Phylogenetic relationship, virulence factors, and biofilm formation ability of human, pet animals, and raw milk Staphylococcus aureus isolates.

Background: Identification of genotypic characteristics and pathogenicity of Staphylococcus aureus isolates is very important in the epidemiological study of its related diseases. Aims: The present study was done to compare the S. aureus isolates from different sources on the basis of virulence gene properties, biofilm production ability, and phylogenetic variations. Methods: Seventy S. aureus isolates (including 25 human, 25 raw milk, and 20 pet animal isolates) were subjected to slime production ability testing, polymerase chain reaction (PCR) detection of 14 different virulence genes, and DNA fingerprinting using restriction fragment length polymorphism (RFLP) of coa gene PCR products. Results: Among 70 S. aureus, 64 (91.4%) isolates were slime producers on Congo red agar (CRA) medium. The spa and icaD virulence genes were present in all isolates and the seD and etaA genes were not detected in any of the isolates. In total, 22 different virulence gene patterns and nine distinct clusters of coa-PCR-RFLP were identified among isolates. Conclusion: According to the results, S. aureus strains of human origin showed a significant association with specific virulence gene profiles and genotypes. seB and seC were the most responsible genes for S. aureus enterotoxin among human and animal isolates, respectively. Coa-RFLP showed partially appropriate results in the classification and source detection of S. aureus isolates.

Isolation and identification of keratinolytic probiotic Bucillus licheniformis bacteria from the soil below poultry slaughterhouse waste.

Feathers make up 7% of the total weight of adult chickens and keratin protein makes up 85% of the feathers. Today, the keratinase enzymes of some Bacillus strains are used to degrade and process raw keratin waste for animal and poultry feed. According to various studies, the probiotic properties of some spore-shaped Bacillus have also been proven. The study aimed to isolation of the keratinolytic Bacillus bacteria that they have probiotic properties for using in the livestock and poultry feed industry. We were able to isolate 8 strains of Bacillus licheniformis with kreatin degrading properties from the soil of Baharan chicken slaughterhouse (Qom city, Iran) applying heat shock, alcohol- and keratin-rich culture medium, and after microscopic and biochemical analysis, 16S rDNA gene was isolated. The measurement results of keratinase activity showed that the three strains of Bacillus licheniformis pvkr6, pvkr 15, and pvkr41 had the highest activity with 124.08, 101.1, and 100.18 U/ml. The results of probiotic properties evaluation also revealed that among all the isolates, only Bacillus licheniformis pvkr15 and Bacillus licheniformis PTCC 1595 (positive control) were γ-hemolytic strains. The percentage of surface hydrophobicity of the strains was obtained from 3.27 to 30.57. It was also shown that, on average, all the strains had acceptable susceptibility to the tested antibiotics except penicillin G. Bacillus licheniformis pvkr15 with highest keratinase activity (101.1U/ml) was considered an optional probiotics due to its abilities such as (biofilm formation, being safe cause of γ-hemolytic activity, high susceptibility to antibiotics such as streptomycin, gentamicin, cefixime, amoxicillin, tetracycline, vancomycin, erythromycin and having a moderate hydrophilic (hydrophobicity: 19.09%), high survivability in pH 2, 2.5 and 3, strong resistance to bile salts and moderate antagonistic activity against pathogenic bacterium like Proteus mirabilis and the ability to grow under anaerobic conditions). By using this strain, after hydrolysis of keratin protein in the feather structure, to replace part of the protein of livestock and poultry feed, not only is no need to separate bacteria from the feed, but also the strain play role of an useful and effective additive in animal growth.

Phylogenetic relationship and virulence gene profiles of avian pathogenic and uropathogenic Escherichia coli isolated from avian colibacillosis and human urinary tract infections (UTIs).

BACKGROUND: There is evidence representing the possible relationship between avian pathogenic Escherichia coli (APEC) and other extraintestinal pathogenic E. coli (ExPEC) strains such as human uropathogenic isolates. AIMS : The present study was conducted to evaluate virulence and phylogenetic relationship between a total of 70 APEC and UPEC isolates (35 APEC and 35 UPEC isolates) obtained from the north of Iran which is one of the core areas of the country's poultry industry. METHODS: Polymerase chain reaction (PCR) and random amplified polymorphism DNA (RAPD) analyses were conducted using specific primers, and data was analyzed using BioNumerics and SPSS softwares. RESULTS: The most prevalent gene was fliC (70.6%) followed by fimH (67.1%), but APEC and UPEC isolates showed inordinate and obvious differences in the presence of some virulence genes such as fliC, hlyD, and sfa1 and predominant phylogenetic groups in DNA fingerprinting methods. CONCLUSION: The results showed obvious differences existed between isolates of APEC and UPEC in terms of phylogenetics and pattern of virulence gene; however, despite having virulence genes such as papC, ibeA, and iss, APEC isolates can have a high potential for causing disease in humans and may generate dangerous outbreaks in communities with low levels of hygiene in public and the poultry industry.

Identification of the classical enterotoxin genes of Staphylococcus aureus in various foods by multiplex PCR assay.

BACKGROUND: An annual update of information about the prevalence of Staphylococcus aureus and staphylococcal enterotoxins (SEs) genes is required in every geographic area. AIMS: This study was conducted to investigate the prevalence of the bacterium and type of associated enterotoxin genes in different food samples, using multiplex polymerase chain reaction (PCR) assay. METHODS: In order to achieve these goals, 310 samples, divided into three groups (dairy products, meat, and traditional sweets groups), were collected. After determination of the prevalence of S. aureus, the existence of 16s rRNA, sea, seb, sec, sed, and see genes were evaluated using multiplex PCR assay. RESULTS: Staphylococcus aureus was isolated from 103 (33%) samples. Furthermore, the meat category had the most contamination rate of S. aureus. Additionally, the kebab samples (61.5%) were the most contaminated products, followed by hamburger (47.3%), and ice cream (33.8%). Of these 103 S. aureus isolates, 72 isolates (69.9%) harbored at least one type of the classical SEs genes. The prevalence of the type A enterotoxin gene was detected higher than the other SEs genes. CONCLUSION: The results indicated that inappropriate handling of the samples in the preparation and processing steps, especially for the meat products, can lead to the spread of more bacteria. The relatively high prevalence of some classical enterotoxin genes in the isolates revealed the potential power of this bacterium to produce enterotoxins, which can lead to food-poisoning.