Prevalence of tetracycline resistance determinants in broiler isolated Escherichia coli in Iran.

1. Tetracycline resistance determinants are widespread among bacterial species. Resistance to tetracycline occurs by different mechanisms regulated by various genes. 2. The study was conducted to determine the tetracycline resistance and prevalence of tetracycline resistance determinants among Escherichia coli strains isolated from broilers in northern Iran. 3. Minimum inhibitory concentration (MIC) of tetracycline and susceptibility pattern of the isolates were screened using micro-dilution and disk diffusion methods, respectively. The presence of 7 tetracycline resistance genes including tetA, tetB, tetC, tetD, tetE, tetG and tetM was tested using the polymerase chain reaction. 4. Among 100 strains isolated from broilers, 73% were identified as tetracycline resistant. All isolates showed the presence of tetracycline-associated genes. The most prevalent genes were tetA (46%) and tetB (41%) and totally, 17 different genotypes were recognised according to the presence of tetracycline resistance genes. Statistical analysis revealed that concomitant presence of the resistance genes significantly increased the tetracycline MIC and effectiveness of phenotypic characterisation. 5. The results demonstrated a high occurrence of tetracycline-resistant E. coli and related genes among broilers which presents a risk of increasing these strains in human infections associated with food animals.

Occurrence of Arcobacter in Iranian poultry and slaughterhouse samples implicates contamination by processing equipment and procedures.

1. The occurrence of Arcobacter spp. and three pathogenic species of Arcobacter from Iranian poultry carcasses was investigated at different steps of broiler processing to determine critical control points for reducing carcass contamination. 2. Samples were collected from (a) cloaca immediately before processing, (b) different points during processing and (c) at different stations in a processing plant of a slaughterhouse in southern Iran. 3. After enrichment steps in Arcobacter selective broth, DNA of the samples was extracted and three significant pathogen species of Arcobacter were identified based on polymerase chain reaction (PCR) detection of 16S rRNA and specific species PCR. 4. Out of a total of 540 samples, 244 (45%) were positive for Arcobacter spp. Arcobacter butzleri was more frequently detected (73% ± 13.9%) than A. cryaeophilus (9% ± 13.9%) and A. skirrowii (4.1%). In addition, co-colonisation (A. butzleri and A. cryaerophilus) occurred in 13.9% of the positive samples. 5. The results indicate a high prevalence of Arcobacter in the investigated slaughterhouse and broiler carcasses and that Arcobacter is not a normal flora of the broilers. Evidence for the presence of Arcobacter in the environment and water of processing plants suggests that these are sources of contamination of poultry carcasses. In addition, contamination of the poultry carcasses can spread between poultry meats in different parts and processes of the slaughterhouse (pre-scalding to after evisceration).

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, characterization, and genotyping of Ornithobacterium rhinotracheale isolated from broiler and broiler breeder flocks in Mazandaran province, Northern Iran.

Background: Ornithobacterium rhinotracheale (ORT) is one of the most important pathogenic bacteria which cause significant economic losses in poultry breeder countries every year. Aims: The present study was conducted to isolate and investigate the ORT isolates' biochemical, antibiotic resistance, and genotypic characteristics of in industrial poultry flocks with respiratory signs in northern Iran. Methods: After sampling from 60 different flocks and cultivation of the samples on a selective medium, suspected colonies were subjected to biochemical and molecular identification of ORT. Then, confirmed isolates were aimed to antibiotic resistance assay, hemagglutination test, detection of pOR1 plasmid, and DNA fingerprinting to survey the variability of the isolates. Results: A total of 13 isolates, including seven isolates from broiler flocks (19.44%) and six isolates from broiler breeder flocks (25%) were obtained. Almost all isolates showed similar results in terms of basically important biochemical tests. The most resistance rates among all ORT isolates were obtained for ampicillin, erythromycin, ceftriaxone, and penicillin (100%). The majority of ORT isolates were susceptible to furazolidone. The pOR1 plasmid was detected in only two isolates, and analysis of the DNA fingerprinting phylogenetic tree showed four specific genotypic clusters. Conclusion: According to the results, the isolates showed different antibiotic resistance profiles, and most of the strains proved multiresistant. This can indicate the circulation of various multi-drug resistant strains among poultry farms in northern Iran. Isolates from broilers and broiler breeders were grouped into different clusters by genotyping.

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.

Characterization of hemolysins of Staphylococcus strains isolated from human and bovine, southern Iran.

The staphylococci are important pathogenic bacteria causing various infections in animals and human. Hemolysin is one of the virulence factors of coagulase-positive (CPS) and coagulase-negative staphylococci (CNS). The aims of the study were to characterize hemolysins of Staphylococcus spp. isolated from human and bovine origin, phenotypic- and genotypically. Characterization of hemolysin phenotypically based on hemolysis pattern of Staphylococcus spp. was done on the sheep, horse and rabbit blood agar plates. Genes encoding hemolysin were amplified with specific primers by using polymerase chain reaction (PCR) technique. Hemolytic activities phenotypically were determined in 60 and 90% of the total bovine and human isolates, respectively. All non hemolytic isolates were CNS (P≤0.05). In all isolates, hla and hld genes were determined by PCR amplification. None of the bovine and human isolates showed phenotypically and genotypically gamma hemolysin. The results from this study suggest that, in accordance with what is generally believed, some differences are apparent in hemolysin types among Staphylococcus strains of bovine and human origin. Furthermore, this study showed that CNS can be important as new pathogens.