Diagnostic accuracy of a rapid E1-antigen test for chikungunya virus infection in a reference setting.

OBJECTIVES: Rapid diagnostic tests targeting virus-specific antigen could significantly enhance the diagnostic capacity for chikungunya virus infections. We evaluated the accuracy of an immunochromatographic antigen test for diagnosis of chikungunya in a reference laboratory for arboviruses. METHODS: An immunochromatographic rapid test that uses mouse monoclonal antibodies as a tracer against the E1-envelope protein of chikungunya (ARKRAY, Inc. Kyoto, Japan) was evaluated. Sensitivity was tested in sera from travellers with RT-PCR confirmed chikungunya virus infection (Eastern/Central/Southern African (ECSA) genotype) (n=9) and from patients diagnosed during the 2014-2015 chikungunya outbreak on Aruba (Asian genotype, n=30). Samples from patients with other febrile and non-febrile illnesses (n=26), sera spiked with Flavivirus and Alphavirus reference strains (n=13, including non-spiked serum), and samples containing other selected pathogens (n=20) were used to test specificity of the E1-antigen test. RESULTS: Sensitivity of the E1-antigen test was 8/9 (88.9%, 95% CI 56.5-98.0) for the ECSA genotype, but only 10/30 (33.3%, 95% CI 19.2-51.2) for the Asian genotype. Overall diagnostic specificity was 49/59 (83.1%, 95% CI 71.5-90.5). CONCLUSIONS: The E1-antigen test we evaluated had fair diagnostic sensitivity for ECSA genotype chikungunya, but low sensitivity for Asian genotype, and poor overall specificity. Antibodies that react across genotypes will be required for further development of a rapid test for chikungunya. Performance of new tests should be evaluated against different chikungunya genotypes.

Implementation of quality management for clinical bacteriology in low-resource settings.

BACKGROUND: The declining trend of malaria and the recent prioritization of containment of antimicrobial resistance have created a momentum to implement clinical bacteriology in low-resource settings. Successful implementation relies on guidance by a quality management system (QMS). Over the past decade international initiatives were launched towards implementation of QMS in HIV/AIDS, tuberculosis and malaria. AIMS: To describe the progress towards accreditation of medical laboratories and to identify the challenges and best practices for implementation of QMS in clinical bacteriology in low-resource settings. SOURCES: Published literature, online reports and websites related to the implementation of laboratory QMS, accreditation of medical laboratories and initiatives for containment of antimicrobial resistance. CONTENT: Apart from the limitations of infrastructure, equipment, consumables and staff, QMS are challenged with the complexity of clinical bacteriology and the healthcare context in low-resource settings (small-scale laboratories, attitudes and perception of staff, absence of laboratory information systems). Likewise, most international initiatives addressing laboratory health strengthening have focused on public health and outbreak management rather than on hospital based patient care. Best practices to implement quality-assured clinical bacteriology in low-resource settings include alignment with national regulations and public health reference laboratories, participating in external quality assurance programmes, support from the hospital's management, starting with attainable projects, conducting error review and daily bench-side supervision, looking for locally adapted solutions, stimulating ownership and extending existing training programmes to clinical bacteriology. IMPLICATIONS: The implementation of QMS in clinical bacteriology in hospital settings will ultimately boost a culture of quality to all sectors of healthcare in low-resource settings.

Fatal Chromobacterium violaceum bacteraemia in rural Bandundu, Democratic Republic of the Congo.

We describe the first case of bacteraemia caused by Chromobacterium violaceum in the Democratic Republic of the Congo. This diagnosis was made in an apparently healthy adult who was admitted to a rural hospital of the province of Bandundu with severe community-acquired sepsis. The patient developed multi-organ failure and died; to our knowledge, this is the first reported fatal case in an adult in Africa.

Percutaneous bunionette correction: results of a 49-case retrospective study at a mean 34 months' follow-up.

INTRODUCTION: Bunionette consists in a lateral prominence of the head of the fifth metatarsal (M5), inducing a callus. Toe malpositioning determines the varus, supraductus or infraductus form. HYPOTHESIS: A percutaneous method without osteosynthesis was assessed in 38 patients suffering from this pathology. PATIENTS AND METHODS: A continuous single-operator multicenter series operated on between May 2005 and January 2012 was analyzed with mean follow-up of 34 months. The inclusion criterion was bunionette with or without varus deviation. All patients were operated on percutaneously without tourniquet, on a day-care basis. All were clinically assessed, preoperatively and at latest FU, by visual analog pain scale (VAS), AOFAS and Coughlin scores, and callus status. Standard radiological assessment comprised monitoring of intermetatarsal (M4M5) and metatarsophalangeal (M5P1) angles. RESULTS: VAS decreased from 8 (range, 6-9) preoperatively to 0.3 (range, 0-1) out of 10 at follow-up. AOFAS score increased from 58 (range, 52-75) to 97 (range, 80-100) out of 100. According to the Coughlin score, 97.5% of patients were satisfied or very satisfied. Deformity correction was systematic, with disappearance of preoperative callus. M4M5 and M5P1 angles decreased respectively from 10° (range, 6-13°) and 16.2° (range, 8-24°) preoperatively to 5.5° (range, 4-8°) and 4.3° (range, 2-9°). There was 1 case of complex regional pain syndrome and 1 delayed consolidation. DISCUSSION: This procedure appeared reliable for correcting all types of bunionette deformity. Other minimally invasive methods with comparable results use pin fixation. The advantages over conventional techniques are the quality of results, low morbidity and absence of osteosynthesis material. The percutaneous technique should, we believe, be widely adopted in this indication. LEVEL OF EVIDENCE: IV.

Percutaneous internal fixation combined with kyphoplasty for neurologically intact thoracolumbar fractures: a prospective cohort study of 24 patients with one year of follow-up.

INTRODUCTION AND HYPOTHESIS: Neurologically intact lumbar and thoracolumbar fractures are frequent but their treatment is not codified. The purpose of this study was to evaluate the effectiveness of minimally invasive treatment of such fractures by percutaneous fixation associated with balloon kyphoplasty. PATIENTS AND METHODS: Between November 2008 and July 2010, 24 patients were treated. There were 12 men and 12 women, with a mean age of 53 years (range 20-88 years). Fractures were classified as one Magerl lesion type A1, one type A2, 19 A3 (five A31, 10 A32, four A33), and three type B2. The treatment was kyphoplasty of the fractured vertebra followed by percutaneous fixation of the vertebra above and below the fracture. Patient follow-up included an analysis of pain using the visual analogic score, the Oswestry score, and functional X-ray and CT analysis. RESULTS: Surgery lasted a mean 99 minutes. At the last follow-up, the mean pain was scored at 0.9 and the Oswestry score was 13.2. Reduction of vertebral kyphosis was 8.6° and reduction of the corrected regional angle was 7.1°. The gain in vertebral height was 17%. All pedicle screws were positioned correctly and no neurological, septic, or thromboembolic complications were observed. DISCUSSION AND CONCLUSION: Percutaneous osteosynthesis combined with balloon kyphoplasty is a valuable surgical technique in the treatment of thoracolumbar and lumbar fractures with no neurologic deficit. The clinical results are good and the technique allows the patient to return home earlier without having to wear a corset. The X-ray result scores are very encouraging, with corrections similar to conventional surgery in terms of vertebral height and kyphosis. This technique can be an alternative to conventional open surgery. LEVEL OF EVIDENCE: IV: Prospective observational study.

Fragile X syndrome. I. An overview on its genetic mechanism.

A large body of literature has accumulated within the last decade concerning the fragile X syndrome, the most common cause of X-linked mental retardation. The first article of this review summarizes the peculiar genetic mechanisms and molecular biology properties (eg, unstable DNA triplet repeats), which have been characterized since the detection of the FMR-1 gene in 1991. However, the most important question concerning the function of the FMR-1 gene is still an unresolved issue and is in need of future research. The second article of this review addresses the clinical picture, neuropsychological functioning and psychopathological characteristics of pre- and full mutation carriers.

New dual inhibitors of neutral endopeptidase and angiotensin-converting enzyme: rational design, bioavailability, and pharmacological responses in experimental hypertension.

In the treatment of cardiovascular diseases, it could be of therapeutic interest to associate the hypotensive effects resulting from the inhibition of angiotensin II formation, ensured by endothelial angiotensin-converting enzyme (ACE), with the diuretic and natriuretic responses due to the protection of the endogenous atrial natriuretic peptide (ANP) from inactivation by epithelial neutral endopeptidase (NEP). However, an investigation of this hypothesis requires an orally active compound able to jointly inhibit ACE and NEP. Dual inhibitors have therefore been designed by a rational approach, based on the characteristics of the active sites of both enzymes, which belong to the same family of zinc metallopeptidases, and on the structures of their most potent and selective inhibitors. As both NEP and ACE contain a large S'1-S'2 domain able to accommodate aromatic residues, the cyclic ACE inhibitor 3-(mercaptomethyl)-3,4,5,6-tetrahydro-2-oxo-1H-1-benzazocine-1-ace tic acid was selected as a template. Various aliphatic constraints were introduced on the benzyl moiety of the potent NEP inhibitor N-[2-(mercaptomethyl)-3-phenylpropanoyl]-L-tyrosine (IC50 NEP = 2 nM, IC50 ACE = 25 nM) to improve the fit between the computed most stable conformers of these molecules and the ACE template. New dual inhibitors, of general formula, N-[2(R,S)-(mercaptomethyl)-3(R,S)-phenylbutanoyl]-L-amino acid with IC50 values in the nanomolar range for both enzymes were generated by this approach. The separation of the four stereoisomers using chiral amines and the stereoselective synthesis of the 2-(mercaptomethyl)-3-phenylbutanoyl moiety showed that inhibitors with the 2S,3R configuration are the most potent on both NEP and ACE. The "in vivo" potency of various prodrugs of these inhibitors to inhibit ACE activity in lung and NEP activity in kidney was measured after oral administration in mice. From this pharmacokinetical study the most potent dual inhibitor RB 105 (N-[(2S,3R)-2-(mercaptomethyl)-3-phenylbutanoyl-L-alanine (compound 44c) (KI NEP 1.7 nM, KI ACE 4.5 nM) and its most efficient in vivo prodrug mixanpril, [N-[(2S,3R)-2-[(benzoylthio)methyl]-3-phenylbutanoyl]-L-alan ine (compound 18) (ED50 NEP approximately 1 mg/kg, ED50 ACE approximately 7 mg/kg) were selected. Competition experiments with a tritiated inhibitor of ACE or NEP bound to mouse lung and kidney membranes respectively showed that mixanpril has a long duration of action (> 8 h). As expected, after i.v. administration in the spontaneously hypertensive rat (SHR), RB 105 decreased blood pressure and increased diuresis and natriuresis.(ABSTRACT TRUNCATED AT 400 WORDS)

Charge polarity reversal inverses the specificity of neutral endopeptidase-24.11.

Attempts to change enzyme specificity by charge polarity reversal have so far met with little success, probably due to a destabilization of the resulting ion pair in an environment naturally optimized for the inverted pair. In the zinc metallopeptidase neutral endopeptidase-24.11 (EC 3.4.24.11), Arg102, involved in substrate binding, is probably located at the edge of the active site (Bateman, R.C., Jr., Kim, Y.-A., Slaughter, C., and Hersh, L.B. (1990) J. Biol. Chem. 265, 8365-8368; Beaumont, A., Le Moual, H., Boileau, G., Crine, P., and Roques, B.P. (1991) J. Biol. Chem. 266, 214-220). This environment may be favorable for polarity reversal, as in water the energies of reverse ion pairs would be identical. We show here that, while mutating Arg102 to Glu reduces the specificity of a C-terminally negatively charged substrate 16-fold, it increases that of a substrate with an optimally positioned positive charge 29-fold. The concept of charge polarity reversal can be extended to other zinc metallopeptidases, and the mutated enzyme could also have applications in the enantiomeric separation of unnatural amino acids.