ABSTRACT The treatment of infections caused by resistant microorganisms is limited, and vancomycin (VAN) treatment failures for methicillin-resistant Staphylococcus aureus (MRSA) bacteremia are not uncommon, even when MRSA clinical isolates are susceptible to VAN. Thus, this study proposed the association of VAN with usnic acid and β-lapachone encapsulated into liposomes as a novel therapeutic option for infections caused by MRSA. Liposomes containing β-lap (β-lap-lipo) or usnic acid (UA-lipo) were prepared by the thin lipid film hydration method followed by sonication. Antimicrobial activity against MRSA clinical isolates was investigated by the microdilution method according to the Clinical and Laboratory Standards Institute (CLSI). The interaction studies were carried out using the checkerboard method and epsilometer test (Etest). The interaction between VAN and β-lap or β-lap-lipo was synergistic (FICI = 0.453 and FICI = 0.358, respectively). An additive interaction between VAN and UA (FICI = 0.515) was found. UA-lipo resulted in synergism with VAN (FICI = 0.276). The Etest reproduced the results obtained by the checkerboard method for approximately 82% of the analysis. Thus, the present study demonstrated that VAN in combination with UA-lipo, β-lap or β-lap-lipo synergistically enhanced antibacterial activity against MRSA.

O objetivo deste estudo foi desenvolver e validar um método espectrofotométrico para determinação do LPSF/AC04 em complexo de inclusão e encapsulado em lipossomas. Os parâmetros de validação foram determinados de acordo com o International Conference on Harmonisation (ICH) e Agência Nacional de Vigilância Sanitária (ANVISA). OLPSF/AC04 foi determinado a 250 nm em metanol pelo método espectrofotométrico UV, que apresenta linearidade na faixa de 0,3 a 2 µg/mL (Absorbância = 0,18068 x [LPSF/AC04 µg/mL] + 0,00348), (r2 = 0,9995). Os limites de detecção e quantificação foi 0,047 µg/mL e 0,143 µg/mL, respectivamente. O método foi exato, preciso, reprodutível e robusto e todas as amostras analisadas apresentaram coeficiente de variação menor que 5% e não houve diferença estatisticamente significante entre a concentração teórica e a prática. Assim, um método espectrofotométrico rápido, simples, sensível e de baixo custo foi desenvolvido e validado para determinar o conteúdo do LPSF/AC04 em complexos de inclusão e encapsulados em lipossomas.

The aim of this study was to develop and validate a UV spectrophotometric method for determination of LPSF/AC04 from inclusion complex and encapsulated into liposomes. The validation parameters were determined according to the International Conference on Harmonisation (ICH) and National Health Surveillance Agency (ANVISA) guidelines. LPSF/AC04 was determined at 250 nm in methanol by a UV spectrophotometric method, exhibiting linearity in the range from 0.3 to 2 µg.mL−1 (Absorbance=0.18068 x [LPSF/AC04 µg.mL-1] + 0.00348), (r2=0.9995). The limits of detection and quantification were 0.047µg.mL−1 and 0.143µg.mL−1, respectively. The method was accurate, precise, reproducible and robust since all the samples analyzed had coefficient of variation of less than 5% and no statistically significant difference between theoretical and practical concentrations was detected. Thus, a rapid, simple, low cost and sensitive spectrophotometric method was developed and validated for determining the content of inclusion complex and liposomes containing LPSF/AC04.

O objetivo do presente estudo foi analisar a freqüência de oocistos de Cryptosporidium spp em amostras fecais de crianças, de 1 a 14 anos, de uma creche pública localizada em uma comunidade carente da cidade do Recife, Pernambuco. A pesquisa foi realizada no período de 28 de junho de 2006 a 3 de abril de 2007, e envolveu 182 crianças. Das amostras analisadas 59 (32,4%) foram positivas quanto à presença de oocistos de Cryptosporidium spp, e a faixa etária mais acometida foi a de 3 a 5 anos de idade (54,2%). A alta freqüência de amostras positivas para Cryptosporidium spp obtidas neste estudo comprovam que creches são ambientes propícios a essa ocorrência devido ao contato direto entre criança-criança, crianças e funcionários. A maior via de infecção por Cryptosporidium spp é a transmissão interpessoal, que é bem ilustrada em creches. A imaturidade, deficiências do sistema imune e hábitos higiênicos inadequados são fatores que também contribuem para esse tipo de infecção.

The objective of the present study was to analyze the frequency of oocysts of Cryptosporidium spp in fecal samples from children aged one to fourteen years at a public daycare center located in a needy community in the city of Recife, Pernambuco. The investigation was carried out between June 28, 2006, and April 3, 2007, and involved 182 children. Among the samples analyzed, 59 (32.4%) were positive regarding the presence of oocysts of Cryptosporidium spp, and the age group most affected was between three and five years (54.2%). The high frequency of samples positive for Cryptosporidium spp obtained in this study confirms that daycare centers are an environment that favors such occurrences, because of the direct contact between children or between children and staff. The most important infection route for Cryptosporidium spp is person-to-person transmission, which is well illustrated in daycare centers. Immaturity, deficiencies of the immune system and inadequate hygiene habits are factors that also contribute towards this type of infection.