Asunto(s)
COVID-19 , Fibrinolíticos , Anciano , Fibrinolíticos/uso terapéutico , Hogares para Ancianos , Humanos , Casas de Salud , SARS-CoV-2RESUMEN
BACKGROUND: USA300 is a uniquely successful methicillin-resistant Staphylococcus aureus (MRSA) clone that has been associated with Panton-Valentine leukocidin (PVL) production and severe infections. However, conflicting experimental and epidemiological data exist regarding the virulence of USA300 relative to other MRSA clones. We aimed to address this issue using Drosophila melanogaster as a model host to study strain and PVL-dependent variations in virulence among MRSA clinical isolates. RESULTS: We studied the relative virulence of 39 MRSA isolates: 17 (43%) were PFGE type USA300. Lethal MRSA infection was reproducibly induced both in wild-type (WT) and Toll-deficient D. melanogaster. USA300 strains had significantly lower lethality than non-USA300 strains in a WT background but not in Toll-deficient flies. PFGE type (USA300 versus non-USA300) and PVL status did not affect the response to treatment with linezolid. Virulence was similar in strains with high vancomycin MIC (≥2 µg/mL) versus those with vancomycin MIC<2 µg/mL. CONCLUSIONS: D. melanogaster is a potentially useful model host to study pathogenicity and response to antibiotic treatment in S. aureus. Our results imply that the attenuated virulence of PVL(+)/USA300 requires intact host innate immunity.
Asunto(s)
Acetamidas/administración & dosificación , Antibacterianos/administración & dosificación , Drosophila melanogaster , Staphylococcus aureus Resistente a Meticilina/efectos de los fármacos , Staphylococcus aureus Resistente a Meticilina/patogenicidad , Oxazolidinonas/administración & dosificación , Infecciones Estafilocócicas/tratamiento farmacológico , Animales , Modelos Animales de Enfermedad , Drosophila melanogaster/microbiología , Humanos , Linezolid , Staphylococcus aureus Resistente a Meticilina/fisiología , Infecciones Estafilocócicas/microbiología , Virulencia/efectos de los fármacosRESUMEN
This study used a within-subjects correlational design to determine the relationship between forefoot varus angle and standing rearfoot angle among individuals with above-average forefoot varus angles. Clinicians have long theorized that forefoot position is related to the standing rearfoot angle and that both may be related to pronation during gait. More recently, data suggest that the association between static forefoot and rearfoot position may be limited to those individuals with forefoot varus angles larger or smaller than average. However, little data are available on the association between static forefoot and rearfoot angles among individuals with larger than average forefoot varus angles. Twenty-three healthy participants (mean age = 27.04 +/- 6.24 years) with at least 8 degrees of forefoot varus bilaterally were recruited for this study. Goniometric measurements of forefoot varus angle and standing rearfoot angle of each foot were taken. Intraclass correlation coefficients (ICCs) were used to assess intrarater and interrater reliability of the static forefoot and rearfoot angle measurements. The Pearson product moment coefficient was used to assess the association between the forefoot and rearfoot static angles. ICCs for intrarater and interrater reliability of the forefoot and rearfoot angles were equal to or greater than 0.98 and 0.92, respectively. Forefoot varus angle was significantly correlated with standing rearfoot angle (P = .034). Among healthy individuals with larger than average forefoot varus angles, static forefoot varus and standing rearfoot valgus angles demonstrate a positive association.