Micro-organisms contain 90% of cells in human body and trillions foreign genes versus less than 30 thousand of their own. The human colon host various species of microorganisms, appraised at more than 1014 microbiota and contained of over a thousand species. Although each one’s profile is separable, the relative abundance and distribution of bacterial species is the same between healthy ones, causing conservation of each person’s overall health. Germline DNA mutations have been attributed to the less than 5% of CRC occurrence while more than 90% is associated with the epigenetic regulation. The most ubiquitous environmental factor in epigenetic modification is gut microbiota. Disruptive changes in the gut microbiome strongly contributed to the improvement of colorectal cancer. Gut microbiota may play critical role in progression of CRC via their metabolite or their structural component interacting with host intestinal epithelial cell (IEC). Herein we discuss the mechanism of epigenetic modification and its implication in CRC development, progression even metastasis by gut microbiota induction.

Background and Objectives: Rv1733c is a latency antigen from Mycobacterium tuberculosis, a probable integral-membrane protein with promiscuous T-cell and B-cell epitopes, making it a potential vaccine candidate against tuberculosis. This study aimed to clone and optimize the expression of recombinant Rv1733c in Escherichia coli for purification.
Materials and Methods: Chemically synthesized rv1733c coding sequence was cloned in pET-23a(+) followed by transforming E. coli BL21 (DE3) cells. To evaluate the induction conditions for optimized expression, factorial design of experiments was employed using four different media as well as four levels of isopropyl-b-D-thiogalactopyranosid [IPTG] concentration and duration of induction. The recombinant protein was then purified using a His-tag purification kit and detected through western blotting.
Results: Recombinant Rv1733c (> 24 kDa) was expressed and accumulated in the cytoplasm of the E. coli cells. Medium composition showed the most significant effect on the yield of the recombinant protein (P = 0.000). The highest yield of recombinant Rv1733c occurred in the presence of 0.4 mM of IPTG in Terrific Broth medium (containing 1.2% tryptone, 2.4% yeast extract, 72 mM K2HPO4, 17 mM KH2PO4 and 0.4% glycerol) after 10 h at 37°C. Under these conditions, the expression level was around 0.5 g/L of culture medium. Purified Rv1733c was detected by an anti-polyhistidine antibody and a tuberculosis patient’s serum. Systematic optimization of induction conditions gave us high yield of recombinant polyhistidine-tagged Rv1733c in E. coli which was successfuly purified.
Conclusion: We believe that the purified Rv1733c recombinant protein from M. tuberculosis might be a good candidate for vaccine production against tuberculosis.

Background and Objectives: This study was undertaken to characterize antimicrobial resistance phenotypes and genes encoding extended spectrum β-lactamases (ESBLs) in Klebsiella isolated from retail chicken meat in Mansoura, Egypt.
Materials and Methods: Three hundred sixty chicken meat samples from 120 eviscerated chicken carcasses (3 cuts each) collected randomly from local retail chicken shops in Mansoura, Egypt during the period from April to June 2015, were assayed for the presence of Klebsiella by conventional bacteriological methods. Antimicrobial sensitivity for 12 antimicrobials using disk diffusion, ESBL phenotypic confirmation and PCR characterization of ESBL-encoding genes (blaTEM, blaCTX-M, blaOXA, blaSHV and blaCMY) were performed.
Results: Klebsiella was identified from 22.2% (80/360) of the samples. Of the 12 antimicrobials tested, multidrug resistance (MDR; resistance to ≥3 of the antimicrobial classes) was observed in 96.25% (77/80) of the Klebsiella isolates. All the isolates were resistant to cefotaxime, ceftriaxone and aztreonam. ESBL-producers were phenotypically confirmed in 48.75% (39/80) of the isolates. The highest values (0.75 and 0.67) of multiple antibiotic resistance (MAR) significantly occurred in ESBL-producing isolates. PCR findings showed a significantly higher occurrence of β-lactamase encoding genes in ESBL (94.9%, 37/39) than non-ESBL producing isolates (4.9%, 2/41). The distribution of blaTEM, blaCTX-M and blaOXA among ESBL-producing isolates was 84.6%, 30.8% and 25.6%, respectively.
Conclusion: Efficient monitoring and tracking of MDR, especially β-lactam resistance, in food sources is essential to predict the potential hazards for human infections.

Background and Objectives: Staphylococcus aureus is common pathogen that is associated with many hospital acquired infections. The virulence of S. aureus is identified with resistance to antibiotics especially to methicillin. Therefore the aims of the present study were to detect the carrier rates of methicillin-resistant S. aureus (MRSA) among health care Workers (HCWs) and patients and to compare use of specific chromogenic agar for MRSA culture with PCR for detection of MRSA genes.
Materials and Methods: Samples obtained were subjected to full microbiological laboratory studies involving culture on specific chromogenic medium and antibiotics susceptibility testing for detection of MRSA and their resistance rates to other commonly used antibiotics. Furthermore multiplex PCR was carried out to detect SCCmecA genes.
Results: Staphylococcus aureus was isolated from 70 (29.9%) of the studied subjects. MRSA isolates (n=28) had high resistance rates for the used antibiotics and the most common resistance was for ciprofloxacin and chloramphenicol (57.1% for each). MRSA was isolated mainly from health care workers (17.02%). The frequency of SCCmecA was 60.7% for type I, 25% for type III and 14.3% for type II. Chromogenic agar identified correctly MRSA isolates in 92.9%. PCR was positive in all isolates with resistance to cefoxitin disc.
Conclusion: The present study highlights that MRSA carriage is common among health care workers in one Egyptian tertiary care hospital. The major genotype of MRSA is belonging to SCCmecA type I followed by type III and type II. ChromID medium is an accurrate culture method for detection of MRSA compared to molecular method.

Background and Objectives: The objectives of this study were to evaluate the antibiotic resistance profiles, biofilm formation, presence of antigen 43 (Ag43) gene, and transfer of antibiotic resistance phenotype among non-O157 Shiga toxin producing Escherichia coli (STEC).
Materials and Methods: From October 2014 to November 2015 a total of 276 stool samples were collected from healthy calves, goats and 395 patients with the sign of nonbloody diarrhea and screened for presence of stx and serotype O157 genes by polymerase chain reaction (PCR) technique. Susceptibility to 14 antibiotics was determined as per CLSI guideline. Presence of Ag43 and intimin (eaeA) genes were detected by PCR. Biofilm formation was measured by microtiter plate method. Conjugation was carried out by membrane filter technique.
Results: We isolated 74 (93.6%) non-O157 STEC strains from 41 calves, 33 goats and 5 (6.3%) patients’ stools, however, no O157 serotype was detected in our study. Resistance was observed most commonly to tobramycin (66.2%), kanamycin (48.6%), and amikacin (29.7%) and less frequently to ciprofloxacin (4.1%), amoxicillin-clavulanic acid (5.4%), and ceftriaxone (9.5%) in isolates recovered from calves and goats fecal samples, whereas, all human isolates were sensitive to ceftazidime, ciprofloxacin, tobramycin and imipenem, respectively. Furthermore, Ag43 was detected in 60 STEC isolated from animals and 5 human origins (no eaeA gene was found in this study). Biofilm formation from Ag43+ and Ag43- colonies showed 20 isolates with strong biofilm activities. Cefotaxime resistance phenotype was transferred to E. coli ATCC 25922.1 (Nalr) by conjugation at a frequency of 1.6×10-4.
Conclusion: From the above results we concluded that, human infections with non-O157 STEC were significantly low in Kerman. Ag43 was insignificant with biofilm quantity in most cases.

Background and Objectives: The cytotoxin-associated gene (cag) pathogenicity island is reported to be a major virulence factor of Helicobacter pylori infection. It is previously reported that the cagA-positive strains are more virulent, so it can be postulated that the cagA-positive gastritis will be more severe and the serum immunoglobulin G (IgG) and A (IgA) anti-CagA antibody titer will be higher. The aim of this study was to compare the relationship between IgG and IgA anti-CagA antibody and the cagA gene expression in patients with dyspepsia. Serum samples obtained from 130 dyspeptic patients with positive H. pylori in histological and Geimsa staining were tested for serum IgG and IgA anti-CagA antibody using the enzyme-linked immunosorbent Assay. The expression of the cagA gene was determined using PCR on the biopsy samples, taken via endoscopy.
Results: In our material, the sensitivity of IgG anti-CagA antibody in identifying patients with a proven infection with the cagA-positive strains was 97.67%, and the negative likelihood ratios was 0.06. There was not significant correlation between serum IgA anti-CagA and the expression of the cagA gene among the dyspeptic patients.
Conclusion: The IgG antibody titer was significantly higher in our patients with the cagA-positive H. pylori strain. However, in daily practice, the level of the IgG antibody titer cannot predict whether or not an individual carries a cagA-positive H. pylori strain, because there is a major overlap in the IgG antibody titer between the cagA-positive and cagA-negative patients.

Background and Objectives: Arginine-rich peptides are an important class of antimicrobial peptides (AMPs) that exert their antibacterial activity via a lytic mechanism. Although the antibacterial activity of arginine-rich peptides has been already evaluated, no reports have so far been evaluated the influence of reaction conditions on their antimicrobial potential. The aim of the present study was to investigate the influence of pH, temperature, and glycine on antibacterial activity of poly-l-arginine (PLA) with a molecular weight of 5-15 kDa against Escherichia coli O157:H7 and Staphylococcus aureus.
Materials and Methods: The percentage of growth inhibition of PLA against both bacteria was analyzed at various pH, temperatures and sub-inhibitory concentrations of glycine by two-fold broth microdilution method.
Results: The results showed that PLA had antibacterial activity against E. coli O157:H7 and S. aureus and the inhibitory effect increased with increasing PLA concentration. The antimicrobial activity of PLA against both microorganisms was higher in basic media than under acidic or neutral conditions. At 1/2 times the MIC, heat treatment intensified the toxicity of PLA against E. coli O157:H7 whereas the susceptibility to PLA seems to be temperature independent for S. aureus. The MICs of glycine against E. coli O157:H7 and S. aureus were 12.5 and 25 mg ml-1, respectively. The antibacterial activity of PLA against both microorganisms increased, as indicated by the increasing growth inhibition percentage of this peptide with increasing glycine concentration.
Conclusion: The antibacterial activity of PLA against S. aureus and E. coli O157:H7 depends on pH and glycine concentration.

Background and Objectives: Viruses have been suggested as one of the risk factors for psychiatric disorders. Among infectious agents Borna disease virus (BDV) has been known as a neurotropic virus which is able to cause neurological disorders in different animals. Recently there were controversial findings about BDV association with pathogenesis of human psychotic disorders.
Materials and Methods: Here we performed a nested reverse transcription polymerase chain reaction for detection of BDV P40 RNA in peripheral blood mononuclear cell samples of schizophrenia (SC), bipolar disorder (BD) patients and healthy controls (HCs).
Results: Only one out of 120 (0.8 %) psychiatric patients and two samples (2.7%) in 75 HCs showed positive results. There were no significant molecular evidence of BDV infection in 120 psychotic patients (60 SC and 60 BD) and 75 matched HCs.
Conclusion: Our findings showed no association between BDV infection and pathogenesis of these psychiatric disorders. This is an interesting issue given both the as yet un-clarified role of BDV in human mental disorders and addressing patients in the so far under-investigating Middle East era.

Background and Objectives: Cryptococcal meningitis is one of the main opportunistic infections associated with human immunodeficiency virus (HIV) infection. Despite the present and increasingly availability of specific treatment for cryptococcosis, the mortality rate of this infection is still high, particularly in patients with advanced immunsupression and advanced cryptococcal diseases.
Materials and Methods: This Prospective Cohort study was conducted at Imam Khomeini hospital in Tehran, Iran. Serum cryptococcal antigen was detected using the Lateral Flow Assay (LFA) There were 86 HIV-infected patients included in this study.
Results: There were 86 HIV-infected patients in this study. The prevalence of positive serum cryptococcal antigen was 0% (0 of 86).
Conclusion: The prevalence of cryptococcal infection among patients with advanced acquired immunodeficiency syndrome (AIDS) in the Iran is very low (<3%) thus the screening test for cryptococcal antigenemia dose not save lives and is not cost-effective in Iranian population.