RESUMEN
OBJECTIVES: The prevalence of methicillin-resistant Staphylococcus aureus (MRSA) in cystic fibrosis (CF) patients in the United States is approximately 25%. Little is known about the relative proportion of hospital- versus community-associated strains or the antimicrobial susceptibility of MRSA in different CF centers. We hypothesized that the majority of MRSA isolates obtained from children with CF are those endemic in the hospital and that those associated with community acquisition (SCCmec IV) would be more resistant than typically seen in non-CF MRSA isolates. METHODS: We studied MRSA strains from seven pediatric CF centers to determine the clonal distribution based on DNA sequencing of the staphylococcal protein A gene (spa typing), the type of staphylococcal chromosomal cassette mec (SCCmec), and the proportion of strains with Panton-Valentine leukocidin (PVL). Antimicrobial susceptibility to systemic and topical antibiotics was compared between different MRSA types. RESULTS: We analyzed 277 MRSA isolates from unique patients (mean age 11.15 ± 4.77 years, 55% male). Seventy % of isolates were SCCmec II PVL negative and the remainder SCCmec IV. Overall 17% MRSA strains were PVL positive (all SCCmec IV). Spa typing of 118 isolates showed most of the SCCmec II strains being t002, while SCCmec IV PVL positive isolates were t008, and SCCmec IV PVL negative isolates represented a variety of spa-types. The proportions of SCCmec II strains and spa-types were similar among centers. Overall rates of resistance to trimethoprim-sulfamethoxazole (4%), tetracycline (7%), tigecycline (0.4%), linezolid (0.4%) as well as fosfomycin (0.4%), fusidic acid (3%), and mupirocin (1%) were low. No strains were resistant to vancomycin. SCCmec II strains had higher rates of resistance to ciprofloxacin and clindamycin (P < 0.001) than SCCmec IV strains. CONCLUSIONS: In this U.S. study, most MRSA isolates in the pediatric CF population were SCCmec II PVL negative. Rates of resistance were low, including to older and orally available antibiotics such as trimethoprim-sulfamethoxazole.
Asunto(s)
Antibacterianos/farmacología , Fibrosis Quística/microbiología , ADN Bacteriano/genética , Staphylococcus aureus Resistente a Meticilina/genética , Neumonía Estafilocócica/microbiología , Acetamidas/farmacología , Adolescente , Proteínas Bacterianas/genética , Toxinas Bacterianas/genética , Broncoscopía , Niño , Preescolar , Estudios de Cohortes , Fibrosis Quística/complicaciones , Exotoxinas/genética , Femenino , Fosfomicina/farmacología , Ácido Fusídico/farmacología , Humanos , Leucocidinas/genética , Linezolid , Masculino , Staphylococcus aureus Resistente a Meticilina/efectos de los fármacos , Pruebas de Sensibilidad Microbiana , Minociclina/análogos & derivados , Minociclina/farmacología , Tipificación Molecular , Mupirocina/farmacología , Oxazolidinonas/farmacología , Proteínas de Unión a las Penicilinas , Faringe/microbiología , Neumonía Estafilocócica/complicaciones , Análisis de Secuencia de ADN , Esputo/microbiología , Infecciones Estafilocócicas/complicaciones , Infecciones Estafilocócicas/tratamiento farmacológico , Infecciones Estafilocócicas/microbiología , Proteína Estafilocócica A/genética , Tetraciclina/farmacología , Tigeciclina , Combinación Trimetoprim y Sulfametoxazol/farmacología , Estados UnidosRESUMEN
There are few reports of cystic fibrosis (CF) diagnosed in premature infants. We describe the clinical course of three patients, from our neonatal intensive care units, who were diagnosed with CF, and discuss the existing literature and treatment considerations.
Asunto(s)
Causas de Muerte , Fibrosis Quística/diagnóstico , Enfermedades del Prematuro/diagnóstico , Recien Nacido Prematuro , Terapia Combinada , Fibrosis Quística/mortalidad , Fibrosis Quística/terapia , Femenino , Humanos , Recién Nacido , Enfermedades del Prematuro/mortalidad , Enfermedades del Prematuro/terapia , Unidades de Cuidado Intensivo Neonatal , Masculino , Medición de Riesgo , Muestreo , Índice de Severidad de la Enfermedad , Tasa de SupervivenciaRESUMEN
BACKGROUND: Anaerobic bacteria are increasingly regarded as important in cystic fibrosis (CF) pulmonary infection. The aim of this study was to determine the effect of antibiotic treatment on aerobic and anaerobic microbial community diversity and abundance during exacerbations in patients with CF. METHODS: Sputum was collected at the start and completion of antibiotic treatment of exacerbations and when clinically stable. Bacteria were quantified and identified following culture, and community composition was also examined using culture-independent methods. RESULTS: Pseudomonas aeruginosa or Burkholderia cepacia complex were detected by culture in 24/26 samples at the start of treatment, 22/26 samples at completion of treatment and 11/13 stable samples. Anaerobic bacteria were detected in all start of treatment and stable samples and in 23/26 completion of treatment samples. Molecular analysis showed greater bacterial diversity within sputum samples than was detected by culture; there was reasonably good agreement between the methods for the presence or absence of aerobic bacteria such as P aeruginosa (κ=0.74) and B cepacia complex (κ=0.92), but agreement was poorer for anaerobes. Both methods showed that the composition of the bacterial community varied between patients but remained relatively stable in most individuals despite treatment. Bacterial abundance decreased transiently following treatment, with this effect more evident for aerobes (median decrease in total viable count 2.3×10(7) cfu/g, p=0.005) than for anaerobes (median decrease in total viable count 3×10(6) cfu/g, p=0.046). CONCLUSION: Antibiotic treatment targeted against aerobes had a minimal effect on abundance of anaerobes and community composition, with both culture and molecular detection methods required for comprehensive characterisation of the microbial community in the CF lung. Further studies are required to determine the clinical significance of and optimal treatment for these newly identified bacteria.
Asunto(s)
Antibacterianos/farmacología , Bacterias/efectos de los fármacos , Infecciones Bacterianas/tratamiento farmacológico , Fibrosis Quística/microbiología , Infecciones Oportunistas/tratamiento farmacológico , Adolescente , Adulto , Antibacterianos/uso terapéutico , Bacterias/clasificación , Bacterias/aislamiento & purificación , Bacterias Aerobias/clasificación , Bacterias Aerobias/efectos de los fármacos , Bacterias Aerobias/aislamiento & purificación , Bacterias Anaerobias/clasificación , Bacterias Anaerobias/efectos de los fármacos , Bacterias Anaerobias/aislamiento & purificación , Infecciones Bacterianas/complicaciones , Recuento de Colonia Microbiana , Fibrosis Quística/complicaciones , Fibrosis Quística/fisiopatología , Femenino , Volumen Espiratorio Forzado , Humanos , Masculino , Infecciones Oportunistas/complicaciones , Polimorfismo de Longitud del Fragmento de Restricción , Esputo/microbiología , Adulto JovenRESUMEN
We pseudotyped HIV-1 vectors with cytoplasmic tail-truncated envelope glycoproteins of a wild-type (WT) measles virus (MV). The particles entered the lymphatic cells exclusively through the signaling lymphocyte activation molecule (SLAM, CD150), whereas particles pseudotyped with the MV vaccine strain glycoproteins also recognized the ubiquitous membrane cofactor protein (CD46) as receptor and had less specific cell entry. MV(WT)-HIV vectors reached titers of 10(8) t.u. ml(-1), which were up to 10-fold higher than those of MV(Vac)-HIV vectors, and discriminated between SLAM-positive and SLAM-negative cells, also in mixed cell cultures. As these vectors transduce primary human cells more efficiently than vesicular stomatitis virus-G pseudotyped vectors do, they are promising candidates for gene transfer to human lymphocytes and certain epithelial cells.
Asunto(s)
Vectores Genéticos/genética , VIH-1/genética , Lentivirus/genética , Virus del Sarampión/genética , Proteínas del Envoltorio Viral/genética , Linfocitos B/virología , Línea Celular , Células Epiteliales/virología , Marcación de Gen/métodos , VIH-1/fisiología , Humanos , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Proteína Asociada a la Molécula de Señalización de la Activación Linfocitaria , Transfección , Tropismo Viral/genética , Internalización del VirusRESUMEN
An association between mannan-binding lectin (MBL) status and severity of lung function impairment in cystic fibrosis (CF) has been found in several studies, but not in others. To explore the possible basis for discrepancies in the literature, we related both MBL and L-ficolin concentrations to lung function and examined the results in relation to the age of the patients. For patients under 15 years of age, those with MBL < 200 ng/ml had better lung function than those with MBL > 200 ng/ml [median forced expiratory volume in 1 s (FEV(1)), 99% versus 83%; P = 0.05]. For patients over 15 years of age, those with MBL < 200 ng/ml had poorer lung function than those with MBL > 200 ng/ml (median FEV(1), 44% versus 55%; P = 0.1). Also, for the over 15-year-olds, the proportion of patients with FEV(1) values below the median was greater in the MBL-insufficient subgroup (P < 0.04). In other words, relative deficiency of MBL appears to accelerate the age-related decline in lung function in CF patients. No corresponding relationships could be found between L-ficolin concentration and lung function. These findings and interpretation lend support to the potential value of MBL replacement therapy in a small minority of cystic fibrosis patients.
Asunto(s)
Envejecimiento/fisiología , Fibrosis Quística/fisiopatología , Pulmón/fisiopatología , Lectina de Unión a Manosa/metabolismo , Adolescente , Adulto , Niño , Preescolar , Fibrosis Quística/metabolismo , Ensayo de Inmunoadsorción Enzimática , Femenino , Volumen Espiratorio Forzado , Humanos , Lactante , Lectinas/análisis , Lectinas/metabolismo , Pulmón/metabolismo , Masculino , Oportunidad Relativa , Estadísticas no Paramétricas , FicolinasRESUMEN
The improvement of gene transfer efficiency in growth-arrested cells using human immunodeficiency virus type 1 (HIV-1)-derived vectors led to the development of vectors derived from other members of the lentivirus family. Here we report the generation of a lentiviral vector derived from the apathogenic molecular virus clone SIVagm3mc of the simian immunodeficiency virus from African green monkeys (Cercocebus pygerythrus). Upon pseudotyping with the G-protein of vesicular stomatitis virus (VSV-G), the SIVagm-derived vector was shown to transduce proliferating and growth-arrested mammalian cell lines, including human cells. After in vivo inoculation into the striatum of the adult rat brain, the vector was shown to transduce terminally differentiated neurons and oligodendrocytes as well as quiescent and reactive astrocytes. Moreover, SIVagm transfer vector mRNA was efficiently packaged by HIV-1 vector particles. Homologous [SIV(SIV)] vectors generated by using the SIVagm-derived envelope glycoproteins allowed selective gene transfer into human CD4(+)/CCR5(+) cells. Thus, the SIVagm3mc-derived vector is a useful alternative to HIV-1-derived lentiviral vectors in somatic gene therapy.
Asunto(s)
Vectores Genéticos , Glicoproteínas de Membrana , Virus de la Inmunodeficiencia de los Simios , Animales , Linfocitos T CD4-Positivos , División Celular , Línea Celular Transformada , Femenino , Genes env , Vectores Genéticos/genética , VIH-1/genética , Humanos , Lentivirus/genética , Neuroglía , Neuronas , Ratas , Ratas Endogámicas F344 , Virus de la Inmunodeficiencia de los Simios/genética , Virus de la Inmunodeficiencia de los Simios/patogenicidad , Transducción Genética , Virus de la Estomatitis Vesicular Indiana/genética , Proteínas del Envoltorio Viral/genética , ViriónRESUMEN
The presence of lipids in alveolar macrophages has been used clinically as an indicator of aspiration, a process associated with increased lung inflammation in animal models. The hypothesis is that the quantity of lipids in alveolar macrophages, measured as lipid-laden index (LLI), would correlate with lung inflammation in paediatric patients. Children with chronic respiratory symptoms (21 cystic fibrosis (CF), 24 non-CF) underwent flexible bronchoscopy with bronchoalveolar lavage (BAL) and 24-h intraoesophageal pH monitoring for clinical indications. Total cell counts, number and per cent of neutrophils and macrophages, and LLI were determined in the bronchoalveolar lavage fluids (BALF) from all children. BALF were also obtained from eight healthy, young nonsmoking adults for comparison. LLI in non-CF children were 6.9 +/- 3.5 (mean +/- SEM) which were higher than LLI in healthy adults (1.0 +/- 0.4), (p=0.045). Children with CF had very high LLIs (19.2 +/- 4.5) compared with both healthy adults (p=0.014) and children without CF (p=0.045). LLI did not correlate with airway inflammation in any group. LLI in children with abnormal pH probes had a tendency to be higher than in children with normal pH probes, but the difference was not significant (p=0.098). It is concluded that the lipid-laden index was significantly elevated in children with chronic respiratory symptoms compared with healthy adults, and in children with cystic fibrosis compared with those who have other chronic respiratory conditions. However, the lipid-laden index did not correlate with the quantity of bronchoalveolar lavage fluid inflammation. The lipid-laden index in children may, in part, reflect processes other than aspiration, such as airways obstruction.
Asunto(s)
Líquido del Lavado Bronquioalveolar/química , Fibrosis Quística/fisiopatología , Lípidos/análisis , Macrófagos Alveolares/química , Enfermedades Respiratorias/fisiopatología , Líquido del Lavado Bronquioalveolar/citología , Broncoscopía , Recuento de Células , Enfermedad Crónica , Humanos , Inflamación/fisiopatologíaRESUMEN
Recent studies suggest that inflammation plays a role in the pathogenesis of lung disease in cystic fibrosis (CF). The goal of the present study was to quantitatively compare bronchoalveolar lavage fluid (BALF) inflammation and its relation to bacterial infection, between children with CF and children with other chronic respiratory problems. Differential cell counts, immunoreactive interleukin 8 (IL-8), and quantitative bacterial cultures were done in BALF from 54 CF (median age 1.8 yr) and 55 control patients (median age 1.0 yr) who underwent bronchoscopy for clinical indications. Among infected CF patients, those with Pseudomonas aeruginosa did not have more inflammation than those without P. aeruginosa. The ratio of neutrophils or of IL-8 to bacteria in BALF was significantly greater for CF patients compared with control subjects, regardless of pathogen. Calculation of linear regression for either neutrophils or IL-8, as a function of bacterial quantity, yielded positive slopes for both CF and control patients, but with significant elevations for CF. We conclude that the inflammatory response to bacterial infection is increased or prolonged in CF compared with control patients, and that this increase is not necessarily due to pathogens specific for CF (e.g., P. aeruginosa). These data may provide further rationale for anti-inflammatory therapy early in CF.