Squeezing the antibiotic balloon: the impact of antimicrobial classes on emerging resistance

Utilizing co-abundances of antimicrobial resistance genes to identify potential co-selection in the resistome

The rapid spread of antimicrobial resistance (AMR) is a threat to global health, and the nature of co-occurring antimicrobial resistance genes (ARGs) may cause collateral AMR effects once antimicrobial agents are used. Therefore, it is essential to identify which pairs of ARGs co-occur. Given the wealth of next-generation sequencing data available in public repositories, we have investigated the correlation between ARG abundances in a collection of 214,095 metagenomic data sets. Using more than 6.76∙108 read fragments aligned to acquired ARGs to infer pairwise correlation coefficients, we found that more ARGs correlated with each other in human and animal sampling origins than in soil and water environments. Furthermore, we argued that the correlations could serve as risk profiles of resistance co-occurring to critically important antimicrobials (CIAs). Using these profiles, we found evidence of several ARGs conferring resistance for CIAs being co-abundant, such as tetracycline ARGs correlating with most other forms of resistance. In conclusion, this study highlights the important ARG players indirectly involved in shaping the resistomes of various environments that can serve as monitoring targets in AMR surveillance programs.

IMPORTANCE

Understanding the collateral effects happening in a resistome can reveal previously unknown links between antimicrobial resistance genes (ARGs). Through the analysis of pairwise ARG abundances in 214K metagenomic samples, we observed that the co-abundance is highly dependent on the environmental context and argue that these correlations can be used to show the risk of co-selection occurring in different settings.

Leveraging Large Data, Statistics, and Machine Learning to Predict the Emergence of Resistant E. coli Infections

Drug-resistant Gram-negative bacterial infections, on average, increase the length of stay (LOS) in U.S. hospitals by 5 days, translating to approximately $15,000 per patient. We used statistical and machine-learning models to explore the relationship between antibiotic usage and antibiotic resistance over time and to predict the clinical and financial costs associated with resistant E. coli infections. We acquired data on antibiotic utilization and the resistance/sensitivity of 4776 microbial cultures at a Kaiser Permanente facility from April 2013 to December 2019. The ARIMA (autoregressive integrated moving average), neural networks, and random forest time series algorithms were employed to model antibiotic resistance trends. The models' performance was evaluated using mean absolute error (MAE) and root mean squared error (RMSE). The best performing model was then used to predict antibiotic resistance rates for the year 2020. The ARIMA model with cefazolin, followed by the one with cephalexin, provided the lowest RMSE and MAE values without signs of overfitting across training and test datasets. The study showed that reducing cefazolin usage could decrease the rate of resistant E. coli infections. Although piperacillin/tazobactam did not perform as well as cefazolin in our time series models, it performed reasonably well and, due to its broad spectrum, might be a practical target for interventions in antimicrobial stewardship programs (ASPs), at least for this particular facility. While a more generalized model could be developed with data from multiple facilities, this study acts as a framework for ASP clinicians to adopt statistical and machine-learning approaches, using region-specific data to make effective interventions.

Chestnut Honey Is Effective against Mixed Biofilms at Different Stages of Maturity

The irresponsible overuse of antibiotics has increased the occurrence of resistant bacterial strains, which represents one of the biggest patient safety risks today. Due to antibiotic resistance and biofilm formation in bacteria, it is becoming increasingly difficult to suppress the bacterial strains responsible for various chronic infections. Honey was proven to inhibit bacterial growth and biofilm development, offering an alternative solution in the treatment of resistant infections and chronic wounds. Our studies included chestnut honey, valued for its high antibacterial activity, and the bacteria Pseudomonas aeruginosa, methicillin-resistant Staphylococcus aureus, and S. epidermidis, known to form multi-species biofilm communities. Minimum inhibitory concentrations (MIC) of chestnut honey were determined for each bacterial strain. Afterwards, the mixed bacterial biofilms were treated with chestnut honey at different stages of maturity (incubation times: 2, 4, 6, 12, 24 h). The extent of biofilm inhibition was measured with a crystal violet assay and demonstrated by scanning electron microscopy (SEM). As the incubation time increased and the biofilm became more mature, inhibition rates decreased gradually. The most sensitive biofilm was the combination MRSA-S. epidermidis, with a 93.5% inhibition rate after 2 h of incubation. Our results revealed that chestnut honey is suitable for suppressing the initial and moderately mature stages of mixed biofilms.

Impact of antimicrobial stewardship implementation on the antibiotic use and susceptibility in a Japanese long-term care hospital

BACKGROUND

Antimicrobial use (AMU) is closely related to the emergence of antimicrobial-resistant (AMR) bacteria. Meanwhile, long-term care hospitals (LTCHs) have been pointed out to be important reservoirs for AMR. However, evidence illustrating the association between AMU and AMR in LTCHs is lacking compared to that of acute care hospitals.

METHODS

We evaluated the impact of an antimicrobial stewardship (AS) program implementation, in a LTCH on AMU and antibiotic susceptibility between three periods: the pre-AS-period (pre-AS); the first period after AS implementation (post-AS 1), in which initiated recommendation the blood culture collection and definitive therapy by AS team; and the second period (post-AS 2), implementation of a balanced use of antibiotics was added.

RESULTS

After the AS implementation, a significant increase in the number of blood cultures collected was observed. Conversely, the AMU of piperacillin-tazobactam (PIPC/TAZ), which has activity against Pseudomonas aeruginosa, was increased and occupied 43.0% of all injectable AMU in post-AS 1 compared with that in pre-AS (35.5%). In the post-AS 2 period, we analyzed the %AUD and recommended hospital-wide PIPC/TAZ sparing; this resulted in the significant reduction in %AUD of PIPC/TAZ, which was associated with improved susceptibility of P. aeruginosa to PIPC/TAZ.

CONCLUSIONS

These results suggest that AS programs aimed at implementing antibiotic sparing may lead to improve AMR, highlighting the necessity of correcting overuse of a single class of antibiotics and usefulness of AMU monitoring in the LTCH setting.

Correlation between antibiotic consumption and resistance of Pseudomonas aeruginosa in a teaching hospital implementing an antimicrobial stewardship program: A longitudinal observational study

BACKGROUND/PURPOSE

The rapid emergence of Pseudomonas aeruginosa resistance made selecting antibiotics more challenge. Antimicrobial stewardship programs (ASPs) are urging to implant to control the P. aeruginosa resistance. The purpose of this study is to evaluate the relationship between antimicrobial consumption and P. aeruginosa resistance, the impact of ASPs implemented during the 14-year study period.

METHODS

A total 14,852 P. aeruginosa isolates were included in our study. The resistant rate and antimicrobial consumption were investigated every six months. Linear regression analysis was conducted to examine the trends in antibiotics consumption and antimicrobial resistance over time. The relationship between P. aeruginosa resistance and antimicrobial consumption were using Pearson correlation coefficient to analysis. The trend of resistance before and after ASPs implanted is evaluated by segment regression analysis.

RESULTS

P. aeruginosa resistance to ceftazidime, gentamicin, amikacin, ciprofloxacin and levofloxacin significantly decreased during the study period; piperacillin/tazobactam (PTZ), cefepime, imipenem/cilastatin and meropenem remained stable. The P. aeruginosa resistance to ciprofloxacin and levofloxacin increasing initial then decreased after strictly controlled the use of levofloxacin since 2007. As the first choice antibiotic to treat P. aeruginosa, the consumption and resistance to PTZ increase yearly and resistance became stable since extended-infusion therapy policy implant in 2009.

CONCLUSION

Our ASP intervention strategy, which included extended infusion of PTZ and restrict use of levofloxacin, may be used to control antimicrobial resistance of P. aeruginosa in medical practice.

Clinical and Ecological Impact of an Educational Program to Optimize Antibiotic Treatments in Nursing Homes (PROA-SENIOR): A Cluster, Randomized, Controlled Trial and Interrupted Time-Series Analysis

BACKGROUND

Antimicrobial stewardship programs (ASPs) are recommended in nursing homes (NHs), although data are limited. We aimed to determine the clinical and ecological impact of an ASP for NHs.

METHODS

We performed a cluster, randomized, controlled trial and a before-after study with interrupted time-series analyses in 14 NHs for 30 consecutive months from July 2018 to December 2020 in Andalusia, Spain. Seven facilities implemented an ASP with a bundle of 5 educational measures (general ASP) and 7 added 1-to-1 educational interviews (experimental ASP). The primary outcome was the overall use of antimicrobials, calculated monthly as defined daily doses (DDD) per 1000 resident days (DRD).

RESULTS

The total mean antimicrobial consumption decreased by 31.2% (-16.72 DRD; P = .045) with respect to the preintervention period; the overall use of quinolones and amoxicillin-clavulanic acid dropped by 52.2% (P = .001) and 42.5% (P = .006), respectively; and the overall prevalence of multidrug-resistant organisms (MDROs) decreased from 24.7% to 17.4% (P = .012). During the intervention period, 12.5 educational interviews per doctor were performed in the experimental ASP group; no differences were found in the total mean antimicrobial use between groups (-14.62 DRD; P = .25). Two unexpected coronavirus disease 2019 waves affected the centers increasing the overall mean use of antimicrobials by 40% (51.56 DRD; P < .0001).

CONCLUSIONS

This study suggests that an ASP for NHs appears to be associated with a decrease in total consumption of antimicrobials and prevalence of MDROs. This trial did not find benefits associated with educational interviews, probably due to the coronavirus disease 2019 pandemic. Clinical Trials Registration. NCT03543605.

Biofilms in wound healing: A bibliometric and visualised study

Bibliometric analyses are often used as a means of visualising the knowledge base and associated trends and patterns in a target scientific field based on a quantitative review of the corresponding literature. In this study, we explore the current status of research pertaining to biofilms in wound healing and elucidate trends in this research space. Through this process, we gain insight into findings from papers indexed in the Web of Science Core Collection. These references were then analysed and plotted using Microsoft Excel 2019, VOSviewer, and CiteSpace V. The results provide a fresh perspective regarding global trends and hotspots in biofilm-related wound healing research. These findings also offer a foundation that researchers can use to identify active hotspots of scientific interest to guide further research endeavours.

Association between Antimicrobial Consumption and the Prevalence of Nosocomial Carbapenem-Resistant Escherichia coli and Klebsiella pneumoniae in a Tertiary Hospital in Northern Taiwan

Carbapenem-resistant Enterobacteriales has become a threat in Taiwan. This is the first local study focusing on the association between carbapenem-resistant Enterobacteriales and antimicrobial consumption. From January 2012 to December 2020, data were collected in a tertiary care hospital in Taipei, Taiwan. Antimicrobial consumption was estimated by the defined daily dose/1,000 patient-days. During the same period, the prevalence of carbapenem-resistant Escherichia coli (CREC) and carbapenem-resistant Klebsiella pneumoniae (CRKP) were collected through routine surveillance data. The following retrospective analyses were conducted: 1) analysis of antimicrobial consumption over time, (2) analysis and forecast of CREC and CRKP prevalence over time, and 3) analysis of correlation between antimicrobial consumption and the prevalence of CREC and CRKP. The consumption of piperacillin/tazobactam (β = 0.615), fluoroquinolones (β = 0.856), meropenem (β = 0.819), and doripenem (β = 0.891) increased during the observation period (P < 0.001), and the consumption of aminoglycosides (β = -0.852) and imipenem/cilastatin (β = -0.851) decreased (P < 0.001). The prevalence of CRKP rose over time (β = 0.522, P = 0.001) and correlated positively with the consumption of fluoroquinolones, levofloxacin, penicillin/β-lactamase inhibitor, piperacillin/tazobactam, meropenem, and doripenem (P < 0.05). The prevalence of CRKP and CREC both correlated negatively with consumption of aminoglycosides (P < 0.01). The prevalence of CRKP in our hospital increased as the forecast predicted based on an autoregressive integrated moving average model. This study provides alarming messages for members participating in antimicrobial stewardship programs, including the increasing prevalence of CRKP, the increasing consumption of broad-spectrum antibiotics, and the positive correlation between them.

Assessment of preauthorization and 24-hour expert consultation as a restrictive antimicrobial stewardship bundle in a Brazilian tertiary-care hospital: an interrupted time series analysis

Background

Worldwide, healthcare facilities face high and often inappropriate consumption of antimicrobials. However, there are limited antimicrobial stewardship (ASP) studies from low- and middle-income countries that include restrictive measures and their impacts on antimicrobial consumption.

Aim

This study aims to assess the impact of a restrictive bundle (preauthorization requirements and offering consultation with an infectious diseases physician 24 hours a day) on antimicrobial consumption, in a tertiary hospital in Brazil.

Methods

We conducted an interrupted time series analysis (ITS) with pharmacy-based data from January 2010 to December 2018 to evaluate changes of level and slope in antimicrobial consumption (expressed in DDD/1,000 patient-days) after the implementation of the restrictive bundle in September 2014. Fourteen restricted antimicrobials (amphotericin B deoxycholate, liposomal amphotericin B, micafungin, voriconazole, ganciclovir, amikacin, ampicillin/sulbactam, daptomycin, ertapenem, levofloxacin, linezolid, piperacillin/tazobactam, polymyxin B, and tigecycline) and eight unrestricted were analysed.

Findings

Among the 14 restricted antimicrobials, four presented a significant negative level change: micafungin (-2,14, p=.027), voriconazole (-14.72, p<.001), ertapenem (-1.89, p=.007) and amikacin (-13.98, p<.001). The only negative slope change was observed for the liposomal amphotericin B, -0.532 (p=.009). The restricted antibiotics group presented an increased consumption trend (1.068, p=.002) compared to the pre-intervention period, a similar change was observed for the unrestricted antibiotics group (1.360, p<.001).

Conclusion

Preauthorization and 24 hour expert consultation were partially effective as a restrictive antimicrobial stewardship bundle in a Brazilian tertiary-care hospital. Increased consumption of unrestricted antimicrobials was observed as a side effect of the intervention.

Prevalence and Patterns of Antimicrobial Resistance among Escherichia coli and Staphylococcus spp. in a Veterinary University Hospital

The occurrence of antimicrobial resistance in commensal strains of Escherichia coli and Staphylococcus spp. was investigated in 320 samples collected from patients and the environment of a veterinary university hospital-specifically, the consultation area (CA) and intensive care unit (ICU). E. coli was isolated in 70/160 samples (44%), while Staphylococcus spp. were isolated in 110/160 (69%) samples. The occurrence of multidrug-resistant (MDR) isolates from CA and ICU admission were similar for E. coli (1/12 (8%) versus 4/27 (15%), respectively) and Staphylococcus spp. (10/19 (53%) versus 26/50 (52%), respectively). MDR E. coli isolates increased significantly at hospital discharge (18/31; 58%; p = 0.008). Antimicrobial treatment administered during hospitalization was a risk factor for carriage of MDR E. coli (OR, 23.9; 95% CI: 1.18-484.19; p = 0.04) and MDR Staphylococcus spp. (OR, 19.5; 95% CI 1.30-292.76; p = 0.02), respectively. The odds ratio for MDR E. coli was 41.4 (95% CI 2.13-806.03; p = 0.01), if the administration of fluoroquinolones was evaluated. The mecA gene was detected in 19/24 (79%) coagulase-positive Staphylococcus spp. isolates resistant to oxacillin. High rates of MDR Staphylococcus spp. were reported. Hospitalization in the ICU and antimicrobial treatment were risk factors for colonization by MDR commensal bacteria.

Impact of an empiric antimicrobial therapy manual on antimicrobial usage and multidrug resistant organism trends in a large Italian teaching hospital

Aim

To evaluate the changes in antimicrobial consumption and multidrug-resistant microorganism trends after introducing an empiric antimicrobial therapy manual to support antimicrobial stewardship.

Methods

A 4-year prospective interventional study assessed the effect of introducing an empiric antimicrobial therapy manual in medical and surgical wards during two periods: pre-intervention period (January 2015–May 2017) and post-intervention period (June 2017–December 2019). Outcomes included microorganism trends of bloodstream infections (BSI) for Klebsiella pneumoniae carbapenemase-producing bacteria (KPC), extended spectrum beta-lactamase ESBL-E. coli, meticillin-resistant Staphylococcus aureus (MRSA) and Candida albicans. Also, Clostridioides difficile infection (CDI) episodes were included. Rates were normalised per 1000 patient-days (PD). Antimicrobial consumption was assessed as defined daily dose (DDD)/1000 PD in interrupted time series analysis.

Results

In medical wards, we observed a significant decrease in the consumption of piperacillin-tazobactam and a decrease in the trends of tigecycline and vancomycin consumption. In surgical wards, there was a significant decrease in consumption of fluoroquinolones and piperacillin-tazobactam. This decrease was maintained in trend for all the antimicrobials but was significant for tigecycline only. In medical wards, there was a significant reduction of MRSA and C. albicans. In surgical wards, we observed a decrease in MRSA, ESBL-E. coli, C. albicans and CDI. KPC cases decreased by 22.5% in medical wards and 74.3% in surgical wards.

Conclusion

The results suggest that a persuasive educational approach to antimicrobial stewardship, with the introduction of an empiric antimicrobial manual and continuous education, resulted in reductions in both antimicrobial use and healthcare-associated BSI caused by multidrug-resistant organisms. More studies with longer follow up are needed to investigate the effect of antimicrobial stewardship on clinical outcomes.

Temporal association between antibiotic use and resistance in Gram-negative bacteria

The β-lactam/lactamase inhibitors (BLBLIs) combination drugs are considered an effective alternative to carbapenems. However, there is a growing concern that the increased use of BLBLIs may lead to increased resistance. This study determined the temporal association between the consumption of BLBLI and the antimicrobial resistance in Gram-negative bacteria. In this retrospective study, electronic data on the Gram-negative bacterial isolates, including A. baumannii, P. aeruginosa, E. coli, and K. pneumoniae from in-patients and susceptibility testing results were retrieved from the medical records of the clinical laboratory. A linear regression and cross-correlation analysis were performed on the acquired data. Increasing trends (p<0.05) in the consumption of BIBLI and carbapenem with a median use of 27.68 and 34.46 DDD/1000 PD per quarter were observed, respectively. A decreased trend (p=0.023) in the consumption of fluoroquinolones with a median use of 29.13 DDD/1000 PD per quarter was observed. The resistance rate of K. pneumoniae was synchronized with the BIBLI and carbapenem consumptions with a correlation coefficient of 0.893 (p=0.012) and 0.951 (p=0.016), respectively. The cross-correlation analysis against the consumption of BIBLI and meropenem resistant K. pneumoniae was peaked at 0-quarter lag (r=951, p=0.016). There was an increasing trend in the consumption of BLBLI and carbapenems. The increasing trend in the rates of resistance to piperacillin/tazobactam, in line with the increasing consumption of BLBLI, suggests that BLBLI has to be used with caution and cannot be directly considered as a long-term alternative to carbapenems.

Change-points in antibiotic consumption in the community, European Union/European Economic Area, 1997-2017

OBJECTIVES

Surveillance of antibiotic consumption in the community is of utmost importance to inform and evaluate control strategies. Data on two decades of antibiotic consumption in the community were collected from 30 EU/European Economic Area (EEA) countries. This article reviews temporal trends and the presence of abrupt changes in subgroups of relevance in antimicrobial stewardship.

METHODS

For the period 1997-2017, data on yearly antibiotic consumption in the community, aggregated at the level of the active substance, were collected using the WHO ATC classification and expressed in DDD (ATC/DDD index 2019) per 1000 inhabitants per day. We applied a range of non-linear mixed models to assess the presence of changes in the consumption of antibacterials for systemic use (ATC group J01) and eight antibiotic subgroups.

RESULTS

For the majority of the studied groups, a country-specific change-point model provided the best fit. Depending on the antibiotic group/subgroup and on the country, change-points were spread out between 2000 and 2013.

CONCLUSIONS

Due to the heterogeneity in antibiotic consumption in the community across EU/EEA countries, a country-specific change-point model provided the better fit. Given the limitations of this model, our recommendation for the included countries is to carefully interpret the country-specific results presented in this article and to use the tutorial included in this series to conduct their own change-point analysis when evaluating the impact of changes in regulations, public awareness campaigns, and other national interventions to improve antibiotic consumption in the community.

Do specific antimicrobial stewardship interventions have an impact on carbapenem resistance in Gram-negative bacilli? A multicentre quasi-experimental ecological study: time-trend analysis and characterization of carbapenemases

BACKGROUND

Carbapenem-resistant Gram-negative bacilli (CR-GNB) are among the most threatening microorganisms worldwide and carbapenem use facilitates their spread. Antimicrobial stewardship programmes (ASPs) can help to optimize the use of antibiotics. This study evaluates the impact of a multifaceted educational ASP on carbapenem use and on the epidemiology of CR-GNB.

METHODS

We conducted a quasi-experimental, time-series study in seven hospitals, from January 2014 to September 2018. The key intervention was composed of educational interviews promoting the appropriate use of carbapenems. The primary endpoints were carbapenem consumption and incidence density (ID) of CR-GNB. All non-duplicated CR-GNB clinical isolates were tested using phenotypic assays and PCR for the presence of carbapenemases. Joinpoint regression and interrupted time-series analyses were used to determine trends.

RESULTS

A decrease in carbapenem consumption throughout the study period [average quarterly percentage change (AQPC) -1.5%, P < 0.001] and a -8.170 (-16.064 to -0.277) level change following the intervention were observed. The ID of CR-Acinetobacter baumannii decreased (AQPC -3.5%, P = 0.02) and the overall ID of CR-GNB remained stable (AQPC -0.4%, P = 0.52). CR-GNB, CR-Pseudomonas aeruginosa and CR-A. baumannii IDs per hospital correlated with the local consumption of carbapenems. The most prevalent carbapenem resistance mechanisms were OXA-23 for CR-A. baumannii (76.1%), OXA-48 for CR-Klebsiella pneumoniae (66%) and no carbapenemases for CR-P. aeruginosa (91.7%). The epidemiology of carbapenemases was heterogeneous throughout the study, especially for carbapenemase-producing Enterobacteriaceae.

CONCLUSIONS

In conclusion, a multifaceted, educational interview-based ASP targeting carbapenem prescribing reduced carbapenem use and the ID of CR-A. baumannii.

Characterization of the antibacterial activity from ethanolic extracts of the botanical, Larrea tridentata

Background

β-lactam antibiotics are a class of broad-spectrum antibiotics consisting of all antibiotic agents that contain a β-lactam ring in their molecular structures. β-lactam antibiotics are only known to be isolated from fungi (e.g. Acremonium chrysogenum, Penicillium chrysogenum and Aspergillus nidulans) and bacteria (e.g. Streptomyces clavuligerus). We have shown that botanical extracts prepared from Larrea tridentata have strong antimicrobial activity against several bacteria, including members of Staphylococcus and Streptococcus genera.

Methods

Through resistance studies, inhibitor assays, and ELISA testing, we demonstrated L. tridentata extracts may contain a β-lactam type antibiotic activity.

Results

Based on the estimated β-lactam concentration within the extract, the antimicrobial activity of the L. tridentata extract was approximately 2000–8000-fold greater against Staphylococcus as compared to other β-lactams, penicillin or ampicillin. In the L. tridentata extract, this increased activity was found to be associated with the likely presence of a cofactor leading to increased potentiation of the β-lactam activity. This potentiation activity was also observed to enhance the activity of exogenously added natural penicillin antibiotics.

Conclusions

Although constituents were not isolated in this study, the results obtained strongly support the presence of β-lactam type antibiotic activity and antibiotic potentiation activity present in ethanolic extracts prepared from L. tridentata.

Evolution of the Gram-Negative Antibiotic Resistance Spiral over Time: A Time-Series Analysis

We followed up the interplay between antibiotic use and resistance over time in a tertiary-care hospital in Hungary. Dynamic relationships between monthly time-series of antibiotic consumption data (defined daily doses per 100 bed-days) and of incidence densities of Gram-negative bacteria (Escherichia coli, Klebsiella spp., Pseudomonas aeruginosa, and Acinetobacter baumannii) resistant to cephalosporins or carbapenems were followed using vector autoregressive models sequentially built of time-series ending in 2015, 2016, 2017, 2018, and 2019. Relationships with Gram-negative bacteria as a group were fairly stable across years. At species level, association of cephalosporin use and cephalosporin resistance of E. coli was shown in 2015–2017, leading to increased carbapenem use in these years. Association of carbapenem use and carbapenem resistance, as well as of carbapenem resistance and colistin use in case of A. baumannii, were consistent throughout; associations in case of Klebsiella spp. were rarely found; associations in case of P. aeruginosa varied highly across years. This highlights the importance of temporal variations in the interplay between changes in selection pressure and occurrence of competing resistant species.

Impact of an Antimicrobial Stewardship Program on the Incidence of Carbapenem Resistant Gram-Negative Bacilli: An Interrupted Time-Series Analysis

Carbapenem-resistant Gram-negative bacilli (CR-GNB) are a critical public health threat, and carbapenem use contributes to their spread. Antimicrobial stewardship programs (ASPs) have proven successful in reducing antimicrobial use. However, evidence on the impact of carbapenem resistance remains unclear. We evaluated the impact of a multifaceted ASP on carbapenem use and incidence of CR-GNB in a high-endemic hospital. An interrupted time-series analysis was conducted one year before and two years after starting the ASP to assess carbapenem consumption, CR-GNB incidence, death rates of sentinel events, and other variables potentially related to CR-GNB incidence. An intense reduction in carbapenem consumption occurred after starting the intervention and was sustained two years later (relative effect -83.51%; 95% CI -87.23 to -79.79). The incidence density of CR-GNB decreased by -0.915 cases per 1000 occupied bed days (95% CI -1.743 to -0.087). This effect was especially marked in CR-Klebsiella pneumoniae and CR-Escherichia coli, reversing the pre-intervention upward trend and leading to a relative reduction of -91.15% (95% CI -105.53 to -76.76) and -89.93% (95% CI -107.03 to -72.83), respectively, two years after starting the program. Death rates did not change. This ASP contributed to decreasing CR-GNB incidence through a sustained reduction in antibiotic use without increasing mortality rates.

The Use of Colistin in Food-Producing Animals in Estonia-Vaccination as an Effective Alternative to Consumption of Critically Important Antimicrobials in Pigs

Reducing the use of critically important antimicrobials in veterinary medicine is increasingly important to avoid the development and spread of antimicrobial resistance. The aim of this study was to analyse ten-year trends of colistin consumption in Estonia and to ascertain the possible association between Escherichia (E.) coli vaccination and colistin consumption in pig production. Colistin sales data (2010-2019) were collected from the wholesalers, allowing differentiation of target species. In Estonia, the amount of sold colistin increased constantly and almost doubled from 2010 to 2013, and decreased from 2013 to 2019 by 92.5% in total. On average across a ten-year study period, 89.7% of colistin was used in pig production. The number of sold doses of E. coli vaccines for pigs was very low before 2014 (<2000) and increased drastically to 2019 (362,000). According to linear time-series model with autoregressive integrated moving average (ARIMA) the consumption of colistin in pigs decreased on average by 0.23 mg/PCU for every 10,000 E. coli vaccine doses (95% CI -0.39, -0.06; p = 0.006) over ten years. This study revealed that in pig production, vaccination against E. coli strains contributes to the expected downward trend in colistin consumption.

Impact of cascade reporting of antimicrobial susceptibility on fluoroquinolone and meropenem consumption at a Veterans' Affairs medical center

OBJECTIVE

To determine whether cascade reporting is associated with a change in meropenem and fluoroquinolone consumption.

DESIGN

A quasi-experimental study was conducted using an interrupted time series to compare antimicrobial consumption before and after the implementation of cascade reporting.

SETTING

A 399-bed, tertiary-care, Veterans' Affairs medical center.

PARTICIPANTS

Antimicrobial consumption data across 8 inpatient units were extracted from the Center for Disease Control and Prevention (CDC) National Health Safety Network (NHSN) antimicrobial use (AU) module from April 2017 through March 2019, reported as antimicrobial days of therapy (DOT) per 1,000 days present (DP).

INTERVENTION

Cascade reporting is a strategy of reporting antimicrobial susceptibility test results in which secondary agents are only reported if an organism is resistant to primary, narrow-spectrum agents. A multidisciplinary team developed cascade reporting algorithms for gram-negative bacteria based on local antibiogram and infectious diseases practice guidelines, aimed at restricting the use of fluoroquinolones and carbapenems. The algorithms were implemented in March 2018.

RESULTS

Following the implementation of cascade reporting, mean monthly meropenem (P =.005) and piperacillin/tazobactam (P = .002) consumption decreased and cefepime consumption increased (P < .001). Ciprofloxacin consumption decreased by 2.16 DOT per 1,000 DP per month (SE, 0.25; P < .001). Clostridioides difficile rates did not significantly change.

CONCLUSION

Ciprofloxacin consumption significantly decreased after the implementation of cascade reporting. Mean meropenem consumption decreased after cascade reporting was implemented, but we observed no significant change in the slope of consumption. cascade reporting may be a useful strategy to optimize antimicrobial prescribing.

Association of Antibiotic Use with the Resistance Epidemiology of Pseudomonas aeruginosa in a Hospital Setting: A Four-Year Retrospective Time Series Analysis

Background: Even though, Pseudomonas aeruginosa is a common cause of hospital-acquired infections, treatment is challenging because of decreasing rates of susceptibility to many broad-spectrum antibiotics. Methods: Consumption data of eight broad spectrum antimicrobial agents and resistance rates of P. aeruginosa were collected for 48 consecutive months. Autoregressive integrated moving average (ARIMA) and transfer functions models were used to develop relationships between antibiotic use and resistance. Results: Positive correlations between P. aeruginosa resistance and uses of ciprofloxacin (p < 0.001), meropenem (p < 0.001), and cefepime (p = 0.005) were identified. Transfer function models showed the quantified effect of each of these antibiotics on resistance. Regarding levofloxacin, ceftazidime, piperacillin/tazobactam and imipenem, no significant relationships were found. For ceftazidime and levofloxacin, this was probably due to their low consumption, while for imipenem the reason can possibly be ascribed to the already high established P. aeruginosa resistance in the hospital. Conclusion: In the hospital setting, the effect of antimicrobial agents’ consumption on the susceptibility epidemiology of P. aeruginosa differs significantly for each one of them. In this study, the role of precedent use of meropenem, cefepime and ciprofloxacin was quantified in the development of P. aeruginosa resistance.

Impact of daily versus weekly service of infectious diseases consultation on hospital antimicrobial consumption: a retrospective study

BACKGROUND

To verify whether a daily service of Infectious Diseases consultation (ID-cons) is more effective than a weekly service in reducing antibiotic (ATB) consumption without worsening of clinical outcomes.

METHODS

Two-year observational analysis of the ID-cons provided in a hospital setting in Milan, Italy. ID-cons resulted in: start-of-ATB; no-ATB; confirmation; modification-of-ATB. The impact of a weekly (September 1, 2016 - August 31, 2017 versus a daily (September 1, 2017 - September 30, 2018) service of ID-cons was evaluated in terms of: time-from-admission-to-first-ID-cons, type of ATB-intervention and number-of-ID-cons per 100 bed-days (bd). Primary outcomes: reduction of hospital ATB consumption overall and by department and classes expressed as Defined Daily Dose (DDD)/100bd (by Wilcoxon test for paired data).

SECONDARY OUTCOMES

overall and sepsis-related in-hospital annual mortality rates (as death/patient's admissions).

RESULTS

Overall 2552 ID-cons in 1111 patients (mean, 2.3 ID-cons per patient) were performed (18.6% weekly vs 81.4% daily). No differences in patient characteristics were observed. In the daily-service, compared to the weekly-service, patients were seen by the ID-consultant earlier (time-from-admission-to-ID-cons: 6 days (IQR 2-13) vs 10 days (IQR 6-19), p < 0.001) and ATB was more often started by the ID-consultant (Start-of-ATB: 11.6% vs 8%, p = 0.02), rather than treating physicians. After switching to daily-service, the number-of-ID-cons increased from 0.4/100bd to 1.5/100bd (p = 0.01), with the greatest increase in the emergency department (1.5/100bd vs 6.7/100bd, p < 0.001). Total ATB consumption decreased from 64 to 60 DDD/100bd. As for the number-of-cons, the consumption of ATB decreased mainly in the emergency area. According to ATB classes, glycopeptides consumption was reduced from 3.1 to 2.1 DDD/100bd (p = 0.02) while carbapenem use decreased from 3.7 to 3.1 DDD/100bd (p = 0.07). No changes in overall mortality (5.2% vs 5.2%) and sepsis-related mortality (19.3% vs 20.9%; p = 0.7) were observed among the two time-period.

CONCLUSIONS

Daily-ID-cons resulted in a more comprehensive management of the infected patient by the ID-consultant, especially in the emergency area where we also observed the highest rate of reduction of ATB-usage. No change in mortality was observed.

Post-Prescription Review with Threat of Infectious Disease Consultation and Sustained Reduction in Meropenem Use Over Four Years

BACKGROUND

Following a meropenem shortage, we implemented a post-prescription review with feedback (PPRF) in November 2015 with mandatory infectious disease (ID) consultation for all meropenem and imipenem courses > 72 hours. Providers were made aware of the policy via an electronic alert at the time of ordering.

METHODS

A retrospective study was conducted at the University of Washington Medical Center (UWMC) and Harborview Medical Center (HMC) to evaluate the impact of the policy on antimicrobial consumption and clinical outcomes pre- and post-intervention during a 6-year period. Antimicrobial use was tracked using days of therapy (DOT) per 1,000 patient-days, and data were analyzed by an interrupted time series.

RESULTS

There were 4,066 and 2,552 patients in the pre- and post-intervention periods, respectively. Meropenem and imipenem use remained steady until the intervention, when a marked reduction in DOT/1,000 patient-days occurred at both hospitals (UWMC: percentage change -72.1%, (95% CI -76.6, -66.9), P & 0.001; HMC: percentage change -43.6%, (95% CI -59.9, -20.7), P = 0.001). Notably, although the intervention did not address antibiotic use until 72 hours after initiation, there was a significant decline in meropenem and imipenem initiation ("first starts") in the post-intervention period, with a 64.9% reduction (95% CI 58.7, 70.2; P &0.001) at UWMC and 44.7% reduction (95% CI 28.1, 57.4; P & 0.001) at HMC.

CONCLUSIONS

Mandatory ID consultation and PPRF for meropenem and imipenem beyond 72 hours resulted in a significant and sustained reduction in the use of these antibiotics and notably impacted their up-front usage.

The effect of an antibiotic stewardship program on tigecycline use in a Tertiary Care Hospital, an intervention study

Background

A drug-oriented antibiotic stewardship intervention targeting tigecycline utilization was launched at Makassed General Hospital, Beirut, Lebanon, in 2016 as a part of a comprehensive Antibiotic Stewardship Program (ASP). In this study, we evaluated the effect of this intervention on changing tigecycline prescription behavior in different types of infections, patient outcome and mortality, along with tigecycline drug use density, when compared to an earlier period before the initiation of ASP.

Methods

This is a retrospective chart review of all adult inpatients who received tigecycline for more than 72 h between Jan-2012 and Dec-2013 [period (P) 1 before ASP] and between Oct-2016 and Dec-2018 [period (P) 2 during ASP].

Results

Tigecycline was administered to 153 patients during P1 and 116 patients during P2. The proportion of patients suffering from cancer, those requiring mechanical ventilation, and those with hemodynamic failure was significantly reduced between P1 and P2. The proportion of patients who received tigecycline for FDA-approved indications increased from 19% during P1 to 78% during P2 (P < 0.001). On the other hand, its use in off-label indications was restricted, including ventilator-associated pneumonia (26.1% in P1, 3.4% in P2, P < 0.001), hospital-acquired pneumonia (19.6% in P1, 5.2% in P2, P = 0.001), sepsis (9.2% in P1, 3% in P2, P = 0.028), and febrile neutropenia (15.7% in P1, 0.9% in P2, P < 0.001). The clinical success rate of tigecycline therapy showed an overall significant increase from 48.4% during P1 to 65.5% during P2 (P = 0.005) in the entire patient population. All-cause mortality in the tigecycline-treated patients decreased from 45.1% during P1 to 20.7% during P2 (P < 0.0001). In general, mean tigecycline consumption decreased by 55% between P1 and P2 (P < 0.0001).

Conclusion

The drug-oriented ASP intervention targeting tigecycline prescriptions improved its use and patient outcomes, where it helped curb the over-optimistic use of this drug in off-label indications where it is not a suitable treatment option.

What Makes Wounds Chronic

Chronic wounds present a unique therapeutic challenge to heal. Chronic wounds are colonized with bacteria and the presence of a biofilm that further inhibits the normal wound healing processes, and are locked into a very damaging proinflammatory response. The treatment of chronic wounds requires a coordinated approach, including debridement of devitalized tissue, minimizing bacteria and biofilm, control of inflammation, and the use of specialized dressings to address the specific aspects of the particular nonhealing ulcer.

Nudging In MicroBiology Laboratory Evaluation (NIMBLE): A scoping review

BACKGROUND

Nudging in microbiology is an antimicrobial stewardship strategy to influence decision making through the strategic reporting of microbiology results while preserving prescriber autonomy. The purpose of this scoping review was to identify the evidence that demonstrates the effectiveness of nudging strategies in susceptibility result reporting to improve antimicrobial use.

METHODS

A search for studies in Ovid MEDLINE, Embase, PsycINFO, and All EBM Reviews was conducted. All simulated and vignette studies were excluded. Two independent reviewers were used throughout screening and data extraction.

RESULTS

Of a total of 1,346 citations screened, 15 relevant studies were identified. Study types included pre- and postintervention (n = 10), retrospective cohort (n = 4), and a randomized controlled trial (n = 1). Most studies were performed in acute-care settings (n = 13), and the remainder were in primary care (n = 2). Most studies used a strategy to alter the default antibiotic choices on the antibiotic report. All studies reported at least 1 outcome of antimicrobial use: utilization (n = 9), appropriateness (n = 7), de-escalation (n = 2), and cost (n = 1). Moreover, 12 studies reported an overall benefit in antimicrobial use outcomes associated with nudging, and 4 studies evaluated the association of nudging strategy with subsequent antimicrobial resistance, with 2 studies noting overall improvement.

CONCLUSIONS

The number of heterogeneous studies evaluating the impact of applying nudging strategies to susceptibility result reports is small; however, most strategies do show promise in altering prescriber's antibiotic selection. Selective and cascade reporting of targeted agents in a hospital setting represent the majority of current research. Gaps and opportunities for future research identified from our scoping review include performing prospective randomized controlled trials and evaluating other approaches aside from selective reporting.

High versus low intensity: What is the optimal approach to prospective audit and feedback in an antimicrobial stewardship program?

BACKGROUND

Antimicrobial stewardship program (ASP) interventions, such as prospective audit and feedback (PAF), have been shown to reduce antimicrobial use and improve patient outcomes. However, the optimal approach to PAF is unknown.

OBJECTIVE

We examined the impact of a high-intensity interdisciplinary rounds-based PAF compared to low-intensity PAF on antimicrobial use on internal medicine wards in a 400-bed community hospital.

METHODS

Prior to the intervention, ASP pharmacists performed low-intensity PAF with a focus on targeted antibiotics. Recommendations were made directly to the internist for each patient. High-intensity, rounds-based PAF was then introduced sequentially to 5 internal medicine wards. This PAF format included twice-weekly interdisciplinary rounds, with a review of all internal medicine patients receiving any antimicrobial agent. Antibiotic use and clinical outcomes were measured before and after the transition to high-intensity PAF. An interrupted time-series analysis was performed adjusting for seasonal and secular trends.

RESULTS

With the transition from low-intensity to high-intensity PAF, a reduction in overall usage was seen from 483 defined daily doses (DDD)/1,000 patient days (PD) during the low-intensity phase to 442 DDD/1,000 PD in the high-intensity phase (difference, -42; 95% confidence interval [CI], -74 to -9). The reduction in usage was more pronounced in the adjusted analysis, in the latter half of the high intensity period, and for targeted agents. There were no differences seen in clinical outcomes in the adjusted analysis.

CONCLUSIONS

High-intensity PAF was associated with a reduction in antibiotic use compared to a low-intensity approach without any adverse impact on patient outcomes. A decision to implement high-intensity PAF approach should be weighed against the increased workload required.

Optimizing design of research to evaluate antibiotic stewardship interventions: consensus recommendations of a multinational working group

BACKGROUND

Antimicrobial stewardship interventions and programmes aim to ensure effective treatment while minimizing antimicrobial-associated harms including resistance. Practice in this vital area is undermined by the poor quality of research addressing both what specific antimicrobial use interventions are effective and how antimicrobial use improvement strategies can be implemented into practice. In 2016 we established a working party to identify the key design features that limit translation of existing research into practice and then to make recommendations for how future studies in this field should be optimally designed. The first part of this work has been published as a systematic review. Here we present the working group's final recommendations.

METHODS

An international working group for design of antimicrobial stewardship intervention evaluations was convened in response to the fourth call for leading expert network proposals by the Joint Programming Initiative on Antimicrobial Resistance (JPIAMR). The group comprised clinical and academic specialists in antimicrobial stewardship and clinical trial design from six European countries. Group members completed a structured questionnaire to establish the scope of work and key issues to develop ahead of a first face-to-face meeting that (a) identified the need for a comprehensive systematic review of study designs in the literature and (b) prioritized key areas where research design considerations restrict translation of findings into practice. The working group's initial outputs were reviewed by independent advisors and additional expertise was sought in specific clinical areas. At a second face-to-face meeting the working group developed a theoretical framework and specific recommendations to support optimal study design. These were finalized by the working group co-ordinators and agreed by all working group members.

RESULTS

We propose a theoretical framework in which consideration of the intervention rationale the intervention setting, intervention features and the intervention aims inform selection and prioritization of outcome measures, whether the research sets out to determine superiority or non-inferiority of the intervention measured by its primary outcome(s), the most appropriate study design (e.g. experimental or quasi- experimental) and the detailed design features. We make 18 specific recommendation in three domains: outcomes, objectives and study design.

CONCLUSIONS

Researchers, funders and practitioners will be able to draw on our recommendations to most efficiently evaluate antimicrobial stewardship interventions.

Metabolic modelling of chronic wound microbiota predicts mutualistic interactions that drive community composition

AIMS

To identify putative mutualistic interactions driving community composition in polymicrobial chronic wound infections using metabolic modelling.

METHODS AND RESULTS

We developed a 12 species metabolic model that covered 74% of 16S rDNA pyrosequencing reads of dominant genera from 2963 chronic wound patients. The community model was used to predict species abundances averaged across this large patient population. We found that substantially improved predictions were obtained when the model was constrained with genera prevalence data and predicted abundances were averaged over 5000 ensemble simulations with community participants randomly determined according to the experimentally determined prevalences. Staphylococcus and Pseudomonas were predicted to exhibit a strong mutualistic relationship that resulted in community growth rate and diversity simultaneously increasing, suggesting that these two common chronic wound pathogens establish dominance by cooperating with less harmful commensal species. In communities lacking one or both dominant pathogens, other mutualistic relationship including Staphylococcus/Acinetobacter, Pseudomonas/Serratia and Streptococcus/Enterococcus were predicted consistent with published experimental data.

CONCLUSIONS

Mutualistic interactions were predicted to be driven by crossfeeding of organic acids, alcohols and amino acids that could potentially be disrupted to slow chronic wound disease progression.

SIGNIFICANCE AND IMPACT OF THE STUDY

Approximately 2% of the US population suffers from nonhealing chronic wounds infected by a combination of commensal and pathogenic bacteria. These polymicrobial infections are often resilient to antibiotic treatment due to the nutrient-rich wound environment and species interactions that promote community stability and robustness. The simulation results from this study were used to identify putative mutualistic interactions between bacteria that could be targeted to enhance treatment efficacy.

Challenges and opportunities for antimicrobial stewardship in resource-rich and resource-limited countries

Introduction: Inappropriate prescription practices, patient and provider knowledge and attitudes, variable availability of diagnostic and surveillance systems, and the unrestricted use of antimicrobials in animals and plants are contributory factors to the global crisis of antimicrobial resistance (AMR). Areas covered: Notwithstanding that interventions to revert AMR should be tailored to the socio-politico-economic landscape, there is a global consensus for the implementation and enhancement of antimicrobial stewardship strategies. Yet the implementation of Antimicrobial Stewardship Programs (ASPs) remains relatively limited within healthcare settings and faces complex challenges in resource-limited countries. The current review summarizes the limitations of current ASPs, translation challenges in resource-limited countries, and potential solutions. Expert opinion: Suboptimal ASP implementation in hospitals is multifactorial. Restriction of antimicrobial use should be informed by risk-benefit analyses, including the potential for substitute prescribing, and displacement of selection pressures. Thresholds in population use of antibiotics above which AMR increases may provide quantitative targets for ASPs. Horizontal and vertical collaborations involving policymakers and the general public are of paramount importance. While impactful prescribing changes require sustained engagement of the public and health-care professionals, we warn against over-estimating the benefits of behavioral interventions. We advocate for population-level stewardship interventions in addition to investment in structural factors that will aid ASP implementation.

A nonlinear time-series analysis approach to identify thresholds in associations between population antibiotic use and rates of resistance

Balancing access to antibiotics with the control of antibiotic resistance is a global public health priority. At present, antibiotic stewardship is informed by a 'use it and lose it' principle, in which antibiotic use by the population is linearly related to resistance rates. However, theoretical and mathematical models suggest that use-resistance relationships are nonlinear. One explanation for this is that resistance genes are commonly associated with 'fitness costs' that impair the replication or transmissibility of the pathogen. Therefore, resistant genes and pathogens may only gain a survival advantage where antibiotic selection pressures exceed critical thresholds. These thresholds may provide quantitative targets for stewardship-optimizing the control of resistance while avoiding over-restriction of antibiotics. Here, we evaluated the generalizability of a nonlinear time-series analysis approach for identifying thresholds using historical prescribing and microbiological data from five populations in Europe. We identified minimum thresholds in temporal relationships between the use of selected antibiotics and incidence rates of carbapenem-resistant Acinetobacter baumannii (Hungary), extended-spectrum β-lactamase-producing Escherichia coli (Spain), cefepime-resistant E. coli (Spain), gentamicin-resistant Pseudomonas aeruginosa (France) and methicillin-resistant Staphylococcus aureus (Northern Ireland) in different epidemiological phases. Using routinely generated data, our approach can identify context-specific quantitative targets for rationalizing population antibiotic use and controlling resistance. Prospective intervention studies that restrict antibiotic consumption are needed to validate these thresholds.

Antibiotic consumption and resistance of gram-negative pathogens (collateral damage)

Antibiotics are commonly prescribed in community and hospital care. Overuse and misuse favors emergence and spread of resistant bacteria. The ATC/DDD methodology is commonly used for presenting the drug utilization data. In primary care, the consumption is usually expressed in DDD per 1,000 inhabitants per day, in hospital, preferably in DDD per 100 bed days and DDD per 100 admissions. The alternative metric is days of therapy (DOT), which needs IT support. Antibiotics have ecological adverse effects at individual and population level. Antibiotics select resistant bacteria among pathogens and normal flora. Broad-spectrum antibiotics, low dosage and prolonged antibiotic therapy favor the development of resistance. Although total use of antibiotics in hospital is much less than in the community, the intensity of use magnified by cross infection ensures a multitude of resistant bacteria in today's hospitals. Reversal of resistance is complex and might persist for many years despite the introduction of antimicrobial containment and stewardship programs.

Temporal association between antibiotic use and resistance in Klebsiella pneumoniae at a tertiary care hospital

Background

β-Lactam/β-lactamase inhibitors (BLBLIs) were introduced into clinical practice as an alternative to carbapenems for treating multi-drug-resistant Klebsiella pneumoniae infections. However, little is known about the relationship between BLBLI treatment and antimicrobial resistance. In this study, we investigated the trends and the temporal association between antibiotic use and antimicrobial resistance in K. pneumoniae isolates obtained between 2012 and 2016.

Methods

Data regarding quarterly consumption (total number of prescriptions per quarter) of all BLBLIs, all third-generation cephalosporins, and all fluoroquinolones at a tertiary care hospital were obtained from the Korean Health Insurance Review and Assessment Service. Susceptibility data (isolation rate of antibiotic resistance per quarter) were obtained from the existing database of the same tertiary hospital. Regression analysis was used to analyze annual trends and cross-correlations to assess the temporal association on a quarterly basis between antibiotic consumption and antibiotic resistance in K. pneumoniae.

Results

The rate of resistance to piperacillin/tazobactam in K. pneumoniae significantly increased over the study period (p < 0.01). The consumption of all BLBLIs was also found to be significantly correlated with the rate of resistance to piperacillin/tazobactam (β = 0.66; p < 0.01), ceftazidime (β = 0.54; p = 0.02), and levofloxacin (β = - 0.60; p = 0.01) with two-quarter lags. Furthermore, the consumption of all third-generation cephalosporins was significantly correlated with rates of K. pneumoniae resistance to ceftazidime (β = 0.64; p < 0.01) with a two-quarter lag and levofloxacin (β = 0.50; p = 0.03) with a quarter lag. The consumption of all fluoroquinolones correlated with resistance rates to ceftazidime (β = 0.14; p < 0.01) with a two-quarter lag.

Conclusions

The rate of resistance to piperacillin/tazobactam in K. pneumoniae increased significantly over the study period and was significantly correlated with BLBLI consumption. While BLBLIs can potentially be utilized as an alternative to carbapenems, our findings reinforce concerns of resistance to these drugs. Further research is needed to understand the implications on resistance of utilizing BLBLIs as a carbapenem-sparing option.

Fluoroquinolone Restriction as an Effective Antimicrobial Stewardship Intervention

PURPOSE OF REVIEW

Fluoroquinolones are a commonly prescribed antibiotic class that has come under scrutiny in recent years due to mounting evidence of association between adverse drug events, C. difficile infection and isolation of antibiotic-resistant bacteria.

RECENT FINDINGS

Inpatient antimicrobial stewardship (AMS) programs have a toolbox of potential interventions to curb inappropriate antibiotic use, prevent antibiotic-associated adverse drug events, and avoid unnecessary costs of care. Fluoroquinolone restriction policies in the acute care setting have demonstrated beneficial effects, including decreased rates of C. difficile infection and ESBL-producing Enterobacteriaceae. However, a simple blanket restriction policy may "squeeze the antibiotic balloon" and will likely be insufficient if not implemented in conjunction with other AMS interventions. There is a growing body of evidence to support formulary restriction of fluoroquinolones in the acute care setting to decrease rates of C. difficile infection and development of ESBL-producing organisms. Data on how to best implement these restrictions or how to implement outside of acute care settings is limited.

Alginate membranes loaded with hyaluronic acid and silver nanoparticles to foster tissue healing and to control bacterial contamination of non-healing wounds

Chronic non-healing wounds are a clinically important problem in terms of number of patients and costs. Wound dressings such as hydrogels, hydrocolloids, polyurethane films and foams are commonly used to manage these wounds since they tend to maintain a moist environment which is shown to accelerate re-epithelialization. The use of antibacterial compounds is important in the management of wound infections. A novel wound-dressing material based on a blended matrix of the polysaccharides alginate, hyaluronic acid and Chitlac-silver nanoparticles is here proposed and its application for wound healing is examined. The manufacturing approach to obtain membranes is based on gelling, foaming and freeze-casting of alginate, hyaluronic acid and Chitlac-silver nanoparticles mixtures using calcium ions as the cross-linking agent. Comprehensive evaluations of the morphology, swelling kinetics, permeability, mechanical characteristics, cytotoxicity, capability to inhibit metalloproteinases and of antibacterial property were conducted. Biological in vitro studies demonstrated that hyaluronic acid released by the membrane is able to stimulate the wound healing meanwhile the metal silver exploits an efficient antibacterial activity against both planktonic bacteria and biofilms. Overall, the experimental data evidence that the studied material could be used as antibacterial wound dressing for wound healing promotion.

Formulation, stabilisation and encapsulation of bacteriophage for phage therapy

Against a backdrop of global antibiotic resistance and increasing awareness of the importance of the human microbiota, there has been resurgent interest in the potential use of bacteriophages for therapeutic purposes, known as phage therapy. A number of phage therapy phase I and II clinical trials have concluded, and shown phages don't present significant adverse safety concerns. These clinical trials used simple phage suspensions without any formulation and phage stability was of secondary concern. Phages have a limited stability in solution, and undergo a significant drop in phage titre during processing and storage which is unacceptable if phages are to become regulated pharmaceuticals, where stable dosage and well defined pharmacokinetics and pharmacodynamics are de rigueur. Animal studies have shown that the efficacy of phage therapy outcomes depend on the phage concentration (i.e. the dose) delivered at the site of infection, and their ability to target and kill bacteria, arresting bacterial growth and clearing the infection. In addition, in vitro and animal studies have shown the importance of using phage cocktails rather than single phage preparations to achieve better therapy outcomes. The in vivo reduction of phage concentration due to interactions with host antibodies or other clearance mechanisms may necessitate repeated dosing of phages, or sustained release approaches. Modelling of phage-bacterium population dynamics reinforces these points. Surprisingly little attention has been devoted to the effect of formulation on phage therapy outcomes, given the need for phage cocktails, where each phage within a cocktail may require significantly different formulation to retain a high enough infective dose. This review firstly looks at the clinical needs and challenges (informed through a review of key animal studies evaluating phage therapy) associated with treatment of acute and chronic infections and the drivers for phage encapsulation. An important driver for formulation and encapsulation is shelf life and storage of phage to ensure reproducible dosages. Other drivers include formulation of phage for encapsulation in micro- and nanoparticles for effective delivery, encapsulation in stimuli responsive systems for triggered controlled or sustained release at the targeted site of infection. Encapsulation of phage (e.g. in liposomes) may also be used to increase the circulation time of phage for treating systemic infections, for prophylactic treatment or to treat intracellular infections. We then proceed to document approaches used in the published literature on the formulation and stabilisation of phage for storage and encapsulation of bacteriophage in micro- and nanostructured materials using freeze drying (lyophilization), spray drying, in emulsions e.g. ointments, polymeric microparticles, nanoparticles and liposomes. As phage therapy moves forward towards Phase III clinical trials, the review concludes by looking at promising new approaches for micro- and nanoencapsulation of phages and how these may address gaps in the field.

A Comprehensive Review of Topical Odor-Controlling Treatment Options for Chronic Wounds

The process of wound healing is often accompanied by bacterial infection or critical colonization, resulting in protracted inflammation, delayed reepithelization, and production of pungent odors. The malodor produced by these wounds may lower health-related quality of life and produce psychological discomfort and social isolation. Current management focuses on reducing bacterial activity within the wound site and absorbing malodorous gases. For example, charcoal-based materials have been incorporated into dressing for direct adsorption of the responsible gases. In addition, multiple topical agents, including silver, iodine, honey, sugar, and essential oils, have been suggested for incorporation into dressings in an attempt to control the underlying bacterial infection. This review describes options for controlling malodor in chronic wounds, the benefits and drawbacks of each topical agent, and their mode of action. We also discuss the use of subjective odor evaluation techniques to assess the efficacy of odor-controlling therapies. The perspectives of employing novel biomaterials and technologies for wound odor management are also presented.

Synthesized zinc peroxide nanoparticles (ZnO2-NPs): a novel antimicrobial, anti-elastase, anti-keratinase, and anti-inflammatory approach toward polymicrobial burn wounds

Increasing of multidrug resistance (MDR) remains an intractable challenge for burn patients. Innovative nanomaterials are also in high demand for the development of new antimicrobial biomaterials that inevitably have opened new therapeutic horizons in medical approaches and lead to many efforts for synthesizing new metal oxide nanoparticles (NPs) for better control of the MDR associated with the polymicrobial burn wounds. Recently, it seems that metal oxides can truly be considered as highly efficient inorganic agents with antimicrobial properties. In this study, zinc peroxide NPs (ZnO₂-NPs) were synthesized using the co-precipitation method. Synthesized ZnO₂-NPs were characterized by X-ray diffraction, Fourier transformed infrared, transmission electron microscopy, thermogravimetric analysis, differential scanning calorimetry, and ultraviolet-visible spectroscopy. The characterization techniques revealed synthesis of the pure phase of non-agglomerated ZnO₂-NPs having sizes in the range of 15–25 nm with a transition temperature of 211°C. Antimicrobial activity of ZnO₂-NPs was determined against MDR Pseudomonas aeruginosa (PA) and Aspergillus niger (AN) strains isolated from burn wound infections. Both strains, PA6 and AN4, were found to be more susceptible strains to ZnO₂-NPs. In addition, a significant decrease in elastase and keratinase activities was recorded with increased concentrations of ZnO₂-NPs until 200 µg/mL. ZnO₂-NPs revealed a significant anti-inflammatory activity against PA6 and AN4 strains as demonstrated by membrane stabilization, albumin denaturation, and proteinase inhibition. Moreover, the results of in vivo histopathology assessment confirmed the potential role of ZnO₂-NPs in the improvement of skin wound healing in the experimental animal models. Clearly, the synthesized ZnO₂-NPs have demonstrated a competitive capability as antimicrobial, anti-elastase, anti-keratinase, and anti-inflammatory candidates, suggesting that the ZnO₂-NPs are promising metal oxides that are potentially valued for biomedical applications.

Preferential Use of Nitrofurantoin Over Fluoroquinolones for Acute Uncomplicated Cystitis and Outpatient Escherichia coli Resistance in an Integrated Healthcare System

OBJECTIVES To evaluate changes in outpatient fluoroquinolone (FQ) and nitrofurantoin (NFT) use and resistance among E. coli isolates after a change in institutional guidance to use NFT over FQs for acute uncomplicated cystitis. DESIGN Retrospective preintervention-postintervention study. SETTING Urban, integrated healthcare system. PATIENTS Adult outpatients treated for acute cystitis. METHODS We compared 2 time periods: January 2003-June 2007 when FQs were recommended as first-line therapy, and July 2007-December 2012, when NFT was recommended. The main outcomes were changes in FQ and NFT use and FQ- and NFT-resistant E. coli by time-series analysis. RESULTS Overall, 5,714 adults treated for acute cystitis and 11,367 outpatient E. coli isolates were included in the analysis. After the change in prescribing guidance, there was an immediate 26% (95% CI, 20%-32%) decrease in FQ use (P<.001), and a nonsignificant 6% (95% CI, -2% to 15%) increase in NFT use (P=.12); these changes were sustained over the postintervention period. Oral cephalosporin use also increased during the postintervention period. There was a significant decrease in FQ-resistant E. coli of -0.4% per quarter (95% CI, -0.6% to -0.1%; P=.004) between the pre- and postintervention periods; however, a change in the trend of NFT-resistant E. coli was not observed. CONCLUSIONS In an integrated healthcare system, a change in institutional guidance for acute uncomplicated cystitis was associated with a reduction in FQ use, which may have contributed to a stabilization in FQ-resistant E. coli. Increased nitrofurantoin use was not associated with a change in NFT resistance. Infect Control Hosp Epidemiol 2017;38:461-468.

Chronic Wound Biofilms: Pathogenesis and Potential Therapies

Chronic wounds are a growing medical problem that cause high rates of morbidity and mortality, costing the healthcare industry in the United States millions of dollars annually. Chronic wound healing is hampered by the presence of bacterial infections that form biofilms, in which the bacteria are encased in exopolysaccharide (EPS) and are less metabolically active than their free-living counterparts. Bacterial biofilms make chronic wounds more refractory to treatment and slow tissue repair by stimulating chronic inflammation at the wound site. Bacterial species communicate through a mechanism known as quorum sensing (QS) to regulate and coordinate the gene expression that is important for virulence-factor production, including biofilm formation. This review focuses on the relationships between chronic wounds, biofilms, and QS in the virulence of chronic-wound pathogens.

Role of ribomunyl((r)) in the prevention of recurrent respiratory tract infections in adults : overview of clinical results

Recurrent respiratory tract infections (RRTIs) in adults are the result of an imbalance between lung defense mechanisms, and bacterial burden. Antibacterial treatments can temporarily restore the equilibrium between host and bacterial load, but do not prevent recurrence of infection. An alternative approach to prevent recurrence of infection is treatment with an immunostimulant, which provides immune protection against repeated bacterial and viral infection. All immunostimulant products are bacterial in origin: lysates (first generation immunostimulants), or bacterial extracts, like bacterial ribosomes, or membrane proteoglycans. This review highlights the current state of knowledge regarding the use of immunostimulants in adults with RRTIs, taking the ribosomal immunostimulant Ribomunyl((R)) as an example. Many studies are available on the mechanism of action and clinical efficacy in prevention of RRTIs in adults treated with Ribomunyl((R)). The effect of this immunostimulant on anti-infectious responses is explained by a stimulation of both nonspecific (innate) and specific (adaptive) immunity. In order to obtain a global overview of the therapeutic efficacy of Ribomunyl((R)) the most pertinent trials were selected from the literature based on adequate patient numbers and good methodology. Results of double-blind placebo-controlled trials using Ribomunyl((R)) for the treatment of different upper or lower RRTIs have demonstrated a statistically significant reduction in the number of infectious episodes and as a consequence, a decrease in antibacterial consumption, after 3 and 6 months of treatment. The tolerance profile of Ribomunyl((R)) was good in all studies. Economic evaluations suggest that savings can be made in healthcare expenditure, in patients with recurrent episodes of infection. It is concluded that Ribomunyl((R)) is effective in preventing and reducing upper and lower respiratory tract infections in adults. The product may also have an impact on reducing the development of bacterial resistance, as a result of fewer courses of antibacterials required to treat patients with RRTIs.

Evaluation of wound healing, anti-microbial and antioxidant potential of Pongamia pinnata in wistar rats

Objective

To investigate wound healing, antimicrobial and antioxidant activity of leaf extract of Pongamia Pinnata.

Materials and methods

Methanolic extracts of P. pinnata leaf were studied for wound healing efficiency, and was assessed by the rate of wound contraction, tensile strength, breaking strength, hydroxyproline and hexosamine content, along with its effect on pro-inflammatory and anti-inflammatory cytokines was assessed using excision and incision model of wound repair in Wistar rats. Antimicrobial activity against ten microorganisms was also assessed. In vivo antioxidant activity was performed to understand the mechanism of wound healing potency.

Results

The results indicated that P. pinnata extract has potent wound healing capacity as evident from the wound contraction and increased tensile strength. Hydroxyproline and hexosamine expression were also well correlated with the healing pattern observed. extract exhibited significant antimicrobial activity, Staphylococcus aureus, Staphylococcus pyogenes, Staphylococcus epidermidis, Escherichia coli, Micrococcus luteus, Enterobacter aerogenes, Salmonella typhi, Pseudomonas aeruginosa, Candida albicans, Aspergillus niger also indicate that P. pinnata posses potent antioxidant activity by inhibition lipid peroxidation, reduce glutathione, superoxide dismutase level and increases catalase activity. During early wound healing phase TNF-α and IL-6 level were found to be up-regulated by P. pinnata treatment.

Conclusion

Increased wound contraction and tensile strength, augmented hydroxyproline and hexosamine content, antioxidative activity and moderate antimicrobial activity support the early wound healing exhibited by P. pinnata. Induction in cytokine production may be one of the mechanisms in accelerating the wound healing. Results suggest that P. pinnata may be useful in tropical management of wound healing.

Influence of antimicrobial consumption on gram-negative bacteria in inpatients receiving antimicrobial resistance therapy from 2008-2013 at a tertiary hospital in Shanghai, China

BACKGROUND

Irrational use of antimicrobial agents is a major cause of increased antimicrobial resistance. Effective antibiotic stewardship strategies nationwide or in local health care settings are necessary to reduce antibiotic use and bacteria resistance.

METHODS

We evaluated the effectiveness of China's antimicrobial stewardship policy on antimicrobial use and applied time-series analysis methodology to determine the temporal relationship between antibiotic use and gram-negative bacteria resistance at Changhai Hospital from 2008-2013. Isolates investigated included Escherichia coli, Klebsiella pneumoniae, Acinetobacter baumannii, and Pseudomonas aeruginosa.

RESULTS

Consumption of 7 restricted-use antibiotics was dramatically reduced. Resistance to ceftazidime in P aeruginosa and A baumannii and resistance to ciprofloxacin in P aeruginosa significantly decreased. By using cross-correlation analysis, associations between ciprofloxacin resistance in P aeruginosa and fluoroquinolones consumption (r = 0.48; lag = 0; P = .02), ceftazidime resistance in P aeruginosa and third-generation cephalosporins consumption (r = 0.54; lag = -1; P = .01) were identified. No substantial association between other pairs was found.

CONCLUSIONS

Enhanced nationwide antimicrobial stewardship campaigns launched in 2011 have made great achievements in regard to antibiotic use but have had limited effects on the reversal of gram-negative bacteria resistance in health care settings. Sound infection prevention and control programs to reduce the transmission of resistant pathogens for hospitals in China are urgently needed.

Antibiotic stewardship programmes in intensive care units: Why, how, and where are they leading us

Antibiotic usage and increasing antimicrobial resistance (AMR) mount significant challenges to patient safety and management of the critically ill on intensive care units (ICU). Antibiotic stewardship programmes (ASPs) aim to optimise appropriate antibiotic treatment whilst minimising antibiotic resistance. Different models of ASP in intensive care setting, include “standard” control of antibiotic prescribing such as “de-escalation strategies”through to interventional approaches utilising biomarker-guided antibiotic prescribing. A systematic review of outcomes related studies for ASPs in an ICU setting was conducted. Forty three studies were identified from MEDLINE between 1996 and 2014. Of 34 non-protocolised studies, [1 randomised control trial (RCT), 22 observational and 11 case series], 29 (85%) were positive with respect to one or more outcome: These were the key outcome of reduced antibiotic use, or ICU length of stay, antibiotic resistance, or prescribing cost burden. Limitations of non-standard antibiotic initiation triggers, patient and antibiotic selection bias or baseline demographic variance were identified. All 9 protocolised studies were RCTs, of which 8 were procalcitonin (PCT) guided antibiotic stop/start interventions. Five studies addressed antibiotic escalation, 3 de-escalation and 1 addressed both. Six studies reported positive outcomes for reduced antibiotic use, ICU length of stay or antibiotic resistance. PCT based ASPs are effective as antibiotic-stop (de-escalation) triggers, but not as an escalation trigger alone. PCT has also been effective in reducing antibiotic usage without worsening morbidity or mortality in ventilator associated pulmonary infection. No study has demonstrated survival benefit of ASP. Ongoing challenges to infectious disease management, reported by the World Health Organisation global report 2014, are high AMR to newer antibiotics, and regional knowledge gaps in AMR surveillance. Improved AMR surveillance data, identifying core aspects of successful ASPs that are transferable, and further well-conducted trials will be necessary if ASPs are to be an effective platform for delivering desired patient outcomes and safety through best antibiotic policy.