Dermal Exposure to Vesicating Nettle Agent Phosgene Oxime: Clinically Relevant Biomarkers and Skin Injury Progression in Murine Models.

Phosgene oxime (CX), categorized as a vesicating chemical threat agent, causes effects that resemble an urticant or nettle agent. CX is an emerging potential threat agent that can be deployed alone or with other chemical threat agents to enhance their toxic effects. Studies on CX-induced skin toxicity, injury progression, and related biomarkers are largely unknown. To study the physiologic changes, skin clinical lesions and their progression, skin exposure of SKH-1 and C57BL/6 mice was carried out with vapor from 10 µl CX for 0.5-minute or 1.0-minute durations using a designed exposure system for consistent CX vapor exposure. One-minute exposure caused sharp (SKH-1) or sustained (C57BL/6) decrease in respiratory and heart rate, leading to mortality in both mouse strains. Both exposures caused immediate blanching, erythema with erythematous ring (wheel) and edema, and an increase in skin bifold thickness. Necrosis was also observed in the 0.5-minute CX exposure group. Both mouse strains showed comparative skin clinical lesions upon CX exposure; however, skin bifold thickness and erythema remained elevated up to 14 days postexposure in SKH-1 mice but not in C57BL/6 mice. Our data suggest that CX causes immediate changes in the physiologic parameters and gross skin lesions resembling urticaria, which could involve mast cell activation and intense systemic toxicity. This novel study recorded and compared the progression of skin injury to establish clinical biomarkers of CX dermal exposure in both the sexes of two murine strains relevant for skin and systemic injury studies and therapeutic target identification. SIGNIFICANCE STATEMENT: Phosgene oxime (CX), categorized as a vesicating agent, is considered as a potent chemical weapon and is of high military and terrorist threat interest since it produces rapid onset of severe injury as an urticant. However, biomarkers of clinical relevance related to its toxicity and injury progression are not studied. Data from this study provide useful clinical markers of CX skin toxicity in mouse models using a reliable CX exposure system for future mechanistic and efficacy studies.

Bovine coronavirus in neonatal calf diarrhoea in Iran.

Partial gene sequencing for the bovine coronavirus at the World Genebank is available for many countries, which are distributed unevenly in five continents, but so far, no sequencing of strains has been recorded in Iran. One hundred ninety-four stool samples from calves with diarrhoea less than one-month old were collected from five different geographical regions of country in order to detect coronavirus and characterize it if coronavirus was found. Samples were screened for the presence of BCoV by using a commercially available ELISA kit. Furthermore, RT-PCR was carried out on positive samples for confirmation of the presence of N and S specific genes. Sequencing and phylogenetic analysis was carried out following RT-PCR tests. 7.2% of samples, were positive for BCoV and all stool samples from the South-West, Northeast and West regions of Iran were negative. The results showed that all the strains of coronavirus identified in Iran were completely in independent clusters and that they did not stand in the same cluster as any of the strains identified in other parts of the world. The strains from Iran were quite different from strains in other parts of the world but from the point of similarity these viruses showed some similarities to the European strains, such as those found in France, Croatia, Denmark and Sweden.

Detection and molecular characterization of bovine leukemia virus in various regions of Iran.

Purpose. Bovine leukemia virus (BLV) infects cattle worldwide, imposing an economic impact on the dairy cattle industry. The purpose of this study was to evaluate the molecular epidemiology of BLV in Iran.Methodology. Blood samples taken from 280 cows aged over 2 years old from 13 provinces of Iran were used for leukocyte count and blocking ELISA. Genomic DNA was extracted from the peripheral blood leukocytes of BLV-infected samples and fetal lamb kidney cells to perform PCR of partial env, rex and tax genes and long-terminal-repeat region. The PCR products were sequenced, the phylogenetic tree of each gene was constructed, and nucleotide and amino acid sequence pair distances were calculated.Results. The frequency of BLV infection was 32.8 % among animals and was 80 % among provinces. In BLV seropositive animals, the rate of persistent lymphocytosis was 36.9 %. The constructed phylogenetic trees showed the presence of two BLV genotypes (1 and 4) in Iranian strains. As previous studies, our results showed that the env gene was more variable than previously thought, the Rex protein could withstand more amino acid changes compared to the Tax protein, and no significant differences were observed in average changes of the nucleotide of these genes between clinical stages.Conclusions. Our data indicates an increase in the frequency of this infection in Iran. This is the first study report of the presence of BLV genotype 4 in Iranian farms. These findings may have an important role in the control and prevention of BLV infection in Iran and other countries.

Bovine leukemia virus detected in the breast tissue and blood of Iranian women.

BACKGROUND: Breast cancer is one of the most common cancers in the world particularly among Iranian women. Bovine leukemia virus (BLV) is an enzootic, exogenous, and oncogenic retrovirus that causes B-cell leukosis in 1-5% of infected cattle. The current study aimed at evaluating the correlation between BLV infection and breast cancer in an Iranian population. MATERIALS AND TECHNIQUES: A total of 400 samples including 200 breast cancer-suspected tissue samples and 200 blood samples of women without breast cancer, were collected from July 2017 to October 2018 from women referred to two general hospitals in Qom Province, Iran. The nested PCR technique was performed to determine the presence of tax and gag gene of BLV in the collected samples. RESULTS: Out of 200 breast cancer-suspected tissue samples, 172 samples were malignant in terms of pathology. Other samples were reported as non-malignant and non-tumor. Based on nested PCR technique, tax and gag genes of BLV were detected in 30% and 8% of breast cancer-suspected tissue samples, respectively. The frequency of BLV in blood samples collected from women without breast cancer was 16.5% (33/200). CONCLUSION: It seems that human breast cancer and BLV infection in cattle could be associated using nested PCR technique.

Analysis of antigen conservation and inactivation of gamma-irradiated avian influenza virus subtype H9N2.

Avian influenza (AI) A subtype H9N2 virus belongs to Orthomyxoviridae family and causes low-pathogenic disease AI. The use of gamma-irradiated viral antigens has been developed in the production of effective vaccines. In this research, LPAIV H9N2 strain, A/Chicken/IRN/Ghazvin/2001, was multiplied on SPF eggs and irradiated by a Nordian gamma cell instrument. Irradiated and non-irradiated AI virus (AIV) samples were titrated by EID50 method and hemagglutinin (HA) antigen was analyzed by HA test as the WHO pattern method. Infectivity of irradiated virus was determined by egg inoculation method during four blind cultures. The results showed that after increasing the dose of gamma radiation, virus titer gradually decreased. D10 value and optimum dose for complete virus inactivation were calculated by dose/response curve, 3.36 and 29.52 kGy, respectively. In addition, HA antigenicity of gamma-irradiated virus samples from 0 to 30 kGy was not changed. The results of safety test for gamma-irradiated AIV samples showed complete inactivation with gamma ray doses 30 and 35 kGy, without any multiplication on eggs after four blind cultures. According to the results of HA antigen assay and safety test, the gamma-irradiated and complete inactivated AIV subtype H9N2 is a good candidate as an inactivated immunogenic agent for poultry vaccination.

Co-circulation of three clusters of 793/B-like avian infectious bronchitis virus genotypes in Iranian chicken flocks.

Avian infectious bronchitis (IB) is an acute and highly contagious viral disease causing severe economic losses in the poultry industry. The 793/B IB virus is an important infectious bronchitis virus (IBV) genotype currently circulating in several countries, including Iran. One hundred confirmed IBV samples (between 2014 and 2015; from 15 provinces in Iran) were selected for genotyping based on S1 sequencing. After phylogenetic analysis, it was found that 30% of the IBV isolates belonged to the 793/B genotype. Results showed that the Iranian 793/B-like IBV isolates could be divided in to three clusters: 4/91-like (50%), 1/96-like (40%), and IB88-like (10%). The sequence similarity between Iranian 793/B-like IBV isolates is 87.69%-100%. The highest identity is between the 4/91 and IB88 clusters (96.38%), and the lowest similarity is between the 1/96 and IB88 clusters (87.62%). This study provides a comprehensive analysis of 793/B-type IBV in Iran and characterization of IBV molecular epidemiology in the country.

Pathogenicity study of Iranian genotype of avian infectious bronchitis virus (IR-1).

Avian infectious bronchitis (IB) is a major cause of economic losses in poultry industry. The IB virus primarily affects respiratory tract, but various strains differ in their tropism for other target organs such as kidney and alimentary tract. The objective of this study was to estimate the pathogenicity of Iranian IBV variant (IR-1), which is limited exclusively to Iran. Specific pathogen free chicks were inoculated intranasally. Sera, fecal swabs and different tissue samples were collected on different days post infection (DPI). Clinical signs, gross pathology and histological changes were recorded. The viral load was quantified in the RNA extractions from different tissue samples using real-time PCR. Anti-IBV antibodies were detected in serum samples. The IgG antibody were found on 21 and 28 DPI. Severe histological lesions were observed in the trachea and lung while the lesions in kidney were appeared to be milder. Viral RNA was detected in all tested tissues from 1 DPI to the last day of the experiment. The highest viral load was measured in the trachea and feces on 1st and 5th DPI, respectively. It can be concluded the IR-1 had broad tropism for respiratory tract, digestive system, and renal tissue, reflecting its epitheliotropic nature, but it caused the most severe lesions in the respiratory tract. This was the first pathogenicity study of Iranian IR-1 IBV. Further knowledge of IBV pathogenesis provides the groundwork to inform more effective prevention practices.

The first comprehensive molecular detection of six honey bee viruses in Iran in 2015-2016.

At least 18 viruses have been reported in the honey bee (Apis mellifera L.). However, severe diseases in honey bees are mainly caused by six viruses, and these are the most important in beekeeping. These viruses include: deformed wing virus (DWV), acute bee paralysis virus (ABPV), chronic bee paralysis virus (CBPV), sacbrood virus (SBV), kashmir bee virus (KBV), and black queen cell virus (BQCV). In this study, we evaluated 89 Iranian honey bee apiaries (during the period 2015-2016) suffering from symptoms of depopulation, sudden collapse, paralysis, or dark coloring, by employing reverse transcription-PCR. Samples were collected from four regions (Mazandaran, Hormozgan, Kurdistan, and Khorasan Razavi) of Iran. Of the 89 apiaries examined, 16 (17.97%), three (3.37%), and three (3.37%) were infected by DWV, ABPV, and CBPV, respectively. The study results for the other viruses (SBV, KBV, and BQCV) were negative. The present study evaluated the presence of the six most important honey bee viruses in bee colonies with suspected infections, and identified remarkable differences in the distribution patterns of the viruses in different geographic regions of Iran.

Genetic analysis of H9N2 avian influenza viruses circulated in broiler flocks: a case study in Iraq in 2014-2015.

H9N2 avian influenza viruses (AIVs) have been recorded in Eurasian for several years. Since 2004-2005, the disease has become endemic in Iraq, causing serious economic losses in the poultry industry. The hemagglutinin (HA) and neuraminidase (NA), two out of eight protein-coding genes, play an important role during the early stage of infection and hinder virus assembling. Little is known about the genetic information of the H9N2 viruses currently circulating in Iraq; thus, gene sequences of six AIVS of the H9N2 subtype have been detected and analyzed in the period of 2014-2015 from different outbreaks of broiler flocks in five provinces situated in the middle and southern parts of Iraq. Genetic comparison of the partial sequences of HA gene indicated that all Iraqi viruses are related to each other and could be divided into two subgroups. Viruses of the first and the second subgroups demonstrated a high similar identity with Pakistani and Iranian viruses, respectively. The nucleotide sequences of the NA protein of the all studied Iraqi viruses were very similar (95.2-100% identity), and shared high nucleotide sequence identity with Iranian, Pakistani, and Lebanese strains. All six recent viruses possessed histidine, alanine, and leucine at positions 183, 190, and 226, respectively, which are the key residues in receptor-binding sites. The Iraqi viruses were closely related to viruses of G1-like lineage isolated from poultry flocks of Iran and Pakistan, suggesting that possible epidemiological links could be derived from a common origin. Further investigations are required and should include the viral isolation and full-length molecular characterization of H9N2 AIVs in this area.

Molecular identification and phylogenetic analysis of chronic bee paralysis virus in Iran.

Chronic bee paralysis virus (CBPV) is an unclassified polymorphic single-stranded RNA virus. Among the viruses infecting honeybees, CBPV is known to induce significant losses in honeybee colonies. In this study, a total number of eighty-nine suspected apiaries from four regions of Iran (including Mazandaran, Khorasan Razavi, Hormozgan, and Kurdistan) were sampled and submitted for molecular identification. Three positive samples were detected by RT-PCR. All positive samples were confirmed by sequencing. The phylogenetic tree which displays the molecular relationship between the viruses of different Iranian geographic regions and references isolates was constructed. The Iranian isolates formed two distinct phylogenetic groups (Group 1 and Group 2). The IR-CPV-GMG-1, IR-CPV-GMG-2, IR-CPV-GMG-4, and IR-CPV-GMG-6 formed Group 1 and IR-CPV-GMG-3, IR-CPV-GMG-5, and IR-CPV-GMG-7 were in Group 2 as a distinct group. Iranian isolates in group 1 were similar to European and East Asian CBPVs. This research was the first phylogenetic analysis of CBPV in Iran. Further researches are needed to study the other aspects of this virus-like genetic characteristics and pathogenesis in Iran.

Genotyping of infectious bronchitis viruses from broiler farms in Iraq during 2014-2015.

Infectious bronchitis virus (IBV) is one of the most critical pathogens in the poultry industry, causing serious economic losses in all countries including Iraq. IBV has many genotypes that do not confer any cross-protection. This virus has been genotyped by sequence analysis of the S1 glycoprotein gene. A total of 100 tracheal and kidney tissue specimens from different commercial broiler flocks in the middle and south of Iraq were collected from September 2013 to September 2014. Thirty-two IBV-positive samples were selected from among the total and were further characterized by nested PCR. Phylogenetic analysis revealed that isolates belong to four groups (group I, variant 2 [IS/1494-like]; group II, 793/B-like; group III, QX-like; group IV, DY12-2-like). Sequence analysis revealed nucleotide sequence identities within groups I, II, and III of 99.68 %-100 %, 99.36 %-100 %, and 96.42 %-100 %, respectively. Group I (variant 2) was the dominant IBV genotype. One Chinese-like recombinant virus (DY12-2-like) that had not been reported in the Middle East was detected. In addition, the presence of QX on broiler chicken farms in the area studied was confirmed. This is the first comprehensive study on the genotyping of IBV in Iraq with useful information regarding the molecular epidemiology of IBV. The phylogenetic relationship of the strains with respect to different time sequences and geographical regions displayed complexity and diversity. Further studies are needed and should include the isolation and full-length molecular characterization of IBV in this region.

Prevalence of avian infectious bronchitis virus in broiler chicken farms in south of Iraq, 2014 - 2015.

Avian infectious bronchitis (IB), caused by a gammacoronavirus, is an OIE-listed (List B) disease and characterized by respiratory and renal involvements, causing high mortality, and economic loss in both layers and broilers. In comparison with other diagnostic methods, real-time polymerase chain reaction (RT-PCR) and conventional RT-PCR are potent, more sensitive and faster techniques for infectious bronchitis virus (IBV) detection. This research was conducted to detect IBV using specific primers of IB in three governorates (Basra, Thi-Qar and Muthana) in the south of Iraq. Tracheal specimens were collected from 46 IB suspected commercial broiler flocks. XCE2+ and XCE2- Primers, which amplify all IBV serotypes, were used. Primers MCE1+, BCE1+ and DCE1+ were used to amplify the specific nucleotide sequences of Massachusetts, 793/B and D274 genotypes, respectively. The results of real-time RT-PCR of this study showed that 34 (74.00%) out of 46 infected flocks were positive to IBV. The results of nested PCR showed that 50.00% and 5.89% of positive samples were belonged to genotypes 793/B and Massachusetts, respectively, and the remaining positive (44.11%) were unknown. The results indicate presence of Massachusetts and 793/B IBV strains in commercial broilers in southern Iraq.

Molecular characterization of infectious bronchitis viruses isolated from broiler chicken farms in Iran, 2014-2015.

Infectious bronchitis (IB) is a viral avian disease with economic importance in the world, including Iran. S1 gene sequencing has been used for molecular epidemiological studies and genotypic characterization of infectious bronchitis virus (IBV). A total of 118 IBV isolates were obtained from tissue samples from chickens with clinically suspected IB from Iranian broiler farms (eight provinces, 200 samples). The isolates were confirmed by real-time polymerase chain reaction (PCR) and characterized by sequencing the spike glycoprotein gene. The isolates formed six distinct phylogenetic groups (IS/1494/06 [Var2] like, 4/91-like, IS/720-like, QX-like, IR-1 and Mass-like) that were related to variants isolated in the region. The most frequently detected viruses were of the Var2-like (IS/1494/06-like) genotype, with an overall prevalence of 34 %. Twenty-one percent of the isolates formed a cluster together with the 4/91 IBV type, 10 % were of the QX genotype, and 8 % were of the IS/720 genotype. In addition, 4 % and 3 % of the isolates belonged to the Massachusetts and IR-1 genotype, respectively. For the first time, we have isolated and characterized IBV variants from broiler farms in different provinces of Iran. This study demonstrates a constant evolution of IBV in Iran, demonstrating the need for continuous monitoring and development of new vaccines based on indigenous viruses.

In vitro anti-foot-and-mouth disease virus activity of magnesium oxide nanoparticles.

Foot-and-mouth disease (FMD) is an extremely contagious viral disease of cloven-hoofed animals that can lead to huge economic losses in the livestock production. No antiviral therapies are available for treating FMD virus (FMDV) infections in animals. The antiviral effects of magnesium oxide nanoparticles (MgO NPs) on the FMDV were investigated in cell culture. The viability of the cells after MgO NP treatment was determined using the MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay. The direct effects of MgO NPs on the FMDV in extracellular (virucidal assay) and also different stages of virus replication (antiviral assay) were evaluated by plaque reduction assay. The results showed that MgO NPs were safe at concentrations up to 250 µg/ml in the Razi Bovine kidney cell line. The treatments with NPs indicated that the MgO NPs exerted in vitro virucidal and antiviral activities. Plaque reduction assay revealed that MgO NPs can inhibit FMDV by more than 90% at the early stages of infection such as attachment and penetration but not after penetration. The results of this study suggested that NPs might be applied locally as an antiviral agent in early stages of infection in susceptible animals.

Genotyping and determining the distribution of prevalent G and P types of group A bovine rotaviruses between 2010 and 2012 in Iran.

Determination and distribution of the G and P genotypes of group A bovine rotavirus was investigated on 386 fecal samples collected from calves with diarrhea using a semi-nested RT-PCR typing assay. Samples were collected from 11 provinces of Iran during 2010-2012. The provinces divided into 5 different groups based on geographical distance and climates. One hundred and nine samples (28.2%) were confirmed positive for rotavirus group A using ELISA. 75 positive samples were selected randomly and subjected to typing assay. G10 (50.6%) and P[11] (64%) were detected more than G6 (21.3%) and P[5] (9.3%). No any G8 and P[1] were observed. Of the 75 samples analyzed by RT-PCR in each geographical areas named as the south of Alborz mountain ranges area, the north-east area, the central area, the north-west area and the south-east area, number of samples with G10 genotype were 19, 9, 9, 0 and 1; G6 were 8, 0, 3, 5 and 0; P[11] were 25, 7, 11, 5 and 0 and finally P[5] were 5, 0, 2, 0 and 0 in each area, respectively. The most common VP7/VP4 combinations were G10P[11] (40%), G6P[11] (12%), G6P[5] (5.3%) and G10P[5] (2.6%). Phylogenetic analysis of one strain showed high identity with strain B223. Since the identification of G and P genotypes and their diversity is fundamental to development and use of effective vaccines, we determined the most prevalence G and P genotypes of bovine rotavirus group A (BRVA) in a broad area of Iran.

In Silico Analysis of HA2/Mx Chimera Peptide for Developing an Adjuvanted Vaccine to Induce Immune Responses Against Influenza Viruses.

PURPOSE: The direct transmission of avian influenza viruses to human and increasing drug resisted strains posing new threats for public health. Therefore, development of efficient vaccines is needed to generate protective and persistent immunity to the viruses. METHODS: Three motifs of Mx protein sequence in human, mouse and poultry located in interferon induced (GTP ase) domain were candidate as biologic adjuvant for enhancing the immune responses against influenza virus. Chimera proteins composed with the conserved HA2 subunit of influenza virus and the Mx motifs named HA2/Mx were modeled and evaluated by in silico analysis includes bioinformatics algorithms in order to explore biological characteristics of these peptides. RESULTS: Amongst the predicted models, HA2/Mx1 peptide showed the better results following protein structures prediction, antigenic epitopes determination and model quality evaluation. Comparative homology modeling was performed with Swiss Model and the model was validated using ProSA. Epitope predictions revealed the construct could induce both B and T cell epitopes that expect a high immune response. CONCLUSION: Taken together, these data indicate that the HA2/Mx1 chimera peptide can be potentiated for developing an adjuvant-fused influenza vaccine capable of stimulating effective immune response.

Molecular and clinical study on prevalence of feline herpesvirus type 1 and calicivirus in correlation with feline leukemia and immunodeficiency viruses.

Upper respiratory tract diseases (URTD) are common clinical problem in cats worldwide. Feline calicivirus (FCV) and feline herpesvirus type 1 (FHV-1) are the main primary pathogens. Feline immunodeficiency virus (FIV) and Feline leukemia virus (FeLV) are also among the most common infectious diseases of cats which suppress the immunity. Oropharyngeal and conjunctival swabs and blood samples were taken from 16 cats with clinical signs of URTD and 26 clinically healthy cats. PCR and RT-PCR were used to detect FHV/FIV or FCV/FeLV infections, respectively. Feline calicivirus was detected in all cats with URTD and 87.00% and 93.00% of them were positive for FIV and FeLV, respectively. Feline herpesvirus rate of infection was 43.00% in sick cats. In clinically normal cats, prevalence rates of FCV and FHV were about 50.00%, but FIV and FeLV rates (42.00% and 65.00% respectively) were higher compared to other studies. Stomatitis was observed in 50.00% of cats with URTD. The main causative agent of corneal ulcers is FHV-1, but in 50.00% of cats with corneal ulcers, FCV was detected alone. It seems new variants of Caliciviruses are the main causative agents to attack uncommon tissues like cornea, although retroviral infections may be in the background of these various signs. The high retroviral prevalence may be due to existence of large population of stray cats. This is the first molecular study of FeLV and FCV in Iran and seems that FCV and FHV prevalence rates in FIV or FeLV infected cats is more than other non-infected ones.

Survey on O157:H7 enterohemorrhagic Escherichia coli (EHEC) in cattle in Golestan province, Iran.

BACKGROUND AND OBJECTIVES: A diverse group of Escherichia coli are known as enterohemorrhagic Escherichia coli (EHEC) including O157:H7 and non-O157 EHEC. Enterohemorrhagic strains are related to sever clinical conditions in humans including hemorrhagic colitis and hemolytic uremic syndrome, and most of the recorded outbreaks occurred due to O157: H7 E. coli. The aim of the present study was to investigate the presence of O157:H7 E. coli among healthy cattle in Golestan province. MATERIALS AND METHODS: Fecal samples were collected from 180 clinically healthy cattle in Golestan province. After primary enrichment, samples were streaked on sorbitol MacConkey agar supplemented with cefixime and potassium tellurite (CT-SMAC). Non-sorbitol fermenting (NSF) Escherichia coli isolates were subjected to serotyping using commercial O157 antisera and rfb O157 gene PCR. Isolates were additionally tested for major virulence factors of EHEC including stx1, stx2, eae and ehly by multiplex-PCR. RESULTS: Eighteen NSF isolates were recovered from CT-SMAC confirmed as E. coli in biochemical tests. None of the obtained isolates belonged to O157 serogroup. Overall, two isolates harbored the tested virulence genes; one isolate possessed stx2 and ehly, and the other one carried stx2, eae and ehly. CONCLUSION: The results of this study indicated that cattle in Golestan province could be the reservoir for non-O157 EHEC.

Evaluation of random amplified polymorphic DNA analysis and antibiotic susceptibility application in discrimination of salmonella typhimurium isolates in Iran.

The purpose of this study was to determine the utility of RAPD-PCR and antibiotic susceptibility tests in differentiation of S. typhimurium isolates in Iran. Thirty isolates of S. typhimurium, selected based on animal source; place and time of the isolation and a reference strain of the bacterium were used in this study. Serotyping of the isolates was performed by reliable antisera and confirmed with a multiplex PCR. Genomic DNAs were extracted and subjected to an optimized RAPD-PCR, using two previously reported arbitrary primers (P1254 and 23L). Bacteria were also examined for resistance against 8 antibiotics, using a standard antibiotic susceptibility test. While the antibiotic susceptibility test resulted in the identification of 13 profiles of R-type among the bacterial isolates, application of primers P1254 and 23L in the RAPD-PCR could discriminate the isolates only in four and six profiles respectively. However, combination of the two methods could differentiate the 30 isolates in 20 different profiles. The results of this study indicate that the discriminatory power of RAPD-PCR for S. typhimurium is low but a combination of this method with antibiotic susceptibility test could be considered an easy and relatively reliable discriminatory approach in differentiation of S. typhimurium for epidemiologic purposes in Iran.