Implementation of an antimicrobial stewardship programme and reduction in carbapenemase-producing Enterobacterales in an Australian local health district

Targeted 'knock out' therapy with a combination antimicrobial regimen restores treatment options in the management of extensively drug-resistant carbapenemase-producing organisms

Introduction. Cefiderocol (FDC) and the combination of ceftazidime-avibactam and aztreonam (CZA+ATM) are emerging therapeutic options to combat carbapenemase-producing organisms (CPOs) that exhibit resistance due to multiple β-lactamases.Hypothesis/Gap Statement. Molecular diagnostics and specialized antimicrobial susceptibility testing (AST) are infrequently available in most clinical laboratories, and outputs from reference laboratories are not always timely. Practical methods must be explored to provide meaningful advice to treat infections due to CPOs in real time.Aim. To evaluate the in vitro efficacy of FDC and CZA+ATM against CPOs and to compare colistin (CST) MICs obtained locally with those from the reference laboratory.Methodology. CPOs isolated from 2017 to 2023 inclusive were retrieved. AST for FDC was performed using disc diffusion, CZA and ATM individually by E-tests and the E-test superposition method for the combination CZA+ATM. CST AST was performed locally using the VITEK2 system, and MICs were compared with those attained from the reference laboratory where manual broth microdilution is performed.Results. Fifty-eight CPOs were analysed. OXA-48 was the most frequently detected carbapenemase (37.9%, n=22). Co-existing β-lactamases of Ambler classes A and C were present for 79.3% of CPOs (n=46). Twenty-nine isolates (50%) were found to be susceptible to FDC. Fifty-seven isolates (98.3%) were susceptible to CST according to the VITEK2, compared to 44 of 47 tested isolates (93.6%) by the reference broth microdilution. Essential agreement was found to be 78.7%, and categorical agreement was 91.5% with one major error and three very major errors (VMEs) reported. CZA+ATM was tested against 26 CPOs, all of which harboured metallo-β-lactamases. Synergy was detected for all except one isolate where additivity was noted. Of the 32 isolates where combination therapy was not assessed, 29 (90.6%) possessed serine-β-lactamases and were susceptible to CZA monotherapy, whilst three (9.4%) possessed an isolated metallo-β-lactamase and were susceptible to ATM monotherapy.Conclusions. FDC appears to perform favourably against CPOs harbouring serine-β-lactamases, but not metallo-β-lactamases. The VITEK2 may provide presumptive categorical information for CST susceptibility, but MICs must be confirmed by broth microdilution as VMEs can lead to treatment failures. Moreover, our study confirms potent in vitro activity of CZA+ATM against CPOs expressing multiple β-lactamases.

Antimicrobial Use and Carbapenem-Resistant Enterobacterales in Korea: A Nationwide Case-Control Study With Propensity Score Matching

BACKGROUND

Nationwide research on the association between carbapenem-resistant Enterobacterales (CREs) and antibiotic use is limited.

METHODS

This nested case-control study analyzed Korean National Health Insurance claims data from April 2017 to April 2019. Based on the occurrence of CRE, hospitalized patients aged ≥ 18 years were classified into CRE (cases) and control groups. Propensity scores based on age, sex, modified Charlson comorbidity score, insurance type, long-term care facility, intensive care unit stay, and acquisition of vancomycin-resistant Enterococci were used to match the case and control groups (1:3).

RESULTS

After matching, the study included 6,476 participants (1,619 cases and 4,857 controls). Multivariable logistic regression analysis revealed that the utilization of broad-spectrum antibiotics, such as piperacillin/tazobactam (adjusted odds ratio [aOR], 2.178; 95% confidence interval [CI], 1.829-2.594), third/fourth generation cephalosporins (aOR, 1.764; 95% CI, 1.514-2.056), and carbapenems (aOR, 1.775; 95% CI, 1.454-2.165), as well as the presence of comorbidities (diabetes [aOR, 1.237; 95% CI, 1.061-1.443], hemiplegia or paraplegia [aOR, 1.370; 95% CI, 1.119-1.679], kidney disease [aOR, 1.312; 95% CI, 1.105-1.559], and liver disease [aOR, 1.431; 95% CI, 1.073-1.908]), were significantly associated with the development of CRE. Additionally, the CRE group had higher mortality (8.33 vs. 3.32 incidence rate per 100 person-months, P < 0.001) and a total cost of healthcare utilization per person-month (15,325,491 ± 23,587,378 vs. 5,263,373 ± 14,070,118 KRW, P < 0.001) than the control group.

CONCLUSION

The utilization of broad-spectrum antibiotics and the presence of comorbidities are associated with increasing development of CRE. This study emphasizes the importance of antimicrobial stewardship in reducing broad-spectrum antibiotic use and CRE disease burden in Korea.

Multi-year antimicrobial-resistance trends in urine Escherichia coli isolates from both community-based and hospital-based laboratories of an Australian local health district

OBJECTIVES

Efforts to monitor and combat antimicrobial resistance (AMR) are typically focused on the hospital-based laboratory setting. The aim of this study was to longitudinally examine and compare trends in AMR among urine Escherichia coli isolates from a private community-based laboratory and a public hospital-based laboratory in an Australian local health district.

METHODS

A total of 108 262 urine E. coli isolates from a public hospital-based laboratory (N = 34 103) and a private community-based laboratory (N = 74 159) in a single health district between 2007-2019 were analysed. Linear regression was used to identify significance of change in AMR rates in both laboratories independently and detect any significant interaction of each setting in proportional change over the study period.

RESULTS

Similar AMR trends were detected among urinary E. coli isolates in private community-based laboratory and public hospital-based laboratory settings over 12 y. AMR rates were consistently higher in the public hospital-based setting. Ampicillin was the only antibiotic for which the E. coli resistance trend did not significantly change over the time period in either laboratory setting. All other antibiotics showed a significant increase in AMR rates over time in both settings.

CONCLUSIONS

AMR rates in both the private community-based laboratory and public hospital-based laboratory settings increased over time and were consistently higher in the public hospital-based laboratory setting. Since private laboratories handle the vast majority of pathology volumes in community outpatient settings in Australia, interventions incorporating the community-based laboratory setting are critical to addressing AMR in the community.

Key predictors and burden of meticillin-resistant Staphylococcus aureus in comparison with meticillin-susceptible S. aureus infections in an Australian hospital setting

BACKGROUND

Staphylococcus aureus is associated with significant mortality and increased burden on the healthcare system. Relatively few reliable estimates are available regarding the impact of meticillin-resistant Staphylococcus aureus (MRSA) compared to meticillin-susceptible Staphylococcus aureus (MSSA) infections.

AIM

To compare patients with MRSA and MSSA infection to identify differences in inpatient mortality, length of stay and cost of hospital services, and identify predictors of MRSA as a cause of Staphylococcus aureus infection.

METHODS

An analytical, retrospective, longitudinal study using non-identifiable linked data on adults admitted to hospitals of a health district in Australia with a diagnosis of Staphylococcus aureus infection over a 10-year period. The main outcome measure was 30-day inpatient mortality. Secondary endpoints included total overnight stays, all-cause inpatient mortality, and hospitalisation cost within 1 year of index admission.

FINDINGS

Inpatient mortality at 30, 100, and 365 days was estimated to be significantly greater for patients with MRSA infections. The mean additional cost of MRSA infections when controlling for additional factors was $5,988 and 4 nights' additional hospital stay per patient within 1 year of index admission. Key predictors of MRSA infection were: date of index admission, higher comorbidity score, greater socio-economic disadvantage, admission to hospital other than via the emergency department, older age, and prior admission to hospital within 28-days of index admission.

CONCLUSIONS

MRSA infections are associated with increased inpatient mortality, cost and hospital length of stay, compared to those caused by MSSA. Efforts are required to alleviate the additional burden of MRSA infections on patients and healthcare systems.

Antimicrobial stewardship in Australia: the role of qualitative research in programme development

Antimicrobial stewardship (AMS) in Australia is supported by a number of factors, including enabling national policies, sectoral clinical governance frameworks and surveillance programmes, clinician-led educational initiatives and health services research. A One Health research programme undertaken by the National Centre for Antimicrobial Stewardship (NCAS) in Australia has combined antimicrobial prescribing surveillance with qualitative research focused on developing antimicrobial use-related situational analyses and scoping AMS implementation options across healthcare settings, including metropolitan hospitals, regional and rural hospitals, aged care homes, general practice clinics and companion animal and agricultural veterinary practices. Qualitative research involving clinicians across these diverse settings in Australia has contributed to improved understanding of contextual factors that influence antimicrobial prescribing, and barriers and facilitators of AMS implementation. This body of research has been underpinned by a commitment to supplementing 'big data' on antimicrobial prescribing practices, where available, with knowledge of the sociocultural, technical, environmental and other factors that shape prescribing behaviours. NCAS provided a unique opportunity for exchange and cross-pollination across the human and animal health programme domains. It has facilitated synergistic approaches to AMS research and education, and implementation of resources and stewardship activities. The NCAS programme aimed to synergistically combine quantitative and qualitative approaches to AMS research. In this article, we describe the qualitative findings of the first 5 years.

The effectiveness of Check of Medication Appropriateness for antimicrobial stewardship: an interrupted time series analysis

OBJECTIVES

Inappropriate prescribing of antimicrobials in hospitals contributes to the emergence of resistance and adverse drug events. To support antimicrobial stewardship (AMS), clinical decision rules focusing on antimicrobial therapy were implemented in the 'Check of Medication Appropriateness' (CMA). The CMA is a hospital-wide pharmacist-led medication review service consisting of a clinical rule-based screening for potentially inappropriate prescriptions (PIPs). We aimed to investigate the impact of the CMA on antimicrobial prescribing.

METHODS

An interrupted time series study was performed at the University Hospitals Leuven. The pre-implementation cohort was exposed to standard-of-care AMS. Afterwards, an AMS-focused CMA comprising 41 specific clinical rules, targeting six AMS objectives, was implemented in the post-implementation period. A regression model was used to assess the impact of the intervention on the number of AMS-related residual PIPs between both periods. The total number of recommendations and acceptance rate was recorded for the 2 year post-implementation period.

RESULTS

Pre-implementation, a median proportion of 75% (range: 33%-100%) residual PIPs per day was observed. After the CMA intervention, the proportion was reduced to 8% (range: 0%-33%) per day. Use of clinical rules resulted in an immediate relative reduction of 86.70% (P < 0.0001) in AMS-related residual PIPs. No significant underlying time trends were observed during the study period. Post-implementation, 2790 recommendations were provided of which 81.32% were accepted.

CONCLUSIONS

We proved that the CMA approach reduced the number of AMS-related residual PIPs in a highly significant and sustained manner, with the potential to further expand the service to other AMS objectives.

Antimicrobial Stewardship Programs in Northwest China: A Cross-Sectional Survey of Perceptions, Involvement, and Perceived Barriers Among Hospital Pharmacists

Background: Antimicrobial stewardship (AMS) is a key prevention strategy in addressing the global concern of increasing antimicrobial resistance (AMR). Pharmacists are one of the integral members of AMS hospital teams around the world. Toward reducing AMR, a major strategy in China is to improve the capacity and participation of pharmacists in the AMS framework. However, little is known about how hospital pharmacists perceive their position and participation in AMS work, and the barriers to this work in China, especially in the Northwest region. Methods: Region this work describes a cross-sectional, anonymous, online survey study. Hospital pharmacists from five provinces/autonomous regions in northwest China were invited to participate in June and July 2020. Participants completed the survey by using WeChat, a popular social application in China. We purposefully distributed the questionnaire link and QR code to hospital pharmacists through the hospital antimicrobial resistance surveillance network, hospital antimicrobial consumption surveillance network, provincial and city pharmaceutical associations, and hospital pharmacist WeChat groups. Results: Out of 1032 respondents, 93.1% believed that AMS programs promote the judicial prescribing of antimicrobials, 95.5% strongly agreed that AMS could reduce the widespread use of antimicrobials, and 92.3% believed that AMS could improve medical services. Pharmacists were most likely to be involved in AMS through reviewing prescriptions of antimicrobials, intervening in inappropriate prescriptions, and providing feedback on antimicrobial prescriptions and medical orders. Barriers to participating in AMS included workload (59.5% of respondents), ineffective communication between pharmacists and doctors (57.7%), and inadequate knowledge of AMS (47.0%). Differences in responses were found between the five surveyed provinces. A significant association was found between median involvement scores and gender, age, education, level of superiority, experience, and type of hospital (p < 0.05). Conclusion: Pharmacists perceived that AMS programs are important, but that their involvement in related activities is limited in all provinces. Further studies and strategies should consider how to overcome the identified barriers to optimize the participation of pharmacists in AMS programs.