جستجوی مقالات مرتبط با کلیدواژه « Virulence genes » در نشریات گروه « زیست شناسی »

This study aimed to evaluate the prevalence of Campylobacter isolates based on the presence of certain invasive genes. The experimental study tested 392 samples from Behbahan city. After culturing the samples, microbial identification was performed using Gram staining. Molecular identification of Campylobacter isolates was then conducted using PCR and suitable primers for invasive genes cdtA, B, C, cadF, pldA, ciaB, and 16S rRNA. According to the Gram staining results, 50 samples were infected with Campylobacter. Of these, 37 (74%) were chicken samples, 8 (16%) were cow samples, 2 (4%) were sheep and goat samples, and 3 (6%) were water samples. Analysis of the 16S rRNA gene sequence showed that 72% of the contamination was related to Campylobacter jejuni and 28% was related to Campylobacter coli. Overall, the prevalence of Campylobacter jejuni in isolated samples was significantly higher than that of general Campylobacter (p=0.012). Among the Campylobacter jejuni isolates, the highest prevalence was related to the CdtC toxin production gene (76.2%), and among the Campylobacter coli isolates, it was related to the CdtB toxin production gene (30.2%). Although chickens are considered the main sources of Campylobacter species, it is necessary to investigate the significance of other contamination sources, especially cattle and sheep, to assess their role in human infections. Therefore, necessary precautions must be taken for human consumption, and hygiene standards must be maintained in storage areas, along the slaughter line, and in stores.

Pathogenic microorganisms are one of the important factors in contaminating and endangering the safety of foods for consumers, and continuous control of foods in terms of the presence of pathogenic microorganisms can guarantee the health of foods. Yersinia entrocolitica is a foodborne pathogenic bacterium. Raw milk and fresh traditional cheese may be contaminated with this bacterium. Generally, Iranians tend to consume traditional and homemade foods more than industrial products. This issue is especially relevant to milk products such as cheese, butter, and local cream. The purpose of this study was to determine the contamination of raw milk and traditional cheeses produced in Chaharmahal and Bakhtiari province with Yersinia entrocolotica.

A total, of 100 raw milk and 50 traditional cheese samples were obtained randomly from dairy plants and milk collection stations, as well as retail shops. The initial enrichment of the samples was performed in the TSB medium. Then, 100 microliters of the medium was centrifuged and 25 microliters of its sediment was cultured on the special medium of Cefsoludin Irgazan Novobiocin agar (CIN) with supplement (containing Cefsoludin 7.5 mg, Irgasan 0.2 mg and Novobiocin 1.25 mg). Suspicious colonies (red colonies) were identified on the CIN agar and biochemical tests including IMViC, Ureas, and H2S production.DNA extraction was performed by boiling method and polymerase chain reaction (PCR) was performed for the identification of Ali and Yst genes using specific primers (Table 1). Table 1. Characteristics of Primers Used to Identify Yersinia Enterocolitica Genes Antibiotic resistance test was performed by the disk diffusion method on Muller-Hinton agar according to the Clinical and Laboratory Standards Institute (CLSI). Resistance of Yersinia enterocolitica isolates to 7 commonly used antibiotics in treatment including cefixime (5µg), gentamicin (10µg), tryptoprim (5µg), ciprofloxacin (5µg), amoxicillin (10µg), tetracycline (30µg), and sulfamethoxazole (300µg).

Out of 100 samples of raw milk and 50 samples of traditional cheese, 20 samples (13.3%) suspected Yersinia enterocolitica bacteria were isolated. of these, 14 samples (14%) were related to raw milk samples and 6 samples (12%) were related to traditional cheese samples. The results of the PCR test showed that 5 isolates (3.3%) were Y. enterocolitica bacteria, 4 isolates (4%) related to raw milk, and 1 isolate (2%) related to traditional cheese. In addition, in the evaluation of virulence genes, it was found that out of 4 raw milk isolates, 1 isolate carried the Yst gene, 2 isolates carried the Ail gene, and 1 isolate had both genes. Also, 1 isolate of Y. enterocolitica isolated from traditional cheeses carried the Ail gene (Table 2). Table 2. Percentage of Contamination of Raw Milk and Traditional Cheese with Yersinia entrocolitica, (%) The results of antibiogram tests on Yersinia enterocolitica isolates showed the highest resistan.ce to Gentamicin, Trimethoprim, Ciprofloxacin, and Sulfamethoxazole antibiotics, and moderate resistance to cefixime and amoxicillin (Table 3).  Table 3. Antibiotic Resistance Pattern of Yersinia Entrocolitica Isolated from Raw Milk and Traditional Cheese.

In general, the results of the present study and other studies in Iran and the world show that raw milk and traditional cheeses, contaminated with Yersinia enterocolitica, which carry virulence genes and are resistant to some common antibiotics, can endanger the health of consumers.

Due to the widespread use of antimicrobials in veterinary medicine and the increase in livestock production, it seems that the risk of spreading antibiotic resistance in human societies is more related to animals and the veterinary field. In this study, antibiotic resistance and frequency of fimH, papC and sfa-foc virulence genes among Escherichia coli isolated from Caspian horse feces in Guilan were studied. In this cross- sectional study, E. coli isolates were isolated from the feces of 157 apparently healthy Caspian horses by culture method and biochemical tests. Resistance patterns against 17 different antibiotics were determined by disk diffusion method and frequency of virulence genes were assessed by PCR in isolates. In phenotypic assay of antibiotic resistance, the isolates showed the most resistance to streptomycin and sulfamethoxazole-trimetoprim antibiotics. Imipenem and gentamicin were the most effective antibiotics and 51.59 percent of isolates showed multi drug resistance pattern. The frequency of fimH, papC and sfa-foc virulence genes in isolates were 91%, 56.6% and 33.3%, respectively. Frequency of all of three investigated genes were significantly higher in MDR isolates (P< 0.05). The results of the present study indicate that Escherichia coli isolated from the feces of horses in Guilan has the potential to transmit antibiotic resistance and endanger public health.

Escherichia coli infections in poultry have a word wide spread. Serotypies O1, O2, O8, O35, O78 Escherichia coli is involved in the development of generalized colibacillosis disease. Genes such as F17, Sfa, pap, afa, , fimH , crl , iuc, bla, yja, chu, are considered as an Escherichia coli acuity factoro. the aim of the present study were Phylogentic of Escherichia coli isolates involved in Colibacillosis and cellucitis in broiler chickens in shahrebabak(Kerman Province) by Multiplex PCR Technique 

From 117 samples of Escherichia coli (83 colibacillosis samples and 34 cellulitis samples) were isolated. These samples were examined and confirmed by biochemical methods.

Colibacillosis isolates were belonged to A (54.27%), B1 (7.22%), B2 (6.03%) and D (32.53%) phylogroups. Where as, the isolates from cellulitis cases were belonged to three main phylogroups; A (55.88%), B1 (5.88%) and D (38.24%).

Statistical analysis showed a specific association between the presence of crl virulence gene and Phylogrups of A and D (P<0.05) in colibacillosis isolates.
The results showed that the isolates from both diseases in broiler chickens could be assigned to various phylogenetic groups (mainly A). Also, the virulence genes profile of cellulitis E.coli is completely different from that of colibacillosis in this region

 E. coli is a normal flura in the human and animal intestinal tract. This bacteria is one of the main cause of the urinary tract infection. The aim of this study was identification and simultaneously presence of 3 virulence factors, kpsMTII, iucD, usp in the genome of urinary tract infection E. coli strains.

 60 samples of E. coli, which caused urinary tract infection, were collected. These bacteria were isolated by biochemical tests and gram staining. Then bacteria genome was extracted by gram-negative bacteria DNA extraction kits.  Multiplex-PCR was used for identifying of 3 virulence factors.

 In these 60 samples of isolated E. coli, the prevalence of virulence genes is as follows: kpsMTII 71.66%, iucD 88.33%, and usp 36.66%. As also, simultaneously presence of 3 virulence factors were observed in 28.33% of samples. There was significant association between prevalence of these three genes and urinary tract infection in studied E. coli isolates (Pvalue<0.05).

 According to this study results, that was similar to previous researches, could be significant related between prevalence of these three genes in studied urinary tract infection E. coli samples.

Staphylococcus aureus is an opportunistic pathogen and one of the most important health-threatening agents worldwide. Expression of bacterial virulence factors is not similar in laboratory medium conditions and in vivo. The aim of the present study was to evaluate the effects of adding 5% calf serum on the virulence genes expression of S. aureus.   The expression levels of agrA, RNAIII, hla, spa, and mecA genes were     determined during the growth of S. aureus isolates in BHI broth and BHI broth enriching with calf serum during different growth phases. Therefore, the growth curve of the five isolates of S. aureus in two different culture conditions was plotted. Subsequently, RNA was extracted from different phases of growth and the genes expression were analyzed by Real-time PCR.   In average, the expression levels of agrA and RNAIII from stationary phase to the exponential phase in BHI broth containing calf serum was increased 3.4 and 9.5-fold, respectively, while the agr system could not appropriately play its regulatory role in the expression of virulence genes. As a result, the expression of hla gene was decreased 0.81-fold and the expression levels of spa and mecA genes was only increased 1.25 and 1.03-fold, respectively.   Regardless of the growth phase, the expression of the whole genes in BHI broth containing calf serum were increased in comparison to BHI broth. Consequently, it appears that S. aureus is capable to induce virulence genes expression in the presence of calf serum factors similar to conditions available in vivo.

Aim and Colorectal cancer is the third most common cancer after lung cancer, stomach and liver cancer in the world. Studies have shown that patients with inflammatory disease of the large intestine are at high risk of developing colorectal cancer are located. Several factors make inflammatory bowel disease and colorectal cancer is one of the factors involved, bacteria and toxins derived from them. Research shows that some strains of E. coli can be induced to increase the mutation rate that was established in 2010 by Cuvas-Romas and colleagues. fimC and vat1 Virulence genes in these organisms play an important role in bacteria pathogenicity. This study is to compare the virulence genes in E .coli strains isolated from samples biopsy patient's inflammatory bowel disease and colorectal cancer, intestinal tissue was performed.
38 biopsies were obtained from intestinal tissue and E.coli bacteria in microbial and biochemical method was identified and isolated. After DNA extraction, strains for virulence genes vat1, fimC using polymerase chain reaction (PCR), were evaluated.
Molecular analysis showed a significant difference between the groups studied the gene vat1 (p = 0.0245) and 42.8% of positive samples were for this gene in normal groups, 87.5% with inflammatory bowel disease87.5 % of patients with colorectal cancer were reported. But there is no significant difference between the groups in terms of fimC gene (P = 0.201). And 71.4% of positive samples for this gene in normal group's and 93.7% in patients with inflammatory bowel disease73.3 % of patients with colorectal cancer were reported.
The results, to confirm the good relationship between virulence genes studied induced inflammation and proliferation by inducing mutation rate.

The enterotoxigenic Staphylococcus aureus is considered as one of the most common agents of food poisoning, gastroenteritis, diarrhea and vomiting that the presence of bacterial virulence genes can be as the most important cause of this foodborn illness. The present study was conducted to determine the presence of S. aureus and its virulence factors in chicken nugget and ready to eat foods in Iran. In summer 2012 a total of 420 samples chicken nuggets were collected from randomly selected retail stores in Isfahan provinces, Iran. Samples were cultured and the positive results were studied using PCR for detection of sea-sej virulence genes. Results showed that 24 of 420 samples (5.7 %) were found to be contaminated with S. aureus. Also 23 of 24 isolated S. aureus were positive for one or more entrotoxin genes. The most detected genes were sea (25 %), sec (12.5 %), sed + sej (4.16 %), sed + seg (4.16 %), seg + sei (4.16 %), sea + seg (8.33 %), seb + sej + sei (4.16 %), sea + sed (12.5 %), sea + sec + sej (12.5 %). The most commonly detected genes were sea and sec.Discussion and The chicken nugget can be easily contaminated by the S. aureus and usually this contamination causes Staphylococcal food poisoning. Therefore, some food safety and quality standards need to be applied and performed in most of food units to control prevalence of S. aureus and its virulence factors. Nowadays, consumption of fast foods like chicken nuggets is very popular. Therefore, it is important to study the prevalence of enterotoxigenic S. aureus and its virulence genes in chicken nugget that this shows the important public health issue.

Shiga Toxin-Producing Escherichia coli (STEC) strains can infect humans via vegetal and animal food consumption and cause food poisoning with diarrhoeas, hemorrhagic colitis, haemolytic uraemic syndrome that can lead to death. The purpose of this study is isolation and identification of Escherichia coli O157:H7 virulence genes from Juice Purchase and vegetables in Shiraz. This cross- sectional study was performed on 89 samples of Juice Purchase and vegetables collected from Shiraz. Isolates were enriched in ECB with novobiocin medium in temperature 37C. After, in order to examine the fermentation of sorbitol and lactose the CT-SMAC and VRBA media and the activities of β-glucoronidase of separated bacteria were examined using the choromoagar medium. Then, the existence of E.coli O157:H7 was confirmed with the spesific antiserum. Finally, virulence genes stx1, stx2, eae and hly were tested by multiplex PCR and rfb O157 ang fliC H7 were tested by single PCR. Out of all examined samples 69 (77.53%) sorbitol negative bacteria were separated that after evaluation with specific antiserum 21 (23.60%) E.coli O157:H7 was detected. The molecular markers, stx1 genes in 3 samples and eae, stx1 in 1 sample were detected. Intensive studies of the sources, incidence, fate and transport of E.coli O157 near produce production are required to determine the mechanisms of pre-harvest contamination and potential risks for human.