Characteristics of and risk factors for relapse of brucellosis in humans

Efficacy and safety of therapeutic strategies for human brucellosis: A systematic review and network meta-analysis

BACKGROUND

Human brucellosis is a neglected, re-emerging, and endemic zoonosis in many countries. The debilitating and disabling potential of the disease is a warning about its morbidity, generating socioeconomic impact. This review aims to update the current evidence on the efficacy and safety of therapeutic options for human brucellosis using the network meta-analysis (NMA).

METHODOLOGY

A systematic search was conducted in four different databases by independent reviewers to assess overall therapy failure, adverse events, and time to defervescence associated with different therapies. Randomized clinical trials (RCTs) evaluating any therapeutic drug intervention were selected, excluding non-original studies or studies related to localized forms of the disease or with less than 10 participants. Data were analyzed by frequentist statistics through NMA by random effects model. The risk of bias and certainty of evidence was assessed, this review was registered at PROSPERO.

RESULTS

Thirty-one (31) RCTs involving 4167 patients were included. Three networks of evidence were identified to evaluate the outcomes of interest. Triple therapy with doxycycline + streptomycin + hydroxychloroquine for 42 days (RR: 0.08; CI 95% 0.01-0.76) had a lower failure risk than the doxycycline + streptomycin regimen. Doxycycline + rifampicin had a higher risk of failure than doxycycline + streptomycin (RR: 1.96; CI 95% 1.27-3.01). No significant difference was observed between the regimens when analyzing the incidence of adverse events and time to defervescence. In general, most studies had a high risk of bias, and the results had a very low certainty of evidence.

CONCLUSIONS

This review confirmed the superiority of drugs already indicated for treating human brucellosis, such as the combination of doxycycline and aminoglycosides. The association of hydroxychloroquine to the dual regimen was identified as a potential strategy to prevent overall therapy failure, which is subject to confirmation in future studies.

Parenteral Vaccination with a Live Brucella melitensis Mutant Protects against Wild-Type B. melitensis 16M Challenge

Susceptibility to brucellosis remains prevalent, even in herds vaccinated with conventional vaccines. Efforts are underway to develop an improved brucellosis vaccine, and possibly a universal vaccine, given that Brucella species are highly homologous. To this end, two B. melitensis mutants were developed, znBM-lacZ (znBMZ) and znBM-mCherry (znBM-mC), and were tested for their ability to confer systemic immunity against virulent B. melitensis challenge. To assess the extent of their attenuation, bone-marrow-derived macrophages and human TF-1 myeloid cells were infected with both mutants, and the inability to replicate within these cells was noted. Mice infected with varying doses of znBM-mC cleared the brucellae within 6-10 weeks. To test for efficacy against systemic disease, groups of mice were vaccinated once by the intraperitoneal route with either znBMZ or B. abortus S19 vaccine. Relative to the PBS-dosed mice, znBMZ vaccination greatly reduced splenic brucellae colonization by ~25,000-fold compared to 700-fold for S19-vaccinated mice. Not surprisingly, both znBMZ and S19 strains induced IFN-γ+ CD4+ T cells, yet only znBMZ induced IFN-γ+ CD8+ T cells. While both strains induced CD4+ effector memory T cells (Tems), only znBMZ induced CD8+ Tems. Thus, these results show that the described znBM mutants are safe, able to elicit CD4+ and CD8+ T cell immunity without a boost, and highly effective, rendering them promising vaccine candidates for livestock.

Brucellosis: epidemiology, pathogenesis, diagnosis and treatment-a comprehensive review

Background: Brucellosis is a pervasive zoonotic disease caused by various Brucella species. It mainly affects livestock and wildlife and poses significant public health threats, especially in regions with suboptimal hygiene, food safety, and veterinary care standards. Human contractions occur by consuming contaminated animal products or interacting with infected animals. Objective: This study aims to provide an updated understanding of brucellosis, from its epidemiology and pathogenesis to diagnosis and treatment strategies. It emphasizes the importance of ongoing research, knowledge exchange, and interdisciplinary collaboration for effective disease control and prevention, highlighting its global health implications. Methods: Pathogenesis involves intricate interactions between bacteria and the host immune system, resulting in chronic infections characterized by diverse clinical manifestations. The diagnostic process is arduous owing to non-specific symptomatology and sampling challenges, necessitating a fusion of clinical and laboratory evaluations, including blood cultures, serological assays, and molecular methods. Management typically entails multiple antibiotics, although the rise in antibiotic-resistant Brucella strains poses a problem. Animal vaccination is a potential strategy to curb the spread of infection, particularly within livestock populations. Results: The study provides insights into the complex pathogenesis of brucellosis, the challenges in its diagnosis, and the management strategies involving antibiotic therapy and animal vaccination. It also highlights the emerging issue of antibiotic-resistant Brucella strains. Conclusions: In conclusion, brucellosis is a significant zoonotic disease with implications for public health. Efforts should be directed towards improved diagnostic methods, antibiotic stewardship to combat antibiotic resistance, and developing and implementing effective animal vaccination programs. Interdisciplinary collaboration and ongoing research are crucial for addressing the global health implications of brucellosis.

Recurrent Neurobrucellosis in a Feral Swine Hunter

Brucellosis is a zoonotic infectious disease caused by the bacterial genus Brucella and is most commonly transmitted to humans globally via the consumption of contaminated unpasteurized products. In a significant minority of cases, Brucella has been found to be transmitted by contact with infected swine bodily fluids such as blood. Only a small proportion of all cases of brucellosis affects the central nervous system, and of the four species of Brucella that are known to infect humans, Brucella suis is unusual. Neurologic involvement occurs in a limited proportion of cases and can vary in presentation, ranging from encephalitis to radiculitis or from brain abscess to neuritis. In this case report, we present a 20-year-old male with an eight-day history of headache and neck pain and a high fever that started two days after the onset of the headaches. Three weeks prior, he had hunted, killed, butchered, cooked, and eaten a wild boar in the field. A workup was performed, and blood cultures eventually grew Brucella suis. Although an intensive broad-spectrum antibiotic protocol was implemented, his post-therapy course was complicated. He eventually discontinued his antibiotics after one year.

Evaluation of an in-house IgM/IgG lateral flow assay for serodiagnosis of human brucellosis

This study aimed to evaluate the diagnostic efficacy of an in-house lateral flow assay (LFA) for the detection of IgM/IgG anti-Brucella antibodies for rapid serodiagnosis of human brucellosis. Three groups of sera samples including 476 from high-risk individuals, 27 from culture-confirmed patients, and 43 from healthy blood donors were used for evaluation of LFA. In comparison with iELISA, the sensitivity, specificity, and accuracy of LFA were >95%, >99%, and 99% respectively. Considering the very good agreement, accuracy, simplicity, and rapidity, LFAs might be useful as a point of care test for the diagnosis of human brucellosis in resource-limited laboratories.

Brucella suis in three dogs: presentation, diagnosis and clinical management

Brucella suis is an emerging, zoonotic disease predominantly affecting dogs and humans that engage in feral pig hunting in Australia and other countries. Although B. suis infection in dogs shares some clinical similarities to the host-adapted species (B. canis), B. suis remains an incompletely understood pathogen in dogs with limited published data on its pathogenesis and clinical features. This case series describes the presentations, diagnosis, and clinical management of B. suis infection in three dogs: (1) a bitch with dystocia, abortion and mastitis; (2) an entire male dog with septic arthritis and presumptive osteomyelitis; and (3) a castrated male dog with lymphadenitis. Unique features of these cases are reported including the first documented detection of B. suis from milk and isolation from lymph nodes of canine patients, as well as the follow-up of pups born to a B. suis-infected bitch. Consistent with previous reports, all three dogs showed a favourable clinical response to combination antibiotic therapy with rifampicin and doxycycline. Individually tailored drug regimens were required based on the clinical presentation and other factors, including owner expectations and compliance with therapy as well as a zoonotic risk assessment (generally considered low, except around time of whelping). The authors include their recommendations for the clinical management of dogs that are at-risk or seropositive for B. suis with or without clinical signs or laboratory-confirmed infection.

Brucella Infectious Aneurysm: A Retrospective Study of 14 Cases and Review of the Literature - Case Report and Literature Review

Objective

To analyze the clinical characteristics and treatment process of 14 patients with aneurysm due to brucellosis, summarize the morbidity characteristics, and improve the knowledge and diagnosis of the disease.

Methods

The clinical data of patients with aneurysms who were diagnosed to have brucellosis through Rose Bengal Test (RBT), Serum Agglutination Test (SAT), blood culture, and computed tomography angiography from January 2012 to November 2022 in Bethune Hospital, Shanxi Province, China, were retrospectively analyzed, and their clinical characteristics and disease regression findings were summarized.

Results

Of the 14 patients, 13 were men, and 1 was a woman; the youngest patient was 48-year-old, and the oldest patient was of 74 years. All had a history of smoking. The sites of lesion occurrence included the abdominal aorta (5 patients), abdominal aorta +iliac artery (5 patients), iliac artery (2 patients), thoracic aorta and brachial artery were less common (1 case each). Symptoms in the patients mostly began with abdominal pain, which was accompanied by fever, nausea, and vomiting. Six patients had a clear history of livestock exposure. Fourteen patients showed elevated D-dimer and C-reactive protein levels and decreased hemoglobin and albumin levels. Thirteen of the 14 cases were treated surgically, there were no complications of surgery, and 3 patients were readmitted with recurrence of brucellosis, it is related to the treatment that did not reach the early stage, combination, full dose and full course of treatment, with a mean recurrence time of 8 months. In the telephone follow-up, the patient's recovery proceeded well.

Conclusion

The present study revealed that the recurrence in male gender, advanced age, smoking and irregular treatment is higher. On the contrast, early intervention, a combination of adequate course of anti-infection treatment and timely surgery can improve the prognosis.

Activation of mucosal immunity as a novel therapeutic strategy for combating brucellosis

Brucellosis is a disease of livestock that is commonly asymptomatic until an abortion occurs. Disease in humans results from contact of infected livestock or consumption of contaminated milk or meat. Brucella zoonosis is primarily caused by one of three species that infect livestock, Bacillus abortus in cattle, B. melitensis in goats and sheep, and B. suis in pigs. To aid in disease prophylaxis, livestock vaccines are available, but are only 70% effective; hence, improved vaccines are needed to mitigate disease, particularly in countries where disease remains pervasive. The absence of knowing which proteins confer complete protection limits development of subunit vaccines. Instead, efforts are focused on developing new and improved live, attenuated Brucella vaccines, since these mimic attributes of wild-type Brucella, and stimulate host immune, particularly T helper 1-type responses, required for protection. In considering their development, the new mutants must address Brucella's defense mechanisms normally active to circumvent host immune detection. Vaccination approaches should also consider mode and route of delivery since disease transmission among livestock and humans is believed to occur via the naso-oropharyngeal tissues. By arming the host's mucosal immune defenses with resident memory T cells (TRMs) and by expanding the sources of IFN-γ, brucellae dissemination from the site of infection to systemic tissues can be prevented. In this review, points of discussion focus on understanding the various immune mechanisms involved in disease progression and which immune players are important in fighting disease.

Expression of NLRP3 and AIM2 inflammasome in Peripheral blood in Chinese patients with acute and chronic brucellosis

Brucellosis is a zoonotic disease caused by Brucella abortus. An efficient immune response is crucial for curing brucellosis. The inflammasome plays a significant role in the immune response. It is unclear which inflammasome is active in acute and chronic brucellosis and how its levels relate to inflammatory cytokines. A total of 40 patients with acute or chronic brucellosis and 20 healthy volunteers had peripheral blood samples collected. The expression levels of AIM2, NLRP3, ASC, and Caspase-1 were determined by a real-time polymerase chain reaction from RNA and serum samples, and IL-1β, IL-18, and IFN-γ were measured by enzyme-linked immunosorbent assay. In the acute brucellosis group, AIM2 expression was significantly higher, while ACS expression was significantly lower than that of healthy volunteers. In patients with chronic brucellosis, AIM2 expression was significantly lower, while Caspase-1 expression was significantly higher than that of healthy volunteers. Serum IL-18 and IFN-γ levels were significantly higher in patients with acute brucellosis than in healthy controls. The IFN-γ level was also significantly higher in patients with chronic brucellosis than in healthy controls. The inflammasome responds differently in different stages of brucellosis. The inflammasome may be the site of action of immune escape in brucellosis.

Antibiotic persistence of intracellular Brucella abortus

Background

Human brucellosis caused by the facultative intracellular pathogen Brucella spp. is an endemic bacterial zoonosis manifesting as acute or chronic infections with high morbidity. Treatment typically involves a combination therapy of two antibiotics for several weeks to months, but despite this harsh treatment relapses occur at a rate of 5–15%. Although poor compliance and reinfection may account for a fraction of the observed relapse cases, it is apparent that the properties of the infectious agent itself may play a decisive role in this phenomenon.

Methodology/Principal findings

We used B. abortus carrying a dual reporter in a macrophage infection model to gain a better understanding of the efficacy of recommended therapies in cellulo. For this we used automated fluorescent microscopy as a prime read-out and developed specific CellProfiler pipelines to score infected macrophages at the population and the single cell level. Combining microscopy of constitutive and induced reporters with classical CFU determination, we quantified the protective nature of the Brucella intracellular lifestyle to various antibiotics and the ability of B. abortus to persist in cellulo despite harsh antibiotic treatments.

Conclusion/Significance

We demonstrate that treatment of infected macrophages with antibiotics at recommended concentrations fails to fully prevent growth and persistence of B. abortus in cellulo, which may be explained by a protective nature of the intracellular niche(s). Moreover, we show the presence of bona fide intracellular persisters upon antibiotic treatment, which are metabolically active and retain the full infectious potential, therefore constituting a plausible reservoir for reinfection and relapse. In conclusion, our results highlight the need to extend the spectrum of models to test new antimicrobial therapies for brucellosis to better reflect the in vivo infection environment, and to develop therapeutic approaches targeting the persister subpopulation.

Brucellosis is a zoonosis endemic to many low- and middle-income countries around the world. Therapies recommended by the WHO are comprised of at least two antibiotics for several weeks, sometimes months. Relapses are frequent despite these harsh treatments. The underlying reasons for these relapses, besides reinfection and non-compliance to treatment, are unknown. Our study shows that Brucella abortus can form so called “persisters” in rich broth but also inside macrophages. This small bacterial subpopulation survives antibiotic treatment and resumes growth after removal of the antibiotics and could therefore serve as a reservoir for relapses in human brucellosis. Furthermore, we show that the intracellular lifestyle of Brucella has protective properties against recommended antibiotics as observed for other intracellular pathogens, highlighting the necessity to develop new infection models to assess antibiotic efficacy.

Infection agents of Didelphidae (Didelphimorphia) of Brazil: an underestimated matter in zoonoses research

Zoonoses are diseases or infections naturally transmissible from vertebrate animals to humans, and can be bacterial, viral or parasitic. The growth of urbanization, industrialization and the advance of agriculture and livestock facilitate the spread of infectious and parasitic agents from wild animals to the human population and to their domestic animals. Among the various reservoirs of zoonotic agents, we find that didelphid species, due to their high capacity for adaptation in urban environments, as an important study case. We reviewed the literature data on the pathogens, including with zoonotic potential of marsupial species occurring in Brazil, accounted for infections by agents that we categorized into Bacteria, Viruses, Protozoa, and Helminths. Aiming identifies possible knowledge gaps, we also surveyed the origin of studied samples and the institutions leading the researches on host didelphids. Among the hosts, the genus Didelphis in the cycles of these agents stands out. Moreover, we found that the majority of reported cases are in the Southeastern Brazil, mean the data from other Brazilian localities and didelphid species could be underestimated. Most studies took place in graduate programs of public research institutions, emphasizing the importance of the funding public research for the Brazilian scientific development.

Brucellosis Initially Misidentified as Ochrobactrum anthropi Bacteremia: A Case Report and Review of the Literature

Automated identification systems may misidentify Brucella, the causative agent of brucellosis, which may be re-emerging in the United States as the result of an expanding feral swine population. We present a case of Brucella suis likely associated with feral swine exposure that was misidentified as Ochrobactrum anthropi, a phylogenetic relative.

Risk factors, outcomes and time to detect positive blood culture among cases with acute brucellosis

BACKGROUND

Brucellosis causes a disabling human disease and loss of animals' lives. The clinical significance of Brucella bacteremia is still unclear and Brucella identification in blood culture is suboptimal.

METHODS

This was a retrospective study conducted in Medina in Saudi Arabia from August 2016 to May 2019. We included cases with brucellosis symptoms and a positive culture or serological evidence for brucellosis, comparing bacteremic with non-bacteremic brucellosis cases for the rates of complications, infection relapses and brucellosis development. Also, we estimated blood culture positivity rates and the time to detect Brucella in an automatic blood culture instrument.

RESULTS

Of the total number of 147 cases, 62 (42%) had a positive blood culture for Brucella, and the blood culture instrument (BACT/ALERT 3D) detected all positive blood cultures within 3 d of incubation. We found higher rates of chronic brucellosis in bacteremia than non-bacteremia cases (OR 7.25, 95% CI 1.41 to 37.23; p=0.018). Patients aged <15 y developed a higher rate of bacteremia than those aged ≥15 yr (OR 11.93 95% CI 1.37 to 103.75; p=0.025).

CONCLUSION

Brucella bacteremia is an independent predictor for the development of chronic infection. Brucella bacteremia cases may need long follow-up periods and a more thorough evaluation to exclude deep-seated infection.

Brucellosis in transplant recipients: A systematic review

BACKGROUND

Brucellosis is a bacterial disease caused by Brucella species. The purpose of this study was to evaluate brucellosis in all types of transplant patients.

METHODS

All the cases of brucellosis in transplant patients with no time and language limitations were searched and retrieved on May 20, 2020, using the following search keywords: (Brucella OR Brucellosis) AND (Transplant OR Transplantation) through the following medical databases: Web of Sciences, Google Scholar, Scopus, PubMed, and regional databases, for example, SID. All clinical features, including the time of transmission (before, during, and after transplantation), treatment protocols and medications, and patients' outcomes were investigated.

RESULTS

A total of 14 cases reported in 14 studies (out of 777 studies) were retrieved. Kidney (50%), liver (28.5%), and hematopoietic stem cell transplantation (14.2%) were the most reported types of transplantation. The presentation of brucellosis in 42.8% of the patients occurred in the early post-transplantation period, whereas 57.1% of the cases presented with late onset disease.

CONCLUSION

Brucellosis in transplant recipients seems to be uncommon even in the endemic regions. However, rare cases could be transmitted through bone marrow transplantation and transfusion. Precise screening and meticulous supervision during and after transplantation might lead to a reduction in the frequency of brucellosis.

Follow-up Brucellacapt and Rose Bengal Tests in 110 Children with Brucellosis

Objective The interpretation of serologic tests in brucellosis can be difficult because of nonspecific symptoms and vague signs of disease, and limitations of serological tests to distinguish persistent and cleared infection. Here, we evaluated the role of Brucellacapt test in conjunction with Rose Bengal test (RBT) in the follow-up of children treated for brucellosis.

Methods A total of 174 children diagnosed with brucellosis were included in the study. Data about demographic characteristics of patients, clinical and laboratory findings including Brucellacapt and RBT results, therapeutic approach, and response to treatment were collected from medical records.

Results Of the 174 cases, 109 (62.6%) were boys and 65 (37.4%) were girls. The mean age of children at the diagnosis was 122 ± 54 months. Sixty-four cases were excluded from the study for loss to follow-up. The follow-up period for the remained 110 cases was 4.3 ± 2.9 months. Eleven cases (10%) had persistent illness, 7 (6.4%) had recurrence/relapse, and 92 had favorable outcome. During the follow-up, Brucellacapt titers did not drop under 1/320 in cases with persistent illness, and it increased again to 1/320 in cases with relapses at average 6.1 months after treatment. In 48 of cases with favorable outcome, Brucellacapt titers decreased to 1/160 in average 3.3 ± 1.8 months; in 35 cases, RBT became negative in average 3.8 ± 2.5 months, and there was no statistically significant difference between them (p = 0.241). In cases with higher Brucellacapt titers on admission, decrement of titers took longer time.

Conclusion Persistent serological titers without clinical findings of brucellosis should not lead physician to prolong or repeat treatment because the decline in Brucellacapt titers and RBT negativity may be delayed in contrast to clinical recovery.

Improved Early Detection of Focal Brucellosis Complications with Anti-Brucella IgG

To evaluate the associations of inflammatory factors and serological test results with complicated brucellosis, we recruited 285 patients with a diagnosis of brucellosis between May 2016 and September 2019. The patients were subsequently classified into two groups according to the presence of complications. We collected demographic and clinical information and routine laboratory test results in addition to anti-Brucella IgG and IgM levels. Anti-Brucella IgG and IgM were uniformly tested using enzyme-linked immunosorbent assays (ELISAs) in this study. Among the 285 patients with brucellosis, 111 (38.95%) had complicated brucellosis. Osteoarthritis occurred more often in the subacute and chronic stages than in the acute stage (P = 0.002). Genital infection occurred more frequently in the acute stage than in the other stages (P = 0.023). Fever was not frequently observed in complicated cases (P < 0.001). The erythrocyte sedimentation rate (ESR) and the C-reactive protein (CRP) and anti-Brucella IgM and IgG levels were higher in complicated-brucellosis patients than in uncomplicated-brucellosis patients (P < 0.001). Anti-Brucella IgG, with an area under the curve of 0.885 (95% confidence interval [CI], 0.847 to 0.924), was the most robust indicator of complicated brucellosis. Positive culture, anti-Brucella IgM, the ESR, and CRP could be considered indicators, but their efficacy was weaker than that of IgG. In conclusion, a high ESR, high CRP, high anti-Brucella IgM and IgG levels, and positive culture were indicators of complicated brucellosis; among these, anti-Brucella IgG was the most robust biomarker.

Brucella abortus-infected platelets modulate the activation of neutrophils

Brucellosis is a contagious disease caused by bacteria of the genus Brucella. Platelets (PLTs) have been widely involved in the modulation of the immune response. We have previously reported the modulation of Brucella abortus-mediated infection of monocytes. As a result, PLTs cooperate with monocytes and increase their inflammatory capacity, promoting the resolution of the infection. Extending these results, in this study we demonstrate that patients with brucellosis present slightly elevated levels of complexes between PLTs and both monocytes and neutrophils. We then assessed whether PLTs were capable of modulating functional aspects of neutrophils. The presence of PLTs throughout neutrophil infection increased the production of interleukin-8, CD11b surface expression and reactive oxygen species formation, whereas it decreased the expression of CD62L, indicating an activated status of these cells. We next analyzed whether this modulation was mediated by released factors. To discriminate between these options, neutrophils were treated with supernatants collected from B. abortus-infected PLTs. Our results show that CD11b expression was induced by soluble factors of PLTs but direct contact between cell populations was needed to enhance the respiratory burst. Additionally, B. abortus-infected PLTs recruit polymorphonuclear (PMN) cells to the site of infection. Finally, the presence of PLTs did not modify the initial invasion of PMN cells by B. abortus but improved the control of the infection at extended times. Altogether, our results demonstrate that PLTs interact with neutrophils and promote a proinflammatory phenotype which could also contribute to the resolution of the infection.

Laboratory Diagnosis of Human Brucellosis

The clinical presentation of brucellosis in humans is variable and unspecific, and thus, laboratory corroboration of the diagnosis is essential for the patient's proper treatment. The diagnosis of brucellar infections can be made by culture, serological tests, and nucleic acid amplification assays. Modern automated blood culture systems enable detection of acute cases of brucellosis within the routine 5- to 7-day incubation protocol employed in clinical microbiology laboratories, although a longer incubation and performance of blind subcultures may be needed for protracted cases. Serological tests, though they lack specificity and provide results that may be difficult to interpret in individuals repeatedly exposed to Brucella organisms, nevertheless remain a diagnostic cornerstone in resource-poor countries. Nucleic acid amplification assays combine exquisite sensitivity, specificity, and safety and enable rapid diagnosis of the disease. However, long-term persistence of positive molecular test results in patients that have apparently fully recovered is common and has unclear clinical significance and therapeutic implications. Therefore, as long as there are no sufficiently validated commercial tests or studies that demonstrate an adequate interlaboratory reproducibility of the different homemade PCR assays, cultures and serological methods will remain the primary tools for the diagnosis and posttherapeutic follow-up of human brucellosis.

Combination versus monotherapy for the treatment of infections due to carbapenem-resistant Enterobacteriaceae

PURPOSE OF REVIEW

Combination therapy is a common strategy for treatment of multidrug resistant infections. Despite the strong twin rationales of improving efficacy and reducing resistance development, the evidence supporting this strategy remains controversial. The aims of this review are to assess the most recent studies supporting the use of combination therapy for treating infections because of carbapenem-resistant Enterobacteriaceae (CRE) and to highlight relevant areas for further research.

RECENT FINDINGS

Evidence supporting the use of combination therapy for the treatment of CRE remains limited to in-vitro experiments and observational studies with considerable risk of bias. Very few antibiotic combinations have been tested in well designed randomized controlled trials, making it difficult to draw general conclusions for clinical practice.

SUMMARY

Further studies are urgently needed to test the most promising synergistic combinations. New drugs potentially active against CRE should also to be tested in studies with adequate sample size and truly representative of the general patient population.

Detection of Brucellae in peripheral blood mononuclear cells for monitoring therapeutic efficacy of brucellosis infection

Background

Brucellosis is one of the most severe widespread zoonoses caused by the Gram-negative bacterium Brucella species. The diagnosis and clinical assessment of human brucellosis are very important for the management of patients, while there is a lack of effective methods to detect Brucellae. Classical culture of Brucella species is time consuming and often fails. A simple and sensitive assay is needed for diagnosis of Brucella infection and monitoring of treatment in man.

Methods

Blood samples and peripheral blood mononuclear cells (PBMCs) were collected from 154 patients hospitalized for brucellosis. Brucella antibodies were detected by Rose Bengal Plate Test (RBPT), Standard Tube Agglutination Test (SAT) and enzyme-linked immunosorbent assay (ELISA). Intracellular Brucellae were detected by blood culture and immunofluorescence staining (IFS).

Results

Among 154 brucellosis patients, 59.7% (92/154) were antibody reactive by RBPT, 81.8% (126/154) by SAT and 95.5% (147/154) by ELISA, respectively. Only 3.2% (5/154) of patient blood samples resulted in positive Brucella culture, while 68.8% (106/154) carried IFS detectable Brucella antigens in PBMCs. Gender (P = 0.01) but not age (P > 0.05) was a significant risk factor. The frequency of intracellular Brucella antigens was similar between patients receiving different treatment regimens (P > 0.05). However, a significant decrease of intracellular Brucellae was observed only in patients with acute brucellosis after the third course of treatment (P < 0.05), suggesting that current regimens to treat chronic brucellosis were not effective.

Conclusions

IFS appears a sensitive assay for detection of Brucella antigens in PBMCs and could be used for diagnosis and therapeutic monitoring of brucellosis in clinical practice.

An Outbreak of Brucellosis: An Adult and Pediatric Case Series

Background

Brucellosis is recognized as a neglected zoonotic disease and a major public health threat. The purpose of this study was to characterize epidemiological risk factors and healthcare utilization and compare clinical aspects of disease among adult and pediatric cases in North Texas.

Methods

A retrospective chart review of electronic medical records was completed at 3 large tertiary centers—Parkland Health and Hospital System, Clements University Hospital, and Children’s Medical Center—between January 1, 2007 and June 1, 2017. Demographic, clinical, and laboratory variables were collected. Cases were defined as confirmed or probable.

Results

Twenty-eight cases of brucellosis were identified: 26 confirmed (9 children, 17 adults) and 2 probable cases (1 child, 1 adult). Half (n = 14) were diagnosed in 2016 during an outbreak in Dallas County. Risk factors associated with infection were consumption of unpasteurized cheese (71%), recent travel (54%), close contact to a confirmed human brucellosis case (36%), and exposure to animals (11%). Median days of symptoms was 10 and 16 for children and adults, respectively. The majority (79%) of patients visited the emergency department before diagnosis and 93% were hospitalized. Fever was the most common symptom in children (80%) and adults (100%). Hepatitis (75% of children) and anemia (82% of adults) were the most common laboratory abnormalities. The most common complication in children was splenic lesions (40%), and the most common complication in adults was hepato/splenomegaly (39%).

Conclusions

The diagnosis of Brucella infection requires a high index of suspicion and should be considered in patients presenting with a febrile illness and a compatible exposure history.

The influence of illness duration before diagnosis on clinical characteristics and outcome in human brucellosis

Our study assesses the influence of illness duration before establishing the diagnosis of brucellosis and initiating therapy on patients' main clinical characteristics and outcome in an endemic area. The medical files of 297 patients with brucellosis were retrospectively analysed. They were divided into four groups according to illness duration before initiating therapy: <10 days; 11-30 days; 31-90 days; and >90 days. There were significant differences in the occurrences of fever (P = 0.019), focal forms (P = 0.026), spondylitis (P = 0.034) and therapeutic failures (P = 0.006) between the groups. Duration of >30 days before treatment initiation is responsible for more serious clinical presentation and outcome, whereas illness duration of >90 days further worsens the clinical progression in human brucellosis.

Clinical features of 2041 human brucellosis cases in China

BACKGROUND

Human brucellosis has become a major public health problem in China. However, the available clinical data on brucellosis cases are limited.

METHODS

We retrospectively reviewed medical charts of 2041 patients with confirmed human brucellosis and prospectively recorded their outcomes by telephone interview. These patients were admitted to the Sixth People's Hospital of the Xinjiang Uygur Autonomous region between 1st January and 31st December 2014. Data on these patients were collected from hospital medical records.

RESULTS

Many patients presented with fatigue (67%), fever (64%), arthralgia (63%) and sweating (54%). High erythrocyte sedimentation rate (ESR) (69%), high C-reactive protein (CRP) (39%), high alanine aminotransferase (ALT) (33%) and high aspartate aminotransferase (AST) (20%) were the most common laboratory findings, especially in acute patients. There was evidence of focal involvement in 90% of patients. A total of 61.5% of brucellosis patients recovered. Multivariate logistic regression analyses suggested that the risk factors key to unfavorable prognosis were: age≥45 years (OR = 1.75, 95% CI 1.36-2.24), back pain (OR = 1.50, 95% CI 1.16-1.94) and joint tenderness (OR = 1.73, 95% CI 1.13-2.65). The increasing duration of the illness increased the risk of poor prognosis.

CONCLUSION

Patients with brucellosis showed different characteristics in different clinical stages. In China, the chronicity rate of human brucellosis is high. The risk of poor prognosis is increased in patients aged 45 years or older, patients who have had brucellosis for a substantial period of time, and patients with back pain or joint tenderness. The clinical management of brucellosis should be improved to include sensitive diagnostic methods for subacute and chronic brucellosis.

The relationship between caspase-1 related inflammasome expression and serum inflammatory cytokine levels during acute brucellosis

OBJECTIVE

Brucellosis is a zoonotic disease caused by Brucella in domestic and wild animals. It also causes systemic diseases with the involvement of different parts of the human body. An efficient innate immune response is crucial to cure brucellosis with optimum antibiotic treatment. The inflammasomes are innate immune system receptors and sensors that regulate the activation of cysteine-dependent aspartate specific protease-1 (caspase-1) and caspase-1-induced cell death process known as pyroptosis. The aim of the present study was to investigate the expression levels of CASPASE-1 and associated inflammasomes AIM2, NLRP3, and NLRC4 to analyze their relationship with the inflammatory cytokine interleukin (IL)-1β, IL-18, and interferon-gamma (IFN-γ) in peripheral blood samples of patients with acute brucellosis with healthy controls.

METHODS

Peripheral blood samples were obtained from 20 healthy volunteers and 20 patients with acute brucellosis. RNA and serum samples were isolated to examine the expression levels of AIM2, NLRP3, NLRC4, and CASPASE-1 by real-time polymerase chain reaction, and IL-1β, IL-18, and IFN-γ were measured by enzyme-linked immunosorbent assay.

RESULTS

In the acute brucellosis group, AIM2 and NLRC4 expressions were significantly higher than in healthy volunteers. A significant increase on caspase-1 expression in patients with acute brucellosis was not observed. Serum IL-18 and IFN-γ levels were significantly higher in patients with acute brucellosis than in healthy controls.

CONCLUSION

Caspase-1-related inflammasomes are sufficiently activated to induce the secretion of cytokines, such as IFN-γ and IL-18, to induce cellular immune response. Caspase-1 activation level should be investigated at different periods of disease in a group with high number of patients to understand the role of pyroptosis and caspase-1 in brucellosis.

Platelets Promote Brucella abortus Monocyte Invasion by Establishing Complexes With Monocytes

Brucellosis is an infectious disease elicited by bacteria of the genus Brucella. Platelets have been extensively described as mediators of hemostasis and responsible for maintaining vascular integrity. Nevertheless, they have been recently involved in the modulation of innate and adaptive immune responses. Although many interactions have been described between Brucella abortus and monocytes/macrophages, the role of platelets during monocyte/macrophage infection by these bacteria remained unknown. The aim of this study was to investigate the role of platelets in the immune response against B. abortus. We first focused on the possible interactions between B. abortus and platelets. Bacteria were able to directly interact with platelets. Moreover, this interaction triggered platelet activation, measured as fibrinogen binding and P-selectin expression. We further investigated whether platelets were involved in Brucella-mediated monocyte/macrophage early infection. The presence of platelets promoted the invasion of monocytes/macrophages by B. abortus. Moreover, platelets established complexes with infected monocytes/macrophages as a result of a carrier function elicited by platelets. We also evaluated the ability of platelets to modulate functional aspects of monocytes in the context of the infection. The presence of platelets during monocyte infection enhanced IL-1β, TNF-α, IL-8, and MCP-1 secretion while it inhibited the secretion of IL-10. At the same time, platelets increased the expression of CD54 (ICAM-1) and CD40. Furthermore, we showed that soluble factors released by B. abortus-activated platelets, such as soluble CD40L, platelet factor 4, platelet-activating factor, and thromboxane A₂, were involved in CD54 induction. Overall, our results indicate that platelets can directly sense and react to B. abortus presence and modulate B. abortus-mediated infection of monocytes/macrophages increasing their pro-inflammatory capacity, which could promote the resolution of the infection.

Alternative strategies for vaccination to brucellosis

Brucellosis remains burdensome for livestock and humans worldwide. Better vaccines for protection are needed to reduce disease incidence. Immunity to brucellosis and barriers to protection are discussed. The benefits and limitations of conventional and experimental brucellosis vaccines are outlined, and novel vaccination strategies needed to ultimately protect against brucellosis are introduced.

Quantitative polymerase chain reaction based quantification of Brucella DNA in serum of pre- and post-therapeutic occupationally exposed infected human population

BACKGROUND

Brucellosis is one of the neglected zoonotic diseases in humans. The serological methods based on antibody detections are unable to detect the effectiveness of treatment in humans as antibodies persist for long time in humans even after therapy. Therefore, we developed qPCR technique to overcome such discrepancy and device a rapid and efficient test for both diagnosis and follow up of the brucellosis affected individuals.

METHODS

High risk suspected individuals with positive serology (RBPT, STAT and iELISA) and PCR were mainly analyzed for DNA quantification by qPCR assay. The bcsp-31 gene, a shared gene of Brucella species was amplified by genus specific primers and cloned to pGEMT™ easy vector and the cloned plasmid were used to construct a standard curve (R²=0.99, efficiency=1.98) over 7 orders of magnitude with sensitivity of ≈10 copy number. The assay was found 100% specific.

RESULTS

Overall 85 individuals were found positive out of 188. Out of them, 23 serological, PCR and qPCR positive individuals were recommended for 45days therapy according to WHO regimen (Doxycycline and Rifampin) and each case was further followed by qPCR. The mean threshold cycle (C_q) before treatment was 26.05±0.347 (3940.5copies/μl), which increased significantly to 32.7±0.66 (259.13copies/μl) on 4th week during treatment, 35.12±3.12 (38.52copies/μl) at 6th week on day of treatment completion, 35.6±0.66 (34.21copies/μl) on 21st day after treatment depicting a significant reduction in DNA load over the course of treatment. Serological follow up showed that only 3 individuals had decreased STAT titre but no change in RBPT results. Out of 17 symptomatic individuals under therapy, 10 improved clinically, 5 improved clinically with persistent weakness and 2 had no effect of therapy.

CONCLUSION

The study suggests that qPCR is more useful and rapid test to follow treated individuals than serology.

Prevalence and factors associated with human brucellosis in livestock professionals

OBJECTIVE

The objective of this study is to estimate the seroprevalence of human brucellosis in livestock professionals and analyze the factors associated with brucellosis focusing on sociodemographic variables and the variables of knowledge and practices related to the characteristics of the activities carried out in livestock.

METHODS

This is a cross-sectional seroepidemiological study with a population of 131 workers of butchers, slaughter rooms, and slaughterhouse and 192 breeders sampled randomly in Namibe province, Angola. The data were obtained from the collection of blood and use of questionnaires. The laboratory tests used were rose bengal and slow agglutination. The questionnaire allowed us to collect sociodemographic information and, specifically on brucellosis, it incorporated questions about knowledge, attitudes, and behaviors of livestock professionals. In addition to the descriptive statistical approach, we used the Chi-square test of independence, Fisher's test, and logistic regression models, using a significance level of 10%.

RESULTS

The general weighted prevalence of brucellosis was 15.6% (95%CI 13.61-17.50), being it 5.3% in workers and 16.7% (95%CI 11.39-21.93) in breeders. The statistical significance was observed between human seroprevalence and category (worker and breeder) (p < 0.001) and education level (p = 0.032), start of activity (p = 0079), and service location (p = 0.055). In a multivariate context, the positive factor associated with brucellosis in professionals was the professional category (OR = 3.54; 95%CI 1.57-8.30, related to breeders in relation to workers).

CONCLUSIONS

Human brucellosis in livestock professionals is prevalent in Namibe province (15.6%), where the professional category was the most important factor. The seroprevalence levels detected are high when compared with those found in similar studies.

OBJECTIVO

Estimar a seroprevalência da brucelose humana em profissionais da pecuária e analisar os factores associados à brucelose com foco em variáveis sociodemográficas, de conhecimento e práticas relativas às características das actividades desenvolvidas na pecuária.

MÉTODOS

Estudo transversal seroepidemiológico em população de 131 trabalhadores de talhos, salas de abate e matadouro e 192 criadores amostrados aleatoriamente na província do Namibe, Angola. Os dados foram obtidos por meio de colheita de sangue e aplicação de questionário. Os testes laboratoriais utilizados foram o Rosa de Bengala e a aglutinação lenta em tubos. O questionário permitiu recolher informação sociodemográfica e, especificamente sobre a brucelose, incorporou questões sobre conhecimento, atitudes e comportamentos dos profissionais da pecuária. Além da abordagem estatística descritiva, foram utilizados os testes de Independência do Qui-quadrado, Fisher e modelos de regressão logística, utilizando um nível de significância de 10%.

RESULTADOS

A prevalência geral ponderada da brucelose foi de 15.6% (IC95% 13.61-17.50), sendo 5.3% em trabalhadores e 16.7% (IC95% 11.39-21.93) em criadores. A significância estatística foi observada entre a seroprevalência humana e a categoria (trabalhador e criador) (p < 0.001) e o nível de instrução (p = 0.032), início de actividade (p = 0.079) e local de serviço (p = 0.055). Em um contexto multivariado, o factor positivamente associado à brucelose em profissionais foi a categoria profissional (OR = 3.54; IC95% 1.57-8.30, relativo aos criadores em relação a trabalhadores).

CONCLUSÕES

A brucelose humana em profissionais da pecuária é prevalente na província do Namibe (15.6%), onde a categoria profissional foi o factor mais relevante. Os níveis de seroprevalência detectados são elevados se comparados com outros encontrados em estudos semelhantes.

Lessons learned with molecular methods targeting the BCSP-31 membrane protein for diagnosis of human brucellosis

Brucellosis remains an emerging and re-emerging zoonosis worldwide causing high human morbidity. It usually affects persons who are permanently exposed to fastidious microorganisms of the Brucella genus and has a nonspecific clinical picture. Thus, diagnosis of brucellosis can sometimes be difficult. Molecular techniques have recently been found very useful in the diagnosis of brucellosis together with its common and very diverse focal complications. We herein review all the lessons learned by our group concerning the molecular diagnosis of human brucellosis over the last twenty years. The results, initially using one-step conventional PCR, later PCR-ELISA and more recently real-time PCR, using both fluorescent intercalating reagents (SYBR-Green I) and specific probes (Taqman), have shown that these techniques are all much more sensitive than bacteriological methods and more specific than the usual serological techniques for the diagnosis of primary infection, the post-treatment control of the disease, early detection of relapse and the diagnosis of focal complications. Optimization of the technique and improvements introduced over the years show that molecular methods, currently accessible for most clinical laboratories, enable easy rapid diagnosis of brucellosis at the same time as they avoid any risk to laboratory personnel while handling live Brucella spp.

Childhood brucellosis: Review of 317 cases

OBJECTIVE

To describe the main epidemiological, clinical, and laboratory features, treatment options and outcome in children with brucellosis.

METHODS

Retrospectively evaluated data were obtained from 317 pediatric patients with brucellosis that were treated at the University Clinic for Infectious Diseases and Febrile Conditions in Skopje, during the period from 1989 to 2011. The medical records and follow-up protocols were used for evaluation.

RESULTS

Childhood brucellosis composed 317 (18.7%) of 1691 patients with brucellosis. The patients were median 9 years old, ranging from 7 months to 14 years, and 201 (63.4%) were males. Family history was present in 197 (62.1%), and direct contact with animals occurred in 140 (44.2%) of the children. The dominant manifestations were fever in 248 (78.2%), joint pain in 228 (71.9%) and hepatomegaly in 216 (68.1%). Organ affection was present in 206 (65.0%) of the patients. One hundred and six (33.4%) of the patients were treated with combination composed of two, and 211 (66.6%) with three antimicrobial agents. Relapses were registered in 21 (6.6%), and therapeutic failures in 3 (0.9%) of the children.

CONCLUSIONS

In endemic regions childhood brucellosis represents a significant part of human cases. Wide spectrum of clinical manifestations, frequent affection of various organ systems and possibility of relapses show that brucellosis could be a serious disease in this age group. The presence of fever, joint pain, sweating, and affection of various systems in children from endemic regions should alert pediatricians for the possibility of brucellosis.

Epidemiological, diagnostic, clinical, and therapeutic aspects of Brucella bacteremia in children in southern Israel: a 7-year retrospective study (2005-2011)

BACKGROUND

Data on the various aspects of brucellosis in children living in southern Israel are missing.

OBJECTIVES

Our aim was to study the epidemiological, microbiological, diagnostic, clinical, therapeutic and outcome features of brucellosis in children <19 years of age in southern Israel during 2005-2011.

PATIENTS AND METHODS

The study population included all patients hospitalized with a diagnosis of brucellosis, established according to a clinical presentation compatible with brucellosis+presence of Brucella bacteremia (BB).

RESULTS

A total of 128 (50.8%) of 252 patients admitted with a diagnosis of brucellosis had BB (all with Brucella melitensis). All patients were of Muslim Bedouin ethnicity. The mean incidence of BB in southern Israel was 16 cases/100,000 Bedouin, with no significant changes during the study period. Overall duration of symptoms before diagnosis was 10.1±10.9 days. Fever at diagnosis was recorded in <20% of the patients. The most frequent symptoms were arthralgia (61.7%), weakness (32.8%), gastrointestinal disturbances (27.3%), myalgia (25%), and headache (18.8%). The main clinical findings included monoarthritis (36.7%), hepatosplenomegaly (25%), lymphadenopathy (17.2%), heart murmur (11.7%), and skin rash (9.4%), respectively. Anemia, leukopenia, thrombocytopenia, and pancytopenia were reported in 17.6%, 29.6%, 12.8%, and 2.3% of the patients, respectively. Twenty-nine (30.5%) patients with BB had serum agglutinin titers ≤1/160 (13, 13.7%%, had titers <1/160). Twenty-seven (93%) of the 29 patients aged 0-4 years were treated with gentamicin and trimethoprim-sulfamethoxazole; a total of 77 (60.2%) patients received gentamicin and doxycycline.

CONCLUSIONS

Childhood brucellosis remains an important public health problem in southern Israel. BB was diagnosed in >50% of the children with brucellosis, and B. melitensis was identified in all cases. Arthralgia, weakness, and gastrointestinal complaints were the most common symptoms, and monoarthritis, hepatosplenomegaly, and lymphadenopathy were the most common clinical findings. A considerable number of patients with BB had undetectable/low serum agglutinin titers, suggesting insufficient reliability on serology alone in diagnosis of brucellosis.

Prevalence of Brucella antibodies on a previously acute brucellosis infected population: sensitivity, specificity and predictive values of Rose Bengal and Wright standard tube agglutination tests

PURPOSE

Brucellosis is a zoonosis with worldwide distribution. The presence of antibodies after acute infection and the prevalence of positive serology in endemic area are not well documented.

METHODS

Patients hospitalized with acute brucellosis were relocated 3-13 years after the initial infection. Hospital records of the initial infection were retrieved, and examination of Brucella antibodies using Rose Bengal test (RBT) and Wright standard tube agglutination (STA) test was performed.

RESULTS

Eighty-three patients were hospitalized from 2000 to 2010; 50.6 % were farmers and 37.4 % livestock farmers. All had febrile illness and various focal complications. All had positive serology, and 82.2 % had positive blood cultures; 91.5 % were treated with streptomycin plus doxycycline. Seventy-two (86.7 %) were relocated on follow-up. Nine (12.5 %) had positive RBT and STA up to 1/320. Occupational history was associated with positive serology (p = 0.0172), and 8/9 of the positive individuals were livestock farmers (38.0 % of the livestock farmers checked). Residence, years after the infection, clinical presentation of brucellosis and treatment were not associated with serology results. Both tests had excellent sensitivity (nearly 100 %), specificity 87.5 % and excellent negative predictive value (nearly 100 %); however, positive predictive value was only 11.4 %.

CONCLUSIONS

Rapid and low-cost tests as RBT and STA are still very useful in diagnosing acute brucellosis; however, every positive test must be examined together with clinical symptoms and occupational history. The tests can be used as screening tests in endemic populations to rule out acute brucellosis.

Brucella melitensis invades murine erythrocytes during infection

Brucella spp. are facultative intracellular Gram-negative coccobacilli responsible for brucellosis, a worldwide zoonosis. We observed that Brucella melitensis is able to persist for several weeks in the blood of intraperitoneally infected mice and that transferred blood at any time point tested is able to induce infection in naive recipient mice. Bacterial persistence in the blood is dramatically impaired by specific antibodies induced following Brucella vaccination. In contrast to Bartonella, the type IV secretion system and flagellar expression are not critically required for the persistence of Brucella in blood. ImageStream analysis of blood cells showed that following a brief extracellular phase, Brucella is associated mainly with the erythrocytes. Examination by confocal microscopy and transmission electron microscopy formally demonstrated that B. melitensis is able to invade erythrocytes in vivo. The bacteria do not seem to multiply in erythrocytes and are found free in the cytoplasm. Our results open up new areas for investigation and should serve in the development of novel strategies for the treatment or prophylaxis of brucellosis. Invasion of erythrocytes could potentially protect the bacterial cells from the host's immune response and hamper antibiotic treatment and suggests possible Brucella transmission by bloodsucking insects in nature.

Emergence of quinolone-resistant, topoisomerase-mutant Brucella after treatment with fluoroquinolones in a macrophage experimental infection model

AIM OF THE STUDY

To determine the activity of fluoroquinolones (FQ) and the selection of FQ-resistant mutants in a macrophage experimental infection model (MEIM).

MATERIAL AND METHODS

Canine macrophages were inoculated with Brucella melitensis ATCC 23457 (WT), achieving intracellular counts of around 105 CFU/mL. Cell cultures were incubated in the presence of ciprofloxacin (CIP), levofloxacin (LEV), moxifloxacin (MOX), and doxycycline (DOX). After cell lysis, surviving microorganisms were plated for count purposes, and plated onto antibiotics-containing media for mutant selection. Topoisomerases mutations were detected by PCR and sequencing.

RESULTS

Bacterial counts after cell lysis were 14.3% (CIP), 65.3% (LEV), and 75% (MOX) lower compared to the control. Quinolone-resistant mutants emerged in cell cultures containing CIP and LEV with a frequency of around 0.5×10(-3). All mutants showed an Ala87Val change in GyrA. Mutants had FQs MICs around 10×WT. The ability of these mutants for infecting new macrophages and the intracellular lysis after antibiotic exposure did not change significantly. No 2nd step FQ-resistant mutants were selected from 1st step mutants.

CONCLUSIONS

Intracellular activity of FQs is low against WT and gyrA-mutant Brucella. FQs easily select gyrA mutants in MEIM. The ability of mutants for infecting new macrophages remains unchanged. In this MEIM, 2nd step mutants do not emerge.

Osteoarticular involvement in childhood brucellosis: experience with 133 cases in an endemic region

AIM

To describe the main clinical and laboratory characteristics, frequency and distribution of osteoarticular involvement, therapeutic options and outcome in children with osteoarticular brucellosis.

METHODS

This descriptive study includes 133 pediatric patients with osteoarticular brucellosis who were treated at the University Clinic for Infectious Diseases and Febrile Conditions in Skopje, Republic of Macedonia, during the period between 1989 and 2011. Brucellosis was presumptively diagnosed on the basis of clinical signs and confirmed by the detection of specific antibodies at significant titers.

RESULTS

The median age of patients was 9 years (range, 2-14 years) and 63.9% were males. Family history of brucellosis was present in 54.1%. The dominant clinical symptoms were arthralgia and fever in 77.4% and 73.7%, respectively, and the dominant sign was hepatomegaly in 73.7% of patients. The main laboratory abnormalities were elevated C-reactive protein (81.0%) and circulating immunocomplexes (80.7%). In 71.4% of patients, the osteoarticular involvement was monoarticular. Hip arthritis was present in 49.6%, followed by the knee in 30.1%. Various therapeutic regimens with a duration of 6 weeks were used. In 87 patients during a follow-up of at least 6 months, relapse occurred in 13.8%.

CONCLUSIONS

Osteoarticular involvement is frequent in children with brucellosis. It is most often manifested with monoarthritis of the large weight-bearing joints. Brucellosis should be included in the differential diagnosis of childhood arthritis in endemic countries, especially in the presence of family history, contact with infected animals or ingestion of unpasteurized food products, fever and hepatomegaly.

Herd-level risk factors for Campylobacter fetus infection, Brucella seropositivity and within-herd seroprevalence of brucellosis in cattle in northern Nigeria

Brucellosis and campylobacteriosis are economically important diseases affecting bovine reproductive efficiency in Nigeria. A questionnaire-based survey was conducted in 271 cattle herds in Adamawa, Kaduna and Kano states of northern Nigeria using multistage cluster sampling. Serum from 4745 mature animals was tested for Brucella antibodies using the Rose-Bengal plate test and positives were confirmed in series-testing protocol using competitive enzyme-linked immunosorbent assay. Preputial scrapings from 602 bulls were tested using culture and identification for Campylobacter fetus. For each disease, a herd was classified as positive if one or more animals tested positive. For each herd, information on potential managemental and environmental risk factors was collected through a questionnaire administered during an interview with the manager, owner or herdsman. Multiple logistic regression models were used to model the odds of herd infection for each disease. A zero-inflated Poisson model was used to model the count of Brucella-positive animals within herds, with the number tested as an exposure variable. The presence of small ruminants (sheep and/or goats) on the same farm, and buying-in of >3 new animals in the previous year or failure to practice quarantine were associated with increased odds of herd-level campylobacteriosis and brucellosis, as well as increased within-herd counts of Brucella-positive animals. In addition, high rainfall, initial acquisition of animals from markets, practice of gynaecological examination and failure to practice herd prophylactic measures were positively associated with the odds of C. fetus infection in the herd. Herd size of >15, pastoral management system and presence of handling facility on the farm were associated with increased odds, and gynaecological examination with reduced odds of herd-level Brucella seropositivity. Furthermore, the zero-inflated Poisson model showed that borrowing or sharing of bulls was associated with higher counts, and provision of mineral supplement with lower counts of Brucella-positive cattle within herds. Identification of risk factors for bovine campylobacteriosis and brucellosis can help to identify appropriate control measures, and the use of zero-inflated count model can provide more specific information on these risk factors.

Asymptomatic brucellosis infection in humans: implications for diagnosis and prevention

Human brucellosis is mainly caused by contact with Brucella-infected animals and their secretions and carcasses. Individuals who are continuously in contact with animals are considered to be at a high risk but only some show symptoms and are diagnosed as cases of brucellosis. Here, we showed that asymptomatic brucellosis infections occur among humans. Asymptomatic infections mainly result from less frequent contact with Brucella and/or contact with low-virulence Brucella. In our study, patients with asymptomatic infection had low antibody titres and different contact patterns. Awareness of asymptomatic infection is important for early diagnosis of brucellosis and prevention of chronic infection.

Comparison of total antibody and interferon-γ T-cell responses in patients following infection with brucellosis in Georgia

Brucellosis is an ancient disease that still remains a significant threat to humans and is typically linked to exposure to infected animals and/or consumption of unpasteurized animal products. Despite this history, we have a relatively limited understanding of the host characteristics of this disease; consequently, further research is necessary. In this study, we examined the humoral immune response in 43 Georgian individuals that had been diagnosed with brucellosis 3-12 months before enrollment in the study, many of whom still had symptoms after the completion of antibiotic therapy. In total, 35 of 43 (83%) of the patients had antibodies that bound to Brucella lipopolysaccharide (LPS) by COMPELISA, and 34 of 38 (89%) patients had demonstrable specific antibodies to Brucellergene™ antigens; the results from the two ELISAs were highly correlated (p=0.031, r=0.851). We also studied the cellular immune responses in 15 patients. All of the patients generated interferon (IFN)-γ in response to ex vivo stimulation with Brucella protein antigens, and the majority of the patients maintained measurable humoral responses to both LPS and protein antigens. From this initial study, we conclude that measurement of antibody and of cellular (IFN-γ) responses to brucellergene OCB protein epitopes may be worthy of further investigation as an alternative or adjunct to current diagnostics.

IFN-γ-deficient mice develop IL-1-dependent cutaneous and musculoskeletal inflammation during experimental brucellosis

Human brucellosis exhibits diverse pathological manifestations that can affect almost any organ. In particular, osteoarticular complications are the most common focal manifestation of brucellosis and occur in 40-80% of patients. In immunocompetent mice, Brucella replication is generally restricted to the spleen, liver, and to a lesser extent, LNs, thereby limiting their use for study of focal inflammation often found in brucellosis. Here, we report that nasal, oral, or peritoneal infection of IFN-γ(-/-) mice with WT Brucella melitensis or Brucella abortus results in joint and periarticular tissue inflammation. Histological analysis of the affected joints revealed inflammatory infiltrates and debris within the joint space colocalizing with Brucella antigen. Osteoarthritis, necrosis, periarticular soft tissue inflammation, and substantial brucellae burdens were observed. Oral rifampicin was effective in clearing infection and halting further progression of focal inflammation from infected IFN-γ(-/-) mice, although some symptoms and swelling remained. Elevated IL-1 β, but not TNF-α, IL-6, or IL-17, was detected in joint homogenates from infected IFN-γ(-/-) mice. Whereas more susceptible to systemic infection, IL-1R(-/-) mice depleted of IFN-γ were more resistant to focal inflammation than WT mice similarly depleted of IFN-γ. Collectively, these results show IFN-γ(-/-) mice represent a potential model for study of focal inflammation attributed to Brucella infection and will allow evaluation of intervention strategies targeting IL-1, IL-1R, or other inflammatory mediators, with the potential to complement antibiotic-based therapies.

Systematic review and meta-analysis of randomized clinical trials in the treatment of human brucellosis

Background

Brucellosis is a persistent health problem in many developing countries throughout the world, and the search for simple and effective treatment continues to be of great importance.

Methods and Findings

A search was conducted in MEDLINE and in the Cochrane Central Register of Controlled Trials (CENTRAL). Clinical trials published from 1985 to present that assess different antimicrobial regimens in cases of documented acute uncomplicated human brucellosis were included. The primary outcomes were relapse, therapeutic failure, combined variable of relapse and therapeutic failure, and adverse effect rates. A meta-analysis with a fixed effect model was performed and odds ratio with 95% confidence intervals were calculated. A random effect model was used when significant heterogeneity between studies was verified.

Comparison of combined doxycycline and rifampicin with a combination of doxycycline and streptomycin favors the latter regimen (OR = 3.17; CI95% = 2.05–4.91). There were no significant differences between combined doxycycline-streptomycin and combined doxycycline-gentamicin (OR = 1.89; CI95% = 0.81–4.39). Treatment with rifampicin and quinolones was similar to combined doxycycline-rifampicin (OR = 1.23; CI95% = 0.63–2.40). Only one study assessed triple therapy with aminoglycoside-doxycycline-rifampicin and only included patients with uncomplicated brucellosis. Thus this approach cannot be considered the therapy of choice until further studies have been performed. Combined doxycycline/co-trimoxazole or doxycycline monotherapy could represent a cost-effective alternative in certain patient groups, and further studies are needed in the future.

Conclusions

Although the preferred treatment in uncomplicated human brucellosis is doxycycline-aminoglycoside combination, other treatments based on oral regimens or monotherapy should not be rejected until they are better studied. Triple therapy should not be considered the current treatment of choice.