Browsing by Author "Faustino, MA"
Now showing 1 - 4 of 4
Results Per Page
Sort Options
- Characterization and genome sequencing of a Citrobacter freundii phage CfP1 harboring a lysin active against multidrug-resistant isolatesPublication . Oliveira, H; Pinto, G; Oliveira, A; Oliveira, C; Faustino, MA; Briers, Y; Domingues, L; Azeredo, JCitrobacter spp., although frequently ignored, is emerging as an important nosocomial bacterium able to cause various superficial and systemic life-threatening infections. Considered to be hard-to-treat bacterium due to its pattern of high antibiotic resistance, it is important to develop effective measures for early and efficient therapy. In this study, the first myovirus (vB_CfrM_CfP1) lytic for Citrobacter freundii was microbiologically and genomically characterized. Its morphology, activity spectrum, burst size, and biophysical stability spectrum were determined. CfP1 specifically infects C. freundii, has broad host range (>85 %; 21 strains tested), a burst size of 45 PFU/cell, and is very stable under different temperatures (-20 to 50 °C) and pH (3 to 11) values. CfP1 demonstrated to be highly virulent against multidrug-resistant clinical isolates up to 12 antibiotics, including penicillins, cephalosporins, carbapenems, and fluroquinoles. Genomically, CfP1 has a dsDNA molecule with 180,219 bp with average GC content of 43.1 % and codes for 273 CDSs. The genome architecture is organized into function-specific gene clusters typical for tailed phages, sharing 46 to 94 % nucleotide identity to other Citrobacter phages. The lysin gene encoding a predicted D-Ala-D-Ala carboxypeptidase was also cloned and expressed in Escherichia coli and its activity evaluated in terms of pH, ionic strength, and temperature. The lysine optimum activity was reached at 20 mM HEPES, pH 7 at 37 °C, and was able to significantly reduce all C. freundii (>2 logs) as well as Citrobacter koseri (>4 logs) strains tested. Interestingly, the antimicrobial activity of this enzyme was performed without the need of pretreatment with outer membrane-destabilizing agents. These results indicate that CfP1 lysin is a good candidate to control problematic Citrobacter infections, for which current antibiotics are no longer effective.
- Determinantes da colonização materna e da infecção neonatal por Streptococcus do grupo BPublication . Areal, A; Moreira, M; Nunes, S; Faustino, MA; Cardoso, L; Sá, CAim and Objective: During the past three decades, group B Streptococcus (GBS) neonatal infection has been the subject of little research. The aim of this study was to evaluate the association between maternal risk factors, as established by the Center for Disease Control and Prevention (CDC), and maternal colonization. We also analysed the association between risk factors present in newborns and early-onset GBS disease. Study design: Cross-sectional study. Population: All pregnant women admitted for delivery in our institution and their newborns, between 1st February and 31st July 2005. Methods: Maternal and neonatal characteristics were collected from hospital clinical data, including information on risk factors established by the CDC. Descriptive statistics was used to characterize the study sample. Qui-square and Mantel-haenszel tests were applied to compare proportions and to measure the strength of associations, respectively, setting significance at p < 0,05. Results: In this sample only 47% of women were screened for GBS colonization in suitable time and 34,9% of these women were colonized. The incidence of early neonatal infection by SGB was 9/1000 neonates. Significant associations between GBS maternal colonization ant the following parameters were observed: maternal age [p=0,012; OR=1,659 (IC a 95%, 1,218-2,260)], gestational age at labour [p=0,001; OR= 2,621 (IC a 95%, 1,641- 4,188)], and urinary GBS infection during pregnancy (p<0,001). Maternal colonization occurred in women without CDC defined risk factors. Early neonatal infection by SGB was strongly associated with unscreened women (p=0,014). Conclusion: In this study, maternal GBS colonization occurred in the absence of CDC defined risk factors and varied according to maternal age and gestational week. Neonatal GBS infection was more frequent in unscreened women.
- Group B streptococcal colonisation in pregnant women: turnaround time of three culture methodsPublication . Areal, A; Faustino, MA
- A infecção peri-natal por Streptococcus agalactiae pode ser evitada: prevalência da colonização em parturientes no Hospital de S. Marcos, factores de risco e sua relação com a infecção peri-natalPublication . Areal, A; Nunes, S; Moreira, M; Faustino, MA; Cardoso, L; Sá, Cntrodução: O Streptococcus agalactiae (SGB) é o agente mais frequente de infecção neonatal precoce, sendo possível a sua prevenção. Em Portugal é desconhecida a prevalência de mulheres colonizadas por SGB. O estudo da Unidade de Vigilância Pediátrica refere uma prevalência nacional de infecção neonatal por SGB de 0,5:1000 nados-vivos. Objectivo: Determinar a prevalência da colonização materna e da infecção perinatal por SGB no Hospital de S. Marcos, Braga (HSM), de modo a avaliar a importância da implementação do rastreio universal e o uso de medidas profiláticas. Método: De 1 de fevereiro a 31 de julho de 2005 foi realizado um estudo transversal com análise de coortes anichada, avaliando todas as grávidas assistidas para trabalho de parto no HSM e respectivos recém-nascidos. Os dados foram submetidos a análise estatística bi-variada pelo teste do qui-quadrado, com um nível de significância de 5% (p<0,05). Resultados: A prevalência da colonização nas grávidas rastreadas na região de Braga foi de 34,9 % [intervalo de confiança a 95% (IC95%), 31,5-38,3%]. No HSM o diagnóstico de infecção neonatal precoce por SGB ocorreu em 9:1000 recém-nascidos. O risco relativo de ocorrência de infecção perinatal entre os recém-nascidos dos grupos de mães rastreadas e não rastreadas foi de 0,3 [IC95% 0,2,7-0,32]. Conclusão: O rastreio bacteriológico positivo para colonização materna por SGB associado à adequada profilaxia intra-parto reduziu significativamente a infecção neonatal precoce, em relação ao grupo de gestantes não rastreadas (p=0,014). Consideramos que é recomendável a instituição do rastreio universal das grávidas e a profilaxia adequada quando indicada.