54.1% of non-packaged [P value = 0.197] chicken samples and 4.5% of packaged and 9.8% of non -packaged beef samples [P value = 0.105] were contaminated with Campylobacter. Among the variety of tested antibiotics, the highest resistance was found for Nalidixic acid [71%] and Ciprofloxacin [46.7%]. None of the strains were observed to be resistant to Gentamicin. The high prevalence of Campylobacter jejuni contamination in chicken meat represents the absence of hygiene rules in slaughtering the poultries and transferring process. Isolated strains from meat show increasing susceptibility against Fluroquinolone. The reason of susceptibility increment in isolated Campylobacter strains could be misusage of consumption of antibiotics such as Enrofloxcin in chicken farms. Sensitivity to Gentamicin makes this drug a suitable alternative for treatment of Campylobacter infection

Genetic diversity among entamoeba histolytica and entamoeba dispar strains in gastrointestinal disorder patients in Tehran, Iran

Since the first description of Amebiasis, we still do not have a proper answer to the question of why disease and symptoms develop in only 5 to 10% of those infected with E. histolytica. It has been speculated that a spectrum of virulence levels among the E. histolytica strains contribute to the outcome of amebic infection. In this study, beside determination of prevalence rate of E.histolytica and E.dispar in gastrointestinal disorder patients, genetic diversity in non-coding locus 1-2 was investigated to identify genetic differentiation of Entamoeba in positive isolates. A total of 1700 stool samples were checked from patients referred to clinical laboratories affiliated with Shahid Beheshti Medical University; samples were examined by direct and formalin detergent methods. Twenty seven cases of E. histolytica/E. dispar were detected and total genomic DNA was extracted from stool samples. E. histolytica/E. dispar complex were determined by PCR with two sets of species-specific primers from locus 1-2 gene. The purified PCR products were sequenced and the results were compared with known E. histolytica and E. dispar sequenced data. PCR for locus 1-2 gene amplified a fragment of about 430 bp in 21 out of 27 samples and was identified as E. dispar. One isolate showed a band of about 340 bp and was identified as E. histolytica. PCR were negative in five samples which were discarded. With PCR and sequencing of the PCR products a reliable genetic diversity in size, number and position of the repeat units were seen among the Iranian E. dispar isolates in locus 1-2 gene. Eight new E. dispar genotypes were found in this study and submitted to the Gen Bank/EMBL/DDBJ. The only Iranian E. histolytica isolate [NH1 E.h IR] was completely similar with the KU2 [Accession No. AB075706] strain reported from Japan