A Qualitative Study on the Implementation of the National Action Plan on Antimicrobial Resistance in Singapore.

Antimicrobial resistance (AMR) is a global public health threat that affects humans, animals, and the environment across the One Health spectrum. Singapore launched its own National Strategic Action Plan (NSAP) on AMR in 2017 with the aim of tackling the growing threat of AMR in Singapore through coordinated approaches. However, little is known about the implementation of the NSAP. In this study, we analysed the implementation of the NSAP with guidance from an AMR governance framework. We conducted in-depth interviews with 20 participants across the One Health spectrum. The interviews were transcribed verbatim and analysed thematically. Overall, the implementation of activities against AMR was more advanced with respect to human health compared to other sectors such as (1) AMR and antimicrobial use (AMU) surveillance systems in hospitals; (2) the hospital antimicrobial stewardship (AMS) service and legislation to optimise AMU; (3) the national children and adults vaccination programme for IPC; (4) multiple avenues for education and awareness for both professionals and public; and (5) extensive research and collaboration networks with many sources of funding. Areas that were lacking presented problems including (1) an incomplete surveillance system for AMR and AMU across all sectors; (2) the need for better AMS and legislation in some sectors; (3) insufficient innovation in education for sustained behavioural modification; and (4) the need for more open research collaborations and the translation of research into policy outcomes. Improvements in these areas will enhance the overall implementation of the NSAP through a more holistic One Health approach.

A Qualitative Study on the Policy Process and Development of the National Action Plan on Antimicrobial Resistance in Singapore.

The global public health threat of antimicrobial resistance (AMR) has been accelerated by many interrelated factors spanning across One Health-human health, animal health, and the environment. Singapore launched its own National Strategic Action Plan (NSAP) on AMR in November 2017 with the aim of tackling the growing threat of AMR in Singapore through coordinated approaches. However, little is known about the policy process and development of the NSAP in Singapore. In this study, we analysed these aspects using an AMR governance framework. In-depth interviews were conducted with 20 participants across the One Health spectrum. The interviews were transcribed verbatim and analysed thematically. Areas that were well executed included (1) good coordination across various agencies, (2) a dedicated office to coordinate the work on the NSAP, and (3) a high level of governmental support. Areas that were lacking included (1) a lack of participation from certain sectors, (2) insufficient awareness around the AMR issue, (3) constraints in information sharing, and (4) a lack of ideal indicators to track the progress in addressing AMR. Improvements in these areas will provide a more holistic One Health engagement in support of the effective planning and implementation of the NSAP.

Degradable antimicrobial polycarbonates with unexpected activity and selectivity for treating multidrug-resistant Klebsiella pneumoniae lung infection in mice.

Multidrug resistant (MDR) Klebsiella pneumoniae is a major cause of healthcare-associated infections around the world, with attendant high rates of morbidity and mortality. Progressive reduction in potency of antibiotics capable of treating MDR K. pneumoniae infections - including lung infection - as a consequence of escalating drug resistance provides the motivation to develop drug candidates targeting MDR K. pneumoniae. We recently reported degradable broad-spectrum antimicrobial guanidinium-functionalized polycarbonates with unique antimicrobial mechanism - membrane translocation followed by precipitation of cytosolic materials. These polymers exhibited high potency against bacteria with negligible toxicity. The polymer with ethyl spacer between the quanidinium group and the polymer backbone (pEt_20) showed excellent in vivo efficacy for treating MDR K. pneumoniae-caused peritonitis in mice. In this study, the structures of the polymers were optimized for the treatment of MDR Klebsiella pneumoniae lung infection. Specifically, in vitro antimicrobial activity and selectivity of guanidinium-functionalized polycarbonates containing the same number of guanidinium groups but of a shorter chain length and a structural analogue containing a thiouronium moiety as the pendent cationic group were evaluated. The polymers with optimal compositions and varying hydrophobicity were assessed against 25 clinically isolated K. pneumonia strains for antimicrobial activity and killing kinetics. The results showed that the polymers killed the bacteria more efficiently than clinically used antibiotics, and repeated use of the polymers did not cause drug resistance in K. pneumonia. Particularly, the polymer with butyl spacer (pBut_20) self-assembled into micelles at high concentrations, where the hydrophobic component was shielded in the micellar core, preventing interacting with mammalian cells. A subtle change in the hydrophobicity increased the antimicrobial activity while reducing in vivo toxicity. The in vivo efficacy studies showed that pBut_20 alleviated K. pneumonia lung infection without inducing damage to major organs. Taken together, pBut_20 is promising for treating MDR Klebsiella pneumoniae lung infection in vivo. STATEMENT OF SIGNIFICANCE: Multidrug resistant (MDR) Klebsiella pneumoniae is a major cause of healthcare-associated infections, with attendant high rates of morbidity and mortality. The progressive reduction in antibiotics capable of treating MDR K. pneumoniae infections - including lung infection - as a consequence of escalating drug resistance rates provides the motivation to develop drug candidates. In this study, we report a degradable guanidinium-functionalized polycarbonate with unexpected antimicrobial activity and selectivity towards MDR Klebsiella pneumoniae. A subtle change in polymer hydrophobicity increases antimicrobial activity while reducing in vivo toxicity due to self-assembly at high concentrations. The polymer with optimal composition alleviates Klebsiella pneumonia lung infection without inducing damage to major organs. The polymer is promising for treating MDR Klebsiella pneumoniae lung infection in vivo.

Surveillance and correlation of antibiotic prescription and resistance of Gram-negative bacteria in Singaporean hospitals.

A surveillance study was performed in four Singapore public hospitals from 2006 to 2008 to determine the correlation between antibiotic prescription and Gram-negative bacterial antimicrobial resistance. Targeted organisms included ceftriaxone- and ciprofloxacin-resistant Escherichia coli and Klebsiella pneumoniae, as well as imipenem-resistant Pseudomonas aeruginosa and Acinetobacter spp. Antibiotic prescription data were collated in the WHO anatomical therapeutic chemical (ATC)/defined daily dose (DDD) format, while antibiotic resistance was expressed as incidence density adjusted for total inpatient-days every quarter. Individual trends were determined by linear regression, while possible associations between antibiotic prescription and resistance were evaluated via cross-correlation analysis. Results over 3 years indicated significantly rising incidence densities of ceftriaxone- and ciprofloxacin-resistant E. coli and imipenem-resistant Acinetobacter spp. (blood isolates only). Antimicrobial-resistant Klebsiella pneumoniae rates declined. The prescription rates of piperacillin-tazobactam, ertapenem, meropenem, ciprofloxacin, and levofloxacin increased significantly, while imipenem and moxifloxacin prescription decreased. Cross-correlation analysis demonstrated possible associations between prescription of fluoroquinolones and ciprofloxacin-resistant E. coli (R(2) = 0.46), fluoroquinolones and ceftriaxone-resistant E. coli (R(2) = 0.47), and carbapenems and imipenem-resistant Acinetobacter spp. (R(2) = 0.48), all at zero time lag. Changes in meropenem prescription were associated with a similar trend in imipenem-resistant Acinetobacter blood isolates after a 3-month time lag. No correlation was found between cephalosporin use and resistance. In conclusion, our data demonstrated correlation between prescription of and Gram-negative bacterial resistance to several, but not all, key antimicrobial agents in Singapore hospitals. In areas where Gram-negative bacterial resistance is endemic and prescription of broad-spectrum antimicrobial agents is high, factors other than antimicrobial usage may be equally important in maintaining high resistance rates.