Polymyxins are a group of antibacterial substances and have remained the drugs of choice for treatment of resistant Gram-negative bacilli. Polymyxin B is administered by intravenous infusion and requires the reconstitution of lyophilized powder with 0.9% saline or 5% glucose solutions. To date, there is little information about polymyxin stability in different infusions solutions, especially at 40 ºC, a temperature that is recommended to study drug stability as it accelerates degradation reactions. Therefore, in this work an analytical method using LC-MS/MS was developed, validated and applied to determine the stability of polymyxin B diluted in 0.9% saline or 5% glucose solutions at 25 ºC and 40 ºC. The stability of polymyxin B solutions was evaluated during 72 hours. Polymyxin B1 and B2 were stable for 24 hours in saline (0.9%) and glucose solution (5%), however a significant degradation of polymyxin B1 and B2 was observed after 48 hours and 72 hours of assay. The reduction of polymyxin content was evidenced in both saline and glucose media, at room temperature as well as at 40 ºC. No significant differences in pH of polymyxin solutions (glucose or saline) were evidenced during stability assay.

INTRODUÇÃO: Staphylococcus aureus resistentes à meticilina associados à comunidade (CA-MRSA) têm emergido como patógeno em indivíduos sem os tradicionais fatores de risco. MATERIAIS E MÉTODOS: Carreamento nasal de MRSA foi avaliado em indivíduos atendidos em unidade básica de saúde. RESULTADOS: 336 indivíduos foram incluídos: 136 foram testados somente para MRSA e 200 para qualquer S. aureus. Nenhum MRSA foi encontrado nos 336 indivíduos e 23 (11.5%) de 200 eram colonizados por S. aureus. DISCUSSÃO: Baixas taxas de prevalência têm sido encontradas em indivíduos não-hospitalizados, entretanto a vigilância de MRSA é encorajada para o monitoramento da epidemiologia clínica e molecular do CA- MRSA.

INTRODUCTION: Community-associated methicillin-resistant Staphylococcus aureus (MRSA) has emerged as a pathogen in individuals without traditional risk factors. MATERIAL AND METHODS: MRSA nasal carriage was assessed in individuals consulting at a Primary Health Unit in Brazil. RESULTS: A total of 336 individuals were included: 136 were tested only for MRSA and 200 for any S. aureus. No MRSA was found among the 336 individuals and 23 (11.5%) of 200 were colonized by S. aureus. DISCUSSION: Low prevalence rates have been found in non-hospitalized individuals, but MRSA surveillance should be encouraged to monitor clinical and molecular epidemiology of CA- MRSA.

The use of umbilical cord blood stem cells is an efficient alternative for the transplantation of hematopoietic progenitor cells. A number of factors can influence the volume and amount of CD34+ cells, which are considered as immature and capable of proliferation. Quantification of CD34+ cells, evaluation of CD38 and c-kit molecules on these cells, as well as correlations of such factors as maternal age, gestational age, newborn sex and weight, umbilical cord length, placental weight with increased volume and concentration of immature cells, among others, were performed in 70 blood samples from term newborns. The mean volume of umbilical cord blood collected was 53.8±33.6 mL, where 30.96±18.9 CD34+/mL UCB cells were found, of which 16.66±8.32% were CD34+CD38- cells, and 47.23±24.0% were CD34+CD117cells. Newborn weight and placental weight were positively correlated with increased volume of collected UCB. The volume of collected blood was found to affect the absolute count of CD34+ cells and the relative value of these among total nucleated cells, as well as the percentage of CD34+CD117+ and CD34+CD117cells. CD34+ cells were positively correlated with leukocytes, and gestational age was negatively correlated with the number of CD34+ cells. Our results confirm the importance of the accurate quantification of CD34+ cells and their subsets, and that many factors may be related to the higher number of hematopoietic stem cells, which are crucial for successful transplantation.