ABSTRACT
Background: A few reports confirm the ability of Helicobacter pylori to form biofilm. However, conclusive data do not exist concerning the factors that favor this ability
Objectives: Evaluation of the factors associated with the biofilm formation ability of H. pylori including bacterial, physical and chemical, and environmental factors was the research's aim
Materials and Methods: H. pylori isolates from gastric biopsy specimens of patients infected chronically were screened for biofilm formation ability. Association of bacterial properties such as motility, auto-aggregation, cell hydrophobicity, and extracellular polymeric substances [EPS] with in vitro biofilm formation ability of H. pylori was evaluated. The effects of environmental factors such as growth-medium, temperature, oxygen-tension, pH, beta-cyclodextrin, gastric secreted mucins, and sub-inhibitory concentration of amoxicillin were also evaluated
Results: Ability of clinical H. pylori isolates to form biofilm in was quantitatively compared. The coccoid shape H. pylori cells were observed by scanning electron microscopy, the images were illustrative of the attachment of cells to form microcolony. The levels of hydrophobicity, motility and auto aggregation of two isolates with highest and lowest biofilm formation ability were the same. However, the significant role of mucins [P < 0.05] in elevating the biofilm formation was observed. Other factors influencing biofilm formation were: pH, atmosphere and sub-MIC of antibiotics
Conclusion: Mucins have a significant role in elevating the biofilm formation, also pH, atmosphere and sub-MIC of antibiotics influence biofilm formation
Subject(s)
Humans , Helicobacter pylori/isolation & purification , MucinsABSTRACT
Aim: The purpose of this study was to find the isolation rate of enteropathogenic Escherichia coli [EPEC] from lettuce samples collected in Tehran
Background: During the last decade, the prevalence of infectious diarrheal diseases due to consumption of contaminated food especially raw vegetable has been increasingly reported. Enteropathogenic Escherichia coli strains are an important group of diarrheagenic E. coli that can cause infant diarrhea especially in the developing world
Material and Methods: One hundred lettuce samples collected in Tehran were transported to the laboratory, homogenized by a stomacher in EC broth containing cefixime, and cultured on MacConkey agar plates. Bacterial DNA was extracted by boiling method and PCR was performed using three pairs of primers targeting stx1, stx2 and eaeA genes
Results: Screening of 100 lettuce samples by PCR showed four samples were positive for the presence of EPEC
Conclusion: This study suggests contamination of the lettuce by the EPEC and its possible role as the source of infection in this region
ABSTRACT
Outer inflammatory protein A [OipA] is one of the important adhesins of H. pylori and a valuable candidate for vaccine development. Its gene is under "on-off" switch status which correlates with OipA protein expression. We aimed to obtain a recombinant OipA clone [with "on" status] from an Iranian clinical isolate. A clinical H. pylori-isolate demonstrating high expression for an outer membrane protein [OMP] with an apparent MW of 33-35 kDa was selected. oipA specific primer was designed according to oipA sequences from B8 strain. The purified PCR-product was sequenced and submitted to Gene Bank. The pET-28a plasmid and E. coli DH5alpha were used for cloning and transformation. The recombinant plasmid was transferred to E. coli BL21 [DE3]. Extracted proteins were purified and presence of OipA was confirmed by western blotting using both anti His-tag monoclonal antibody and anti-OipA specific antibody. The sequence of the oipA gene and the MW of the purified recombinant OipA protein consisted on 924 bp and 33-35 kDa, respectively. Its identity with other published oipA genes was 92-96%; highest identity was observed with that of a Mexican oipA clone, obtained from a H. pylori strain associated with severe symptoms. Recombinant oipA clone obtained in this work, may be a functional oipA gene with "on" status, associated with more severe outcomes of H, pylori infection