Tsukamurella serpentis sp. nov., isolated from the oral cavity of Chinese cobras (Naja atra).

Two bacterial strains, HKU54T and HKU55, were isolated from the oral cavity of two Chinese cobras (Naja atra) in Hong Kong. 16S rRNA gene sequence analysis revealed 100 % sequence identity between HKU54T and HKU55, and the two strains shared 99.0 % sequence identities with Tsukamurella inchonensis ATCC 700082T. The two strains had unique biochemical profiles distinguishable from closely related species of the genus Tsukamurella. DNA-DNA hybridization confirmed that they belonged to the same species (≥92.1±7.9 % DNA-DNA relatedness) but were distinct from all other known species of the genus Tsukamurella (≤52.6±5.3 % DNA-DNA relatedness). Chemotaxonomic and morphological analyses of the two strains also demonstrated results consistent with their classification in the genus Tsukamurella. The DNA G+C contents of strains HKU54T and HKU55 were 69.2±1.5 mol% and 69.2±1.3 mol% (mean±sd; n=3) respectively. A novel species, Tsukamurella serpentis sp. nov., is proposed to accommodate strains HKU54T and HKU55, with HKU54T (=JCM 31017T=DSM 100915T) designated as the type strain.

High recurrence rate supports need for secondary prophylaxis in non-HIV patients with disseminated mycobacterium avium complex infection: a multi-center observational study.

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.