No / Although Streptococcus agalactiae, the group B Streptococcus, is a leading cause of invasive neonatal disease worldwide the molecular basis of its virulence is still poorly understood. To investigate the role of lipoproteins in the physiology and interaction of this pathogen with host cells, we generated a mutant S. agalactiae strain (A909DeltaLgt) deficient in the Lgt enzyme and thus unable to lipidate lipoprotein precursors (pro-lipoproteins). The loss of pro-lipoprotein lipidation did not affect the viability of S. agalactiae or its growth in several different media, including cation-depleted media. The processing of two well-characterized lipoproteins, but not a non-lipoprotein, was clearly shown to be aberrant in A909DeltaLgt. The mutant strain was shown to be more sensitive to oxidative stress in vitro although the molecular basis of this increased sensitivity was not apparent. The inactivation of Lgt also resulted in changes to the bacterial cell envelope, as demonstrated by reduced retention of both the group B carbohydrate and the polysaccharide capsule and a statistically significant reduction (P=0.0079) in A909DeltaLgt adherence to human endothelial cells of fetal origin. These data confirm that failure to process lipoproteins correctly has pleiotropic effects that may be of significance to S. agalactiae colonization and pathogenesis.

La mastoïdite aiguë est l'une des complications les plus courantes de l'otite moyenne aiguë chez les enfants de moins de deux ans. Selon notre revue de la littérature, aucune directive nationale ou internationale ni étude prospective n’ont été émises concernant la sécurité des traitements de relai antibiotiques oraux ou intraveineux en période post-opératoire des mastoïdites aiguës sans complication intracrânienne. L’objectif de cette étude est de comparer les traitements antibiotiques post-opératoires oraux et intraveineux des mastoïdites aiguës sans complication intracrânienne chez l’enfant. Une étude de cohorte rétrospective par consultation de dossiers hospitaliers a été effectuée. Deux groupes d'enfants (n = 29) ayant subi une intervention chirurgicale appropriée, ont été comparés selon leurs données démographiques, selon le type d'antibiotiques utilisés en période postopératoire, selon la durée de leur hospitalisation ainsi que selon la prévalence des complications. Les deux groupes ont révélé des durées équivalentes d'hospitalisation et de traitement. Le groupe ayant reçu un traitement antibiotique intraveineux a présenté 14,3% de complications mineures (n = 2) et 7,1% de complications majeures (n = 1). Le groupe ayant reçu un traitement antibiotique oral a présenté 6,7% de complications mineures (n = 1) mais aucune complication majeure. Cette étude soutient l'idée que, dans la population pédiatrique, un drainage chirurgical adéquat des mastoïdites aiguës sans complication intracrânienne peut être suivi par un traitement antibiotique oral en toute sécurité avec des résultats similaires au traitement intraveineux post-opératoire. / Acute mastoiditis is one of the most common complication of acute otitis media in children under two years old. To our knowledge, neither guidelines have been published nor prospective study has compared the oral and intravenous post-operative antibiotic treatments of mastoïditis. Our objective was to compare the oral and intravenous post-operative treatments of pediatric acute mastoiditis without intracranial complication. A retrospective cohort study was done. Two groups of children (n = 29) diagnosed with acute mastoiditis without intracranial complication, who has been operated, were compared by the demographics, the type of antibiotics, the durations of hospitalization and postoperative treatment and the incidence of complications. Both groups had equivalent duration of hospitalization and postoperative treatment. The intravenous group had 14,3% of minor complications (n = 2) and 7,1% of major complications (n = 1). The oral group had 6,7% of minor complications (n = 1) without any major complication. This study supports the notion that, in the pediatric population, adequate surgical drainage of acute mastoiditis without intracranial complication can be followed by discharge with oral antibiotics to achieve the same satisfactory and safe outcomes of intravenous treatment.

Objectives This research project focused on the inhibitory effectiveness of a novel antimicrobial gel (AMG) towards a panel of common microbes involved in wound infections. Methods A novel antimicrobial topical gel consisting of vitamin E TPGS (tocopherol polyethylene glycol succinate), ascorbyl palmitate, zinc aspartate, lavender oil and deionized distilled water was developed in our laboratory. Various in vitro techniques were used to determine the effectiveness of AMG on prokaryotic and eukaryotic microbes. Results In vitro experiments show that while AMG had varying inhibitory effects on both prokaryotic and eukaryotic microbes, there was a predilection for AMG to inhibit planktonic growth and biofilm formation of Staphylococcus species, most notably Methicillin Resistant Staphylococcus aureus (MRSA). The inhibitory effect of the AMK on planktonic growth was immediate with a four-fold reduction in growth, compared to controls, within 4 to 6 hrs of induction. Within 24 hrs S. aureus growth was minimal and complete inhibition of growth was achieved within 48 hrs. In an in vitro biofilm model, the AMG inhibited Staphylococcus biofilm attachment by 67% (density), 82% (mass) and 95% (viability). On pre-formed established biofilms, the AMG was able to inhibit 47% (density), 47% (mass) and 44% (viability) Staphylococcus biofilms. Antibiotic comparison experiments demonstrated that the MIC (minimum inhibitory concentration) of Mupirocin was Conclusions AMG is nontoxic to humans and canines and demonstrates potential for use in wound infections as an alternative to commonly prescribed antibiotics without the unintended drug resistance seen with antibiotics. AMG is an effective treatment option, this far in vitro, for Staphylococcus infections that are particularly prone to biofilm growth.

No / Mono- and disaccharide-functionalised conjugates of the fluoroquinolone antibiotic ciprofloxacin have been synthesised and used as chemical probes of the bacterial uptake of glycosylated ciprofloxacin. Their antimicrobial activities against a panel of clinically relevant bacteria were determined: the ability of these conjugates to inhibit their target DNA gyrase and to be transported into the bacteria was assessed by using in vivo and in vitro assays. The data suggest a lack of active uptake through sugar transporters and that although the addition of monosaccharides is compatible with the inhibition of DNA gyrase, the addition of a disaccharide results in a significant decrease in antimicrobial activity.