Estimating the burden of antimicrobial resistance: a systematic literature review

Antibacterial effects of low-temperature plasma generated by atmospheric-pressure plasma jet are mediated by reactive oxygen species

Emergence and spread of antibiotic resistance calls for development of non-chemical treatment options for bacterial infections. Plasma medicine applies low-temperature plasma (LTP) physics to address biomedical problems such as wound healing and tumor suppression. LTP has also been used for surface disinfection. However, there is still much to be learned regarding the effectiveness of LTP on bacteria in suspension in liquids, and especially on porous surfaces. We investigated the efficacy of LTP treatments against bacteria using an atmospheric-pressure plasma jet and show that LTP treatments have the ability to inhibit both gram-positive (S. aureus) and gram-negative (E. coli) bacteria on solid and porous surfaces. Additionally, both direct LTP treatment and plasma-activated media were effective against the bacteria suspended in liquid culture. Our data indicate that reactive oxygen species are the key mediators of the bactericidal effects of LTP and hydrogen peroxide is necessary but not sufficient for antibacterial effects. In addition, our data suggests that bacteria exposed to LTP do not develop resistance to further treatment with LTP. These findings suggest that this novel atmospheric-pressure plasma jet could be used as a potential alternative to antibiotic treatments in vivo.

Social science research contributions to antimicrobial resistance: protocol for a scoping review

BACKGROUND

Antimicrobial resistance (AMR) is an escalating global health issue with complex and dynamic interdependencies, high uncertainty and decision stakes, multiple drivers and stakeholders with diverse values and interests, and various aspects and outcomes. Addressing and combating this critical global challenge requires the formation and establishment of an interdisciplinary research approach that goes beyond the biosciences principally concerned with antimicrobial resistance to include other relevant natural and social sciences. The objective of this study will be to review and map existing social science knowledge and literature relating to antimicrobial resistance.

METHODS

The review team will undertake the scoping review using the Arksey and O'Malley methodological framework and also the Joanna Briggs Institute methods manual. Publications in English (from 1998 onwards) will be searched using several databases including PubMed/MEDLINE, Web of Science, Scopus, Anthropological Plus, Sociological Abstracts, International Bibliography of the Social Sciences (IBSS), PsycINFO and EconLit. Grey literature will also be searched (e.g. Google Scholar). Two reviewers will independently screen all citations, full-text articles, and abstract data. Publication types will include original articles, editorials, commentaries, protocols, and books in the social science research literature on AMR. All study designs (quantitative, qualitative, and mixed-methods) will be included. A PRISMA Flow Diagram of search and study selection will be used to report final figures on included and excluded studies. To provide a descriptive summary of the literature, data will be collated, stored, and charted using Microsoft Excel software. The analysis will also involve identifying themes and gaps in the existing literature and summarizing, describing and displaying all pertinent information using thematic construction approaches including qualitative content analysis methods.

DISCUSSION

This protocol describes a systematic method to identify, map, and synthesize social science research evidence on antimicrobial resistance. By mapping evidence and identifying potential knowledge gaps where further research is warranted, the resulting scoping review will provide useful insights for the design, implementation, and reorientation of future research agendas on AMR at multiple levels. Systematic review registration: This protocol has been registered with the Open Science Framework (OSF): https://osf.io/hyaem.

Prevalence of Potentially Pathogenic Antibiotic-Resistant Aeromonas spp. in Treated Urban Wastewater Effluents versus Recipient Riverine Populations: a 3-Year Comparative Study

Antibiotic resistance continues to be an emerging threat both in clinical and environmental settings. Among the many causes, the impact of postchlorinated human wastewater on antibiotic resistance has not been well studied. Our study compared antibiotic susceptibility among Aeromonas spp. in postchlorinated effluents to that of the recipient riverine populations for three consecutive years against 12 antibiotics. Aeromonas veronii and Aeromonas hydrophila predominated among both aquatic environments, although greater species diversity was evident in treated wastewater. Overall, treated wastewater contained a higher prevalence of nalidixic acid-, trimethoprim-sulfamethoxazole (SXT)-, and tetracycline-resistant isolates, as well as multidrug-resistant (MDR) isolates compared to upstream surface water. After selecting for tetracycline-resistant strains, 34.8% of wastewater isolates compared to 8.3% of surface water isolates were multidrug resistant, with nalidixic acid, streptomycin, and SXT being the most common. Among tetracycline-resistant isolates, efflux pump genes tetE and tetA were the most prevalent, though stronger resistance correlated with tetA. Over 50% of river and treated wastewater isolates exhibited cytotoxicity that was significantly correlated with serine protease activity, suggesting many MDR strains from effluent have the potential to be pathogenic. These findings highlight that conventionally treated wastewater remains a reservoir of resistant, potentially pathogenic bacterial populations being introduced into aquatic systems that could pose a threat to both the environment and public health.IMPORTANCE Aeromonads are Gram-negative, asporogenous rod-shaped bacteria that are autochthonous in fresh and brackish waters. Their pathogenic nature in poikilotherms and mammals, including humans, pose serious environmental and public health concerns especially with rising levels of antibiotic resistance. Wastewater treatment facilities serve as major reservoirs for the dissemination of antibiotic resistance genes (ARGs) and resistant bacterial populations and are, thus, a potential major contributor to resistant populations in aquatic ecosystems. However, few longitudinal studies exist analyzing resistance among human wastewater effluents and their recipient aquatic environments. In this study, considering their ubiquitous nature in aquatic environments, we used Aeromonas spp. as bacterial indicators of environmental antimicrobial resistance, comparing it to that in postchlorinated wastewater effluents over 3 years. Furthermore, we assessed the potential of these resistant populations to be pathogenic, thus elaborating on their potential public health threat.

Biofixation of atmospheric nitrogen in the context of world staple crop production: Policy perspectives

The extensive use of nitrogen (N) fertilizers implicates a paradox: while fertilizers ensure the supply of a large amount of food, they cause negative environmental externalities, including reduced biodiversity, and eutrophic streams and lakes. Moreover, such fertilizers may also result in a major public health hazard: increased antibiotic resistance. This article discusses the critical implications of perturbations in N cycle caused by excessive use of fertilizers and resulting policy implications as they relate to ecosystem services. While there are solutions such as cover crops, these solutions are expensive and inconvenient for farmers. We advocate the use of biological fixation (BF) for staple crops-microbiome mediated natural supply of fixed N. This would involve engineering a microbiome that can be grown cheaply and at industrial scale. Fertilizers resulting from such innovation are termed as "biofertilizers" in this article. Following a qualitative cost-benefit analysis broken down by key stakeholders and a quick exploration of policy frameworks as they relate to the advancement of biofertilizers, we propose a practical pathway of where and how research investments should be directed to make such a solution feasible. We make five policy recommendations for decision-makers to facilitate a successful trajectory for this solution: (1) Future agricultural science should seek to understand how BF might be employed as a practical and efficient strategy. This effort would require that industry and the government partner to establish a pre-competitive research laboratory equipped with the latest state-of-the-art technologies that conduct metagenomic experiments to reveal signature microbiomes and form novel symbiotic connections. (2) To have a smooth ride in the market, ag-bio companies should: (i) create awareness among farmers; (ii) impart skills to farmers in testing and using biofertilizers, and (iii) conduct extensive field tests and more research in studying the scalability potential of such fertilizers. (3)The United States Department of Agriculture (USDA) and state governments should provide research and development (R&D) tax credits to biotech companies specifically geared towards R&D investments aimed at increasing the viability of BF and microbiome engineering. (4) To control agricultural pollution in the biosphere, federal governments should consider passing a Clean Agriculture Act (CAA), including a specific clause that regulate the use of chemical fertilizers. (5) Governments and the UN Food and Agriculture Organization (FAO) should coordinate Biological Advanced Research in Agriculture (BARA)-a global agricultural innovation initiative for investments and research in biological fixation and ethical, legal, and social implications of such innovation. While biological fixation will be central in BARA, we envision it to conduct research around other agricultural innovations as well, such as increasing photosynthetic efficiency.

Antimicrobial stewardship programs; a two-part narrative review of step-wise design and issues of controversy Part I: step-wise design of an antimicrobial stewardship program

Regardless of one's opinion of antimicrobial stewardship programs (ASPs), it is hardly possible to work in hospital care and not be exposed to the term or its practical effects. Despite the term being relatively new, the number of publications in the field is vast, including several excellent reviews of general and specific aspects. Work in antimicrobial stewardship is complex, and includes not only aspects of infectious disease and microbiology, but also of epidemiology, genetics, behavioural psychology, systems science, economics and ethics, to name a few. This review aims to take several of these aspects and the scientific evidence of antimicrobial stewardship studies and merge them into two questions: How should we design ASPs based on what we know today? And which are the most essential unanswered questions regarding antimicrobial stewardship on a broader scale? This narrative review is written in two separate parts aiming to provide answers to the two questions. This first part is written as a step-wise approach to designing a stewardship intervention based on the pillars of unmet need, feasibility, scientific evidence and necessary core elements. It is written mainly as a guide to someone new to the field. It is sorted into five distinct steps: (a) focusing on designing aims; (b) assessing performance and local barriers to rational antimicrobial use; (c) deciding on intervention technique; (d) practical, tailored design including core element inclusion; and (e) evaluation and sustainability. The second part, published separately, formulates ten critical questions on controversies in the field of antimicrobial stewardship. It is aimed at clinicians and researchers with stewardship experience and strives to promote discussion, not to provide answers.

Systematic comparison of coexistence in models of drug-sensitive and drug-resistant pathogen strains

A number of mathematical models have recently been proposed to explain empirical trends of pathogen diversity. In particular, long-term coexistence of both drug-sensitive and drug-resistant variants of a single pathogen is something of a mystery, given that simple models of pathogens competing for the same ecological niche predict competitive exclusion, and more complex models admitting coexistence require assumptions that may not be justified. Coinfection is among the candidate mechanisms to generate coexistence, as it occurs in many pathogens and provides the opportunity for strains to interact directly. Recently, coinfection and competitive release have been described as creating a form of negative frequency-dependent selection that promotes coexistence, and a range of models containing coinfection have been proposed as having generic stable coexistence of multiple strains. This abundance of new models presents the challenge of comparison and interpretation. To this end, we describe a dimensionless quantity that can be used to compare the amount of coexistence generated by different models. We focus on models that include coinfection, although this framework could be generalized to a larger class of structured models.

Cost-effectiveness analysis comparing ceftazidime/avibactam (CAZ-AVI) as empirical treatment comparing to ceftolozane/tazobactam and to meropenem for complicated intra-abdominal infection (cIAI)

Background

The rising incidence of resistance to currently available antibiotics among pathogens, particularly Gram-negative pathogens, in complicated intra-abdominal infections (cIAIs) has become a challenge for clinicians. Ceftazidime/avibactam (CAZ-AVI) is a fixed-dose antibiotic approved in Europe and the United States for treating (in combination with metronidazole) cIAI in adult hospitalised patients who have limited or no alternative treatment options. The approval was based on the results of RECLAIM, a Phase III, parallel-group, comparative study (RECLAIM 1 [NCT01499290] and RECLAIM 2 [NCT01500239]). The objective of our study was to assess the cost-effectiveness of CAZ-AVI plus metronidazole compared with 1) ceftolozane/tazobactam plus metronidazole and 2) meropenem, as an empiric treatment for the management of cIAI in Italy.

Methods

A sequential, patient-level simulation model, with a 5-year time horizon and 3% annual discount rate (applied to both costs and health benefits), was developed using Microsoft Excel® to demonstrate the clinical course of the disease. The impact of resistant pathogens was included as an additional factor.

Results

In the base-case analysis, the CAZ-AVI sequence (CAZ-AVI plus metronidazole followed by a colistin + tigecycline + high-dose meropenem combination after treatment failure), when compared to sequences for ceftolozane/tazobactam (ceftolozane/tazobactam plus metronidazole followed by colistin + tigecycline + high-dose meropenem after treatment failure) and meropenem (meropenem followed by colistin + tigecycline + high-dose meropenem after treatment failure), had better clinical outcomes with higher cure rates (93.04% vs. 91.52%; 92.98% vs. 90.24%, respectively), shorter hospital stays (∆ = − 0.38 and ∆ = − 1.24 days per patient, respectively), and higher quality-adjusted life years (QALYs) gained per patient (4.021 vs. 3.982; 4.019 vs. 3.960, respectively). The incremental cost effectiveness ratio in the CAZ-AVI sequence was €4099 and €15,574 per QALY gained versus each comparator sequence, respectively, well below the willingness-to-pay threshold of €30,000 per QALY accepted in Italy.

Conclusions

The model results demonstrated that CAZ-AVI plus metronidazole could be a cost-effective alternative when compared with other antibiotic treatment options, as it is expected to provide better clinical benefits in hospitalised patients with cIAI in Italy.

Antimicrobial Resistance: Implications and Costs

Antimicrobial resistance (AMR) has developed as one of the major urgent threats to public health causing serious issues to successful prevention and treatment of persistent diseases. In spite of different actions taken in recent decades to tackle this issue, the trends of global AMR demonstrate no signs of slowing down. Misusing and overusing different antibacterial agents in the health care setting as well as in the agricultural industry are considered the major reasons behind the emergence of antimicrobial resistance. In addition, the spontaneous evolution, mutation of bacteria, and passing the resistant genes through horizontal gene transfer are significant contributors to antimicrobial resistance. Many studies have demonstrated the disastrous financial consequences of AMR including extremely high healthcare costs due to an increase in hospital admissions and drug usage. The literature review, which included articles published after the year 2012, was performed using Scopus, PubMed and Google Scholar with the utilization of keyword searches. Results indicated that the multifactorial threat of antimicrobial resistance has resulted in different complex issues affecting countries across the globe. These impacts found in the sources are categorized into three different levels: patient, healthcare, and economic. Although gaps in knowledge about AMR and areas for improvement are obvious, there is not any clearly understood progress to put an end to the persistent trends of antimicrobial resistance.

Antimicrobial Resistance in the Asia Pacific region: a meeting report

The Asia Pacific region, home to two-thirds of the world's population and ten of the least developed countries, is considered a regional hot-spot for the emergence and spread of antimicrobial resistance (AMR). Despite this, there is a dearth of high-quality regional data on the extent of AMR. Recognising the urgency to close this gap, Singapore organised a meeting to discuss the problems in the region and frame a call for action. Representatives from across the region and beyond attended the meeting on the "Antimicrobial Resistance in the Asia Pacific & its impact on Singapore" held in November 2018. This meeting report is a summary of the discussions on the challenges and progress in surveillance, drivers and levers of AMR emergence, and the promising innovations and technologies that could be used to combat the increasing threat of AMR in the region. Enhanced surveillance and research to provide improved evidence-based strategies and policies are needed. The major themes that emerged for an action plan are working towards a tailored solution for the region by harnessing the One Health approach, enhancing inter-country collaborations, and collaboratively leverage upon new emerging technologies. A regionally coordinated effort that is target-driven, sustainable and builds on a framework facilitating communication and governance will strengthen the fight against AMR in the Asia Pacific region.

Thymol tolerance in Escherichia coli induces morphological, metabolic and genetic changes

BACKGROUND

Thymol is a phenolic compound used for its wide spectrum antimicrobial activity. There is a limited understanding of the antimicrobial mechanisms underlying thymol activity. To investigate this, E. coli strain JM109 was exposed to thymol at sub-lethal concentrations and after 16 rounds of exposure, isolates with a 2-fold increased minimal inhibitory concentration (MIC) were recovered (JM109-Thyr). The phenotype was stable after multiple sub-cultures without thymol.

RESULTS

Cell morphology studies by scanning electron microscopy (SEM) suggest that thymol renders bacterial cell membranes permeable and disrupts cellular integrity. 1H Nuclear magnetic resonance (NMR) data showed an increase in lactate and the lactic acid family amino acids in the wild type and JM109-Thyr in the presence of thymol, indicating a shift from aerobic respiration to fermentation. Sequencing of JM109-Thyr defined multiple mutations including a stop mutation in the acrR gene resulting in a truncation of the repressor of the AcrAB efflux pump. AcrAB is a multiprotein complex traversing the cytoplasmic and outer membrane, and is involved in antibiotic clearance.

CONCLUSIONS

Our data suggests that thymol tolerance in E. coli induces morphological, metabolic and genetic changes to adapt to thymol antimicrobial activity.

Mathematical modelling for antibiotic resistance control policy: do we know enough?

BACKGROUND

Antibiotics remain the cornerstone of modern medicine. Yet there exists an inherent dilemma in their use: we are able to prevent harm by administering antibiotic treatment as necessary to both humans and animals, but we must be mindful of limiting the spread of resistance and safeguarding the efficacy of antibiotics for current and future generations. Policies that strike the right balance must be informed by a transparent rationale that relies on a robust evidence base.

MAIN TEXT

One way to generate the evidence base needed to inform policies for managing antibiotic resistance is by using mathematical models. These models can distil the key drivers of the dynamics of resistance transmission from complex infection and evolutionary processes, as well as predict likely responses to policy change in silico. Here, we ask whether we know enough about antibiotic resistance for mathematical modelling to robustly and effectively inform policy. We consider in turn the challenges associated with capturing antibiotic resistance evolution using mathematical models, and with translating mathematical modelling evidence into policy.

CONCLUSIONS

We suggest that in spite of promising advances, we lack a complete understanding of key principles. From this we advocate for priority areas of future empirical and theoretical research.

When Both Markets and Governments Fail Health

This paper presents the rationale and motivation for countries and the global development community to tackle a critical set of functions in the health sector that appear to be under-prioritized and underfunded. The recent eruptions of Ebola outbreaks in Africa and other communicable diseases like Zika and SARS elsewhere led scientific and medical commissions to call for global action. The calls for action motivated the World Health Organization (WHO) to respond by defining a new construct within the health sector: Common Good for Health (CGH). While the starting point for developing the CGH construct was the re-emergence of communicable diseases, it extends to additional outcomes resulting from failures to act and finance within and outside the health sector. This paper summarizes global evidence on failures to address CGHs effectively, identifies potential reasons for the public and private sectors' failures to respond, and lays out the first phase of the WHO program as represented by the papers in this special issue of Health Systems & Reform.

Synthesis, antibacterial activity and molecular docking study of vanillin derived 1,4-disubstituted 1,2,3-triazoles as inhibitors of bacterial DNA synthesis

Antimicrobial resistance (AMR) compelled scientists in general while pharmacists, chemists and biologists in specific to believe that we could always remain ahead of the pathogens. The pipeline of new drugs is running gasping and the inducements to develop new antimicrobials to address the global problems of drug resistance are weak. In this pursuit, effective endeavours to prepare new anti-bacterial entities is highly wished. The present study demonstrates successful synthesis of a library of 1,4-disbustituted 1,2,3-triazoles (3a-3k) using Click-chemistry concept and anti-their bacterial potential. In this 1,3-dipolar cycloaddition, the 3-methoxy-4-(prop-2-yn-1-yloxy)benzaldehyde (1) was used as alkyne partner which was synthesized from vanillin and propargyl bromide and further reacted with differently substituted arylpropoxy azides (2a-k) to furnish series of mono and bis1,4-disubstituted-1,2,3-triazoles. All the synthesized compounds were characterized spectroscopically and were evaluated for their initial antimicrobial activity. Preliminary results of antibacterial screening revealed that the synthesized compounds have the highest inhibitory effects compare to the control ciprofloxacin. The compounds 3b and 3g were found to be the most active (MIC: 5 μg/mL, MIC: 10 μg/mL respectively) against various strains of gram-positive and gram-negative bacteria. The molecular docking study against 4GQQ protein with synthesized ligands was performed to see the necessary interactions responsible for anti-bacterial activity. The docking analysis of the most potent compound 3g supported the antibacterial activity exhibiting high inhibition constant and binding energy.

Impact of vaccines on antimicrobial resistance

DRIVERS OF ANTIMICROBIAL RESISTANCE

Antibiotic use drives the development and spread of resistant bacterial infections. Antimicrobial resistance (AMR) has become a prolific global issue, due to significant increases in antibiotic use in humans, livestock and agriculture, inappropriate use (under-dosing and over-prescribing), and misuse of antibiotics (for viral infections where they are ineffective). Fewer new antibiotics are being developed.

THE PROBLEM OF AMR

AMR is now considered a key threat to global health, leading to more mortality and increased healthcare costs threatening future conduct of routine medical procedures. Traditional approaches to address AMR include antibiotic stewardship, better hygiene/infection control, promoting antibiotic research and development, and restricting use for agricultural purposes.

VACCINES AS A TOOL TO REDUCE AMR

While antibiotic development is declining, vaccine technology is growing. This review shows how vaccines can decrease AMR by preventing bacterial and viral infections, thereby reducing the use/misuse of antibiotics, and by preventing antibiotic-resistant infections. Vaccines are less likely to induce resistance. Some future uses and developments of vaccines are also discussed.

CONCLUSIONS

Vaccines, along with other approaches, can help reduce AMR by preventing (resistant) infections and reducing antibiotic use. Industry and governments must focus on the development of novel vaccines and drugs against resistant infections to successfully reduce AMR. A graphical abstract is available online.

Trends and impact of antimicrobial resistance on older inpatients with urinary tract infections (UTIs): A national retrospective observational study

Urinary tract infections (UTIs) are one of the most common infections in older people and are associated with increased morbidity and mortality. UTIs are also associated with increased risk of antimicrobial resistance (AR). This study examined changes in AR among older inpatients with a primary diagnosis of UTIs in the United States over an 8-year period and the impact of AR on clinical outcomes and hospital costs. Data were obtained from the longitudinal hospital HCUP-NIS database from 2009 to 2016 for inpatient episodes that involved those aged 65+ years. The ICD-9 and ICD-10 codes were used to identify episodes with a primary diagnosis of UTIs, comorbidities, AR status and age-adjusted Deyo-Charlson comorbidity index (ACCI) for the patient concerned. Weighted multivariable regression was used to examine the impact of AR on all-cause inpatient mortality, discharge destination, length of stay and hospital expenditures, adjusted for socio-demographic and clinical covariates. The proportion of admissions with AR increased, from 3.64% in 2009 to 6.88% in 2016 (p<0.001), with distinct patterns for different types of resistance. The likelihood of AR was higher in admissions with high ACCI scores and admissions to hospitals in urban areas. Admissions with AR were more likely to be discharged to healthcare facilities (e.g. care homes) compared to routine discharge (OR 1.81; 95%CI, 1.75–1.86), had increased length of stay (1.12 days; 95%CI, 1.06–1.18) and hospital costs (1259 USD; 95%CI, 1178–1340). Resistance due to MRSA was specifically associated with increased hospital mortality (OR 1.33; 95%CI, 1.15–1.53). Our findings suggest that the prevalence of AR has increased among older inpatients with UTIs in the USA. The study highlights the impact of AR among older inpatients with a primary diagnosis of UTIs on clinical outcomes and hospital costs. These relationships and their implications for the care homes to which patients are frequently discharged warrant further research.

Improving the estimation of the global burden of antimicrobial resistant infections

Estimating the global burden of disease from infections caused by pathogens that have acquired antimicrobial resistance (AMR) is essential for resource allocation and to inform AMR action plans at national and global levels. However, the scarcity of robust and accepted methods to determine burden is widely acknowledged. In this Personal View, we discuss the underlying assumptions, characteristics, limitations, and comparability of the approaches used to quantify mortality from AMR bacterial infections. We show that the global burdens of AMR estimated in previous studies are not comparable because of their different methodological approaches, assumptions, and data used to generate the estimates. The analytical frameworks from previous studies are inadequate, and we conclude that a new approach to the estimation of deaths caused by AMR infection is needed. The innovation of a new approach will require the development of mechanisms to systematically collect a clinical dataset of substantial breadth and quality to support the accurate assessment of burden, combined with decision-making and resource allocation for interventions against AMR. We define key actions required and call for innovative thinking and solutions to address these problems.

Economic burden of antibiotic resistance in ESKAPE organisms: a systematic review

Background

Antibiotic resistance (ABR) is one of the biggest threats to global health. Infections by ESKAPE (Enterococcus, S. aureus, K. pneumoniae, A. baumannii, P. aeruginosa, and E. coli) organisms are the leading cause of healthcare-acquired infections worldwide. ABR in ESKAPE organisms is usually associated with significant higher morbidity, mortality, as well as economic burden. Directing attention towards the ESKAPE organisms can help us to better combat the wide challenge of ABR, especially multi-drug resistance (MDR).

Objective

This study aims to systematically review and evaluate the evidence of the economic consequences of ABR or MDR ESKAPE organisms compared with susceptible cases or control patients without infection/colonization in order to determine the impact of ABR on economic burden.

Methods

Both English-language databases and Chinese-language databases up to 16 January, 2019 were searched to identify relevant studies assessing the economic burden of ABR. Studies reported hospital costs (charges) or antibiotic cost during the entire hospitalization and during the period before/after culture among patients with ABR or MDR ESKAPE organisms were included. The costs were converted into 2015 United States Dollars. Disagreements were resolved by a third reviewer.

Results

Of 13,693 studies identified, 83 eligible studies were included in our review. The most studied organism was S. aureus, followed by Enterococcus, A. baumannii, E. coli, E. coli or/and K. pneumoniae, P. aeruginosa, and K. pneumoniae. There were 71 studies on total hospital cost or charge, 12 on antibiotic cost, 11 on hospital cost or charge after culture, 4 on ICU cost, 2 on hospital cost or charge before culture, and 2 on total direct and indirect cost. In general, ABR or MDR ESKAPE organisms are significantly associated with higher economic burden than those with susceptible organisms or those without infection or colonization. Nonetheless, there were no differences in a few studies between the two groups on total hospital cost or charge (16 studies), antibiotic cost (one study), hospital cost before culture (one study), hospital cost after culture (one study). Even, one reported that costs associated with MSSA infection were higher than the costs for similar MRSA cases.

Conclusions

ABR in ESKAPE organisms is not always, but usually, associated with significantly higher economic burden. The results without significant differences may lack statistical power to detect a significant association. In addition, study design which controls for severity of illness and same empirical antibiotic therapy in the two groups would be expected to bias the study towards a similar, even negative result. The review also highlights key areas where further research is needed.

The Clinical and Economic Impact of Antibiotic Resistance in China: A Systematic Review and Meta-Analysis

Antibiotic resistance (ABR) is one of the biggest threats to global health, especially in China. This study aims to analyze the published literature on the clinical and economic impact of ABR or multi-drug resistant (MDR) bacteria compared to susceptible bacteria or non-infection, in mainland China. English and Chinese databases were searched to identify relevant studies evaluating mortality, hospital stay, and hospital costs of ABR. A meta-analysis of mortality was performed using a random effects model. The costs were converted into 2015 United States (US) dollars. Of 13,693 studies identified, 44 eligible studies were included. Twenty-nine investigated the impact of ABR on hospital mortality, 37 were focused on hospital stay, and 21 on hospital costs. Patients with ABR were associated with a greater risk of overall mortality compared to those with susceptibility or those without infection (odds ratio: 2.67 and 3.29, 95% confidence interval: 2.18–3.26 and 1.71–6.33, p < 0.001 and p < 0.001, respectively). The extra mean total hospital stay and total hospital cost were reported, ranging from 3 to 46 days, and from US$238 to US$16,496, respectively. Our study indicates that ABR is associated with significantly higher mortality. Moreover, ABR is not always, but usually, associated with significantly longer hospital stay and higher hospital costs.

Synergistic antibacterial activity of silver nanoparticles and hydrogen peroxide

The increasing challenge of antibiotic resistance requires not only the discovery of new antibiotics, but also the development of new alternative approaches. Herein, the synergistic antibacterial activity of silver nanoparticles and hydrogen peroxide combination is reported. Unlike the bacteriostatic or slightly bactericidal activity achieved by using each agent alone, using these two agents in combination, even at relatively low concentrations, resulted in complete eradication of both the Gram negative Escherichia coli and the Gram positive Staphylococcus aureus in short treatment times indicating a clear synergistic effect between them. Modifying the surface chemistry of silver nanoparticles and the accompanied change in their surface charge enabled a further enhancement of such synergistic effect implying the importance of this aspect. Mechanistically, a Fenton-like reaction between silver nanoparticles and hydrogen peroxide is discussed and hypothesized to be the basis of the observed synergy. Achieving such a significant antibacterial activity at low concentrations reduces the potential toxicity of these agents and hence enables their utilization as an alternative antibacterial approach in wider range of applications.

Physicians' attitude and knowledge regarding antibiotic use and resistance in ambulatory settings

BACKGROUND

The aim of this survey was to assess the attitudes of physicians toward antibiotic prescribing and explore their knowledge about antimicrobial resistance (AMR) in ambulatory care settings.

METHODS

We conducted a cross-sectional survey that was administered to physicians who work primarily in ambulatory care settings in the United States. The survey was self-administered, voluntary, and anonymous, and was delivered through electronic mail and online forums using a 35-item questionnaire.

RESULTS

The survey was completed by 323 physicians. Ninety-nine percent of respondents agreed that AMR is a national problem, but only 63% agreed that AMR is a local problem within their own facilities. Ninety-four percent of the respondents reported that each antibiotic prescription can impact AMR; however, 23% still believed that aggressive prescribing is necessary to avoid clinical failures. Factor perceived to have a low to moderate impact on the physicians' choice of antibiotic was the presence of prescription guidelines (54%). Top measures reported to be effective in reducing the emergence of AMR were institution specific guidelines (94%), institution specific antibiogram (92%), educating health care providers (87%), and regular audits and feedback on antibiotic prescribing (86%).

CONCLUSIONS

AMR awareness campaigns and antibiotic stewardships incorporating interactive education and feedback, along with input of local experts, are critically needed to address the problem of AMR in both inpatient and ambulatory settings.

Methicillin-resistant Staphylococcus aureus (MRSA) in East Africa: red alert or red herring?

BACKGROUND

Methicillin-resistant Staphylococcus aureus (MRSA) is associated with significant morbidity and mortality and has resultant important economic and societal costs underscoring the need for accurate surveillance. In recent years, prevalence rates reported in East Africa have been inconsistent, sparking controversy and raising concern.

METHODS

We described antimicrobial susceptibility patterns of Staphylococcus aureus isolates cultured from patients within the Internal Medicine department of the largest public healthcare facility in East and Central Africa- the Kenyatta National Hospital (KNH) in Nairobi, Kenya. Routine antimicrobial susceptibility data from non-duplicate Staphylococcus aureus isolates cultured between the years 2014-2016 from the medical wards in KNH were reviewed.

RESULTS

Antimicrobial susceptibility data from a total of 187 Staphylococcus aureus isolates revealed an overall MRSA prevalence of 53.4%. Isolates remained highly susceptible to linezolid, tigecycline, teicoplanin and vancomycin.

CONCLUSIONS

The prevalence of MRSA was found to be much higher than that reported in private tertiary facilities in the same region. Careful interrogation of antimicrobial susceptibility results is important to uproot any red herrings and reserve genuine cause for alarm, as this has a critical bearing on health and economic outcomes for a population.

Optimising trial designs to identify appropriate antibiotic treatment durations

BACKGROUND

For many infectious conditions, the optimal antibiotic course length remains unclear. The estimation of course length must consider the important trade-off between maximising short- and long-term efficacy and minimising antibiotic resistance and toxicity.

MAIN BODY

Evidence on optimal treatment durations should come from randomised controlled trials. However, most antibiotic randomised controlled trials compare two arbitrarily chosen durations. We argue that alternative trial designs, which allow allocation of patients to multiple different treatment durations, are needed to better identify optimal antibiotic durations. There are important considerations when deciding which design is most useful in identifying optimal treatment durations, including the ability to model the duration-response relationship (or duration-response 'curve'), the risk of allocation concealment bias, statistical efficiency, the possibility to rapidly drop arms that are clearly inferior, and the possibility of modelling the trade-off between multiple competing outcomes.

CONCLUSION

Multi-arm designs modelling duration-response curves with the possibility to drop inferior arms during the trial could provide more information about the optimal duration of antibiotic therapies than traditional head-to-head comparisons of limited numbers of durations, while minimising the probability of assigning trial participants to an ineffective treatment regimen.

A Payer Perspective of the Hospital Inpatient Additional Care Costs of Antimicrobial Resistance in France: A Matched Case-Control Study

BACKGROUND AND OBJECTIVE

Antimicrobial resistance (AMR) has become one of the biggest threats to global public health given its association with mortality, morbidity and cost of health care. However, little is known on the economic burden of hospitalization attributable to AMR from a public health insurance perspective. We assessed the excess costs to the French public health insurance system attributable to AMR infections in hospitals.

METHODS

Bacterial infectious disease-related hospitalizations were extracted from the National health data information system for all stays occurring in 2015. Bacterial infections, strains, and microbial resistance were identified by specific French ICD-10 codes. Information about health care expenditure, co-morbidities and demographic characteristics (i.e. gender, age) are provided. We used a matched case-control approach to determine the excess of reimbursements paid to stays with AMR compared to stays with an infection without resistance. Cases and controls were matched on gender, age, Charlson comorbidity index, category of infection, infection as principal diagnosis (two classes), microorganism and hospital status. The overall AMR cost was extrapolated to stays with AMR and excluded from the sample (multiple infections), and a second extrapolation was performed to consider stays with unknown resistance status.

RESULTS

The final sample included 52,921 matched-pairs (98.2% cases). Our results suggest that AMR overall cost reached EUR109.3 million in France with a mean of EUR1103 per stay; extrapolation to the entire database shows that the overall cost could potentially reach EUR287.1 million if all cases would be identified. The mean excess length of hospital stay attributable to AMR was estimated at 1.6 days.

CONCLUSION

AMR causes substantial cost burden in France for the public health insurance. Our study confirms the need to reinforce programs to prevent AMR infection and thereby reduce their economic burden.

A simple and feasible antimicrobial stewardship program in a neonatal intensive care unit of a Japanese community hospital

BACKGROUND

Although tertiary hospitals have successfully introduced ASPs by antimicrobial stewardship teams, lots of community hospitals without pediatric infectious disease specialists have difficulty implementing ASP. We present a successful implementation of simple and feasible NICU antimicrobial stewardship program in a Japanese community hospital.

METHOD

We developed a protocol of antimicrobial treatment in our NICU department and have implemented the protocol from September 2017. The protocol consists of start and stop of criteria antimicrobial treatment, weekend report of blood culture result from microbiology department and stopping ordering antimicrobials beforehand for the next day. We compared days of therapy (DOT) during the post-implementation period (September 2017 to August 2018) with that of pre-implementation period (March 2013 to August 2017).

RESULT

In pre- and post-ASP implementation periods, 913 and 194 patients were analyzed. DOT was 175.1 and 41.6/1000 patient-days, respectively (p < 0.001) with 76.2% reduction. The percentage of neonates who had any antimicrobials and the percentage of prolonged antimicrobial treatments among neonates who had any antimicrobials decreased significantly (55.3% vs 20.6%, p < 0.001 and 65.0% vs 32.5%, p < 0.001). The protocol compliance rates were also significantly different (55.4% vs 95.4%; p < 0.001). The methicillin-resistant rate of S.aureus rates were significantly reduced in post-ASP period (31.1% vs 12.9%; p = 0.002).

CONCLUSION

This ASP program was easily implemented in a NICU department of a community hospital and significantly reduced antimicrobial prescription. This kind of simple protocol may be successfully scaled-up in resource limited community hospitals without no pediatric infectious disease specialists or antimicrobial stewardship team.

A peptide derived from rice inhibits alveolar bone resorption via suppression of inflammatory cytokine production

BACKGROUND

Periodontitis is an inflammatory disease that results in alveolar bone resorption due to inflammatory cytokine production induced by bacterial antigens such as lipopolysaccharides (LPS). Here, the preventive effect of the Amyl-1-18 peptide derived from rice in an experimental model of periodontitis and the effect on the anti-inflammatory response were assessed.

METHODS

Alveolar bone resorption, gene transcription of proinflammatory cytokines in the gingiva, and the endotoxin level in the oral cavity were evaluated after oral administration of the Amyl-1-18 peptide for 14 days using a ligature-induced periodontitis model in mice. Additionally, murine macrophages were incubated with LPS of Escherichia coli or Porphyromonas gingivalis in the presence of Amyl-1-18 to analyze the suppressive effects of Amyl-1-18 on the cell signaling pathways associated with proinflammatory cytokine production, including inflammasome activities.

RESULTS

Oral administration of Amyl-1-18 suppressed alveolar bone resorption and gene transcription of interleukin (il)6 in the gingiva of the periodontitis model, and decreased endotoxin levels in the oral cavity, suggesting modulation of periodontal inflammation by inhibition of endotoxin activities in vivo. Also, Amyl-1-18 suppressed IL-6 production induced by LPS and recombinant IL-1β in macrophages in vitro but had no effect on inflammasome activity.

CONCLUSIONS

The Amyl-1-18 peptide from rice inhibited alveolar bone destruction in mouse periodontitis model via suppressing inflammatory cytokine production induced by LPS. It was suggested that Amyl-1-18 peptide has anti-inflammatory property against LPS, not only by neutralization of LPS and subsequent inhibition of nuclear factor-κB signaling but also by inhibition of the IL-1R-related signaling cascade.

Epidemiology and health-economic burden of urinary-catheter-associated infection in English NHS hospitals: a probabilistic modelling study

BACKGROUND

Catheter-associated urinary tract infection (CAUTI) and bloodstream infection (CABSI) are leading causes of healthcare-associated infection in England's National Health Service (NHS), but health-economic evidence to inform investment in prevention is lacking.

AIMS

To quantify the health-economic burden and value of prevention of urinary-catheter-associated infection among adult inpatients admitted to NHS trusts in 2016/17.

METHODS

A decision-analytic model was developed to estimate the annual prevalence of CAUTI and CABSI, and their associated excess health burdens [quality-adjusted life-years (QALYs)] and economic costs (£ 2017). Patient-level datasets and literature were synthesized to estimate population structure, model parameters and associated uncertainty. Health and economic benefits of catheter prevention were estimated. Scenario and probabilistic sensitivity analyses were conducted.

FINDINGS

The model estimated 52,085 [95% uncertainty interval (UI) 42,967-61,360] CAUTIs and 7529 (UI 6857-8622) CABSIs, of which 38,084 (UI 30,236-46,541) and 2524 (UI 2319-2956) were hospital-onset infections, respectively. Catheter-associated infections incurred 45,717 (UI 18,115-74,662) excess bed-days, 1467 (UI 1337-1707) deaths and 10,471 (UI 4783-13,499) lost QALYs. Total direct hospital costs were estimated at £54.4M (UI £37.3-77.8M), with an additional £209.4M (UI £95.7-270.0M) in economic value of QALYs lost assuming a willingness-to-pay threshold of £20,000/QALY. Respectively, CABSI accounted for 47% (UI 32-67%) and 97% (UI 93-98%) of direct costs and QALYs lost. Every catheter prevented could save £30 (UI £20-44) in direct hospital costs and £112 (UI £52-146) in QALY value.

CONCLUSIONS

Hospital catheter prevention is poised to reap substantial health-economic gains, but community-oriented interventions are needed to target the large burden imposed by community-onset infection.

The challenge of antimicrobial resistance: What economics can contribute

As antibiotic consumption grows, bacteria are becoming increasingly resistant to treatment. Antibiotic resistance undermines much of modern health care, which relies on access to effective antibiotics to prevent and treat infections associated with routine medical procedures. The resulting challenges have much in common with those posed by climate change, which economists have responded to with research that has informed and shaped public policy. Drawing on economic concepts such as externalities and the principal–agent relationship, we suggest how economics can help to solve the challenges arising from increasing resistance to antibiotics. We discuss solutions to the key economic issues, from incentivizing the development of effective new antibiotics to improving antibiotic stewardship through financial mechanisms and regulation.

Tridecaptin-inspired antimicrobial peptides with activity against multidrug-resistant Gram-negative bacteria

New tridecaptin analogues are cheaper to make and retain strong Gram-negative activity.

Antimicrobial peptides are a rich source of potential antibiotic candidates. The tridecaptins, a family of linear lipo-tridecapeptides, are easily synthesized and show strong activity against Gram-negative bacteria. However, their composition includes several expensive amino acids, such as d/l diaminobutyric acid and d-allo-isoleucine, significantly increasing their cost of synthesis. Herein, we report a series of new tridecaptin derivatives that are much cheaper to synthesize and retain strong activity against multidrug-resistant Gram-negative bacteria.

Using the best available data to estimate the cost of antimicrobial resistance: a systematic review

Background

Valuation of the economic cost of antimicrobial resistance (AMR) is important for decision making and should be estimated accurately. Highly variable or erroneous estimates may alarm policy makers and hospital administrators to act, but they also create confusion as to what the most reliable estimates are and how these should be assessed. This study aimed to assess the quality of methods used in studies that quantify the costs of AMR and to determine the best available evidence of the incremental cost of these infections.

Methods

In this systematic review, we searched PubMed, Embase, Cinahl, Cochrane databases and grey literature sources published between January 2012 and October 2016. Articles reporting the additional burden of Enterococcus spp., Escherichia coli (E. coli), Klebsiella pneumoniae (K. pneumoniae), Pseudomonas aeruginosa (P. aeruginosa) and Staphylococcus aureus (S. aureus) resistant versus susceptible infections were sourced. The included studies were broadly classified as reporting oncosts from the healthcare/hospital/hospital charges perspective or societal perspective. Risk of bias was assessed based on three methodological components: (1) adjustment for length of stay prior to infection onset and consideration of time-dependent bias, (2) adjustment for comorbidities or severity of disease, and (3) adjustment for inappropriate antibiotic therapy.

Results

Of 1094 identified studies, we identified 12 peer-reviewed articles and two reports that quantified the economic burden of clinically important resistant infections. Two studies used multi-state modelling to account for the timing of infection minimising the risk of time dependent bias and these were considered to generate the best available cost estimates. Studies report an additional CHF 9473 per extended-spectrum beta-lactamases -resistant Enterobacteriaceae bloodstream infections (BSI); additional €3200 per third-generation cephalosporin resistant Enterobacteriaceae BSI; and additional €1600 per methicillin-resistant S. aureus (MRSA) BSI. The remaining studies either partially adjusted or did not consider the timing of infection in their analysis.

Conclusions

Implementation of AMR policy and decision-making should be guided only by reliable, unbiased estimates of effect size. Generating these estimates requires a thorough understanding of important biases and their impact on measured outcomes. This will ensure that researchers, clinicians, and other key decision makers concerned with increasing public health threat of AMR are accurately guided by the best available evidence.

Electronic supplementary material

The online version of this article (10.1186/s13756-019-0472-z) contains supplementary material, which is available to authorized users.

Scaffold hopping computational approach for searching novel β-lactamase inhibitors

We present a novel computational ligand-based virtual screening approach with scaffold hopping capabilities for the identification of novel inhibitors of β-lactamases which confer bacterial resistance to β-lactam antibiotics. The structures of known β-lactamase inhibitors were used as query ligands, and a virtual in silico screening a database of 8 million drug-like compounds was performed in order to select the ligands with similar shape and charge distribution. A set of numerical descriptors was used such as chirality, eigen spectrum of matrices of interatomic distances and connectivity together with higher order moment invariants that showed their efficiency in the field of pattern recognition but have not yet been employed in drug discovery. The developed scaffold-hopping approach was applied for the discovery of analogues of four allosteric inhibitors of serine β-lactamases. After a virtual in silico screening, the effect of two selected ligands on the activity of TEM type β-lactamase was studied experimentally. New non-β-lactam inhibitors were found that showed more effective inhibition of β-lactamases compared to query ligands.

Planning a One Health Case Study to Evaluate Methicillin Resistant Staphylococcus aureus and Its Economic Burden in Portugal

Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most important multidrug-resistant nosocomial pathogens worldwide with infections leading to high rates of morbidity and mortality, a significant burden to human and veterinary clinical practices. The ability of S. aureus colonies to form biofilms on biotic and abiotic surfaces contributes further to its high antimicrobial resistance (AMR) rates and persistence in both host and non-host environments, adding a major ecological dimension to the problem. While there is a lot of information on MRSA prevalence in humans, data about MRSA in animal populations is scarce, incomplete and dispersed. This project is an attempt to evaluate the current epidemiological status of MRSA in Portugal by making a single case study from a One Health perspective. We aim to determine the prevalence of MRSA in anthropogenic sources liable to contaminate different animal habitats. The results obtained will be compiled with existing data on antibiotic resistant staphylococci from Portugal in a user-friendly database, to generate a geographically detailed epidemiological output for surveillance of AMR in MRSA. To achieve this, we will first characterize AMR and genetic lineages of MRSA circulating in northern Portugal in hospital wastewaters, farms near hospitals, farm animals that contact with humans, and wild animals. This will indicate the extent of the AMR problem in the context of local and regional human-animal-environment interactions. MRSA strains will then be tested for their ability to form biofilms. The proteomes of the strains will be compared to better elucidate their AMR mechanisms. Proteomics data will be integrated with the genomic and transcriptomic data obtained. The vast amount of information expected from this omics approach will improve our understanding of AMR in MRSA biofilms, and help us identify new vaccine candidates and biomarkers for early diagnosis and innovative therapeutic strategies to tackle MRSA biofilm-associated infections and potentially other AMR superbugs.

Bacteriophage therapy for management of bacterial infections in veterinary practice: what was once old is new again

Bacteriophages (or phages) are naturally-occurring viruses that can infect and kill bacteria. They are remarkably diverse, numerous and widespread. Each phage has a narrow host range yet a large majority of bacteria studied so far play host to bacteriophages, hence the remarkable phage diversity. Phages were discovered just over 100 years ago and they have been used for treatment of bacterial infections in humans and other animals since the 1920s. They have also been studied intensively and this has led to, and continues to lead to, major insights in the fields of molecular biology and recombinant DNA technology, including that DNA is the genetic material, nucleotides are arranged in triplets to make codons, and messenger RNA is needed for protein synthesis. This article begins with a description of bacteriophages and explains why there has recently been a strong resurgence of interest in their clinical use for treatment of bacterial infections, particularly those caused by organisms resistant to multiple antimicrobial compounds. The history of bacteriophage therapy is briefly reviewed, followed by a review and critique of promising but very limited clinical research on the use of bacteriophages to treat bacterial infections in dogs. Other potential veterinary uses and benefits of bacteriophage therapy are also briefly discussed. There are important practical challenges that will have to be overcome before widespread implementation and commercialisation of bacteriophage therapy can be achieved, which are also considered.