Lyme borreliosis, caused by spirochaetes of the Borrelia burgdorferi genospecies complex, is the most commonly reported tick-borne infection in Europe and North America. The non-specific nature of many of its clinical manifestations presents a diagnostic challenge and concise case definitions are essential for its satisfactory management. Lyme borreliosis is very similar in Europe and North America but the greater variety of genospecies in Europe leads to some important differences in clinical presentation. These new case definitions for European Lyme borreliosis emphasise recognition of clinical manifestations supported by relevant laboratory criteria and may be used in a clinical setting and also for epidemiological investigations.

BackgroundInterpretation of serological assays in Lyme borreliosis requires an understanding of the clinical indications and the limitations of the currently available tests. We therefore systematically reviewed the accuracy of serological tests for the diagnosis of Lyme borreliosis in Europe.MethodsWe searched EMBASE en MEDLINE and contacted experts. Studies evaluating the diagnostic accuracy of serological assays for Lyme borreliosis in Europe were eligible. Study selection and data-extraction were done by two authors independently. We assessed study quality using the QUADAS-2 checklist. We used a hierarchical summary ROC meta-regression method for the meta-analyses. Potential sources of heterogeneity were test-type, commercial or in-house, Ig-type, antigen type and study quality. These were added as covariates to the model, to assess their effect on test accuracy.ResultsSeventy-eight studies evaluating an Enzyme-Linked ImmunoSorbent assay (ELISA) or an immunoblot assay against a reference standard of clinical criteria were included. None of the studies had low risk of bias for all QUADAS-2 domains. Sensitivity was highly heterogeneous, with summary estimates: erythema migrans 50 % (95 % CI 40 % to 61 %); neuroborreliosis 77 % (95 % CI 67 % to 85 %); acrodermatitis chronica atrophicans 97 % (95 % CI 94 % to 99 %); unspecified Lyme borreliosis 73 % (95 % CI 53 % to 87 %). Specificity was around 95 % in studies with healthy controls, but around 80 % in cross-sectional studies. Two-tiered algorithms or antibody indices did not outperform single test approaches.ConclusionsThe observed heterogeneity and risk of bias complicate the extrapolation of our results to clinical practice. The usefulness of the serological tests for Lyme disease depends on the pre-test probability and subsequent predictive values in the setting where the tests are being used. Future diagnostic accuracy studies should be prospectively planned cross-sectional studies, done in settings where the test will be used in practice.

Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) is now widely used for marker/multi-biomarker detection in medical diagnosis. We tested a new protocol for bacterial identification from blood culture broths in hospital routine by using collection tubes with separator gels on 503 included samples examined over 3 months, where 1.5 mL was injected by a syringe into BD Vacutainer tubes from BACTEC-positive bottles, before processing for bacterial protein extraction. Samples were loaded in duplicate onto the MALDI MS target, allowing a series of 12 samples to be processed in duplicate within 80 min by using Biflex III and BioTyper 2.0 software (Bruker). Including polymicrobial samples, 193 of 213 of Gram-negative bacteria (91.08%) and 284 of 319 of Gram-positive bacteria (89.02%) were correctly identified at the species level. Enterobacteriaceae constituted 35.15% of all species found, Staphylococaceae 37.96%, Streptococaceae and Enterococaceae 20.85%, Pseudomonadaceae 1.69%, and anaerobes 2.44%. In most of the polymicrobial samples, one of the species present was identified (80.9%). Seven isolates remained misidentified as Streptococcus pneumoniae, all belonging to Streptococcus mitis. Staphylococcus aureus was identified better when grown on anaero-aerobic medium, and MALDI BioTyper identification scores as low as 1.4 were pertinent, provided that four successive proposals of the same species were given. This new protocol correlates with conventional microbiology procedures by up to 90%, and by >95% for only monomicrobial samples, and provides a decreased turn-around time for identification of bacteria isolated from blood cultures, making this technology suitable also for blood cultures, with less delay and cost decreases in bacterial diagnostics, and favouring better care of patients.

Pulsed-field gel electrophoresis (PFGE) after SmaI restriction of DNA from 239 methicillin-resistant Staphylococcus aureus isolates (from 142 patients) produced 26 different fingerprints. The deduced chromosome sizes ranged from 2,200 to 3,100 kb (+100 kb). A total of 81 isolates taken from 65 patients were then typed by PFGE and ribotyping with ClaI, EcoRI, and HindIII. Ribotypes were less discriminating than PFGE. Ribotyping did not discriminate isolates from a given PFGE fingerprint into different subsets. PFGE may be a more effective epidemiological tool than ribotyping for the typing of methicillin-resistant S. aureus strains.

The main recommendations according to current European case definitions for LB are as follows. Typical erythema migrans should be diagnosed clinically and does not require laboratory testing. The diagnosis of Lyme neuroborreliosis requires laboratory investigation of the spinal fluid including intrathecal antibody production, and the remaining disease manifestations require testing for serum antibodies to B. burgdorferi. Testing individuals with non-specific subjective symptoms is not recommended, because of a low positive predictive value.

Borréliose de Lyme et autres maladies vectorielles à tiques. Recommandations des sociétés savantes françaises. Argumentaire 2 : diagnostic biologique, traitement, symptômes persistants au décours d'une borréliose de Lyme documentée ou suspectée. Lyme borreliosis and other tick-borne diseases. Guidelines from the French scientific societies (II). Biological diagnosis, treatment, persistent symptoms after documented or suspected Lyme borreliosis.

The antibody index has a very good specificity but only moderate sensitivity. Given the lack of consensual criteria for neuroborreliosis and the absence of a "gold standard" diagnostic test, we propose pragmatic diagnostic criteria for neuroborreliosis, namely the presence of four of the following five items: no past history of neuroborreliosis, positive CSF ELISA serology, positive anti-Borrelia antibody index, favorable outcome after specific antibiotic treatment, and no differential diagnosis. These new criteria will need to be tested in a larger, prospective cohort.

Cat scratch disease (CSD) is mostly due to Bartonella henselae after inoculation of the organism through a skin injury. Since the causative bacteria cannot be easily cultured from human lymph node samples, the diagnosis usually relies on epidemiological, clinical, histological, and serological criteria (classical criteria). A study was performed to determine the diagnostic value of PCR analysis for the detection of B. henselae for the diagnosis of CSD and its place in the diagnostic strategy alongside the classical criteria. Over a 7-year period, lymph node biopsy specimens or cytopunctures from 70 patients were systematically tested by PCR for the presence of B. henselae DNA (htrA gene) in the Bacteriology Laboratory of the Hôpitaux Universitaires de Strasbourg. Serological testing by an immunofluorescence assay for B. henselae antibodies was also performed for each patient, and clinical, epidemiological, and histological data were collected. The patients were then divided into two groups according to the number of positive diagnostic criteria for CSD: 29 patients with definite CSD (two or more classical criteria) and 15 patients with possible CSD (less than two classical criteria). The remaining 26 patients for whom another diagnosis was retained were used as a control group. Among all criteria, PCR analysis had the best specificity (100%). The PCR assay for B. henselae was positive for 22 (76%; 95% confidence interval [CI 95 ], 56.5 to 89.7%) of the 29 definite CSD patients and 3 (20%; CI 95 , 4.3 to 48.1%) of the 15 possible CSD patients. We then studied combinations of diagnostic criteria, including B. henselae PCR analysis. The best diagnostic performance was observed if at least two criteria were present among serologic, epidemiologic, histological, and molecular criteria.