RESUMEN
Urinary tract infection (UTI) and bloodstream infection (BSI) caused by extended-spectrum ß-lactamase (ESBL)-producing bacteria are important healthcare problems. Appropriate infection management requires the direct detection of organisms in clinical specimens. We assessed the capability of the matrix-assisted laser desorption/ionization time-of-flight mass spectrometry-based MBT STAR-Cepha kit to detect ESBL producers in clinical urine and blood samples. Over a 1-year period, 90 urine samples and 55 positive monomicrobial (Escherichia coli, Klebsiella pneumoniae, Klebsiella oxytoca, or Proteus mirabilis) blood cultures were collected from patients with UTI or BSI at Hamamatsu University Hospital. ß-lactamase activity in these samples was directly detected using the MBT STAR-Cepha kit, and the results were compared with those of antimicrobial susceptibility testing and polymerase chain reaction detection assay for the isolates. In receiver operating characteristic curve analysis, the kit assay showed low accuracy in detecting ESBL producers in urine samples (area under the curve [AUC], 0.69). Meanwhile, the AUC for detecting all ESBL-producing bacteria in positive blood cultures was 0.81. The kit assay detected cefotaxime (CTX) resistance (mainly in CTX-M-type ESBL producers) with high accuracy in positive blood cultures; however, it did not accurately detect ESBL producers in urine samples and CTX-susceptible isolates with other ESBL-associated genes (e.g., TEM and SHV types) in positive blood cultures. MBT STAR-Cepha testing can accurately discriminate CTX-resistant ESBL producers in BSI cases and thus can contribute to effective infection management. The results suggest that different sample types, antibiotic resistance profiles, and resistance genes can affect the kit performance.
Asunto(s)
Infecciones Urinarias , beta-Lactamasas , Humanos , beta-Lactamasas/genética , beta-Lactamasas/análisis , Cultivo de Sangre , Cefotaxima , Escherichia coli , Klebsiella pneumoniae , Espectrometría de Masas , Infecciones Urinarias/diagnóstico , Infecciones Urinarias/microbiología , Rayos Láser , Pruebas de Sensibilidad Microbiana , Antibacterianos/farmacologíaRESUMEN
Rapid and simple detection of extended-spectrum ß-lactamase (ESBL) and carbapenemase is essential for antimicrobial treatment and infection control. Recently, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS)-based MBT STAR-Cepha and MBT STAR-Carba kits have been developed with simplified MBT STAR-BL operations. However, the utility of these kits has not been fully examined in clinical microbiology laboratories. In this study, we evaluated the utility of MALDI-TOF MS-based MBT STAR-Cepha and MBT STAR-Carba kits to detect ESBL and carbapenemase-producing bacteria, and compared it with the conventional broth microdilution test and PCR amplification assay. We found that the MBT STAR-Cepha kit efficiently distinguished resistant strains of third-generation cephalosporin susceptibility phenotypes and non-SHV-type ESBL producers. In the receiver operating characteristic analysis, the area under the receiver operating characteristic curve (AUC) for detecting third-generation cephalosporin resistance using the MBT STAR-Cepha kit was 0.97-1.00, but the AUC for detecting ESBL producers was 0.64. In addition, we showed that the MBT STAR-Carba kit enabled the accurate detection of antimicrobial resistance by IMP-type carbapenemase producers. The AUC for detecting carbapenemase producers was 1.00. The results suggested that the target bacterial strains, antimicrobial susceptibility phenotypes, and resistance genes were important for the utility of the MALDI-TOF MS-based MBT STAR-Cepha and MBT STAR-Carba kits in bacterial routine diagnostics.
Asunto(s)
Bacterias/aislamiento & purificación , Proteínas Bacterianas/metabolismo , Técnicas de Tipificación Bacteriana/métodos , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción/métodos , beta-Lactamasas/metabolismo , Antibacterianos/farmacología , Bacterias/efectos de los fármacos , Bacterias/enzimología , Proteínas Bacterianas/genética , Farmacorresistencia Bacteriana , Pruebas de Sensibilidad Microbiana , Juego de Reactivos para Diagnóstico , beta-Lactamasas/genéticaRESUMEN
The emergence of daptomycin (DAP) resistant Enterococcus species has increased worldwide, but the mechanisms for DAP resistance are not fully understood. We report a case of DAP resistant Enterococcus faecalis, from a clinical sample of a patient with diabetic ulcers, after DAP therapy. Whole-genome sequencing analysis revealed that the isolate had a loss-of-function point mutation within liaX encoding DAP-sensing surface protein, which inhibits the LiaFSR systems and cell membrane remodeling. This is the first case report of a clinical DAP resistant E. faecalis with a mutation in liaX.
Asunto(s)
Daptomicina , Antibacterianos/farmacología , Antibacterianos/uso terapéutico , Proteínas Bacterianas/genética , Membrana Celular , Daptomicina/farmacología , Daptomicina/uso terapéutico , Farmacorresistencia Bacteriana/genética , Enterococcus faecalis/genética , Humanos , Proteínas de la Membrana , Pruebas de Sensibilidad Microbiana , Mutación/genéticaRESUMEN
Autoimmune thyroid diseases (AITDs), including Hashimoto's disease (HD) and Graves' disease (GD), are archetypes of organ-specific autoimmune diseases, but the prognosis of patients with AITD varies. Autoimmune diseases, including AITDs, are believed to develop in response to both genetic and environmental factors. Interleukin (IL)-6 plays a major role in B cell differentiation and T cell proliferation, and methylation of the IL6 gene is associated with IL-6 production. To clarify the role of IL6 gene methylation in the pathogenesis and prognosis of AITDs, we measured the methylation levels of -666, -664, -610, -491 and -426 CpG sites in the IL6 gene. We measured the methylation levels of 5 CpG sites in 29 patients with HD, 31 patients with GD and 16 healthy volunteers using pyrosequencing. The methylation level at each of the -664, -491 and -426 CpG sites was negatively correlated with the age at the time of sampling. Multiple regression analysis indicated that patients with HD, including severe or mild HD, showed higher methylation levels at the -426 CpG site than control subjects. Patients with intractable GD showed lower methylation levels at the -664 and -666 CpG sites than patients with GD in remission. In conclusion, IL6 gene methylation levels were related to the susceptibility to HD and the intractability of GD.
Asunto(s)
Metilación de ADN , Predisposición Genética a la Enfermedad , Enfermedad de Graves/genética , Enfermedad de Hashimoto/genética , Interleucina-6/genética , Adulto , Anciano , Alelos , Antitiroideos/uso terapéutico , Autoanticuerpos/sangre , Estudios de Casos y Controles , Islas de CpG , Progresión de la Enfermedad , Femenino , Expresión Génica , Frecuencia de los Genes , Enfermedad de Graves/diagnóstico , Enfermedad de Graves/tratamiento farmacológico , Enfermedad de Graves/inmunología , Enfermedad de Hashimoto/diagnóstico , Enfermedad de Hashimoto/tratamiento farmacológico , Enfermedad de Hashimoto/inmunología , Humanos , Interleucina-6/sangre , Interleucina-6/inmunología , Masculino , Metimazol/uso terapéutico , Persona de Mediana Edad , Pronóstico , Regiones Promotoras Genéticas , Índice de Severidad de la Enfermedad , Tirotropina/sangre , Tirotropina/inmunología , Tiroxina/sangre , Tiroxina/inmunología , Tiroxina/uso terapéutico , Triyodotironina/sangre , Triyodotironina/inmunologíaRESUMEN
The intractability of Graves' disease (GD) and the severity of Hashimoto's disease (HD) vary among patients. Both genetic and environmental factors may be associated with their prognoses. To clarify the role of methylation of the IFNG gene in the pathogenesis and prognosis of (AITDs), we examined interferon gamma (IFNG) methylation levels at various CpG sites and genotyped IFNG +874 A/T and +2109 C/T polymorphisms. We analyzed methylation 59 patients with HD, 57 patients with GD and 26 healthy volunteers by pyrosequencing. We genotyped IFNG gene polymorphisms from 207 patients with GD, 208 patients with HD, and 102 healthy controls. The methylation levels of IFNG -54 CpG were higher in patients with intractable GD than in those with GD in remission, but there was no difference between patients with severe and mild HD. In carriers of IFNG +2109â¯T (CTâ¯+â¯TT) (85.5% in controls), the -54 CpG methylation levels were significantly higher in patients with intractable GD than in those with GD in remission. On the other hand, in carriers of IFNG +2109 CC, the -4293 CpG methylation levels were higher in intractable GD patients. The methylation levels of IFNG -54 CpG and -4293 CpG were negatively correlated with the age in HD, especially severe HD, patients and GD patients, respectively. There was no circadian variation but considerable daily variation in the methylation levels of IFNG -54 CpG. In conclusion, both the methylation levels of CpG sites and the functional polymorphisms in the IFNG gene were associated with the pathogenesis and prognosis of AITD, especially with GD intractability.