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Objective: The foodborne pathogen Salmonella enterica serovar Typhimurium causes self-limiting gastroenteritis in humans and is difficult to eliminate due to its ability to adhere to surfaces and form biofilms that exhibit high resistance to antimicrobial agents. To explore alternative strategies for biofilm treatment, it is essential to investigate novel agents that inhibit Salmonella biofilms., Method: In this study, we investigated the minimum biofilm inhibitory concentrations (MBICs) and minimum biofilm eradication concentrations (MBECs) of nafcillin and diosmin, both previously identified as Lon protease inhibitors, against biofilms formed by S. Typhimurium. Furthermore, we examined the expression of genes associated with the type II toxin-antitoxin system to enhance our understanding of the impact of these inhibitors., Results: The findings indicated a strong antibiofilm effect of nafcillin, with MBIC and MBEC values of 8 µg/mL and 32 µg/mL, respectively. These results were confirmed by field emission scanning electron microscopy (FE-SEM), which showed that biofilm formation was reduced in the presence of nafcillin. Additionally, it revealed morphological changes in the bacteria within the nafcillin-treated biofilms. Furthermore, gene expression analyses demonstrated a significant reduction in the expression of type II TA system genes following treatment with nafcillin and diosmin., Conclusion: This study highlights the effectiveness of nafcillin in disrupting the biofilms of S. Typhimurium. These results suggest promising avenues for the development of novel therapeutic strategies targeting biofilms associated with S. Typhimurium., Competing Interests: Declarations. Ethical approval: This study was approved by the Ethics Committee of Iran University of Medical Sciences by Ethics No. (IR.IUMS.FMD.REC.1402.262). Consent for publication: Not applicable. Competing interests: The authors declare no competing interests., (© 2024. The Author(s).)

Objective: Persister cells are a specific subset of bacteria capable of surviving exposure to lethal doses of antibiotics, leading to antibiotic therapy failures and infection relapses. This research explores the utilization of drug repositioning to target the Lon protease in Salmonella Typhimurium., Method: In this study, FDA-approved drugs sourced from the Drug Bank database were screened to identify existing pharmaceuticals with the potential to combat the Lon protease. The formation of persister cells in the presence of antibiotics, as well as the combination of antibiotics with potential Lon protease inhibitors, was examined. Furthermore, the expression of type II toxin-antitoxin system genes was analyzed to enhance our comprehension of the inhibitors' effects., Result: Molecular docking analysis revealed that Diosmin and Nafcillin exhibited strong binding affinity to the Lon protease. Molecular dynamics simulation trajectories analysis demonstrated that the interaction of these ligands with the enzyme did not induce instability; rather, the enzyme's structure remained stable. Combinations of ceftazidime and ciprofloxacin with either Nafcillin or Diosmin led to significant reductions in bacterial cell counts. Furthermore, the effectiveness of these combinations, when compared to antibiotics alone, highlighted the substantial impact of Nafcillin and Diosmin in reducing type II TA system gene expression., Conclusion: These findings suggest promising prospects for developing novel therapeutic approaches targeting persister cells to mitigate treatment failures in Salmonella infections., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Narimisa, Razavi, Khoshbayan, Gharaghani and Jazi.)

Legionella pneumophila can be transmitted to people, especially immunocompromised patients, via hospital water pipe systems and cause severe pneumonia. The aim of our study was to investigate the presence of major virulence factor genes, ability of biofilms formation, and correlation between presence of Legionella isolates and temperature, pH, and residual chlorine of water. Hundred water samples were collected from nine hospitals in Tehran, Iran. Temperature, pH, and residual chlorine were determined during sampling. Different virulence genes and the ability to form biofilms were subsequently analyzed among the L. pneumophila isolates. Results showed that 12 (12%) samples were positive in culture method and all of the isolates were positive as L. pneumophila species (mip). A correlation was found between Legionella culture positivity and temperature and pH of water, but there was no significant correlation between residual chlorine of water samples and the presence of Legionella. The isolation of Legionella rate in summer and spring was higher than winter and autumn. Twelve (100%) isolates were positive for mip genes, 9 (75%) for dot genes, 8 (66.66%) for hsp, 6 (50%) for lvh, and 4 (33.33%) for rtx. All of the isolates displayed strong ability for biofilm production every three days. Two of these isolates (16.6%) displayed weak ability to form biofilm on the first day of incubation. This study revealed that water sources in hospitals were colonized by virulent Legionella and should be continuously monitored to avoid elevated concentrations of Legionella with visible biofilm formation., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Background: Mycobacterium kansasii infection is one of the most common causes of non-tuberculosis mycobacterial (NTM) disease worldwide. However, accurate information on the global prevalence of this bacterium is lacking. Therefore, this study was conducted to investigate the prevalence of M. kansasii in clinical and environmental isolates., Methods: Databases, including PubMed, Scopus, and the Web of Science, were utilized to gather articles on the prevalence of M. kansasii in clinical and environmental isolates. The collected data were analyzed using Comprehensive Meta-Analysis software., Results: A total of 118 and 16 studies met the inclusion criteria and were used to analyze the prevalence of M. kansasii in clinical and environmental isolates, respectively. The prevalence of M. kansasii in NTM and environmental isolates were 9.4 and 5.8%, respectively. Subsequent analysis showed an increasing prevalence of M. kansasii over the years. Additionally, the results indicated a significant difference in the prevalence of this bacteria among different regions., Conclusion: The relatively high prevalence of M. kansasii among NTM isolates suggests the need for further implementation of infection control strategies. It is also important to establish appropriate diagnostic criteria and management guidelines for screening this microorganism in environmental samples in order to prevent its spread, given its high prevalence in environmental isolates., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Narimisa, Bostanghadiri, Goodarzi, Razavi and Jazi.)

Alzheimer's disease (AD), a neurological disorder, despite significant advances in medical science, has not yet been definitively cured, and the exact causes of the disease remain unclear. Due to the importance of AD in the clinic, large expenses are spent annually to deal with this neurological disorder, and neurologists warn of an increase in this disease in elderly in the near future. It has been believed that microbiota dysbiosis leads to Alzheimer's as a multi-step disease. In this regard, the presence of footprints of perturbations in the oral microbiome and the predominance of pathogenic bacteria and their effect on the nervous system, especially AD, is a very interesting topic that has been considered by researchers in the last decade. Some studies have looked at the mechanisms by which oral microbiota cause AD. However, many aspects of this interaction are still unclear as to how oral microbiota composition can contribute to this disease. Understanding this interaction requires extensive collaboration by interdisciplinary researchers to explore all aspects of the issue. In order to reveal the link between the composition of the oral microbiota and this disease, researchers from various domains have sought to explain the mechanisms of shift in oral microbiota in AD in this review., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Objectives: Chronic infections and treatment failure are concerning issues in patients with Pseudomonas aeruginosa infections. Persister cell formation in biofilm is considered a key reason for antibiotic resistance and treatment failure. In this study, expression of type II toxin/antitoxin (TA) system genes (relBE, Xre-COG5654, vapBC and Xre-GNAT) in persister cells of biofilm was evaluated in the presence of the antibiotics ciprofloxacin and colistin during exponential and stationary phases., Methods: The impact of antibiotics on biofilm persister cell formation during exponential and stationary phases of P. aeruginosa strains was examined by colony count at different time intervals in the presence of 5-fold minimum inhibitory concentration (MIC) of ciprofloxacin and colistin. Furthermore, expression of relBE, Xre-COG5654, vapBC and Xre-GNAT genes in P. aeruginosa strains undergoing antibiotic treatment for 3.5 h during exponential and stationary phases was examined by RT-qPCR., Results: Formation of persister cells was observed in biofilms formed by P. aeruginosa strains in the presence of 5 × MIC of ciprofloxacin and colistin compared with the control group after 3.5 h of incubation both during exponential and stationary phases. The number of biofilm persister cells was higher in stationary phase than in exponential phase. According to the findings of RT-qPCR, ciprofloxacin and colistin may induce persister cell formation by enhancing the expression of type II TA systems during stationary and exponential phases., Conclusion: The result of this study indicate that ciprofloxacin and colistin have the potential to increase persister cells formation in biofilms by influencing the expression of type II TA systems., (Copyright © 2021 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Listeria monocytogenes is responsible for causing listeriosis, a type of food poisoning with high mortality. This bacterium is mainly transmitted to humans through the consumption of contaminated foods. Detection of L. monocytogenes through molecular methods is crucial for food safety and clinical diagnosis. Present techniques are characterized by low discrimination power and high cost, as well as being time-consuming and taking several days to give the final result. In our study, MLVA-HRM (Multiple-Locus Variable-number tandem repeats Analysis ‒ High-Resolution Melting) was investigated as an alternative method for a fast and precise method for the genotyping of L. monocytogenes isolates. Forty-eight isolates of L. monocytogenes obtained from the microbial bank of Department of Microbiology, Iran University of Medical Sciences, were typed by MLVA-HRM analysis using five Variable Numbers of Tandem Repeat (VNTR) loci. A total of 43 different types were obtained. This research demonstrated the usefulness of the MLVA-HRMA method and its ability to discriminate L. monocytogenes isolates. Since this method is easier and more efficient than existing methods, it can be widely used in food processing plants and diagnostic laboratories as a fast and accurate method., Competing Interests: Conflicts of interest The authors declare no conflicts of interest., (Copyright © 2022. Published by Elsevier España, S.L.U.)

Background: Tuberculosis (TB) is still one of the most important causes of death worldwide. The lack of timely attention on TB diagnosis and treatment during the coronavirus disease 2019 (COVID-19) pandemic is a potential threat to health issues and may have severe consequences for patients and health systems. There is not much information on the management of TB during this period. Here, we reviewed the current literature to evaluate the rate of Mycobacterium tuberculosis and severe acute respiratory syndrome coronavirus 2 coinfections and interactions between these infectious agents., Methods: Several databases, including Web of Science, Scopus, and MEDLINE (via PubMed), were searched for original articles addressing TB and COVID-19 diseases published from December 2019 to April 2021., Results: Of 3,879 articles, 57 articles were included in this study, and among 106,033 patients affected by COVID-19, 891 also had TB. Overall, investigators found a consistent increase in C-reactive protein, D-dimer (especially in patients with severe clinical manifestation), erythrocyte sedimentation rate, lactate dehydrogenase, alanine aminotransferase, and a reduction of lymphocytes. The respiratory symptoms of TB/COVID-19 patients were similar to those of TB patients, but the risk of developing pulmonary TB increased in COVID-19 patients. Also, the mortality rate in TB/COVID-19 patients was higher than that in patients affected only by COVID-19 or TB., Conclusion: Some reports indicated worsening respiratory symptoms and even activation of latent TB after COVID-19 or vice versa. It seems that both active and previously treated TB constituted a risk factor for COVID-19 in terms of severity and mortality, regardless of other underlying diseases and patient status. Health systems should not neglect TB during this era of the ongoing COVID-19 pandemic by setting up appropriate diagnostic and clinical management algorithms., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Bostanghadiri, Jazi, Razavi, Fattorini and Darban-Sarokhalil.)

Aims and Background: Lactobacillus spp. are an important element in breast milk. This component has a beneficial effect on the composition of the intestinal microflora and the intestinal immune system. The aim of this study was to isolate and identify Lactobacillus strains in breast milk and evaluate some of their probiotic properties, such as presence of bacteriocin genes, adhesion to HT-29 cell line, competition with enteropathogens in cell culture, and effect on serum level of lipids and digestive enzymes, and mice model of inflammatory bowel disease (IBD)., Materials and Methods: A total of 323 lactic acid bacteria (LAB) were isolated from breast milk samples of healthy mothers with the age ranges from 21 to 45 years old. These isolates were subjected to phenotypic and molecular experiments. The frequency of bacteriocin genes was determined by polymerase chain reaction (PCR). Adhesion of Lactobacillus isolates to HT-29 cells was measured based on the number of attached bacterial cells in 20 fields of the light microscopy. Competition test was done by colony count and real-time PCR procedures. Five strongly adhesive Lactobacillus strains were selected and administered orally to the treatment groups. After 8 days, the serum level of digestive enzymes and improvement in induced IBD, and after 14 days, the serum level of lipids (triglycerides, total cholesterol, HDL, and LDL) in treated mice were surveyed compared to the control groups., Results: Based on the phenotypic and molecular experiments, L. casei, L. plantarum, L. rhamnosus, and L. acidophilus strains were isolated and identified in the breast milk samples. The highest frequency of bacteriocin genes belonged to Plantaricin B (100%), followed by Plantaricin D (84.7%), Plantaricin G (84.7%), and Plantaricin EF (54.3%). Also, 71.8% of the isolates were strongly adhesive, 21.8% were non-adhesive, and 6.4% were adhesive. Lactobacillus strains had a significant effect on the displacement of enteropathogens. The in vitro cholesterol-removing ability of L. casei (L1), L. casei (L2), L. casei (L3), L. plantarum (L4), and L. rhamnosus (L5) was 3.5, 31.5, 21.3, 18.7, and 27.3%, respectively. The serum level of total cholesterol in the L. plantarum (L4) group as well as LDL in the L. casei (L3) (p = .0108) and L. rhamnosus (L5) (p = .0206) groups decreased significantly compared to the control group. The serum level of lipase increased in all the treatment groups compared to the control group, which was significant in the L. plantarum (L4) group (p = .0390). Disease activity index (DAI) scores were improved significantly in L. casei (L3) group compared to the IBD control group (p < .0001)., Conclusion: It could be concluded that lactobacilli strains isolated from the breast milk samples had good probiotic properties, such as presence of bacteriocin genes, attaching to enterocyte-like HT-29 cells, competing with intestinal pathogens, lowering cholesterol, and improving IBD. Thus, after further studies, they could be considered as probiotic strains., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Acinetobacter baumannii is one of the most important etiologies of nosocomial infections in recent years mainly because of increasing in frequency of multidrug and pan-resistant pathogens. Meningitis caused by this organism is a dilemma; because polymyxins are the only effective antibiotics against pan-resistant serotypes, but have poor penetration via blood brain barrier; however, it has still remained uncertain whether the intravenous therapy with these agents is an effective treatment with the sufficient concentration of the drug in the cerebrospinal fluid. Herein, we report a neonate who suffered from pan-resistant A. baumannii nosocomial meningitis successfully treated with intravenous colistin combined with meropenem and rifampin. It seems that intravenous colistin at least in combination with rifampin and meropenem might be considered as an option to try in patients in whom daily intrathecal injection or insertion of intraventricular device is not possible., Competing Interests: No conflicts of interest., (Copyright © 2021 by The Korean Society of Infectious Diseases, Korean Society for Antimicrobial Therapy, and The Korean Society for AIDS.)

Persisters are phenotypic variants of the bacterial population that survive against lethal doses of bactericidal antibiotics.These phenotypes are created in numerous bacterial species, including those of clinical significance, such as Salmonella Typhimurium. Since persister cells are associated with the failure of antibiotic treatment and infection recurrence, it is crucial to identify the mechanisms that influence the formation of these cells. The aim of this study is to investigate the persister cell formation and expression analysis as well as to predict the 3D structure of the genes involved in the production of persister cells. The presence of persisters in S. Typhimurium was determined by time dependent killing of different types of bactericidal antibiotics and expression of genes associated with persister cell formation which was assessed five hours after the addition of antibiotics by the qRT-PCR. Indeed, the 3D structural model of the proteins studied was predicted by performing several computational methods of retrieved primary protein sequences. The results of the study showed that the S. Typhimurium produced high levels of persister cells in the exposure of bactericidal antibiotics. Furthermore, qRT-PCR resulted in the fact that the expression of related genes was different depending on the type of antibiotic. Overall, this study provides information on the creation of persister cells and the role of different genes in the formation of these cells and structure of proteins involved in the production of persister cells in S. Typhimurium.

Background: Toxin-antitoxin systems (TAs) are two-component elements, which are extensive in the bacterial genome and have a regulatory role in many cellular activities including, growth arrest, survival, biofilm formation, and bacterial persistence., Objective: TAs have not well studied in Brucella spp., Methods: We evaluated the presence of different toxin-antitoxin systems, including relE- rhhlike, Fic- Phd, Cog- Rhh, and cogT- cogAT in 40 clinical Brucella melitensis isolates using PCRbased sequencing assay., Results: Our results showed the high presence of relE-rhh-like, Fic-Phd, Cog-rhh, and cogTcogAT s TAs genes in B. melitensis isolates that were 96.25%, 92.5%, 96.25%, and 95%, respectively., Conclusion: A high presence of TAs genes in clinical B. melitensis isolates revealed that the TA system could be an antibacterial target in B. melitensis but more investigation is necessitated to elucidate the exact roles of these genes., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Background: Brucellosis is considered a main health concern in humans and animals. Neither familiar molecular methods nor the classical biotyping techniques are acceptable for subtyping Brucella spp. Loci containing variable number tandem repeats (VNTRs) have recently demonstrated their practicality in typing isolates from human and animal origin despite the excessive genetic homogeneity in the genus Brucella., Methods: The genotypic characteristics of sixty-six Brucella melitensis and thirty-four Brucella abortus isolates from veterinary samples and human brucellosis cases in Iran during 2014 - 2018. They were analyzed using multiple-locus variable-number tandem-repeat analysis (MLVA) which consisted of sixteen primer pairs and designed and classified as belonging to one of the three panels: panel 1 (MLVA-8: eight loci including Bruce06, Bruce08, Bruce11, Bruce12, Bruce42, Bruce43, Bruce45, and Bruce55), panel 2A (three loci including Bruce18, Bruce19, and Bruce21), and panel 2B (five loci including Bruce04, Bruce07, Bruce09, Bruce16, and Bruce30); MLVA-11 (panels 1 and 2A), and MLVA-16 (panels 1, 2A, and 2B) using BioNumerics software (Version 7.6)., Results: Using panel 1, 2A, and 2B (MLVA-16), 59 genotypes with a genetic similarity coefficient ranging from 91 to 100% were obtained from the 100 Brucella spp. isolates. For all isolates, only genotype 36 and genotype 26 were obtained using panels 1 and 2A, respectively. The B. abortus isolates showed variations at 9 different genotypes, while B. melitensis isolates have been dispersed in 50 different genotypes. Bruce16 and Bruce4 showed the highest discriminatory power., Conclusions: The MLVA-16 assay appeared to be a useful and important molecular genotyping tool that is capable of proving epidemiological linkages in outbreak and trace-back investigations and is helpful in improving the effectiveness of brucellosis control programs.

Objectives: Sub-inhibitory concentrations (sub-MICs) of antibiotics reflect the conditions that bacteria encounter in tissues and the natural environment. Sub-MICs of antibiotics can induce stress and alter the expression of different bacterial genes. Bacteria react to stress conditions using different mechanisms, one of which is the toxin-antitoxin (TA) system. This study investigated the expression of the TA system genes under oxidative and antibiotic stresses in Klebsiella pneumoniae (K. pneumoniae)., Methods: To determine the effects of sub-MICs of gentamicin, nalidixic acid, ceftazidime, and certain concentrations of H 2 O 2 on bacterial survival and growth, colony forming units were quantitated and turbidity was assessed following the treatment of K. pneumoniae with ½ MICs of antibiotics and 5 mM H 2 O 2 at different time intervals. The expression of TA system genes in K. pneumoniae was evaluated 1 h after treatment using the quantitative real-time PCR (qRT-PCR) method., Results: The results revealed reduced K. pneumoniae growth in the presence of sub-MICs of antibiotics and 5 mM H 2 O 2 compared to the control. Furthermore, according to the results of the qRT-PCR assay, only the presence of gentamicin could increase the expression of TA system genes., Conclusion: Although the exact role of the TA systems in response to stress is still unclear, this study provided information on the effect of the type II TA systems under oxidative and antibiotic stress conditions., (Copyright © 2019 International Society for Antimicrobial Chemotherapy. Published by Elsevier Ltd. All rights reserved.)

Brucellosis is one of the most common zoonotic diseases of animal and human beings. This study aimed to differentiate the Brucella spp. and determines the patterns of biovars by using repetitive element palindromic (REP)-PCR and PCR restriction fragment length polymorphism (RFLP) methods. A total of 100 blood specimens suspected of harbouring brucellosis were collected. Conventional culture methods and multiplex PCR were used for the detection of Brucella genus and species; and REP-PCR was used for Brucella spp. differentiation and polymorphisms sequence analysis. In addition, to identify the biovar patterns of REP-PCR, PCR-RFLP was used. Eighty-three samples were identified as harbouring Brucella spp. by the implementation of multiplex PCR, 72 of which were detected as Brucella melitensis and 11 as B. abortus. Also, through analysing the results of PCR-RFLP, it was found that of 72 B. melitensis samples, 69 were B. melitensis biovar 1 and three species were from other biovars. In addition, the obtained patterns for all of the B. abortus samples were from biovars 3, 5, 6 and 9. This study also optimized a test for the detection of Brucella biovar with the REP-PCR method such that Brucella spp. and biovars could be separated in the shortest possible time., (© 2019 The Author(s).)

Background: Mycobacterium avium-intracellulare complex (MAC) is one of the leading causes of death among people living with human immunodeficiency virus (HIV). The current study was aimed to determine the frequency of MAC infection in patients infected with HIV., Methods: Embase, PubMed, and Web of Science were searched for relevant studies. All statistical analyses were performed by STATA version 14., Results: From 6,627 retrieved articles, 23 were included in the final analysis. A total of 18,463 patients with HIV were included in the analysis. The frequency of MAC infection in patients with HIV was found to be 10.6% (95% confidence interval, 6.9-14.2)., Conclusion: The relatively large fractions of HIV-infected patients were coinfected with MAC, which may poses significant public health problems. Continued progress in the development of rapid diagnostic methods and preventive therapy for MAC should lead to further improvements in survival and quality of life in patients with HIV., (© 2018 Wiley Periodicals, Inc.)

Brucellosis is still one of the most challenging issues for health and the economy in many developing countries such as Iran. Considering the high prevalence of brucellosis, the aim of the current study was to systematically review published data about the annual incidence rate of this infection from different parts of Iran and provide an overall relative frequency (RF) for Iran using meta-analysis. We searched several databases including PubMed, ISI Web of Science, Scopus, google scholar, IranMedex and Iranian Scientific Information Database (SID) by using the following keywords: "Brucella", "Brucellosis", "Malta fever", "Mediterranean fever", "undulant fever", "zoonosis" and "Iran" in Title/Abstract/Keywords fields. Articles/Abstracts, which used clinical specimens and reported the incidence of brucellosis, were included in this review. Quality of studies was assessed by STROB and PRISMA forms. All statistical analyses were performed using STATA 11.0 (STATA Corp, College Station, TX) and P-values under 0.05 were considered statistically significant. Out of the 8326 results, we found 34 articles suitable, according to inclusion and exlusion criteria, for inclusion in this systematic review and meta-analysis. The pooled incidence of brucellosis was estimated 0.001% (95% confidence interval (CI) = 0.0005-0.0015%) annually. Relative frequency of brucellosis in different studies varied from 7.0/100000 to 276.41/100000 in Qom and Kermanshah provinces, respectively. This systematic-review and meta-analysis study showed that the highest incidences of brucellosis are occurred in west and northwest regions of Iran. Totally, the incidence of the disease in Iran is in the high range., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Brucella is zoonotic pathogen that induces abortion and sterility in domestic mammals and chronic infections in humans called Malta fever. It is a facultative intracellular potential pathogen with high infectivity. The virulence of Brucella is dependent upon its potential virulence factors such as enzymes and cell envelope associated virulence genes. The aim of this study was to investigate the Brucella virulence factors among strains isolated from humans and animals in different parts of Iran. Seventy eight strains of Brucella species isolated from suspected human and animal cases from several provinces of Iran during 2015-2016 and identified by phenotypic and molecular methods. The multiplex-PCR (M-PCR) assay was performed in order to detect the ure, wbkA, omp19, mviN, manA and perA genes by using gene specific primers. Out of 78 isolates of Brucella spp., 57 (73%) and 21 (27%) isolates were detected as B. melitensis and B. abortus, respectively, by molecular method. The relative frequency of virulence genes ure, wbkA, omp19, mviN, manA and perA were 74.4%, 89.7%, 93.6%, 94.9%, 100% and 92.3%, respectively. Our results indicate that the most of Brucella strains isolated from this region possess high percent of virulence factor genes (ure, wbkA, omp19, mviN, manA and perA) in their genome. So, each step of infection can be mediated by a number of virulence factors and each strain may have a unique combination of these factors that affected the rate of bacterial pathogenesis., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Molecular prevalence of nine putative virulence factors in two more prevalent Brucella species in Iranian patients and livestock was investigated. During five years (2010-2015), 120 human and animal specimens were collected from three geographical areas of Iran. All samples were cultured in blood culture media and subcultured into Brucella agar medium. Nine primer pairs were designed for detection of VirB2, VirB5, VceC, BtpA, BtpB, PrpA, BetB, BPE275 and BSPB virulence factors using PCR and sequence analysis. Totally, 68 Brucella isolates including 60 B. melitensis and 8 B. abortus were isolated from the human and animal specimens examined. Approximately, all B. melitensis and B. abortus strains were positive (100%) regarding btpA, btpB, virB5, vceC, bpe275, bspB, and virB2 genes except for prpA and betB that were detected in 86% and 97% of the strains, respectively. Significant relationships were found between the presence of prpA and human B. melitensis isolates (P = 0.04), and also between the presence of betB and human isolates of B. abortus (P = 0.03). In conclusion, our results revealed that Iranian Brucella strains, regardless of human or animal sources, are extremely virulent due to high prevalence of virulence attributes in almost all strains studied., (Copyright © 2017 Elsevier Ltd. All rights reserved.)