RESUMEN
2009 H1N1 pandemic influenza was associated with increased risk for severe disease in children and the immunosuppressed. We report a case of uncomplicated pneumonia because of infection with oseltamivir-resistant 2009 H1N1 virus in an immunosuppressed pediatric renal transplant patient. Innate immunity and/or altered viral fitness may be responsible for the mild clinical phenotype of the case.
Asunto(s)
Antivirales/uso terapéutico , Farmacorresistencia Viral , Subtipo H1N1 del Virus de la Influenza A/efectos de los fármacos , Gripe Humana/inmunología , Oseltamivir/uso terapéutico , Neumonía Viral/inmunología , Complicaciones Posoperatorias/inmunología , Antivirales/farmacología , Niño , Femenino , Humanos , Huésped Inmunocomprometido , Subtipo H1N1 del Virus de la Influenza A/aislamiento & purificación , Gripe Humana/diagnóstico , Gripe Humana/tratamiento farmacológico , Gripe Humana/virología , Trasplante de Riñón , Oseltamivir/farmacología , Neumonía Viral/diagnóstico , Neumonía Viral/tratamiento farmacológico , Neumonía Viral/virología , Complicaciones Posoperatorias/diagnóstico , Complicaciones Posoperatorias/tratamiento farmacológico , Complicaciones Posoperatorias/virologíaRESUMEN
Members of the Streptococcus bovis group are important causes of endocarditis. However, factors associated with their pathogenicity, such as adhesins, remain uncharacterized. We recently demonstrated that endocarditis-derived Streptococcus gallolyticus subsp. gallolyticus isolates frequently adhere to extracellular matrix (ECM) proteins. Here, we generated a draft genome sequence of an ECM protein-adherent S. gallolyticus subsp. gallolyticus strain and found, by genome-wide analyses, 11 predicted LPXTG-type cell wall-anchored proteins with characteristics of MSCRAMMs, including a modular architecture of domains predicted to adopt immunoglobulin (Ig)-like folding. A recombinant segment of one of these, Acb, showed high-affinity binding to immobilized collagen, and cell surface expression of Acb correlated with the presence of acb and collagen adherence of isolates. Three of the 11 proteins have similarities to major pilus subunits and are organized in separate clusters, each including a second Ig-fold-containing MSCRAMM and a class C sortase, suggesting that the sequenced strain encodes three distinct types of pili. Reverse transcription-PCR demonstrated that all three genes of one cluster, acb-sbs7-srtC1, are cotranscribed, consistent with pilus operons of other gram-positive bacteria. Further analysis detected expression of all 11 genes in cells grown to mid to late exponential growth phases. Wide distribution of 9 of the 11 genes was observed among S. gallolyticus subsp. gallolyticus isolates with fewer genes present in other S. bovis group species/subspecies. The high prevalence of genes encoding putative MSCRAMMs and pili, including a collagen-binding MSCRAMM, among S. gallolyticus subsp. gallolyticus isolates may play an important role in the predominance of this subspecies in S. bovis endocarditis.
Asunto(s)
Adhesinas Bacterianas/metabolismo , Fimbrias Bacterianas/metabolismo , Regulación Bacteriana de la Expresión Génica/fisiología , Streptococcus/metabolismo , Perfilación de la Expresión Génica , Genoma Bacteriano , Familia de Multigenes , Streptococcus/clasificación , Streptococcus/genéticaRESUMEN
Members of the Streptococcus bovis group are frequent colonizers of the intestinal tract, which can also cause endocarditis. However, their ability to adhere to and colonize host tissues and the factors associated with pathogenicity are largely unknown. Here, we assessed 17 endocarditis-derived human isolates [identified here as 15 Streptococcus gallolyticus ssp. gallolyticus (S. bovis biotype I), one S. gallolyticus ssp. pasteurianus (biotype II/2) and one Streptococcus infantarius ssp. coli (biotype II/1)] for their in vitro adherence to components of the extracellular matrix (ECM). Adherence to collagen type I was found to be the most common phenotype exhibited by 76% of isolates, followed by collagen type IV (53%), fibrinogen (47%), collagen type V (35%) and fibronectin (35%). Pulsed-field gel electrophoresis analyses showed that >50% of endocarditis-derived S. gallolyticus ssp. gallolyticus isolates are genetically diverse, although two clusters of two and four isolates were observed. The diversity of strains and differences observed in adherence characteristics to distinct host ECM proteins suggest that isolates of S. gallolyticus ssp. gallolyticus produce different surface components, similar to other gram-positive pathogens, to colonize the host and cause infection.
Asunto(s)
Adhesión Bacteriana , Endocarditis Bacteriana/microbiología , Proteínas de la Matriz Extracelular/fisiología , Interacciones Huésped-Patógeno , Streptococcus bovis/clasificación , Streptococcus bovis/fisiología , Animales , Colágeno/química , Colágeno/fisiología , Electroforesis en Gel de Campo Pulsado , Proteínas de la Matriz Extracelular/química , Fibronectinas/química , Fibronectinas/fisiología , Humanos , Ratas , Infecciones Estreptocócicas/microbiología , Streptococcus bovis/aislamiento & purificación , Streptococcus bovis/patogenicidadRESUMEN
We reevaluated Enterobacteriaceae disk diffusion breakpoints for the tetracyclines published in the Clinical and Laboratory Standards Institute (CLSI) document M100-S16, which were (susceptible/resistant) >or=19 mm/Asunto(s)
Antibacterianos/farmacología
, Pruebas Antimicrobianas de Difusión por Disco/normas
, Farmacorresistencia Bacteriana
, Enterobacteriaceae/efectos de los fármacos
, Tetraciclinas/farmacología
, Laboratorios/normas
RESUMEN
Streptococcus bovis causes 24% of all streptococcal infective endocarditis cases. There are many reports linking both S. bovis bacteremia and endocarditis with various forms of gastrointestinal disease (primarily colonic cancers). S. bovis is divided into two biotypes: I and II. The biotype I strain is much more frequently isolated from patients with endocarditis, gastrointestinal disease, or both. We describe here the isolation of biotype I-specific DNA sequences and the development of a PCR test which can identify S. bovis biotype I strains among S. bovis clinical isolates.