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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.

Background: Infections are considered as one of the main factors of neonatal mortality, especially in developing countries. Blood and urine infections are one of the most prevalent infectious factors among the infants. On the other hand, resistance against antimicrobial factors is one of the major problems in the world, and it is important to be informed about antibiotic resistance pattern of microorganisms for treatment of infections., Objectives: The aim of this study was to examine the bacterial strains causing blood and urinary tract infections in Neonatal Intensive Care Unit (NICU) and determine their antibiotic resistance pattern., Materials and Methods: In this study, the microorganisms of 150 blood and urine samples of infants hospitalized in NICUs of Imam Hussein Hospital, Children Hospital Center and Bahrami Hospital in Tehran, Iran, were collected during seven months, and the antimicrobial resistance patterns of the isolates were studied by the Kirby-Bauer test., Results: During the seven-month study on 105 samples, including 85 (81%) urine samples and 20 (19%) blood samples, 81 samples (77.1%) were Gram-negative and 24 (22.9%) were Gram-positive organisms. Klebsiella pneumoniae (30.5%) was the most common Gram-negative microorganisms and Staphylococcus epidermidis (11.4%) was the most prevalent Gram-positive microorganisms. The most antimicrobial susceptibility in Gram-negative microorganisms was shown to ciprofloxacin (84.2%) and in Gram- positive ones was shown to vancomycin (83.3%)., Conclusions: This results of the study show that the most contamination in NICUs is from Gram-negative bacteria and ciprofloxacin is the most effective antibiotic for treatment. Thus, the control of infections in NICUs in hospitals is very important.

Background: The immunomodulative effects of Lactic Acid Bacteria as probiotics have been already demonstrated., Objectives: The current study aimed to evaluate the effect of oral administration of Lactobacillus acidophilus on the immune responses and patterns of cytokine production in the BALB/c mice bearing breast cancer., Materials and Methods: The current study used thirty inbred BALB/c mice, six- to eight-week-old; they were divided into two groups of 15 each. One group was used as control in each assay. The L. acidophilus (ATCC4356) used in the study was inoculated in MRS broth and cultivated overnight at 37°C under anaerobic conditions, then collected by centrifugation, and re-suspended in Phosphate-buffered Saline (PBS) media. After preparation of the proper amount of the suspension, it was orally administered to the mice via gavage and the control mice received an equal volume of PBS in the same manner., Results: The results showed that oral administration of L. acidophilus as a potent immunostimulator agent could motivate the proliferation of immune cells. Moreover, it could increase the production of IFN-γ and decrease the production of IL-4, known as Th2 cytokines, in the spleen cell culture. The results showed that the survival time of the L. acidophilus administered mice significantly increased in comparison to that of the control mice., Conclusions: The current study findings suggested that L. acidophilus can promote immune responses with Th1 bias and may increase the antitumor response. Further, the consumption of this probiotic strain may help to manage the immune response in tumor condition, but more studies are needed to investigate the other mechanisms of this effect.

Objective: Enterobacter cowanii is a genus of common gram-negative, facultatively anaerobic, rod-shaped, non-spore-forming bacterium of the Enterobacteriaceae family. This organism can be potentially a powdered infant milk formula-borne opportunistic pathogen. The aim of this study was to isolate and identify E. cowanii from consumed powdered infant formula milk (PIF) in intensive care units (NICU) and to determine antimicrobial susceptibility patterns of this bacterium., Methods: E. cowanii was isolated according to FDA method in 125 samples of PIF milk purchased from drug stores between Jun 2011 and March 2012. For final confirmation, biochemical tests embedded in API-20E system were used. The drug susceptibility test was performed using the disc diffusion method according to CLSI recommendations. Findings : Out of the 125 PIF samples investigated, 4 (3.2%) samples were positive for E. cowanii. All four isolates from PIF samples were uniformly susceptible to imipenem, meropenem, ceftazidime, ciprofloxacin, and colistin. Fifty percent of isolates were resistant to ampicillin, amoxicillin, and cotrimoxazole Conclusion: Analysis of the results indicated that complementary studies are necessary to clarify the possible role of E. cowanii as a food contaminant, in common NICU infections and high risk groups including persons with underlying disease and immunocompromised individuals.

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.

Background: Despite of the advances in infectious diseases prevention and food technology, food-borne diseases are considered major problems in developed and developing countries. Meat plays a key role in transferring zoonotic diseases to human., Objectives: This study was conducted in south of Tehran, Iran, to investigate the prevalence rate of Salmonella spp. in packed and unpacked red meat and chicken., Materials and Methods: A total of 379 packed and unpacked samples including 189 red meat and 190 chicken samples were collected randomly. From each sample, 25 g was separated and treated with 225 mL of buffered peptone water, homogenized and incubated at 37°C for 24 hours. Samples were enriched using Rappaport-Vassiliadis broth and then streaked onto Hektoen enteric agar., Results: Totally, 86 out of 190 chicken and 38 out of 189 red meat samples were contaminated with Salmonella spp. The most isolated serotypes were Salmonella thompson (67.7%), S. heaardt (6.5%), S. enteritidis (4.8%), and S. veyle (4%), respectively. In general, the rate of chicken contamination was higher than meat, as 43.3% of packed and 46% of unpacked chicken samples were contaminated., Conclusions: These results confirmed the pervious findings, stating that proper packaging of meat products can effectively decreases the rate of microbial contaminations.

Background: Treatment of infectious diseases is becoming more challenging with each passing year. This is especially true for infections caused by Pseudomonas aeruginosa, an opportunistic pathogen with the ability to rapidly develop resistance to multiple classes of antibiotics., Objectives: This study was conducted to determine the prevalence of metallo-β-lactamase (MBL)-producing strains among multidrug-resistant P. aeruginosa strains isolated from burn patients., Materials and Methods: The isolates were identified, tested for susceptibility to various antimicrobial agents, and screened for the presence of MβLs by using the double-disk synergy test. The minimal inhibitory concentration of imipenem was determined by microplate broth dilution method on Mueller-Hinton agar. To detect VIM, SIM, and GIM MBLs, the isolates were subjected to polymerase chain reaction., Results: In this study, we identified 100 P. aeruginosa isolates from 176 clinical specimens obtained from burn patients. The isolates showed maximum resistance to ampicillin (100%), ceftazidime (94%), and ceftriaxone (89%). The CLSI-MBL phenotypic test showed that of the 100 P. aeruginosa isolates, 22 (22%) were positive for MBL production in the double-disk synergy test. Of the 22 MBL-positive P. aeruginosa isolates, 8 were resistant to imipenem. PCR analysis showed that 8 isolates were positive for blaVIM1. The other genes blaSIM1 and blaGIM1 were not detected., Conclusions: The study results demonstrate the serious therapeutic threat of the spread of MBL producers among P. aeruginosa populations. Metallo-β-lactamases were detected in 22% of imipenem-resistant P. aeruginosa isolates. Early detection and infection-control practices are the best antimicrobial strategies for this organism; therefore, systematic surveillance to detect MBL producers is necessary.