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Background:Tatumella ptyseos is a rod-shaped, Gram-negative, facultative, and anaerobic bacteria categorized in the Enterobacteriaceae family. It is a rare food-borne opportunistic pathogen which causes neonatal sepsis, bacteremia, and urinary tract infections. T. ptyseos has been also cultured from various food sources around the world.Objectives:It is difficult to determine the source of the infection in the patients (especially newborns) due to low information about the epidemiology of T. ptyseos. The current study aimed to investigate the isolation, identification and antimicrobial susceptibility pattern of T. ptyseos strains from the consumed powdered infant formula milk (PIF) in hospital neonatal intensive care unit (NICU).Materials and Methods:A total of 125 powdered infant formula milk (PIF) samples were purchased from drug stores from June 2011 to March 2012. T. ptyseos was isolated according to food and drug administration (FDA) method. For final confirmation, biochemical testes embedded in API-20E system were used. Drug susceptibility test was performed using the disc diffusion method, according to clinical and laboratory standard institute (CLSI) recommendations.Results:Results of the study showed that, out of 125 samples, T. ptyseos was isolated from four (3/2%) PIF samples. All isolated strains (100%) were resistant to ampicillin, carbenicillin, cotrimoxazole and amoxicillin.Conclusions:The present study was the first report on the isolation and identification of T. ptyseos from PIF in Iran. T. ptyseos are frequently present in various kinds of foods; therefore, further investigation on these samples is required. It is necessary to track the T. ptyseos in a wide variety of foods and individuals especially in immunocompromised people such as human immunodeficiency virus (HIV)-positive patients to reveal the possible routes of transmission of this pathogen to humans. In addition, molecular studies are required to determine the genetic relationship between T. ptyseos strains isolated from different sources.

ObjectivesThe genus Shigella comprises the most infectious and diarrheagenic bacteria causing severe diseases, mostly in children under five years of age. This study aimed to detect nine virulence genes (ipaBCD, VirA, sen, set1A, set1B, ial, ipaH, stx, and sat) in Shigella species (spp.) using multiplex polymerase chain reaction (MPCR) and to determine the relation of Shigella spp. from pediatric diarrheal samples with hospitalization and bloody diarrhea in Tehran, Iran.MethodsShigella spp. were isolated and identified using standard microbiological and serological methods. The virulence genes were detected using MPCR.ResultsSeventy-five Shigella spp. (40 S. sonnei, 33 S. flexneri, 1 S. dysenteriae, and 1 S. boydii) were isolated in this study. The prevalence of ial, sen, sat, set1A, and set1B was 74.7%, 45.4%, 28%, 24%, and 24%, respectively. All S. flexneri isolates, while no S. sonnei, S. dysenteriae, or S. boydii isolates, contained sat, set1A, and set1B. All isolates were positive for ipaH, ipaBCD, and virA, while one (1.4%) of the isolates contained stx. The highest prevalence of virulence determinants was found in S. flexneri serotype IIa. Nineteen (57.6%) of 33 S. flexneri isolates were positive for ipaBCD, ipaH, virA, ial, and sat. The sen determinants were found to be statistically significantly associated with hospitalization and bloody diarrhea (p = 0.001).ConclusionThis study revealed a high prevalence of enterotoxin genes in S. flexneri, especially in serotype 2a, and has presented relations between a few clinical features of shigellosis and numerous virulence determinants of clinical isolates of Shigella spp.

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Background:Barrett’s oesophagus is a pre-malignant condition at gastroesophageal junction in which normal squamous epithelium is replaced by columnar shape epithelium, which predisposes oesophageal adenocarcinoma. It is known that Barrett’s oesophagus evolves as a consequence of chronic gastro-oesophageal reflux disease. Although progression of Barrett’s oesophagus to adenocarcinoma is still unclear, increasing incidence of oesophageal cancer and mortality worldwide make its study necessary. Several investigations have been made on the aetiology of oesophageal cancer. Most of them assessed genetical or environmental factors. However, potential role of bacteria in the development of oesophageal adenocarcinoma as a new environmental factor has not been addressed. Previous study on Barrett’s disease detected presence of Campylobacter concisus as a new emerging pathogen on Barrett’s and oesophageal cancer samples compared with healthy individuals. This indicates that this organism might involve in the progression of Barrett’s to oesophageal adenocarcinoma.Objectives:This study aimed to determine the effects of C. concisus on expression of three biomarkers including interleukin-18 (IL-18), tumour necrosis factor-α (TNF-α) and tumour suppressor gene (p53) in three Barrett's cell lines.Materials and Methods:Quantitative real-time PCR assays were developed to measure expression of pro-inflammatory mediators (IL-18 and TNF-α) and gene expression of p53 in Barrett's cell lines in co-culture with C. concisus.Results:The mentioned organism was able to modulate considerably expression of p53, TNF-α and IL-18 in a time-dependent manner.Conclusions:The results showed that microorganism influences expression of carcinogenesis biomarker and cytokines in cell line models and possibility promotes oesophageal adenocarcinoma.

Background:Among the enteric pathogens, diarrheagenic Escherichia coli are important causes of diarrhea in children in both developing and industrialized countries. Some Lactobacillus species are commonly used as probiotics, with effects especially against acute diarrhea in childhood.Objectives:The aim of this study was to explore antimicrobial activity of Lactobacillus strains isolated from fecal flora of healthy breast-fed infants against five diarrheagenic E. coli pathotypes such as enteroaggregative E. coli (EAEC), enterohaemorrhagic E. coli (EHEC) enteroinvasive E. coli (EIEC), enteropathogenic E. coli (EPEC) and enterotoxigenic E. coli (ETEC).Materials and Methods:Fecal samples were collected from seven healthy breast-fed infants between 1 to 18 months of age in Tehran city, Iran. Identification of Lactobacillus isolates was performed by biochemical and 16S rRNA gene sequencing methods. An agar well diffusion assay was used for detection of antimicrobial activity of Lactobacillus isolates against five diarrheagenic E. coli pathotypes.Results:A total of 20 Lactobacillus isolates were identified from stool samples. Lactobacillus fermentum was the most frequently isolated strain, followed by L. plantarum and L. rhamnosus. Seven Lactobacillus strains including L. fermentum (four isolates), L. paracasei (one isolate), L. plantarum (one isolate) and L. rhamnosus (one isolate) had a mild inhibitory activity against diarrheagenic E. coli. The mechanism of inhibitory activity of Lactobacillus strains appeared to be due to the production of organic acids or hydrogen peroxide.Conclusions:Our findings show that Lactobacillus strains with human origin had a mild inhibitory activity against the diarrheagenic E. coli, and these strains may be useful as probiotic candidates in prevention of intestinal infections caused by diarrheagenic E. coli.