Correlation between antibiotic susceptibilities and genotypes in Neisseria gonorrhoeae from different geographical origins: determinants monitoring by real- time PCR as a complementary tool for surveillance

ABSTRACT Objective To determine in Neisseria gonorrhoeae (NG) isolates from different geographical areas whether monitoring of major determinants involved in chromosomal antimicrobial resistance correlated with phenotypes and could constitute complementary tools for surveillance. Methods Real-time multiplex PCR assays targeting penA, mtrR, penB, ponA, gyrA and parC determinants were applied to 169 NG extracts. Minimum inhibitory concentrations for penicillin and ciprofloxacin were determined by E tests, and b-lactamase production was analysed using nitrocefin discs

Differential Cytokine Gene Expression According to Outcome in a Hamster Model of Leptospirosis

Leptospirosis is a widespread bacterial infection that is transmitted by soil or water contaminated by the urine of infected animals, or directly from these animals. It has highly diverse clinical presentations, making its differential diagnosis difficult. Though most cases are minor and self-resolving, there are also severe forms that include a sepsis pattern and multiple organ failure, and have possible fatal outcomes. Predictors of disease evolution and outcome are scarce, yet they would be very valuable to clinicians as well as to better decipher disease pathogenesis. In this study, we used a hamster model of leptospirosis to evaluate if immune genes were differentially expressed between individuals and if their expression levels could help forecast the outcome of the disease. We found that hamsters that later died from leptospirosis had significantly higher expression levels of both pro- and anti-inflammatory mediators compared to survivors. These results suggest that expression levels of these immune effectors might be helpful predictors of outcome in leptospirosis and that septic shock contributes to fatal leptospirosis

Protease of cryptococcus neoformans : role during infection and potential as prognostic evaluation biomarker

La cryptococcose est une infection opportuniste grave, associée à un taux de mortalité élevé en dépit d’un traitement antifongique adéquat. Dans un modèle murin de cryptococcose disséminée, les souris survivantes à l'inoculation d'une dose habituellement mortelle de Cryptococcus neoformans (Cn) ont majoritairement développé une réponse humorale contre une aspartyl protéase (PEP1). Nous avons évalué si une vaccination avec rPep1 et/ou une sérothérapie avec des anticorps anti-PEP1 pouvaient modifier le cours de l'infection.Par comparaison à une mortalité de 100 % chez les témoins, la vaccination de souris avec la protéine recombinante rPep1 avant l'inoculation des Cn permettait de prolonger leur survie et de diminuer leur charge fongique. Le vaccin thérapeutique basé sur une seule injection de rPep1 chez des souris préalablement infectées a prolongé leur survie, avec un contrôle partiel à total de leur infection dans les tissus. Le traitement de souris avec 1 injection d’anti-PEP1 7 jours après inoculation des Cn a permis de prolonger leur survie (effet dépendant de la souche de Cn, de l’Acm testé, du moment et de la dose administrée) par rapport aux souris traitées avec un Acm non pertinent. Les différents anti-PEP1 testés reconnaissaient plusieurs épitopes, n'ont pas démontré de capacité opsonisantes mais ont pu influencer la croissance de C. neoformans. L'expression in vivo du gène PEP1 était différente selon la souche inoculée, quel que soit le stade de la maladie et nous avons prouvé que PEP1 était sécrété dans le compartiment extracellulaire en association avec le développement de l'infection, suggérant pour PEP1, un rôle de possible biomarqueurCryptococcosis is a severe opportunistic infection associated with a 20 % mortality rate despite adequate antifungal therapy. In a relevant murine model of disseminated cryptococcosis, mice that survive the inoculation of a usually lethal challenge with Cryptococcus neoformans (Cn) were more likely to develop a delayed and monospecific antibody response against an aspartyl protease (PEP1). We assessed whether vaccination with rPep1 and/or serotheray with anti-PEP1 antibodies could alter the course of the infection. Compared to 100 % mortality rate in control mice, active immunization with recombinant protein rPep1 prior to Cn inoculation was associated with prolonged survival and decreased fungal burden. Therapeutic vaccine based on a single injection of rPep1 in mice previously infected provided prolonged survival with partial to total control of the infection of tissues. Passive serotherapy with 1 injection of anti-PEP1 Mabs 7 days after Cn inoculation led to a prolonged survival (dependent on the Cn strain, the Mab tested, the timing and the Mab dose) compared to mice treated with an irrelevant Mab. Anti-PEP1 Mabs have recognized different epitopes, have not demonstrated opsonisation capacity but were able to impact the growth of C. neoformans. The in vivo expression of the gene PEP1 was different depending on the inoculated strain, irrespective of the stage of the disease and we proved that Pep1 was secreted into the extracellular compartment in association with the development of infection, suggesting a possible role as biomarker for PEP1. These results suggest that immunomodulation with PEP1 or anti-PEP1 may be of benefit during disseminated cryptococcosi

Recent findings related to immune responses against leptospirosis and novel strategies to prevent infection

International audienceWhat are the new approaches and emerging ideas to prevent leptospirosis, a neglected bacterial re-emerging zoonotic disease? How do Leptospira interrogans escape the host defenses? We aim here to review and discuss the most recent literature that provides some answers to these questions, in particular data related to a better understanding of adaptive and innate immunity towards leptospires, and design of vaccines. This is an opinion paper, not a comprehensive review. We will try to highlight the new strategies and technologies boosting the search for drugs and vaccines. We will also address the bottlenecks and difficulties impairing the search for efficient vaccines and the many gaps in our knowledge of immunity against leptospirosis. Finally, we aim to delineate how Leptospira spp. escape the innate immune responses of Toll-Like receptors (TLR) and Nod-Like receptors (NLR). The rational use of TLR and NLR agonists as adjuvants could be key to design future vaccines against pathogenic leptospires

Relative normalized gene expression levels and <i>Leptospira</i> burdens of the hamsters at day 3 post-infections and p-values according to outcome in the LD50 experiments.

<p>Relative normalized gene expression levels and <i>Leptospira</i> burdens of the hamsters at day 3 post-infections and p-values according to outcome in the LD50 experiments.</p

IFNγ, TGFβ and IL-6 gene expression levels at day 3 post <i>Leptospira</i> infection (relative normalized expression, see text).

<p>Error bars indicate 95% confidence intervals. The insert shows the high variability observed in IL-6 gene expression levels.</p

Mean expression levels of differentially expressed genes (relative normalized expression, see text).

<p>Expression levels are shown at day 3 post-infection in the LD50 <i>Leptospira</i> infection (according to the outcome) and after the injection of a high dose of a virulent or the high-passage variant (A) and <i>Leptospira</i> burdens (B) in infected hamsters. Error bars indicate 95% confidence intervals.</p

Primers used in this study, amplicon size and elongation time.

<p>Primers used in this study, amplicon size and elongation time.</p