INTRODUCTIONHuman immunodeficiency virus type 1 (HIV-1) genotyping resistance test (GRT) is essential for monitoring HIV-1 drug resistance mutations (DRMs). High cost and HIV-1 genetic variability are challenges to assay availability in Singapore. An in-house Sanger sequencing-based GRT method was developed at the Communicable Disease Centre (CDC), Singapore's HIV national treatment reference centre for both subtype B and non-subtype B HIV-1.

MATERIALS AND METHODSThe in-house GRT sequenced the fi rst 99 codons of protease (PR) and 244 codons of reverse transcriptase (RT) in the pol gene. The results were compared with the Food and Drug Administration (FDA)-approved ViroSeq™ HIV-1 Genotyping System.

RESULTSSubtype assignment for the 46 samples were as follows: 31 (67.4%) CRF01_AE, 14 (30.5%) subtype B and 1 (2.1%) subtype C. All 46 samples had viral load of ≥500 copies/mL, and were successfully amplified by the in-house primer sets. Compared to the ViroSeq™ test, our in-house assay showed drug-resistance conferring codon concordance of 99.9% at PR and 98.9% at RT, and partial concordance of 0.1% at PR and 1.1% at RT. No discordant result was observed.

CONCLUSIONThe assay successfully identified DRMs in both subtype AE and B, making it suitable for the efficient treatment monitoring in genetically diverse population. At less than half of the running cost compared to the ViroSeq™ assay, the broadly sensitive in-house assay could serve as a useful addition to the currently limited HIV genotyping assay options for resource-limited settings, thereby enhancing the DRM surveillance and monitoring in the region.

Anti-Retroviral Agents ; pharmacology ; Drug Resistance, Viral ; genetics ; Genes, pol ; genetics ; Genotyping Techniques ; methods ; HIV Infections ; drug therapy ; virology ; HIV-1 ; drug effects ; genetics ; Humans ; Mutation ; Sequence Analysis, DNA ; methods ; Singapore

Objective:Escalator signage could be playing a vital role to alert users for safe use of escalators.This study aimed to evaluate the availability,standardization,and content of safety information on escalator signage in the shopping malls.Methods:An observational study was conducted from November 2017 to February 2018 to assess the availability,standardization of safety information among the signage inside the shopping mall,and the content of safety information for public safety in Malaysia.A checklist was developed by adapting escalator safety guidelines from seven countries and regions including Malaysia.Data collectors identified from the selected states were required to capture three photographs at different angles of the escalator signage for each ascending and descending directions at each entrance of the mall.Descriptive analysis was performed;each criterion was presented in frequency and percentage.Results:A total of 268 escalators from 84 shopping malls in 9 states of Malaysia were assessed.Two operating escalators were not equipped with signage.More than one-fifth (23.0％) of the signage was not standardized within the mall.The majority of safety information was displayed in the form of a pictogram,a minority of signage displayed information in both pictogram and text format:"children must hold hand" (12.7％) and "be careful of long clothing" (10.8％),respectively.Nevertheless,"toddlers should be carried" (8.6％) and "take extra care with rubber shoes/tied shoes/laces" (30.2％) were found absent in most of the signage.Conclusion:Escalator signage was present in almost all of the escalators observed.However,non-standardization of the signage of escalators should warrant the attention of relevant authorities to revise the safety guidelines and improve the quality of escalator.