Antibiotic use, resistance rates low after a decade of stewardship efforts in SG

Ten years since the implementation of antimicrobial stewardship programmes (ASP) in Singapore, the use of several types of antibiotics has dropped, followed by reductions in antimicrobial resistance across several classes, as reported in a study.

ASP, which was rolled out in 2011 in all public hospitals and received SGD 20 million in funds, promotes the appropriate use of antimicrobials, including antibiotics. Each hospital developed and disseminated antibiotic guidelines for the empiric treatment of common infections and surgical antibiotic prophylaxis.

Data from five hospitals showed that the rate of broad-spectrum antibiotic use plunged by 4 percent between 2011 and 2018 and by a further 0.5 percent between 2018 to 2020. [Antimicrob Resist Infect Control 2023;12:82]

Overall broad-spectrum antibiotic use across the five acute care hospitals fell from 714.6 defined daily doses (DDDs) per 1,000 inpatient-days in Q1 of 2011 to 509.6 DDDs per 1,000 inpatient-days in Q4 of 2020, with an average quarterly percentage change of –0.8 percent (95 percent confidence interval [CI], –1.3 to –0.4). In 2011, ciprofloxacin was the most used drug, followed by ceftriaxone, piperacillin-tazobactam, amoxicillin-clavulanate, and levofloxacin. Ciprofloxacin remained the most frequently used drug in 2020, with levofloxacin surpassing the others in second place.

Likewise, the rates of use of antipseudomonal antibiotics (cefepime, ceftazidime, ciprofloxacin, colistin, doripenem, imipenem, meropenem, levofloxacin, piperacillin-tazobactam and polymyxin B) decreased significantly between Q4 of 2012 and Q4 of 2013 through Q4 of 2020. The reductions seen in third-generation cephalosporins, carbapenems, and quinolones were primarily driven by ceftriaxone, imipenem, and ciprofloxacin, respectively.

Meanwhile, the rates of use of beta-lactam/beta-lactamase inhibitors increased substantially between Q1 of 2011 and Q2 of 2014 and between Q4 of 2016 and Q3 of 2018.

Antibiotic resistance

Along with the said decline in antimicrobial use in acute care hospitals, the incidence density of antibiotic-resistant organisms dropped by 2.7 percent between 2012 and 2014 and by a further 1.0 percent between 2014 and 2020. This decrease remained significant even after excluding methicillin-resistant S aureus (MRSA).

A closer examination of the data showed a decline in the incidence density of ceftriaxone-resistant E coli and K pneumoniae, imipenem- or meropenem-resistant P aeruginosa and A baumannii, and MRSA and C difficile. On the other hand, imipenem or meropenem-resistant E coli and K pneumoniae increased significantly.

Encouraging 10 years

The “findings from the five-hospital analysis suggested that with systematic implementation of nationally funded resource-intensive ASP activities based on evidence and local antibiograms, broad-spectrum antibiotic utilization rate declined during the study period,” the investigators said. [Lancet Reg Health-Western Pac 2021;7:100084; Singap Med J 2019;60:387-396; Ann Acad Med Singap 2012;41:29-34; https://tablebuilder.singstat.gov.sg/table/TS/M870301]

They also acknowledged the rise in piperacillin-tazobactam use in hospitals. This was despite the provision of prospective review and feedback on carbapenem and piperacillin-tazobactam prescriptions and the high acceptance rate of ASP interventions.

“However, the increase could have been more substantial without ASP. The increase in [the use] of levofloxacin during the study period could be attributed to its increased use in the national tuberculosis treatment unit of one hospital,” according to the investigators.

“The work to ensure judicious use of antibiotics at our local hospitals where there is high antibiotic resistance is ongoing. The first decade of ASP work in Singapore is encouraging, but it is not always the case from overseas experience. Reports on reduction in ASP activities due to the COVID-19 pandemic highlights the importance of sustaining ASP to reduce the overuse of antibiotics and antibiotic resistance in the long run,” they said. [J Antimicrob Chemother 2020;75:1087-1090; Antibiot 2021;10:110; Antimicrob Resist Infect Control 2021;10:28]