Amphotericin-B and vancomycin-loaded chitosan nanofiber for antifungal and antibacterial application

In the present study, a mucoadhesive non-woven fiber mat (d= 116 nm) was fabricated by the electrospinning method using chitosan (80% Wt), polyethylene oxide (10% Wt), cysteine (4% Wt) and drugs (6% Wt), respectively. In addition, a comparative study was conducted to define effect of drugs and mucoadhesive agent on the nanofiber formation. FTIR, SEM, DSC and DMA were used to investigate the chemical and physical properties of the nanofibers. In vitro release of the drugs was assessed over a 48-hour period by the total immersion method. Release data were fitted to kinetic models, including the zero-order, first-order, Higuchi matrix, and Hixson-Crowell. Zone inhibition investigations were used to describe the inhibition content of vancomycin and amphotericin B loaded in the mats. The SEM images displayed a slight decrease in the fiber diameter with adding drugs and mucoadhesive agents. FTIR spectra confirmed that any undesirable reaction between VAN-AMB and CS-PEO was not observed. DSC test recognized the uniform distribution of drugs in the polymeric bead of the fiber without any crystal form. The elasticity modulus of the nanofiber was in an acceptable range for oral mucosa (approximately 5 Mpa). The results indicated that biodegradable mucoadhesive nanofibrous membranes released high concentrations of VAN in the first 24 hours, but the AMB release was affected in more controlled phenomena

Monitoramento plasmático e análise PK/PD dos antimicrobianos vancomicina e piperacilina no controle das infecções em pacientes queimados / Serum monitoring and PK/PD analysis of vancomycin and piperacillin for sepsis control in burn patients

Introdução: Reportam-se modificações metabólicas e hemodinâmicas em pacientes críticos em sepse e incluem-se neste grupo, os grandes queimados. Nesses pacientes ocorrem profundas alterações na farmacocinética de agentes antimicrobianos hidrofílicos prescritos no tratamento empírico das infecções bacterianas graves. Então, o alvo terapêutico não é alcançado em decorrência das concentrações plasmáticas desses antimicrobianos serem inferiores às requeridas para o controle das infecções. Na suspeita de sepse, a terapia antimicrobiana de primeira escolha prevê administração sistêmica dos antimicrobianos a vancomicina e a piperacilina, sendo esta última associada à tazobactana, um inibidor da beta-lactamase. Objetivo: Propôs-se nesse projeto a investigação da farmacocinética da vancomicina e da piperacilina através do monitoramento plasmático. Propôs-se ainda a avaliação da efetividade dos dois antimicrobianos na dose empírica recomendada com base na função renal aos pacientes críticos grandes queimados em sepse por patógeno hospitalar. Métodos: Investigaram-se 42 pacientes grandes queimados em terapia intensiva com lesões de 2° grau profundo e de 3° grau com suspeita de sepse por patógeno hospitalar. A prescrição constou de terapia combinada de vancomicina e piperacilina nas doses empíricas recomendadas com base na função renal de cada paciente. Seguem as características dos pacientes investigados: adultos de ambos os sexos (33M/9F), médias/ DP: 40,9±17,5 anos, 70,1±11,5 Kg, 33,6±20,7% de superfície corpórea total queimada (SCTQ), sendo 37/42 pacientes apresentaram função renal normal, e 5/42 pacientes com insuficiência renal, sem necessidade de prescrição de diálise pelo nefrologista. Registrou-se trauma térmico/ elétrico em 39/3; a lesão inalatória ocorreu em 25 pacientes. Efetuou-se coleta seriada de 2-3 amostras sanguíneas (Vacutainer/EDTA sódico); após separação do sangue por centrifugação a 2800g para obtenção do plasma, realizou-se o processamento laboratorial para os dois analitos pelo monitoramento plasmático da vancomicina e da piperacilina através da cromatografia líquida de alta eficiência. Realizou-se o estudo farmacocinético com base no modelo aberto monocompartimental. Através da análise PK/PD foi possível determinar os índices de efetividade para a vancomicina a partir da razão da área sob a curva no intervalo de 24 horas e a concentração inibitória mínima ASCss 0-24/CIM > 400, e para a piperacilina 70%fΔT>CIM; o significado desse último índice determinado para o derivado ß-lactâmico está relacionado a fração do intervalo de dose em que a concentração plasmática livre da piperacilina permanece acima da CIM. Resultados: Registrou-se alteração da farmacocinética da vancomicina e da piperacilina nos pacientes queimados com função renal normal pela comparação entre cada paciente e o valor de referência reportado para voluntários sadios. Nos pacientes com insuficiência renal registrou-se o prolongamento da meia vida biológica pela alteração na depuração e/ou no volume de distribuição. Registrou-se farmacocinética alterada em diferentes proporções tanto nos pacientes queimados com função renal preservada, como naqueles com disfunção renal. Após a análise PK/PD, a dose empírica de vancomicina administrada aos pacientes com função renal normal, registrou-se cobertura em 37/37 pacientes contra patógenos sensíveis (CIM 1mg/L), caindo para 18/37 (49%) pacientes para patógenos, CIM 2 mg/L. Não se registrou cobertura contra patógenos CIM>2 mg/L (CIM 4mg/L) independente da função renal dos pacientes. Após a dose empírica prescrita na função renal preservada, a cobertura da piperacilina ocorreu até CIM 4mg/L, para os patógenos sensíveis, caindo para 34/37 (92%) CIM 8 mg/L. Apenas 22/37 (60%) pacientes se encontraram protegidos contra patógenos sensíveis mais agressivos CIM 16 mg/L Pseudomonas aeruginosa e Enterococcus spp. Conclusão: O monitoramento plasmático da vancomicina e da piperacilina indica que a dose empírica recomendada para os dois agentes não alcança efetividade no controle das infecções causadas por patógenos hospitalares sensíveis à vancomicina (CIM>1mg/L) e à piperacilina (CIM >4 mg/L) em consequência de níveis plasmáticos inferiores aos requeridos no controle das infecções, devido a profundas alterações na farmacocinética desses antimicrobianos

Introduction: Metabolic and hemodynamic changes were reported in critically ill patients including burn patients in sepsis. Then, pharmacokinetics is altered in those patients mainly for hydrophilic antimicrobial agents prescribed for the control of severe bacterial infections; consequently, the therapeutic target wasn't reached based on drug plasma concentrations lower than expected. Antimicrobial therapy recommended in sepsis suspicious is based in a combination of two antimicrobials; vancomycin, a glycopeptides derivative and a beta-lactam agent piperacillin-tazobactam, a beta-lactamase inhibitor. Objective: It was proposed a pharmacokinetic investigation for vancomycin and piperacillin based on drug plasma monitoring followed by drug effectiveness measurements by PK/PD analysis after the empiric dose regimen recommended to normal renal function or renal failure burn patients in sepsis. Methods: 42 adult burn patients of both gender (33M/9F) with deep 2nd and 3rd injuries in septic shock by nosocomial pathogens under intensive care were investigated. A combined antimicrobial therapy at the recommended empirical dose regimen vancomycin-piperacillin was prescribed on the basis of renal function. Characteristics of population of patients investigated, means/SD were: 40.9±17.5 yrs, 70.1±11.5 kg, 33.6±20.7% total burn surface area (TBSA). Normal renal function was registered in 37/42 patients against 5/42 of them with renal failure. Thermal/electrical injuries occur in 39/3, and inhalation injury were in 25 of them. A serial of 2-3 blood samples were obtained from venous catheter into vacuum tubes (sodium EDTA); after centrifugation (2800g) plasma samples were obtained for drug plasma monitoring; both analytes, vancomycin and piperacillin were quantified by high performance liquid chromatography. Pharmacokinetics investigation based on one compartment open model was performed. PK/PD analysis was done to determine antimicrobial effectiveness against nosocomial pathogens isolated. Recommended drug effectiveness index was AUCss 0-24/MIC > 400 for vancomycin and 70%fΔT>MIC for piperacillin. Results: Pharmacokinetics for both antimicrobials investigated showed to be altered in a different extension for vancomycin and piperacillin in burn patients with normal renal function by comparison with reference data reported in healthy adult volunteers. PK/PD analysis indicated that after the initial dose regimen 2g daily for patients with normal renal function, the vancomycin effectiveness occurs only for susceptible pathogens MIC 1mg/L, once drug effectiveness falls to 49% (18/37) against pathogens (MIC 2mg/L). Similarly, piperacillin effectiveness occurs just for susceptible pathogens MIC ≤ 4 mg/L in patients with normal renal function, once only 22/37 (60%) of patients reached the target MIC 16mg/L for Pseudomonas aeruginosa and Enterococcus spp. Conclusion: Vancomycin and piperacillin plasma monitoring indicated that the therapeutic target wasn´t reached with the empiric dose regimen recommended against nosocomial pathogens vancomycin susceptible (MIC>1mg/L) and piperacillin susceptible (MIC >4 mg/L) due to plasma levels lower than expected as a consequence of kinetic disposition altered for both antimicrobials

Antimicrobial activity of essential oils against Vancomycin-Resistant enterococci (VRE) and Escherichia coli O157: H7 in feta soft cheese and minced beef meat

Eleven essential oils (EOs) were evaluated for their antibacterial properties, against Vancomycin-Resistant Enterococci (VRE) and E. coli O157:H7. EOs were introduced into Brain Heart Infusion agar (BHI) (15ml) at a concentration of 0.25 to 2 percent (vol/vol) to determine the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) for each pathogen evaluated. Results showed that the most active essential oils against bacteria tested were thyme oil, with MIC90 and MBC90 for the VRA strains of 0.25 percent and 0.5 percent, respectively. Eucalyptus, juniper and clove oils were the least potent agent, with MIC90 and MBC90 of 2 percent. Furthermore, the inhibitory effect of these EO were evaluated against VRE and E. coli O157:H7, experimentally inoculated (10³ cfu/g) in Feta soft cheese and minced beef meat, which was mixed with different concentrations (0.1 percent, 0.5 percent and 1 percent) of the EO and stored at 7 ºC for 14 days. Out of eucalyptus, juniper, mint, rosemary, sage, clove and thyme oils tested against target bacteria sage and thyme showed the best results. Clove and mint did not show any effect on VRE and E. coli O157:H7 in both kinds of studied foods. The addition of thyme oil at concentrations of 0.5 and 1 percent caused best significant reduction in the growth rate of VRE and E. coli O157:H7 in cheese and meat at 7 ºC. It is concluded that selected plant EOs can act as potent inhibitors of both microorganisms in a food product. The results revealed the potential of thyme oil as a natural preservative in feta soft cheese and minced beef meat against VRE and E. coli O157:H7 contamination.

Resumenes de articulos de la literatura pediatrica: vancomicina en combinación con otros antimicrobianos en el tratamiento de infecciones graves por staphylococcus aureus meticilino-resistente / Abstracts of articles in the pediatric literature: vancomycin in combination with other antimicrobials in the treatment of serious infections due to methicillin-resistant staphylococcus aureus

La vancomicina frecuentemente es combinada con otros antimicrobianos debido a su deficiencia en el tratamiento de infecciones graves por Staphylococus aureus meticilino resistente (MRSA).

Virulence factors in vancomycin-resistant and vancomycin - susceptible Enterococcus faecalis from Brazil / Fatores de virulência em Enterococcus faecalis resistentes e suscetível à vancomicina isolados no Brasil

Enterococci are members of commensal flora of animals and insects, but are also important opportunistic pathogens. Our objective was to observe if there was any difference of virulence in several groups of E. faecalis, mainly between vancomycin-resistant E. faecalis (VREFS) of colonization and infection. VREFS and vancomycin-sensitive E. faecalis from Brazil were screened for the presence of virulence factor genes. Phenotypic assays were used to assess in vitro expression, to understand the pathogenic potential of these isolates and to determine whether a correlation exists between virulence and antibiotic resistance. Different virulence profiles were found suggesting that the disseminating clone may have generated several variations. However, our study showed that one constellation of traits appeared most commonly: gelatinase, aggregation substance and esp (GEA). These factors are important because they have been implicated in cell aggregation and biofilm formation. Biofilm formation may promote the conjugation of plasmids harboring resistance and virulence genes, enhancing the probability of entry of new resistance genes into species. Curiously, the profile GEA was not exclusive to VREFS, it was the second most observed in VSEFS isolates from colonization and infection in hospitalized patients and also from rectal swabs of healthy volunteers. Such strains appear to represent the entry gateway to new resistance genes into E. faecalis and may contribute to the spreading of E. faecalis mainly in hospitals.

Enterococci são membros da microbiota comensal de animais e insetos, mas também são importantes patógenos oportunistas. Nosso objetivo foi observar se há qualquer diferença na virulência nos diversos grupos de Enterococcus faecalis, principalmente nos E. faecalis resistente à vancomicina (VREFS) isolados de colonização e infecção. VREFS e E. faecalis sensíveis à vancomicina (VSEFS) do Brasil foram pesquisadas quanto a presença de fatores de virulência. Ensaios fenotípicos foram usados para obter a expressão in vivo, entender o potencial patogênico destas amostras e determinar se existe correlação entre virulência e resistência a antibióticos. Diferentes perfis de virulência foram encontrados sugerindo que o clone que está se disseminado pode ter gerado diversas variações. No entanto, nosso estudo mostrou que um conjunto de fatores parece ser mais comum entre as amostras: gelatinase, substância de agregação e esp (GEA). Estes fatores tem sido correlacionados com a agregação de células e formação de biofilmes. A formação de biofilme pode promover a conjugação de plasmídeos contendo genes de resistência entre as espécies. Curiosamente, o perfil GAE não foi exclusivo para VREFS, foi o segundo mais observado em amostras VSEFS provenientes de colonização e infecção em pacientes hospitalizados e também de swabs retais de voluntários saudáveis. Tais linhagens pacerem representar a "porta de entrada" para novos genes de resistência em E. faecalis e podem contribuir para a disseminação de E. faecalis principalmente nos hospitais.

Estudo experimental de implantes bioabsorviveis de poli(L-acido latico) / poli(oxido de etileno) associados ao cloridrato de vancomicina no reparo osseo / An experimental study of the use of bioabsorbable polyl(L-lactic acid) / poly(ethylene oxide) microspheres containing vancomycin for bone repair

A necessidade da utilização de enxertos naturais e/ou materiais sintéticos para auxiliar no reparo ósseo é diretamente proporcional a perda tecidual nas lesões. A administração de substâncias antibióticas é necessária para prevenir, ou mesmo combater a ação de agentes bacterianos que possam vir a retardar o reparo tecidual. Este estudo teve como objetivo avaliar a aplicação de um polímero bioabsorvível associado à uma droga antobiótica na regenereção óssea. Foram realizados implantes ósseos de microesferas da blenda de poli(L-ácido lático)PLLA/poli(óxido de etileno)PEO na composição 80:20 associadas ao cloridrato de vancomicina e não associados ao cloridrato de vancomicina em ratos. Os implantes foram colocados em cavidades de 3 mm de diâmetro realizadas em tíbias de ratos da linhagem Wistar. Grupos com 5 animais cada. foram submetidos a períodos experimentais de 2 e 4 dias e 1, 2, 4, 8, 16 e 32 semanas. Os achados morfológicos foram semelhantes em ambos grupos. Houve primeiramente a formação de malha de fibrina e hemorragia ao redor das microesferas, as quais foram gradualmente sendo substituídas por tecido de granulação. A partir do quarto dia, houve a formação inicial de matriz óssea envolvendo as microesferas centripetamente, tornando-se mais evidente e madura da primeira até a trigésima segunda semana de implantação. A comparação entre os achados histomorfométricos...

The use of natural graft and synthetic materials to help bone regeneration is directly relative to cause of bone injury and bone requirement to compose a graft. The antibiotics drugs management is necessary to prevent and combat bacterial agents that could retard the tissue repair The aim of this study was to evaluate the bioabsorbable polymeric implants antibiotic associated behavior during the bone healing. Poly(L-lactic acid)PLLA/poly(ethylene oxide)PEO microspheres blends 80:20 vancomicyn associated bone implants, was compared with PLLA/PEO blend without vancomycin. The implants were inserted in a 3 mm proximal tibiae defect in adult Wistar rats. Periods from 2 and 4 days and 1. 2, 4, 8 16 and 32 weeks were evaluated in 5 animals per group. The histological findings were similar among groups. A fibrin net and hemorrhage were observed primarily around the microspheres and both were progressively replaced by granulation tissue. In four-day implant, the initial bone formation around microspheres was noted. The growth of bone tissue was initially characterized by wolven bone with progressive maturation to lamellar bone, centripetally to microspheres group. The quantity of new bone growth, measured by histomorphometric method and semi-quantitative analysis showed no differences between groups in each experimental interval. Therefore we conclude that mixing vancomycin chloridrate into PLLA/PEO microspheres did not affect...