RESUMO
Methicillin-resistant Staphylococcus aureus (MRSA) is a risk factor of nosocomial infection with compromised hosts including neonates. Currently, the prevalence of MRSA carriers among children is increasing in Japan. There are some reports of nosocomial infection caused by MRSA in a pediatric ward or neonatal intensive care unit (NICU). During 6 months (from January 2001 to June 2001), 37 MRSA strains were isolated from 37 neonates who were admitted in the NICU and 52 MRSA were strains isolated from NICU environments. We performed DNA typing of MRSA using an arbitrary primed-PCR method on these isolates. Thirty-seven clinical isolates were classified into four types (A type, 14; B type, 4; C type, 4; D type, 3; and others, 12). The A-type strains of MRSA continued to be isolated for more than 6 months. In the NICU environment, the detection rate of the A-type MRSA was 23.1% (12/52). The A-type strains were frequently isolated from environments around patients. The A-type strains of MRSA were prevalent in the NICU, probably due to nosocomial infection. Although none of the neonatal patients developed severe MRSA infection, the same genotype strains were persistently isolated during a period of more than 6 months from patients and the NICU environment around patients. Environmental control around neonatal patients is important to prevent nosocomial infection in the NICU.
Assuntos
Doenças do Prematuro/epidemiologia , Unidades de Terapia Intensiva Neonatal , Resistência a Meticilina , Vigilância da População , Infecções Estafilocócicas/epidemiologia , Staphylococcus aureus/efeitos dos fármacos , Infecção Hospitalar/epidemiologia , Infecção Hospitalar/microbiologia , Meio Ambiente , Humanos , Recém-Nascido , Recém-Nascido Prematuro , Doenças do Prematuro/microbiologia , Reação em Cadeia da Polimerase , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus/genética , Staphylococcus aureus/isolamento & purificaçãoRESUMO
Recently, a few genetic abnormalities were identified in congenital central hypoventilation syndrome (CCHS or Ondine's curse). CCHS is often associated with other neurocristopathies, especially with Hirschsprung's disease (HSCR). Mutations of the genes involved in the receptor tyrosine kinase RET (REarranged during Transfection) (RET)-glial cell line-derived neurotrophic factor (GDNF) and/or endothelin 3 (EDN3)-endothelin receptor-B (EDNRB) signaling pathway have been found in some of HSCR patients. In this study, we analyzed candidates for HSCR, namely the RET, GDNF, EDN3 and EDNRB genes in three isolated CCHS patients to confirm the hypothesis that some CCHS patients have a common genetic abnormality with patients having HSCR or other neurocristopathies. We found a novel R114H mutation of the RET gene in one patient. The R114H mutation is unlikely to be a polymorphism and appears to be associated with CCHS. In addition, we also examined the HOX11L2 (RNX) gene, for which knock-out mice showed CCHS-like syndrome in these isolated CCHS patients and did not detected any mutation. Further cases should be analyzed for more candidates to clarify the pathophysiology of CCHS.
Assuntos
Proteínas de Drosophila , Doença de Hirschsprung/genética , Mutação , Proteínas Proto-Oncogênicas/genética , Receptores Proteína Tirosina Quinases/genética , Apneia do Sono Tipo Central/genética , Animais , Criança , Endotelina-3/genética , Feminino , Fator Neurotrófico Derivado de Linhagem de Célula Glial , Receptores de Fator Neurotrófico Derivado de Linhagem de Célula Glial , Doença de Hirschsprung/complicações , Proteínas de Homeodomínio/genética , Humanos , Lactente , Masculino , Camundongos , Camundongos Knockout , Fatores de Crescimento Neural/genética , Proteínas Oncogênicas/genética , Linhagem , Proteínas Proto-Oncogênicas c-ret , Receptor de Endotelina B , Receptores de Endotelina/genética , Apneia do Sono Tipo Central/complicaçõesRESUMO
Congenital central hypoventilation syndrome (CCHS or Ondine's curse; OMIM 209880) is a disorder characterized by an idiopathic failure of the automatic control of breathing. CCHS is frequently complicated with neurocristopathies such as Hirschsprung's disease (HSCR). The genes involved in the RET-GDNF signaling and/or EDN3-EDNRB signaling pathways have been analyzed as candidates for CCHS; however, only a few patients have mutations of the RET, EDN3, and GDNF genes. Recently, mutations of the PHOX2B gene, especially polyalanine expansions, have been detected in two thirds of patients. We studied the RET, GDNF, GFRA1, PHOX2A, PHOX2B, HASH-1, EDN1, EDN3, EDNRB, and BDNF genes in seven patients with isolated CCHS and three patients with HSCR. We detected polyalanine expansions and a novel frameshift mutation of the PHOX2B gene in four patients and one patient, respectively. We also found several mutations of the RET, GFRA1, PHOX2A, and HASH-1 genes in patients with or without mutations of the PHOX2B gene. Our study confirmed the prominent role of mutations in the PHOX2B gene in the pathogenesis of CCHS. Mutations of the RET, GFRA1, PHOX2A, and HASH-1 genes may also be involved in the pathogenesis of CCHS. To make clear the pathogenesis of CCHS, the analysis of more cases and further candidates concerned with the development of the autonomic nervous system is required.