Implementation and evaluation of an antimicrobial stewardship programme in companion animal clinics: A stepped-wedge design intervention study.

BACKGROUND: To curb increasing resistance rates, responsible antimicrobial use (AMU) is needed, both in human and veterinary medicine. In human healthcare, antimicrobial stewardship programmes (ASPs) have been implemented worldwide to improve appropriate AMU. No ASPs have been developed for and implemented in companion animal clinics yet.
OBJECTIVES: The objective of the present study was to implement and evaluate the effectiveness of an ASP in 44 Dutch companion animal clinics. The objectives of the ASP were to increase awareness on AMU, to decrease total AMU whenever possible and to shift AMU towards 1st choice antimicrobials, according to Dutch guidelines on veterinary AMU.
METHODS: The study was designed as a prospective, stepped-wedge, intervention study, which was performed from March 2016 until March 2018. The multifaceted intervention was developed using previous qualitative and quantitative research on current prescribing behaviour in Dutch companion animal clinics. The number of Defined Daily Doses for Animal (DDDAs) per clinic (total, 1st, 2nd and 3rd choice AMU) was used to quantify systemic AMU. Monthly AMU data were described using a mixed effect time series model with auto-regression. The effect of the ASP was modelled using a step function and a change in the (linear) time trend.
RESULTS: A statistically significant decrease of 15% (7%-22%) in total AMU, 15% (5%-24%) in 1st choice AMU and 26% (17%-34%) in 2nd choice AMU was attributed to participation in the ASP, on top of the already ongoing time trends. Use of 3rd choice AMs did not significantly decrease by participation in the ASP. The change in total AMU became more prominent over time, with a 16% (4%-26%) decrease in (linear) time trend per year.
CONCLUSIONS: This study shows that, although AMU in Dutch companion animal clinics was already decreasing and changing, AMU could be further optimised by participation in an antimicrobial stewardship programme.

Introduction

The increase of antimicrobial resistance (AMR) is recognised as a threat for modern medicine and public health [1]. To help control AMR, responsible use of antimicrobials (AMs) is warranted and a decrease in inappropriate use of AMs is necessary, both in human and veterinary medicine [1-3].

In human medicine, the term antimicrobial stewardship programme (ASP) generally refers to specific programmes or series of interventions to monitor and direct antimicrobial use (AMU) at the hospital or primary care level [4-7]. In veterinary medicine, it usually encompasses numerous elements of improved AMU (e.g., increasing awareness of (inter)national practice guidelines, use of diagnostic microbiology and use of alternatives to AMs) and it is often associated with country-wide surveillance of AMU and development of (inter)national guidelines on AMU [8].

In Dutch food producing animals, a combination of compulsory and voluntary actions resulted in a 64% reduction in AMU (between 2008 and 2017). A decrease in resistance rates was observed as well [9-12]. Just since the end of 2011 onwards, more attention is being paid to AMU in companion animals. Legislation (2013) on mandatory susceptibility testing for veterinary use of 3rd choice AMs also holds for companion animals [13]. The Royal Dutch Veterinary Association promotes the use of guidelines on AMU as well.

A survey on prescription data of 68 companion animal clinics in the Netherlands (during 2009–2011) showed that the use of 3rd generation cephalosporins and fluoroquinolones (i.e. highest priority critically important antimicrobials for human medicine according to the World Health Organisation (WHO)) accounted for 18% of total AMU, based upon the number of Defined Daily Doses for Animals [14,15]. During the past years, AMU in Dutch companion animal clinics has been decreasing (with 19% when comparing 2012 to 2014) [16]. However, especially with regard to the (sub)classes of AMs used, there is still room left for improvement. According to Dutch classification of veterinary AMU, 2nd choice AMs (i.e. mainly aminopenicillins and 1st and 2nd generation cephalosporins) still accounted for 43% of total AMU and 3rd choice AMs (i.e. 3rd generation cephalosporins and fluoroquinolones) for 8% of total AMU in 2014 [16].

Antimicrobial prescribing behaviour can only be improved if interventions are attuned to the specific situation and the target group, and factors influencing antimicrobial prescribing are taken into account [17,18]. Qualitative research in Dutch companion animal clinics indicated that antimicrobial prescribing behaviour is influenced by four main categories of factors: veterinarian-related factors, patient-related factors, treatment-related factors and contextual factors [19]. These categories of factors were taken into account when the intervention elements of the present study were developed. The aim of this study was to implement and evaluate the effectiveness of such a customised ASP, aiming to improve antimicrobial prescribing, in 44 Dutch companion animal clinics.

Materials and methods

Study design

The Antimicrobial Stewardship and Pets-study (ASAP) was designed as a prospective, stepped-wedge intervention study aiming to optimise antimicrobial prescribing in Dutch companion animal clinics by implementing an antimicrobial stewardship programme. The intervention study was performed from March 2016 until March 2018.

Time schedule

Clinics, divided into four clusters, were offered all separate intervention elements of the ASP. The period considered as the actual “intervention period” comprised 12 months: from start of implementation of the ASP (i.e. filling in patient evaluation forms) up to 4–5 months after the feedback meeting (i.e. when clinics started filling in patient evaluation forms for the second time). Time schedule of the applied stepped-wedge design is shown in Fig 1. The first cluster of clinics was contacted in December 2015, their intervention period started in March 2016. The intervention period of the last cluster started in January 2017. The clinics were grouped into four clusters based on their geographic location.

Fig 1

Time schedule of the applied stepped-wedge design.

The time schedule indicates the start and the duration of the period considered as the “intervention period” for the four separate clusters of participating clinics.

Participating clinics

Sample size

The study aimed at including at least 40 clinics. This number was based on a power calculation which indicated that with 40 clinics a minimal change of 8% in mean total AMU could be detected with a power of 0.80 (= beta) and a significance of 0.05 (= alpha) over a one-year period. Calculations were based on AMU data at clinic level from a previous study conducted in 68 Dutch companion animal clinics [15].

Clinic selection

Companion animal clinics were approached for participation using the database of the Royal Dutch Veterinary Association (KNMvD) containing all Dutch veterinary clinics. The clinics were sampled based upon previous shown interest to participate in a study on optimisation of AMU in companion animal clinics and on geographic location.

Clinics were invited by e-mail, followed a week later by a phone call to answer questions and to arrange a visit. Ultimately, clinics were only included when the Practice Management System (PMS) appeared to be able to provide information on antimicrobial prescription data specified for companion animals on a monthly basis. Clinics treating companion animals only and mixed clinics (i.e. clinics treating companion animals and non-companion animals, but with separated companion and non-companion animal prescription data) were included.

Clinics were offered a financial compensation, which was based upon estimated time investment per clinic and a standard hourly tariff for veterinarians. Educational training included in the ASP was accredited as professional continuing education for participating veterinarians.

The study was exempt from ethical approval as no animal experiments were involved. Participating veterinarians remained fully autonomous in their daily practice. Before enrolment, all clinics received written and oral information on the purpose of the study. Every clinic signed an informed consent to confirm their commitment to participate and to give permission for the use of their patient data for research purposes after anonymisation.

Applied intervention approach

A stewardship programme to optimise AMU was developed based upon previous qualitative research [19] and field experiences from co-authors involved in human medicine. The objectives of the ASP were to increase awareness on AMU, to decrease total AMU whenever possible and to shift AMU towards 1st choice agents, which is according to current guidelines on AMU. Cues from the RESET Model to change human behaviour were used; Rules & regulations, Education & information, Social pressure, Economics, and Tools [20,21]. A Support-Team (S-Team) was assembled, in the analogy of the human Antibiotic Stewardship-Teams (A-team) [22,23]. The S-team included a veterinary microbiologist, a veterinary specialist in internal medicine of companion animals, a veterinary pharmacologist, a hospital pharmacist and the project leader. The S-Team members were involved in the different elements of the ASP (Table 1).

Table 1

Separate intervention elements as offered during the ASP, including when they were offered, who were involved and the estimated time investment for participants.

Intervention element	When	Who were involved	Estimated time investment
1) Filling in (preferably) 100 patient evaluation forms per clinic; to reflect on own AM prescribing behaviour	At the start of the intervention period & at the end	Veterinarians	2–5 minutes per evaluation form
2) Post educational training 1; on AMR, international and national regulations, and guidelines on responsible AMU	Month 1	Veterinarians and 2 S-Team members	2.5 hours
3) Exercise to write down own AM prescribing behaviour; to compare it with current guidelines and to discuss it with colleagues	Between post educational training 1 & 2	Veterinarians within the same clinic	2 hours
4) Post educational training 2; on behavioural change and communication skills towards companion animal owners	Month 4	Veterinarians, veterinary nurses, 2 S-Team members and 1 communication trainer	2.5 hours
5) Commitment form; to sign within the clinic, committing to use AMs responsibly	After post educational training 2	Veterinarians and veterinary nurses	0.5 hour
6) Benchmarking of quantitative AMU data	During post educational training 1 and the feedback meeting	Veterinarians and S-Team members
7) Information leaflet for companion animal owners on responsible AMU and AMR	During participation in the intervention programme	Veterinarians and veterinary nurses
8) Asking questions to the S-team members, on AMU and AMR, via email or phone call	During participation in the intervention programme	Veterinarians and S-Team members
9) Feedback meeting; every clinic was visited once, clinic-based feedback was given on all gathered data on AMU (1, 3 and 6). Clinic specific AMU objectives were defined, questions were answered and topics on AMU and AMR were discussed	Month 8	Veterinarians and 2 S-Team members	2–3 hours

The Dutch classification [26] of veterinary AMU (Table 2), current Dutch guidelines (on otitis externa, urinary tract infections and skin infections) and formulary on veterinary AMU, and legislation on mandatory susceptibility testing for veterinary use of 3rd choice AMs were used as treatment standards during the ASP [13,24-26].

Table 2

Classification of veterinary AMU according to Dutch policy on veterinary AMU [26].

Classification	Reasoning	Main classes of AMs
1st choice	Empirical therapy; Do not select for (to current knowledge), nor are specifically meant for treatment of ESBL-producing micro-organisms.	Tetracyclines, nitroimidazoles, narrow-spectrum penicillins, trimethoprim, sulfonamides, lincosamides and phenicols.
2nd choice	All AMs not classified as 1st or 3rd choice AMs; Use of these AMs might select for ESBL-producing bacteria or is specifically indicated in case of an ESBL-infection.	Aminopenicillins (with/without beta-lactamase inhibitors), 1st and 2nd generation cephalosporins, aminoglycosides and colistin.
3rd choice	A selection of Highest Priority Critically Important AMs for human medicine according to WHO; By Dutch law restricted to use only in individual animals and after culture and susceptibility testing.	Fluoroquinolones, 3rd and 4th generation cephalosporins.

Data collection and management

Participating clinics supplied clinic population data and monthly antimicrobial veterinary medicinal product (AVMP) prescription data. Information on the composition of the clinic’s animal population (represented by the number of dogs, cats and rabbits attending the clinic at least once in a specified 3-year period) and monthly AM prescription data were retrieved retrospectively from the PMS, once before participation in the ASP and once after participation in the ASP.

Outcome measures

The primary outcome measure was total AMU. AMU was further classified into 1st, 2nd and 3rd choice AMU (Table 2).

Systemic AMU was quantified as described and discussed in detail in previous study [16] and is comparable with the Defined Daily Dose Animal (DDDAVET), a measure suggested by the European Surveillance of Veterinary Antimicrobial Consumption group (ESVAC) [27,28]. In summary, a DDDACLINIC of 0.25 per month means that the average dog, cat and rabbit in the clinic was treated with antimicrobials for a 0.25 day per month. Per clinic, total DDDACLINIC was calculated per month and specified with 1st, 2nd and 3rd choice AMU. In the present study, only systemic (i.e. oral or parenteral) AMU was described. AMs applied topically were excluded from analyses.

Mean absolute AMU numbers are presented for 12–24 months and 0–12 months prior to the start of the intervention period and for a period of 12 months considered as the actual intervention period, taking one month transition time into account.

Statistical analysis

A mixed effect time series model was used to describe monthly AMU from 12 months before until 12 months after the introduction of the ASP, that allowed for a linear trend over time, while seasonal patterns were modelled using Fourier (sine- and cosine-) terms. AMU appeared to follow an approximate log-normal distribution and therefore log-transformed AMU-data were used as the dependent variable. As a result, presented models estimate geometric mean (GM) AMU. Geometric mean ratios (GMRs; the ratio of two GMs) are used to quantify effects (e.g., the ratio of the GM during the intervention period to that before the intervention period).

The effect of the intervention was modelled using a step function and by modelling a change in the (linear) time trend. For each clinic, a dummy variable was included to indicate the month the ASP was introduced, because AMU in that month could not be unambiguously assigned to either the pre- or post-intervention period (transition period).

Heterogeneity in baseline AMU, time trends, seasonal patterns, and intervention effects across different clinics were modeled using (correlated) random effects. Short-term time series dynamics were accounted for by an auto-regressive (AR1) structure and the residual variance was allowed to be different for each clinic.

The estimated average intervention effects (i.e. the stepwise change and change in time trend) across clinics are reported. The model was used to evaluate the overall effect of the ASP for total, 1st, 2nd, and 3rd choice AMU separately. Effects are expressed as GMRs and (alternatively) as proportional decreases in use. PWALD values are used to indicate whether the separate coefficients are significantly different from 0, PF values are used to indicate the significance of the overall intervention effect.

SAS (SAS 9.4, SAS Institute, Inc. Cary, NC, USA) was used to organise the data and the nlme package (version 3.1) in R (version 3.5) was used to perform the statistical analyses.

Results

In total, 54 clinics were contacted to participate. Six of these clinics were not willing to participate and four clinics were excluded, because their PMS appeared not suitable to provide monthly prescription data. Finally, 44 clinics were included in the study.

Table 3 provides a summary of characteristics of participating clinics. All clinics provided AMU data prior to the introduction of the stewardship programme for a minimum of 25 months, except for one clinic, that provided data for only 13 months prior to the introduction of the ASP.

Table 3

Mean (range) or distribution of characteristics of 44 clinics participating in the ASP.

Characteristic (number of clinics = 44)	Mean (range)
Number of dogs	2151 (14–5353)
Number of cats	1910 (350–5113)
Number of rabbits	271 (0–797)
Number of veterinarians treating companion animals	2.7 (1–8)
Mean work experience per clinic (years)	16.2 (5.8–34)
Characteristic (number of clinics = 44)	Distribution
Companion animals only versus mixed-animal clinics	40 / 4
Urban, rural or urban-rural	29 / 14 / 1

Data of 41 clinics were included in the data analysis. Three clinics were excluded from data analysis. One of these clinics was lost to follow-up (i.e. no response was received when (repeatedly) trying to retrieve the AM prescription data from the PMS after participation in the ASP) and two clinics had substantial changes in their clinic’s animal composition (i.e. one clinic closed and one clinic opened an extra location with the same PMS making AMU calculations unreliable).

Outcomes

Mean, absolute AMU (total, 1st, 2nd and 3rd choice AMU)

Mean total AMU was 0.134 and 0.132 DDDA/month, respectively, in the two years prior to implementation of the ASP and decreased to 0.114 DDDA/month during the period considered as the intervention period (Table 4). Similar decreasing trends were seen for 3rd choice AMU (i.e. fluoroquinolones and 3rd generation cephalosporins) and 2nd choice AMU (i.e. mainly aminopenicillins, with and without clavulanic acid). AMU shifted towards more 1st choice AMU.

Table 4

Mean total, 1st, 2nd and 3rd choice AMU (in numbers of DDDA/month and percentage of total AMU) in participating clinics, before and during participation in the antimicrobial stewardship programme (ASP).

Classification of antimicrobials1	Pre-ASP period(12–24 months)	Pre-ASP period(0–12 months)	During participation in the ASP(2–13 months)
First choice (% of total)	0.059 (44.1%)	0.060 (45.5%)	0.066 (57.8%)
Second choice (% of total)	0.064 (47.6%)	0.063 (48.0%)	0.045 (39.2%)
Third choice (% of total)	0.011 (8.3%)	0.009 (6.5%)	0.003 (3.0%)
Total DDDA per month (SD)	0.134	0.132	0.114

1 = according to Dutch policy on veterinary AMU (Table 2)

Intervention effect

As a result of participation in the ASP, a stepwise decrease was estimated for total, 1st and 2nd choice AMU of 15% (95% CI: 7%-22%; p<0.01), 15% (95% CI: 5%-24%; p<0.01) and 26% (95% CI: 17%-34%; p<0.01) respectively. No statistically significant effect was estimated for 3rd choice AMU. The change in (linear) time trend was statistically significant for total AMU only with an additional 16% decrease over the year (95% CI: 4%-26%; p = 0.01) (Table 5).

Table 5

Stepwise change and change in (linear) trend of total, 1st, 2nd, and 3rd choice AMU.

Classification of antimicrobials1		GMR (95% CI)	% Decrease	PWALD	PF
First choice	Stepwise change in use	0.85 (0.76–0.95)	15% (5% to 24%)	<0.01	<0.01
	Change in (linear) trend (/year)	0.92 (0.74–1.13)	8% (-13% to 26%)	0.41
Second choice	Stepwise change in use	0.74 (0.66–0.83)	26% (17% to 34%)	<0.01	0.01
	Change in (linear) trend (/year)	0.85 (0.69–1.04)	15% (-4% to 31%)	0.12
Third choice	Stepwise change in use	0.94 (0.72–1.23)	6% (-23% to 28%)	0.66	0.62
	Change in (linear) trend (/year)	0.78 (0.46–1.32)	22% (-32% to 54%)	0.35
Total	Stepwise change in use	0.85 (0.78–0.93)	15% (7% to 22%)	<0.01	<0.01
	Change in (linear) trend (/year)	0.84 (0.74–0.96)	16% (4% to 26%)	0.01

Reported effects are averaged estimates of 41 participating clinics, from a random effects model that includes a (linear) time trend and seasonal effects, and allows for heterogeneity of effects between clinics and residual auto-correlation. Effects are expressed as GMRs and (alternatively) as proportional decreases in use.

1 = according to Dutch policy on veterinary AMU (Table 2)

As absolute figures for 1st choice AMU were increasing (not visible from Fig 2A–2D, because the trend before the ASP was set at 100%), the net effect of the stepwise decrease in 1st choice AMU is a smaller increase in use than was expected based upon the pre-intervention time trend for 1st choice AMU.

Fig 2

Average and clinic-specific effects of the ASP on total, 1st, 2nd and 3rd choice AMU.

Combined effect of participation in the ASP (stepwise change & change in time trend) are shown for the average effect (black) and for each individual clinic (grey) after standardisation to the estimated AMU before the intervention period (as 100%).

Although AMU decreased in most clinics, there were considerable differences in estimated intervention effects between clinics (Fig 2A–2D).

Discussion

A strong and statistically significant decrease in total, 1st and 2nd choice AMU was observed in a sample of Dutch companion animal clinics, with a shift towards use of 1st choice antimicrobials, that was attributed to participation in an antimicrobial stewardship programme (ASP). The change in total AMU became more prominent over time after introduction of the ASP.

The results of the statistical model indicate that 1st choice AMU decreased. However, absolute 1st choice AMU increased during the intervention period. Therefore, after introduction of the ASP, the net effect was a less pronounced increase in use of 1st choice AMs than was expected. The statistical model used to estimate the intervention effect, assumed a linear, random time trend per clinic and a stepwise reduction in AMU after adjustment for seasonal effects. The stepwise effect was observed in most clinics. No statistically significant effect on 3rd choice AMU could be attributed to participation in the ASP. This is likely explained by the fact that 3rd choice AMU was already reduced to a low level (0.009 DDDA/month, 0–12 months before implementation of the ASP) in the years preceding the ASP. Therefore, a further decrease as result of the ASP is difficult to demonstrate.

The goal of the ASP was to increase awareness on AMU, to decrease total AMU whenever possible and to shift AMU towards 1st choice AMs, according to Dutch guidelines on veterinary AMU [24,26]. The observed changes in the clinics participating in the ASP are in line with the goal of the ASP and the Dutch guidelines on veterinary AMU, and are therefore considered relevant.

A strength of the design of the present study is that repeated monthly measurements per clinic were involved, which allowed to control intervention effects for baseline levels and ongoing time trends. By starting the ASP at different timepoints for the four different clusters of clinics, the probability that the overall effect was influenced by external events was minimised (e.g., increased attention on responsible AMU in general) [6].

In general, measures to evaluate the effect of an ASP can be divided into four main categories: patient outcomes, unintended consequences of AMU (e.g., adverse effects and emergence of AMR), AMU and costs, and process measures [29]. As a possible limitation of present study, it could be argued that overall AMU is a non-specific measure without information on appropriateness of AM therapy or patient outcomes, as is the case for looking at 1st, 2nd and 3rd choice AMU [6,29-31]. Moreover and more important, an increase in quality of AMU can be reached without a reduction in AMU (or even with an increase in AMU), e.g., by using more 1st choice AMs instead of 2nd or 3rd choice AMs, or by using better dosing [6,32,33]. On the other hand, as any use of AMs selects for AMR, any reduction of AMU that can be achieved by improving adherence to current guidelines (by definition appropriate AMU) is an advantage, as is the case for using 1st instead of 2nd or 3rd choice AMs. The persistence of the effect during the follow-up period of 12 months (especially of total AMU with a significant change in linear time trend) suggests sustainability of the changes in AMU. However, repeated AMU-measurements in the nearby future are needed to evaluate the sustainability over a longer period of time.

A second limitation is the fact that participating clinics were contacted approximately 2–3 months before actual start of the ASP. This could have led to a change in AM prescribing behaviour already, because clinics knew their AM prescribing behaviour would be monitored. These 2–3 months are part of the baseline measurement period. As a result, the intervention/ASP effect could have been slightly diminished [6,34]. Another potential weakness of the stepped-wedge design is contamination of the interventions [6]. Information, insights or effects from clinics already having started the ASP could have influenced clinics still in the baseline period. Because participating clinics were clustered based on their geographic location, this effect was expected to be minimal, but could not be excluded.

The representativeness of the participating clinics for the whole country might be questioned. These 44 clinics were not randomly selected, but selection was based upon willingness to participate. It is possible that participating clinics already had a more responsible attitude towards AMU and had more motivation to change their AM prescribing behaviour compared to other not-participating clinics. On the other hand, results of the present study might also be regarded as a proof of principle. If even in clinics that already had an interest in responsible AMU, optimisation of AMU could be attained, clinics with less interest in responsible AMU might be able to change even more. However, and irrefutably, it will be harder to change behaviour of veterinarians who do not believe that responsible AMU is a desirable or necessary behaviour [19,20,35].

Antimicrobial prescribing behaviour is influenced by many factors. Multifaced interventions, attuned to the specific setting and influencing factors of AMU are advised to optimise AM prescribing behaviour [7,8,18,19,36-38]. The present ASP was based upon a previous qualitative study and the RESET model, containing the most important cues to change human behaviour [19,20]. Only ‘Economics’, covering profits and costs, bonuses and penalties, as a factor influencing prescribing behaviour was not addressed directly in the ASP. However, the importance of economics was discussed (e.g., the difference between earning money because of prescribing AMs versus performing further diagnostics). Besides, clinics were aware of possible inspections by the Dutch Food and Consumer Product Safety Authority (NVWA) of the Dutch Government, possibly leading to financial penalties in case of prescribing 3rd choice AMs without culture and susceptibility testing.

The present study showed that the developed ASP was effective in reducing and refining AMU in the participating clinics. An evaluation survey among participants and a stakeholders consultation will elucidate which intervention elements are the most promising elements for future implementation in other clinics or countries [39].

Conclusions

Participation in a multifaceted antimicrobial stewardship programme to optimise AMU in companion clinics, showed a positive effect on AMU in Dutch companion animal clinics. For future and feasible, large scale implementation, the most effective and efficient parts of the ASP need to be selected.

8 Aug 2019

PONE-D-19-19385

Implementation and evaluation of an Antimicrobial Stewardship Programme in companion animal clinics: a stepped-wedge design intervention study

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Reviewer #1: This study assesses the impact of an antimicrobial stewardship program (ASP) on prescribing practices in 41 Dutch companion animal practices. ASP has been relatively neglected in companion animals globally compared to the focus on food animals, but is an important topic because people interact more closely with pet than with food animals (or their products). As expected from this group, the study was very well designed, in this case using a stepped-wedge intervention study implementing an ASP which was specifically developed for this study, and used practice management software to obtain the monthly data on antimicrobial use (AMU) needed (cats, dogs, rabbits) 2-years prior and during the 12-month ASP study period. The ASP program used a “RESET” model to guide changes in prescribing behaviour. The study showed a significant reduction in AMU and a significant shift to use of AMs of lower importance (except for third choice which were already low). There were considerable clinic differences. The discussion is excellent, self-critical of the limitations but with excellent arguments for the validity of the findings. The discussion is an excellent guide to others in other countries contemplating this type of needed action. This article leads the way in an on objective science-based intervention and analysis. The writing, tables, and figures are uniformly excellent. This is a very important paper in its field.

Line 292: net spelling

302: The goal of ….

Reviewer #2: The manuscript could be a good addition to scientific literature. It is generally well written except for a few issues that can be fixed. It might be beneficial to have an English language specialist read through (proof read). We do this quite often (have an English language specialist proof read our manuscripts) for our manuscripts. I am happy to review it again after the authors have addressed the issues that I raise.

Please see my comments below:

Abstract

Please consider indicating the time when the intervention study was conducted in the abstract.

Line 42-43: Please consider rephrasing...when you say to to perform and evaluate the effectiveness of an ASP ...perhaps you meant to say to implement and evaluate.... This also applies to lines 101-103.

Line 47: Should begin with...The objectives

Introduction

Line 71: Please mention some of the numerous elements of improved AMU.

Lines 74-76: Please consider rewriting this statement. Looks like a comma is missing before the word "between" in line 74.

Lines 76-77: Consider rephrasing.

Line 79: It would have been nice if reference 13 was in English. Can you try to translate reference 13 to English? Is there an English version? Having a link to an English version of reference 13 would benefit a reader who has no knowledge of Dutch. Just a thought. Please, provide a URL to reference 13.

Lines 86-87: This statement is either not well written or incomplete. For example "when comparing 2012-2014" is very confusing. Did you mean when comparing 2012 to 2014? Please consider rephrasing.

Line 100: Please consider adding "the" before "present".

Method

Line 104: Should it not be materials and methods? I believe you used some materials and several methods. Please consider replacing "Method" with "Materials and methods".

Line 118: Did you mean first cluster clinics and not "first clinics"? It is a bit confusing.

Line 120: Consider adding "The" before "clinics".

Line 129: Please consider replacing "from an earlier conducted study" with from a previous study. It might add value to also mention where this previous study was conducted.

Line 134: Please consider adding the word "The" before "clinics".

Line 141: Consider removing the word so-called (and throughout the manuscript). Depending on the reader, the word so-called may have a negative connotation. It may be interpreted that you think the use of such words are inappropriate. Please, check all the different dictionary meanings of the word so-called. You may choose to use "Mixed animal practices", if you believe "mixed clinics" is not appropriate.

Line 158: Please add "The" before "objectives".

Line 162: Delete "so-called".

Lines 164-167: I am wondering why there was no veterinary epidemiologist and/or infection prevention/control specialist in the S-team. I strongly believe that infection prevention/control is a very important element of an ASP. Any clarifications on this?

Line 168: Consider adding the word The before Dutch.

Line 171: I accessed references 25 and 26, but they are in Dutch. I wish there were English versions too.

Line 186: The primary outcome measure was total AMU. I look forward to the time when we will start to also consider metrics such as antibiotic associated length of stay in vet clinics,clinical response,AMR associated mortalities etc. These metrics have been suggested in human medicine (please read https://academic.oup.com/cid/article/59/suppl_3/S112/318184).

Line 187: Please consider moving reference 26 to line 168. consider inserting it after classification and before of.

Line 195: Presented for 24-12 months and 12-0 months (instead of 12-24 months and 0-12 months) may be confusing to an ordinary reader. Any reasons for this?

Lines 195-197: Please consider rephrasing the statement in lines 195-197 for clarity. In line 196, please insert the after to and before start.

Lines 198-199: This is really not a paragraph.

Line 201: Please, consider moving table 2 to just after table 1 and before data collection and management.

Results.

Lines 239-242: Did you mean to say that all clinics provided AMU data prior to the introduction of the ASP for a minimum of 24 months except for one clinic? Using the word "could" makes it sound like there is some doubt.. Please consider deleting the word could and rephrasing the statement in lines 239-242. Could in this context is used to express possibility (which could be uncertain possibility).

Line 244: Please, try to explain to the reader how the clinic got lost to follow-up. I believe there is a reasonable explanation for this loss to follow-up.

Lines 261-263: Please try rewriting this table heading for clarity. Make it simple for even an eighth grader.

Line 276: Did you mean Figures 2A-D? And not Figure 2. You have figures 2A-D, I didn't see a specific figure labeled Figure 2. Please clarify.

Discussion

Line 287: If you are sure of your findings, then you should unequivocally state that you attribute the observed shift to participation in the ASP.

Line 292: Replace nett with net. Also consider replacing effect is with effect was.

Line 296: Consider replacing "No statistical" with No statistically

Lines 297-301: Very long statement. Consider rephrasing.

Lines 300-301: when you say...due to lack of statistical power, are you not negating your power calculation in lines 125-129? Please clarify or rephrase.

Line 302: Insert "The" before "Goal".

Lines 304-305: Please check the statement beginning with "The observed..." for grammar/syntax.

Lines 313-325: This is a good discussion. This paper "" ext-link-type="uri" xlink:type="simple">https://academic.oup.com/cid/article/59/suppl_3/S112/318184" may also be useful for your discussion.

Line 344: Please consider replacing irrefutable with irrefutably.

Line 348: Replace AM with Antimicrobial.

Line 353: Please add "a" after as and before factor.

Lines 360-365: I wonder how useful this paragraph is to the paper. Lines 362-364 is confusing. Please consider rewriting in a more clear language.

Lines 366-370: In my view, this discussion points are not necessary for this manuscript.

Conclusion

The presented conclusion appears too general.

Lines 375-376: From your study, please mention the most effective and efficient parts of the ASP that need to be selected.

Reviewer #3: This is an excellent paper and well worthy of publication. The statistics appear to be rigorously performed and the sample size and intervention achieved mean the results have real impact for the veterinary community.

Line 79-80. This sentence needs rewording to improve clarity. Does the Dutch vet association promote the use of guidelines or require them???

Line 88-92: This needs a reference.

**********

6. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files.

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Reviewer #1: No

Reviewer #2: No

Reviewer #3: No

[NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files to be viewed.]

While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/. PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email us at figures@plos.org. Please note that Supporting Information files do not need this step.

Submitted filename: PLoS One ASP.docx

Click here for additional data file.

8 Oct 2019

This information is also included in the uploaded document named "Response to reviewers":

Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: This study assesses the impact of an antimicrobial stewardship program (ASP) on prescribing practices in 41 Dutch companion animal practices. ASP has been relatively neglected in companion animals globally compared to the focus on food animals, but is an important topic because people interact more closely with pet than with food animals (or their products). As expected from this group, the study was very well designed, in this case using a stepped-wedge intervention study implementing an ASP which was specifically developed for this study, and used practice management software to obtain the monthly data on antimicrobial use (AMU) needed (cats, dogs, rabbits) 2-years prior and during the 12-month ASP study period. The ASP program used a “RESET” model to guide changes in prescribing behaviour. The study showed a significant reduction in AMU and a significant shift to use of AMs of lower importance (except for third choice which were already low). There were considerable clinic differences. The discussion is excellent, self-critical of the limitations but with excellent arguments for the validity of the findings. The discussion is an excellent guide to others in other countries contemplating this type of needed action. This article leads the way in an on objective science-based intervention and analysis. The writing, tables, and figures are uniformly excellent. This is a very important paper in its field.

Line 292: net spelling

302: The goal of ….

Dear Reviewer 1, thank you very much for critically revising our manuscript and your very complimentary words. We changed the word “nett” into “net” (Line 303) and “Goal of the ASP” was changed into “The Goal of the ASP” (Line 312).

Reviewer #2: The manuscript could be a good addition to scientific literature. It is generally well written except for a few issues that can be fixed. It might be beneficial to have an English language specialist read through (proof read). We do this quite often (have an English language specialist proof read our manuscripts) for our manuscripts. I am happy to review it again after the authors have addressed the issues that I raise.

Dear Reviewer 2, thank you very much for critically revising our manuscript, your kind words and the given opportunity to improve our manuscript. We will address all the issues you raise separately below.

Please see my comments below:

Abstract

Please consider indicating the time when the intervention study was conducted in the abstract.

The text “which was performed from March 2016 until March 2018” is added now in Line 37.

Line 42-43: Please consider rephrasing...when you say to to perform and evaluate the effectiveness of an ASP ...perhaps you meant to say to implement and evaluate.... This also applies to lines 101-103.

“Perform” was replaced by “implement” in both sentences, Line 34 and 95.

Line 47: Should begin with...The objectives

“The” is added in Line 39.

Introduction

Line 71: Please mention some of the numerous elements of improved AMU.

“(e.g., increasing awareness of (inter)national practice guidelines, use of diagnostic microbiology and use of alternatives to AMs)” was added to mention some examples of the numerous elements of improved AMU, Line 65-66.

Lines 74-76: Please consider rewriting this statement. Looks like a comma is missing before the word "between" in line 74.

This sentence was rephrased: “In Dutch food producing animals, a combination of compulsory and voluntary actions resulted in a 64% reduction in AMU (between 2008 and 2017). A decrease in resistance rates was observed as well.” Line 68-70.

Lines 76-77: Consider rephrasing.

This sentence was rephrased: “Just since the end of 2011 onwards, more attention is being paid to AMU in companion animals”, Line 70-71.

Line 79: It would have been nice if reference 13 was in English. Can you try to translate reference 13 to English? Is there an English version? Having a link to an English version of reference 13 would benefit a reader who has no knowledge of Dutch. Just a thought. Please, provide a URL to reference 13.

As it concerns Dutch law, the reference is in Dutch and there is no English version of it. We added an URL to the Dutch website and we translated the title into English (“Regulation of the State Secretary of Economic Affairs”) in the reference list, but unfortunately there is no English version.

Lines 86-87: This statement is either not well written or incomplete. For example "when comparing 2012-2014" is very confusing. Did you mean when comparing 2012 to 2014? Please consider rephrasing.

This sentence was rephrased: “During the past years, AMU in Dutch companion animal clinics has been decreasing (with 19% when comparing 2012 to 2014)”, Line 80-81.

Line 100: Please consider adding "the" before "present".

“The” was added in Line 94.

Method

Line 104: Should it not be materials and methods? I believe you used some materials and several methods. Please consider replacing "Method" with "Materials and methods".

Thank you, you are completely right. The heading is now “Materials and methods”.

Line 118: Did you mean first cluster clinics and not "first clinics"? It is a bit confusing.

First clinics was changed into “The first cluster of clinics was contacted”, Line 112.

Line 120: Consider adding "The" before "clinics".

“The” was added in Line 114.

Line 129: Please consider replacing "from an earlier conducted study" with from a previous study. It might add value to also mention where this previous study was conducted.

The sentence was changed as you suggested: “Calculations were based on AMU data at clinic level from a previous study conducted in 68 Dutch companion animal clinics”, Line 127-128.

Line 134: Please consider adding the word "The" before "clinics".

“The” was added before clinics, Line 132.

Line 141: Consider removing the word so-called (and throughout the manuscript). Depending on the reader, the word so-called may have a negative connotation. It may be interpreted that you think the use of such words are inappropriate. Please, check all the different dictionary meanings of the word so-called. You may choose to use "Mixed animal practices", if you believe "mixed clinics" is not appropriate.

Thank you very much for this comment and your explanation. “So-called” was removed in Line 139 and in Line 160.

Line 158: Please add "The" before "objectives".

“The” was added, Line 156.

Line 162: Delete "so-called".

“So-called” was deleted, in Line 160.

Lines 164-167: I am wondering why there was no veterinary epidemiologist and/or infection prevention/control specialist in the S-team. I strongly believe that infection prevention/control is a very important element of an ASP. Any clarifications on this?

Thank you very much for this comment. We fully agree that infection prevention/control is very important in all strategies to preserve AMs and in A-teams in human hospitals an infection prevention/control specialist is involved. In the ASAP-project group an epidemiologist (also in author list) and an infection prevention/control specialist were involved. But indeed, not directly in the S-team. One of the explanations hereof has to do with logistic issues. Another explanation is that our ASP was primarily focused on prudent use of AMs (right choice, dose and length) and less on infection prevention. Line 168: Consider adding the word The before Dutch.

“The” was added, Line 166.

Line 171: I accessed references 25 and 26, but they are in Dutch. I wish there were English versions too.

Unfortunately, only Dutch versions of these documents exist, no English translations are available. As the Dutch classification of AMs (reference 26) is crucial for the interpretation of our data/results, this is explained in Table 2.

Line 186: The primary outcome measure was total AMU. I look forward to the time when we will start to also consider metrics such as antibiotic associated length of stay in vet clinics,clinical response,AMR associated mortalities etc. These metrics have been suggested in human medicine (please read https://academic.oup.com/cid/article/59/suppl_3/S112/318184).

Thank you for this comment. We totally agree and we therefore mention this in the discussion.

Line 187: Please consider moving reference 26 to line 168. consider inserting it after classification and before of.

Reference 26 is moved to Line 166 and inserted before “of”.

Line 195: Presented for 24-12 months and 12-0 months (instead of 12-24 months and 0-12 months) may be confusing to an ordinary reader. Any reasons for this?

We understand the potential confusion of the used notation. We changed it into 12-24 and 0-12, both in Line 200 and Table 4.

Lines 195-197: Please consider rephrasing the statement in lines 195-197 for clarity. In line 196, please insert the after to and before start.

As you suggested, the statement was rephrased and in Line 201 “the” was added.

Lines 198-199: This is really not a paragraph.

We now placed this sentence in the previous paragraph, Line 197-198.

Line 201: Please, consider moving table 2 to just after table 1 and before data collection and management.

Table 2 was moved as you suggested.

Results.

Lines 239-242: Did you mean to say that all clinics provided AMU data prior to the introduction of the ASP for a minimum of 24 months except for one clinic? Using the word "could" makes it sound like there is some doubt.. Please consider deleting the word could and rephrasing the statement in lines 239-242. Could in this context is used to express possibility (which could be uncertain possibility).

Thank you, it was indeed as you suggested, all clinics provided “before” data of at least 24 months, except for one clinic. Therefore the sentence was changed: “All clinics provided AMU data prior to the introduction of the stewardship programme for a minimum of 25 months, except for one clinic, that provided data for only 13 months prior to the introduction of the ASP”, Line 239-242.

Line 244: Please, try to explain to the reader how the clinic got lost to follow-up. I believe there is a reasonable explanation for this loss to follow-up.

This clinic was lost to follow-up, because the clinic did not respond anymore to repeated phone calls and e-mails, when trying to retrieve their AM prescription data after participation in the ASP (which they did fully participate in). Therefore, this line was added: “One of these clinics was lost to follow-up (i.e. no response was received when (repeatedly) trying to retrieve the AM prescription data from the PMS after participation in the ASP) ”, Line 244-246.

Lines 261-263: Please try rewriting this table heading for clarity. Make it simple for even an eighth grader.

The table heading was rewritten: “Mean total, 1st, 2nd and 3rd choice AMU (in numbers of DDDA/month and percentage of total AMU) in participating clinics, before and during participation in the antimicrobial stewardship programme (ASP).

Line 276: Did you mean Figures 2A-D? And not Figure 2. You have figures 2A-D, I didn't see a specific figure labeled Figure 2. Please clarify.

You are right, I indeed mean Fig. 2A-D. This was changed.

Discussion

Line 287: If you are sure of your findings, then you should unequivocally state that you attribute the observed shift to participation in the ASP.

As we are sure of our findings, we rephrased this sentence: “that was attributed to participation in an antimicrobial stewardship programme” (Line 298-299).

Line 292: Replace nett with net. Also consider replacing effect is with effect was.

Both changes were made: “the net effect was a less pronounced increase”, Line 303.

Line 296: Consider replacing "No statistical" with No statistically

“No statistical” was replaced with “No statistically”, Line 307.

Lines 297-301: Very long statement. Consider rephrasing.

Lines 300-301: when you say...due to lack of statistical power, are you not negating your power calculation in lines 125-129? Please clarify or rephrase.

This sentence was rephrased: “This is likely explained by the fact that 3rd choice AMU was already reduced to a low level (0.009 DDDA/month, 0-12 months before implementation of the ASP) in the years preceding the ASP. Therefore, a further decrease as result of the ASP is difficult to demonstrate.

Line 302: Insert "The" before "Goal".

“The” was inserted, in Line 312.

Lines 304-305: Please check the statement beginning with "The observed..." for grammar/syntax.

This sentence was changed: “The observed changes in the clinics participating in the ASP are in line with the goal of the ASP and the Dutch guidelines on veterinary AMU, and are therefore considered relevant”, Line 314-316.

Lines 313-325: This is a good discussion. This paper "https://academic.oup.com/cid/article/59/suppl_3/S112/318184" may also be useful for your discussion.

Thank you for this compliment and the reference. The suggested paper is used in the discussion now, Line 324-326. “In general, measures to evaluate the effect of an ASP can be divided into four main categories: patient outcomes, unintended consequences of AMU (e.g., adverse effects and emergence of AMR), AMU and costs, and process measures [29]”. And it was added as reference in Line 329.

Line 344: Please consider replacing irrefutable with irrefutably.

“Irrefutable” is replaced with “irrefutably”, Line 358.

Line 348: Replace AM with Antimicrobial.

AM was replaced with “antimicrobial”, Line 362.

Line 353: Please add "a" after as and before factor.

In Line 367 “a” was added.

Lines 360-365: I wonder how useful this paragraph is to the paper. Lines 362-364 is confusing. Please consider rewriting in a more clear language.

We rewrote his paragraph. Until now we only evaluated the effectiveness of the ASP on AMU, we did not evaluate the opinions and experiences of the participants yet. This is necessary to answer which intervention element(s) worked best. “The present study showed that the developed ASP was effective in reducing and refining AMU in the participating clinics. An evaluation survey among participants and a stakeholders consultation will elucidate which intervention elements are the most promising elements for future implementation in other clinics or countries [39]” (Line 374-377).

Lines 366-370: In my view, this discussion points are not necessary for this manuscript.

We agree with your comment and therefore omitted this discussion point.

Conclusion

The presented conclusion appears too general.

Lines 375-376: From your study, please mention the most effective and efficient parts of the ASP that need to be selected.

Until now, it was not possible yet to mention the most effective and efficient parts of the ASP, this should be based upon an evaluation with the participants. Therefore, this will soon be our next step to enable future and feasible, large scale implementation.

Reviewer #3: This is an excellent paper and well worthy of publication. The statistics appear to be rigorously performed and the sample size and intervention achieved mean the results have real impact for the veterinary community.

Dear Reviewer, thank you very much for reviewing our manuscript and for your kind words.

Line 79-80. This sentence needs rewording to improve clarity. Does the Dutch vet association promote the use of guidelines or require them???

This sentences was clarified as you suggested: “The Dutch Veterinary Association “promotes” the use of guidelines on AMU as well”, Line 73-74.

Line 88-92: This needs a reference.

A reference is now added in Line 86.

Submitted filename: PLoS One - response to reviewersv3.docx

Click here for additional data file.

30 Oct 2019

Implementation and evaluation of an Antimicrobial Stewardship Programme in companion animal clinics: a stepped-wedge design intervention study

PONE-D-19-19385R1

Dear Dr. Broens

We are pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it complies with all outstanding technical requirements.

Within one week, you will receive an e-mail containing information on the amendments required prior to publication. When all required modifications have been addressed, you will receive a formal acceptance letter and your manuscript will proceed to our production department and be scheduled for publication.

Shortly after the formal acceptance letter is sent, an invoice for payment will follow. To ensure an efficient production and billing process, please log into Editorial Manager at https://www.editorialmanager.com/pone/, click the "Update My Information" link at the top of the page, and update your user information. If you have any billing related questions, please contact our Author Billing department directly at authorbilling@plos.org.

If your institution or institutions have a press office, please notify them about your upcoming paper to enable them to help maximize its impact. If they will be preparing press materials for this manuscript, you must inform our press team as soon as possible and no later than 48 hours after receiving the formal acceptance. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information, please contact onepress@plos.org.

With kind regards,

Simon Russell Clegg, PhD

Academic Editor

PLOS ONE

Additional Editor Comments (optional):

Many thanks for resubmitting your interesting manuscript to PLOS One, and for the time taken to produce a good response to reviewers

The manuscript was re-reviewed by the same reviewers as before, and I am pleased to say that they have recommended that the manuscript be accepted for publication

I wish you all the best for your future research

Many thanks

Simon

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation.

Reviewer #2: All comments have been addressed

Reviewer #3: All comments have been addressed

**********

2. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #2: Yes

Reviewer #3: Yes

**********

3. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #2: Yes

Reviewer #3: Yes

**********

4. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #2: No

Reviewer #3: No

**********

5. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #2: Yes

Reviewer #3: Yes

**********

6. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #2: (No Response)

Reviewer #3: (No Response)

**********

7. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy.

Reviewer #2: No

Reviewer #3: No

8 Nov 2019

PONE-D-19-19385R1

Implementation and evaluation of an Antimicrobial Stewardship Programme in companion animal clinics: a stepped-wedge design intervention study

Dear Dr. Broens:

I am pleased to inform you that your manuscript has been deemed suitable for publication in PLOS ONE. Congratulations! Your manuscript is now with our production department.

If your institution or institutions have a press office, please notify them about your upcoming paper at this point, to enable them to help maximize its impact. If they will be preparing press materials for this manuscript, please inform our press team within the next 48 hours. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information please contact onepress@plos.org.

For any other questions or concerns, please email plosone@plos.org.

Thank you for submitting your work to PLOS ONE.

With kind regards,

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on behalf of

Dr. Simon Russell Clegg

Academic Editor

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