Disease Occurrence in- and the Transferal of Zoonotic Agents by North American Feedlot Cattle

North America is a large producer of beef and contains approximately 12% of the world's cattle inventory. Feedlots are an integral part of modern cattle production in North America, producing a high-quality, wholesome protein food for humans. Cattle, during their final stage, are fed readily digestible high-energy density rations in feedlots. Cattle in feedlots are susceptible to certain zoonotic diseases that impact cattle health, growth performance, and carcass characteristics, as well as human health. Diseases are often transferred amongst pen-mates, but they can also originate from the environment and be spread by vectors or fomites. Pathogen carriage in the gastrointestinal tract of cattle often leads to direct or indirect contamination of foods and the feedlot environment. This leads to the recirculation of these pathogens that have fecal-oral transmission within a feedlot cattle population for an extended time. Salmonella, Shiga toxin-producing Escherichia coli, and Campylobacter are commonly associated with animal-derived foods and can be transferred to humans through several routes such as contact with infected cattle and the consumption of contaminated meat. Brucellosis, anthrax, and leptospirosis, significant but neglected zoonotic diseases with debilitating impacts on human and animal health, are also discussed.

Çocukluk çağında bruselloz: 37 olgunun retrospektif değerlendirilmesi ve literatürün gözden geçirilmesi

Introduction: The aim of this study is to evaluate the demographic, clinical and laboratory characteristics and treatment results of pediatric patients followed up with the diagnosis of brucellosis in our clinic.Methods: Patients who were followed up with the diagnosis of brucellosis in Kayseri Training and Research Hospital, Pediatric Infectious Diseases Clinic between October 2016 and December 2018 were retrospectively analyzed.Results: A total of 37 patients, 26 (70.3%) male, were included in the study. The mean age of the patients whose ages ranged from 1 to 17 years was 9.3±4.3 years. Unpasteurized milk and/or dairy products were consumed in 86.5% of the patients and 48.6% had a family history of brucellosis. Joint pain (75.7%) was the most common presenting complaint. In the laboratory evaluation, 8.1% of the patients had leukopenia, 2.7% had thrombocytopenia and 21.4% had ALT elevation. Doxycycline plus rifampicin (43.2%) was the most commonly preferred treatment regimen. Addition of aminoglycoside to initial therapy in hospitalized patients was statistically higher than in outpatients (81.2% vs. 23.8%) (p=0.001). During the follow-up, relapse developed in a total of 4 (10.8%) patients, 3 of whom were outpatients. There was no statistical relationship between the initial treatment regimen and relapse (p=0.418).Conclusion: In conclusion, brucellosis should be kept in mind in terms of differential diagnosis in patients who present with joint pain in our country and who have cytopenia and/or isolated aminotransferase elevation in their investigations.Keywords: Child, Brucellosis, Relapse

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.

Brucella suppress STING expression via miR-24 to enhance infection

Brucellosis, caused by a number of Brucella species, remains the most prevalent zoonotic disease worldwide. Brucella establish chronic infections within host macrophages despite triggering cytosolic innate immune sensors, including Stimulator of Interferon Genes (STING), which potentially limit infection. In this study, STING was required for control of chronic Brucella infection in vivo. However, early during infection, Brucella down-regulated STING mRNA and protein. Down-regulation occurred post-transcriptionally, required live bacteria, the Brucella type IV secretion system, and was independent of host IRE1-RNase activity. STING suppression occurred in MyD88-/- macrophages and was not induced by Toll-like receptor agonists or purified Brucella lipopolysaccharide (LPS). Rather, Brucella induced a STING-targeting microRNA, miR-24-2, in a type IV secretion system-dependent manner. Furthermore, STING downregulation was inhibited by miR-24 anti-miRs and in Mirn23a locus-deficient macrophages. Failure to suppress STING expression in Mirn23a^-/- macrophages correlated with diminished Brucella replication, and was rescued by exogenous miR-24. Mirn23a-/- mice were also more resistant to splenic colonization one week post infection. Anti-miR-24 potently suppressed replication in wild type, but much less in STING^-/- macrophages, suggesting most of the impact of miR-24 induction on replication occurred via STING suppression. In summary, Brucella sabotages cytosolic surveillance by miR-24-dependent suppression of STING expression; post-STING activation “damage control” via targeted STING destruction may enable establishment of chronic infection.

Cytosolic pattern recognition receptors, such as the nucleotide-activated STING molecule, play a critical role in the innate immune system by detecting the presence of intracellular invaders. Brucella bacterial species establish chronic infections in macrophages despite initially activating STING. STING participates in the control of Brucella infection, as mice or cells lacking STING show a higher burden of Brucella infection. However, we have found that early following infection, Brucella upregulates a microRNA, miR-24, that targets the STING messenger RNA, resulting in lower STING levels. Dead bacteria or bacteria lacking a functional type IV secretion system were defective at upregulating miR-24 and STING suppression, suggesting an active bacteria-driven process. Failure to upregulate miR-24 and suppress STING greatly compromised the capacity of Brucella to replicate inside macrophages and in mice. Thus, although Brucella initially activate STING during infection, the ensuing STING downregulation serves as a “damage control” mechanism, enabling intracellular infection. Viruses have long been known to target immune sensors such as STING. Our results indicate that intracellular bacterial pathogens also directly target innate immune receptors to enhance their infectious success.

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.

Human brucellosis caused by raw dairy products: A review on the occurrence, major risk factors and prevention

Despite considerable efforts made to address the issue of brucellosis worldwide, its prevalence in dairy products remains difficult to estimate and represents an important public health issue in many areas of the globe today. This is partly explained by the increasing tendency for consumption of raw dairy products, making the prevention and control of this zoonosis even more critical. This review summarizes reports published since the early 2000s on human brucellosis caused by contaminated dairy products and the systems of evaluation and assessment which are used to improve the diagnosis, surveillance, control and prevention of the disease. For this purpose, five comprehensive electronic databases were investigated and relevant studies were identified for systematic review. The design and quality of the studies revealed notable variation, especially in the methods used for the detection and characterization of Brucella spp. This report provides helpful information about the health risk associated with the consumption of raw milk and relevant preventive strategies.