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Methicillin-resistant S. aureus (MRSA) strains circulating among populations and crossing borders constitute a major problem for health control and require a fast and simple genotypic approach. The objective of this study was to determine the prevalence, molecular types and drug resistance pattern of S. aureus isolated from Hospitalized Patients in teaching Hospitals of Ahvaz. this cross-sectional study was from April to September 2023, MRSA strains were identified by phenotypic and molecular methods. The antibiotics studied were), Cefoxitin (15 μg) Gentamicin (10 μg), Ciprofloxacin (5 μg), Erythromycin (15 μg), Clindamycin (2 μg), linzolide(10μg), azithromycin(5 μg). The tests were performed according to the guidelines of clinical and Laboratory Standards Institute (CLSI). It also detected the mecA gene of Methicillin-resistant S. aureus strains (MRSA). 470 Staphylococcus aureus samples from patients hospitalized in different departments of Ahvaz Hospitals included 283 blood culture samples, 75 wound samples, 72 body fluid samples and 40 catheter samples, and 321 (68.3%) MRSA isolates were reported. All these 321 MRSA isolates were tested with ampicillin, ciprofloxacin, clindamycin, linezolid, gentamicin, erythromycin, and azithromycin antibiotics. Also, the results of molecular identification of the mec A gene in 321 strains of S. aureus showed that 312 strains carry the mec A gene. The high prevalence of S. aureus samples can be caused by long-term hospitalization of patients in the ward and excessive use of antibiotics to treat the infection and increased resistance in isolates. As a result, more monitoring of the hospital's infection control department, as well as the expansion of the correct use of antibiotics, seems necessary and important.

Abstract Background Honey exhibits a broad spectrum of antibacterial activity against Gram‐positive and Gram‐negative bacteria, including methicillin‐resistant Staphylococcus aureus (MRSA) ones. Chitosan (Cs) is a mucoadhesive polymer that also has antibacterial properties. Special attention has been paid to the design of polymeric nanoparticles (NPs) as new nano drug delivery systems to overcome bacterial resistance and its problems. Objectives The aim of the present study is to synthesize Cs‐meropenem NPs with/without honey as an antibiofilm and antibacterial agent to inhibit Staphylococcus aureus. Methods This study synthesized meropenem and honey‐loaded Cs nanogels and subsequently characterized them by Field Emission Scanning Electron Microscopy (FESEM), Fourier Transform Infrared Spectroscopy (FTIR), and DLS‐zeta potential. Using the broth microdilution and crystal violet assays, the antibacterial and antibiofilm activity of meropenem and honey‐loaded Cs nanogel, free meropenem, free honey, and free Cs NPs were investigated in vitro against MRSA strains. 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyl‐2H‐tetrazolium bromide (MTT) was also used to test the cytotoxicity of several Cs‐NPs compound against the HEK‐293 regular cell line. Results The average size of meropenem and honey‐Cs‐NPs was reported to be 119.885 nm, and encapsulation efficiency was 88.33 ± 0.97 with stability up to 60 days at 4°C. The NPs showed enhanced antibiofilm efficacy against S. aureus at sub‐minimum inhibitory concentrations. Additionally, the cytotoxicity of meropenem and honey‐encapsulated Cs against the HEK‐293 normal cell line was insignificant. Conclusions Our findings suggested that meropenem and honey‐Cs‐NPs might be potential antibacterial and antibiofilm materials.

Abstract Background Bovine alphaherpesvirus 1 (BoHV‐1) is a serious disease with severe negative economic effects on the global cattle sector, especially in Iran. Objective This cross‐sectional study was carried out to examine the seroprevalence and associated risk factors of BoHV‐1 infection with progesterone levels and embryo death in 30‐day pregnant dairy cattle at Zagros Industrial Dairy Farm in Shahrekord, Iran. Methods Between December 2017 to February 2018, blood samples were obtained from 60 dairy cow herds. To determine whether BoHV‐1 was present, serum samples were examined using the ELISA for serum antibodies. To find progesterone (P4) in blood, the progesterone ELISA test was used. Results 96.7 % of sera tested positive for BoHV‐1 antibodies, according to the findings. Additionally, 60.34 % of blood samples that tested positive had an experience of abortion and significantly more inseminations that resulted in pregnancy, consistent with findings from other studies conducted in Iran and other nations. Conclusions Since this study is the first to document the risk factor for BoHV‐1 infection in Shahrekord, Iran, we could infer that the virus is extensively dispersed in this area.

Abstract Background The lack of appropriate vaccines is an obstacle to the effective management of A. baumannii infections. Peptide vaccines offer an attractive and promising preventive strategy against A. baumannii. Objective In this study, we identified specific T cell epitopes of A. baumannii outer membrane protein K (OMPK) using comprehensive bioinformatics and detailed molecular docking analysis. Methods Both class-I and class-II T cell epitopes of A. baumannii OMPK were predicted by three tools namely IEDB, SYFPEITHI, and ProPred. The predicted epitopes were shortlisted based on several analyses including prediction scoring, clustering, exclusion of human similarity, considering immunogenicity and cytokine production, and removal of toxic and/or allergen epitopes. The epitopic peptides with high prediction scores and appropriate properties containing both class-I and class-II T cell epitopes were selected. Two of these class I/II epitopic peptides were chosen for molecular docking studies and assessing their physicochemical properties as vaccine candidates. Results The results showed many T-cell epitopes of OMPK that could be evaluated for possible immunogenicity. Two of these epitopes (containing both class-I and II epitopes) had high prediction scores, were predicted by several tools, attached to several HLAs, and had the best docking score. They had different physicochemical properties and were conserved among Acinetobacter species. Discussion We identified the A. baumannii OMPK high immunogenic class-I and class-II T cell epitopes and introduced two promising high immunogenic peptides as vaccine candidates. It is recommended to perform in vitro/in vivo investigation of these peptides to determine their true efficacy and efficiency.

Abstract Salmonellosis, a zoonotic disease, is one of the leading causes of foodborne illness worldwide. It is responsible for most infections caused by consumption of contaminated food. In recent years, a significant increase in the resistance of these bacteria to common antibiotics has been observed, posing a serious threat to global public health. The aim of this study was to investigate the prevalence of virulent antibiotic-resistant Salmonella spp. strains in Iranian poultry markets. A total of 440 chicken meat samples were randomly selected from meat supply and distribution facilities in Shahrekord and tested for bacteriological contamination. After culturing and isolating the strains, identification was performed using the classical bacteriological method and PCR. To determine antibiotic resistance, a disc diffusion test was performed according to the recommendations of the French Society of Microbiology. PCR was used to detect resistance and virulence genes. Only 9% of the samples were positive for Salmonella. These were Salmonella typhimurium isolates. All Salmonella typhimurium serotypes tested positive for the rfbJ, fljB, invA and fliC genes. Resistance to TET, cotrimoxazole, NA, NIT, piperacillin/tazobactam and other antibiotics was found in 26 (72.2%), 24 (66.7%), 22 (61.1%) and 21 (58.3%) isolates, respectively. The sul1, sul2 and sul3 genes were present in 20, 12 and 4 of 24 cotrimoxazole-resistant bacteria, respectively. Chloramphenicol resistance was found in six isolates, but more isolates tested positive for the floR and cat two genes. In contrast, 2 (33%) of the cat three genes, 3 (50%) of the cmlA genes and 2 (34%) of the cmlB genes were all positive. The results of this investigation showed that Salmonella typhimurium is the most common serotype of the bacterium. This means that most of the antibiotics commonly used in the livestock and poultry industries are ineffective against most Salmonella isolates, which is important for public health.

Campylobacter jejuni and Campylobacter coli portion as an important food-borne pathogen owing to the consumption of raw milk of animal species is unmoving unidentified. This survey appraised both phenotypic and genotypic patterns of antimicrobial resistance amongst the C. jejuni and C. coli strains isolated from raw milk samples. Totally, 850 raw milk samples were examined for C. jejuni and C. coli. After culture, species identification was done using PCR. Phenotypic and genotypic patterns of antimicrobial resistance were assessed using disk diffusion and PCR, respectively. One hundred and ten out of 850 (12.94%) raw milk samples were contaminated with Campylobacter spp (95% confidence interval). The highest contamination rate with Campylobacter spp. was observed in raw cow milk (18.18%). C. jejuni and C. coli species were detected in 45.45% and 32.72% of Campylobacter isolates, respectively (P

Abstract Background Campylobacter jejuni and Campylobacter coli are the most significant Campylobacter species responsible for severe gastrointestinal disorders. Raw poultry meat is considered a source of Campylobacter transmission to the human population. Objectives The present study was aimed to assess the prevalence rate, antibiotic resistance properties, virulence characters and molecular typing of C. jejuni and C. coli strains isolated from raw poultry meat samples. Methods Three hundred and eighty raw poultry meat samples were collected and analysed for the presence of Campylobacter spp. using the microbial culture. Species identification was done using the Polymerase Chain Reaction. Disk diffusion was developed to assess the antimicrobial resistance pattern of isolates. The distribution of virulence and antimicrobial resistance genes was determined by PCR. Enterobacterial Repetitive Intergenic Consensus‐PCR was used for molecular typing. Results Campylobacter species were isolated from 6.25% of examined samples. C. jejuni and C. coli contamination rates were found to be 57.44% and 48.14%, respectively. C. jejuni strains harboured the highest resistance rate against serythromycin (42.59%), ampicillin (38.88%), ciprofloxacin (33.33%), chloramphenicol (31.48%) and tetracycline (31.48%). C. coli isolates harboured the highest resistance rate against ampicillin (73.07%), ciprofloxacin (73.07%), erythromycin (65.38%) and chloramphenicol (50%). AadE1 (44.44%), blaOXA‐61 (42.59%) and tet(O) (35.18%) were the most commonly detected resistance genes in C. jejuni and cmeB (34.61%) and blaOXA‐61 (34.61%) were the most commonly detected among C. coli strains. The most frequent virulence factors among the C. jejuni isolates were flaA (100%), ciaB (100%), racR (83.33%), dnaJ (81.48%), cdtB (81.48%), cdtC (79.62%) and cadF (74.07%). The most frequent virulence factors among the C. coli isolates were flaA (100%), ciaB (100%), pldA (65.38%) and cadF (61.53%). Conclusions The majority of C. jejuni and C. coli strains had more than 80% similarities in their ERIC‐PCR pattern, which may show their common source of transmission. The role of goose and quebec meat samples as reservoirs of virulent and antimicrobial resistant Campylobacter spp. was determined.

Outer membrane protein W (OmpW) is a less-known A. baumannii antigen with potential immunogenic properties. The epitopes of this protein are not well-identified yet. Therefore, in the present study, B- and T-cell epitopes of A. baumannii OmpW were found using comprehensive in silico and partially in vitro studies. The T-cell (both class-I and class-II) and B-cell (both linear and conformational) epitopes were predicted and screened through many bioinformatics approaches including the prediction of IFN-γ production, immunogenicity, toxicity, allergenicity, human similarity, and clustering. A single 15-mer epitopic peptide containing a linear B-cell and both classes of T-cell epitopes were found and used for further assays. For in vitro assays, patient- and healthy control-derived peripheral blood mononuclear cells were stimulated with the 15-mer peptide, Phytohemagglutinin, or medium alone, and cell proliferation and IFN-γ production assays were performed. The bioinformatics studies led to mapping OmpW epitopes and introducing a 15-mer peptide. In vitro assays to some extent showed its potency in cell proliferation but not in IFN-γ induction, although the responses were not very expressive and faced some questions/limitations. In general, in the current study, we mapped the most immunogenic epitopes of OmpW that may be used for future studies and also assayed one of these epitopes in vitro, which was shown to have an immunogenicity potential. However, the induced immune responses were not strong which suggests that the present peptide needs a series of biotechnological manipulations to be used as a potential vaccine candidate. More studies in this field are recommended.

Abstract Background Arcobacter spp. has been considered an emerging foodborne pathogen and a hazard to human health. The dairy chain has been isolated from different sources; nevertheless, data on Arcobacter occurrence in raw milk and dairy products in Iran are still scant. Objective The present study investigates the prevalence, antimicrobial susceptibility and the presence of virulence genes of Arcobacters species isolated from milk and dairy products. Methods Then, a total of 350 raw milk samples and 400 dairy product samples were collected from dairy supply centers in Isfahan, Iran. Presumptive Arcobacter strains were obtained by enriching samples in Oxoid Arcobacter enrichment broth (AEB) followed by the filtration of enrichment product through 0.45‐μm pore size membrane filters laid onto non‐selective blood at 30°C under microaerophilic conditions. Molecular identification of Arcobacter cryaerophilus and A. butzleri was performed by Polymerase chain reaction (PCR) amplification of the 16S rRNA gene, followed by sequencing. The disc diffusion method was used to determine the antimicrobial susceptibility of isolates. Targeted resistance and virulence genes were detected using multiplex PCR. Results The results show a low recovery rate of Arcobacter spp. in milk. Arcobacters were found in all types of milk, except raw camel milk, but were absent from all dairy products. Arcobacter butzleri was the predominant species in raw milk. Detection of virulence genes shows that all virulence genes targeted were found among A. butzleri, and six (cadF, cj1349, irgA, mviN, pldA, tlyA) were found among A. cryaerophilus. All A. butzleri strains and some A. cryaerophilus strains isolated from milk were resistant to amoxicillin‐clavulanic acid and tetracycline. All A. cryaerophilus isolates from milk were susceptible to gentamycin, streptomycin, erythromycin and ciprofloxacin. The distribution of resistance genes in Arcobacter strains in milk shows that all isolates carried tet(O) and blaOXA‐61 genes. Conclusions In conclusion, the results indicate a low recovery rate of Arcobacter spp. in milk and milk products. However, a significant number of Arcobacter strains with putative virulence genes may be potential pathogens for humans and an overall increase in Arcobacter resistance to first‐line antibiotics. These results highlight the need for regular surveillance of Arcobacter strains in milk and milk products in Iran.

Abstract Background Infectious coryza (IC) is an invasive upper respiratory disease caused by Avibacterium paragallinarum that affects birds, particularly chickens. The objective of this study is to isolate, characterize and molecularly identify the bacterium A. paragallinarum in poultry birds, as well as to determine its antibiotic sensitivity and resistance. Methods A total of 10 chickens from four different Iranian farms with typical IC symptoms were used in this study. The nasal swabs were streaked onto chocolate agar plates and blood agar plates and incubated at 37°C in 5% CO2 for 24 to 48 h. As part of the identification of bacteria, bacteriological observations and polymerase chain reaction (PCR) testing are conducted. The antibiotic sensitivity tests were also performed using the disk diffusion method against A. paragallinarum and the prevalence in different farms was determined. Results By using biochemical assays and PCR analyses, seven strains of A. paragallinarum were isolated from samples of four chicken farms with typical IC clinical signs. Most isolates (4/7) showed the typical requirement for nicotinamide adenine dinucleotide (NAD) and an enriched CO2 atmosphere for growth. Three of the seven strains of A. paragallinarum were found to be novel NAD‐independent under anaerobic conditions. There was one biochemical biovar identified in terms of carbohydrate fermentation patterns, although changes in maltose carbohydrate fermentation patterns were detected in the No. 5 strain. All isolates were sensitive to gentamicin and spectinomycin. Three novel NAD‐independent strains (Nos.1, 5 and 7) were found to be multidrug‐resistant (MDR) and resistant to at least three classes of antibiotics. There was greater antibiotic resistance in the three NAD‐independent isolates than in normal NAD‐dependent bacteria. Conclusion By discovering NAD‐independent forms of A. paragallinarum, these species have a greater range than previously believed. A clear, cautious approach should be taken in diagnosing and possibly controlling IC.

Abstract Background Enterococcus faecalis is considered an opportunistic foodborne pathogen. The present study aimed to assess the prevalence, antimicrobial resistance, virulence characters, and molecular typing of E. faecalis strains isolated from seafood samples. Methods Two hundred and seventy‐six seafood samples were collected. E. faecalis was isolated from samples using bacterial culture. Furthermore, the disk diffusion assessed their antimicrobial resistance. Also, the distribution of virulence factors was determined using polymerase chain reaction (PCR) assay. Random amplified polymorphic DNA (RAPD) method was used for their molecular typing. Results Fifty‐six of 276 (20.2%) seafood samples were contaminated with E. faecalis. Fish harboured the highest contamination rate (30.0%). Isolates harboured the highest resistance rate towards oxacillin (100%), tetracycline (100%), erythromycin (100%), cefoxitin (89.2%), cefazolin (87.5%), trimethoprim‐sulfamethoxazole (85.7%), rifampin (69.6%), clindamycin (69.6%), and gentamicin (64.2%) antimicrobials. Efa (100%), ebpA (89.2%), ebpB (58.9%), ebpC (53.5%), and esp (51.7%) were the most commonly detected virulence factors among E. faecalis isolates. RAPD–PCR analysis showed 11 different molecular clusters considering the closeness of more than 80%. Conclusion Seafood samples were considered reservoirs of virulence and resistant E. faecalis strains. Different molecular clusters of isolates may reflect their diverse sources of contamination.

Abstract Background The correlation between various factors (geographical region, clinical incidence, and host type) and the genomic heterogeneity has been shown in several bacterial strains including Chlamydia abortus. Methods The aim of this study was to survey the predominant types of C. abortus strains isolated from ruminants in Iran by the multiple loci variable number of tandem repeats (VNTR) analysis (MLVA) method. C. abortus infection was evaluated in a total of 117 aborted fetuses by real-time PCR. The isolation was done via the inoculation of the positive samples in chicken embryo and the L929 cell line. Genotyping was carried out by MLVA typing technique. Results Forty samples (34.2%) were detected with C. abortus infection; however, chlamydial infection in ruminants of Charmahal/Bakhtiari (3 bovines and 35 sheep) was higher than that of Khuzestan (2 sheep). All MLVA types (MT1-MT8) were detected in the collected samples from Charmahal/Bakhtiari but only 2 types (MT1 and MT3) were reported in samples from Khuzestan. The main MT type was MT1 (32% of aborted fetuses). Although in this study only 9 cow samples were investigated, they possessed similar clusters to those obtained from sheep (MT1 and MT6). Variation of type in sheep samples (MT1 to MT8) was more than that of bovine samples (MT1, and MT6). Conclusion By this research revealed that C.abortus was responsible for a significant percentage of ruminant abortion in two studied regions. The main MT type was MT1 (32% of aborted fetuses) and also 7 different genotypes were involved in infections. So it is concluded that diversity in C.abortus genotyping is high in two regions.

Objectives: Staphylococcus aureus is one of the most common causes of food poisoning in humans. Various methods including genotyping based on protein A (Spa typing) and PCR-based methods have been used for genetic classification of this bacterium. In the present study, Spa gene tracking was used for genotyping of Staphylococcus aureus isolates.Methods: 100 samples of raw chicken meat were collected from chicken meat supply centers in the market of Chaharmahal and Bakhtiari province. Samples were tested for Staphylococcus aureus bacteria by microbial culture and molecular methods and the presence of Spa gene in strains detected by PCR and enzymatic digestion.Results: Out of the total of 23 isolates of Staphylococcus aureus studied, 6 isolates lacked the Spa gene. In the rest of the isolates, a fragment with a size of about 1100 to 1500 bp was detected, and based on the detected gene fragment, 17 isolates containing the Spa gene were divided into four genotypes I to IV; So that 9 isolates were in SpaI genotype, 3 isolates in SpaII genotype, 3 isolates in SpaIII genotype and 2 isolates in SpaIV genotype.Conclusion: The presence of high genomic diversity in these isolates indicates cross-contamination of contamination and therefore can be prevented from the presence and growth of this bacterium in food by implementing quality control and food safety standards during the production process.

Background and Objectives: Genetic diversity of Mycobacterium tuberculosis clinical isolates from tuberculosis patients in the multiethnic province of Alborz, Iran was assessed. Materials and Methods: A total of 17 isolates in the period of 2012-2013 were collected and subjected to a Multiple-locus variable-number tandem repeat (VNTR) analysis (MLVA) consisted of 6 variable numbers of tandem repeats (VNTRs) including ETR-A, ETR-B, ETR-C, ElTR-D, ETR-E, ETR-F, 5 Mycobacterial Interspersed Repetitive Units including MIRU10, MIRU16, MIRU26, MIRU39, MIRU40, and 1 Queen University of Belfast locus, QUB11. Results: This classified all isolates into 17 distinct MIRU-VNTR types, a reflection of a highly heterogenic population. Within the 12 used VNTR loci, ten proved highly or moderately discriminant according to the calculated HGDI scores. No cluster of isolates was identified in the study panel, giving a clustering rate of 0%, several events of SVL (N=5) and DVL (N=4) and TVL (N=3) were detected. Conclusion: The greater heterogeneity observed here by MLVA-VNTR analysis is most likely due to limited background data in the study region rather than a genuine more heterogeneous population compared to other provinces of the country.

The aim of the present study was to evaluate the presence of N. caninum in stool samples of one hundred sheltered and Indoor dogs in Isfahan province, Iran, by using the PCR method. It is believed that cattle infected by N. caninum, with acute or chronic forms, represent a higher risk of abortion than non-infected cows. The zoonosis aspects of Neosporosis is under investigation and infection with N.caninum in humanis not reported yet. We collected Ninety stool samples from mixed shelter dogs of an animal shelter and ten more stool samples from Indoor dogs with the average age of 1-3 years oldin districts of Isfahan province, Iran. The samples were selected randomly and examined by the PCR technique to analyze the extracted DNA from stool samples, and statistical analysis was performed by using SPSS software. Out of 90 mixed breeds sheltered dogs whose stools were examined by using PCR, 22 samples were positive (16 female dogs and six male dogs). The results of the PCR test were negative in Indoor dogs. The highest presence of N. caninum in stray/sheltered female dogs compared to male and Indoor dogs was found. In this research by the first time, we determined that the prevalence of Neospora caninum is comparatively high in dogs from Isfahan and the middle parts of Iran.

Objective: Influenza virus, which is associated with high level of morbidity and mortality, has been recently considered a public health concern; however, the methods of choice to control and treat it are limited. Our previous study showed anti-influenza virus activity of pomegranate peel extract (PPE). In this study, the mechanism through which PPE acts against influenza virus A/Puerto Rico/8/34 (H1N1; PR8) was investigated. Materials and Methods:Ethyl alcohol extract of pomegranate (Punica granatum L.) peel was prepared, and the action mechanism of PPE in inhibiting influenza replication was studied by time-of-drug-addition assay, virucidal activity, RNA replication, hemagglutination inhibition assay, viral mRNA expression, and western blot analysis. Results: PPE inhibited viral polymerase activity, viral RNA replication, and viral protein expression but could not affect hemagglutination inhibition and virucidal activity. According to time-of-drug-addition assay results, PPE inhibited the virus adsorption and early steps of influenza replication. Conclusion: This study demonstrated that the antiviral effect of PPE on influenza virus is most probably associated with inhibition of viral adsorption and viral RNA transcription.

Abstract Resistant Acinetobacter baumannii isolates are not only known as opportunistic nosocomial bacteria but may also be regarded as emerging bacterial contaminants in foods of animal origins. The present investigation was done to assess the prevalence and antibiotic resistance pattern of A. baumannii isolated from different types of raw meat samples. One hundred and ninety‐four raw meat samples were collected and cultured for A. baumannii isolates. Culture‐positive bacteria were also approved using the loop‐mediated isothermal amplification (LAMP) technique. The disc diffusion method was used for antibiotic susceptibility testing. Out of 194 raw meat samples, 39 (20.10%) were positive for A. baumannii isolates. Ovine raw meat was the most commonly contaminated samples (32.14%). All of the culture‐positive A. baumannii isolates were also approved using the LAMP assay. A. baumannii isolates harboured the highest prevalence of resistance against gentamicin (87.17%), tetracycline (79.48%), erythromycin (74.35%), azithromycin (66.66%), ciprofloxacin (58.97%), trimethoprim/sulphamethoxazole (56.41%) and rifampin (51.28%). The lowest prevalence of resistance was found against imipenem (17.94%) and chloramphenicol (28.20%). Raw bovine, ovine, caprine, camel and poultry meat samples were considered as the important sources of isolates resistant to some of the categories of antimicrobials used to treat infections caused by A. baumannii. Further studies are required to find the exact role of resistant A. baumannii isolates in the dissemination of antibiotic resistance to human population.

The production of biofilms by S. aureus contributes significantly to treatment failures. The present study aims to establish the relationship between biofilm formation and antibiotic resistance and adhesion genes in Staphylococcus aureus strains isolated from raw cow milk in Shahrekord, Iran. A total of 90 samples of raw cow’s milk were collected. Presumptive S. aureus strains were obtained using Baird-Parker plates after enrichment in tryptone soy broth, and final colonies were selected from brain heart infusion. Additional tests such as coagulase were done, and the identification was confirmed by the detection of the aroA gene. Biofilm producing strains were screened using a spectrophotometry method applied to microplates. Crystal violet staining was used to quantify the formation of biofilm. An antibiotic susceptibility test was performed using the Kirby–Bauer disc diffusion method. PCR was used to detect several biofilm and antibiotics resistance related genes. The chi-square test and Fisher’s exact test were used to establish a statistically significant relationship between biofilm reaction and antibiotic resistance (p value

Abstract Background Resistant Staphylococcus epidermidis strains are considered to be one of the major causes of human clinical infections in hospitals. The present investigation was done to study the pattern of antibiotic resistance and the prevalence of virulence and antibiotic resistance genes amongst the S. epidermidis strains isolated from human hospital infections. Methods One hundred hospital infectious samples were collected and S. epidermidis strains were identified using culture and biochemical tests. Isolated strains were subjected to disk diffusion and PCR. Results Forty-six out of 100 hospital infectious samples (46%) were positive for S. epidermidis. S. epidermidis strains harbored the highest prevalence of resistance against penicillin (95.65%), tetracycline (91.30%), erythromycin (82.60%), cefazolin (78.26%), and trimethoprim-sulfamethoxazole (73.91%). All S. epidermidis strains had resistance against at least three different types of antibiotics, while the prevalence of resistance against more than seven types of antibiotics was 17.39%. AacA-D (69.56%), tetK (56.52%), mecA (45.65%), msrA (39.13%), and tetM (39.13%) were most commonly detected antibiotic resistance genes. The prevalence of vatC (4.34%), ermA (8.69%), vatA (8.69%), vatB (13.04%), ermC (13.04%), and linA (10.86%) were lower than other detected antibiotic resistance genes. ClfA (32.60%), agrIII (17.39%), and etB (13.04%) were the most commonly detected virulence factors. Conclusions The presence of virulent and multi-drug resistance S. epidermidis strains showed an important public health issue in hospitals.

Abstract Background Trueperella pyogenes is one of the most clinically imperative bacteria responsible for severe cases of mastitis and metritis, particularly in postpartum dairy cows. The bacterium has emergence of antibiotic resistance and virulence characters. The existing research was done to apprise the phenotypic and genotypic evaluation of antibiotic resistance and characterization of virulence factors in the T. pyogenes bacteria of bovine mastitis and metritis in postpartum cows. Methods Two-hundred and twenty-six bovine mastitic milk and 172 uterine swabs were collected and transferred to laboratory. Samples were cultured and T. pyogenes isolates were subjected to disk diffusion and DNA extraction. Distribution of virulence and antibiotic resistance genes was studied by PCR. Results Thirty-two out of 226 (14.15%) mastitic milk and forty-one out of 172 (23.83%) uterine swab samples were positive for T. pyogenes. Isolates of mastitic milk harbored the highest prevalence of resistance toward gentamicin (100%), penicillin (100%), ampicillin (90.62%), amoxicillin (87.50%) and trimethoprim-sulfamethoxazole (87.50%), while those of metritis harbored the highest prevalence of resistance toward ampicillin (100%), amoxicillin (100%), gentamicin (97.56%), penicillin (97.56%) and cefalexin (97.56%). AacC, aadA1, aadA2 and tetW were the most generally perceived antibiotic resistance genes. All bacteria harbored plo (100%) and fimA (100%) virulence factors. NanP, nanH, fimC and fimE were also the most generally perceived virulence factors. Conclusions All bacteria harbored plo and fimA virulence factors which showed that they can use as specific genetic markers with their important roles in pathogenicity of T. pyogenes bacteria. Phenotypic pattern of antibiotic resistance was confirmed by genotypic characterization of antibiotic resistance genes.

Acinetobacter genus belongs to a group of Gram-negative coccobacillus. These bacteria are isolated from human and animal origins. Antimicrobial agents play a vital role in treating infectious diseases in both humans and animals, and Acinetobacter in this regard is defined as an organism of low virulence. The current study aimed to evaluate antibiotic resistance properties and virulence factor genes in Acinetobacter baumannii strains isolated from raw animal meat samples. Fresh meat samples from 124 sheep, 162 goat, and 95 camels were randomly collected from Isfahan and Shahrekord cities in Iran. Most A. baumannii strains isolated from sheep meat samples represented fimH (82.35%), aac(3)-IV (78.43%), sul1 (78.43%) and Integron Class I (96.07%) genes. Moreover, more than 50% of A. baumannii strains isolated from sheep samples were resistant to streptomycin (54.90%), gentamycin (74.50%), co-trimoxazole (70.58%), tetracycline (82.35%), and trimethoprim (62.74%). Current findings revealed significant association between the presence of fimH, cnfI, afa/draBC, dfrA1, sulI, aac(3)-IV genes in sheep samples. Furthermore, significant association was observed between fimH, cnfI, sfa/focDE and dfrA1genes in goat meat samples. In sheep meat samples, significant differences were identified in resistance to gentamicin, tetracycline, and co-trimoxazole in comparison with other antibiotics. Finally, there were statistically significant differences between the incidences of resistance to gentamicin, tetracycline, and co-trimoxazole in comparison with other antibiotics in all strains. In conclusion, the presence of virulence factors and antibiotic resistance in A. baumannii strains isolated from animal meat samples showed that animals should be considered as a potential reservoir of multidrug-resistant A. baumannii.

Objective & Aim: Escherichia coli includes a wide range of different strains in ecosystems with huge diversity in their genomes. Some strains cause serious diseases, such as Urinary Tract Infections (UTI). Uropathogenic Escherichia coli (UPEC) is the most frequent agent causing UTI in humans. The aim of this study was to investigate the prevalence of O-serogroups among E. coli isolated from patients with UTI in Isfahan province and genetic classification of O25 serogroup isolates by ERIC-PCR method. Materials and Methods: 226 urine samples from patients with UTI were collected from hospitals in Isfahan province. E. coli isolates were identified using standard methods. Serogroups of these isolates were determined by PCR method and genetic classification of isolates with serogroup O25 was performed using ERIC-PCR method. Results: A total of 96 E. coli strains were isolated from the urine samples. The most common types of O antigens were O25(37.5%), O21(9.37%) and O6(8.33%). The genetic classification of isolates with serogroup O25 showed 25 different profiles among these 36 isolates Conclusion: ERIC-PCR technique is a quick, sharp and cost-effective method. It seemed that this technique to be a good approach for molecular typing of E. coli strains isolated from different urinary tract infections sources.

Abstract Background Acinetobacter baumannii strains with multiple antimicrobial resistance are primarily known as opportunistic nosocomial bacteria but they may also be regarded as emerging bacterial contaminants of food samples of animal origin. Here we aimed to study the molecular characteristics of the A. baumanni strains isolated from raw meat samples. Methods A total of 22 A. baumanni strains were isolated from 126 animal meat samples and were genotyped by ERIC-PCR method and by PCR detection of their virulence and antimicrobial resistance determinants. A. baumannii strains with 80% and more similarities were considered as one cluster. Results Sixteen different genetic clusters were found amongst the 22 A. baumanni strains. Of the 22 strains, 12 (54.54%) had similar genetic cluster. A. baumannii strains exhibited the highest percentage of resistance against tetracycline (90.90%), trimethoprim (59.09%), cotrimoxazole (54.54%) and gentamicin (50.00%). TetA (81.81%), tetB (72.72%), dfrA1 (63.63%), aac(3)-IV (63.63%), sul1 (63.63%) and aadA1 (45.45%) were the most commonly detected antibiotic resistance genes. FimH (81.81%), afa/draBC (63.63%), csgA (63.63%), cnf1 (59.09%), cnf2 (54.54%) and iutA (50.00%) were the most commonly detected virulence factors. A. baumannii strains isolated from the chicken meat samples had the highest similarities in the genetic cluster. Conclusions A. baumannii strains with similar genetic cluster (ERIC-Type) had the same prevalence of antibiotic resistance, antibiotic resistance genes and virulence factors. Genetic cluster of the A. baumannii strains is the main factor affected the similarities in the genotypic and phenotypic properties of the A. baumannii strains.

Background & Aim: Klebsiella pneumoniae is one of the most common gram-negative bacteria in the development of nosocomial infections, in particular urinary tract infections, which has been resistant to antibiotics in recent years. The aim of this study was to determine the pattern of antibiotic resistance in the most common capsule types of this bacterium in Zarinshahr city of Isfahan. Material and Methods: 29 strains of Klebsiella pneumoniae isolated from urinary tract infections in patients admitted to different parts of Zarinshahr Hospital in summer 2016 to summer 2017 were selected. After confirmation of phenotypic and genotype and determination of capsule types in them, antibiotic resistance pattern in isolates was determined using Kirby-bauer method, according to the CLSI standard, on the Muller Hinton Agar, 13 antibiotics were determined. Frequency of antibiotic resistance gene encoding genes including tetA, cmlA, Cat1, blaSHV, sul1, aac (3) -IV, aadA 1, qnr CITM, dfrA1, and tetB genes in isolates was determined by PCR method. Results & Conclusion: Serotype K2 with 74.51% frequency was the most commonly known capsule serotype known in isolates. All isolates had multiple antibiotic resistance and in addition to penicillin, their antibiotic resistance was the highest (10.93%) and tetracycline (44.30%) respectively. The tetA and sul1 genes with the frequency of 86.75% and 41.72% were the most common, and the two cat1 and cm1A genes with a frequency of 89.60% and 44.10% were the least common antibiotic resistance genes in Klebsiella pneumoniae strains isolated from urinary tract infections.

Introduction: Diabetes is the most common and important diseases in the world, and diabetic patients are at high risk of infection. Due to the high prevalence of diabetes and risks of urinary tract infections, ccauses of urinary tract infection and the proper way to treat it acutely felt Material and methods: In this study, 353 urine samples of diabetic patients cultured and by using biochemical tests were examined. After DNA extraction, PCR test for definitive diagnosis of bacteria and the antibiogram test was carried out. Results: Urinary tract infection in diabetic patients 28.3% was reported. Asymptomatic bacteriuria 22.1% and symptomatic bacteriuria 6.22% was reported. The most common bacteria that cause urinary tract infections in patients were respectively Escherichia coli, Klebciella pneumonia, Proteus, Staphylococcus saprophyticus, Acinetobacter, Citrobacter, Enterobacter, Pseudomonas aeruginosa and Providencia. Conclusion: Given that bacterial population of urinary tract infections in diabetic patients, similar to non-diabetic patients, so antibiotic treatment in diabetic patients is alike with and non-diabetic patients. Keywords: bacteriuria, Diabetes, urinary tract infection, antibiotic resistance, PCR.

Background and Objectives: Staphylococcus epidermidis is one of the effective factors causing nosocomial infections. This study was performed to investigate the antibiotic resistance pattern in the methicillin-resistant S. epidermidis strains isolated from clinical samples in Isfahan Province. Methods: In this descriptive cross-sectional study, 150 isolates of S. epidermidis were isolated from detected from the patients hospitalized in hospitals and treatment centers of Isfahan City. The antibiotic resistance pattern was evaluated by disk diffusion method. The presence of the gene encoding antibiotic resistance to methicillin (mec A) in the isolates were investigated using PCR method. Data were analyzed with Chi-square and Fisher's exact statistical tests. Results: In this study, most isolates were related to urinary tract infections. The highest resistance was reported to penicillin (98.9%), erythromycin (89.4%), ciprofloxacin (77.7%), clindamycin (65.9%), tetracycline (63.2%), and meticillin (54%). None of the strains showed resistance to vancomycin and linezolid. Molecular studies indicated the presence of mecA gene in 76% of the studied isolates. Conclusion: According to the results of this study, vancomycin and linezolid antibiotics can be the best choice of treatment for infections caused by S. epidermidis. Also, high resistance of S. epidermidis can be a serious warning for increased multiple antibiotic resistance. Molecular studies are indicative of high sensitivity of molecular methods in the investigation of methicillin-resistant isolates.

Abstract Background: Biofilm formation is one of the pathogenicity factors of Staphylococcus aureus that can help the bacteria to stick to the other surface and also increase antibiotic resistance pattern. This study aimed to investigate the phenotypic and genotypic indices for formating biofilm in Staphylococcus aureus isolates isolated from infectous samples. Materials and Methods: 250 Staphylococcus aureus strains isolated from hospital infections were selected. Antibiotic resistance pattern was determined by using disk diffusion method. The ability of biofilm formation was investigated by molecular and phenotypic method. Results: In this study, 73.5% of isolates were able to bind strongly, 5.33% had the ability of medium connection and 15.4% had the ability of weak connection in biofilm production. The frequency of icaC and icaB genes were 67.3% and 63.2%, respectively. 92.2% of biofilm producing isolates have mecA gene. Conclusion: The spread of antibiotic resistance in isolates especially isolates that produce biofilm will create serious problems in the hospital therapeutic wards.

Background and Objectives: Enzootic abortion of ewes (EAE) is caused by infection of sheep and goats by Chlamydia abortus bacterium. Chlamydial abortion in bovine could occur by Chlamydia abortus, Chlamydia psittaci and Chlamydia pecorum. C. psittaci is the causative agent of psittacosis or ornithosis disease in humans and birds. It also causes acute pneumonia in cattle and sheep. The present study aimed at surveying the role of chlamydial agents in ruminants abortion. Materials and Methods: A total of 117 aborted material samples (Cotyledon, liver, spleen, and abomasal contents of fetus) from 9 cattle and 100 sheep in Shahr-e-Kord and 8 sheep from Bagh-e-Malek were collected from different herds with abortion history during the lambing periods from 2014 to 2016. After DNA extraction, the samples were tested by species-specific PCR to detect C. abortus, C. pecorum and C. psittaci. Results: Out of 117 clinical sample (108 sheep and 9 cattle), chlamydial infection was detected in 66 (56.41%) samples by Chlamydiales order-specific primers. A total of 24 (36.36%) and 24 (36.36%) samples indicated positive forms of C. abortus and C. psittasi infections, respectively. Only 1 (1.5%) C. pecorum was identified from cattle using nested PCR during this study. Among 66 Chlamydiales- positive samples, 20 (30.30%) samples with coinfection of C. abortus and C. psittaci were detected, however, infection of 3 species was not detected in the samples. Conclusion: Because of the high percentage of chlamydial infection in these regions and probability of coinfection, conducting epidemiological studies on the role of different animals is highly recommended.

Introduction: Acinetobacter baumannii is a gram-negative coccobacill that has a great distribution in the nature and is considered as one of the important causes of hospital infections. Due to the antibiotic resistances in this bacterium several problems in the successful treatment of patients and subsequently their mortality have been occurred. The present study was carried out in order to detect the most prevalent antibiotic resistance genes in Acinetobacter baumannii strains isolated from the hospital infections. Materials and methods: This descriptive study was carried out on 121 strains of Acinetobacter baumannii isolated from clinical samples of two hospitals of Tehran city. After identifying isolates using the biochemical tests, the antibiotic resistance pattern of them was done using the disk diffusion and molecular (in order to identify the antibiotic resistance genes) methods. Results: Of 121 strains of Acinetobacter baumannii isolated from infectious samples, the most commonly detected antibiotic resistance was against tetracycline and the most sensitivity was achieved against chloramphenicol, nitrofurantoin and meropenem by distribution of 1.65 %. The distribution of dfrA1, tet(A), aac(3)-IV, sul1, tet(B), aadA1, qnr, CITM, blaSHV, sim, vim, oxa-58-like. Oxa-24-like, imp, oxa-51-like, oxa-23-like, cat1 and cmlA were 79 (65.27 %), 71 (58.67 %), 68 (56.19 %), 67 (55.37 %), 44 (36.36 %), 41 (33.88 %), 29 (23.96 %), 28 (23.14%), 24 (19.83 %), 17 (14.04 %), 16 (13.22 %), 14 (11.57 %), 12 (9.91 %), 10 (8.26 %), 9 (7.43 %), 8 (6.61 %), 5 (4.13 %) and 3 (2.47 %), respectively. Discussion and conclusion: Multiple antibiotic resistance in studied isolates the use of molecular techniques in the antibiogram test to select the most effective antibiotic treatment of infections and the importance of continued antibiotic surveillance that will provide succession in the efforts of infection control programs for the future.

Background and Aim: Shiga toxin-producing Escherichia coli (STEC) may also be referred to as Escherichia coli pathotypes, since E. coli serogroups O26 and O157 are frequently implicated in outbreaks of diarrhea in children. This study aimed to analyze the clone relationship of Shiga toxin-producing E. coli serogroups O157 and O26 isolated from diarrhea in children less than 60 months by Multilocus Sequence Typing (MLST) method. Materials and Methods: A total of 20 Shiga toxins-producing E. coli (STEC strains were selected from two serogroups O26 and O157 isolated from diarrheic children, and the PCR products from amplification of seven housekeeping genes were sequenced in them. The nucleotide sequences of each gene in each isolate were analyzed, then queried to the MLST database and, in addition, determination of allele-specific of each gene were determined of sequence types (ST). Results: A total of 3 clones ST10, ST11 and ST21 were identified from 20 isolates, which identified three gene clusters A, B and C, respectively. Conclusions: Despite of the different ST were found in our isolates studied. There was no a high genetic diversity among the two serogroup O26 and O157 isolates, which indicates the clone relationship between E. coli isolates circulating in Tehran.

Lack of proper hygiene and using from low quality raw materials cause high presence of food-borne pathogens in ready to eat foods. Shiga toxin producing Escherichia coli is one of the most common cause of food-borne diseases in the world. The present research was done to study the prevalence and distribution of virulence factors in the STEC strains isolated from various types of ready to eat food samples. Seven-hundred and twenty food samples were collected and cultured. Isolated E. coli bacteria were approved another time using the 16S rRNA-based PCR amplification. Approved strains were subjected to multiplex PCR for identification of putative virulence factors. Twenty-six out of 720 food samples (5.20%) were positive for E. coli. Salad (15%), candy (12.50%) and barbecue (10%) were the most commonly contaminated. Prevalence of STEC strains was 2.63%. Prevalence of EHEC and AEEC subtypes were 36.84% and 52.63%, respectively. EHEC strains harbored all three stx1, eae and ehly genes. High presence of EHEC strains besides the considerable distribution of multiple virulence factors showed an important public health issue regarding the consumption of ready to eat foods.

Introduction : Staphylococcus aureus is considered as one of pathogenic agents in humans, that engages different body parts including respiratory system and causes to spend lots of costs and extending patient’s treatment period. This study which is performed to separate and investigate the pattern of antibiotic resistance in Staphylococcus aureus isolates from upper respiratory system infections in Shahrekord. Materials and methods: This study was done by sectional-descriptive method On 200 suspicious persons to the upper respiratory system infections who were referred to the Imam Ali clinic in Shahrekord in 2012. After isolation of Staphylococcus aureus from cultured nose discharges, antibiotic resistance genes were identified by polymerase chain reaction (PCR) by using defined primer pairs . Results : Among 200 investigated samples in 60 cases (30%) Staphylococcus aureus infection (by culturing and PCR method) was determined. Isolates showed the lowest amount of antibiotic resistance to vancomycin (0.5%) and the highest amount of resistance to the penicillin G and cefotaxime (100%). mecA gene (encoding methicillin resistance) with frequency of 85.18% and aacA-D gene (encoding resistance to aminoglycosides) with frequency of 28.33% showed the highest and lowest frequency of antibiotic resistance genes coding in Staphylococcus aureus isolates respectively . Discussion and conclusion : Notable prevalence of resistant Staphylococcus aureus isolates in community acquired respiratory infections, recommend continuous control necessity to impede the spreading of these bacteria and their infections.

Introduction: Cage birds can harbor human pathogens and contribute to the transmission and spread of drug resistant infectious agents to human. Since many people are interested in keeping cage birds, present study was conducted in cage birds from Shahrekord to investigate the beta-lactam antibiotics resistant E. coli and molecular detection of E. coli O157:H7 that is responsible for outbreaks of human intestinal diseases and fatal haemolytic-uraemic syndrome worldwide. Materials and methods: Altogether 256 samples of cage birds (lovebirds, quails, nightingales, parrots, mynahs, goldfinchs, finches, kingbirds, peacocks, and pheasants) faeces were collected with sterile cotton swabs from different areas of Shahrekord, Iran. Swabs were placed directly into Tryptone Soya Broth (TSB). In the laboratory, samples were streaked onto MacConkey agar and also Sorbitol MacConkey agar as selective plating media. Then, antibiogram tests were performed using disc diffusion method. Suspected colonies to E. coli O157:H7 were tested by polymerase chain reaction (PCR). Results: E. coli was isolated from 31 (12.1%) out of 256 the samples. Resistance of isolates to Imipenem, Cefotaxime, Cefixime, Cefalexin, Amoxicillin, Penicillin G and Oxacillin was 0, 3.2, 16.1, 90.3, 100, 100 and 100% respectively. E. coli O157:H7 was not found in any samples. Discussion and conclusion: Although cage birds were not sourcee or carriers of E. coli O157:H7 in the studied region, they harbored beta-lactam antibiotics resistant E. coli and could be an important component of drug-resistant infections transmission from cage-birds to human, especially to kids and can pose a potential risk to human health. For this reason, it is recommended to make pet birds owners and general public aware of potential dangers of cage bird keeping.

Introduction: Chlamydophila felis is one of the most common pathogens isolated from ocular discharges in domestic cats. The aim of the present study was to detect this microorganism in ocular discharges collected from domestic cats in Tehran and Isfahan cities Materials and methods: From a total of 224 domestic cats, ocular swabs were collected and DNA was extracted. Samples were studied using the Polymerase Chain Reaction method and their products were analyzed using agarose gel. Results: From a total of 224 samples studied, 40 samples (17.85%) were infected with Chlamydophila felis which were diagnosed as positive in PCR test. Discussion and conclusion: According to the difficulties and time-consuming process of isolation of Chlamydophila felis in laboratory culture media, the PCR technique has been suggested as a rapid and safe method for detection of this organism in clinical samples.

Background and Objectives: Feline herpesvirus-1, feline calicivirus and Chlamydophila felis are the main causes of feline upper respiratory tract disease. This study was conducted to identify of FeHV-1, FCV and C. felis infections in domestic cat population and also to estimate the prevalence of each specific infection in Iran. Materials and Methods: The ocular conjunctiva and oropharyngeal specimens obtained from 80 cats were examined using PCR and reverse transcription PCR. Results: FeHV-1 was detected in 23 (28.8%), FCV in 2 (2.5%) and C. felis in 16 (20%) cats. Twelve cats(15%) had co-infection with 2 or 3 of the mentioned pathogens. Ocular lesions were the most common clinical signs in the FeHV-1 and C. felis infections whereas respiratory lesions were more observed with the FCV infections. It seems that there is an age-related tendency in the infected cats, meaning that the age of the C. felis positive cats was less than those with FeHV-1 and FCV infections. Conclusion: These results confirm the presence and show the prevalence of three major pathogens associated with upper respiratory tract disease for the first time in Iran.

Introduction: Pathogens can be transmitted to the humans through the consumption of contaminated meat and thus causing disease. Shiga-toxin-producing Escherichia coli can cause mild watery diarrhea to more serious complications of hemorrhagic colitis, and hemolytic uremic syndrome to even death. Present study was conducted to detect Shiga toxin-producing Escherichia coli from sheep meat (lamb) in ChaharmahalvaBakhtiari, Iran. Materials and methods: 90 Escherichia coli isolates from sheep meat in ChaharmahalvaBakhtiari were evaluated to investigate stx1, stx2 and eaeA genes by multiplex PCR.Results: The rate of stx1 and eaeA-positive Escherichia coli isolates were 11.11% (10/90) and 8.88% (8/90), respectively. Stx2 gene was not found in any isolate.Discussion and conclusion: Lamb harbored Shiga-toxin-producing E. coli and could be a component of Shiga-toxin-producing E. coli transmission from lambs to the humans and can pose a risk to human health in the region.

This study was carried out in order to investigate the presences of Bacillus cereus and its enterotoxigenic genes in infant foods in Isfahan, Iran. Overall 200 infant foods with various based were collected and immediately transferred to the laboratory. All samples were culture and the genomic DNA was extracted from colonies with typical characters of Bacillus cereus. The presences of enterotoxigenic genes were investigated using the PCR technique. Eighty-four of two hundred samples (42%) were found to be contaminated with B. cereus with a ranges of 3 × 101–9.3 × 101 spore per gram sample. Totally, entFM had the highest (61.90%) incidences of enterotoxigenic genes while hblA had the lowest (13.09%) incidences of enterotoxigenic genes. Overall, 6.7% of B. cereus isolates had all studied enetrotoxigenic genes while 25.5% of B. cereus strains had all studied enetrotoxigenic genes expectance bceT gene. Thisstudyisthe first prevalence report of B. cereus and its enterotoxigenic genes in infant foods in Iran. Results showed that the infant food is one of the main sources of enterotoxigenic genes of B. cereus in Iran. Therefore, the accurate food inspection causes to reducing outbreak of diseases.

The aim of this study was to detect the virulence factors, serogroups, and antibiotic resistance properties of Shiga toxin-producing Escherichia coli, by using 268 bovine mastitic milk samples which were diagnosed using California Mastitis Test. After E. coli identification, PCR assays were developed for detection of different virulence genes, serogroups, and antibiotic resistance genes of Escherichia coli. The antibiotic resistance pattern was studied using disk diffusion method. Out of 268 samples, 73 (27.23%) were positive for Escherichia coli, and, out of 73 positive samples, 15 (20.54%) were O26 and 11 (15.06%) were O157 so they were the highest while O111 was not detected in any sample so it was the lowest serogroup. Out of 73 STEC strains, 11 (15.06%) and 36 (49.31%) were EHEC and AEEC, respectively. All of the EHEC strains had stx1, eaeA, and ehly, virulence genes, while in AEEC strains stx1 had the highest prevalence (77.77%), followed by eaeA (55.55%). Totally, aadA1 (65.95%) had the highest while blaSHV (6.38%) had the lowest prevalence of antibiotic resistance genes. The disk diffusion method showed that the STEC strains had the highest resistance to penicillin (100%), followed by tetracycline (57.44%), while resistance to cephalothin (6.38%) was the lowest.

The aims of the current study were to detect the virulence factors and antibiotic resistance of Shiga toxin-producing E. coli, in animal milk and dairy products in Iran. After E. coli dentification with culture method, PCR assay were developed for detection of pathogenic genes, serotypes and antibiotic resistance genes of E. coli. Results showed that out of 719 samples, 102 (14.18%) were confirmed to be positive for E. coli and out of 102 positive samples, 17.64% were O26 and 13.72% were O157 and 1.96% were O91 and 1.96% were O145 serotypes. Totally, the prevalence of stx1 and papA genes were the highest while the prevalence of sfaS and fyuA were the lowest in the positive samples. PCR results showed that tetA, tetB were the highest (64.70%) and aac(3)-IV were the lowest (27.45%) antibiotic resistant genes in E. coli positive samples. Our study indicated that the isolated E. coli trains in these regions had a highest antibiotic resistance to tetracycline (58.82%) and the lowest to nitrofurantoin (3.92%). tetA gene and E. coli O157 serotype had highest and aac(3)-IV gene, and E. coli O145 serotype had a lowest frequency rates of antibiotics resistance genes, in the region.