Recent Advances in Surface Nanoengineering for Biofilm Prevention and Control. Part I: Molecular Basis of Biofilm Recalcitrance. Passive Anti-Biofouling Nanocoatings.

Medical device-associated infections are becoming a leading cause of morbidity and mortality worldwide, prompting researchers to find new, more effective ways to control the bacterial colonisation of surfaces and biofilm development. Bacteria in biofilms exhibit a set of "emergent properties", meaning those properties that are not predictable from the study of free-living bacterial cells. The social coordinated behaviour in the biofilm lifestyle involves intricate signaling pathways and molecular mechanisms underlying the gain in resistance and tolerance (recalcitrance) towards antimicrobial agents as compared to free-floating bacteria. Nanotechnology provides powerful tools to disrupt the processes responsible for recalcitrance development in all stages of the biofilm life cycle. The present paper is a state-of-the-art review of the surface nanoengineering strategies currently used to design antibiofilm coatings. The review is structurally organised in two parts according to the targeted biofilm life cycle stages and molecular mechanisms intervening in recalcitrance development. Therefore, in the present first part, we begin with a presentation of the current knowledge of the molecular mechanisms responsible for increased recalcitrance that have to be disrupted. Further, we deal with passive surface nanoengineering strategies that aim to prevent bacterial cells from settling onto a biotic or abiotic surface. Both "fouling-resistant" and "fouling release" strategies are addressed as well as their synergic combination in a single unique nanoplatform.

Resistência antimicrobiana associada em isolados clínicos de Enterococcus spp / Associated antimicrobial resistance in Enterococcus spp. clinical isolates

INTRODUÇÃO: O aumento da prevalência de isolados de enterococos em hospitais, particularmente Enterococcus resistente à vancomicina (VRE), é importante por causa da limitada terapia antimicrobiana efetiva para o tratamento de infecções enterocócicas. MÉTODOS: O presente trabalho apresentou uma investigação retrospectiva de dados de suscetibilidade in vitro quantitativa para uma variedade de antimicrobianos frente aos isolados de Enterococcus spp. e avaliação da associação de resistência entre os agentes antimicrobianos apontados como escolha para o tratamento de infecções causadas por VRE, através do cálculo do risco relativo. RESULTADOS: Dos 156 isolados de enterococos, 40 (25,6 por cento) foram resistentes a três ou mais antimicrobianos, incluindo 7,7 por cento (n = 12/156) resistentes à vancomicina. A associação de resistência elevada foi mais pronunciada entre os isolados de VREs com antimicrobianos alternativos e primários para o tratamento de infecções causadas por estes patógenos, incluindo ampicilina (100 por cento, RR = 7,2), estreptomicina (90,9 por cento, RR = 4,9), rifampicina (91,7 por cento, RR = 3,1) e linezolida (50 por cento, RR = 11,5), apesar da alta taxa de suscetibilidade a esta droga (94,9 por cento). CONCLUSÕES: A resistência associada significativa aos antimicrobianos de primeira escolha e alternativos, usados no tratamento de infecções graves por cepas com o fenótipo VRE e que requerem um regime terapêutico combinado, evidencia alternativas terapêuticas ainda mais limitadas na instituição analisada.

INTRODUCTION: The increasing prevalence of enterococci strains in hospitals, particularly among isolates of vancomycin-resistant enterococci (VRE), poses important problems because of the limited effect of antimicrobial therapy for enterococcal infections. METHODS: This work presents a retrospective investigation of quantitative in vitro susceptibility data for the range of antimicrobials against Enterococcus spp. isolates and evaluation of the association of resistance between antimicrobial agents recommended as the treatment of choice for infections caused by VRE through calculation of the relative risk. RESULTS: Of the 156 enterococci isolates, 40 (25.6 percent) were resistant to 3 or more antimicrobials, including 7.7 percent (n = 12/156) vancomycin resistant. The association of elevated resistance was more pronounced among VRE isolates against alternative and primary antimicrobials for the treatment of infections caused by these pathogens, including ampicillin (100 percent, RR = 7.2), streptomycin (90.9 percent, RR = 4.9), rifampin (91.7 percent, RR = 3.1) and linezolid (50 percent, RR = 11.5), despite high susceptibility to this drug (94.9 percent). CONCLUSIONS: The significant associated resistance to alternative and first choice antimicrobials used in the treatment of serious infections of strains with the VRE phenotype and that require a combined therapeutic regime, revealed even more limited therapeutic alternatives in the institution analyzed.

Determinação da resistência antimicrobiana associada em isolados clínicos de Staphylococcus aureus e Pseudomonas aeruginosa em um hospital público de Goiânia, Estado de Goiás / Determination of associated antimicrobial resistance in clinical isolates of Staphylococcus aureus and Pseudomonas aeruginosa in a public hospital in Goiânia, State of Goiás

Este estudo avaliou a resistência antimicrobiana associada de Pseudomonas aeruginosa e Staphylococcus aureus a um agente antimicrobiano com outras drogas. A resistência antimicrobiana associada foi calculada através do risco relativo. Houve uma relação óbvia entre resistência à oxacilina e a outros agentes antimicrobianos entre os isolados de Staphylococcus aureus resistentes à oxacilina (68,5 por cento) superior a 32 por cento, com exceção da linezolida (6,7 por cento). Resistência associada pronunciada entre drogas foi observada para isolados de Pseudomonas aeruginosa, particularmente entre ciprofloxacina e os carbapenens (59,6 por cento a 60,7 por cento), entre aminoglicosídeos e carbapenens (66,3 por cento a 67,7 por cento) e os demais β-lactâmicos (52,3 por cento a 85,8 por cento). O presente trabalho enfatiza a importância da cultura diagnóstica e do teste de suscetibilidade na seleção de um correto agente antimicrobiano com relação ao impacto clínico no aumento da multirresistência e na seleção de resistência antimicrobiana associada.

This study evaluated the associated antimicrobial resistance of Pseudomonas aeruginosa and Staphylococcus aureus in relation to an antimicrobial agent with other drugs. The associated antimicrobial resistance was calculated by means of the relative risk. There was an obvious relationship between oxacillin resistance and resistance to other antimicrobial agents among isolates of oxacillin-resistant Staphylococcus aureus (68.5 percent), greater than 32 percent, except for linezolid (6.7 percent). Pronounced associated resistance among drugs was observed for Pseudomonas aeruginosa isolates, particularly for ciprofloxacin and carbapenems (59.6 percent to 60.7 percent) and for aminoglycosides and carbapenems (66.3 percent to 67.7 percent) and other β-lactam antibiotics (52.3 percent to 85.8 percent). The present study emphasizes the importance of diagnostic cultures and susceptibility testing for selecting the correct antimicrobial agent, with regard to the clinical impact of increased multiresistance and selection of associated antimicrobial resistance.