Hamid Staji

Bio: Hamid Staji is an academic researcher from Semnan University. The author has contributed to research in topics: Escherichia coli & Salmonella. The author has an hindex of 6, co-authored 41 publications receiving 137 citations.

Genetic Characterization of Escherichia coli O157:H7 Strains Isolated from the One-Humped Camel (Camelus dromedarius) by Using Microarray DNA Technology

Abstract: From the Camelidae family members, several serotypes of Escherichia coli (E. coli) have recently been isolated from diarrhoeic and non-diarrhoeic faecal samples. To date Shiga toxin-producing E. coli (STEC) strains have never been typed in one-humped camel (Camelus dromedarius). In the present study, two E. coli O157:H7 strains isolated from sick dromedaries were investigated. Virulence gene profiles were determined using a custom E. coli virulence DNA microarray, composed of 70-mer oligonucleotide probes targeting 264 virulence or related genes of known E. coli pathotypes. Both strains displayed positive hybridization signals for the Locus of enterocyte effacement (LEE) gene probes (ler, eae, espA, espB, tir genes), two Shiga toxin probes (stx1 and stx2), the O157 O-antigen specific probe, various virulence plasmid (pO157) probes like katP in addition to other accessory virulence genes characterized in STEC.

The effect of dietary zataria multiflora boiss. essential oil supplementation on microbial growth and lipid peroxidation of broiler breast fillets during refrigerated storage

Abstract: Seventy-two 1-day-old broilers were allocated into four groups (basal diet as control, basal diet supplemented with 100, 200, and 400 mg/kg Zataria multiflora essential oil) and fed for 6 weeks. In the term, chicks were slaughtered and their breast fillets were stored at 4C for 12 days. Lipid peroxidation was assessed on the basis of thiobarbituric acid reactive substances formed, whereas microbial growth was assessed on the basis of total viable counts, lactic acid bacteria, Enterobacteriaceae and psychrotrophic bacteria. Results indicated that incorporation of Z. multiflora essential oil in broiler diets caused the delay of lipid peroxidation in raw breast meat (from 296.08 to 472.65 mg/kg malondialdehyde [MDA] equivalents) in comparison with 854.71 mg/kg MDA equivalents of the control sample at the last day of the experiment (P < 0.05). Moreover, breast samples containing higher concentration of Z. multiflora essential oil showed lower bacterial count than the control and 100 ppm essential oil supplemented samples (P < 0.05) during the experiment.

Comparative virulotyping and phylogenomics of Escherichia coli isolates from urine samples of men and women suffering urinary tract infections.

Abstract: Objective(s): Escherichia coli strains are common pathogens that can cause urinary tract infections (UTI). This study aimed to assess E. coli phylogroups and virulence types in male and female UTI patients.Materials and Methods: In the present study, 160 uropathogenic E. coli (UPEC) isolates (from both sexes) were assigned to phylogroups/types and some extraintestinal virulence factors were detected within them by multiplex-PCR.Results: The isolates from women and men were predominantly distributed within phylogroup B2 and D, respectively. The presence of D2 phylotype was higher in men isolates than women, significantly (P=0.045). In male isolates papEF and sfa/focDE are more prevalent in B2 group than D, significantly (P=0.048; P=0.035). The prevalence of hly in B2 group is significantly higher than D (P=0.034) in female isolates.Conclusion: This study highlighted different features of E. coli genotypes from phylogenetic and virulence point of view implicated in UTI’s in both human genders.

Phylogenetic Grouping and Assessment of Virulence Genotypes, With Antibiotic Resistance Patterns, of Escherichia Coli Strains Implicated in Female Urinary Tract Infections

Abstract: Background: Escherichia coli strains are common pathogens that can cause urinary tract infections (UTIs). They are classified into phylogroups based on three genetic markers: chuA, yjaA, and TspE4.C2. The E. coli strains that cause UTIs possess several genes that encode urovirulent factors and antimicrobial-resistance phenotypes. We determined the phylogenetic groups of E. coli isolates from UTI cases in Sabzevar, Iran, the prevalence of certain virulence genes, and the antibiotic-resistance phenotypes in these strains. Objectives: The aim of this study was to assess the correlation of detected E. coli phylogroups in female UTI patients with the antibioticresistance pattern and the distribution of certain virulence factors among the phylogroups. Materials and Methods: Ninety-three E. coli isolates from 150 women with UTI were studied. Three genetic markers were detected for phylogenetic grouping of strains, and four virulence determinants were analyzed with multiplex-PCR, including the genes for hemolysin (hly), aerobactin (iucD), P fimbriae (pap), and S/F1C fimbriae (sfa/focDE). The antibiotic-resistance phenotypes were also determined. Results: The isolates from UTI cases were distributed within phylogroups A (31%), B1 (10%), B2 (28%), and D (31%). The prevalence of iucD, hly, pap, and sfa/focDE virulence genes was significantly associated with groups B2 and D. The most-resisted antibiotics were cefazolin (93%) and co-trimoxazole (68%), while the isolates were most sensitive to nitrofurantoin (1%) and imipenem (2%). Conclusions: The phylogroups of E. coli isolates from UTI cases showed that groups D, B2, and A are prevalent in women in Sabzevar, as the dominant pathogenic phylogroups. The comparison showed that there was no significant difference in the occurrence of virulence factors or in the distribution of antibiotic resistance between urinary E. coli isolates, but the virulence genes were distributed more into groups B2 and D, respectively. Our study showed that the highest sensitivity was to nitrofurantoin and imipenem, but the decision on a treatment strategy remains based on the physician’s diagnosis and the antimicrobial-resistance tests.

Antioxidant capacity of phytochemicals and their potential effects on oxidative status in animals - A review.

Abstract: Oxidative stress suppresses animal health, performance, and production, subsequently impacting economic feasibility; hence, maintaining and improving oxidative status especially through natural nutrition strategy are essential for normal physiological process in animals. Phytochemicals are naturally occurring antioxidants that could be considered as one of the most promising materials used in animal diets in various forms. In this review, their antioxidant effects on animals are discussed as reflected by improved apparent performance, productivity, and the internal physiological changes. Moreover, the antioxidant actions toward animals further describe a molecular basis to elucidate their underlying mechanisms targeting signal transduction pathways, especially through the antioxidant response element/nuclear factor (erythroid-derived 2)-like 2 transcription system.

Campylobacters as zoonotic pathogens: a food production perspective.

Abstract: Campylobacters remain highly important zoonotic pathogens worldwide which infect an estimated 1% of the population of Western Europe each year. Certain campylobacters are also important in infections of animals, particularly of the reproductive tract, and some are involved in periodontal disease. This paper focuses, however, on the two species which are most important in food-borne infections of humans, Campylobacter (C.) jejuni and C. coli. Infection with these campylobacters is serious in its own right but can also have long-term sequelae such as reactive arthritis and Guillain-Barre syndrome. The pathogens are ubiquitous in nature and in domestic animals and, as a consequence, are found frequently in the environment and on many raw foods, of both plant and animal origin and bacterial numbers can be very high on certain key foods like raw poultry meat. Although all commercial poultry species can carry campylobacters, the risk is greater from chicken because of the high levels of consumption. Campylobacters are relatively 'new' zoonotic pathogens as routine culture from clinical specimens only became possible in the late 1970s. As a consequence there is much that still needs to be understood about the behaviour and pathogenicity of these highly important bacteria. In particular, and from a food industry/food safety perspective, it is important to better understand the behaviour of C. jejuni and C. coli in the food production environment, and how this affects their ability to survive certain food production processes. There is a belief that campylobacters are much more sensitive to hostile conditions than either salmonellas or Escherichia coli. Much of data to support this view have been derived from laboratory experiments and may not fully represent the natural situation. Studies are showing that campylobacters may be more robust than previously thought and thus may represent a greater challenge to food safety. We recommend that research is undertaken to better understand how campylobacters behave in the food chain and how responses to relevant conditions affect their ability to survive processing and their virulence. There is also a need to better understand the reasons why campylobacters are capable of frequent change, particularly in the expression of surface antigens.