Differentiation of Brucella abortus bv. 1, 2, and 4, Brucella melitensis, Brucella ovis, and Brucella suis bv. 1 by PCR

Potential role of peste des petits ruminants virus in small ruminant abortions

The aim of the present study was to investigate the frequency, genetic variability, and phylogeny of the peste des petits ruminants virus (PPRV) in ovine and caprine fetuses. During 2014 and 2017, a total of 1054 embryos/fetuses were collected in Turkey. A real-time RT-PCR assay was used for the detection of the PPRV RNA. Genetic characterization and phylogenetic analysis of the PPRV field isolates were conducted by sequencing fusion (F) protein and nucleoprotein (N) gene segments. Samples were also collected from ewes (n = 83) and nanny goats (n = 3) that had aborted and whose embryos/fetuses were found to be PPRV positive. PPRV positive embryos/fetuses were also tested for the presence of Listeria monocytogenes, Campylobacter spp., Coxiella burnetii, Chlamydophila abortus, Brucella spp., akabane virus, aino virus, bluetongue virus, border disease virus, bovine viral diarrhea virus, Cache Valley virus, and Schmallenberg virus. PPRV RNA was detected in 123 (11.7 %) of the 1054 embryos/fetuses, 78 of the 83 (94 %) ewes and 3 (100 %) nanny goats. Border disease virus RNA and Chlamydophila abortus DNA were detected in 7 and 12 PPRV positive sheep fetuses, respectively, while other bacterial and viral agents were not detected. Phylogenetically, the field isolates in this study belong to lineage IV, and compared to other strains of lineage IV considered in this study, they showed 1 and 5 new amino acid substitutions in the F and N gene sequences, respectively. The results of the study suggest that PPRV plays an important role in abortion. Therefore, PPRV needs to be taken into consideration in sheep and goats abortions.

Draft genome sequences of Brucella melitensis from human and animal sources in India

We present the draft genome sequences of 23 Brucella melitensis isolates derived from human and animal sources across India with genome size predominantly at 3.207 M and uniform GC content (57.24%) across isolates. The accession numbers and detailed sequencing data enhance the utility of this resource for further genomic studies.

Whole Genome Sequence Analysis of Brucella spp. from Human, Livestock, and Wildlife in South Africa

Brucellosis is an economically important zoonotic disease affecting humans, livestock, and wildlife health globally and especially in Africa. Brucella abortus and B. melitensis have been isolated from human, livestock (cattle and goat), and wildlife (sable) in South Africa (SA) but with little knowledge of the population genomic structure of this pathogen in SA. As whole genome sequencing can assist to differentiate and trace the origin of outbreaks of Brucella spp. strains, the whole genomes of retrospective isolates (n = 19) from previous studies were sequenced. Sequences were analysed using average nucleotide identity (ANI), pangenomics, and whole genome single nucleotide polymorphism (wgSNP) to trace the geographical origin of cases of brucellosis circulating in human, cattle, goats, and sable from different provinces in SA. Pangenomics analysis of B. melitensis (n = 69) and B. abortus (n = 56) was conducted with 19 strains that included B. abortus from cattle (n = 3) and B. melitensis from a human (n = 1), cattle (n = 1), goat (n = 1), Rev1 vaccine strain (n = 1), and sable (n = 12). Pangenomics analysis of B. melitensis genomes, highlighted shared genes, that include 10 hypothetical proteins and genes that encodes for acetyl-coenzyme A synthetase (acs), and acylamidase (aam) amongst the sable genomes. The wgSNP analysis confirmed the B. melitensis isolated from human was more closely related to the goat from the Western Cape Province from the same outbreak than the B. melitensis cattle sample from different cases in the Gauteng Province. The B. melitensis sable strains could be distinguished from the African lineage, constituting their own African sub-clade. The sequenced B. abortus strains clustered in the C2 lineage that is closely related to the isolates from Mozambique and Zimbabwe. This study identified genetically diverse Brucella spp. among various hosts in SA. This study expands the limited known knowledge regarding the presence of B. melitensis in livestock and humans in SA, further building a foundation for future research on the distribution of the Brucella spp. worldwide and its evolutionary background.

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.

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.

Effects of Pregnancy Prevention on Brucella abortus Shedding in American bison (Bison bison)

Products of parturition are the predominant source of Brucella abortus for transmission in bison (Bison bison). Our objective was to assess whether preventing pregnancy in Brucella-seropositive bison reduced B. abortus shedding. Brucella-seropositive and -seronegative bison from Yellowstone National Park, Wyoming, USA were used in a replicated experiment. Each of two replicates (rep1, rep2) included a group of seropositive females treated with a single dose of gonadotropin-releasing hormone-based immunocontraceptive (Treatment rep1, n=15; Treatment rep2, n=20) and an untreated group (Control rep1, n=14; Control rep2, n=16) housed separately. Seronegative sentinel females were placed in each group to monitor horizontal transmission. Seronegative males were co-mingled for breeding each year. Pregnant females were removed from treatment groups in the first year, but not thereafter. Each January-June we monitored for B. abortus shedding events-any parturition associated with culture-positive fluids or tissues. We analyzed probability of shedding events using a negative binomial generalized linear mixed model fit by maximum likelihood using Laplace approximation. Over 5 yr, we observed zero shedding events in Treatment rep1 vs. 12 in Control rep1. All five Control rep1 sentinels but zero (0/5) Treatment rep1 sentinels seroconverted. In the second replicate, Treatment rep2 had two shedding events over 3 yr and Control rep2 had five events over 2 yr. Sentinels in both Control rep2 (3/6) and Treatment rep2 (5/6) seroconverted by trial endpoint. Treatment rep1 showed a reduced shedding probability relative to Control rep1, Treatment rep2, and Control rep2 (log odds value -25.36 vs. -1.71, -1.39, and -0.23, respectively). Fixed effect predictor covariates, year and age, had no explanatory value. These data suggest that successful contraception of brucellosis-seropositive female bison prevents shedding of B. abortus by individual animals. However, contraceptive treatment may or may not sufficiently reduce disease transmission to reduce brucellosis prevalence in an affected herd.

Polyphasic Characterization of Brucella spp. in Livestock Slaughtered from Abattoirs in Eastern Cape, South Africa

In livestock, brucellosis is mainly an asymptomatic disease except when abortion occurs; therefore, two serological tests are used for diagnosis as no single test is suitable. Abattoir samples enable a combination of culture, molecular, and serological tests to detect brucellosis. This study assessed Brucella-specific PCR (ITS-PCR) to detect brucellosis and to conduct a molecular characterization of Brucella spp. isolated from PCR-positive livestock (n = 565) slaughtered at abattoirs and the appropriate sample tissue(s). ITS-PCR detected Brucella DNA in 33.6% of cattle, 14.5% of sheep, and 4.7% of pig tissues. Impure Brucella cultures from PCR-positive tissues were 43.6% (44/94) of cattle, 51.7% (15/29) of sheep, and 50% (2/4) of pigs with predominantly B. abortus identification with AMOS-PCR and low isolation of mixed B. abortus and B. melitensis in all species. In cattle, 33% of isolates were from lymph nodes, while in sheep 38.0% were from the liver and kidney and only from tonsils in pigs (2/4). Brucella infections identified with AMOS-PCR were present in seropositive and mainly seronegative (75.6-100%) livestock with the potential to cause brucellosis during pregnancy or breeding. This study demonstrated the value of the polyphasic approach, especially with chronic infections and the potential risk of these asymptomatic animals.

Epidemiological changes and molecular characteristics of Brucella strains in Ningxia, China

Objective

Human brucellosis causes serious public health concerns in Ningxia, China.

Methods

This study employed epidemiological, bacteriological, and multiple-locus variable-number tandem repeat analysis (MLVA) methods to conduct an epidemiological investigation, which is necessary for devising tailored control strategies.

Results

Between 1958 and 2022, 29,892 cases were reported, with an average annual number of cases and incidence of 467 and 7.1/100,000, respectively. The epidemic situation gradually worsened, with cases escalating from 26 cases in 2005 to 6,292 in 2022, with the incidence rate rising from 0.441 in 2005 to 86.83 in 2022. Geographically, the disease spread from a single affected county in 2004 to encompass all 22 counties in 2022. Yanchi County had the highest incidence, followed by the Hongsibao and Tongxin counties. These data suggest that Brucella infection has become a rampant regional concern in human brucellosis. Between 1958 and 2019, a total of 230 Brucella strains were identified across four studied hosts. These strains comprised four species with 12 biovars, including B. melitensis bv. 1, bv. 2, bv. 3, B. abortus bv. 1, bv. 3, bv. 4, bv. 5, bv. 6, bv. 7, B. suis bv. 1 and bv. 3, and B. canis. These data highlight the high species/biovars and host diversity of the Brucella population, posing a substantial challenge to brucellosis surveillance. There was an apparent transition from multiple species/biovars historically to the current dominance of a single species, B. melitensis, emphasizing the requirement for strengthening surveillance of B. melitensis. Genotypes 42 and 116, constituting 96.2% of the total number of genotypes, predominated in panel 1 and MLVA-11, indicating that all strains belong to the East Mediterranean lineage. MLVA cluster analysis revealed persistent transmission of dominant circulating genotypes, presenting an epidemic pattern characterized primarily by epidemiologically related cases with a few sporadic cases. Strains in this study exhibited high genetic homogeneity with strains from the Northwest, and those from Kazakhstan and Mongolia.

Conclusion

The epidemic situation of human brucellosis has gradually worsened; the rampant epidemic of the disease has become a regional concern. The present study highlights that implementing the of targeted surveillance and intervention strategies is urge.

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.

Genotypic peculiarities of a human brucellosis case caused by Brucella suis biovar 5

Human brucellosis cases are rare in non-endemic countries, such as Germany, where infections are predominantly caused by Brucella melitensis. The German National Reference Laboratory for Bovine, Porcine, Ovine and Caprine Brucellosis received a suspected Brucella sp. isolate from a patient for identification. Bacteriological tests and PCR-based diagnostics showed the isolate to be B. suis, but did not yield cohesive results regarding the biovar. Whole genome sequencing and subsequent genotyping was employed for a detailed characterization of the isolate and elucidating the reason for failure of the diagnostic PCR to correctly identify the biovar. The isolate was found to be B. suis bv. 5, a rare biovar with limited geographical distribution primarily found in the Northern Caucasus. Due to a deletion in one of the target regions of the diagnostic PCR, the isolate could not be correctly typed. Based on in silico genotyping it could be excluded that the isolate was identical to one of the B. suis bv. 5 reference strains. Here, we report a rare case of a B. suis bv. 5 field isolate. Furthermore, by reporting this finding, we want to make practitioners aware of possible misinterpretation of PCR results, as it cannot be excluded that the detected deletion is common among the B. suis bv. 5 community, as there is currently a lack of field isolates.

Brucella melitensis: Divergence Among Indian Strains and Genetic Characterization of a Strain Isolated from Cattle

Brucella melitensis primarily affects sheep, goats and is associated with brucellosis in humans, which is one of the world's most widespread neglected zoonotic disease. The current study attempted the determination of genetic diversity through comparative genome analysis of B. melitensis strains reported from India with other countries. The study also reports the isolation and identification of B. melitensis BMNDDB8664 from a cow with a history of abortion, whole-genome sequencing (WGS), determination of virulence factors, genotyping, and comparative genome analysis. Multilocus sequence typing, Multiple locus variable number of tandem repeats analysis (MLVA), and WGS based phylogeny revealed the predominance of ST-8 and genotypes (116 and II respectively) that clustered to the East Mediterranean lineage. Identification of hitherto unreported genotypes by MLVA also indicated the existence and circulation of West Mediterranean and American lineages in India. Though the AMOS-PCR results suggest the BMNDDB8664 isolate as Brucella abortus, the outcomes from multiplex PCR, ribosomal multilocus sequence typing, and WGS analysis confirmed it as B. melitensis. The analysis revealed the presence of adeF gene (aids conferring resistance to fluoro-quinolone and tetracyclines). The isolate lacked two important T4SS genes virB2 and virB7 genes (roles in infection and rifampicin resistance respectively) and also lacked the Brucella suis mprF gene that aids intracellular survival. Further, BMNDDB8664 lacked some of the genes associated with LPS synthesis (wbkB, wbkC) and transport (wzm, wzt) and hence, is most likely a rough strain. WGS-based phylogenetic analysis revealed close genetic relatedness of this BMNDDB8664 with a sheep isolate and two human isolates. The results prompt systematic, broad-based epidemiological studies on brucella infection at the species level. For effective control of human brucellosis, a concerted One Health approach with studies encircling the identification of aetiology at species, strain level to find their prevalence, spread, and inter-host transmission patterns need to be understood, for better design and implementation of effective control strategies in India and other endemic regions.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12088-023-01081-w.

Seroprevalence, and molecular detection of Brucella abortus in cattle tissues from an abattoir in Namibia

Brucellosis is a worldwide zoonosis that is endemic in Namibia. This study estimated seroprevalence of brucellosis, and determined the presence of Brucella infection in slaughtered cattle using the genus-specific 16-23S rRNA interspacer PCR (ITS-PCR), and the species-specific AMOS-PCR. Between December 2018 and May 2019, sera (n = 304), pooled lymph nodes (n = 304), and individual spleen (n = 304) were collected from slaughtered cattle from 52 farms. Sera were tested for anti-Brucella antibodies using the Rose Bengal test (RBT), and the complement fixation test (CFT). Seroprevalence was 2.3% (7/304) (RBT) and 1.6% (5/304) (CFT). Prevalence of positive herds was 9.6% (5/52). Lymph node (n = 200) and spleen (n = 200) samples from seronegative cattle tested negative for Brucella spp. DNA on ITS-PCR, but Brucella spp. DNA was detected in lymph nodes (85.7%, 6/7) and spleen (85.7%, 6/7) from RBT positive cattle. ITS-PCR confirmed isolates from lymph node (51.4%, 4/7) and spleen (85.7%, 6/7) as Brucella spp.; while AMOS-PCR and Brucella abortus species specific (BaSS) PCR confirmed the isolates as Brucella abortus, and field strains, respectively. Provision of adequate protective gear, and the promotion of brucellosis awareness among abattoir workers is recommended to prevent zoonotic infection.

Whole-genome sequencing for genetic diversity analysis of Iranian Brucella spp. isolated from humans and livestock

Brucellosis is one of the most common zoonoses in the Middle East. It is causing economic losses to the livestock industry and has a great public health concern. Little is known about the genetic diversity and distribution of brucellae in Iran. Therefore, forty Brucella spp. strains (B. abortus and B. melitensis) isolated from animals and humans were analyzed by whole genome sequencing (WGS) technology using single nucleotide polymorphism (SNP) analysis and core genome multilocus sequence typing (cgMLST). Brucella isolates were obtained from lymph nodes (cows and camels), milk (cows, camels and sheep), and aborted foetus samples (sheep and goats), as well as cerebrospinal fluid and blood of humans. The isolates were originating from thirteen provinces of Iran and isolated between 2015 and 2020. According to in-silico MLST, ST8 and ST2 were the most frequent sequence types in B. melitensis and B. abortus, respectively. Based on phylogeographic reconstruction using cgSNP analysis, the investigated Iranian B. melitensis strains belonged to the American and Mediterranean lineages of the B. melitensis phylogeny. Furthermore, cgSNP analysis revealed a similarity between Iranian B. abortus isolates and strains from Iraq and Egypt. Therefore, the origin of the Iranian strains can be suggested to be strains from neighboring and Middle East countries. Moreover, cgMLST analysis showed that the Iranian B. melitensis strains were closely relative to strains recovered from sheep and humans in Iraq, Afghanistan, Syria, Turkmenistan, and Pakistan. In the current panel of strains, cgMLST and cgSNP analysis provided an appropriate and accurate tool for effective traceback analyses for Brucella spp. from Iran. The results of cgSNP and cgMLST helped to understand the geographic distribution and interspecies transmission of Iranian strains and highlight the importance of specific brucellosis control measures in Iran with regard to the One-Health approach.

Genomic distribution of the insertion sequence IS711 reveal a potential role in Brucella genome plasticity and host preference

The Insertion Sequence 711 (IS711) is linked to the Brucella genus. Mapping the genomic distribution of IS711 can help understand this insertion element's biological and evolutionary role. This work aimed to delineate the genomic distribution of the IS711 element and to study its association with Brucella evolution. A total of 124 genomes representing 9 Brucella species were searched using BLASTn sequence alignment tool to identify complete and truncated copies of IS711. Based on the genomic context, each IS711 locus was assigned a code using the initial letters of its neighboring genes. Various tools were used to annotate the neighboring genes and determine the shared synteny around orthologous IS711 loci. The tool Islandviewer 4 was used to scan for genomic islands. The Codon Tree method was used to build phylogenetic trees of B. melitensis, B. abortus, and B. suis genomes. The phylogenetic trees of the three species were analyzed, taking into account the genomic distribution patterns of IS711. The result of IS711 frequency analysis showed a relatively conserved number of copies/genome for the different species and for some biovars. The analysis showed that Brucella species with a relatively low IS711 copy number (4-8 copies/genome) are linked to domestic animals as primary hosts and have potential for zoonotic transmission. However, species with a relatively higher copy number (12-30 copies/genome) are less zoonotic and tend to be linked with wild animals as primary hosts. Analyzing the genomic distribution map of IS711 loci showed several unique patterns of IS711 distribution that are correlated with the evolution of Brucella species and biovars. The results also showed that 46.2% of the conserved IS711 elements are located within genomic islands. Based on our results and previous data, we postulate a model explaining the IS711 role in Brucella evolution. We assume that during the transition from a free-living to an intracellular lifestyle, a descendant of the Brucella genus had acquired a progenitor sequence of the IS711. Subsequently, a burst in IS711 transposition occurred. This parasitic expansion can be deleterious and has to be counteracted by evolutionary forces to prevent lineage extension and to promote adaptation to host. Similar to other plasmid-free pathogenic α-Proteobacteria bacteria, the balance of expansion and reduction of insertion elements could be one of the mechanisms to control genome reduction and streamlining. We hypothesize that the IS711-mediated genomic changes and other small sequence nucleotide changes in specific orthologous genes could significantly contribute to Brucella's evolution and adaptation to different animal hosts.

Whole-genome sequencing (WGS) analysis of Brucella suis biovar 2 isolated from domestic pigs in Egypt for epidemiological and genetic diversity tracing

In the current study, 14 Brucella suis biovar 2 (B. suis bv 2) strains isolated from slaughter pigs in Cairo were sequenced using Illumina technology to investigate genetic diversity, antimicrobial resistance (AMR) genes, and virulence-associated determinants. These strains were the first B. suis bv 2 isolates from Egypt. To place them in a global context, 92 genomes of B. suis were retrieved from the NCBI database and used for comparison. The in-silico analysis of MLST showed that all isolates have ST16. No resistome but 43 virulomes have been found without differences in distribution. The cgMLST classified the Egyptian B. suis strains into a complex type (CT) encompassing four distinct cgMLST sequence types. The closest relatives were strain B. suis 94/11 of an unknown origin and a Danish strain. Whole-genome sequencing analysis proved low diversity of Egyptian B. suis isolates; thus, a single introduction event is assumed. Investigation of a large number of B. suis isolates from different governorates is required to tailor control measures to avoid further spread.

First seroprevalence and molecular identification report of Brucella canis among dogs in Greater Cairo region and Damietta Governorate of Egypt

Background and Aim

Given the rise in stray and imported dogs in Egypt over the past 5 years, it is surprising that no report of Brucella canis infection in dogs or humans has been documented in Egypt's published papers. This study aimed to detect the presence of antibodies against the rough (B. canis) and smooth Brucellae among dogs in Egypt and to characterize the Brucella species circulating in dogs.

Materials and Methods

Blood samples (n = 449) were collected from owned and stray dogs in the Greater Cairo region (n = 309) and Damietta governorate (n = 140). The apparent, true, and total seroprevalence of canine brucellosis caused by B. canis infection were calculated using the 2-mercaptoethanol tube agglutination test (2-ME TAT) and rapid slide agglutination test (RSAT). We used the rose Bengal test (RBT) and the buffered acidified plate antigen test (BAPAT) to check the serum samples from dogs for the presence of antibodies against smooth Brucellae. Three polymerase chain reaction (PCR) assays - Bruce-ladder PCR, B. canis species-specific PCR (BcSS-PCR), and Abortus Melitensis Ovis Suis (AMOS)-PCR - were used to determine the Brucella species in the buffy coats of the serologically positive dogs.

Results

The overall apparent and true prevalence of B. canis infection in dogs were estimated to be 3.8% and 13.2%. The estimated true prevalence in stray dogs (15%) was higher than in owned dogs (12.5%). The BAPAT and the RBT using smooth antigens revealed that 11 (2.4%) and 9 (2%) were positive. Bruce-ladder PCR targeting eryC, ABC, and Polysaccharide deacetylase genes was able to identify B. canis in nine out of 17 buffy coat samples. AMOS-PCR identified the eight undetermined Brucella species by Bruce-ladder PCR as Brucella abortus (n = 4) and Brucella melitensis (n = 4). To exclude the presence of Brucella suis, a one-step species-specific BcSS-PCR was performed and specifically amplified all B. canis DNA (n = 9) the same as did the Bruce-ladder PCR.

Conclusion

To the best of our knowledge, this is the first report of B. canis detection in dogs in Egypt. Molecular identification of B. abortus and B. melitensis in the Egyptian canines highlights the role of stray dogs in brucellosis remerging in Brucellosis-free dairy farms. Brucella canis infection can be diagnosed specifically with the one-step BcSS-PCR. The obtained results set-an-alarm to the veterinary authorities to launch plans to control this disease in dogs.

Human brucellosis in Baringo County, Kenya: Evaluating the diagnostic kits used and identifying infecting Brucella species

Human brucellosis diagnosis has been a challenge in Brucella-endemic areas. In Kenya, diagnosis is usually carried out using Febrile Brucella Antigen agglutination test (FBAT) whose performance is not well documented. This paper reports on the sensitivity and specificity of the FBAT used for brucellosis diagnosis on blood samples/serum collected in three healthcare facilities in Baringo County, Kenya, and on Brucella species present in the study area. The FBAT test results at the hospitals were used to guide patient management. Patients who visited the hospital's laboratory with a clinician's request for brucellosis testing also filled a questionnaire to assess knowledge and attitudes associated with transmission of the disease in the study area. The remaining serum samples were tested again using FBAT and Rose Bengal Plate Test (RBPT) within a month of blood collection at the University Nairobi Laboratory. The two rapid tests were then compared, with respect to brucellosis diagnostic sensitivity and specificity. To identify infecting Brucella species, a proportion 43% (71/166) of the blood clots were analyzed by multiplex polymerase chain reaction (PCR) using specific primers for B. abortus, B. melitensis, B. ovis and B. suis. Out of 166 serum samples tested, 26.5% (44/166) were positive using FBAT and 10.2% (17/166) positive using RBPT. The sensitivity and specificity of FBAT compared to RBPT was 76.47% and 71.19%, respectively while the positive and negative predictive values were 29.55% and 96.72%, respectively. The FBAT showed higher positivity then RBPT. The difference in sensitivity and specificity of FBAT and RBPTs was relatively low. The high FBAT positivity rate would be indication of misdiagnosis; this would lead to incorrect treatment. Brucella abortus was detected from 9.9% (7/71) of the blood clots tested; no other Brucella species were detected. Thus human brucellosis, in Baringo was mainly caused by B. abortus.

Molecular characterization and antimicrobial susceptibility of human Brucella in Northeast China

Introduction

Northeast China has always been an area with severe brucellosis prevalence. This study will identify Brucella in Northeast China and test its resistance to antibiotics, in order to clarify its resistance mechanism. Brucella is a widespread and highly pathogenic bacteria that poses serious threats to public health and animal husbandry.

Methods

In this study, 61 Brucella isolates were identified by abortus-melitensis-ovis-suis polymerase chain reaction (AMOS-PCR) for biotypes and epidemic potential was clarified by multi-locus sequence analysis. Whole-genome sequencing (WGS) was performed and the antibiotic susceptibility of the Brucella strains against 13 antibiotics was detected with the use of E-test strips.

Results

The results showed that all of the isolates were Brucella melitensis ST8, group CC4 with little genetic variation and obvious geographical characteristics. All 61 Brucella isolates were sensitive to doxycycline, tetracycline, minocycline, levofloxacin, ciprofloxacin, gentamicin, and streptomycin, while 24.6%, 86.9%, 65.6%, 27.9%, 3.3%, and 1.6% were resistant to rifampin, azithromycin, cefepime, cefoperazone/sulbactam, cefotaxime, and meperidine/sulfamethoxazole, respectively. This is the first report of cephalosporin-resistant B. melitensis in China. The WGS results indicated that about 60% of the antibiotic resistance genes were associated with efflux pumps (mainly the resistance nodulation division family).

Discussion

Brucellosis is usually treated with antibiotics for several months, which can easily lead to the emergence of antibiotic resistance. To ensure the effectiveness and safety of antibiotics for treatment of brucellosis, continuous surveillance of antibiotic susceptibility is especially important.

Investigation of selected bacterial agents causing sheep abortion in the Van Province by RT-PCR and histopathological methods

Abortion causes significant economic losses in the sheep industry. Determination of the aetiology is important in dealing with abortions. The present study was aimed to identify selected important bacterial pathogens in the abortion cases of sheep. A total of 113 samples (105 aborted sheep foetuses, 4 placentas, and 4 vaginal swab samples) from 85 different sheep flocks were examined by real-time PCR (RT-PCR) regarding Chlamydia (C.) spp., C. abortus, Brucella (B.) spp., B. melitensis, Salmonella (S.) spp., S. Abortusovis, Coxiella (C.) burnetii, Listeria (L.) spp., L. monocytogenes, and Campylobacter spp. All cases that were found to be positive for bacterial agents by RT-PCR, were examined pathologically. Tissue samples of foetuses that were found to be positive for B. melitensis and L. monocytogenes by RT-PCR were also investigated immunohistochemically. A total of 35 (30.9%) samples were found to be positive by RT-PCR, with 15 (42.8%), 9 (25.7%), 5 (14.2%), 4 (11.4%), 1 (2.8%), and 1 (2.8%) of them being identified as C. abortus, B. melitensis, S. Abortusovis, C. burnetii, L. monocytogenes and Campylobacter spp., respectively. The presence of the antigen was confirmed also immunohistochemically in the cases with B. melitensis and L. monocytogenes. As a consequence, C. abortus was found to cause the highest rate of sheep abortion cases, which should be taken into account when implementing control measures in epidemiological investigations.

First report and whole-genome sequencing of Pseudochrobactrum saccharolyticum in Latin America

The Brucellaceae family comprises microorganisms similar both phenotypically and genotypically, making it difficult to identify the etiological agent of these infections. This study reports the first isolation, identification, and characterization of Pseudochrobactrum saccharolyticum (strain 115) from Latin America. Strain 115 was isolated in 2007 from a bovine in Brazil and was initially classified as Brucella spp. by classical microbiological tests and bcsp31 PCR. The antimicrobial susceptibility of strain 115 was tested against drugs used to treat human brucellosis by minimal inhibitory concentration test. Subsequently, the whole genome of the strain was sequenced, assembled, and characterized. Phylogenetic trees built from 16S rRNA and recA gene sequences enabled the classification of strain 115 as Pseudochrobactrum spp. Phylogenomic analysis using Single Nucleotide Polymorphisms and Average Nucleotide Identity allowed the classification of the strain as P. saccharolyticum. Additionally, a Tetra Correlation Search identified one related genome from the same species, which was compared with strain 115 by analyzing genomic islands. This is the first identification and whole-genome sequence of P. saccharolyticum in Latin America and highlights a challenge in the diagnosis of bovine brucellosis, which could be solved by including the sequencing of 16S rRNA and recA genes in routine diagnostics.

First record of the human infection of Brucella melitensis in Kyrgyzstan: evidence from whole-genome sequencing-based analysis

BACKGROUND

Brucellosis, a zoonosis mainly transmitted by consumption of unpasteurized dairy products as well as direct contact with infected animals, is endemic in Kyrgyzstan. However, Brucella species in humans have not been investigated and the origin of the disease remains poorly known in wide parts of Сentral Asia. Thus, molecular characterization of the circulating strains is a critical first step in understanding Brucella diversity in the country.

METHODS

In this study, isolates were collected from patients with suspected brucellosis from different regions in Kyrgyzstan between 2019 and 2020. The detection and identification of Brucella was carried out by Bruce-ladder PCR. Next generation sequencing was used to sequence the 89 Brucella isolates, which were genotyped by cgSNP and cgMLST to identify epidemiological connection between Brucella isolates as well as placing them in the context of the global Brucella phylogeny.

RESULTS

The Brucella strains isolated from all regions of Kyrgyzstan were identified as B. melitensis. Based on cgSNP analysis, 18 sequence types were differentiated. The highest numbers of different sequence types were found in Batken (n = 8), Osh (n = 8) and Jalal-Abad (n = 6) oblasts. According to cgSNP and cgMLST analyses, different B. melitensis lineages circulate in Kyrgyzstan, all of them belonging to the Eastern Mediterranean group of the global Brucella phylogeny with the highest similarity to strains from Turkmenistan, Iran and Turkey.

CONCLUSION

In the present study, B. melitensis was identified as a causative agent of human brucellosis in Kyrgyzstan and different lineages could be identified. Since this study focused on isolates of human origin, the identity of Brucella species and lineages circulating among animal populations remains elusive. Implementing culture techniques and use of most recent molecular, bioinformatic and epidemiological tools are needed to set up a One Health approach to combat brucellosis in Kyrgyzstan. Further, other Сentral Asian countries need to take part in this effort as brucellosis is a transboundary disease in these regions.

Seroprevalence of brucellosis and molecular characterization of Brucella spp. from slaughtered cattle in Rwanda

Bovine brucellosis is endemic in Rwanda, although, there is a paucity of documented evidence about the disease in slaughtered cattle. A cross-sectional study was conducted in slaughtered cattle (n = 300) to determine the seroprevalence of anti-Brucella antibodies using the Rose Bengal Test (RBT), and indirect enzyme-linked immunosorbent assay (i-ELISA). Corresponding tissues were cultured onto a modified Centro de Investigación y Tecnología Agroalimentaria (CITA) selective medium and analysed for Brucella spp. using the 16S-23S ribosomal interspacer region (ITS), AMOS, and Bruce-ladder PCR assays. The seroprevalence was 20.7% (62/300) with RBT, 2.9% (8/300) with i-ELISA, and 2.9% (8/300) using both tests in series. Brucella-specific 16S-23S ribosomal DNA interspace region (ITS) PCR detected Brucella DNA in 5.6% (17/300; Brucella culture prevalence). AMOS-PCR assay identified mixed B. abortus and B. melitensis (n = 3), B. abortus (n = 3) and B. melitensis (n = 5) while Bruce-ladder PCR also identified B. abortus (n = 5) and B. melitensis (n = 6). The gold standard culture method combined with PCR confirmation identified 5.6% Brucella cultures and this culture prevalence is higher than the more sensitive seroprevalence of 2.9%. This emphasizes the need to validate the serological tests in Rwanda. The mixed infection caused by B. abortus and B. melitensis in slaughtered cattle indicates cross-infection and poses a risk of exposure potential to abattoir workers. It is essential to urgently strengthen a coordinated national bovine brucellosis vaccination and initiate a test-and-slaughter program that is not presently applicable in Rwanda.

Molecular characterization of Brucella species detected from clinical samples of cattle and buffaloes

The present study was undertaken for molecular characterization of Brucella species of cattle and buffaloes. Clinical samples (1145) of unvaccinated cattle and buffaloes (200 blood samples, 710 sera, 190 vaginal swabs, 20 abomasal contents of foetus, 25 foetal tissues) and 146 blood samples of vaccinated animals were collected from dairy farms in and around Mumbai and Pune region. These samples were processed for isolation of Brucella organisms and further characterized by PCR and sequencing. A total of 26 (11.06%) Brucella isolates were recovered from 235 samples. Also, 5 isolates received from human cases were included in the study. BCSP 31 PCR showed an amplicon of 223 bp in all 31 isolates, 123 (61.5%) blood samples, 123 (64.73%) vaginal swabs and 27 (60%) aborted foetal material. IS711/AB and BM PCR showed an amplicon of 498 bp and 731 bp in 17 and 14 isolates, 42 (21%) and 38 (19%) blood samples, 43 (22.63%) and 34 (17.89%) vaginal swabs, while 7(15.55%) and 6 (13.33%) aborted foetal material, respectively. The phylogenetic analysis detected the ancestral origin of the organism. Rapid and correct diagnosis of brucellosis and vaccination is important to eradicate the disease. The molecular methods used in the present study speed up the diagnosis of the disease.

Molecular characterization of Brucella spp. from seropositive herds of cattle farmed at the wildlife-livestock-human interface in Rwanda

Seroprevalence studies showed that brucellosis is prevalent in cattle in Rwanda with no recent study on the characterization of Brucella spp. Therefore, this study aimed to characterize Brucella spp. in seropositive herds of cattle farmed at the wildlife–livestock–human interface. Whole blood samples (n = 118), milk (n = 41), and vaginal swabs (n = 51) were collected from 64 seropositive herds. All samples (n = 210) were inoculated onto modified Centro de Investigacion y Tecnologia Agroalimentaria (CITA) selective medium. Cultures were analyzed to detect Brucella spp. using 16S−23S ribosomal DNA interspacer region (ITS) PCR, the Brucella cultures were speciated using AMOS and Bruce-ladder PCR assays. Brucella spp. were detected in 16.7% (35/210) of the samples established from the samples using ITS-PCR. The AMOS PCR assay identified mixed Brucella abortus and B. melitensis (n = 6), B. abortus (n = 7), and B. melitensis (n = 1) from cultures from blood samples; mixed B. abortus and B. melitensis (n = 1) and B. abortus (n = 4) from cultures from milk samples; mixed B. abortus and B. melitensis (n = 6), B. abortus (n = 8), and B. melitensis (n = 1) from cultures from vaginal swabs. Bruce-ladder PCR assay confirmed B. abortus and B. melitensis cultures. The isolation of Brucella spp. was significantly associated with districts, with the Nyagatare district having more isolates than other districts (p = 0.01). This study identified single or mixed B. abortus and B. melitensis infections in cattle samples in Rwanda, which emphasizes the need to improve brucellosis control at the wildlife–livestock–human interface and raise the awareness of cattle keepers, abattoir workers, laboratory personnel, and consumers of cattle products.

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.

Causes of abortion in Iranian sheep flocks and associated risk factors

Abortion is a major issue in sheep husbandry. It can result in significant economic losses and a severe public health risk. This survey assessed the infectious and non-infectious causes of abortion in Iranian sheep flocks and determined the main risk factors. In this cross-sectional survey, causes of abortion were evaluated in 757 sheep flocks, and risk factors were analysed. A checklist containing general animal information for each abortion outbreak evaluated was filled in. Data were analysed using univariate tests and multivariable binary logistic regression analysis. In this sense, parity, gestational age of the aborted fetus, vaccination protocol, mineral supplementation and history of stillbirth showed significant associations with abortion. Infectious agents such as Coxiella burnetti (22.7%), Chlamydia abortus (12.3%) and Brucella melitensis (10.4%) were the most frequently isolated in the investigated flocks, with more than 2% of abortion rates. On the other hand, non-infectious agents such as trauma, pregnancy toxaemia and vitamin E/Se deficiency were involved in those flocks with low abortion rates (less than 10%). Results revealed multiple causes of abortion outbreaks among Iranian sheep flocks, which need careful investigation to identify possible aetiology and risk factors. Further studies are necessary to evaluate if these factors are similar to other countries in the same region.

Pathological study and molecular detection of zoonotic diseases in small ruminants at slaughter houses in Mymensingh, Bangladesh

Background and Aim:

Slaughterhouses act as a significant public health hotspot in developing countries like Bangladesh. The study aimed to investigate small ruminants at slaughterhouses for pathological study and molecular detection of important zoonotic diseases.

Materials and Methods:

A total of 75 goats and 14 sheep were investigated from June 2019 to January 2020 at different slaughterhouses in Mymensingh division, Bangladesh. The targeted diseases were tuberculosis (TB), listeriosis, Q fever, brucellosis, anthrax, toxoplasmosis, hydatidosis, and linguatulosis. The tentative diagnosis was made based on gross and histopathological lesions. Polymerase chain reaction (PCR) was performed to confirm the causal agents of zoonotic diseases using disease-specific primers.

Results:

Grossly, caseous nodule formation in the visceral organs; enlarged and calcifications of mesenteric lymph nodes (MLNs); hydatid cyst formation in the liver were the predominant lesions observed. Histopathologically, granuloma, caseous necrosis, and calcifications admixed with acid-fast bacteria in the MLNs, liver, spleen, and kidney were seen as suggestive of infectivity due to TB. Septic lymphadenitis mixed with rod-shaped bacteria, doughnut granuloma, fibroplasia accompanied by eosinophils and lymphocytic infiltration in MLNs, and portal granuloma were observed in listeriosis, Q fever, linguatulosis, and toxoplasmosis suspected cases, respectively. The PCR amplified Mycobacterium tuberculosis complex (372 bp), Mycobacterium bovis (600 bp), Listeria monocytogenes (517 bp), Toxoplasma gondii (512 bp), and Coxiella burnetii (687 bp) species-specific amplicons. In addition, linguatulosis and hydatidosis were identified in six and three goats, respectively. Brucellosis and anthrax were not detected in any cases. The slaughterhouse samples were also found to harbor the coexistence of different zoonotic pathogens.

Conclusion:

Deadly infectious zoonotic diseases in goats and sheep at slaughterhouses may cause widespread public health risks. As a result, more intensive monitoring and epidemiological surveys are required to successfully prevent and control zoonotic diseases.

Development, validation and field evaluation of an indirect ELISA for the detection of antibodies against Brucella abortus in bulk and individual milk samples in dairy cattle

Brucellosis is an abortigenic and zoonotic disease. In cattle, it is mainly caused by Brucella abortus. The disease is endemic in low- and middle-income countries, being considered a neglected zoonotic disease. In these countries, it is of high importance to develop and validate sensitive, specific and low-cost diagnostic assays for brucellosis. The aim of the present study was the development of an indirect enzyme-linked immune assay (iELISA) to detect anti-B. abortus antibodies in milk samples. We purified the lipopolysaccharide antigen from B. abortus and produced an anti-bovine IgG monoclonal antibody to develop an iELISA (iELISA_INTA). The iELISA_INTA was validated using 1730 bulk milk samples and 1734 individual milk samples. The sampled dairy herds had at least 3 years of consistency at their positive or negative official brucellosis status. Individual milk samples were taken in parallel with serum samples from the cows. The status of the cows was defined by the result of the complement fixation test (CFT) performed with their serum sample. The reproducibility of the assay was evaluated in two laboratories. In addition, we evaluated the performance of the assay in the field, using 4385 bulk milk samples and 968 individual milk samples. The results of the iELISA_INTA were compared with those obtained using the officially accepted brucellosis techniques: iELISA from Canada (iELISA_CFIA) in milk samples, and the buffered plate antigen (BPA) and the CFT in serum samples. At validation, the sensitivity (Se) of the iELISA_INTA in bulk milk samples was 98.61 %, and the specificity (Sp) 98.79 % with a ≥ 10 % of positivity (PP) cutoff. In individual milk samples, the Se was 98.04 %, and the Sp 98.56 % with a ≥ 16 PP cutoff. The chance-corrected agreement kappa value (κ) between the results obtained in the different laboratories was κ = 0.87. In the field evaluation, in bulk milk samples the κ value between the iELISA_INTA and the iELISA_CFIA was κ = 0.86. On individual milk samples, the κ values were: between the iELISA_INTA and the iELISA_CFIA κ = 0.79, between the iELISA_INTA and BPA was κ = 0.85, and between the iELISA_INTA and CFT κ = 0.82. The developed iELISA_INTA showed a very good performance and it could be used as a screening assay for anti-B. abortus antibodies detection in individual milk samples and for epidemiologic surveillance in bulk milk samples.

Assays for Identification and Differentiation of Brucella Species: A Review

Brucellosis is one of the most important and widespread bacterial zoonoses worldwide. Cases are reported annually across the range of known infectious species of the genus Brucella. Globally, Brucella melitensis, primarily hosted by domestic sheep and goats, affects large proportions of livestock herds, and frequently spills over into humans. While some species, such as Brucella abortus, are well controlled in livestock in areas of North America, the Greater Yellowstone Ecosystem supports the species in native wild ungulates with occasional spillover to livestock. Elsewhere in North America, other Brucella species still infect domestic dogs and feral swine, with some associated human cases. Brucella spp. patterns vary across space globally with B. abortus and B. melitensis the most important for livestock control. A myriad of other species within the genus infect a wide range of marine mammals, wildlife, rodents, and even frogs. Infection in humans from these others varies with geography and bacterial species. Control in humans is primarily achieved through livestock vaccination and culling and requires accurate and rapid species confirmation; vaccination is Brucella spp.-specific and typically targets single livestock species for distribution. Traditional bacteriology methods are slow (some media can take up to 21 days for bacterial growth) and often lack the specificity of molecular techniques. Here, we summarize the molecular techniques for confirming and identifying specific Brucella species and provide recommendations for selecting the appropriate methods based on need, sensitivity, and laboratory capabilities/technology. As vaccination/culling approaches are costly and logistically challenging, proper diagnostics and species identification are critical tools for targeting surveillance and control.

Isolation and molecular confirmation of Brucella suis biovar 2 from slaughtered pigs: an unanticipated biovar from domestic pigs in Egypt

Background

Brucella suis is a zoonotic pathogen with a serious impact on public health and the pig industry worldwide. Information regarding B. suis in pigs in Egypt is scarce. This study aimed to investigate the prevalence of B. suis in slaughtered domestic pigs at El-Basatin abattoir in Cairo, Egypt. A total of 1,116 domestic pigs slaughtered in 2020 were sampled for Brucella isolation and identification. Identified Brucella isolates were molecularly confirmed at species, and biovar levels using Bruce ladder PCR and Suis ladder multiplex PCR. Additionally, high-risk practices of 16 abattoir workers (4 veterinarians, 10 butchering and evisceration workers, and 2 scalding workers) were investigated using a pre-piloted structured questionnaire.

Results

Brucella isolates were recovered from 1.3% of examined pigs (n = 14) at consistently low rates (1.1—2.9%) across the year of sampling from February to December 2020. All isolates were confirmed as B. suis biovar (bv) 2. Remarkably, 92.9% (13/14) of isolates showed atypical ability to produce H₂S and hence were considered as B. suis bv2 atypical phenotype. The prevalence was higher in males (1.8%) than in females (0.9). However, this difference was not significant (Odds ratio = 1.9; CI 95% 0.7 – 5.7; P = 0.2). No detectable pathological lesions were associated with B. suis bv2 infection in examined pigs. All strains were isolated from cervical lymph nodes, highlighting a potential oral transmission. High-risk practices were recorded among swine abattoir workers in this study: 75% do not wear gloves or disinfect their knives daily, and 18.8% were willing to work with open wound injuries.

Conclusions

To the best of our knowledge, this is the first isolation of B. suis bv2 in Egypt. Detection of H₂S producing B. suis bv2 atypical phenotype is alarming as it may result in misinterpretation of these isolates as highly human pathogenic B. suis bv1 in Egypt and possibly elsewhere. Further epidemiological tracing studies are crucial for the detection of the origin of this biovar. Including pigs in the national surveillance program of brucellosis, and an education program for swine abattoir workers about occupational risk of B. suis is a need in Egypt.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12917-022-03332-2.

Brucella spp. distribution, hosting ruminants from Greece, applying various molecular identification techniques

Background

Brucellosis still remains an endemic disease for both livestock and human in Greece, influencing the primary sector and national economy in general. Although farm animals and particularly ruminants constitute the natural hosts of the disease, transmission to humans is not uncommon, thus representing a serious occupational disease as well. Under this prism, knowledge concerning Brucella species distribution in ruminants is considered a high priority. There are various molecular methodologies for Brucella detection with however differential discriminant capacity. Hence, the aim of this survey was to achieve nationally Brucella epidemiology baseline genotyping data at species and subtype level, as well as to evaluate the pros and cons of different molecular techniques utilized for detection of Brucella species. Thirty-nine tissue samples from 30 domestic ruminants, which were found positive applying a screening PCR, were tested by four different molecular techniques i.e. sequencing of the 16S rRNA, the BP26 and the OMP31 regions, and the MLVA typing panel 1 assay of minisatellite markers.

Results

Only one haplotype was revealed from the 16S rRNA sequencing analysis, indicating that molecular identification of Brucella bacteria based on this marker might be feasible solely up to genus level. BP26 sequencing analysis and MLVA were in complete agreement detecting both B. melitensis and B. abortus. An interesting exception was observed in 11 samples, of lower quality extracted DNA, in which not all expected MLVA amplicons were produced and identification was based on the remaining ones as well as on BP26. On the contrary OMP31 failed to provide a clear band in any of the examined samples.

Conclusions

The present study reveals the constant circulation of Brucella bacteria in ruminants throughout Greece. Further, according to our results, BP26 gene represents a very good alternative to MLVA minisatellite assay, particularly in lower quality DNA samples.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12917-022-03295-4.

Comparative Review of Brucellosis in Small Domestic Ruminants

Brucella melitensis and Brucella ovis are the primary etiological agents of brucellosis in small domestic ruminants. B. melitensis was first isolated in 1887 by David Bruce in Malta Island from spleens of four soldiers, while B. ovis was originally isolated in Australia and New Zealand in early 1950's from ovine abortion and rams epididymitis. Today, both agents are distributed worldwide: B. melitensis remains endemic and associated with an extensive negative impact on the productivity of flocks in -some regions, and B. ovis is still present in most sheep-raising regions in the world. Despite being species of the same bacterial genus, B. melitensis and B. ovis have extensive differences in their cultural and biochemical characteristics (smooth vs. rough colonial phases, serum and CO2 dependence for in vitro growth, carbohydrate metabolism), host preference (female goat and sheep vs. rams), the outcome of infection (abortion vs. epididymitis), and their zoonotic potential. Some of these differences can be explained at the bacterial genomic level, but the role of the host genome in promoting or preventing interaction with pathogens is largely unknown. Diagnostic techniques and measures to prevent and control brucellosis in small ruminants vary, with B. melitensis having more available tools for detection and prevention than B. ovis. This review summarizes and analyzes current available information on: (1) the similarities and differences between these two etiological agents of brucellosis in small ruminants, (2) the outcomes after their interaction with different preferred hosts and current diagnostic methodologies, (3) the prevention and control measures, and (4) alerting animal producers about the disease and raise awareness in the research community for future innovative activities.

Molecular characterization of zoonotic Brucella species isolated from animal and human samples in Iran

Brucellosis is an endemic infection in Iran and represents a serious health problem in humans and livestock causing important economic losses. The objective of this study was to undertake molecular characterization of Brucella spp. isolated from humans and livestock in several provinces of Iran including by multi-locus sequence typing (MLST), in order to understand the genotypes circulating in Iran and their relationship to genotypes globally. A total of 23 Brucella isolates were isolated from eight milk samples (seven cows, and one camel), human blood samples (seven), bovine lymph nodes (two), and samples from aborted fetuses (three sheep, two cows, and one goat). Phenotypic and molecular identification of Brucella isolates was performed on all isolated bacteria and showed that all were either Brucella melitensis or Brucella abortus. B. melitensis was associated with ovine/caprine and camel samples, most human isolates, and a significant minority of cattle isolates. In contrast B. abortus from livestock was associated only with isolations from bovine samples, as well as a single human sample. These results indicate that both B. melitensis and B. abortus contribute to the human brucellosis burden in Iran. B. melitensis isolates comprised three MLST-9 genotypes, the common and globally distributed ST8, a single representative of ST7, and several additional examples of ST102, a genotype previously only reported in a single isolate from a human brucellosis case believed to be acquired through travel to Iran. B. abortus isolates represented two globally common MLST-9 genotypes (ST1 and ST2), with relationships to biotype and other PCR-based typing methods consistent with previous observations. The results provide the basis for further studies examining the molecular epidemiology of Brucella circulating in Iran and the relationships of local isolates to those present globally.

The Importance of Complementary PCR Analysis in Addition to Serological Testing for the Detection of Transmission Sources of Brucella spp. in Greek Ruminants

The early and accurate diagnosis of brucellosis, a ubiquitous zoonotic infection, is significant in preventing disease transmission. This study aimed to assess the infection rate of Brucella spp. in ruminants and to evaluate the agreement between a serological test and a molecular method for the detection of infected cases. Blood and milk samples of 136 ruminants were analyzed using two laboratory methods: the Rose Bengal plate (RBP) test to detect B. abortus and B. melitensis antibodies and the molecular polymerase chain reaction (PCR) method for the presence of bacterial DNA. The agreement between the methods was assessed using the kappa statistic. Based on the RBP test, there were 12 (8.8%) seropositive animals (10 sheep and 2 cows), while 2 (1.4%) samples were positive on PCR analysis. The positive PCR samples were from seronegative cow samples on RBP testing. There was slight agreement (k = −0.02) between the two methods, which was not statistically significant. Our results indicate that complementary molecular methods are useful to detect the bacteria in infected animals that are seronegative due to an early stage of infection. Therefore, a combination of molecular methods and serological tests can be applied to detect brucellosis in ruminants efficiently.

The Retrospective on Atypical Brucella Species Leads to Novel Definitions

The genus Brucella currently comprises twelve species of facultative intracellular bacteria with variable zoonotic potential. Six of them have been considered as classical, causing brucellosis in terrestrial mammalian hosts, with two species originated from marine mammals. In the past fifteen years, field research as well as improved pathogen detection and typing have allowed the identification of four new species, namely Brucella microti, Brucella inopinata, Brucella papionis, Brucella vulpis, and of numerous strains, isolated from a wide range of hosts, including for the first time cold-blooded animals. While their genome sequences are still highly similar to those of classical strains, some of them are characterized by atypical phenotypes such as higher growth rate, increased resistance to acid stress, motility, and lethality in the murine infection model. In our review, we provide an overview of state-of-the-art knowledge about these novel Brucella sp., with emphasis on their phylogenetic positions in the genus, their metabolic characteristics, acid stress resistance mechanisms, and their behavior in well-established in cellulo and in vivo infection models. Comparison of phylogenetic classification and phenotypical properties between classical and novel Brucella species and strains finally lead us to propose a more adapted terminology, distinguishing between core and non-core, and typical versus atypical brucellae, respectively.

Characterization of Brucella spp. and other abortigenic pathogens from aborted tissues of cattle and goats in Rwanda

Background

Abortions cause tremendous economic losses in food‐producing animals and may lead to food insecurity.

Objectives

This study aimed to characterize Brucella spp. and other abortigenic pathogens from aborted tissues of cattle.

Methods

For cattle, aborted tissues (n = 19) were cultured, and Brucella spp. were detected using the genus‐specific 16S‐23S ribosomal DNA interspacer region (ITS) assay and speciated using Brucella abortus, Brucella melitensis, Brucella ovis, and Brucella suis (AMOS) and Bruce‐ladder PCR assays. Brucella negative samples were screened using the eight abortigenic pathogens PCR panel. Samples from an abortion outbreak that occurred within a goat tribe were included in this investigation. Sera of females (n = 8) and males (n = 2) were analyzed using the Rose Bengal Test (RBT) and indirect enzyme‐linked immunosorbent assay (i‐ELISA), while vaginal swabs (n = 3) and aborted tissues (n = 1) were cultured and characterized.

Results

The ITS‐PCR detected Brucella DNA in cultures from two aborted tissues of cattle (10.5%, [2/19]), which were identified as B. melitensis (n = 1), and B. abortus (n = 1) using AMOS and Bruce‐ladder PCR assays. Campylobacter fetus (n = 7) and Leptospira spp. (n = 4) including co‐infections (n = 2) of C. fetus and Leptospira spp. were identified from the Brucella negative samples of cattle. Goats (100.0%, 10/10) were brucellosis seropositive on RBT and i‐ELISA. Mixed infections caused by B. melitensis and B. abortus were isolated from the vaginal swabs (n = 3) and aborted tissues (n = 1).

Discussion and conclusions

This is the first identification of abortion‐associated pathogens in aborted cattle indicating the enormous financial losses and a threat to public health. It is therefore essential to include these identified pathogens in the surveillance scheme of veterinary and human services.

Molecular detection of Brucella abortus in wild and captive felids

Purpose

Brucellosis is a zoonotic disease of great public health importance. In wild animals, Brucella abortus is one of the most diagnosed species, mainly in enzootic environments where domestic animals share the same environment. B. abortus is common in environments shared by cattle, wild, and domestic animals. This study aimed to detect the presence of B. abortus DNA in free-ranging and captivity felids at Mato Grosso State, Brazil.

Method

Polymerase chain reaction, based on the genetic element IS711, was performed in blood samples collected from 23 free-ranging and captive felids. The species represented include Leopardus colocolo, Leopardus pardalis, Leopardus wiedii, Panthera onca, Puma concolor, and Puma yagouaroundi.

Results

DNA amplification of B. abortus was observed in only one captive P. concolor (4.34%).

Conclusion

The detection of this pathogen in captive animals using molecular tools demonstrates the importance of monitoring, as it raises concerns about the possibility of transmission between humans and wild and domestic animals, especially in regions of vast biodiversity, such as in the State of Mato Grosso, Brazil.

Brucella ceti sequence type 23, 26, and 27 infections in North American cetaceans

Brucella ceti infection is associated with a variety of disease outcomes in cetaceans globally. Multiple genotypes of B. ceti have been identified. This retrospective aimed to determine if specific lesions were associated with different B. ceti DNA sequence types (STs). Characterization of ST was performed on 163 samples from 88 free-ranging cetaceans, including common bottlenose dolphin Tursiops truncatus (T.t.; n = 73), common short-beaked dolphin Delphinus delphis (D.d.; n = 7), striped dolphin Stenella coeruleoalba (n = 3), Pacific white-sided dolphin Lagenorhynchus obliquidens (n = 2), sperm whale Physeter macrocephalus (n = 2), and harbour porpoise Phocoena phocoena (n = 1), that stranded along the coast of the US mainland and Hawaii. ST was determined using a previously described insertion sequence 711 quantitative PCR. Concordance with 9-locus multi-locus sequence typing was assessed in a subset of samples (n = 18). ST 26 was most commonly identified in adult dolphins along the US east coast with non-suppurative meningoencephalitis (p = 0.009). Animals infected with ST 27 were predominately perinates that were aborted or died shortly after birth with evidence of in utero pneumonia (p = 0.035). Reproductive tract inflammation and meningoencephalitis were also observed in adult T.t. and D.d. with ST 27, though low sample size limited interpretation. ST 23 infections can cause disease in cetacean families other than porpoises (Phocoenidae), including neurobrucellosis in D.d. In total, 11 animals were potentially infected with multiple STs. These data indicate differences in pathogenesis among B. ceti STs in free-ranging cetaceans, and infection with multiple STs is possible.

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.

The Use of Flocked Swabs with a Protective Medium Increases the Recovery of Live Brucella spp. and DNA Detection

Brucellosis is a worldwide zoonosis caused by bacteria from the genus Brucella. Once established, it is very hard to eradicate this disease, since it contaminates animals, the environment, and humans, causing problems for veterinary and public health as well as wildlife protection programs. Swabs are used for sampling in bacteriological and/or molecular diagnostics, from seropositive animals with disease symptoms, from genitalia or tissue lesions, as well as from contaminated environments. The aim of this study was to compare main of the commercially used swab types for sampling and diagnostics of Brucella spp. and determine the optimal storage conditions and time frame for testing. To achieve this, we tested bacterial and molecular methods for detection of Brucella abortus, Brucella melitensis, and Brucella suis using nine swab types, all with different tip materials, treated immediately after spiking, after 72 h at +4°C, and after 72 h at −20°C. Flocked swabs showed the highest capacity to preserve bacterial viability and DNA quality, regardless the storage conditions. Flocked swabs immersed in a protective medium provided the best conditions for Brucella survival in all three storage conditions. At the same time, the efficacy of quantitative PCR (qPCR) detection for all swabs, including the positive control, was above 50%, irrespective of the storage conditions, while bacterial survival was significantly lowered when swabs were kept at +4°C or −20°C for 72 h (48.2% and 27.5%, respectively). Compared to the positive control and other types, the flocked swabs maintained higher reproducibility regarding their capacity to preserve live bacteria in all three storage conditions.

IMPORTANCE In order to protect public and veterinary health from highly zoonotic bacteria such as members of the genus Brucella and prevent their dissemination into the environment, direct diagnostics are of utmost importance. However, in addition to the highly specific diagnostic tests, the sampling methods, time necessary for specimens to reach the laboratories, and transport conditions are important factors to consider in order to increase the sensitivity of performed tests, especially bacterial culturing and qPCR. This paper shows how different swab types and storage conditions influence classical bacteriological diagnostics of the most prevalent Brucella species – B. melitensis, B. abortus, and B. suis – but have little impact on molecular methods. The presented results highlight (i) the choice of swab regarding the storage and transport conditions, (ii) the importance of immediate swab treatment upon sampling, and (iii) that molecular methods do not depend on storage conditions, unlike classical bacteriological isolation.

Vaccination with a Brucella ghost developed through a double inactivation strategy provides protection in Guinea pigs and cattle

Vaccination can prevent and control animal brucellosis. Currently, live attenuated vaccines are extensively used to prevent Brucella infection. However, traditional vaccines such as live attenuated vaccines are associated with biological safety risks for both humans and animals. The bacterial ghost (BG) is a new form of vaccine with great prospects. However, bacterial cells cannot be completely inactivated by biological lysis, conferring a safety risk associated with the vaccine. In this study, we developed a Brucella abortus A19 bacterial ghost (A19BG) through a double inactivation strategy with sequential biological lysis and hydrogen peroxide treatment. This strategy resulted in 100% inactivation of Brucella, such that viable bacterial cells were not detected even at an ultrahigh concentration of 10¹⁰ colony-forming units/mL. Furthermore, A19BG had a typical BG morphology and good genetic stability. Moreover, it did not induce adverse reactions in guinea pigs. The levels of antibodies, interferon-γ, interleukin-4, and CD4⁺ T cells in guinea pigs inoculated with the A19BG vaccine were similar to those inoculated with the existing A19 vaccine. Immunization with A19BG conferred a similar level of protection with that of A19 against Brucella melitensis M28 in both guinea pigs and cattle. In conclusion, the combination of biological lysis and H₂O₂-mediated inactivation is a safe and effective strategy that can serve as a reference for the preparation of BG vaccines.

Surface plasmon resonance aptasensor for Brucella detection in milk

A Surface Plasmon Resonance (SPR) aptasensor was developed for the detection of Brucella melitensis (B. melitensis) in milk samples. Brucellosis is a bacterial zoonotic disease with global distribution caused mostly by contaminated milk or their products. Aptamers recognizing B. melitensis were selected following a whole bacteria-SELEX procedure. Two aptamers were chosen for high affinity and high specificity. The high affinity aptamer (B70 aptamer) was immobilized on the surface of magnetic silica core-shell nanoparticles for initial purification of the target bacteria cells from milk matrix. Another aptamer, highly specific for B. melitensis cells (B46 aptamer), was used to prepare SPR sensor chips for sensitive determination of Brucella in eluted samples from magnetic purification since direct injection of milk samples to SPR sensor chips is known for a high background unspecific signal. Thus, we integrated a quick and efficient magnetic isolation step for subsequent instant detection of B. melitensis contamination in one ml of milk sample by SPR with a LOD value as low as 27 ± 11 cells.

Diagnostic Findings in a Confirmed Outbreak of Brucella ovis Infection in a Traditional Sheep Farm in Sicily (South-Italy)

Aim of this study is to report a laboratory investigation performed following the isolation of Brucella ovis, causing ovine epididymitis, in a traditional sheep farm in Sicily (South Italy). This disease represents a newly emerging risk for Italian livestock and is listed among diseases of EU priority (EU Reg 2016/429). Blood samples from 56 rams and 143 ewes were analyzed by both Enzyme-Linked Immunosorbent Assay (ELISA) and Complement Fixation Test (CFT). Genital swabs from all rams and 15 lactating ewes were collected to perform real-time PCR. Eighteen serologically positive rams were slaughtered and postmortem-inspected. Samples of testicle, epididymis, lymph nodes, and urine were also collected in order to perform microbiological, molecular, and histopathological analysis. Twelve slaughtered rams showed anatomo-pathological lesions. Real-time PCR for B. ovis BOV_A0504 gene was positive for 13 testicles and epididymis and 11 urine while B. ovis was isolated from epididymis and testicles of 7 slaughtered rams. This is the first exhaustive laboratory report of a microbiological, molecular, and serological pattern of the disease in sheep in Italy. Despite the impact on health and animal welfare, the epidemiology of B. ovis infection is still unknown, particularly in our country where the disease is considered endemic.

Seroprevalence trend of human brucellosis and MLVA genotyping characteristics of Brucella melitensis in Shaanxi Province, China, during 2008-2020

In this study, a total of 179,907 blood samples from populations with suspected Brucella spp. infections were collected between 2008 and 2020 and analyzed by the Rose Bengal plate test (RBPT) and serum agglutination test (SAT). Moreover, conventional biotyping, B. abortus-melitensis-ovis-suis polymerase chain reaction (AMOS-PCR), and multiple-locus variable-number tandem repeat analysis (MLVA) was applied to characterize the isolated strains. A total of 8103 (4.50%) samples were positive in RBPT, while 7705 (4.28%, 95% confidence interval (CI) 4.19-4.37) samples were positive in SAT. There was a significant difference in seroprevalence for human brucellosis over time, in different areas and different cities (districts) (χ² = 2 = 32.23, 1984.14, and 3749.51, p < .05). The highest seropositivity (8.22% (4, 965/60393; 95% CI 8.00-8.44) was observed in Yulin City, which borders Inner Mongolia, Ningxia, and Gansu Province, China, regions that have a high incidence of human brucellosis. Moreover, 174 Brucella strains were obtained, including nine with B. melitensis bv. 1, 145 with B. melitensis bv. 3, and 20 with B. melitensis variants. After random selection, 132 B. melitensis were further genotyped using MLVA-16. The 132 strains were sorted into 100 MLVA-16 genotypes (GTs) (GT 1-100), 81 of which were single GTs represented by singular independent strains. The remaining 19 shared GTs involved 51 strains, and each GT included two to seven isolates from the Shaan northern and Guanzhong areas. These data indicated that although sporadic cases were a dominant epidemic characteristic of human brucellosis in this province, more than 38.6% (51/132) outbreaks were also found in the Shaan northern area and Guanzhong areas. The 47 shared MLVA-16 GTs were observed in strains (n = 71) from this study and strains (n = 337) from 19 other provinces of China. These data suggest that strains from the northern provinces are a potential source of human brucellosis cases in Shaanxi Province. It is urgent to strengthen the surveillance and control of the trade and transfer of infected sheep among regions.

Genome Sequencing and Comparative Genomics of Indian Isolates of Brucella melitensis

Brucella melitensis causes small ruminant brucellosis and a zoonotic pathogen prevalent worldwide. Whole genome phylogeny of all available B. melitensis genomes (n = 355) revealed that all Indian isolates (n = 16) clustered in the East Mediterranean lineage except the ADMAS-GI strain. Pangenome analysis indicated the presence of limited accessory genomes with few clades showing specific gene presence/absence pattern. A total of 43 virulence genes were predicted in all the Indian strains of B. melitensis except 2007BM-1 (ricA and wbkA are absent). Multilocus sequence typing (MLST) analysis indicated all except one Indian strain (ADMAS-GI) falling into sequence type (ST 8). In comparison with MLST, core genome phylogeny indicated two major clusters (>70% bootstrap support values) among Indian strains. Clusters with <70% bootstrap support values represent strains with diverse evolutionary origins present among animal and human hosts. Genetic relatedness among animal (sheep and goats) and human strains with 100% bootstrap values shows its zoonotic transfer potentiality. SNP-based analysis indicated similar clustering to that of core genome phylogeny. Among the Indian strains, the highest number of unique SNPs (112 SNPs) were shared by a node that involved three strains from Tamil Nadu. The node SNPs involved several peptidase genes like U32, M16 inactive domain protein, clp protease family protein, and M23 family protein and mostly represented non-synonymous (NS) substitutions. Vaccination has been followed in several parts of the world to prevent small ruminant brucellosis but not in India. Comparison of Indian strains with vaccine strains showed that M5 is genetically closer to most of the Indian strains than Rev.1 strain. The presence of most of the virulence genes among all Indian strains and conserved core genome compositions suggest the use of any circulating strain/genotypes for the development of a vaccine candidate for small ruminant brucellosis in India.

Circulating Brucella species in wild animals of the Serengeti ecosystem, Tanzania

BACKGROUND

Brucellosis is a bacterial zoonosis of public health and economic importance worldwide. It affects a number of domestic animals, wild animals and humans. Human brucellosis originates from either livestock or wildlife. The species of Brucella circulating in wild animals in Tanzania is largely unknown due to insufficient surveillance. This study was carried out to identify Brucella species found in selected wildlife hosts in the Serengeti ecosystem.

METHODOLOGY

The study used a total of 189 archived samples that were obtained from cross-sectional studies previously conducted between 2000 and 2017 in the Serengeti ecosystem in Tanzania. Whole blood, serum and amniotic fluid collected from buffalos, lions, wildebeest, impala, zebra and hyena were available for DNA extraction. Multiplex polymerase chain reaction for B. abortus, B. melitensis, B. ovis and B. suis (AMOS PCR) and quantitative real-time PCR (qPCR) targeting the bcsp31 and IS711 genes for Brucella genus detection and the IS711 targets alkB for B. abortus and BMEI1162 for B. melitensis were used to detect Brucella strains.

RESULTS

Out of the 189 samples tested, 12 (6.35 %) and 22 (11.6 %) were positive to AMOS-PCR and qPCR, respectively. Most of the positive samples were from lions (52.6 %) and buffaloes (19.6 %). Other animals that were positive included: wildebeest (13.6 %), impala (13.6 %), zebra (4.5 %) and hyena (4.5 %). Out of 22 positive samples, 16 (66.7 %) were identified as B. abortus and the other six samples did not amplify for neither B. abortus nor B. melitensis.

CONCLUSIONS

The detection of Brucella DNA in archived wild animal samples shows testing potential of samples collected from this population. The zoonotic species B. abortus and B. melitensis detected in wild animals have previously been reported in livestock and humans in the region. The findings suggest that, due to the contact network, some of the identified wild animal hosts in this study could be reservoirs for infections in domestic animals and humans within the Serengeti ecosystem while others are likely dead-end hosts. One Health control strategies and continuous surveillance programs in other wildlife reserved areas should be implemented to help predicting transmission in livestock and humans in the region.

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.

The one hundred year journey of the genus Brucella (Meyer and Shaw 1920)

The genus Brucella, described by Meyer and Shaw in 1920, comprises bacterial pathogens of veterinary and public health relevance. For 36 years, the genus came to include three species that caused brucellosis in livestock and humans. In the second half of the 20th century, bacteriologists discovered five new species and several 'atypical' strains in domestic animals and wildlife. In 1990, the Brucella species were recognized as part of the Class Alphaproteobacteria, clustering with pathogens and endosymbionts of animals and plants such as Bartonella, Agrobacterium and Ochrobactrum; all bacteria that live in close association with eukaryotic cells. Comparisons with Alphaproteobacteria contributed to identify virulence factors and to establish evolutionary relationships. Brucella members have two circular chromosomes, are devoid of plasmids, and display close genetic relatedness. A proposal, asserting that all brucellae belong to a single species with several subspecies debated for over 70 years, was ultimately rejected in 2006 by the subcommittee of taxonomy, based on scientific, practical, and biosafety considerations. Following this, the nomenclature of having multiples Brucella species prevailed and defined according to their molecular characteristics, host preference, and virulence. The 100-year history of the genus corresponds to the chronicle of scientific efforts and the struggle for understanding brucellosis.