Changing profile of Helicobacter pylori primary antibiotic resistance in Singapore over two decades

Antibiotic resistance is a key reason for Helicobacter pylori (H. pylori) treatment failure and updated local data are important to guide the choice of empiric first-line therapy. Clarithromycin-based triple therapy (TT) is currently the first-line treatment in Singapore. Our primary aim was to determine the change in pattern of primary antibiotic resistance of H. pylori in Singapore as well as TT success rate.

A registry of H. pylori isolates was tested for primary antibiotic resistance and were analyzed from year 2001 to 2020. Treatment outcome data based on ¹³C-urea breath test (¹³C-UBT) results of empiric first-line 2-week TT from 2019 to 2020 were also analyzed retrospectively.

A total of 387 H. pylori isolates were included. Rates of resistance to clarithromycin as well as tetracycline showed a downtrend in the last 5 years (clarithromycin: 2001-2002: 8.57%; 2007-2008: 14.14%; 2013-2014: 18.09%; 2019-2020: 13.71%; tetracycline: 2001-2002: 5.71%; 2007-2008: 7.07%; 2013-2014: 7.45%; 2019-2020: 0%). The resistance rate for amoxicillin remained low (2001-2002: 2.86%; 2007-2008: 5.05%; 2013-2014: 4.26%; 2019-2020: 7.26%). There was a steady increase in the rate of levofloxacin resistance (2001-2002: 5.71%; 2007-2008: 11.11%; 2013-2014: 15.96%; 2019-2020: 16.94%). From 2019 to 2020, the rate of successful TT was 91.67% (891/972).

The latest rate of clarithromycin resistance in 2019 to 2020 remained below the threshold of 15% and eradication rates remain high; thus, TT remains appropriate as an empiric first-line treatment in Singapore.