ELISA is superior to bacterial culture and agglutination test in the diagnosis of brucellosis in an endemic area in China

Advances in biosensors: A breakthrough in rapid and precise brucellosis detection

Brucellosis, a significant zoonotic disease, poses a threat to both livestock and human health. Infections in livestock lead to abortion, infertility, and substantial economic losses in the industry. In humans, acute brucellosis can progress to a chronic condition, resulting in multisystemic infections with high morbidity and mortality rates. Additionally, the bioterrorism potential of certain Brucella species through aerosol transmission poses risks to laboratory workers and livestock handlers. Therefore, there is an urgent need for rapid and precise diagnosis of brucellosis in both animals and humans. Even with the availability of routine diagnostic techniques that are effective they frequently have some limitations. Biosensors, as innovative techniques, have demonstrated significant potential in detecting various pathogens with high efficiency. These biosensors can identify specific analytes, biomolecules of pathogenic bacteria, secreted antibodies against bacteria, and even the bacterial body in real time. Their high sensitivity, selectivity, and user-friendly configurations make them valuable tools for diagnostics. In this comprehensive review, beside the reviewing routine diagnostic tests for detecting brucellosis and discussing the positive and negative aspects of these methods, we explore different types of biosensors and their applications in diagnosing brucellosis. We hope to show how these advancements can result in quicker and more precise disease detection by offering a thorough evaluation of these technologies performance and contrasting it with more conventional diagnostic techniques. This improves patient outcomes by lowering the complications linked to delayed diagnosis in addition to advancing scientific knowledge of brucellosis.

Establishment of an I-ELISA method based on multi-epitope fusion protein for diagnosis of human brucellosis

BACKGROUND

Brucellosis is a significant zoonotic disease that impacts people globally, and its diagnosis has long posed challenges. This study aimed to explore the application value of multi-epitope fusion protein in the diagnosis of human brucellosis.

METHODS

Eight important Brucella outer membrane proteins (OMPs) were selected: BP26, omp10, omp16, omp25, omp2a, omp2b, and omp31. Bioinformatics techniques were used to predict the immune epitopes of these proteins, and a multi-epitope fusion protein was designed. This fusion protein was used as the antigen for indirect enzyme-linked immunosorbent assay (iELISA) testing on 100 positive and 96 negative serum samples. The performance of the fusion protein in diagnosing brucellosis was evaluated using receiver operating characteristic (ROC) curves.

RESULTS

A total of 31 epitopes were predicted from the eight proteins, and a multi-epitope fusion protein was successfully obtained. For the detection of human serum samples, the area under the ROC curve (AUC) of the fusion protein was 0.9594, with a positive diagnostic accuracy of 91.26% and a negative diagnostic accuracy of 93.55%. The area under the ROC curve (AUC) for lipopolysaccharides (LPS) was 0.9999, with a positive diagnostic accuracy of 100% and a negative diagnostic accuracy of 98.97%.

CONCLUSIONS

The fusion protein constructed using bioinformatics techniques, as the diagnostic antigen, showed significantly reduced cross-reactivity and enhanced specificity, improving diagnostic accuracy. This not only saves time but also avoids the preparation of LPS antigens, making the diagnostic process safer and more convenient.

Case report: diagnosis of neurobrucellosis in a non-endemic area child using metagenomic next-generation sequencing

Brucellosis with neurological symptoms at onset is rare in children and is frequently misdiagnosed or overlooked due to nonspecific clinical presentations, particularly in non-endemic areas. We report a case of neurobrucellosis in a child from a non-pastoral area, diagnosed via metagenomic next-generation sequencing (mNGS). The patient presented with headache and altered consciousness, accompanied by fever, projectile vomiting, seizures, and urinary incontinence. Physical examination indicated possible nuchal rigidity. Cerebrospinal fluid (CSF) analysis showed colorless and clear fluid, with a white blood cell count of 259 × 10⁶/L, 4.6% polymorphonuclear cells, positive protein qualitative test, protein level of 0.78 g/L, and glucose level of 1.66 mmol/L. Initial diagnosis suggested central nervous system infection, and empirical treatment led to improvement in consciousness. However, after a few days of stable body temperature, the patient experienced recurrent fever. Ultimately, mNGS of CSF identified Brucella melitensis, confirming neurobrucellosis. Following treatment with ceftriaxone, doxycycline, and rifampin, the patient's clinical symptoms improved significantly, and follow-up CSF analysis showed normalization of cell counts. This case highlights the early diagnostic utility of mNGS in CSF for neurobrucellosis and its role in differential diagnosis.

True prevalence and spatial distribution of antibodies to Brucella spp. in goat populations in Hubei Province, People's Republic of China: Progress toward disease elimination

Caprine brucellosis, mainly caused by Brucella melitensis, remains a significant zoonotic threat worldwide, affecting animal productivity, welfare, and public health. This study aimed to estimate the true prevalence (TP) and spatial distribution of antibodies to Brucella spp. among goat populations in Hubei Province, China. In 2021, approximately 1.4 million serum samples were collected from 23,126 goat flocks across 82 counties of 16 municipal regions of Hubei Province. A combination of the Rose Bengal Test and Serum Agglutination Test in series was used to detect antibodies against Brucella spp. A hierarchical Bayesian Latent Class Model was used to account for imperfect diagnostic sensitivity and specificity of the tests, conditional dependence between the two tests, and hierarchical data structure to estimate the TP and the probability of achieving a 95 % probability of having a TP below 0.1 % for each county and municipal region. Apparent prevalence was 0.051 % and 0.536 % at the animal and flock level, respectively. The median animal level TP in the 82 counties was 0.0088 % (Range: 0.0008 %, 9.3730 %), with 76.8 % of counties showing a median TP estimate below 0.1 %. Counties containing positive goats were mainly clustered in Huanggang and Huangshi, and counties bordering positive counties had a higher risk of seropositivity. Notably, 52.4 % of counties achieved a 95 % probability with a TP below 0.1 %. Sensitivity analyses confirmed the robustness of these findings across prior distributions. It was concluded that Hubei Province has achieved remarkable progress in caprine brucellosis elimination programs, and priority interventions should be given to positive counties and their bordering counties.

Clinical characterization of brucellosis in children from non-pastoral areas: a report of five cases

BACKGROUND

Brucellosis is a global public health concern and occurs mainly in young adults and the elderly, with children having a lower incidence, thus often leading to delayed treatment. This study aimed to describe the epidemiologic features and clinical characteristics of brucellosis in children.

METHODS

In this retrospective study, the clinical data of five children diagnosed with brucellosis in Anhui Provincial Children's Hospital between January 1, 2021 and December 30, 2022 were analyzed.

RESULTS

All five cases were from non-pastoral areas, among which three have a history of livestock exposure and originated from the countryside. All patients had medium-high grade fever, mostly accompanied by night sweats and malaise, and three had joint pains. Laboratory tests showed that their white blood cell count was normal or mildly raised, with lymphocytes as the predominant cell population. Four patients had anemia, four had aspartate aminotransferase and alanine aminotransferase abnormality, and two had elevated ferritin levels. All blood samples were positive for Brucella culture, one of which had positive bone marrow culture, and all had positive serology test results. All patients were treated with rifampicin, in combination with sulfamethoxazole or doxycycline for 6 weeks following diagnosis. Four children had a good prognosis, but one child had recurrent joint pain.

CONCLUSIONS

The epidemiologic history of children from non-pastoral areas with brucellosis is often unclear; clinical manifestations and laboratory tests lack specificity; and they are easily delayed diagnosis. Clinicians should remain vigilant regarding the possibility of this disease in children with fever of unknown origin. The epidemiological history should be investigated in detail to improve the diagnostic ability of brucellosis. We recommend emphasizing serological testing. Children with brucellosis who receive timely diagnosis and standardized treatment can expect a favorable prognosis.

Seroprevalence of brucellosis among high-risk individuals in Madinah, Saudi Arabia

Background and Aim

Brucellosis is a highly contagious, neglected zoonotic disease of major importance worldwide. The disease is endemic in many countries, burdening healthcare systems and the livestock industry and representing a persistent public health concern in these countries. Brucellosis is considered an important occupational hazard for livestock workers. Limited studies have investigated human brucellosis in Saudi Arabia. Therefore, this study aimed to estimate the prevalence of brucellosis among employees of high-risk brucellosis professions, including veterinarians, animal herders, and abattoir workers in Madinah, Saudi Arabia, and to determine the associated risk factors.

Materials and Methods

A cross-sectional study was conducted in Madinah, Saudi Arabia, during the period of January-March 2023. Ninety blood samples were collected from individuals occupationally at risk of exposure to Brucella infections. Serum samples were examined for immunoglobulins (Ig)M and IgG antibodies against Brucella using an indirect enzyme-linked immunosorbent assay. Before sample collection, a predesigned online questionnaire was used to collect the participants' sociodemographic characteristics and the probable risk factors for human brucellosis. A Chi-square test was used to compare the differences among groups; p < 0.05 were considered statistically significant.

Results

Among the 90 participants among the high-risk individuals, Brucella IgM and IgG seropositivity were found in 8 (8.8%) and 11 (12.12%) cases, respectively. IgM mono antibody positivity was observed in 4 (4.44%) and 7 (7.77%) of the study population who tested positive for IgG only. Dual positivity for IgM and IgG antibodies was observed in 4 (4.44%) participants. No significant association was determined between seropositivity and age, urbanicity, education, occupation, and duration of exposure (p > 0.05).

Conclusion

Brucellosis is a high-risk occupational disease among workers with close contact with livestock. This study demonstrates that the seroprevalence of brucellosis among occupationally high-risk individuals in Madinah, Saudi Arabia, is relatively low compared to other countries in the region. Nevertheless, educational programs should be implemented to improve knowledge regarding brucellosis, particularly among high-risk individuals.

Determining Diagnostic Sensitivity: A Comparison of Rose Bengal Test, Coombs Gel Test, ELISA and Bacterial Culture in Brucellosis Diagnosis-Analyzing Clinical Effectiveness in Light of Inflammatory Markers

BACKGROUND

Brucellosis is a zoonotic infectious disease. It is estimated that the number of cases reported today is much less than the actual number. We still have difficulty in diagnosing the disease and its organ involvement. In this sense, new approaches that can be useful in clinical practice are required, and we aimed to evaluate this situation in our study.

METHODS

171 of 213 patients followed in our center between January 2021 and April 2024 were included in the study. A total of 150 patients were included in the study as a control group. Rose Bengal test (RBT), Coombs gel test (CGT), enzyme-linked immunosorbent assay (ELISA), and automated blood culture were used for diagnosing brucellosis. Complete blood count, sedimentation, C-reactive protein, and biochemical parameters were obtained. Inflammation markers such as neutrophil-lymphocyte ratio, platelet-lymphocyte ratio, systemic immune-inflammation index, and systemic inflammation response index were calculated.

RESULTS

The most successful results in the diagnosis were ELISA (89.4%), RBT (88.3%), CGT (83%), and blood culture (34.8%). For diagnosing sacroiliitis and spondylodiscitis, instead of resorting to expensive methods like magnetic resonance, a combination of ELISA positivity with elevated acute phase reactants and inflammatory markers could be significantly instructive.

CONCLUSIONS

Optimizing diagnostic algorithms and exploring novel diagnostic approaches, such as inflammatory markers, hold promise for improving diagnosis and management.

Probing the expression and adhesion of glycans involved in Helicobacter pylori infection

Helicobacter pylori infects approximately half the human population and has an unusual infective niche of the human stomach. Helicobacter pylori is a major cause of gastritis and has been classified as a group 1 carcinogen by the WHO. Treatment involves triple or quadruple antibiotic therapy, but antibiotic resistance is becoming increasingly prevalent. Helicobacter pylori expresses certain blood group related antigens (Lewis system) as a part of its lipopolysaccharide (LPS), which is thought to assist in immune evasion. Additionally, H. pylori LPS participates in adhesion to host cells alongside several adhesion proteins. This study profiled the carbohydrates of H. pylori reference strains (SS1 and 26695) using monoclonal antibodies (mAbs) and lectins, identifying interactions between two carbohydrate-targeting mAbs and multiple lectins. Atomic force microscopy (AFM) scans were used to probe lectin and antibody interactions with the bacterial surfaces. The selected mAb and lectins displayed an increased adhesive force over the surface of the curved H. pylori rods. Furthermore, this study demonstrates the ability of anti-carbohydrate antibodies to reduce the adhesion of H. pylori 26695 to human gastric adenocarcinoma cells via AFM. Targeting bacterial carbohydrates to disrupt crucial adhesion and immune evasion mechanisms represents a promising strategy for combating H. pylori infection.

Guanidinium-Functionalized Polymer Dielectrics for Triboelectric Bacterial Detection

Development of rapid detection strategies that target potentially pathogenic bacteria has gained increasing attention due to the increasing awareness for better health and safety. In this study, we evaluate an intrinsically antimicrobial polymer, 2Gdm, which is a poly(norbornene)-based functional polymer featuring guanidinium groups as side chains, for bacterial detection by the means of triboelectric nanogenerators (TENGs) and triboelectric nanosensors (TENSs). Attachment of bacteria to the sensing layer is anticipated to alter the overall triboelectric properties of the underlying polymer layer. The positively charged guanidinium functional groups can interact with the negatively charged phospholipid bilayer of bacteria and lead to bacterial death, which can then be detected by optical microscopy, X-ray photoelectron microscopy, and more advanced self-powered sensing techniques such as TENGs and TENSs. The double bonds present along the poly(norbornene) backbone allow for thermally induced cross-linking to obtain X-2Gdm and thus rendering materials remain stable in water. By monitoring the change in voltage output after immersion in various concentrations of Gram-negative Escherichia coli (E. coli) and Gram-positive Streptococcus pneumoniae (S. pneumoniae), we have demonstrated the utility of X-2Gdm as a new polymer dielectric for autonomous bacterial detection. As the bacterial concentration increases, the amount of adsorbed bacteria also increases, resulting in a decrease in the surface potential of the X-2Gdm thin film; this reduction in surface potential can cause a decrease in the triboelectric output for both TENGs and TENSs, which serves as a key working mechanism for facile bacterial detection. TENG and TENS systems are capable of detecting E. coli and S. pneumoniae within a range of 4 × 105 to 4 × 108 CFU/mL with a limit of detection of 106 CFU/mL. This report highlights the promising prospects of employing TENGs and TENSs as innovative sensing technologies for rapid bacterial detection by leveraging the electrostatic interactions between bacterial cell membranes and cationic groups present on polymer surfaces.

DNA Sensor for the Detection of Brucella spp. Based on Magnetic Nanoparticle Markers

Due to the limitations of conventional Brucella detection methods, including safety concerns, long incubation times, and limited specificity, the development of a rapid, selective, and accurate technique for the early detection of Brucella in livestock animals is crucial to prevent the spread of the associated disease. In the present study, we introduce a magnetic nanoparticle marker-based biosensor using frequency mixing magnetic detection for point-of-care testing and quantification of Brucella DNA. Superparamagnetic nanoparticles were used as magnetically measured markers to selectively detect the target DNA hybridized with its complementary capture probes immobilized on a porous polyethylene filter. Experimental conditions like density and length of the probes, hybridization time and temperature, and magnetic binding specificity, sensitivity, and detection limit were investigated and optimized. Our sensor demonstrated a relatively fast detection time of approximately 10 min, with a detection limit of 55 copies (0.09 fM) when tested using DNA amplified from Brucella genetic material. In addition, the detection specificity was examined using gDNA from Brucella and other zoonotic bacteria that may coexist in the same niche, confirming the method's selectivity for Brucella DNA. Our proposed biosensor has the potential to be used for the early detection of Brucella bacteria in the field and can contribute to disease control measures.

Laboratory diagnostics for primary spinal infections in pediatric and adult populations: a narrative review

Primary spinal infection (PSI) is a generic term covering a heterogeneous group of infections that can affect the vertebral body, intervertebral disks, the content of the medullary cavity, and adjacent paraspinal tissues. Patients' characteristics can vary significantly, notably according to their age, and some of these characteristics undoubtedly play a primordial role in the occurrence of a PSI and in the type of offending pathogen. Before approaching the subject of laboratory diagnostics, it is essential to define the characteristics of the patient and their infection, which can then guide the physician toward specific diagnostic approaches. This review critically examined the roles and usefulness of traditional and modern laboratory diagnostics in supporting clinicians' decision-making in cases of pediatric and adult primary spinal infection (PSI). It appears impossible to compare PSIs in children and adults, whether from an epidemiological, clinical, bacteriological, or biological perspective. The recipients are really too different, and the responsible germs are closely correlated to their age. Secondly, the interpretation of traditional laboratory blood tests appears to contribute little guidance for clinicians attempting to diagnose a PSI. Biopsy or needle aspiration for bacterial identification remains a controversial subject, as the success rates of these procedures for identifying causative organisms are relatively uncertain in pediatric populations.Using nucleic acid amplification assays (NAAAs) on biopsy samples has been demonstrated to be more sensitive than conventional cultures for diagnosing PSI. Recent advances in next-generation sequencing (NGS) are particularly interesting for establishing a microbiological diagnosis of a PSI when standard cultures and NAAAs have failed to detect the culprit. We can even imagine that plasma metagenomic NGS using plasma (known as "liquid biopsy") is a diagnostic approach that can detect not only pathogens circulating in the bloodstream but also those causing focal infections, and thus eliminate the need for source sample collection using costly invasive surgical procedures.

Immunoassay-based evaluation of rOmp28 protein as a candidate for the identification of Brucella species

Introduction. Brucellosis is an important bacterial zoonosis, re-emerging as a serious public health concern in developing countries. Two major species, Brucella melitensis and Brucella abortus, cause recurrent facile infection in human. Therefore, rapid and accurate diagnosis for early disease control and prevention is needed in areas with low disease burden.Hypothesis. This study evaluated the sandwich enzyme-linked immunosorbent assay (ELISA) (S-ELISA) immunoassay for potential use of whole-cell (WC) and recombinant outer-membrane protein (rOmp28)-derived IgG polyclonals in sensitive detection of Brucella.Aim. Immunoassay-based WC detection of Brucella species in important sub-clinical matrices at lower limits of detection.Methodology. We purified recombinant rOmp28 with Ni-NTA gel affinity chromatography and produced IgG polyclonal antibodies (pAbs) using BALB/c mice and New Zealand white female rabbits against different antigens (Ags) of Brucella. Checkerboard sandwich ELISA and P/N ratio (optical density of 'P' positive test sample to 'N' negative control) were used for evaluation and optimization of the study. The pAbs were characterized using Western blot analysis and different matrices were spiked with WC Ag of Brucella.Results. Double-antibody S-ELISA was developed using WC Ag-derived rabbit IgG (capture antibody at 10 µg ml^-1) and rOmp28-derived mice IgG (detection antibody at 100 µg ml^-1) with a detection range of 10² to 10⁸ cells ml^-1 and a limit of detection at 10² cells ml^-1. A P/N ratio of 1.1 was obtained with WC pAbs as compared to 0.6 and 0.9 ratios with rOmp28-derived pAbs for detecting B. melitensis 16M and B. abortus S99, respectively. An increased P/N ratio of 4.4 was obtained with WC Ag-derived rabbit IgG as compared to 4.2>4.1>2.4 ratios obtained with rabbit IgGs derived against cell envelope (CE), rOmp28 and sonicated antigen (SA) of Brucella with high affinity for rOmp28 Ag analysed on immunoblots. The rOmp28-derived mice IgG revealed two Brucella species at P/N ratios of 11.8 and 6.3, respectively. Upon validation, S-ELISA detected Brucella WCs in human whole blood and sera samples with no cross-reactivity to other related bacteria.Conclusion. The developed S-ELISA is specific and sensitive in early detection of Brucella from different matrices of clinical and non-clinical disease presentation.

Rapid discrimination of Brucellosis in sheep using serum Fourier transform infrared spectroscopy combined with PCA-LDA algorithm

Brucellosis in sheep is an infectious disease caused by Brucella melitensis in sheep. The current conventional serological methods for screening Brucella-infected sheep have the disadvantage of time consuming and low accuracy, so a simple, rapid and highly accurate screening method is needed. The aim of this study was to evaluate the feasibility of diagnosing Brucella-infected sheep by serum samples based on the Fourier transform infrared (FTIR) spectroscopy. In this study, FTIR spectroscopy of serum from Brucella-infected sheep (n=102) and healthy sheep (n=125) revealed abnormal protein and lipid metabolism in serum from Brucella-infected sheep compared to healthy sheep. Principal component analysis-Linear discriminant analysis (PCA-LDA) method was used to differentiate the FTIR spectra of serum from Brucella-infected sheep and healthy sheep in the protein band (3700-3090 cm^-1) and lipid band (3000-2800 cm^-1), and its overall diagnostic accuracy was 100% (sensitivity 100%, specificity 100%). In conclusion, our results suggest that serum FTIR spectroscopy combined with PCA-LDA algorithm has great potential for brucellosis in sheep screening.

A Case Report of Brucellosis-Associated Infective Endocarditis

Brucellosis is a prevalent zoonotic infection that can be relatively well managed and tolerated if appropriate treatment is initiated. Unfortunately, likely secondary to decreased awareness and vague symptoms, the diagnosis can be easily missed leading to worsening complications that severely increase the mortality rate. We present a case of a 25-year-old female who presented from a rural setting with a diagnosis of brucellosis, which was delayed. She ultimately developed infective endocarditis with cardiac vegetations on imaging. Despite improvement on antibiotics and reduction in size of cardiac vegetation, she suffered a fatal cardiac arrest before undergoing surgical intervention. Better awareness regarding hygiene and sanitary food handling should be encouraged, especially in underdeveloped rural areas, to help prevent infection. More studies need to be performed to help better identify symptoms coupled with maintaining a high index of suspicion so as to expedite diagnosis, treatment, management and hopefully prevent the progression of disease and worsening complications.

A rapid direct-differential agglutination assay for Brucella detection using antibodies conjugated with functionalized gold nanoparticles

Brucellosis is the most widespread and serious zoonotic disease worldwide which affects livestock, sylvatic wildlife, marine dwellers, and humans. It is acquired through Alphaproteobacteria which belong to the genus Brucella and is categorized as a potential bio-threat agent. In this study, we developed a rapid and direct differential whole cell (WC) agglutination-based assay for its on-field detection. The recombinant outer membrane (rOmp28) protein-derived specific mice IgG polyclonal antibodies (pAbs) of Brucella were purified using affinity chromatography and conjugated with functionalized gold nanoparticles (AuNPs) for rapid agglutination. A positive blot of 32 kDa protein revealed specific immuno-reactivity of rOmp28-pAbs using immunoblot analysis. For the synthesis of AuNPs, the conventional “Turkevich method” was optimized at a concentration &lt; 1 mM of gold precursor for obtaining 50-nm-sized particles. Also, their physico-chemical characteristics were analyzed using UV-visible spectrophotometry, Fourier transform infra-red spectroscopy (FT-IR), Raman spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), dynamic light scattering (DLS), zeta potential (ζ, ZP), and fluorescence spectroscopy. Furthermore, these AuNPs were functionalized with N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS) to prepare modified carboxylated AuNPs. For bioconjugation with Brucella rOmp28 IgG pAbs, antibody-conjugated functionalized AuNP constructs were prepared and characterized using FT-IR analysis with strong N–H deformations. Subsequently, these bioconjugated AuNPs were used to develop a direct-differential slide agglutination assay with a detection limit of 104 CFU mL−1. The sensitivity of this assay was compared with standard double-antibody sandwich ELISA (S-ELISA) using rOmp28 IgG pAbs with an LOD of 103 CFU mL−1 and a detection range of 102–108 CFU mL−1. No intraspecies cross-reactivity was observed based on evaluation of its specificity with a battery of closely related bacterial species. In conclusion, the increased sensitivity and specificity of the developed agglutination assay obtained using bioconjugated functionalized AuNPs is ≥ 98% for the detection of Brucella. Therefore, it can be used as an alternate rapid method of direct WC detection of bacteria as it is simple, robust, and cost-effective, with minimal time of reaction in the case of early disease diagnosis.

Evaluation of serological diagnostic tests for bovine brucellosis in dairy cattle herds in an endemic area: a multicenter study

Brucellosis is known as one of the most common zoonotic diseases worldwide affecting both livestock and humans. It causes abortions, reduces milk production, and infertility in infected animals. The disease is routinely diagnosed through three serological techniques, such as rose bengal plate test (RBPT), standard agglutination test (SAT), and indirect enzyme-linked immunosorbent assay (I-ELISA). The aim of this study was to identify and compare the brucellosis seroprevalence among dairy cattle farms through these different serological tests. From 2112 sampled dairy cattle in different parts of Iran, RBPT, SAT, and I-ELISA led to 296 (14.02%), 215 (10.18%), and 297 (14.06%) positive results, respectively. Brucella abortus biovar 3 (62 cases) was identified as the most common cause of brucellosis in tested animals. Our results showed that the specificity and sensitivity of I-ELISA were higher than those obtained by RBPT and SAT. In this study, the overall agreement of RBPT and SAT with I-ELISA reached 95.21% and 94.12% in dairy cattle farms, respectively. Furthermore, Cohen's kappa statistical analysis revealed that the best degree of agreement was seen between RBPT and I-ELISA (0.80), followed by RBPT and SAT (0.78) and finally SAT and I-ELISA (0.72), thereby indicating a strong agreement between RBPT and I-ELISA methods and good agreement between SAT and I-ELISA methods. The McNemar analysis also showed that a significant difference exists between positive and negative results determined by SAT and I-ELISA methods (p < 0.0001). However, the positive and negative results determined by I-ELISA and RBPT did not show a significant difference (p = 0.9207). Therefore, I-ELISA was a more specific and sensitive serological test when compared to RBPT and SAT and could remarkably decrease non-specific reaction by improving the serological screening specificity for an accurate brucellosis diagnosis in endemic areas.

Evaluating the efficacy of serological testing of clinical specimens collected from patients with suspected brucellosis

BACKGROUND

This study aims to evaluate the efficacy of the standard agglutination test (SAT), the Brucellacapt test and enzyme-linked immunosorbent assay (ELISA) in clinical specimens collected from patients with suspected brucellosis.

METHODS

A prospective study was conducted from December 2020 to December 2021. Brucellosis was diagnosed on the basis of clinical evidence, and confirmed by isolation of Brucella or a four-fold rise in SAT titer. All samples were tested by the SAT, ELISA and the Brucellacapt test. Titers ≥1:100 were considered as SAT positive; ELISA was considered positive when an index greater than 11 was detected, while titers ≥1/160 indicated positivity on the Brucellacapt test. The specificity, sensitivity, and positive (PPVs) and negative predictive values (NPVs) of the three different methods were calculated.

RESULTS

A total of 149 samples were collected from patients with suspected brucellosis. The sensitivities for the SAT, IgG, and IgM detection were 74.42%, 88.37% and 74.42%, respectively. The specificities were 95.24%, 93.65%, and 88.89%, respectively. The simultaneous measurement of IgG and IgM improved the sensitivity (98.84%) but reduced the specificity (84.13%) compared to each antibody test separately. The Brucellacapt test had excellent specificity (100%) and a high PPV (100%); however, the sensitivity and NPV were 88.37% and 86.30%, respectively. The combination of IgG detection by ELISA and the Brucellacapt test had excellent diagnostic performance, with 98.84% sensitivity and 93.65% specificity.

CONCLUSION

This study showed that the simultaneous performance of IgG detection by ELISA and the Brucellacapt test has the potential to overcome the current limitations of detection.

Femoral Head Necrosis Due to Brucella Infection in China: Case Series and Literature Review

Introduction

The causes of femoral head necrosis mainly include trauma, corticosteroid, and alcohol, among which Brucella is highly unusual.

Patients and Methods

This paper reported three rare cases of femoral head necrosis due to Brucella, summarizing and analyzing the epidemiological history, clinical manifestations, laboratory examinations, imaging findings, individualized therapy, and biopsy results of patients with this disease. A literature review related to brucellosis and femoral head necrosis was conducted.

Results

All three patients had an epidemic history of brucellosis. They suffered from hip pain and limitation of movement for months, and femoral head necrosis was confirmed by magnetic resonance imaging (MRI). Pathological Giemsa staining or real-time polymerase chain reaction (real-time PCR) confirmed Brucella melitensis (B. melitensis) as the cause of osteonecrosis. Each patient received individualized therapy according to the degree of osteonecrosis, which was based on anti-brucellosis medications and hip puncture and irrigation decompression. They were followed up for more than two years and rehabilitated well.

Conclusion

Brucella infection should always be considered the cause of femoral head necrosis for patients with hip pain, especially for those with an epidemic history; early diagnosis and individual stepwise therapy can prevent the progression of osteonecrosis.

Beware of Brucella Spondylitis Following Vertebroplasty: An Unusual Case of Osteoporotic Vertebral Compression Fracture

There are two main types of infectious spondylitis reported in literature following kyphoplasty or vertebroplasty: tuberculous spondylitis and pyogenic spondylitis; no cases of Brucella spondylitis have been reported to date. We present a unique case of Brucella spondylitis with intraspinal abscess following vertebroplasty. The patient suffered from osteoporotic vertebral compression fracture (OVCF) of the L4 vertebra and received vertebroplasty; he ate mutton while traveling in the epidemic area a week before vertebroplasty. Two weeks after the procedure, the patient had recurrent low back pain and was finally diagnosed with Brucella spondylitis around the L4 vertebra four months later. This case report provides a warning that eating any undercooked food that may cause bacteremia—especially in orthopedic patients with joint or osseous abnormalities and especially those with intraosseous devices or injected substances.

A Label-Based Polymer Nanoparticles Biosensor Combined with Loop-Mediated Isothermal Amplification for Rapid, Sensitive, and Highly Specific Identification of Brucella abortus

Brucella abortus (B. abortus), an important zoonotic pathogen in Brucella spp., is the major causative agent of abortion in cattle (namely, bovine brucellosis). Currently, although the isolation and identification of the Brucella abortus were commonly accepted as the gold standard method, it cannot meet the requirements for early diagnostic strategies. Conventional PCR techniques and immunological tests can realize rapid detection of B. abortus, but the demands for PCR thermal cyclers and/or specific antibodies hinder their application in basic laboratories. Thus, rapid, sensitive, and specific diagnostic strategies are essential to prevent and control the spread of the bovine brucellosis. In this work, a novel detection method for the rapid identification of B. abortus, which uses loop-mediated isothermal amplification (LAMP) combined with a label-based polymer nanoparticles lateral flow immunoassay biosensor (LFIA), was established. One set of specific B. abortus-LAMP primers targeting the BruAb2_0168 gene was designed by the online LAMP primer design tool. The B. abortus-LAMP-LFIA assay was optimized and evaluated using various pathogens and whole blood samples. The optimal amplification temperature and time for B. abortus-LAMP-LFIA were determined to be 65°C and 50 min, respectively. The B. abortus-LAMP-LFIA method limit of detection (LoD) was 100 fg per reaction for pure genomic DNA of B. abortus. Meanwhile, the detection specificity was 100%, and there was no cross-reactivity for other Brucella members and non-Brucella strains. Furthermore, the entire procedure, including the DNA preparation for whole blood samples (30 min), isothermal incubation (50 min), and LFIA detection (2–5 min), can be completed in approximately 85 min. Thus, the B. abortus-LAMP-LFIA assay developed was a simple, rapid, sensitive, and reliable detection technique, which can be used as a screening and/or diagnostic tool for B. abortus in the field and basic laboratories.

A Multi-Epitope Fusion Protein-Based p-ELISA Method for Diagnosing Bovine and Goat Brucellosis

In recent years, the incidence of brucellosis has increased annually, causing tremendous economic losses to animal husbandry in a lot of countries. Therefore, developing rapid, sensitive, and specific diagnostic techniques is critical to control the spread of brucellosis. In this study, bioinformatics technology was used to predict the B cell epitopes of the main outer membrane proteins of Brucella, and the diagnostic efficacy of each epitope was verified by an indirect enzyme-linked immunosorbent assay (iELISA). Then, a fusion protein containing 22 verified epitopes was prokaryotically expressed and used as an antigen in paper-based ELISA (p-ELISA) for serodiagnosis of brucellosis. The multi-epitope-based p-ELISA was evaluated using a collection of brucellosis-positive and -negative sera collected from bovine and goat, respectively. Receiver operating characteristic (ROC) curve analysis showed that the sensitivity and specificity of detection-ELISA in diagnosing goat brucellosis were 98.85 and 98.51%. The positive and the negative predictive values were 99.29 and 98.15%, respectively. In diagnosing bovine brucellosis, the sensitivity and specificity of this method were 97.85 and 96.61%, with the positive and negative predictive values being identified as 98.28 and 97.33%, respectively. This study demonstrated that the B cell epitopes contained in major antigenic proteins of Brucella can be a very useful antigen source in developing a highly sensitive and specific method for serodiagnosis of brucellosis.

Applications of Raman Spectroscopy in Bacterial Infections: Principles, Advantages, and Shortcomings

Infectious diseases caused by bacterial pathogens are important public issues. In addition, due to the overuse of antibiotics, many multidrug-resistant bacterial pathogens have been widely encountered in clinical settings. Thus, the fast identification of bacteria pathogens and profiling of antibiotic resistance could greatly facilitate the precise treatment strategy of infectious diseases. So far, many conventional and molecular methods, both manual or automatized, have been developed for in vitro diagnostics, which have been proven to be accurate, reliable, and time efficient. Although Raman spectroscopy (RS) is an established technique in various fields such as geochemistry and material science, it is still considered as an emerging tool in research and diagnosis of infectious diseases. Based on current studies, it is too early to claim that RS may provide practical guidelines for microbiologists and clinicians because there is still a gap between basic research and clinical implementation. However, due to the promising prospects of label-free detection and noninvasive identification of bacterial infections and antibiotic resistance in several single steps, it is necessary to have an overview of the technique in terms of its strong points and shortcomings. Thus, in this review, we went through recent studies of RS in the field of infectious diseases, highlighting the application potentials of the technique and also current challenges that prevent its real-world applications.

Comparison of loop-mediated isothermal amplification and conventional PCR tests for diagnosis of common Brucella species

OBJECTIVE

Rapid, reliable, and affordable detection of Brucella species via the molecular methods remains a challenge. In recent years, loop-mediated isothermal amplification (LAMP) is a functional nucleic acid amplification technique offering a substitute to polymerase chain reaction (PCR). So, we compared the LAMP assay with the conventional PCR for the identification of common Brucella species in Iran. In this study, LAMP assay was comprehensively evaluated against the common PCR method. A group of specific LAMP primers were used to amplify a highly specific fragment from the sequence of the Brucella abortus, bcsp31 gene. Sensitivity and specificity values of tests were done with a set of 78 (50 Brucella and 28 non-Brucella) strains.

RESULTS

A dilution series of B. abortus DNA indicated that the LAMP reaction could reliably detect 10 (fg/µl) DNA target copies per reaction within 36 min, which is 10 times greater than the PCR assay. In summary, we conclude that LAMP assay provide accurate and fast test results to identify of common Brucella species in low-complexity labs, mainly in low and lower middle income countries.

Immunological pathways of macrophage response to Brucella ovis infection

As the molecular mechanisms of Brucella ovis pathogenicity are not completely clear, we have applied a transcriptome approach to identify the differentially expressed genes (DEGs) in RAW264.7 macrophage infected with B. ovis. The DEGs related to immune pathway were identified by Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) functional enrichment analysis. Quantitative real-time PCR (qRT-PCR) was performed to validate the transcriptome sequencing data. In total, we identified 337 up-regulated and 264 down-regulated DEGs in B. ovis-infected group versus mock group. Top 20 pathways were enriched by KEGG analysis and 20 GO by functional enrichment analysis in DEGs involved in the molecular function, cellular component, and biological process and so on, which revealed multiple immunological pathways in RAW264.7 macrophage cells in response to B. ovis infection, including inflammatory response, immune system process, immune response, cytokine activity, chemotaxis, chemokine-mediated signaling pathway, chemokine activity, and CCR chemokine receptor binding. qRT-PCR results showed Ccl2 (ENSMUST00000000193), Ccl2 (ENSMUST00000124479), Ccl3 (ENSMUST00000001008), Hmox1 (ENSMUST00000005548), Hmox1 (ENSMUST00000159631), Cxcl2 (ENSMUST00000075433), Cxcl2 (ENSMUST00000200681), Cxcl2 (ENSMUST00000200919), and Cxcl2 (ENSMUST00000202317). Our findings firstly elucidate the pathways involved in B. ovis-induced host immune response, which may lay the foundation for revealing the bacteria–host interaction and demonstrating the pathogenic mechanism of B. ovis.

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.