Adhesion and virulence factor properties of Enterococci isolated from clinical samples in Iran.

Introduction: Enterococci rank among leading causes of nosocomial bacteremia, urinary tract infections and community acquired endocarditis. The aim of the present study was to investigate the presence of virulence factors in Enterococci strains isolated from clinical samples in Iranian Educational hospitals. Methodology: Presence of aggregation substance (asa), extracellular surface protein (esp), Enterococcus faecalis antigen A (efaA), adhesin of collagen from E. faecalis (ace), endocarditis and biofi lm-associated pilli (ebp) as colonization factors and cytolysin (cyl), gelatinase (gel) and hyaloronidase (hyl) as secretary factors were investigated in isolates. A total of 201 clinical isolates of Enterococci were collected in 2009-2010 from eight educational hospitals. After deoxyribonucleic acid extraction, they were examined for presence of virulence factors by polymerase chain reaction. Results: E. faecalis and Enterococcus faecium were isolated from 56.9% to 43.1%, respectively. Resistance to vancomycin and gentamicin were 33.8% and 83.9% in E. faecium isolates and 16.3% and 88.1% in E. faecalis isolates respectively. Colonization factors were found to be more prevalent in E. faecalis isolates and almost all isolates of E. faecalis had ace, ebp and efaA genes. Esp gene had a higher rate of distribution in Enterococci isolates (75.1%) in this study compared with previous studies. One of E. faecalis isolates contained hyl gene, but 38.8% of E. faecium isolates had it. Mutual exclusive were present between hyl and efaA in all E. faecium isolates and 69.7% of E. faecium hyl - positive isolates were esp positive. Conclusion: According to these results, virulence genes were more prevalent in E. faecalis isolates and E. faecalis had more potential pathogenesis for initiating an infection; however because of E. faeciums higher antibiotic resistance, we have been facing higher E. faecium infections in hospitalized patients.

In silico experiment with an-antigen-toll like receptor-5 agonist fusion construct for immunogenic application to Helicobacter pylori.

BACKGROUNDS: Helicobacter pylori colonize the gastric mucosa of half of the world's population. Although it is classified as a definitive type I carcinogen by World Health Organization, there is no effective vaccine against this bacterium. H. pylori evade the host immune response by avoiding toll-like detection, such as detection via toll-like receptor-5 (TLR-5). Thus, a chimeric construct consisting of selected epitopes from virulence factors that is incorporated into a TLR-5 ligand (Pseudomonas flagellin) could result in more potent innate and adaptive immune responses. MATERIALS AND METHODS: Based on the histocompatibility antigens of BALB/c mice, in silico techniques were used to select several fragments from H. pylori virulence factors with a high density of B- and T-cell epitopes. RESULTS: These segments consist of cytotoxin-associated geneA (residue 162-283), neutrophil activating protein (residue 30-135) and outer inflammatory protein A (residue 155-268). The secondary and tertiary structure of the chimeric constructs and other bioinformatics analyses such as stability, solubility, and antigenicity were performed. The chimeric construct containing antigenic segments of H. pylori proteins was fused with the D3 domain of Pseudomonas flagellin. This recombinant chimeric gene was optimized for expression in Escherichia coli. The in silico results showed that the conserved C- and N-terminal domains of flagellin and the antigenicity of selected fragments were retained. DISCUSSION: In silico analysis showed that Pseudomonas flagellin is a suitable platform for incorporation of an antigenic construct from H. pylori. This strategy may be an effective tool for the control of H. pylori and other persistent infections.

Colonization of hospital water systems by Legionella pneumophila, Pseudomonas aeroginosa, and Acinetobacter in ICU wards of Tehran hospitals.

Background: Nosocomial infection caused by non-Enterobacteriaceae gram negative bacteria (GNB-NE) is increasing in intensive care units (ICU). Aim: The objective of this study was to determine whether potable water in ICU wards at Tehran hospitals is contaminated with L. pneomophila, P. aeroginosa and Acinetobacter spp. Materials and Methods: A total of 52 water samples from shower bath and taps water in seven hospitals of Tehran were collected. The water sample concentrated by filtering through millipore cellulose filters and cultured on BCYE agar and tryptic soya agar media. The presence of Legionella pneumophila was confirmed by real time PCR assay using primers-probe designed for the mip gene. Results: Legionella pneumophila, Pseudomonas aeroginosa and Acinetobacter were isolated from 5 (9.6%), 6 (11.4%) and 1 (1.8%) of the hospital water systems, respectively. This study demonstrated the presence of Legionella, Pseudomonas and Acinetobacter in water system in ICU wards of different hospitals in Tehran. Conclusions: Hot water from shower heads could be a potential source of infection for Legionella pneumophila. Water was also proved to contain Pseudomonas aeruginonsa, the main GNB-NE causing nosocomila pneumonia at Tehran hospitals. Care should be taken concerning cleanliness and decontamination of water supplies at ICUs for pathogenic organisms.