RESUMO
The phenotypic and genotypic characteristics of Staphylococcus aureus strains isolated from respiratory tract of cystic fibrosis (CF) patients were investigated. Slime production, cell-surface hydrophobicity, type of capsular polysaccharide, profile of heteroresistance to methicillin and Sma I restriction profiles were evaluated. S. aureus CF strains have been shown to be heterogeneous in respect to several important features. All of them were slime producing with variation in colony morphology. High or moderate cell-surface hydrophobicity (CSH) was found for, respectively, 16.2% and 83.8% strains. Thirty strains were resistant to methicillin, 60% of them showed heteroresitance and 40% were homoresistant. It was found that 59.6% of strains produced capsular polysaccharides (CP) of 5 or 8 type. Among CP5/CP8 strains, CP8 was the predominant type (81.1%). Typing of 62 CF strains by macrorestriction analysis of chromosomal DNA revealed several major types, differing in their SmaI profiles with a similarity coefficient lower than 0.4. Some of the strains isolated from the same patient at different times of hospitalization, as well as strains isolated at the same time from the relatives, were identical in their PFGE pattern.
Assuntos
Fibrose Cística/complicações , Infecções Estafilocócicas/complicações , Staphylococcus aureus/classificação , Adolescente , Adulto , Criança , Pré-Escolar , Fibrose Cística/microbiologia , DNA Bacteriano/química , DNA Bacteriano/genética , Desoxirribonucleases de Sítio Específico do Tipo II/química , Eletroforese em Gel de Campo Pulsado , Ensaio de Imunoadsorção Enzimática , Humanos , Lactente , Resistência a Meticilina/genética , Filogenia , Polissacarídeos Bacterianos/análise , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus/genética , Staphylococcus aureus/isolamento & purificação , Propriedades de SuperfícieRESUMO
The goal of this study is to assess the association of HLA-DQ alleles with the age of onset of type 1 diabetes in African American patients. Using PCR oligonucleotide typing, HLA-DQA1 and DQB1 alleles were determined. DQA1*0301, DQB1*0201, and DQB1*0302 were significantly increased in African American patients. However, the DQB1*0602 allele was decreased in these patients. In addition, DQA1*0401 and DQB1*0402, were associated with protection in African Americans. When stratified by age of onset, prepubertal patients showed an absence of the protective allele DQB1*0602 and a significant increase in DQB1*0201 compared to postpubertal patients. The high frequency of the HLA-DQ susceptibility allele in pre-pubertal patients suggest that the biology of disease in this group may differ from type 1 diabetes with a later age of onset.
