RESUMEN
Two bacterial strains, HKU50T and HKU46, were isolated in Hong Kong from the blood culture and the peritoneal dialysis effluent of two patients. The strains are Gram-stain-positive, acid-fast, non-motile, non-sporulating bacilli. They grow on Columbia agar with 5 % defibrinated sheep blood and brain-heart infusion agar under aerobic conditions with 5 % CO2 at 37 °C as pink-to-orange, non-haemolytic colonies. The strains are catalase-positive and oxidase-negative, and have a unique biochemical profile distinguishable from other closely related species. DNA sequencing revealed that both isolates possessed multiple intra-genomic 16S rRNA gene copies (99.8-100 % sequence identities to Gordonia lacunae NRRL B-24551T and Gordonia terrae NRRL B-16283T). Phylogenetic analysis of the 16S rRNA gene, secA1 and gyrB showed that the two isolates formed a distinct branch within the genus Gordonia and were most closely related to G. lacunae and G. terrae. DNA-DNA hybridization demonstrated ≤53.7 % and ≤49.4 % DNA relatedness between the two isolates and G. lacunae, and between the two isolates and G. terrae, respectively. Hierarchical cluster analysis of MALDI-TOF MS main spectrum profiles showed that strains HKU50T and HKU46 were closely related to each other, but were distinct from G. lacunae, G. terrae, or any other species of the genus Gordonia in the Bruker database. The chemotaxonomic traits of the two strains were highly similar, and the major fatty acids were summed feature 4 (iso-C15 : 0 2-OH/C16 : 1trans-9), C16 : 0, C18 : 1cis-9, and tuberculostearic acid. A novel species named Gordonia hongkongensis sp. nov. is proposed to accommodate strains HKU50T and HKU46, with strain HKU50T (=CCOS 955T=CIP 111027T=NBRC 111234T=NCCP 16210T) as the type strain.
Asunto(s)
Cultivo de Sangre , Bacteria Gordonia/clasificación , Diálisis Peritoneal , Filogenia , Técnicas de Tipificación Bacteriana , Análisis por Conglomerados , ADN Bacteriano/genética , Ácidos Grasos/química , Genes Bacterianos , Bacteria Gordonia/genética , Bacteria Gordonia/aislamiento & purificación , Hong Kong , Humanos , Lactante , Masculino , Persona de Mediana Edad , Hibridación de Ácido Nucleico , Pigmentación , ARN Ribosómico 16S/genética , Análisis de Secuencia de ADNRESUMEN
BACKGROUND: Long-term outcomes in non-HIV immunocompromised patients with disseminated Mycobacterium avium complex (dMAC) infections are unknown and the need for post-treatment secondary prophylaxis against MAC is uncertain in this setting. The objective of this study was to determine the need of continuing secondary anti-MAC prophylaxis in non-HIV patients after completing treatment of the primary dMAC episode. METHODS: We conducted a ten-year multi-center analysis of non-HIV immunosuppressed patients with dMAC infections in Hong Kong. RESULTS: We observed sixteen patients with dMAC during the study period of which five (31 %) were non-HIV immunosuppressed patients. In the non-HIV immunosuppressed group, three patients completed a treatment course without secondary prophylaxis, one patient received azithromycin-based secondary prophylaxis and one patient was still receiving therapy for the first dMAC episode. All the three patients who completed treatment without being given secondary prophylaxis developed recurrent dMAC infection requiring retreatment. CONCLUSIONS: In view of the high rate of dMAC infection recurrence in non-HIV immunocompromised patients following treatment completion, our data support long-term anti-MAC suppression therapy after treatment of the first dMAC infection episode in immunocompromised non-HIV patients, as is recommended for patients with advanced HIV. Tests of cell mediated immune function need to be evaluated to guide prophylaxis discontinuation in non-HIV patients.
Asunto(s)
Antibacterianos/uso terapéutico , Profilaxis Antibiótica , Azitromicina/uso terapéutico , Huésped Inmunocomprometido , Complejo Mycobacterium avium , Infección por Mycobacterium avium-intracellulare/tratamiento farmacológico , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Infecciones por VIH , Hong Kong , Humanos , Masculino , Infección por Mycobacterium avium-intracellulare/prevención & control , RecurrenciaRESUMEN
We report here four cases of continuous ambulatory peritoneal dialysis-related peritonitis caused by three different species of Gordonia. The portal of entry was likely through Tenckhoff catheters. 16S rRNA and secA1 gene sequencing are so far the most reliable methods for the accurate identification of Gordonia species.
Asunto(s)
Infecciones por Actinomycetales/diagnóstico , Adenosina Trifosfatasas/genética , Proteínas Bacterianas/genética , Bacteria Gordonia/aislamiento & purificación , Proteínas de Transporte de Membrana/genética , Técnicas de Diagnóstico Molecular/métodos , Peritonitis/diagnóstico , ARN Ribosómico 16S/genética , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción/métodos , Infecciones por Actinomycetales/microbiología , Anciano , Análisis por Conglomerados , Femenino , Bacteria Gordonia/química , Bacteria Gordonia/genética , Humanos , Masculino , Persona de Mediana Edad , Datos de Secuencia Molecular , Diálisis Peritoneal/efectos adversos , Peritonitis/microbiología , Filogenia , Canales de Translocación SEC , Proteína SecA , Análisis de Secuencia de ADN , Homología de SecuenciaRESUMEN
We report the first fatal case of Campylobacter rectus infection due to a subdural empyema and ruptured mycotic intracranial aneurysm and two cases of limb-threatening C. rectus necrotizing soft tissue and bone infection and empyema thoracis that responded to amoxicillin-clavulanate and surgical debridement and drainage. All three strains were identified by 16S rRNA sequencing.