Lyme Borreliosis: human impact on the peristance and circulation of Borrelia Burgdorferi sensu lato in the environment

Lyme disease is a bacterial infection transmitted by hard ticks of the genus Ixodes. It is primarily a zoonosis which circulates in a wide range of vertebrate hosts, wild animals (lizards, birds, rodents, deer…) and domestic animals: humans are accidental hosts. In recent years, the notion of emergence has been raised, especially because of climate changes. The reasons are more complex. The disease is better known medically: it is better diagnosed and the epidemiology is more and more understood. In addition, analysis of various biotic and abiotic factors suggests that Humans impact directly the environments where ticks evolve. Indeed, for socio-economic reasons they have modified forest ecosystems and wildlife that favor the development of tick populations and consequently tick borne diseases.La borréliose de Lyme est une infection bactérienne transmise par les tiques dures du genre Ixodes. C’est avant tout une zoonose qui circule dans un large panel d’hôtes vertébrés sauvages (lézards, oiseaux, rongeurs, cervidés…) et domestiques ; l’homme est un hôte accidentel. Ces dernières années, la notion d’émergence a été évoquée pour cette pathologie, notamment à cause des modifications climatiques. Les raisons sont plus complexes. La pathologie est mieux connue sur un plan médical grâce aux progrès diagnostiques, cliniques et épidémiologiques. De plus, l’analyse des différents facteurs biotiques et abiotiques laissent penser que l’anthropisation des environnements où évoluent les tiques, est responsable de l’émergence des maladies transmises par les tiques dont la borréliose de Lyme. En effet, l’homme modifie pour des raisons socio-économiques surtout, les écosystèmes forestiers et la faune sauvage qui favorisent le développement des populations de tique et donc des maladies qu’elles transmettent

Borrelia burgdorferi Infection and Cutaneous Lyme Disease, Mexico

Four patients who had received tick bites while visiting forests in Mexico had skin lesions that met the case definition of erythema migrans, or borrelial lymphocytoma. Clinical diagnosis was supported with histologic, serologic, and molecular tests. This study suggests the Borrelia burgdorferi infection is in Mexico

Immunoglobulin deficiency in patients with Streptococcus pneumoniae or Haemophilus influenzae invasive infections

SummaryObjectivesImmunoglobulin (Ig) deficiency is a well-known risk factor for Streptococcus pneumoniae or Haemophilus influenzae infections and noteworthy invasive diseases. However, the proportion of these deficiencies in cases of invasive disease is unknown. The objective of this study was to evaluate the rate of Ig deficiency in cases of invasive disease.MethodsA prospective study was conducted from January 2008 to October 2010 in two French hospitals. Measurement of Ig levels was carried out in patients hospitalized for invasive diseases.ResultsA total of 119 patients were enrolled in the study, with nine cases of H. influenzae and 110 cases of S. pneumoniae invasive disease. There were 18 cases of meningitis, 79 of invasive pneumonia, and 22 other invasive diseases. Forty-five patients (37.8%) had an Ig abnormality, 37 of whom had an Ig deficiency (20 IgG <6g/l, four isolated IgA <0.7g/l, and 13 isolated IgM <0.5g/l), while eight had an elevated monoclonal paraprotein. Nineteen of these 45 patients had a clearly defined Ig abnormality, with five primary deficiencies (three common variable immunodeficiencies and two complete IgA deficiencies) and 14 secondary deficiencies, mainly lymphoproliferative disorders. All these deficiencies were either not known or not substituted.ConclusionsHumoral deficiency is frequent in patients with S. pneumoniae or H. influenzae invasive disease and Ig dosage should be proposed systematically after such infections

In vitro activity of daptomycin against Enterococcus faecalis under various conditions of growth-phases, inoculum and pH

Enterococcus faecalis (E. faecalis) has become a major leading cause of nosocomial endocarditis. Treatment of such infections remains problematic and new therapeutic options are needed. Nine E. faecalis strains were tested: six obtained from patients presenting endocarditis, one with isolated bacteremia, and two reference strains. Antibiotics included daptomycin, alone or in combination, linezolid, tigecycline, rifampicin, gentamicin, teicoplanin, ceftriaxone and amoxicillin. Time-kill studies included colony counts at 1, 4 and 24 h of incubation. Significant bactericidal activity was defined as a decrease of ≥3log10CFU/ml after 24 h of incubation. Antibiotics were tested at a low (10(6) CFU/ml) and high (10(9) CFU/ml) inoculum, against exponential- and stationary-phase bacteria. We also performed time kill studies of chemically growth arrested E. faecalis. Various pH conditions were used during the tests. In exponential growth phase and with a low inoculum, daptomycin alone at 60 µg/ml and the combination amoxicillin-gentamicin both achieved a 4-log10 reduction in one hour on all strains. In exponential growth phase with a high inoculum, daptomycin alone was bactericidal at a concentration of 120 µg/ml. All the combinations tested with this drug were indifferent. In stationary phase with a high inoculum daptomycin remained bactericidal but exhibited a pH dependent activity and slower kill rates. All combinations that did not include daptomycin were not bactericidal in conditions of high inoculum, whatever the growth phase. The results indicate that daptomycin is the only antibiotic that may be able of overcoming the effects of growth phase and high inoculum

PLoS ONE

Lyme disease is a multisystemic disorder caused by B. burgdorferi sl. The molecular basis for specific organ involvement is poorly understood. The skin plays a central role in the development of Lyme disease as the entry site of B. burgdorferi in which specific clones are selected before dissemination. We compared the skin inflammatory response (antimicrobial peptides, cytokines and chemokines) elicited by spirochete populations recovered from patients presenting different clinical manifestations. Remarkably, these spirochete populations induced different inflammatory profiles in the skin of C3H/HeN mice. As spirochete population transmitted into the host skin is heterogeneous, we isolated one bacterial clone from a population recovered from a patient with neuroborreliosis and compared its virulence to the parental population. This clone elicited a strong cutaneous inflammatory response characterized by MCP-1, IL-6 and antimicrobial peptides induction. Mass spectrometry of this clone revealed 110 overexpressed proteins when compared with the parental population. We further focused on the expression of nine bacterial surface proteins. bb0347 coding for a protein that interacts with host fibronectin, allowing bacterial adhesion to vascular endothelium and extracellular matrix, was found to be induced in host skin with another gene bb0213 coding for a hypothetical protein. These findings demonstrate the heterogeneity of the B. burgdorferi ss population and the complexity of the interaction involved early in the skin