ABSTRACT In this study, B. cereus was detected in dialysis fluids within international parameters (ultrapure – maximum limit of 0.1 CFU/mL for heterotrophic bacteria count) by analyzing the pellet obtained through the centrifugation method. We also investigated the ability of the B. cereus isolate to form a biofilm at different temperatures, the production of virulence factors, and the susceptibility to commercial antimicrobial agents. This study demonstrated a high ability of B. cereus to persist in the hemodialysis system, which can be explained by its broad ability to produce a biofilm at 25 °C, its relevant production of virulence factors, such as β-hemolysin, lecithinase and cereulide, and its important resistance pattern to antimicrobial drugs. In conclusion, these new findings expand the understanding that this microorganism should not be neglected and new methods for tracking it should be considered.

Abstract In the current study, nanocapsules (NC) formulations containing a co-load of clotrimazole (C), a highly prescribed antifungal drug, and diphenyl diselenide [(PhSe)2], an organoselenium compound with a promising scope of pharmacological actions, were prepared. Formulations were characterized as well as the potential toxicity, antioxidant action, and antifungal effect were assessed using in vitro techniques. The NCs were prepared employing Eudragit® RS 100 as polymeric wall and medium chain triglycerides or virgin coconut oil (CO) as core. All NC suspensions had pH around acid range, compound content close to theoretical value (1 mg/mL/drug), average diameter in nanometric range, positive values of zeta potential as well as high encapsulation efficacy and mucoadhesive property. Physicochemical stability was performed over a 30-day period and showed no modification in the aforementioned parameters to all samples. Preliminary screening of toxicological potential performed by the hen’s egg test chorioallantoic membrane technique classified the formulations as non-irritant. The DPPH radical assay revealed that nanoencapsulated compounds had superior antioxidant action in comparison to their free forms (concentration range tested 1.0-25.0 µg/mL). Importantly, the formulation composed of CO and containing C and (PhSe)2 showed the highest antioxidant potential and was selected for further investigation regarding antifungal effect against some Candida spp strains. Results of in vitro antifungal assay demonstrated that the C and (PhSe)2 co-encapsulation had a minimum inhibitory concentration (MIC) values around 60. Thus, our study supplies additional data about advantages achieved by encapsulating active compounds.

Abstract Laboratory evidence has demonstrated the antimicrobial effect of Melaleuca alternifolia (MEL) against oral microorganisms. This randomized, double-blind, crossover clinical trial, compared the anti-biofilm and anti-inflammatory effects of MEL nanoparticles with 0.12% chlorhexidine gluconate (CHX) on biofilm-free (BF) and biofilm-covered (BC) surfaces. Before each experimental period, the participants refrained from all oral hygiene practices for 72 hours. The 60 participants were randomly assigned to professional prophylaxis in two quadrants (Q1–Q3 or Q2–Q4), and rinsed with MEL or CHX for four days. The Quigley & Hein plaque index (QHPI), gingival crevicular fluid (GCF) volume, and participants’ perceptions were assessed. CHX showed significantly lower mean QHPI on BF (2.65 ± 0.34 vs. 3.34 ± 0.33, p < 0.05) and BC surfaces (2.84 ± 0.37 vs. 3.37 ± 0.33, p < 0.05). Intragroup comparisons indicated reductions in GCF in all the groups, with significant differences only for CHX on BF surfaces (p < 0.05). Intergroup comparisons revealed no significant differences (p > 0.05). Based on individual perceptions, CHX had better taste and biofilm control, but resulted in a greater change in taste. Nevertheless, MEL demonstrated anti-inflammatory effects similar to those of CHX. Further clinical trials testing different protocols, concentrations and follow-up periods are required to establish its clinical application.

Resumo Objetivo Comparar a eficácia antimicrobiana de clorexidina 0,12% (CHX) e solução de chá verde (CV) (Camellia sinensis) em biofilmes formados em diferentes tensões de oxigênio em um modelo in situ. Método Vinte e cinco estudantes de odontologia foram elegíveis. Um dispositivo com espécimes de esmalte (EE) padronizados, voltado para o palato e para vestibular foram inseridos nos voluntários por 7 dias. Durante os primeiros quatro dias nenhum agente foi aplicado. A partir do quinto dia, ambos os agentes foram aplicados nos EEs no grupo teste e nenhum agente foi aplicado no grupo EE controle. Após 7 dias, os fragmentos EEs foram removidos dos dispositivos, sonicados, plaqueados em ágar, e incubado durante 24 h a 37 °C para determinar unidades formadoras de colonias (UFCs). Resultado CHX teve significativamente melhor eficácia em comparação com CV nos EEs para vestibular (1.330 vs. 2.170 UFC/mL) e EEs voltados para o palatal (2.250 vs. 2.520 UFC/mL). Comparações intragrupos mostraram maior eficácia em EEs vestibulares do que as EEs voltadas para o palato (1.330 vs. 2.250 UFC/mL para CHX e 2170 vs, 2520 UFC/mL para CV) em ambas as soluções. Análise dos controles, mostrou a formação de biofilme significativamente maior em comparação com EEs palatinas e bucais. Conclusão CHX tem uma eficácia maior do que o chá verde em biofilmes formados por 4 dias. A eficácia dos agentes foi reduzida para os biofilmes em ambiente com baixa tensão de oxigênio. A tensão de oxigênio parece influenciar na eficácia dos agentes testados.

Abstract Objective To compare the antimicrobial efficacy of a 0.12% chlorhexidine (CHX) and herbal green tea (Camellia sinensis) solution on established biofilms formed at different oxygen tensions in an in situ model. Method Twenty-five dental students were eligible for the study. In situ devices with standardized enamel specimens (ES) facing the palatal and buccal sides were inserted in the mouths of volunteers for a 7 day period. No agent was applied during the first four days. From the fifth day onward, both agents were applied to the test ES group and no agent was applied to the control ES group. After 7 days the ES fragments were removed from the devices, sonicated, plated on agar, and incubated for 24 h at 37 °C to determine and quantify the colony forming units (CFUs). Result CHX had significantly higher efficacy compared to green tea on the buccal (1330 vs. 2170 CFU/µL) and palatal (2250 vs. 2520 CFU/µL) ES. In addition, intragroup comparisons showed significantly higher efficacy in buccal ES over palatal ES (1330 vs. 2250 CFU/µL for CHX and 2170 vs, 2520 CFU/µL for CV) for both solutions. Analysis of the ES controls showed significantly higher biofilm formation in palatal ES compared to buccal ES. Conclusion CHX has higher efficacy than green tea on 4-day biofilms. The efficacy of both agents was reduced for biofilms grown in a low oxygen tension environment. Therefore, the oxygen tension environment seems to influence the efficacy of the tested agents.

Twenty-three isolates of Staphylococcus aureus resistant to methicillin have been analyzed, being found a clinical isolate of VISA through microdilution technique. The others techniques were unable to detect such isolates. This is the first study that shows the presence of VISA in clinical isolates in the city of Santa Maria-RS.

Aeromonas spp. were identified in five (2,7%) of 182 diarrheal stool cultures, A. caviae was predominant, resistant mainly to ampicillin and cephalotin. This is the first study showing the presence of Aeromonas spp. in diarrheal stools of outpatients in the central region of Rio Grande do Sul State, Brazil.

INTRODUÇÃO: A sepse é uma síndrome complexa causada pela resposta inflamatória sistêmica descontrolada. As citocinas inflamatórias representam papel central na patogênese do choque séptico. Têm sido testadas estratégias terapêuticas a fim de modular a geração ou a função excessiva de mediadores na sepse. OBJETIVO: O objetivo deste estudo foi investigar o efeito terapêutico da N-acetilcisteína (NAC) e sua associação com a frutose-1,6-bisfosfato (FBP) sobre a proliferação de linfócitos T e a geração de interleucina-1β (IL-1β) e proteína quimiotática de monócitos 1 (MCP-1) em cultura celular. MATERIAL E MÉTODOS: Foram isoladas células mononucleares de sangue periférico de indivíduos saudáveis. Os linfócitos T foram estimulados por 96 horas com fitohemaglutinina e submetidos a diferentes concentrações de NAC ou NAC associada à FBP (1,25 mM). RESULTADOS: O tratamento com NAC (10 e 15 mM) ou NAC (15 mM) associado à FBP reduziu a proliferação celular. Os níveis de IL-1β aumentaram com a presença de NAC (15 mM) e NAC + FBP. A concentração de MCP-1 mostrou-se reduzida apenas no grupo tratado com NAC associada à FBP. CONCLUSÃO: Os resultados sugerem que tanto a NAC quanto a NAC associada à FBP são capazes de inibir a proliferação celular, atuando como potentes agentes imunomoduladores, sugerindo seu uso em doenças inflamatórias.

INTRODUCTION: Sepsis is a complex syndrome caused by an uncontrolled systemic inflammatory response. Inflammatory cytokines play a pivotal role in septic shock pathogenesis. Therapeutic strategies have been tested in order to modulate the excessive generation or function of sepsis mediators. OBJECTIVE: The objective of the present study was to investigate the therapeutic effect of N-acetylcysteine (NAC) and its association with fructose-1,6-bisphosphate (FBP) on T-lymphocytes proliferation, interleukin-1β (IL-1β) and monocyte chemotactic protein-1 (MCP-1) levels. MATERIAL AND METHODS: Peripheral blood mononuclear cell samples were isolated from healthy individuals. T-lymphocytes were stimulated with phytohemagglutinin for 96 hours and submitted to different concentrations of NAC or NAC associated with FBP. RESULTS: NAC (10 and 15 mM) and NAC (15 mM) associated with FBP reduced T-lymphocytes proliferation. IL-1β levels rose in the presence of both NAC (15 mM) and NAC with FBP (1.25 mM). MCP-1 levels were reduced only by NAC (15 mM) associated with FBP (1.25 mM). CONCLUSION: The results suggest that both NAC itself and NAC associated with FBP inhibit cellular proliferation, acting as potent immunomodulatory agents, which corroborates its use in the treatment of inflammatory diseases.

INTRODUÇÃO: Os bacilos Gram-negativos não fermentadores (BGNNF) são frequentemente associados às infecções hospitalares. Além da alta incidência, esses microrganismos possuem resistência a diversos antimicrobianos. OBJETIVO: Analisar a prevalência e o perfil de resistência de BGNNF. MÉTODOS: Foram analisados 14.971 laudos de pacientes em um hospital privado de Porto Alegre-RS, no período de maio de 2006 a março de 2008, sem distinção de sexo e idade. RESULTADOS E CONCLUSÃO: Foram isoladas 326 amostras de BGNNF. As espécies mais prevalentes foram: Pseudomonas aeruginosa (65,03%), Acinetobacter baumannii (16,56%) e Stenotrophomonas maltophilia (9,5%). Outras espécies apresentaram índices inferiores a 5%. Os microrganismos foram isolados de diversos sítios infecciosos. Os materiais biológicos que apresentaram maior positividade para esses microrganismos foram o aspirado traqueal (38,34%), o escarro (18,71%) e a urina (15,95%). A resistência bacteriana mostrou-se mais expressiva a tetraciclinas (89,57%) e sulfametoxazol/trimetoprima (79,75%). Os antimicrobianos mais ativos foram polimixina B, com 100% de sensibilidade, e piperaciclina/tazobactam, com 75,2% de sensibilidade.

INTRODUCTION: The non-fermenting Gram-negative bacilli (NFGNB) have been widely associated with nosocomial infections. Not only are these microorganisms highly prevalent but they are also highly resistant to NFGNB. OBJECTIVE: To assess the prevalence and resistance profile of non-fermenting Gram-negative bacilli. METHODS: 14.971 patient reports from a private hospital in Porto Alegre, Rio Grande do Sul, from May/2006 to March/2008 were analyzed. RESULTS AND CONCLUSION: Three hundred twenty-six samples of non-fermenting Gram-negative bacilli were isolated. The most prevalent species were Pseudomonas aeruginosa (65.03%), Acinetobacter baumannii (16.56%), and Stenotrophomonas maltophilia (9.5%). Other species showed rates lower than 5%. The microorganisms were isolated from several infectious sites and the biological materials that showed higher positivity were the following: tracheal aspirate (38.34%), spittle (18.71%) and urine (15.95%). Bacterial resistance was higher with tetracyclines (89.57%) and sulfamethoxazole/trimethoprim (79.75%). The most active antimicrobials were polymyxin B and piperacillin/tazobactam with 100% and 75.2% sensibility, respectively.