[Brucellosis in the 21st Century]

Brucella infection following total joint arthroplasty: A systematic review of the literature

INTRODUCTION

The aim of this systematic review was to analyze the results of published treatment options in Brucella infection following total joint arthroplasty (TJA).

METHODS

We performed a systematic review of the literature regarding outcomes of Brucella infection after TJA (hip and knee). We searched multiple databases for articles in the area published from 1950 to 2016.

RESULTS

A total of 18 patients (12 male and 6 female; mean age 59 years) from 14 published studies were identified. The minimum follow-up time was 6 months (range, 6-120 months). Seven patients were treated with debridement or antibrucella treatment only. Eleven patients (61%) underwent removal of the prosthesis and were treated with one or two-stage exchange arthroplasty. The mean duration of antibiotic therapy was 5.8 months. There was no relapse of infection.

CONCLUSIONS

In the absence of loosening of the components of the prosthesis, an attempt to treat Brucella infection medically might be a reasonable choice. One or two-stage exchange arthroplasty could provide successful results without relapse of infection when combined with appropriate antibiotherapy.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Comparative clinical study of different multiplex real time PCR strategies for the simultaneous differential diagnosis between extrapulmonary tuberculosis and focal complications of brucellosis

BACKGROUND

Both brucellosis and tuberculosis are chronic-debilitating systemic granulomatous diseases with a high incidence in many countries in Africa, Central and South America, the Middle East and the Indian subcontinent. Certain focal complications of brucellosis and extrapulmonary tuberculosis are very difficult to differentiate clinically, biologically and radiologically. As the conventional microbiological methods for the diagnosis of the two diseases have many limitations, as well as being time-consuming, multiplex real time PCR (M RT-PCR) could be a promising and practical approach to hasten the differential diagnosis and improve prognosis.

METHODOLOGY/PRINCIPAL FINDINGS

We designed a SYBR Green single-tube multiplex real-time PCR protocol targeting bcsp31 and the IS711 sequence detecting all pathogenic species and biovars of Brucella genus, the IS6110 sequence detecting Mycobacterium genus, and the intergenic region senX3-regX3 specifically detecting Mycobacterium tuberculosis complex. The diagnostic yield of the M RT-PCR with the three pairs of resultant amplicons was then analyzed in 91 clinical samples corresponding to 30 patients with focal complications of brucellosis, 24 patients with extrapulmonary tuberculosis, and 36 patients (Control Group) with different infectious, autoimmune or neoplastic diseases. Thirty-five patients had vertebral osteomyelitis, 21 subacute or chronic meningitis or meningoencephalitis, 13 liver or splenic abscess, eight orchiepididymitis, seven subacute or chronic arthritis, and the remaining seven samples were from different locations. Of the three pairs of amplicons (senX3-regX3+ bcsp3, senX3-regX3+ IS711 and IS6110+ IS711) only senX3-regX3+ IS711 was 100% specific for both the Brucella genus and M. tuberculosis complex. For all the clinical samples studied, the overall sensitivity, specificity, and positive and negative predictive values of the M RT-PCR assay were 89.1%, 100%, 85.7% and 100%, respectively, with an accuracy of 93.4%, (95% CI, 88.3-96.5%).

CONCLUSIONS/SIGNIFICANCE

In this study, a M RT-PCR strategy with species-specific primers based on senX3-regX3+IS711 sequences proved to be a sensitive and specific test, useful for the highly efficient detection of M. tuberculosis and Brucella spp in very different clinical samples. It thus represents an advance in the differential diagnosis between some forms of extrapulmonary tuberculosis and focal complications of brucellosis.

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.

Usefulness of a quantitative real-time PCR assay using serum samples to discriminate between inactive, serologically positive and active human brucellosis

Diagnosis of brucellosis can be difficult in certain scenarios where conventional microbiological techniques have important limitations. The aim of this study was to develop a LightCycler Quantitative PCR assay in serum samples to discriminate between active and past brucellosis. In total, 110 serum samples from 46 brucellosis patients and 64 controls, including persons who had recently been treated for brucellosis, asymptomatic persons exposed to brucellosis, and patients with febrile syndromes involving a differential diagnosis with brucellosis, were studied. Brucella spp.-specific sequences of the PCR primers and probe were selected from the gene encoding an immunogenic membrane protein of 31 kDa (BCSP31). The analytical sensitivity was 1 x 10(1) fg of Brucella DNA. The mean threshold cycles for brucellosis patients and controls were 31.8 +/- 1.7 and 35.4 +/- 1.1, respectively (p <0.001). The best cut-off for bacterial DNA load was 5 x 10(3) copies/mL. At this cut-off, the area under the receiver operating characteristic curves was 0.963 (95% CI 0.920-1.005), with a sensitivity of 93.5% and a specificity of 98.4%. Under the assay conditions, the LightCycler Quantitative PCR in serum samples seems to be highly reproducible, rapid, sensitive and specific. It is therefore a useful method for both the initial diagnosis and the differentiation between past and active brucellosis.

Perspectives for the treatment of brucellosis in the 21st century: the Ioannina recommendations

The authors provide evidence-based guidance on treating human brucellosis, and discuss the future clinical trials that would help address the controversies surrounding treatment.

Polymorphism of the transmembrane region of the MICA gene and human brucellosis

We investigated the polymorphism of the transmembrane region of the MICA gene (major histocompatibility complex class I chain-related gene A) in relation to susceptibility to human brucellosis. We typed 114 patients with brucellosis and 121 healthy controls for MICA transmembrane polymorphism with polymerase chain reaction methods combined with fluorescent technology. We found a significant decrease in the frequency of the MICA-A4 allele in the patients with brucellosis compared with the controls (4.4% vs 10.3%, Pc = 0.03). The frequency of the MICA-A5 allele was increased in the group of patients with focal complications (15% vs 38%, Pc = 0.004). Our data suggest the MICA-A4 allele shows a tendency to be protective against infection by Brucella melitensis. Furthermore, the MICA-A5 allele appears to confer susceptibility to focal forms in patients with brucellosis.

Total hip arthroplasty infected by Brucella: a report of two cases

Infection caused by Brucella following total joint arthroplasty is very rare. We present 2 cases of brucellar infection following total hip arthroplasty (THA). A 66-year-old woman who had prolonged contact with cattle presented with pain at the thigh and groin areas. The patient had undergone an uncemented THA for a hip fracture 3 years previously. Cultures of articular liquid were positive for Brucella abortus. The implant was loosened and was managed with a 2-stage re-implantation. A 71-year-old man presented with painless suppuration of the hip joint through the scar from previous surgeries. Radiography demonstrated a well-integrated THA. When postoperative cultures were found positive for Brucella melitensis, antibiotic treatment of rifampicin 900 mg, streptomycin 1 g, and doxycycline 200 mg daily were prescribed. At 5.5-year and 5-year follow-up, respectively, both patients were asymptomatic and free of infection with well-integrated implants. As the Brucella pathogen is highly susceptible to antibiotics, standard 2-stage revision arthroplasty for loosened implant or debridement and antibiotic treatment for well-fixed implant should suffice.

Variation in the NRAMP1 gene does not affect susceptibility or protection in human brucellosis

Genetic susceptibility to human brucellosis has so far been localized to variants of genes, which participate in the specific response and the innate immune response. The Nramp1 gene, which participates in the innate response, is related to susceptibility and protection in bovine brucellosis. We examined the polymorphism of the human NRAMP1 gene in 65 patients with brucellosis and 89 healthy controls and found no significant differences in the alleles studied. Thus, variants of the NRAMP1 gene do not appear to affect susceptibility or protection in human brucellosis.

Comparison between LightCycler Real-Time Polymerase Chain Reaction (PCR) Assay with Serum and PCR-Enzyme-Linked Immunosorbent Assay with Whole Blood Samples for the Diagnosis of Human Brucellosis

BACKGROUND

To overcome some of the limitations of conventional microbiological techniques, polymerase chain reaction (PCR)-based assays have been proposed as a useful tool for the diagnosis of human brucellosis.

METHODS

A single-blinded comparative study was undertaken that compared 2 different PCR assays: a SYBR Green I LightCycler-based Real-Time PCR assay (LC-PCR; Roche Diagnostic) with serum samples and a PCR-enzyme-linked immunosorbent assay (ELISA) with whole blood samples. Both assays amplify a 223-bp sequence of a gene that codes for the synthesis of an immunogenetic membrane protein specific for Brucella genus (BCSP31). We analyzed the diagnostic yield of these assays with 60 samples obtained from patients with active brucellosis and 37 samples obtained from a control group composed of patients with febrile syndromes of other defined etiologies, asymptomatic subjects with past brucellosis or exposure to Brucella infection who had persistently high titers of anti-Brucella antibodies, and healthy subjects.

RESULTS

The sensitivities of LC-PCR with serum samples, PCR-ELISA with whole blood samples, and blood cultures were 93.3%, 90%, and 65%, respectively. Three control samples (8.1%) had a positive PCR-ELISA result, and 2 of these samples (5.4%) also had positive LC-PCR results. The specificity and positive likelihood ratios were 94.6% and 17.3, respectively, for LC-PCR and 91.9% and 11.1, respectively, for PCR-ELISA.

CONCLUSIONS

The diagnostic yield of LC-PCR with serum samples was higher than that of PCR-ELISA with whole blood samples. The speed and technical simplicity of LC-PCR in serum samples make it a useful alternative to blood cultures for patients with suspected brucellosis and negative or doubtful serological test results.