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Five thousand actinomycetes were isolated from soil samples collected from rainforests in Singapore and the generic identities of these isolates were determined by using a procedure that combined morphological, chemotaxonomic and 16S rDNA sequence-based phylogenetic analyses. Actinomycetes belonging to a total of 36 genera were identified. The most abundant isolates are members of Streptomyces, Micromonospora, Actinoplanes, Actinomadura, Nonomuria, Nocardia and Streptosporangium. By phylogenetic analysis of 16S rDNA sequences of our isolates together with those of known actinomycete species, we also evaluated the species diversity of several genera including Streptomyces, Micromonospora, Nonomuria, and Actinomadura. We found that: first, the tropical isolates are present in most clades represented by known species; and second, many tropical isolates form new clades distant from the known species, indicating the presence of unidentified taxa at both species and genus levels. Based on these results, we conclude that actinomycete diversity in the tropical rainforest is very great and should represent an excellent source for discovery of novel bioactive compounds. [ABSTRACT FROM AUTHOR]

Singapore has a relative higher prevalence of Hepatitis B carriage at 3.6%. The risk of Hepatitis B virus (HBV) flare which is increased in patients receiving anthracycline chemotherapy has clinical relevance due to associated morbidity. Guidelines recommend a risk-adaptive screening strategy. This study aims to analyze the practice of HBV screening, and incidence of flare among non-metastatic breast cancer patients treated with anthracyclines. This is a retrospective review of all non-metastatic breast cancer in the Joint Breast Cancer Registry (JBCR) treated with (neo)adjuvant doxorubicin based therapy between August 2015 and December 2016, across 3 tertiary institutions in Singapore. We examined data collected prior to chemotherapy initiation regarding HBV status, including liver function (LFT), HBV surface antigen (HBsAg), antibody to HBV (Anti HBs), HBV core total antibody (Anti HBc) and HBV deoxyribonucleic levels (HBV DNA). We reviewed the course of HBV carriers (HBsAg positive) or prior HBV exposed patients (Anti HBc total positive and HBsAg negative) during chemotherapy for any HBV flare (abrupt rise of alanine aminotransferase levels to more than 5 times upper limit of normal in a carrier). 492 early breast cancer patients were examined. 484 (98.3%) had HBsAg, 159 (32.3%) had Anti HBs and 16 (3.3%) had Anti HBc performed prior to starting chemotherapy. There were 12 HBV carriers and 4 with previous HBV exposure. Among the 12 HBV carriers, 4 were on antivirals prior to the diagnosis of breast cancer, and 8 were started on antivirals following diagnosis. 1 patient received doxorubicin prior to starting antivirals and developed HBV flare after the first cycle. The patient was started on entecavir, with improvement in HBV DNA levels and LFT, and chemotherapy was resumed. Remaining carriers did not develop flares. The patients with prior HBV exposure were monitored with serial LFT, and did not develop transaminitis. Patients are almost universally screened for HBV with HBsAg prior to anthracyclines. Our data was consistent with local carriage rate. The incidence of flare is low with appropriate antiviral prophylaxis. HBsAg alone may be sufficient for screening. The authors. Has not received any funding. All authors have declared no conflicts of interest. [ABSTRACT FROM AUTHOR]