No / Propionibacterium acnes is the target of antimicrobial treatments for acne vulgaris. Acquired resistance to erythromycin, clindamycin and tetracyclines has been reported in strains from diverse geographical loci, but the molecular basis of resistance, via mutations in genes encoding 23S and 16S rRNA, respectively, has so far only been elucidated for isolates from the U.K. The study set out to determine whether similar or different resistance mechanisms occur in resistant P. acnes isolates from outside the U.K. The phenotypes and genotypes of 73 antibiotic-resistant strains of P. acnes obtained from the skin of acne patients in the U.K., U.S.A., France, Germany, Australia and Japan were compared. Antibiotic susceptibilities were determined by minimum inhibitory concentration (MIC) measurements, and polymerase chain reaction and DNA sequencing were used to identify mutations in genes encoding rRNA. Most erythromycin-resistant isolates (MIC90¿ 512 ¿g mL¿1) were cross-resistant to clindamycin but at a much lower level (MIC90¿ 64 ¿g mL¿1). As in the U.K., resistance to erythromycin was associated with point mutations in 23S rRNA in 49 of 58 strains. An A¿G transition at Escherichia coli equivalent base 2058 was present in 24 strains. This gave a unique cross-resistance phenotype against a panel of macrolide, lincosamide and type B streptogramin antibiotics. Two further point mutations (at E. coli equivalent bases 2057 and 2059) were identified (in three and 22 isolates, respectively) and these were also associated with specific cross-resistance patterns originally identified in isolates from the U.K. However, nine of 10 erythromycin resistant-strains from Germany did not exhibit any of the three base mutations identified and, in six cases, cross-resistance patterns were atypical. Consistent with previous U.K. data, 34 of 38 tetracycline-resistant strains carried a base mutation at E. coli 16S rRNA equivalent base 1058. Tetracycline-resistant isolates displayed varying degrees of cross-resistance to doxycycline and minocycline, but isolates from the U.S.A. had higher MICs for minocycline (4¿16 ¿g mL¿1) than isolates from other countries and, in particular, Australia. All the P. acnes isolates resistant to one or more of the commonly used antiacne antibiotics were sensitive to penicillin, fusidic acid, chloramphenicol and the fluoroquinolone, nadifloxacin. All but one isolate (from the U.K.) were sensitive to trimethoprim. This study shows that 23S and 16S mutations identified in the U.K. conferring antibiotic resistance in P. acnes are distributed widely. However, resistant strains were isolated in which mutations could not be identified, suggesting that as yet uncharacterized resistance mechanisms have evolved. This is the first report of high-level resistance to minocycline and is of concern as these strains are predicted to be clinically resistant and are unlikely to remain confined to the U.S.A. Epidemiological studies are urgently required to monitor how resistant strains are selected, how they spread and to ascertain whether the prevalence of resistance correlates with antibiotic usage patterns in the different countries.

Orientador: Ary Fernandes Junior / Resumo: Os óleos essenciais (OE) são produtos do metabolismo secundário da planta e são conhecidos pelas suas propriedades antimicrobianas. O principal componente do OE da palmarosa é o geraniol (70-80%). A incorporação de compostos da biodiversidade agrega valor as formulações dermocosméticas. OEs são uma boa opção devido à semelhança estrutural com o equilíbrio hidro-lipídico da pele. Assim, o objetivo do estudo foi avaliar a atividade antibacteriana desses compostos e o desenvolvimento de protótipos de dermocosméticos com nanopartículas para o tratamento da acne vulgar. Nanoemulsões com OE e geraniol foram preparadas de acordo com os valores do equilíbrio hidrofílico-lipofílico (EHL) e a caracterização das nanoemulsões seguiram os parâmetros da ANVISA (2004) para testes preliminares de estabilidade. Foram preparadas dez formulações. Nanoemulsões especiais contendo nanopartículas de prata (AgNP) foram preparadas e testadas contra C. acnes. Os ensaios de microtitulação com resazurina (REMA) foram realizados para determinar a Concentração Inibitória Mínima (CIM) e a Concentração Bactericida Mínima (CBM) para o OE de palmarosa e geraniol contra cepas American Type Culture Collection (ATCC) de Cutibacterium acnes 11827, 11828 e 6919. A curva de sobrevivência (CS) foi realizada para analisar o sinergismo entre os compostos e a clindamicina contra C. acnes, cepa 6919. As formulações foram estáveis ao pH, condutividade elétrica, densidade, centrifugação e análise de stress térmico. Anális... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Essential oils (EO) are secondary metabolism products of plant and they are known for antimicrobial properties.The major component of palmarosa EO is geraniol (70-80%). Incorporation of compounds of biodiversity guarantee value to dermocosmetic formulations. EOs are good option due to structural similarity with skin hydro-lipid balance. Thus, the desire was to evaluate the antibacterial activity to these compounds and the development of dermocosmetic prototypes with nanoparticles to treat acne vulgaris. Nanoemulsion with EO and geraniol were prepared according to values of lipophilic-hydrophilic balance (LHB) and nanoemulsions characterization followed the ANVISA (2004) parameters for preliminary stability tests. Ten formulations were prepared. Special nanoemulsion containing silver nanoparticles (AgNP) was prepared and tested against C. acnes. Resazurin Microtiter Assays (REMA) was performed to determine the Minimum inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) for palmarosa EO and geraniol against American Type Culture Collection (ATCC) strains of Cutibacterium acnes 11827, 11828 and 6919. The target of Time Kill Curve (TKC) test was determinate the synergism between compounds and clindamycin to C. acnes strain 6919. The formulations were stable to pH, electrical conductivity, density, centrifugation and thermal stress analysis. Analysis of size, zeta potential (ZP) and polydispersity index (PDI) were between 60 and 165 d.nm; -16.6 and -34.8 mv... (Complete abstract click electronic access below) / Mestre

The aim of this diploma thesis was to investigate the effect of surfactants and cosmetic polysaccharides on skin parameters and its microbiome. Three surfactants were tested to determine their effect: Sodium Dodecyl Sulfate (SDS), Cocamidopropyl Betaine (CAPB), Decylglucoside (DG). Distilled water was also used for comparison. For the next part of the experimental work were selected 6 polysaccharides: high molecular weight Hyaluronic Acid (HMW HA), very low molecular weight Hyaluronic Acid (VLMW HA), Sodium Caproyl Hyaluronate (CaproylHA), Sodium Carboxymethyl -Glucan (NaCMG), Schizophyllan and Glucomannan. For comparison, placebo and untreated control (only CAPB treatment) were also included in the tests. The first part of the work is a literature search on the assigned topic, which contains the following parts: skin anatomy and its biophysical properties, skin microbiome and its functions, description of used surfactants and polysaccharides. The experimental part is mainly focused on bioengineering methods for evaluation of skin parameters and qRT-PCR to determine the relative proportion of main bacterial species of skin microbiome. First, the effect on the CT gene of 16S rDNA was analysed, and Propionibacterium acnes and Staphylococcus epidermidis strains were selected for further analysis. In conclusion are presented an overview of all properties of selected substances and assessment of their application in cosmetics.

Les microbiotes humains sont considérés comme des organes supplémentaires impliqués dans des pathologies diverses, y compris infectieuses. Les déséquilibres des microbiotes, ou dysbioses, créent des niches écologiques pathologiques ou pathobiomes. Ce nouveau paradigme de l'infection s'applique tout particulièrement aux infections opportunistes. Dans ce travail, nous considérons des infections associées aux soins (IAS), les infections du site opératoire en chirurgie cardiaque, comme le résultat d'une pathologie de niche et nous étudions la dynamique des communautés et des populations microbiennes comme conditions d'émergence et de succès de l'agent infectieux. La diversité et la dynamique du microbiote chirurgical superficiel et profond de patients opérés pour pontage aorto-coronarien montrent un remplacement partiel du microbiote pré-opératoire par un microbiote spécifique avec une résilience partielle lors de la cicatrisation. Un lien significatif est observé entre la composition microbiotique et les marqueurs de risque infectieux. Le suivi de la structure de population d'un agent pathogène reconnu en chirurgie cardiaque, Propionibacterium acnes, montre des fréquences différentielles de phylotypes selon les phases opératoires. La spécificité du microbiote opératoire consiste en une forte diversité de bactéries à Gram négatif dont certaines ont été décrites dans le microbiote de la peau saine. Nous avons réalisé une identification au niveau de l'espèce de ces bactéries de la peau saine qui s'avèrent atypiques parmi les bactéries humaines connues car elles évoquent une origine environnementale. Le réservoir cutané et non environnemental d'un pathogène opportuniste, Roseomonas mucosa, est démontré et trois populations de pathogène opportuniste à réservoir environnemental et/ou humain (Pseudomonas aeruginosa, Ochrobactrum antropi, O. intermedium) sont étudiés en termes de structure de population pour préciser les conditions de leur transmission et leur succès infectieux dans le contexte général du pathobiome et des niches écologiques perturbées. Ce contexte général permet d'organiser les résultats obtenus à diverses échelles (communauté, populations, espèces, phylotypes) pour proposer une vision intégrée et originale de la microbiologie des IAS. / Human microbiota are now considered as supplementary organs involved in diseases such as infections. Microbiota disequilibrium named dysbiosis creates impaired ecological niches (pathobiomes). This new paradigm of infection is particularly relevant for opportunistic infections. In this study, we consider one major type of healthcare associated infection (HAI), the surgical site infections after cardiothoracic surgery as a pathology of niche. We study the dynamics of microbial communities and populations as conditions for emergence and success of infectious agents.The diversity and dynamics of superficial and deep surgical microbiota in patients undergoing coronary artery bypass grafting show a partial replacement of the pre-operative microbiota by a specific surgical microbiota with partial resilience during healing. Significant links are found between microbiota composition and scores for infectious risk. The population structure of Propionibacterium acnes, a pathogen complicating cardiac surgery, shows variable frequencies of phylotypes according to operative stages. Surgical microbiota appears specific with high diversity of Gram-negative bacteria, some of them being previously described in healthy skin microbiota. At the species-level, these bacteria appear atypical among known human bacteria because they are related to environmental bacteria. We demonstrate the cutaneous reservoir of the opportunistic pathogen Roseomonas mucosa deemed, until now, to be environmental. Three populations of opportunistic pathogens (Pseudomonas aeruginosa, Ochrobactrum anthropi, O. intermedium) are structured in order to precise their transmission and their infectivity in the general context of impaired ecological niche and pathobiome.The results obtained at various microbiological scale (community, population, species, phylotype) are organized in this general context in order to delineate an original integrative vision of HAI.