Molecular identification of Brucella species and biovars associated with animal and human infection in Iran

Molecular epidemiology of brucellosis in Asia: insights from genotyping analyses

Brucellosis infects humans and animals worldwide but is particularly prevalent in Asia. In many Asian countries, molecular diagnostic tools for accurate molecular diagnostics and molecular epidemiology are lacking. Nonetheless, some countries have conducted in-depth molecular epidemiological studies. The objective of this study was to reveal the genetic relationships, geographic origins, and distributions of Brucella strains across Asia for two primary species, B. abortus and B. melitensis. For this, we systematically searched genotyping data from published studies on the molecular epidemiology of Brucella species for both humans and livestock in Asia. We used data from multilocus sequence typing (MLST), multiple-locus variable-number tandem repeat analysis (MLVA), and whole genome sequencing analysis of Brucella strains. We also analyzed the MLVA genotypes of 129 B. abortus isolates and 242 B. melitensis isolates with known origins in Asia from an online MLVA database using MLVA-11 data in minimum spanning trees and MLVA-16 data in neighbor-joining trees. We found that the B. melitensis East Mediterranean lineage is predominant across the continent, with only a small number of samples from the Africa and Americas lineages, and none from the West Mediterranean lineage. The "abortus C" genotype was the most common group of B. abortus in Asia, with limited genetic variation for this species. Several studies also reported that Near Eastern countries frequently encounter human brucellosis cases of B. abortus from genotypes 42 and 43. Our study highlights the inconsistent collection of genetic data for Brucella species across Asia and a need for more extensive sampling in most countries. Finally, a consistent nomenclature is necessary to define various groupings of strains within a lineage (i.e., clade) so uniform terminology should denote particular genetic groups that are understood by all researchers.

Equine brucellosis in Iran: serological, bacteriological and molecular analysis

Equine brucellosis significantly impacts the health and functionality of horses, leading to complications such as bursitis infection, septic tenosynovitis, septic arthritis, and non-specific lameness resulting from joint infections. In the present study, we used the Rose Bengal plate agglutination test (RBPT), serum agglutination test (SAT), and the 2-mercaptoethanol (2-ME) assays to find equine brucellosis. From June 2018 to September 2022, 876 blood samples were randomly taken from apparently healthy racing horses in certain parts of Iran, such as Kerman, Isfahan, Tehran, Qom, and Kurdistan. DNA extraction was carried out directly on all 63 serum samples identified as seropositive through RBPT. An additional 30 seronegative serum samples were also randomly chosen for study. Bacterial culture was also done on milk, blood, and vaginal swabs taken from seropositive horses.The bacteria that were found in the samples were then put through Bruce-ladder PCR. Our results indicated that 63 (7.1%), 21 (2.3%), and 2 (0.2%) of horses were seropositive using RBPT, SAT, and 2-ME, respectively. Also, none of the 30 DNA-extracted serum samples from seronegative horses tested positive for Brucella DNA, while 44.5% (28/63) of the DNA samples from seropositive horses yielded positive results for Brucella DNA. Out of the seropositive samples, 26 had DNA from Brucella abortus and 2 had DNA from Brucella melitensis. Also, B. melitensis biovar 1 was found in two milk samples from mares in the provinces of Kerman and Isfahan. It was identified using classical biotyping, and molecular assays. It was seen that some of healthy racing horses in some parts of Iran had antibodies against Brucella. The bacteriology and PCR methodologies provide a more comprehensive and reliable means of identifying Brucella spp. infections in horse, especially when the RBPT test came back positive. This underscores the imperative for employing molecular, bacterial, and serological methods in the diagnosis and monitoring of this zoonotic infection. Additionally, this finding suggests that Brucella is being transmitted to equine hosts as a result of its presence in ruminants. The mechanism of transmission may involve interactions between infected ruminants and susceptible equines. This discovery is significant as it underscores the potential cross-species transmission of Brucella and highlights the importance of understanding and managing the spread of the pathogen in both ruminant and equine populations.

Brucellosis: Unveiling the complexities of a pervasive zoonotic disease and its global impacts

One zoonotic infectious animal disease is brucellosis. The bacteria that cause brucellosis belong to the genus Brucella. Numerous animal and human species are affected by brucellosis, with an estimated 500,000 human cases recorded annually worldwide. The occurrence of new areas of infection and the resurgence of infection in already infected areas indicate how dynamically brucellosis is distributed throughout different geographic regions. Bacteria originate from the blood and are found in the reticuloendothelial system, the liver, the spleen, and numerous other locations, including the joints, kidneys, heart, and genital tract. Diagnosis of this disease can be done by bacterial isolation, molecular tests, modified acid-fast stain, rose bengal test (RBT), milk ring test, complement fixation test, enzyme-linked immunosorbent assay, and serum agglutination test. The primary sign of a Brucella abortus infection is infertility, which can result in abortion and the birth of a frail fetus that may go on to infect other animals. In humans, the main symptoms are acute febrile illness, with or without localization signs, and chronic infection. Female cattle have a greater risk of contracting Brucella disease. Human populations at high risk of contracting brucellosis include those who care for cattle, veterinarians, slaughterhouse employees, and butchers. Antibiotic treatment of brucellosis is often unsuccessful due to the intracellular survival of Brucella and its adaptability in macrophages. A "one health" strategy is necessary to control illnesses like brucellosis.

Characterization of Brucella spp. circulating in industrial dairy cattle farms in Iran: a field study 2016 - 2023

Bovine brucellosis, an infectious disease transmitted by Brucella melitensis and Brucella abortus, presents a significant zoonotic risk for agricultural economics and animal health. The primary objective of this study was to present a comprehensive understanding of the prevalence and features of Brucella strains within the industrial dairy farming sector in Iran. Rose Bengal plate test, standard agglutination test, and indirect enzyme linked immunosorbent assay tests were used to confirm all seropositive animals. A total number of 1,311 bovine samples from seropositive animals including were collected from 224 farms in 21 provinces of different regions of Iran and examined. The discovered Brucella isolates were phenotyped and molecularly characterized. The isolates were all B. abortus or B. melitensis. Bacteria analysis revealed that 70.53% of seropositive farms were tested positive for Brucella strains, predominantly B. melitensis biovar 1 (43.42%) and B. abortus biovar 3 (27.11%). Geographical distribution revealed that B. melitensis biovar 1 was the most common in dairy cow farms (16 provinces), followed by B. abortus biovar 3 (six provinces). Also, the prevalence of B. melitensis biovar 2, B. melitensis biovar 3, B. abortus biovar 1, B. abortus biovar 2 and RB51 vaccine were restricted to certain provinces. AMOS (abortus melitensis ovis suis)-polymerase chain reaction and Bruce-ladder PCR confirmed species identification. These results highlighted the complexity of bovine brucellosis in Iran and illustrated that B. melitensis was spread from small ruminants to cattle. This study provided important epidemiological insights for targeting future brucellosis control programs in the Iranian dairy farms.

Serological, cultural, and molecular analysis of Brucella from Buffalo milk in various regions of Iran

Brucellosis is a significant infection that causes abortion, decreased milk production, and sterility in livestock, which greatly affects the industry. This study aimed to determine the prevalence of Brucella in buffalo milk samples across various regions of Iran, utilizing serological, molecular, and cultural analyses. A total of 1860 buffalo milk samples were collected from industrial, semi-industrial, and traditional buffalo farms in four major buffalo breeding provinces. The milk ring test agglutination test (MRT) was initially conducted on all milk samples, followed by culture and molecular testing for positive and negative samples in MRT. The study revealed positive results for the presence of Brucella DNA in various provinces of Iran. The MRT had a relatively low sensitivity, with results ranging from 0 to 0.7% in different provinces. However, the AMOS PCR method showed a significantly higher presence of Brucella DNA, ranging from 13 to 46% in these provinces. The highest abundance of Brucella bacterial DNA was found in Ardabil province, while the lowest was in West Azerbaijan province. Brucella abortus was the most commonly detected bacteria, followed by Brucella melitensis. Interestingly, the B. abortus vaccine strain RB51 was detected in 26.3% of positive samples of B. abortus. The culture assay of milk samples further confirmed the presence of B. melitensis biovar 1 in one sample from Khuzestan province. Overall, the study emphasizes that the AMOS PCR method is the most sensitive in detecting Brucella-exposed milk, while the sensitivity of milk sample culture and MRT is relatively lower.

Genetic diversity of Brucella melitensis isolates from sheep and goat milk in Iran

The genetic diversity of Brucella strains has not been fully understood. To investigate this, the genetic characteristics of 64 isolates of Brucella melitensis from sheep and goats' milk were studied using random fragment length polymorphism (RFLP) and multiple locus variable-number tandem repeat analysis (MLVA-16) methods developed in Orsay, France (MLVA-16Orsay). The RFLP analysis revealed that all 64 isolates were of biovar one. The MLVA-typing showed that one sample was simultaneously infected with two strains of B. melitensis and the genotype of 65 isolate was analyzed. Four genotypes (47, 42, 43, and 63) were identified using MLVA-8 (panel 1), whereas six genotypes (138, 125, 116, 108, and two unknown genotypes) were identified using MLVA11 (panels 1 and 2A). From the review of MLVA-16 (panels 1, 2A, and 2B), panel 2B showed a very high discriminatory power. Two loci of Bruc04 and Bruc30 from this panel had diversity index values higher than 0.71 and the average diversity index was 0.619. So MLVA-16Orsay 34 showed the genotype indicating a low genetic homogeneity among the isolates. The findings of MLVA genotyping of the isolates suggest that strains of B. melitensis isolated from the milk of small ruminants in Iran are most closely related to the isolates from neighboring countries of the Eastern Mediterranean group. To the best of our knowledge, this is the first study to indicate the potential use of MLVA genotyping for simultaneous detection of specimen contamination using two different B. melitensis biovars.

Investigation of the Proportion of Brucella abortus and Brucella melitensis in Sheep and Goat Milk

Despite the implementation of brucellosis eradication programs in Iran, this disease is still endemic and highly prevalent among ruminants in this country. The infection of small ruminants with Brucella abortus may play a significant role in the continuation of brucellosis among the herds of ruminants. This study investigated the proportion of B. abortus and Brucella melitensis in 150 samples of sheep and goat's raw milk which were obtained from Lorestan and Hamadan provinces in the western part of Iran using the PCR method. The results revealed that among the Brucella spp. positive samples, 26.5% and 73.4% of the samples were infected with B. abortus and B. melitensis, respectively. The incidence rates of B. abortus among the sheep and goats samples were 6.8% and 12.5%, respectively. There was a significant difference between goats and sheep regarding the proportion of B. abortus. Three samples (2%) (2 goats and one sheep) were simultaneously infected with both B. melitensis and B. abortus. This article renews our knowledge about the causative agent of brucellosis in small ruminants and shows that B. abortus has a relatively high prevalence among those animals in the western regions of Iran, and its role as one of the main factors of abortion among small ruminants should not be ignored. The information provided in the present study is important for the surveillance program, as eradication programs and strategies to prevent the spread of B. abortus among small ruminants that have not been vaccinated against this microorganism may be adapted accordingly.

Molecular Investigation of Brucella Species Belongs to Sheep and Goats in Seropositive Samples from an Endemic Area of Hamedan Province; Famenin Brucellosis Cohort Study

Brucellosis is a zoonotic infectious disease in western regions of Iran, especially in Hamedan province. Following the Famenin brucellosis cohort study, the main aim of the current study was the molecular detection of Brucella species (spp.) in sheep and goats from Famenin, Hamedan, Iran. A total of 23 Brucella-seropositive samples (sheep=21 and goats=2), which had been screened from 1,660 animals in the Famenin cohort study, were used to detect Brucella-DNA using the BCSP31 target gene and IS711 locus. In total, 20 of 23 samples were positive for Brucella infection by using specific primers. Additionally, Brucella melitensis (B. melitensis) and Brucella abortus (B. abortus) were confirmed in 90% (n=18) and 10% (n=2) of positive samples, respectively. There was no sample with the co-infection of B. abortus and B. melitensis. In this study, B. abortus was isolated from one of the goat samples. This is the first report on Brucella spp. in animals in the region. It was found that B. melitensis is the dominant spp. responsible for brucellosis in animals from Famenin. Molecular techniques are reliable tools to detect Brucella infection, especially in cases without serology findings and conclusive results.

The Control Program of Brucellosis by the Iranian Veterinary Organization in Industrial Dairy Cattle Farms

Brucellosis is a zoonotic infection in livestock that induces a major public health concern in developing countries, including Iran. Despite the efforts of the Iranian veterinary organization (IVO) to control brucellosis, it is still prevalent in domestic animals. In this regard, the present study aimed to evaluate the efficiency of the control strategy used by the IVO in infected herds on serological, cultural, and molecular methods. For this purpose, blood specimens were sampled from a total of 8750 vaccinated dairy cattle in two Brucella-infected farms. These farms were recognized as positive for Brucella by a screening program. Sera were evaluated by the Rose Bengal Plate Test and Wright test analysis. Positive dairy cattle were slaughtered under IVO supervision. The remaining cattle were evaluated every 3 weeks and positive animals were slaughtered. This procedure continued until the remaining animals revealed three successive negative responses in serological tests. Several lymph nodes and milk samples were collected from 164 seropositive cattle and subjected to bacterial isolation and confirmation by Bruceladder-polymerase chain reaction. Brucella melitensis biovar 1 and RB51 vaccine strains were recovered from milk and lymph node samples, respectively. Shedding of B. melitensis in the milk of vaccinated cows is a serious problem resulting in the further spread of brucellosis. The policy of "test and slaughter" performed on infected dairy cattle farms showed their usefulness for the control of brucellosis outbreaks. For the uncontrolled spread of brucellosis in Iran, effective control of bovine brucellosis required several serological surveillances to identify infected herds, eradication of the reservoirs, and vaccination of young heifers with RB51.

One Health: a holistic approach for food safety in livestock

The food safety of livestock is a critical issue between animals and humans due to their complex interactions. Pathogens have the potential to spread at every stage of the animal food handling process, including breeding, processing, packaging, storage, transportation, marketing and consumption. In addition, application of the antibiotic usage in domestic animals is a controversial issue because, while they can combat food-borne zoonotic pathogens and promote animal growth and productivity, they can also lead to the transmission of antibiotic-resistant microorganisms and antibiotic-resistant genes across species and habitats. Coevolution of microbiomes may occur in humans and animals as well which may alter the structure of the human microbiome through animal food consumption. One Health is a holistic approach to systematically understand the complex relationships among humans, animals and environments which may provide effective countermeasures to solve food safety problems aforementioned. This paper depicts the main pathogen spectrum of livestock and animal products, summarizes the flow of antibiotic-resistant bacteria and genes between humans and livestock along the food-chain production, and the correlation of their microbiome is reviewed as well to advocate for deeper interdisciplinary communication and collaboration among researchers in medicine, epidemiology, veterinary medicine and ecology to promote One Health approaches to address the global food safety challenges.

Isolation and characterisation of Brucella melitensis by bacteriological and molecular methods from livestock in North Cyprus

In this study, the isolation, biotyping and molecular characterisation of Brucella melitensis from cattle, sheep and goats in North Cyprus are reported on. A total of 319 raw milk samples obtained from seropositive dairy livestock (190 cattle, 74 sheep and 55 goats) and tissue samples including the liver, spleen and abomasal contents obtained from 32 aborted foetal samples (5 cattle, 18 sheep and 9 goats) were analysed for the presence and characterisation of the agent. B. melitensis was isolated and identified from 90 out of 319 (28.2%) milk and 19 out of 32 (59.4%) foetal samples by conventional bacteriological methods. Identification of all 109 isolates was confirmed by using real-time PCR with genus and species-specific primers. Following the preliminary identification, 27 selected isolates representing various counties and herds were further analysed by conventional methods. Twenty (74.1%) isolates were identified as B. melitensis biovar 1 and seven (25.9%) were identified as B. melitensis biovar 3. The Bruce-ladder multiplex PCR assay revealed that all the isolates were field strains. The results of the present study confirmed the presence of B. melitensis in livestock including the cattle population in North Cyprus. Even though the majority of the samples came from seropositive cattle, Brucella abortus was not isolated in the study. The results also revealed the potential public health risk of brucellosis in livestock emphasising the need of implementing strict control and eradication strategies against the disease in animal populations in order to protect human health.

Molecular Survey of Brucella melitensis Field Isolates using Sequence-Based PCR of Outer Membrane Protein 31

Sequence-based Polymerase Chain Reaction (PCR) has been introduced as an effective and reliable method for bacterial strain typing, which could provide a reliable typing approach for clinical laboratories. This study aimed to describe the reproducibility and performance of the Outer Membrane Protein 31 (Omp31)-based PCR, as a molecular genotyping tool for Brucella melitensis (B. melitensis) typing. The 31 KD outer-membrane protein of Brucella, which encodes the Omp31 gene, can be applied as an antigen to diagnose brucellosis. For this purpose, 146 samples were taken from human blood samples, bovine and camel lymph nodes, as well as sheep and goat aborted fetuses, including fetal kidney, abomasum, liver, lung, spleen, and heart for bacteriological investigation. The molecular detection of the Omp31 and IS711 genes was performed using the isolated B. melitensis (n=14). The sequencing of the Omp31 gene of B. melitensis in the Iranian field isolates was also performed for the whole gene sequencing. The homology of all sequences was then checked with the reported National Center for Biotechnology Information sequences using a basic local alignment search tool for the nucleotide diversity evaluation. The findings revealed that B. melitensis isolates were recovered from 14 examined cases and confirmed by the IS711-based PCR with a PCR product of 731 bp. Moreover, 14 Iranian B. melitensis sequences clustered together as a monophyletic grouping with bootstrap support of 63, and they were closely related to the B. melitensis reference isolates. This Omp31-based phylogenetic placement strongly indicates the monophyletic origin of the Iranian B. melitensis in different animals and human hosts.

Evaluation of in vitro Anti-Brucella Activity and Chemical Composition of Different Geographically Distinct Propolis from Iran

Brucellosis is one of the most important zoonotic diseases in many regions worldwide. This study aimed to investigate the antimicrobial properties of hydro-ethanolic extracts of propolis (EEP) samples collected from six different regions of Iran against five Brucella melitensis (B. melitensis) clinical isolates causing human brucellosis and an antibiotic-resistant B. abortus vaccinal strain (RB51). Brucella clinical isolates were first carefully identified using conventional molecular typing and Brucella bio-typing methods. Different Brucella strains were then confronted with EEPs using the disk-diffusion agar method to evaluate the antimicrobial activity of each propolis extract. Chemical composition of EEPs was then determined using HPLC-DAD, and the main phenolic compounds were quantified. It was found that all EEPs displayed significant antimicrobial activities against Brucella strains, though to varying extents. All tested clinical strains were susceptible to different EEPs with inhibition zones ranging from 18 to 38 mm diameter. Interestingly, the RB51 vaccine strain was more susceptible to EEP6 (from Markazi province), compared to conventional antibiotics used in the treatment of brucellosis. Substantial differences observed in EEP antimicrobial activity could be due to their distinct botanical origins and chemical compositions as confirmed by our HPLC analysis. The promising inhibitory effect of some propolis preparations against a broad spectrum of Brucella strains points to the need for further studies in the context of systematic clinical investigations and opens up the way for the development of natural complements in support of conventional antibiotic therapy.

Occurrence and risk factors of brucellosis among domestic animals: an artificial neural network approach

Brucellosis is a zoonotic infectious disease with a worldwide distribution. This cross-sectional study aimed to determine the occurrence of Brucella in milk and blood samples of ruminants and the importance factors associated with animal brucellosis in Eastern Iran. A total of 200 paired samples, including blood (100) and milk (100), were obtained from the goats, sheep, and cows in Eastern Iran. Serum agglutination (SAT) and 2-mercapto ethanol (2-ME) tests were performed on the sera. A multiplex-polymerase chain reaction (m-PCR) assay was performed to identify the following species of Brucella, including B. abortus biovar 1, 2, 4, 3b, 5, 6, and 9, B. abortus S19, B. melitensis, and B. melitensis Rev.1 vaccine strain. B. abortus RB51 vaccine strain was also investigated in a second PCR assay. Risk factors for infection with Brucella spp. including the effect of abortion, contact with the wild animals, herd type, age, and previous vaccination in predicting blood contamination with B. abortus biovar 1, 2, and 4 were modeled by use of the artificial neural network. A total of 23 samples were seropositive regarding SAT and 2-ME tests. In total, B. abortus was detected in 35% and 15% of blood and milk samples, respectively, by the m-PCR assay. One sample of each of milk and blood was detected to have B. melitensis. Some samples were simultaneously contaminated with two Brucella species or two biovars of B. abortus. B. abortus S19 and B. melitensis Rev.1 vaccine strains were also detected in milk and blood samples. The sensitivity and specificity of the ANN model were 81% and 62%, respectively. In conclusion, B. abortus had higher frequency than B. melitensis in blood and milk samples. ANN determined herd type, previous vaccination, and age of the animal as the largest predictors of blood contamination with B. abortus.

Importance of brucellosis control programs of livestock on the improvement of one health

Brucellosis not only represents an important health restraint on livestock but also causes high economic losses in many developing countries worldwide. Despite considerable efforts made for the control of brucellosis, the disease is still spreading in many regions (such as the Middle East) where it represents one of the most important health hazards impacting both animals and humans. The present review aims to investigate the efficacy of veterinary control programs regarding brucellosis, with a special focus on current prevention, control, and eradication approaches. The reasons for unsuccessful control programs such as the absence of highly effective vaccines and non-certified bulls are also debated, to understand why the prevalence of brucellosis in livestock is not decreasing in many areas despite considerable efforts taken to date. The importance of governmental and regional investment in brucellosis control remains one of the main limiting factors owing to the limited budget allocated to tackle this disease. In this context, one health concept has generated novel comprehensive approaches with multiple economic implications across the livestock industry and public health. However, the implementation of such global preventive strategies appears to be a key issue for many endemic and low-income countries. According to the collected data, epidemiological contexts including management and trade systems along with well-defined agro-ecological zones should be evaluated in brucellosis endemic countries to improve milk production and to enhance the sustainability of the livestock sector at both national and regional levels.

Serological and molecular investigation of human brucellosis in participants of Famenin brucellosis cohort study, Hamadan, Iran

Background and Objectives

Brucella is an intracellular pathogen that causes brucellosis in humans and animals. This study aimed to assess the results of brucellosis seroprevalence among participants of the Famenin brucellosis cohort with molecular investigation technique and determine Brucella-approved species.

Materials and Methods

Following the first phase of the Famenin brucellosis cohort in 2016 which investigated the seroprevalence of brucellosis among 2367 participants in Famenin city, a total of 575 people including all seropositive and some seronegative people were examined again by wright serological tests in 2019. The PCR assay was accomplished on all cases that have wright titers ≥ 1/20 for tracing Brucella DNA using BCSP31 target gene and IS711 locus.

Results

Out of 575 studied cases, 145 people had wright titers ≥ 1/20. The PCR reactions of these 145 blood samples were positive in 63/145 (43.44%) tested samples using primers (B4/B5) for Brucella genus detection. In the second PCR assay using specific-primers for Brucella abortus and Brucella melitensis, 18/63 (28.57%) of the samples were diagnosed as B. abortus, and 18/63 (28.57%) were diagnosed as B. melitensis.

Conclusion

In this study, using the selected specific genes for the diagnosis of Brucella in the genus and species levels, the PCR technique was evaluated as a promising method for the rapid and safe detection of brucellosis besides the serological test for more accurate detection of brucellosis especially in cases that are not definitive.

Isolation of Brucella abortus biovar 1 from human lumbar disc bulging: a case report of brucellar discitis

Background

Brucellosis is an endemic zoonotic disease with rising health and economic concerns in many areas worldwide. Musculoskeletal pains are among the main complications of human brucellosis, which are often difficult to diagnose due to the variability of clinical symptoms. Brucellar discitis is a very disabling problem in some chronic forms of the disease which may lead to serious vertebral and neurological consequences.

Case presentation

In this case report, we reported the isolation of Brucella abortus from lumbar disc bulging in a woman who had rheumatoid arthritis and diabetes mellitus as underlying conditions. The patient had several negative brucellosis serological tests and dorsolumbar pains with urinary incontinence over a 2-month period. The diagnosis was confirmed by magnetic resonance imaging (MRI) examination of lumbar spine as well as disc culture. MRI examination was performed without intravenous contrast and revealed the presence of disc bulging, left foraminal narrowing at L5-S1, left foraminal narrowing, anterolisthesis grade II at L4-L5. The diagnosis was also confirmed by isolation of B. abortus biovar 1 from bulging disc culture. The isolate was characterized by AMOS PCR, Bruce-ladder PCR and biotyping, resulting in the identification of B. abortus from L4-L5 and L5-S1 disc bulging regions. The patient was treated with two drugs i.e. doxycycline and rifampin for 3 months. In the follow-up, in addition to improving the patient’s general condition, low-back pain was also significantly reduced.

Conclusions

MRI, serology, cultural and molecular test along with patient history are important to make a rapid diagnosis of brucellosis’ discitis, thereby decreasing the delay for the brucellosis treatment. The present report suggests that the infection by Brucella spp. should be fundamentally considered among the causative agents of back pain especially in the endemic areas of Brucella infections.

Molecular Detection of Zoonotic Pathogens in the Blood and Tissues of Camels (Camelus dromedarius) in Central Desert of Iran

Dromedary camels (Camelus dromedarius) play a major economic role in many countries in Africa and Asia. Although they are resistant to harsh environmental conditions, they are susceptible to a wide range of zoonotic agents. This study aimed to provide an overview on the prevalence of selected zoonotic pathogens in blood and tissues of camels in central Iran. Blood, liver, portal lymph node, and brain were collected from 100 apparently healthy camels at a slaughterhouse in Qom city to assess the presence of DNA of Brucella spp., Trypanosoma spp., Coxiellaburnetii, and Bartonella spp. PCR products were sequenced bidirectionally and phylogenetic analyses were performed. Eleven percent of camels tested positive for Brucellaabortus (3%) and Trypanosomaevansi (8%). Coxiellaburnetii and Bartonella spp. DNA was not detected. Our data demonstrate that camels from Iran contribute to the epidemiology of some zoonotic pathogens. Performing proper control strategies, such as vaccination of camels and humans in contact with them, test-and-slaughter policy, and education of the general population is necessary for minimizing the risk of zoonotic infection.

A Retrospective Survey of the Abortion Outbreak Event Caused by Brucellosis at a Blue Fox Breeding Farm in Heilongjiang Province, China

Brucellosis is a common zoonosis in China, resulting in abortion in animals. Outbreaks of abortion in blue foxes caused by Brucella infection have rarely been reported. In the present study, 3-5 mL blood samples collected from the femoral veins of 10 abortuses of blue foxes were assessed by RBPT (Rose Bengal plate test) and SAT (serum tube agglutination test) to preliminarily investigate the source of infection for the clustering of abortion events at a blue fox farm in Heilongjiang Province. Screening experiments showed that all 10 blood samples were positive in the RBPT, while only eight blood samples out of the 10 were positive in the SAT. Subsequently, 10 tissue samples (spleen, lungs, stomach contents, and afterbirth) from the same 10 foxes were assessed using AMOS (acronym for B. abortus, melitensis, ovis, and suis)-PCR (polymerase chain reaction), and sequencing analysis was performed on amplification products to verify the results of the serology survey. Results showed a spectral band of ~731 bp in these samples. BLAST showed sequences of AMOS-PCR products in this study to be 100% similar (E = 0.0) to sequences in B. melitensis strain from GenBank. These data preliminarily indicated that the blue fox's outbreak of abortion events was caused by brucellosis via the B. melitensis strain. Then 726 serum samples were tested by RBPT and SAT to determine the prevalence of brucellosis on the farm. A comprehensive epidemiological and reproductive status survey of the infected blue fox population was performed. The seropositive rate was found to be 67.90% (493/726) by RBPT and 41.32% (300/726) by SAT. The technicians had stopped feeding the foxes with chicken carcasses and instead fed them raw ground sheep organs (lungs, tracheae, placentae, and dead sheep fetuses) infected by B. meliteneis strains, and that this change in diet caused the outbreak of abortion events. The high abortion rate (55%) and low cub survival rate (65%) were the most distinctive features of the outbreak; these factors led to severe economic losses. Feeding cooked sheep/goat offal and strict breeding management is necessary for disease prevention.

Bovine brucellosis - a comprehensive review

Brucellosis is a zoonotic disease of great animal welfare and economic implications worldwide known since ancient times. The emergence of brucellosis in new areas as well as transmission of brucellosis from wild and domestic animals is of great significance in terms of new epidemiological dimensions. Brucellosis poses a major public health threat by the consumption of non-pasteurized milk and milk products produced by unhygienic dairy farms in endemic areas. Regular and meticulous surveillance is essentially required to determine the true picture of brucellosis especially in areas with continuous high prevalence. Additionally, international migration of humans, animals and trade of animal products has created a challenge for disease spread and diagnosis in non-endemic areas. Isolation and identification remain the gold standard test, which requires expertise. The advancement in diagnostic strategies coupled with screening of newly introduced animals is warranted to control the disease. Of note, the diagnostic value of miRNAs for appropriate detection of B. abortus infection has been shown. The most widely used vaccine strains to protect against Brucella infection and related abortions in cattle are strain 19 and RB51. Moreover, it is very important to note that no vaccine, which is highly protective, safe and effective is available either for bovines or human beings. Research results encourage the use of bacteriophage lysates in treatment of bovine brucellosis. One Health approach can aid in control of this disease, both in animals and man.

Investigation of Mutations in the Rifampin-Resistance-Determining Region of the rpoB Gene of Brucella melitensis by Gene Analysis

Background: RNA polymerase beta subunit (rpoB) gene analysis in bacterial communities is known as a method for determining rifampin sensitivity and genetic diversity among Brucella spp. Detection of antibiotic resistance among Brucella isolates can be a critical approach to control brucellosis. However, rpoB gene analysis of Brucella melitensis for assessing rifampicin resistance has not yet been performed in Iran, which is considered an endemic area for brucellosis. Objectives: The aim of this study was to analyze the whole sequence of rpoB genes of different B. melitensis isolates from humans to identify the single-nucleotide polymorphisms (SNPs) and mutations related to rifampin resistance and to analyze the genetic diversity of these bacteria in Iran. Methods: Between 2017 and 2019, a total of 156 blood samples along with 12 synovial fluid specimens were collected from brucellosis patients in different Iranian provinces and subjected to bacterial culture in Brucella selective media. Brucella identification was carried out using classical biotyping and molecular examinations. Polymerase chain reaction (PCR)-based amplification of the rpoB gene was performed by specific rpoB primers for whole gene sequencing. The antimicrobial susceptibility of Brucella isolates was assessed using disk diffusion susceptibility tests and minimal inhibitory concentration (MIC) methods. The presence of rifampin-binding sites and SNPs were investigated through rpoB whole gene sequencing. Results: Clinical B. melitensis isolates were obtained from blood (13) and synovial fluid (1) samples of patients from different regions of Iran. The results of MIC and disk diffusion susceptibility tests showed that all the isolates were sensitive to rifampin except for one isolate showing intermediate rifampin resistance based on the standards defined for slow-growing bacteria by the Clinical and Laboratory Standards Institute (CLSI). Gene analysis for identifying the mutations related to rifampin resistance and investigating genetic diversity showed that none of the B. melitensis isolates had missense mutations, confirming the susceptibility of all the studied isolates to rifampin. Conclusions: The present study revealed that rpoB gene analysis could be used for the efficient and precise identifying of the mutations related to rifampin resistance, investigating rifampin binding sites, and genotyping Brucella species. Furthermore, the identification of B. melitensis isolates with intermediate resistance to rifampicin highlighted the importance of periodically carrying out antibiotic susceptibility testing. The molecular detection of rpoB mutations in different Brucella isolates may help to prevent the spread of rifampin-resistant Brucella spp. among humans and livestock.