ABSTRACT
Burkholderia cepacia complex isolates obtained by microbiological culture of respiratory samples from Brazilian CF patients were studied by recA based PCR, screened by specific PCR for virulence markers and genotyped by RAPD. Forty-one isolates of B. cepacia complex were identified by culture and confirmation of identity and genomovar determination obtained in 32 isolates, with predominance of B. cenocepacia (53.1%). Virulence markers were not consistently found among isolates. Genotyping did not identify identical patterns among different patients. B. cenocepacia was the most prevalent B. cepacia complex member among our patients, and cross-infection does not seem to occur among them.
Subject(s)
Burkholderia Infections/genetics , Burkholderia cepacia complex/genetics , Burkholderia cepacia complex/isolation & purification , Cystic Fibrosis/microbiology , Brazil/epidemiology , Burkholderia Infections/epidemiology , Cohort Studies , Genotype , Humans , Prevalence , Rec A Recombinases/genetics , Virulence/geneticsABSTRACT
S. maltophilia, A. xylosoxidans subsp. xylosoxidans (Ax) e complexo B. cepacia (Bc) têm sido freqüentemente encontrados colonizando/infectando pacientes com fibrose cística (FC). Pouco se sabe sobre a patogenicidade desses microrganismos. Os objetivos desse trabalho foram identificar, analisar genotipicamente e estudar possíveis fatores de virulência desses microrganismos. Foram utilizados métodos fenotípicos clássicos e moleculares (PCR, RAPD e/ou seqüenciamento) para a identificação, PFGE para a tipagem genotípica e realizado o estudo da capacidade de adesão desses microrganismos às células MRC-5. Foram pesquisadas a produção de fímbria SMF-1 e elastase por S. maltophilia e a presença de anticorpos anti SMF-1 em pacientes colonizados/infectados por S. maltophilia. Foram coletadas 415 amostras do trato respiratório de 113 pacientes, atendidos no Instituto da Criança (HC-FMUSP) de jun/2003 a jun/2004, e isoladas 23 S. maltophilia, 23 Bc, 17 Ax e 5 B. gladioli de 35 pacientes. As amostras de S. maltophilia apresentaram 14 perfis genotípicos, sendo detectado o mesmo perfil em amostras obtidas de 2 pacientes. 95,2% das cepas foram produtoras de elastase. Todas as cepas apresentaram adesão às células e ao plástico. Foram detectados a produção de fímbrias SMF-1 por S. maltophilia e anticorpos anti SMF-1 no soro dos pacientes infectados/colonizados por S. maltophilia. As amostras do Bc apresentaram 12 perfis no PFGE e as de B. gladioli 2 perfis. Não foram compartilhados perfis idênticos entre pacientes diferentes. A maior parte das cepas aderiu fracamente às células MRC-5. As amostras de Ax apresentaram 7 perfis genotípicos, sendo que dois perfis foram encontrados em 6 pacientes. Apenas 7/17 amostras apresentaram adesão às células. Em conclusão, não houve transmissão cruzada ou por fonte comum entre os pacientes infectados/colonizados por Bc o que não se pode descartar nos pacientes em que foram isolados Ax e S. maltophilia. Os ...
Subject(s)
Achromobacter denitrificans , Burkholderia cepacia complex , Cystic Fibrosis , Genetic Variation , Stenotrophomonas maltophilia , Virulence FactorsABSTRACT
BACKGROUND: Early diagnosis of Pseudomonas aeruginosa colonization/infection in patients with cystic fibrosis (CF) using microbiological culturing methods may be difficult. Serology and polymerase chain reaction (PCR) may be useful techniques for early detection of P. aeruginosa in children with CF. METHODS: A cross-sectional analysis comparing results obtained by three different methods for P. aeruginosa identification was performed in 87 CF patients with a mean age of 9.7 years. Microbiological culturing and PCR targeting the algD GDP mannose dehydrogenase gene of P. aeruginosa were performed in sputum or oropharyngeal swabs samples, and serum antibodies against three P. aeruginosa antigens (elastase, alkaline protease, and exotoxin A) were assessed once. RESULTS: It was possible to isolate P. aeruginosa by culture in samples from 42 patients (48.2%), while PCR was positive in 53 (60.9%) patients. Serology was positive in 38 patients (43.6%), with a higher positivity for elastase (37.9%), followed by alkaline protease (29.9%) and exotoxin A (19.5%). The difference among the three isolated methods was not statistically significant. The combination of PCR + serology was significantly superior to single methods, to PCR + culture and also to culture + serology. CONCLUSIONS: PCR identified a higher number of patients with P. aeruginosa than serology and conventional culture, but the difference did not reach statistical significance. Any of the combination methods that included PCR resulted in significantly statistical differences in relation to isolated microbiological or serology methods, but not to the PCR method alone, suggesting that PCR may be the main additive method for P. aeruginosa identification.
