Antimicrobial use and stewardship activities in Swiss long-term care facilities: data from a national point-prevalence survey

Abstract

Background

The first nation-wide point-prevalence survey (PPS) in Swiss long-term care facilities (LTCF) showed significant geographical differences in antimicrobial use. The aim of this study was to characterize these variations, identify associated factors, and assess antimicrobial stewardship (AMS) practices.

Methods

The PPS was performed in September 2024. A sample of Swiss LTCFs was randomly selected for representativeness according to language region and size. The PPS was also open to all interested Swiss LTCFs. Data were collected using the adapted Healthcare-Associated Infections in European Long-Term Care Facilities (HALT)-4 protocol. Data on antimicrobial use and AMS elements were stratified by language region. To identify factors independently associated with antimicrobial use, multivariable logistic regression was performed including resident- and institution-level variables.

Results

The sample included 7244 residents from 94 LTCFs (43 from German, 18 from French, and 33 from Italian language regions). Most common indications for antimicrobial treatment were urinary tract infections, respiratory tract infections and skin or soft tissue infections, across all language regions. Antimicrobial prophylaxis (32% 67/209) was more common in the French (41%, 26/64) compared to the Italian (29%, 24/82) and German language regions (27%, 17/63). Most commonly prescribed substances for prophylaxis were trimethoprim/sulfamethoxazole, nitrofurantoin and amoxicillin/clavulanic acid. Adoption of AMS elements was low and more common in the French and Italian language region. In multivariable analysis, residing in a LTCF from the French language region remained the strongest factor associated with antimicrobial use (adjusted odds ratio [aOR] 2.99, 95% CI 1.76–5.01). Further factors were recent hospitalisation or surgery (aOR 2.19, 95% CI 1.50–3.19), urinary catheter use (aOR 2.10, 95% CI 1.36–3.24) and use of proton pump inhibitor (aOR 1.49, 95% CI 1.11-2.00), but not the number of implemented AMS elements.

Conclusions

Antimicrobial use in Swiss LTCF is higher in the French compared to the Italian and the German language region, independent of other factors. These findings highlight the need for regional surveillance, AMS interventions tailored to local epidemiology, and assessment strategies for their implementation and effectiveness. The high proportion of prophylactic antimicrobials warrants further investigation to determine underlying causes and represents a target for AMS interventions.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13756-026-01749-0.

Background

The burden and relevance of antimicrobial resistance (AMR) in long-term care facilities (LTCF) are being increasingly recognized, with mounting evidence that this particular setting can act as a reservoir and catalysator for the spread of AMR [1–3]. Internationally, multiple point-prevalence surveys (PPS) have shown the frequent antimicrobial use in LTCF and also its considerable geographical variation, both in the proportion of antimicrobials prescribed for prophylaxis and in the indication for therapeutic use [1, 4]. In 2024, the first nation-wide PPS of Switzerland showed a prevalence of health-care associated infections (HAI) and antimicrobial use similar to the European average [5]. However, antimicrobial use varied significantly, with higher rates observed in the French and Italian language regions compared to the German language region. These geographical variations in antimicrobial use do not seem to be explainable by differences in HAI rates [5]. Within the European PPS, factors both at the institutional and resident level were associated with antimicrobial use and could account for part of the geographical variation [6].

Antimicrobial stewardship (AMS) programmes are widely implemented in the acute care setting, but data on their implementation in LTCF are limited and largely lacking in Switzerland.

In this study, we aimed to further elucidate the variation in antimicrobial use (both as therapy and prophylaxis) in LTCF across the three main Swiss language regions, to describe the adoption of AMS in Swiss LTCF, and to identify independent factors associated with antimicrobial use.

Methods

Setting and study design

There are around 1’500 LTCF in Switzerland, caring for 155’000 residents per year. All LTCF are listed in a national registry, around half (47%) are privately owned and the mean age at admission is 82 years. For the PPS, a representative sample of institutions was chosen across the country. Sampling was performed by stratified randomisation based on population size of each language region and on facility size (number of beds). Additionally, interested LTCF voluntarily participated in the survey. Details of the recruitment process are described elsewhere [5].

Data collection and definitions

Data collection took place between September 9th and September 27th, 2024 and was performed according to the Healthcare-Associated Infections in European Long-Term Care Facilities 4 (HALT-4) protocol [7]. The study period was deliberately set outside of the viral respiratory season as recommended by the protocol [7]. Data collection was performed by LTCF representatives (facility directors, senior nurses, infection and prevention control specialists or link nurses), who were trained on the ECDC HALT-4 protocol by the study team. A study manual and telephone support by the study team was provided throughout the PPS. Data collectors were instructed to complete data collection within one day, if possible, otherwise on more consecutive days in case of large institutions. Data were collected from chart reviews and entered either directly into a REDCap database or first in paper-based forms and afterwards into the REDCap database. Further details on data collection are provided elsewhere [5].

At the institutional level, data comprised general information such as type of facility, size, number of healthcare personnel, and language region. Language region was defined as follows: the French language region comprised the cantons of Fribourg, Genève, Jura, Neuchâtel, Valais and Vaud; the Italian language region comprised the canton of Ticino; the German language region comprised all other cantons. The presence of AMS structures and parameters was assessed according to the following ten key elements: AMS committee, regular teaching on rational antimicrobial use, written guidelines for antimicrobial use, surveillance on antimicrobial consumption by substance, diagnostic stewardship tools, local AMR data accessible for physicians, restriction on prescribing certain antimicrobial substances, pharmacist support for selection and prescription of reserve antimicrobials, therapeutic guidelines with antimicrobial lists, and reporting of antimicrobial use to prescribing physicians. Representatives of each LTCF were also asked by questionnaire about their perception of antimicrobial use and AMS by rating the importance of antimicrobial use in the LTCF-setting and indicating whether and which additional measures were needed to reduce antimicrobial use. At the resident level, data comprised demographic information, health characteristics, care dependency (a score ranging from 0, for less than 20 min of care per day, to 12, for more than 220 min of care per day), HAI and antimicrobial use. HAI were defined according to ECDC criteria, as per HALT-4 protocol. Only antimicrobials (antibacterials, antimycotics and antivirals) for systemic use were included.

Few adaptations were made to the HALT-4 protocol: a new variable corresponding to the sum of available AMS elements (ranging from 0 to 10); the proportion of auxiliary nurses as percentage of all nursing full-time equivalents per institution; and the use of proton pump inhibitors (PPI). Additionally, resident health characteristics were collected individually for all eligible residents and not only for those with reported HAI or antimicrobial use. Detailed questionnaires are available in supplementary material (see Supplementary File 1, Table S4 und S5).

Statistical analysis

Statistical analyses of the present study were conducted on the full sample to increase the robustness of the multivariable analysis, improve comparisons across language regions, and provide a larger dataset for the characterization of antimicrobial use and AMS adoption in the country. This approach is supported by the similarity of resident and institutional characteristics between the representative sample and the full sample, as described elsewhere [5]. Categorical variables were reported as numbers and percentages, continuous variables as median and ranges or interquartile ranges (IQR). Results were compared by language region using descriptive statistics. Reported 95% confidence intervals (CI) were calculated using the normal approximation method. Analysis of factors associated with antimicrobial use was performed using logistic regression and was reported as odds ratios (OR), adjusted odds ratios (aOR), and 95% CI. Only factors demonstrating statistical significance in the univariable analysis were included in the multivariable analysis. As a sensitivity analysis, we also fitted mixed-effects (random intercept) models accounting for institutional clustering, both for univariable and multivariable analysis. We used statistical software R, version 4.4.2, for all analyses. Statistical significance was considered for p-values < 0.05. The lme4 package, version 1.1–35.5, was used for mixed-effects models.

Results

Characteristics of residents and institutions

The sample included 94 institutions caring for 7244 residents. We included 43 (46%) institutions from the German, 18 (19%) from the French and 33 (35%) from the Italian language region. Institutional and resident characteristics of the three language regions are shown in Table 1. Characteristics of the representative sample and full sample are provided in Supplementary File 1, Table S1 and S2.

Table 1.

Institutional and resident characteristics in the three language regions (Full sample)

	German language region		French language region		Italian language region
	N a	%a	N a	%a	N a	%a
Institutional characteristics
Institutions	43	45.7	18	19.2	33	35.1
Type of facility
Residential home	4	9.3	0	0	22	66.7
General nursing home	29	67.4	12	66.7	9	27.3
Mixed/other	10	23.3	6	33.3	2	6.1
Nursing FTE/100 beds, median (IQR)	26.5	21.9–38.2	18.6	14.0-20.8	24.8	19.0-28.8
Auxiliary nurse FTE/100 beds, median (IQR)	25.1	22.7–29.3	40.8	33.9–44.6	41.5	33.1–45.9
% of auxiliary nurses, median (IQR)b	50.1	41.3–56.5	66.5	63.1–73.0	60.0	57.9–65.1
Number of beds, median (IQR)	74	54.0-120.0	61	48.8–74.8	71	54.0–83.0
Single rooms, median % (IQR)	90.6	73.7–100.0	86.7	67.1–92.0	93.9	83.0-100.0
Physician in charge
Personal family physician alone	19	44.2	6	33.3	17	51.5
Employed by the facility alone	7	16.3	5	27.8	3	9.1
Both	17	39.5	7	38.9	13	39.4
Resident characteristics
Residents	3660	50.5	1,232	17.0	2,352	32.5
Age (in years), median (range)	86	32–104	87	53–105	88	51–107
Years in institution, median (range)	2	0–57	2	0–31	2	0–36
Male resident	1189	32.5	336	27.3	663	28.2
Care dependencyc, median (IQR)	6	4–9	8	6–10	8	6–10
Hospital stay in the last 3 months	428	11.7	86	7.0	216	9.2
Surgery in the last 30 days	78	2.1	15	1.2	49	2.1
Mobility
Ambulant	2536	69.3	734	59.6	1,313	55.8
Wheelchair	1043	28.5	468	38.0	974	41.4
Bedridden	81	2.2	30	2.4	65	2.8
Urinary catheter	226	6.2	81	6.6	166	7.1
Vascular catheter	17	0.5	5	0.4	26	1.1
Temporal and/or spatial disorientation	2035	55.6	784	63.6	1,443	61.4
Incontinence (urinary and/or fecal)	2337	63.9	923	74.9	1,669	71.0
Proton pump inhibitor	1241	33.9	487	39.5	1,128	48.0
Decubital ulcer	150	4.1	46	3.7	126	5.4
Other chronic wounds	497	13.6	160	13.0	219	9.3

FTE, Full-time Equivalent; IQR, Interquartile Range; ^a if not stated otherwise; ^b Percentage auxiliary nurse FTE of total nursing FTE; ^c Score ranging from 0 (< 20 min of care per day) to 12 (> 220 min of care per day)

Antimicrobial use and indication by language region

Prevalence of antimicrobial use was 2.6%, with significantly higher prevalence in the French language region compared to the Italian and German regions. Prevalence of antimicrobial use for treatment, defined as percentage of residents receiving at least one antimicrobial for treatment, was 1.2% (95% CI 0.9–1.6) in the German language region, 2.2% (95% 1.6–2.8) in the Italian language region and 3.1% (95% CI 2.2–4.2) in the French language region (p < 0.001). Similarly, the prevalence of antimicrobial use for prophylaxis varied across regions: 0.5% (95% CI 0.3–0.7) in the German language region, 0.9% (95% CI 0.6–1.4) in the Italian language region and 2.0% (95% CI 1.3-3.0) in the French language region (p < 0.001).

Most antimicrobials were administered orally (89%, 185/209), followed by the parenteral (10%, 21/209) and other routes (1%, 3/209). Antibacterials accounted for 97% (203/209) of all antimicrobials prescribed. Among antimicrobials, 68% (142/209) were given for treatment and 32% (67/209) for prophylaxis. Most common indications for therapeutic antimicrobials use were urinary tract infections (UTI) (58%, 82/142), followed by respiratory tract infections (RTI) (18%, 25/142) and skin and soft tissue infections (SSTI) (9%, 13/142). Other indications included ear-nose-mouth infections [5], gastrointestinal infections [4], surgical site infections [3], systemic infections of unclear focus [3], genital infections [1], and infections not otherwise specified [4]. In 2 cases indication was not reported. Indication frequencies were similar across language regions, apart from SSTI being more frequent than RTI in the German language region, while the opposite was observed in the remaining regions. The overall proportion of antimicrobials prescribed for prophylaxis was higher in the French language region (41%, 26/64) than in the Italian (29%, 24/82) and German language region (27%, 17/63).

Figure 1 shows the distribution of antimicrobial substances by region (A) and indication (B). The most frequently prescribed substances were aminopenicillins in the French and Italian language regions, and aminopenicillins together with TMP/SMX in the German language region. Of note, nitrofurantoin and amoxicillin/clavulanic acid (AMC) were the most used substances for UTI in the German and French language region, respectively, while fluroquinolones and TMP/SMX were most used in the Italian language region (see Supplementary File 1, Figure S1). Most frequently used substances for prophylaxis were TMP/SMX, nitrofurantoin and AMC. According to the AWaRe classification from the World Health Organization [8], most antibacterials were in the Access group (66%, 137/209) and no substances were in the Reserve group. The proportion of antimicrobials in the Watch group was 21% (13/63) in the German, 36% (23/64) in the French and 44% (36/82) in the Italian language region (see Supplementary File 1, Figure S2).

Fig. 1.

Proportion of antimicrobial substances prescribed by (A) language region and (B) by reported indication (N = 209)

Absolute numbers of prescriptions are shown within stacked bars. Numbers provided below stacked bars represent the number of residents receiving at least one antimicrobial. UTI, urinary tract infection; RTI, respiratory tract infection; SSTI, skin and soft tissue infection; TMP/SMX, trimethoprim/sulfamethoxazole.

AMS elements and perception by language region

Overall, 52% of institutions had at least one AMS element; the proportion was 79% for the Italian, 61% for the French, and 28% for the German language region (p-value < 0.001). The most common AMS element was having a surveillance system on antimicrobial consumption by substance in place (26%, 24/94), written guidelines for antimicrobial use (23%, 22/94) and pharmacist support for selection and prescription of reserve antimicrobials (20%, 19/94).

Figure 2 shows the presence of AMS elements stratified by region. Written guidelines for antimicrobial use and surveillance systems on antimicrobial consumption by substance were more common in the Italian and French language region than in the German language region. Reporting of antimicrobial use to prescribing physicians was available in 10% (9/94) of cases.

Fig. 2.

Percentage proportion of Swiss LTCF adopting AMS elements stratified by language region (full sample, N = 94)

Absolute numbers are shown right of each bar. AMR, antimicrobial resistance; AMS, antimicrobial stewardship.

Overall, 87% of the institutions representatives considered the subject of AMR very important or rather important, 35% thought that additional measures were needed to reduce antimicrobial use in their LTCF. When asked about which measures would be needed for this objective, 21% cited guidelines on rational antimicrobial prescription, 17% educational activities on the topic and 19% less diagnostic testing without clear indication. The proportion of institution representatives considering the subject of antimicrobial use and AMS very or rather important was higher in the French and Italian language regions compared to the German one, with similar findings across the remaining questions (see Supplementary File 1, Table S3).

Factors associated with antimicrobial use

Table 2 shows the results of the univariable and multivariable analysis of institutional and resident-level factors associated with antimicrobial use. In the multivariable analysis, the factor with strongest association was being a resident in a LTCF from the French language region (aOR 2.99, 95% CI 1.76–5.01). Other significant factors were hospitalisation in the previous 3 months or surgery in the previous 30 days (aOR 2.19, 95% CI 1.50–3.19), urinary catheter use (aOR 2.10, 95% CI 1.36–3.24), use of PPI (aOR 1.49, 95% CI 1.11–2.00) and chronic wounds (aOR 1.47, 95% CI 1.04–2.10). Neither the number of implemented AMS elements nor any single AMS element was associated with a reduction in antimicrobial use in the univariable analysis and were therefore not included in the multivariable analysis.

Table 2.

Univariable and multivariable regression analysis regarding antimicrobial use (N = 191) in Swiss long-term care residents (full sample, fixed effects)

	Univariable analysis			Multivariable analysis Fixed effects
	OR	95% CI	p-value	aOR	95% CI	p-value
Resident-related factors
Age > 85 years	1.14	0.85–1.54	0.37
Male gender	1.17	0.86–1.58	0.31
Care dependencya	1.11	1.05–1.17	< 0.001	1.03	0.97–1.09	0.38
Use of proton pump inhibitor	1.68	1.26–2.24	< 0.001	1.49	1.11-2.00	0.008
Disorientation	1.08	0.81–1.46	0.59
Wheelchair or bedridden	1.62	1.22–2.16	0.001	1.07	0.76–1.50	0.71
Urinary catheter	2.78	1.83–4.09	< 0.001	2.10	1.36–3.24	< 0.001
Incontinence	1.69	1.21–2.41	0.003	1.43	0.97–2.09	0.07
Chronic wound/decubital ulcer	1.98	1.41–2.73	< 0.001	1.47	1.04–2.10	0.03
Hospitalisation last 3 months/Surgery last 30 days	2.24	1.54–3.17	< 0.001	2.19	1.50–3.19	< 0.001
Institutional factors
Language
German-speaking	Ref			Ref
French-speaking	3.23	2.25–4.65	< 0.001	2.99	1.76–5.01	< 0.001
Italian-speaking	1.87	1.32–2.66	< 0.001	1.41	0.82–2.41	0.21
Type of facility
Residential home	Ref			Ref
General nursing home	0.95	0.68–1.32	0.75	0.90	0.54–1.51	0.7
Mixed/other	0.57	0.37–0.89	0.01	0.61	0.32–1.68	0.14
Nursing FTE/100 beds	0.97	0.96–0.99	< 0.001	1.00	0.98–1.02	0.88
Auxiliary nurse FTE/100 bedsb	1.01	1.0-1.03	0.02
Number of beds	1.00	1.00–1.00	0.97
% of single beds	1.00	1.00-1.01	0.20
Physician in charge
Personal family physician alone	Ref
Employed by the facility alone	1.23	0.83–1.81	0.31
Both	0.78	0.56–1.07	0.12
AMS elements
AMS score	1.03	0.92–1.13	0.62
Regular teaching on rational antimicrobial use	1.31	0.79–2.04	0.26
Written guidelines on rational antimicrobial use	1.00	0.71–1.38	0.99
Antimicrobial consumption surveillance by substance	1.28	0.92–1.75	0.13
Diagnostic stewardship toolc	1.29	0.63–2.35	0.44
Local resistance data accessible for physicians	0.86	0.50–1.38	0.56
Antimicrobial restriction for certain substances	1.18	0.83–1.64	0.33
Pharmacist support	1.30	0.90–1.82	0.15
Therapeutic guidelines with list of antimicrobials	0.85	0.56–1.24	0.42
Reporting of antimicrobial use to prescribing physicians	0.77	0.57–1.03	0.08

aOR; adjusted Odds Ratio; CI, Confidence Interval; HCW, Healthcare Worker, IQR; Interquartile Range; FTE, Full-Time Equivalent; IPC, Infection Prevention and Control; HAI, Healthcare Associated Infection; Ref, Reference

^a Score ranging from 1 (< 20 min of care per day) to 12 (> 220 min of care per day)

^b Not included in the multivariable model due to suspected multicollinearity with the variable Nursing FTE/100 beds

^c System which reminds healthcare workers of importance of microbiologic diagnosis for antimicrobial treatment

Discussion

In this study, we aimed at characterizing the differences in antimicrobial use in Swiss LTCF across language regions and to identify independent factors associated with it, as well as to assess AMS elements. Antimicrobial use was highest in the French language region, a finding that remained significant in the multivariable analysis. Prophylaxis accounted for a substantial proportion of antimicrobial prescription, particularly in the French language region. Prescribed substances also varied across language regions. Adoption of AMS elements was low and their presence was not associated with reduced antimicrobial use.

The French language region showed the strongest association with antimicrobial use, independently of known risk factors, institutional characteristics and AMS elements. Similar findings have been shown previously in the outpatient setting [9] and in LTCF in a smaller study [10]. This suggests that other additional factors must be taken into account to explain geographical variation. For example, cultural perceptions, such as expectation of receiving antimicrobials and knowledge (or lack thereof) on AMR, can lead to higher antimicrobial prescription by treating physicians [11]. Such factors have been suggested as possible explanation of antibiotic prescribing differences between two neighbouring countries, France and Germany, that may reflect some of the socio-cultural differences between the French and German language regions in Switzerland [12]. In line with these considerations, French primary care physicians reported in a more recent survey being pressured to prescribe antibiotics in about a third of consultations, particularly by elderly patients with comorbidities [13]. Also physician- and nursing staff-related factors, such as time constraint, ineffective communication within the treating team, and defensive medicine, and setting-related factors, such as difficulties and delays in obtaining results of diagnostic tests, are associated with higher antimicrobial prescription [11, 14–16]. Evidence on these additional factors influencing antibiotic prescription in Swiss LTCF is limited and conclusive comparisons between language regions are currently not possible.

We observed geographical variation also in the indication of antimicrobial use, similar to the European PPS [17]. Prophylaxis was more frequent than any single therapeutic indication in the French language region and was common overall. We did not assess the indication of each prophylaxis, but most prescribed substances in the French language region - fosfomycin and nitrofurantoin - are consistent with UTI prophylaxis, similar to the pattern observed in European PPS [17]. In this regard, we did not assess facility-specific guidelines (where available), but Swiss guidelines either do not address antibiotic prophylaxis for recurrent UTI, recommend it as a temporary option after non-antibiotic prophylactic measures have failed, or recommend against it [18–20]. Similarly, both French and German guidelines recommend antibiotic prophylaxis for recurrent UTI only after non-antibiotic measures have failed and for a limited period of time [21, 22]. UTI were also the most common indication for antimicrobial treatment overall, with prescribed substances also varying across language regions. Nitrofurantoin and AMC were most used in the German and French language regions, while fluoroquinolones and TMP/SMX in the Italian language region. This finding may be relevant for AMS programmes, as fluoroquinolones are no longer recommended as first line empiric therapy for uncomplicated UTI due their potential for adverse effects and ecological consequences. Of note, a previous study in the primary care setting has shown a similar geographical prescription pattern for fluoroquinolones, and identified associated factors, such as higher physician age and years of practice experience [23]. Nonetheless, further characterization of prescribing practices in LTCF is needed to evaluate their appropriateness in relation to UTI classification, regional resistance patterns and adherence to local guidelines [18, 19, 22].

The European Centre for Disease Prevention and Control (ECDC) officially recommends AMS programmes in LTCF since 2017, but adoption varies significantly across European countries [6, 17, 24]. In the last European PPS, 38.8% of LTCF did not have any AMS element and only 24.2% had a surveillance system on antimicrobial use in place [17]. Comparatively, in our study 48% of institutions did not have any AMS element. Interestingly, the German language region had both the lowest AMS adoption and lowest antimicrobial use, while the French language region, which showed the highest antimicrobial use, had a substantially higher adoption of AMS elements. Also, neither the total number of AMS elements nor individual elements were associated with antimicrobial use in the multivariable analysis. A possible explanation is that AMS elements are more likely to be adopted in regions where high antimicrobial prescribing is recognized as an issue and may already have contributed to reducing antimicrobial use from a previously higher baseline. Alternatively, AMS elements may lack effectiveness, may not be sufficiently tailored to the specific setting of LTCF or local prescribing practices, or their implementation may be suboptimal. These findings highlight the limitations of surveys that assess only the presence of AMS elements and underscore the importance of surveillance systems capable of evaluating both the implementation and the actual impact of these elements on prescribing behaviour. AMS adoption was overall low, with about half of Swiss LTCF with no AMS element and most LTCF adopting a limited number of elements. This is not surprising, as LTCF present several barriers to AMS implementation, including limited financial and staff resources [25]. Ideally, LTCF should be able to perform evidence-informed decisions and implement only highly effective and sustainable AMS elements tailored to the local needs, therefore optimizing resources. In reality, this strategy is faced with two major issues. First, surveillance systems needed to assess the local patterns of antimicrobial prescription are often lacking (only 25.5% of Swiss LTCF in our study). Second, evidence on the effectiveness of AMS interventions in the LTCF setting is limited, with multiple systematic reviews showing significant heterogeneity and therefore limited generalizability [26–29]. Most high-quality studies achieved nonetheless positive outcomes, mostly adopting written guidelines and education strategies. While the former is relatively common in LTCF of the European PPS and in our study, the latter was the least common AMS element among Swiss institutions. This may be due to implementation challenges, such as the heterogeneity of prescribing physicians (over whom LTCF often have limited influence), time constraints and high turnover of LTCF staff [25]. Similarly, feedback on antimicrobial use has been previously identified as a promising behavioural change technique, but only 9.6% of Swiss LTCF reported data on antimicrobial use to prescribing physicians [29].

Within the European PPS, factors associated with antimicrobial use have been identified both at the institutional and resident level [6]. At the institutional level, mixed type LTCF (institutions providing mixed services, differently from general nursing homes or residential homes) and LTCF with smaller numbers of beds were associated with higher antimicrobial use. Factors at resident level showed weaker associations, with presence of a vascular catheter and surgery in the previous 30 days being the most relevant ones. Comparatively, in our study the only institutional factor showing association with antimicrobial use was the French language region. At the resident level, recent hospitalisation or surgery showed the strongest association, similarly to the European findings, followed by two potentially modifiable factors: presence of a urinary catheter and use of PPI. The former is a known risk factor for catheter-associated UTI (CAUTI) and, although we did not assess the appropriateness of indication for urinary catheters, IPC interventions have shown potential for reduction in CAUTI incidence, and therefore indirectly in antimicrobial use, also without significant change in catheter utilization rates [30]. Although PPI use could also be a marker of frailty, comorbidities or polypharmacy that were not fully captured in the study, it is also associated with increased risk of Clostridioides difficile infection, AMR and, especially in patients with dementia, community-acquired pneumonia [31–33]. Interventions for PPI deprescription have shown positive results in LTCF, but their effect on antimicrobial use is unclear [34–36].

The main strengths of our study were the large sample of LTCF across the entire country, the collection of data on risk factors at the resident level, and the use of a standardised data collection tool that allows for international comparison. Our study also has several limitations. First, we did not assess the indication for prophylaxis and, overall, the appropriateness of antimicrobial use. Second, the study was performed outside of the viral respiratory season, where antimicrobial use could be higher due to increased incidence of RTI. Third, we only assessed the presence of AMS elements and not their quality or implementation. Fourth, our sample, which was partly a convenience sample, may have introduced selection bias, thereby limiting the generalizability of the results. Finally, assessment of perception on AMR and AMS among LTCF may not be representative of each facility, as only individual representatives were interviewed.

Conclusions

Our study suggests that geographical differences in antimicrobial use in Swiss LTCF cannot be fully explained by traditional risk factors alone, implying that AMS programmes should consider this variation and tailor interventions to the local context. With this regard, involvement of relevant stakeholders in the development and implementation of such interventions is essential to identify barriers and facilitators. Surveillance systems are also needed to better characterize regional needs and to evaluate the effectiveness of AMS programmes. Finally, the considerable proportion of antimicrobials prescribed for prophylaxis warrants further investigation to understand the underlying causes and holds potential as target for AMS interventions in Swiss LTCF.

Supplementary Information

Below is the link to the electronic supplementary material.

Abbreviations

AMC

Amoxicillin/clavulanic acid

AMR

Antimicrobial resistance

AMS

Antimicrobial stewardship

aOR

Adjusted odds ratio

CAUTI

Catheter-associated urinary tract infection

CI

Confidence interval

ECDC

European centre for disease prevention and control

FTE

Full-time equivalent

HAI

Healthcare-associated infection

HALT

Healthcare-associated infections in European long-term care facilities

IQR

Interquartile ranges

LTCF

Long-term care facilities

OR

Odds ratio

PPI

Proton-pump inhibitor

PPS

Point-prevalence survey

RTI

Respiratory tract infection

SSTI

Skin and soft tissue infection

TMP/SMX

Trimethoprim/sulfamethoxazole

UTI

Urinary tract infection

Author contributions

ST drafted the manuscript and contributed to data analysis. DF conceptualized and supervised the study including data collection and analyses, and drafted the manuscript. EG co-conceptualized the study and performed data collection. CG, TK, SPK, VP and MS co-conceptualized the study. FG contributed to recruitment of institutions, data management and analyses. PK co-conceptualized the study, supervised data management and analyses and drafted the manuscript. All authors critically revised the manuscript and approved the final version.

Funding

The study was funded by the Swiss Federal Office of Public Health.

Data availability

The datasets used and/or analysed during the current study are not publicly available but are available from the corresponding author on reasonable request.

Declarations

Ethics approval and consent to participate

The study was approved by the ethics committee of Eastern Switzerland (No 2024 − 00654). No individual informed consent was required, but residents who declined participation were excluded.

Competing interests

The authors declare no competing interests.