Brucellosis Surveillance Research Articles

Performance of an Immunochromatographic Test (ICT) in Comparison to Some Commonly Used Serological Tests for the Diagnosis of Brucellosis in Dromedary Camels (Camelus dromedarius).

Serological tests may represent an essential tool for the diagnosis of camel brucellosis; however, concerns arise in the scientific community regarding the direct transposition from cattle and small ruminants without adequate validation. The present study was made to compare four serological tests for the diagnosis of brucellosis in dromedary camels (Camelus dromedarius). In terms of sensitivity, our results show that the Immunochromatographic Test (ICT) shows the higher value of sensitivity, 98.67% (95% Confidence Level (C.L): 94.36–99.99%), followed by the Fluorescence Polarization Assay (FPA) with 95.05% (95% C.L: 88.23–99.51%), then the Competitive Enzyme-Linked Immunosorbent Assay (c-ELISA) with 94.94% (95% C.L: 88.25–99.45%) and, finally, the Rose Bengal Test (RBT) with 68.95% (95% C.L: 56.55–80.69%), which is the only test showing a significantly lower sensitivity compared to the others. On the other hand, our study revealed no significant difference in terms of specificity between all the tests under study, with a range from 99.06% (95% C.L: 98.34–99.64%) for the ICT to 99.92% (95% C.L: 99.64–100%) for the RBT. The ICT was found to be comparable in terms of sensitivity and specificity with the most commonly used tests for camel brucellosis. The results of the present study are of paramount importance for designing surveillance and control measures for brucellosis in camel populations.

A comparison of three data mining time series models in prediction of monthly brucellosis surveillance data.

The early and accurately detection of brucellosis incidence change is of great importance for implementing brucellosis prevention strategic health planning. The present study investigated and compared the performance of the three data mining techniques, random forest (RF), support vector machine (SVM) and multivariate adaptive regression splines (MARSs), in time series modelling and predicting of monthly brucellosis data from 2005 (March/April) to 2017 (February/March) extracted from a national public health surveillance system in Hamadan located in west of Iran. The performances were compared based on the root mean square errors, mean absolute errors, determination coefficient (R2 ) and intraclass correlation coefficient criteria. Results indicated that the RF model outperformed the SVM and MARS models in modeling used data and it can be utilized successfully utilized to diagnose the behaviour of brucellosis over time. Further research with application of such novel time series models in practice provides the most appropriate method in the control and prevention of future outbreaks for the epidemiologist.

Progress in research and practice of brucellosis surveillance in China

In recent years, the reported incidence of brucellosis continued to rise and the epidemic spread kept, which has become an important public health problem in China. Continuous improvement of the surveillance system is important for effective control and prevention of brucellosis. This article systematically summarizes the construction and development of the brucellosis surveillance system, analyzes the main characteristics of the current brucellosis surveillance system and evaluates the surveillance system in China, and it also put forward suggestions for the further improvement of the surveillance system to meet the new requirement for brucellosis surveillance, control and prevention.

Evaluation of the Indonesian Animal Brucellosis Surveillance System in 2016 using the Outild’analyse des systèmes de surveillance (OASIS) Method

Surveillance system evaluation is essential for the system improvement. The Indonesia government is conducting the animal brucellosis surveillance to determine herd prevalence and detect infected animals in the herd. This study was conducted to evaluate this brucellosis surveillance system using the Outild’analyse des systèmes de surveillance (OASIS) tool. The questionnaire, developed based on the OASIS tool, was sent to officers in charge of the surveillance system at national, regional and local levels. After collection of information, a consensus panel meeting was conducted to validate and summarize the responses. The OASIS tool assessed the level of satisfaction, critical points and attributes of the surveillance system. There were 37 respondents, including 27 provincial, eight regional and two national officers. The respondents were most satisfied with the information dissemination component of the system. They were also satisfied with the utility of the system, laboratory capacity, surveillance tool, data analysis and communication. In contrast, attention was needed for field institutional organization, surveillance procedures and evaluation, sampling points, and representativeness. Corrective actions can be taken and prioritized based on the evaluation findings, focusing at specific elements which did not meet the officers’ expectation.

Spinal brucellosis in Hulunbuir, China, 2011-2016.

Purpose: To investigate the demographic, epidemiological, clinical, and laboratory characteristics; treatment options; and outcome of human brucellosis with spine involvement at a major hospital in Hulunbuir, a brucellosis epidemic region of China.Patients and methods: A total of 842 patients with human brucellosis treated in the Department of Brucellosis, Hulunbuir People’s Hospital from January 2011 to December 2016 were included and analyzed in this study. The results of 67 brucellar spondylodiscitis (BS) cases were compared with those that were negative for spine involvements.Results: The mean age of spinal brucellosis patients was 50.5±10.2 years (43 males and 24 females; age range 29–70). The risk factors for transmission are direct contact with animals, such as working in the farm, and consumption of unpasteurized milk or daily products. Back pain (92.5%), fever (85.1%), sweating (62.7%), and fatigue (52.8%) were the most common symptoms. Magnetic resonance imaging (MRI) was performed in all the patients with spondylodiscitis. The sites of involvement were lumbar (81.2%), thoracic (8.7%), cervical (4.3%), thoracolumbar (2.9%), and lumbosacral (2.9%). All isolates from blood culture were identified as Brucella melitensis, with 61% biovar 3 and 39% biovar 1 isolates. The antimicrobial therapy for BS lasted for at least 3 months. In the presence of paravertebral or epidural abscess, longer treatment was conducted to avoid possible sequelae.Conclusion: In endemic areas such as Hulunbuir, BS should be considered in patients with back pain and fever. MRI is a highly sensitive imaging modality that can be used to differentiate BS from other spinal infections. This study will be helpful to establish strategies for prevention, surveillance, and management of spinal brucellosis in China.

An Evaluation of the National Brucellosis Surveillance System in Qatar, 2018.

IntroductionBrucellosis is one of the most prevalent bacterial zoonoses and is considered an economically important infection that affects humans and livestock. The infection is usually transmitted to humans through direct contact with infected materials, such as the afterbirth, or indirectly through the ingestion of animal products. In addition, the consumption of raw milk represents a major source of the infection. In the Eastern Mediterranean region, the incidence of brucellosis ranges from one per 100,000 to 20 per 100,000; however, the actual figure is estimated at 20 to 25 times greater owing to the poor surveillance systems among countries in the region. For such reasons, this study is conducted to comprehensively evaluate the brucellosis surveillance system in Qatar, to identify potential strengths and limitations and, hence, inform decision-makers about future mitigation strategies.MethodsA retrospective record review was conducted at the surveillance unit in the Ministry of Public Health (MoPH) to analyze all Brucella notification forms from January to November 2018 for the completeness of notification and timeliness of reporting. The principal investigators conducted data abstraction and analysis in November 2018.ResultsA total of 125 notification forms were analyzed. It was revealed that the internal completeness varied across the different data elements of the notification forms from 39% up to 100%. Also, the timeliness of the reporting ranged from one day for the T3 time point up to 16 days for the T1 time point.ConclusionUltimately, the strengthening of the national Brucellosis surveillance system in Qatar demands the implementation of several strategies, including the establishment of veterinary surveillance, enforcement of livestock importation protocols, as well as routine compulsory vaccinations, devising a clear and sensitive case definition of the disease, and public education especially among high-risk groups (shepherds, slaughterhouse workers, and laboratory workers). In addition, continuous education of healthcare workers on the proper reporting of the disease and the electronization of the notification process are important steps to improve the surveillance system in the country.

The impact of expanded brucellosis surveillance in beef cattle on human brucellosis in Korea: an interrupted time-series analysis

BackgroundKorean surveillance program for bovine brucellosis was improved by extending it to beef slaughterhouses and by pre-movement testing of bulls on May 2005 (Intervention 1). The bovine brucellosis surveillance program was further extended to beef cattle farms with more than 10 heads of cattle on June 2006 (Intervention 2).MethodsTo quantify the temporal relationship between bovine and human brucellosis, a time-series analysis was conducted using Korean national notification data reported between January 2004 and December 2014.ResultsOur findings indicate that while during the pre-intervention phase (January 2004 to March 2005) there was no significant temporal relationship between the incidences of bovine and human brucellosis, significant temporal relationships were observed after Intervention 1 (June 2005 to June 2006, no lag, β = 0.57, p = 0.04), and Intervention 2 (July 2006 to June 2007, 1-month lag, β = 0.65, p = 0.03). Furthermore, significant changes in incidence in human were observed after Intervention 1 (β = − 0.17 per 10 million-people, p = 0.03) and Intervention 2 (β = − 0.19 per 10 million-people, p = 0.04).ConclusionsThese findings indicated the changes of a nationwide comprehensive surveillance programme targeting all cattle is required for effective reduction in the human population.

Epidemiological and Zoonotic Surveillance of Brucellosis in Beni-Suef Governorate

Epidemiological and Zoonotic Surveillance of Brucellosis in Beni-Suef Governorate

Review of bovine brucellosis surveillance in Europe in 2015.

Bovine brucellosis is a major zoonosis and is responsible for significant reproductive disorders and production losses in cattle. Surveillance and control are regulated at the European level with specific conditions to obtain and maintain the officially free status, which facilitates access to export markets. These European standards allow for harmonisation in brucellosis surveillance and diagnosis while leaving some flexibility to countries in the choice of measures to meet the desired objectives. This study reviews the bovine brucellosis surveillancesystems currently in place across the European continent, according to countries' brucellosis status, based on a survey addressed to brucellosis diagnosis expertsin the National Reference Laboratory of each country. Experts were asked toprovide synthesised surveillance data and to describe technical conditions andscreening tests carried out for the surveillance of abortions, serological testing inherds, movement controls and any other surveillance components in 2015. Results were obtained for 34 out of 37 countries (92%). Surveillance systems included abortion surveillance (34 countries), routine herd screening (28 countries), movement testing (14 countries), routine testing at bull stations (9 countries),and screening tests at slaughterhouses (4 countries). The review highlighted variability in technical conditions and screening tests among countries. These results are discussed with regard to the European Union regulations, disease risks and epidemiological situations, with the aim of improving surveillance efficacy and efficiency.

Knowledge, Attitudes and Practices Associated with Brucellosis among Small-Scale Goat Farmers in Thailand

ABSTRACTObjectives: This study aimed to identify occupational risk factors for brucellosis among small scale goat farmers in Thailand.Methods: To better understand farmers’ knowledge, attitudes and practices associated with brucellosis we interviewed 51 farmers and tested 314 goats for Brucella melitensis.Results: All serological samples tested negative for Brucella infection. Based on previous research and estimates provided from the Thai national brucellosis surveillance system, zero seropositivity was less than expected. Findings from interviews with farmers demonstrate that most respondents were relatively new to goat farming with just over half (53%) reporting owning goats for five or fewer years. The majority of respondents demonstrated important gaps in knowledge on disease transmission in animals and knowledge of human brucellosis was particularly limited with just over half (54%) reporting that humans could become infected. Participants had a very low perceived risk of infection with the majority (91.7%) reporting that they or a member of their household were not at risk of the disease.Conclusion: Overall findings from this study support that brucellosis poses an occupational risk to goat farmers with specific areas of concern including weak awareness of disease transmission to humans and lack of knowledge on specific safe farm practices such as quarantine practices. Findings from this study contribute to a more comprehensive understanding of brucellosis in Thailand by identifying specific occupational risk factors and describing areas where farmer education and training should be strengthened.

SEROPREVALENCE OF EQUINE BRUCELLOSIS: FIRST REPORT IN BANGLADESH

Despite the endemicity of brucellosis, there is no report on the equine brucellosis in Bangladesh. The Rose Bengal Test (RBT) was used to determine the seroprevalence of Brucella antibodies amongst 112 horses from different areas of Bangladesh. The overall seroprevalence of equine brucellosis was 1.79%.The prevalence recorded in Ghatail area was 3.45% and there was no positive reactor in Shakipur and Savar areas. Sex wise prevalence showed that the prevalence was 3.08%in female and 0.00% in male horse. Only the adult (>3 years of old) horses showed the positive RBT reaction (2.35%), whereas young (<3 years of old) horses did not showed positive RBT reaction. The present study reports the first serological prevalence of Brucella infection in horses in Bangladesh. There is need for the inclusion of horses in brucellosis surveillance and control strategies in Bangladesh to safeguard people from high risk.

Brucellosis Prevalence in Brazilian Slaughterhouses with Different Meat Inspection Systems

In Brazil, meat inspection occurs in a decentralized manner and consists of three types: (i) federal inspection (SIF), (ii) state inspection (SISP), and (iii) municipal inspection (SIM). The objective of this work was to discuss the three current inspection systems through the apparent prevalence of bovine brucellosis, a zoonosis that has an eradication program implemented by the Brazilian government. Nine abattoirs from federal, state, and municipal inspection systems were assessed and 1,490 animals were sampled. Serology for brucellosis was determined by the rose bengal test and the complement fixation test. The overall apparent prevalence (and 95% confidence interval) of brucellosis was 2.2% (1.5 to 2.9%). Apparent prevalence stratified by inspection system for SIF, SISP, and SIM was 0.4% (0.0 to 0.9%), 2.0% (0.8 to 3.2%), and 4.3% (2.5 to 6.1%), respectively. Multivariable logistic regression analysis revealed the odds ratio for finding an animal positive for brucellosis among inspection systems. A statistical difference ( P < 0.0015) was observed among surveillance systems, with SISP × SIF, SIM × SISP, and SIM × SIF having an odds ratio of 4,996, 2,304, and 11,494, respectively. Hence, the need for increasing official surveillance in state and municipal inspection systems seems to be necessary and could assist in the surveillance of bovine brucellosis and other diseases of interest to the federation. In addition, an increase in official presence would help to improve the selection of slaughtered cattle during ante- and postmortem inspection, with consequent impact on food safety and public health.

Evaluating the burden of brucellosis in hospitalized patients in Armenia, 2016

ObjectiveTo understand the disease burden, we studied the epidemiological and clinical characteristics and associated costs for brucellosis patients hospitalized in Nork hospital in 2016.IntroductionBrucellosis, endemic in Armenia, is recognized as a significant public health challenge with a major economic burden. To address the regional threat of brucellosis for both animal health and public health, the “One Health Surveillance of Brucellosis in Armenia” was initiated in December 2016. The project aims to develop scientifically sound strategies and policies for sustainable control of the disease.MethodsIn 2016, 265 patients diagnosed with brucellosis were hospitalized at “Nork” hospital, of whom 16 were 0-14 years old and 94% were males. Diagnosis was confirmed using agglutination test and ELISA. The SPSS program was used to analyze the data.ResultsDistribution of the disease by marz revealed that the most cases came from Ararat (53), followed by Kotayk (49), Armavir (38), Aragatsotn (36), Yerevan (28), Gegharkunik (26), Vayots Dzor (24), Syunik (8), and Lori (3). Clinical data indicated that 71% of patients had acute brucellosis with fever, arthralgia and night sweating while 29% suffered chronic brucellosis with damage of organ systems. The primary complaints included arthralgia (80%), sweating (60%) and fever (40%). Joint pain was mainly located in knee, elbow, and sacroiliac regions. Average grade of fever was 37,9±0,95oC. Total days spent in hospital were 1798, economic losses for the hospital were estimated at AMD 36 million per year.ConclusionsThose at the highest risk for brucellosis were males living in Ararat and Kotayk marzes who work with livestock.

Estimating the prevalence of Brucellosis in cattle in Zimbabwe from samples submitted to the Central Veterinary Laboratory between 2010 and 2014.

Brucellosis is a disease caused by bacteria belonging to the genus Brucella, which is endemic in sub-Saharan African countries, including Zimbabwe. Zimbabwe has a widespread dairy industry with peri-urban dairy establishments built in order to improve milk availability to rural communities. This study has been the first attempt to estimate the prevalence of brucellosis in Zimbabwe as a whole, using samples submitted to the Central veterinary laboratory between 2010 and 2014. A total of 156 farms were tested with Rose Bengal Test (RBT), Complement Fixation Test (CFT) and Milk Ring Test (MRT). Parallel testing was used to determine whether or not a farm was to be considered positive: 30.1% (95% C.I.: 23.5% - 37.8%) of the farms tested were found positive (47/156). Harare district had the highest number of sample submissions with 6 out of 17 farms testing positive (P = 37.5%; 95% C.I.: 18.4% - 61.7%). Awareness of milk-borne zoonoses is reportedly generally low in farmers (41.5%). This is even more the case in small-holder farmers who have higher likelihoods of selling or ingesting raw milk compared with dairy farmers. The results show the need to carry out surveillance of brucellosis in cattle in Zimbabwe to understand the spatial distribution of the disease in the country. This is particularly relevant given the zoonotic and economic implications of this disease.

Evaluation of Automated Online Quality Checker Implementation for the Brucellosis Surveillance system, Egypt 2016

Background: National Egyptian Disease Surveillance System collects data on 40 diseases and conditions from 584 nominated reporting sites out of 27 governorates. Brucellosis is a weekly notifiable disease. Reporting levels of completeness and timeliness may differ that may influence data quality; these attributes needed to be assessed prior further manipulation of data. In 2016, Surveillance Online Checker (SOC) was launched to facilitate quality check to give feedback about timeliness and completeness of optional (to online entry) variables to the reporting sites (Completeness of mandatory variables is 100%). Objective: We aimed to measure the effect of Surveillance Online Checker on brucellosis surveillance data completeness and timeliness after one year of implementation. Methods: Brucellosis data completeness and timeliness of selected optional variables from the case reporting form were compared before and after one year (2015-2016) of launching SOC using Chi square and student t-test. Results: It is found that completeness of optional variables were increased from 67.3 % to 78.4% as follows; Detailed Address (67.3% to 78.9%, P<0.0001), Patient Telephone (22.1% to 59.9%, P<0.0001), National ID (2.8% to 23.8%, P<0.0001), Lab Test (81.3% to 86.2%, P=0.043) Final Diagnosis (68.3 to 91.8, P<0.0001) and Investigation Forms (52.3% to 75.2%, P<0.0001). While other variables had no significant change such as Occupation (92.7% to 93.0%, P=0.946). The reporting during predefined Timeliness increased from 69.1% to 89.8%, P<0.0001, with Average Data Entry Time per Case since its classification improved to be 3.8 days instead of 8.8 days. The average time to retrieve previous calculations shortened from 2 working days /month to just seconds after running SOC. Conclusions: Completeness and timeliness of brucellosis surveillance improved after SOC. It is recommended to utilize SOC results by intermediate and peripheral levels after adapting SOC for these levels and adding additional surveillance attributes to SOC.

Novel diagnostic approach on the identification of Brucella melitensis Greek endemic strains‐discrimination from the vaccine strain Rev.1 by PCR‐RFLP assay

Despite the intensive implementation of control programmes goat, sheep and human brucellosis remains endemic in Greece. As the discrimination between field endemic strains and vaccine strain Rev.1 is not feasible, it is essential to develop new diagnostic tools for brucellosis diagnosis. Moreover, effective disease control requires enhanced epidemiological surveillance in both humans and animals including robust laboratory support. Two new multiplex (duplex) polymerase chain reactions (PCRs) were developed and the results were compared with those obtained by real‐time PCR and bacteriological biotyping. A total of 71 Brucella spp. Greek endemic strains were identified at species and biovar level, using both molecular and conventional techniques. Their discrimination from the vaccine strain Rev.1 was achieved, using polymerase chain reaction‐restriction fragment length polymorphism assay (PCR‐RFLP). All 71 strains were identified as Brucella melitensis by multiplex PCR as well as by real‐time PCR and conventional biotyping. Sixty‐two (87.3%) out of 71 strains were identified as B. melitensis biovar 3, eight (11,3%) strains as biovar 1 and only one (1,4%) as biovar 2. Digestion with PstI restriction enzyme revealed that all strains were field endemic strains, as they gave different patterns from the vaccine strain Rev.1. Brucella melitensis biovar 3 appears to be the predominant type in Greece. The novel multiplex PCR produced results concordant to ones obtained by real‐time PCR and conventional biotyping. This technique could support and facilitate the surveillance of Brucellosis in Greece contributing in the control of the disease.

Seroprevalence of brucellosis in goats and sheep in Thailand: Results from the Thai National Brucellosis Surveillance System from 2013 to 2015.

In Thailand, brucellosis re-emerged in humans in 2003 and is considered a public health risk to goat farmers as the disease is endemic in small ruminants. The Thai Department of Livestock Development (DLD) established a nationwide surveillance system for brucellosis in goats and sheep in 1997. Using data from this surveillance system, we describe the seroprevalence of brucellosis from 2013 to 2015 in small ruminants and the spatial distribution of the disease throughout Thailand. Surveillance data collected included the number of animals and herds tested, the province of the animal and herd and the laboratory results. Seroprevalence was estimated at both the animal and herd levels. During the 3-year period, 443,561 goats and sheep were tested for brucellosis by the DLD throughout Thailand using the Rose Bengal PlateTest (RBPT) and the enzyme-linked immunosorbent assay test for Brucella. Among the 3years, 2013 had the highest proportion of herds that tested positive for brucellosis at 13.80% (95% CI, 12.52, 15.16). Overall, this study found that brucellosis seroprevalence in small ruminants is decreasing throughout Thailand. However, there is variability in the spread of the disease with provinces in the eastern and western regions of Thailand having higher proportions of animals and herds testing positive. Overall provinces in the south had the lowest proportion of animals and herds testing positive for brucellosis. Periodic review of surveillance data documents the impact of the current brucellosis control programme and supports a targeted response in higher prevalence regions when there are limited financial resources for control measures.

Seroprevalence of Brucellosis in Butchers, Veterinarians and Slaughterhouse Workers in Hamadan, Western Iran.

Brucellosis is a zoonotic disease caused by Brucella species via infected domestic animals. In endemic areas, certain occupations such as veterinarians, butchers, and slaughterhouse workers are considered high risk regarding brucellosis. We evaluated the seroprevalence of brucellosis in high-risk occupations in Hamadan, West of Iran. a cross-sectional study. Overall, 218 participants from 2014 to 2015 were enrolled. A questionnaire including demographic data, length of employment, and using personal protective equipment was completed for each of them. Then, blood samples were taken and sent to Hamadan Health Center to be tested by Wright or standard tube agglutination (STA). In addition, samples with positive Wright test were examined by 2-mercaptoethanol (2ME) test. Then, seropositive participants were evaluated for clinical manifestations of brucellosis. All collected data were analyzed by SPSS ver. 16. The mean age of the participants was 42.79±11.16 yr and all seropositive cases were male. Based on Wright ≥1/80 and 2ME ≥1/40, seroprevalence of brucellosis was 13.3% and 12.3%, respectively. The use of personal protective equipment was low among individuals with or without brucellosis. Myalgia, fatigue, back pain, joint pain, night sweats, fever, malaise, and headache were common symptoms in seropositive cases. Moreover, 20.6% of the seropositive participants were asymptomatic. High prevalence of brucellosis in these occupational groups and symptomatic disease in significant numbers of them, so periodic clinical examinations in these groups seems to be essential for brucellosis surveillance system.

Study of knowledge about bovine brucellosis among people involved in the cattle supply chain in the province of Manabí, Ecuador.

A cross-sectional study was conducted to determine the level of knowledge about brucellosis among livestock farmers and their families, veterinary personnel, food processors and other people involved in the cattle supply chain in the province of Manabí. A voluntary, open-ended survey of participants was conducted in seven cantons in Manabí province selected at random: Bolívar, Chone, El Carmen, Jama, Junín, Sucre and Tosagua. Of the 500 people who responded to the survey, only 30% said they knew the disease. Greater knowledge about the disease was observed among people with a higher educational level, veterinarians, livestock farmers/traders and men. For all the aspects surveyed, only a small percentage of respondents (ranging from 0.6% to 30.2%) indicated that they had knowledge of that aspect of the disease. Only 29.8% of the respondents stated that they knew the clinical signs of the disease in cattle, which could jeopardise the brucellosis surveillance system. Only 7.6% of respondents knew the measures for reducing the risk of contracting brucellosis, leading to widespread high-risk practices when working with animals. The conclusion is that there is a low level of knowledge about the disease among people involved in the cattle supply chain in the province under study.

The Glutaminase-Dependent System Confers Extreme Acid Resistance to New Species and Atypical Strains of Brucella.

Neutralophilic bacteria have developed specific mechanisms to cope with the acid stress encountered in environments such as soil, fermented foods, and host compartments. In Escherichia coli, the glutamate decarboxylase (Gad)-dependent system is extremely efficient: it requires the concerted action of glutamate decarboxylase (GadA/GadB) and of the glutamate (Glu)/γ-aminobutyrate antiporter, GadC. Notably, this system is operative also in new strains/species of Brucella, among which Brucella microti, but not in the “classical” species, with the exception of marine mammals strains. Recently, the glutaminase-dependent system (named AR2_Q), relying on the deamination of glutamine (Gln) into Glu and on GadC activity, was described in E. coli. In Brucella genomes, a putative glutaminase (glsA)-coding gene is located downstream of the gadBC genes. We found that in B. microti these genes are expressed as a polycistronic transcript. Moreover, using a panel of Brucella genus-representative strains, we show that the AR2_Q system protects from extreme acid stress (pH ≤2.5), in the sole presence of Gln, only the Brucella species/strains predicted to have functional glsA and gadC. Indeed, mutagenesis approaches confirmed the involvement of glsA and gadC of B. microti in AR2_Q and that the acid-sensitive phenotype of B. abortus can be ascribed to a Ser248Leu substitution in GlsA, leading to loss of glutaminase activity. Furthermore, we found that the gene BMI_II339, of unknown function and downstream of the gadBC–glsA operon, positively affects Gad- and GlsA-dependent AR. Thus, we identified novel determinants that allow newly discovered and marine mammals Brucella strains to be better adapted to face hostile acidic environments. As for significance, this work may contribute to the understanding of the host preferences of Brucella species and opens the way to alternative diagnostic targets in epidemiological surveillance of brucellosis.