ORIGINAL RESEARCH article

Front. Pharmacol., 05 January 2026

Sec. Pharmacology of Infectious Diseases

Volume 16 - 2025 | https://doi.org/10.3389/fphar.2025.1721689

Antibiotic use for respiratory tract infections in nursing homes: a multicentre cross-sectional study

  • 1. Fundació Institut Universitari per a la Recerca a l’Atenció Primària de Salut Jordi Gol, Barcelona, Spain

  • 2. CIBER en Enfermedades Infecciosas Instituto Carlos III, Madrid, Spain

  • 3. Department of Public Health, Research Unit for General Practice, University of Southern Denmark, Odense, Denmark

  • 4. Universitat Autònoma de Barcelona, Bellaterra, Spain

  • 5. Geriatrics Department, Hospital Universitario Ramón y Cajal (IRYCIS), Madrid, Spain

  • 6. Pharmacology Department, Complejo Hospitalario Universitario de Canarias, Santa Cruz de Tenerife, Spain

  • 7. Internal Medicine Department, Hospital Universitario La Princesa, Instituto de Investigación Sanitaria (IIS-Princesa), Madrid, Spain

  • 8. Group B21-23R, Health Research Institute of Aragon (IISA), Zaragoza, Spain

  • 9. Network for Research on Chronicity, Primary Care, and Health Promotion, Zaragoza, Spain

  • 10. Primary Care Department, Universidad Zaragoza, Zaragoza, Spain

  • 11. Geriatrics Department, Hospital San Juan de Dios, Zaragoza, Spain

  • 12. Nursing Home, Aragon Institute of Social Services (IASS), Borja, Spain

  • 13. Institut Català de la Salut, Barcelona, Spain

Abstract

Introduction:

To evaluate the use of antibiotic treatment for respiratory tract infections (RTIs) in nursing homes in Spain, assess whether they were indicated based on current guidelines, and identify predictors of both use and inappropriate use of antibiotics.

Methods:

Cross-sectional study carried out in 34 nursing homes in five areas in Spain. Nursing staff self-registered residents related to antibiotic use for RTIs in February-April 2023. Nursing staff recorded data on residents with RTIs, including demographics, symptoms, diagnoses, and antibiotic use. Logistic regression models were applied to identify predictors of antibiotic prescription and inappropriate use based on clinical guidelines.

Results:

Among 533 recorded RTI cases, the most common diagnoses were common cold (19.7%) and acute bronchitis (18.8%). Antibiotics were prescribed in 77.5% of cases, mainly for otitis media, tonsillitis, and pneumonia, with amoxicillin-clavulanate being the most frequent (34%). Of 328 prescriptions assessed, 63.1% were deemed unnecessary. Factors strongly associated with antibiotic use included confusion (odds ratio 4.72; p = 0.005), perceived demand for antibiotics (OR 3.83; p < 0.001), and fever (OR 3.27; p = 0.005), whereas rhinorrhea reduced the likelihood of prescription (OR 0.23; p < 0.001).

Discussion:

The findings reveal substantial overuse of antibiotics for RTIs in nursing homes and highlight the need for targeted interventions to promote guideline-based prescribing and reduce inappropriate use.

Introduction

In recent years, Europe has experienced a significant increase in the elderly population, reshaping the healthcare landscape as older adults constitute a growing proportion of society. This demographic shift has led to increased demand for long-term care facilities. Globally, the proportion of people over 60 years of age is projected to double between 2015 and 2050, with age-related dependency expected to rise accordingly (). Nursing homes aim to provide a home-like environment, yet they often serve as communal settings where individuals with complex health conditions live in close quarters and share caregivers (). As a result, nursing home residents are particularly vulnerable to frequent and severe infections, with respiratory and urinary tract infections being the most common ().

The Antimicrobial Consumption in the European Union (ESAC-Net) report recently updated the prevalence of antimicrobial use in long-term care facilities across 18 European Union countries for the period 2023–2024. The findings indicated an overall prevalence of antimicrobial use of 4.1%, with Spain reporting one of the highest consumption rates at 5.1% (). At least 60% of prescriptions issued in nursing homes are estimated to be inappropriate, contributing to the development of multidrug-resistant pathogens, with nearly one-third of these antimicrobials administered prophylactically (). Additionally, the use of non-first-line antibiotics, especially broad-spectrum ones, exacerbates antimicrobial resistance, leading to higher morbidity, mortality, and societal costs (). Nursing home residents experience significantly higher rates of antibiotic-resistant infections compared to older adults living independently in the community (; ). This increased risk is parallel by greater antibiotic consumption as individuals of the same age residing in long-term care facilities are prescribed antibiotics more frequently than their community-dwelling counterparts (). These patterns highlight the unique antimicrobial challenges faced by institutionalized older populations and emphasize the importance of targeted antibiotic stewardship in these settings. The aim of this study is to quantify the prescribing rates of antibiotics for residents with respiratory tract infections (RTIs) in Spanish nursing homes, estimate the proportion of prescriptions that were theoretically not indicated according to current guidelines, and identify the factors that predict both antibiotic use and inappropriate antibiotic use.

Materials and methods

Study design

This was a cross-sectional study. For this study, we used the information collected during the first-year registration of a before and after study aimed at evaluating the impact of a multifaceted intervention on antibiotic prescribing among residents in nursing homes (). The participants who documented the infections were mainly nurses but also doctors, nurse assistants, or nurse helpers in each nursing home.

Audit registrations

The participants completed the audit form documenting all infections in nursing homes throughout a three-month period, from February to April 2023. This form had two sides. The first side collected general information about the infection, including demographic data, type of infection, details of antibiotic treatment (such as whether antibiotics were administered and, if so, which type), allergies, and referrals to other healthcare settings. The second side of the form gathered detailed information on symptoms, signs, diagnosis, and tests used. In autumn 2022, one nursing home or one ward from a large nursing home in each of the five regions of Spain was recruited for a pilot study to assess whether the template used was understandable. Participants were asked to consecutively register all consultations related to RTIs, but they did not receive any guidance on the definition of as this was designed to be a pragmatic study. However, they were given a simple instruction sheet on how to complete the registration template. Each case was recorded on one line, with participants typically only needing to tick boxes, avoiding written responses.

Statistical analysis

The potentially unnecessary antibiotic use was defined as this antibiotic given to a patient with a suspected RTI not complying with the minimum criteria for being administered based on national and international guidelines (; ; ; ; ; ; ) (Table 1). This analysis was conducted only for patients with a clear diagnosis of RTI. We used chi-square and Student t-tests to compare qualitative and quantitative variables, respectively. We also estimated the patterns of antibiotic prescribing and its appropriateness with logistic regression models. Antibiotic prescription was considered the dependent variable (yes/no). These models controlled for patients’ characteristics, signs and symptoms, as well as for the demand for antibiotics by the resident and/or relatives. Hosmer and Lemeshow goodness of fit and collinearity were calculated. Statistical significance was considered at P < 0.05. The data were analyzed with the R v. 4.3 statistical program.

TABLE 1

InfectionWhen to administer antimicrobialsFirst-line antimicrobialIn case of allergy to penicillinAlternative antimicrobialsHospital referral
Common coldNoSymptomaticSymptomaticSymptomaticPoor progressiona
Acute pharyngitis or tonsillitisOnly that caused by group A streptococcusbPenicillin V 1.000 mg/8 h, 7–10 dClindamycin 300 mg/8 h, 10 d, or any macrolideAmoxicillin 500 mg/8 h, 10 d, or cefadroxil 500 mg/8 h, 10 d. Amoxicillin and clavulanate 500–125 mg/8 h, 10 d if relapsePoor clinical evolutiona, suspicion of locoregional complications or Lemierre’s syndrome. Refer to ENT if cervical adenitis or recurrent peritonsillar abscesses are present
Acute rhinosinusitisAntibiotics should not be given, except if signs and symptoms do not improve within 10 days, severe symptoms appear from day 3, or symptoms worsen from day 5 onwardAmoxicillin 1 g/8 h, 5 dcRespiratory fluoroquinolone 5 ddAmoxicillin and clavulanate 875–125 mg/8 h, 7–10 d or respiratory fluoroquinolone 7 d if relapse or poor evolutiondPersistent fever >39 °C, periorbital oedema, inflammation or erythema, severe headache, neurological focal signs, meningeal signs, confusion, suspected orbital infection, or diplopia. Refer to ENT if chronic infection (>12 weeks) or >4 episodes per year
Acute otitis mediaAntibiotics should not be given, except in the presence of risk factors for poor outcomeseAmoxicillin 1 g/8 h, 5 dcAny macrolideAmoxicillin and clavulanate 875–125 mg/8 h,7–10 d if poor evolutionChronic otitis (>1 week), mastoiditis, meningitis, facial paralysis, or suspected intracranial complication
InfluenzaNoSymptomaticSymptomaticOseltamivir 75 mg/12 h, 5 dfSuspected pneumonia, severe condition, confusion, oxygen saturation <92%, significant comorbidity, respiratory rate ≥30 breaths/min, systolic blood pressure <90 mmHg or diastolic <60 mmhg
Acute bronchitisIn acute bronchitis, antibiotics should not be given, except in specific situationsgSymptomaticSymptomaticAmoxicillin and clavulanate 500–875/125 mg/8 h, 5 dSuspected pneumonia, severe condition, confusion, oxygen saturation <92%, significant comorbidity, respiratory rate ≥30 breaths/min, systolic blood pressure <90 mmHg or diastolic <60 mmhg
PneumoniaAlwaysAmoxicillin and clavulanate 500–875/125 mg/8 h, 5-7 dh,iRespiratory fluoroquinolone 5 dd,h,iRespiratory fluoroquinolone 5 dd,h,iRefer to hospitali
COPD exacerbationOnly if sputum is purulent and in all cases of very severe COPD exacerbationsAmoxicillin and clavulanate 500 ó 875–125 mg/8 h, 5 dhRespiratory fluoroquinolone 5 dd,hRisk of Pseudomonasj: ciprofloxacin 750 mg/12 h or levofloxacin 500 mg/12 h, 10 dConfusion, cyanosis, respiratory rate ≥30 breaths/min, severe dyspnoea, oxygen therapy required, inability to remain at home, or oxygen saturation <92%

Current recommendations on antimicrobial therapy for residents with respiratory tract infections.

a

> 2 weeks duration of symptoms, when swallowing is impaired, lingual pharyngitis with airway-digestive tract obstruction, and/or suspected lymphomatous infiltration.

b

Antibiotics should be given in immunocompromised patients, those with a history of rheumatic fever, signs of severity (poor general condition, ear pain, and/or severe tonsillar inflammation), and in cases of pharyngitis during a Group A β-hemolytic streptococcus outbreak in the facility. In other cases, it is essential to distinguish streptococcal pharyngitis from viral pharyngitis: fever >38.5 °C, absence of cough, pharyngo-tonsillar exudate, and painful cervical adenopathy. If fewer than 2 of these criteria are present, do not give antibiotics; if 2 or more, perform rapid antigen testing (Strep A) and treat based on the result. If Strep A testing is not available, give antibiotics if two or more criteria are met.

c

If there is no favorable evolution within 48–72 h, use an alternative antibiotic.

d

The use of levofloxacin 500 mg/day is recommended over moxifloxacin 400 mg/day, due to the latter’s potential association with fulminant hepatitis and blistering skin reactions (2008 alert), risk of QT, interval prolongation (2010 alert), and because it should be reserved as second-line treatment for tuberculosis.

e

Any of the following: severe symptoms (high fever with intense pain and vomiting), presence of otorrhea, serious underlying disease, recurrent otitis media, bilateral otitis, or tympanic membrane perforation.

f

Its use is recommended in any of the following situations: elderly >85 years, frail individuals, and/or those with significant comorbidity.

g

Marked deterioration of general condition, frail individuals, and elderly with significant comorbidities.

h

Check evolution at 48–72 h. If there is no improvement, refer to hospital.

i

Residents under 75 years of age may be treated in the facility and monitored over 48–72 h, provided they do not present any of the following: significant comorbidities, confusion, respiratory rate ≥30 breaths/min, systolic blood pressure <90 mmHg or diastolic <60 mmHg, O2 saturation <92%, marked abnormalities on chest X-ray, inability to adhere to treatment in the facility, decompensation of underlying disease, intolerance to oral treatment, or immunosuppression.

j

Use of 4 antibiotic regimens in the past year, oral corticosteroids in the last 2 weeks, isolation of Pseudomonas in a previous sputum culture, presence of significant bronchiectasis, recent hospitalization, or FEV1 <30%.

Results

Characteristics of the RTIs

A total of 34 nursing homes participated in the registration period. Nursing staff personnel documented a total of 533 RTIs, of which 346 were in women (64.9%). The median age was 88 years (interquartile range [IQR] 82–92 years). The most frequent diagnosis was common cold, with 105 cases (19.7%), followed by acute bronchitis (100 cases [18.8%]) other RTIs (89 cases [16.7%), and pneumonia (74 residents, 13.9%). Cough was the most frequently observed symptom among residents with RTIs, present in 342 cases (64.2%), followed by increased sputum production and breathlessness, observed in 43.9% and 38.5% of cases, respectively. The most common test performed on these patients was the COVID-19 antigen test, used in 26.6% of cases, while chest X-rays, C-reactive protein rapid tests, and rapid antigen detection tests for streptococcal infection were seldom used (Table 2).

TABLE 2

CharacteristicsTotalMenWomenP value
Number or registrations/infections533187346
Age, year, median [IQR]88 [82, 92]86 [78, 91]89 [83, 93]<0.001
Prior symptom duration, days, median [IQR]2 [1, 3]2 [1, 3]2 [1, 3]0.894
General signs and symptoms, n (%)
 Fever136 (25.5)59 (31.6)77 (22.3)0.025
 Shaking chills83 (15.6)41 (21.9)42 (12.1)0.004
 Confusion122 (22.9)44 (23.5)78 (22.5)0.880
 Joint and muscle pains50 (9.4)20 (10.7)30 (8.7)0.542
 No general symptoms261 (49.0)84 (44.9)177 (51.2)0.199
Respiratory tract signs and symptoms, n (%)
 Cough342 (64.2)123 (65.8)219 (63.3)0.635
 Rhinorrhea138 (25.9)47 (25.1)91 (26.3)0.849
 Otorrhea3 (0.6)1 (0.5)2 (0.6)1.000
 Odynophagia56 (10.5)15 (8.0)41 (11.8)0.220
 Tonsillar exudate18 (3.4)9 (4.8)9 (2.6)0.272
 Tender cervical glands19 (3.6)5 (2.7)14 (4.0)0.568
 Dyspnea205 (38.5)75 (40.1)130 (37.6)0.631
 Increase in sputum volume234 (43.9)86 (46.0)148 (42.8)0.534
 Purulent sputum80 (15.0)25 (13.4)55 (15.9)0.514
 Bronchospasm61 (11.4)21 (11.2)40 (11.6)1.000
 None of the above20 (3.8)8 (4.3)12 (3.5)0.818
Diagnosis, n (%)
 Common cold105 (19.7)35 (18.7)70 (20.2)0.760
 Acute otitis media3 (0.6)1 (0.5)2 (0.6)1.000
 Acute sinusitis0 (0.0)0 (0.0)0 (0.0)NA
 Acute pharyngitis23 (4.3)8 (4.3)15 (4.3)1.000
 Acute tonsillitis9 (1.7)5 (2.7)4 (1.2)0.344
 Acute bronchitis100 (18.8)33 (17.6)67 (19.4)0.713
 Pneumonia74 (13.9)21 (11.2)53 (15.3)0.241
 COPD exacerbation40 (7.5)19 (10.2)21 (6.1)0.124
 Bronchoaspirative RTI54 (10.1)25 (13.4)29 (8.4)0.095
 Influenza23 (4.3)5 (2.7)18 (5.2)0.251
 COVID-19 infection13 (2.4)5 (2.7)8 (2.3)1.000
 Other RTIsa89 (16.7)30 (16.0)59 (17.1)0.860
Tests performed, n (%)
 Rapid antigen detection test2 (0.4)0 (0.0)2 (0.6)0.765
 C-reactive protein rapid test12 (2.3)5 (2.7)7 (2.0)0.859
 Chest X-ray36 (6.8)17 (9.1)19 (5.5)0.162
 COVID-19 test142 (26.6)48 (25.7)94 (27.2)0.786
 No testing320 (60.0)110 (58.8)210 (60.7)0.743
Antibiotic treatment, n (%)413 (77.5)146 (78.1)267 (77.2)0.896
Duration of the antibiotic course, days, median [IQR]7 [7, 7]7 [7, 7]7 [7, 7]0.478
Antibiotic given, n (%)
 Penicillin V0 (0.0)0 (0.0)0 (0.0)NA
 Amoxicillin15 (2.8)7 (3.7)8 (2.3)0.497
 Amoxicillin and clavulanate181 (34.0)64 (34.2)117 (33.8)1.000
 Macrolide or clindamycin30 (5.6)12 (6.4)18 (5.2)0.701
 Cephalosporin58 (10.9)17 (9.1)41 (11.8)0.406
 Fosfomycin9 (1.7)1 (0.5)8 (2.3)0.243
 Trimethoprim + sulfamethoxazole9 (1.7)1 (0.5)8 (2.3)0.243
 Quinolone91 (17.1)34 (18.2)57 (16.5)0.704
 Another antibiotic25 (4.7)12 (6.4)13 (3.8)0.241

General characteristics of the residents with respiratory tract infections from the nursing homes that completed the registration audit.

COPD, chronic obstructive pulmonary disease; IQR, interquartile range; NA, not available; RTI, respiratory tract infection.

a

Any other RTI, that, according to professional judgment, cannot be classified under any of the above diagnoses.

Figure 1 shows the percentage of symptoms presented by patients for each of the RTI diagnoses. Each column represents a diagnosis and indicates the percentage of symptoms that residents present for each diagnosis. It helps to interpret how each condition is diagnosed. Among the specific respiratory tract symptoms, cough was particularly predominant in the so-called lower RTIs—i.e., acute bronchitis, pneumonia, and chronic obstructive pulmonary disease (COPD) exacerbations—but was also common in cases of flu and common cold. Rhinorrhea was more frequent among residents with common cold, tonsillar exudate in those with acute tonsillitis, and otorrhea in residents with acute otitis media. Dyspnea was highly prevalent in residents with lower RTIs, mainly bronchoaspirative RTIs, and the increase in the volume of expectoration was greater among those with COPD exacerbations and acute bronchitis. Among systemic symptoms, fever was more prevalent in lower RTIs and flu infections, with chills being more prevalent among influenza patients. Confusion was more common in residents with pneumonia and bronchoaspirative RTIs, while arthromyalgias were mostly seen in patients with flu. However, most residents with RTIs presented no general symptoms, except for those with flu infection.

FIGURE 1

Antibiotic use for RTIs

As shown in Table 3, antibiotics were administered to 413 residents (77.5%), with slightly higher rates among men compared to women. Certain RTIs were consistently treated with antibiotics, such as acute otitis media and acute tonsillitis. A total of 71 pneumonia episodes (95.9%) were treated with antibacterial agents. Similarly, a high number of cases of acute bronchitis and acute pharyngitis were also associated with high antibiotic prescribing rates, exceeding 90% of cases. Antibiotics were prescribed in 85% of acute COPD exacerbations and 74.1% of bronchoaspirative RTIs. Even in predominantly viral infections—such as COVID-19, influenza, and the common cold—antibiotics were used in 61.5%, 47.8%, and 29.5% of cases, respectively. The most used antibiotic was the combination of amoxicillin and clavulanate, prescribed in 34% of all RTI cases, followed by quinolones and cephalosporins, which accounted for 17.1% and 10.9% of all antibiotics administered, respectively. Notably, amoxicillin alone was used in only 2.8% of infections, and penicillin V was not prescribed in any RTI case (Table 2).

TABLE 3

DiagnosisTotalMenWomenP value
Common cold31/105 (29.5)10/35 (28.6)21/70 (30.0)0.858
Acute otitis media3/3 (100.0)1/1 (100.0)2/2 (100.0)1.000
Acute sinusitis0/0 (0.0)0/0 (0.0)0/0 (0.0)NA
Acute pharyngitis21/23 (91.3)8/8 (100.0)13/15 (86.7)0.971
Acute tonsillitis9/9 (100.0)5/5 (100.0)4/4 (100.0)0.353
Acute bronchitis92/100 (92.0)29/33 (87.9)63/67 (94.0)0.455
Pneumonia71/74 (95.9)21/21 (100.0)50/53 (94.3)0.326
COPD exacerbation34/40 (85.0)18/19 (94.7)16/21 (76.2)0.040
Bronchoaspirative RTI40/54 (74.1)19/25 (76.0)21/29 (72.4)0.623
Influenza11/23 (47.8)2/5 (40.0)9/18 (50.0)0.375
COVID-19 infection8/13 (61.5)4/5 (80.0)4/8 (50.0)0.616
Other RTIsa85/89 (95.5)29/30 (96.7)56/59 (94.9)0.883
Total413/533 (77.5)146/187 (78.1)267/346 (77.2)0.811

Proportion of residents treated with antibiotics according to diagnosis.

COPD, chronic obstructive pulmonary disease; NA, not available; RTI, respiratory tract infection.

a

Any other RTI, that, according to professional judgment, cannot be classified under any of the above diagnoses.

Out of the total 413 cases of RTIs treated with antibiotics, 328 involved clear diagnoses, while the remaining cases were treated in residents with other types of RTIs. In 207 cases with a clear diagnosis (63.1%), antibiotic treatment was not indicated according to clinical guidelines.

Predictive factors associated with antibiotic prescribing in residents with RTIs

As shown in Table 4, the most predictive factors for antibiotic use were the presence of confusion (odds ratio [OR] 4.72; p < 0.01), perceived demand for antibiotics (OR 3.83; p < 0.001), fever (OR 3.27; p < 0.01), increasing age (OR 2.58; p < 0.005), and increased sputum volume (OR 1.94; p < 0.05). In contrast, the presence of rhinorrhea and muscle pain were protective factors (OR 0.23; p < 0.001 and OR 0.35; p < 0.05, respectively). The presence of purulent sputum and breathlessness was associated with a higher likelihood of antibiotic prescribing, although these associations were not statistically significant (ORs of 2.02 and 1.87, respectively). Table 5 presents the factors associated with theoretically inappropriate antibiotic prescribing for RTIs with clear diagnoses among residents. Initiation of the antibiotic course outside the nursing home was significantly associated with a reduced likelihood of inappropriate antibiotic use (OR 0.26; p < 0.001). Hosmer–Lemeshow goodness-of-fit and collinearity were assessed in both tables, showing adequate model fit and no evidence of collinearity (Hosmer–Lemeshow p > 0.3 and all variance inflation factors <5).

TABLE 4

CriteriaOR [CI 95%]P value
Sex
 Male1
 Female0.83 [0.47–1.44]0.514
Age, years
 ≤801
 >802.58 [1.42–4.75]0.002
Prior symptom duration, days
 ≤21
 >21.49 [0.83–2.72]0.188
Antibiotic taken during the previous 15 days
 No1
 Yes0.54 [0.28–1.07]0.074
Perception of antibiotic demand
 No1
 Yes3.83 [2.15–7.12]<0.001
Fever
 No1
 Yes3.27 [1.48–7.89]0.005
Shaking chills
 No1
 Yes1.65 [0.72–4.08]0.254
Confusion
 No1
 Yes4.72 [1.75–16.55]0.005
Joint and muscle pains
 No1
 Yes0.35 [0.15–0.86]0.020
Cough
 No1
 Yes1.17 [0.64–2.14]0.616
Rhinorrhea
 No1
 Yes0.23 [0.12–0.41]<0.001
Odynophagia
 No1
 Yes1.71 [0.76–4.10]0.211
Dyspnea
 No1
 Yes1.87 [0.98–3.69]0.065
Increase in sputum volume
 No1
 Yes1.94 [1.07–3.57]0.030
Purulent sputum
 No1
Yes2.02 [0.78–5.97]0.169
Bronchospasm
 No1
 Yes1.48 [0.54–4.83]0.476

Predictive factors for the administration of antibiotics for residents with respiratory tract infectionsa.

CI, confidence interval; OR, odds ratio.

a

Otorrhea, tonsillar exudate, and tender cervical glands have been excluded due to the low number of observations.

TABLE 5

CriteriaOR [CI 95%]P value
Age, years
 ≤801
 >800.98 [0.50–1.87]0.946
Sex
 Man1
 Woman1.21 [0.72–2.03]0.475
Prior symptom duration, days
 ≤21
 >21.26 [0.76–2.13]0.372
Antibiotic taken during the previous 15 days
 No1
 Yes1.09 [0.58–2.10]0.796
Perception of antibiotic demand
 No1
 Yes0.67 [0.41–1.09]0.108
Where the antibiotic course was initiated
 Nursing home1
 Other healthcare facility0.26 [0.13–0.48]<0.001

Risk factors associated with inappropriate antibiotic prescribing for respiratory tract infectiona.

CI, confidence interval; OR, odds ratio.

a

Based on 328 antibiotic prescriptions for respiratory tract infections with a clear diagnosis.

Discussion

This study highlights that 77.5% of RTI cases were treated with antibiotics, including a high proportion of infections typically considered viral in origin. In addition, antibiotics were also frequently prescribed for conditions that often resolve spontaneously without antimicrobial treatment. Another key finding is that more than 60% of antibiotic prescriptions were unnecessary based on clinical guidelines. Furthermore, the presence of certain clinical criteria increases the likelihood of both antibiotic prescribing, such as confusion, fever, and perceived demand for antibiotics. These findings highlight substantial room for improvement in antibiotic stewardship and offer insights into potential strategies to reduce inappropriate antibiotic use in nursing home settings.

More than three-quarters of all RTI cases in our study were treated with antibiotics. While antibiotics are warranted for residents with potentially serious infections such as pneumonia (), growing evidence suggests that most RTIs, even in older adults, are self-limiting and do not benefit from antibiotic treatment. In fact, in many cases, antibiotic use in this population may cause more harm than good (). Clinical guidelines clearly advise against the use of antibiotics for viral infections such as influenza, the common cold, COVID-19, or acute bronchitis (; ). Despite this, in our study, over 90% of acute bronchitis episodes were treated with antibiotics. Similarly, antibiotics are generally not indicated for other common self-limiting conditions such as acute rhinosinusitis, acute otitis media, or pharyngotonsillitis—unless a streptococcal infection is confirmed via a rapid antigen test, which is uncommon in older adults. Previous investigations in nursing homes have found that antibiotic prescribing was considered appropriate in only 42%–64% of cases (; ; ; ). The results of this observational study show a high rate of unnecessary antibiotic use, though it remains within the range reported in earlier studies.

The fact that the most predictive factor for unnecessary antibiotic use was initiation within the nursing home is particularly concerning. It suggests that processes and decision-making that occur on site—rather than in hospitals or outpatient clinics—materially increase the risk of inappropriate treatment. Several mechanisms may explain this association (). First, diagnostic uncertainty is common in nursing home residents (atypical presentations, limited access to imaging and lab tests), and this uncertainty frequently drives empiric prescribing. Evidence shows that routine testing and treatment of nonspecific symptoms are important sources of unnecessary UTI prescribing in care homes. Second, nursing staff critically influence the initiation pathway: nurses and nursing aides are frontline in assessing subtle changes, communicating with prescribers (often by phone), and recommending testing or treatment; their perceptions, anxiety about clinical deterioration, and patterns of communication with physicians strongly affect antibiotic starts. Third, compared with other settings there is wide variation in prescribing thresholds and fewer immediate diagnostic supports (e.g., onsite CRP, chest X-ray), so clinicians may adopt a lower threshold to start antibiotics “to be safe.” The results of our study clearly show a very limited use of rapid tests, with COVID-19 tests being the most frequently used, but in only one-quarter of cases. In most instances, other rapid tests, such as those for influenza or CRP, are not available in this setting. Finally, organizational factors, such as staffing levels, physician visit patterns, local culture, and incentives, create heterogeneity between facilities and can perpetuate routine unnecessary prescribing (). This finding emphasizes the need for antimicrobial stewardship interventions to be specifically tailored to the practices and needs of nursing home staff.

One major driver of antibiotic overprescription is the difficulty of distinguishing viral from bacterial infections based on clinical criteria alone, and this is aggravated by the lack of rapid diagnostic tests in this setting, as observed in this study. Only two conditions—COPD exacerbations and acute tonsillitis—have well-established clinical predictors that reliably indicate when antibiotics are warranted (; ). Prior research shows that clinicians often rely on specific findings in suspected acute tonsillitis, such as tonsillar exudate, to guide treatment decisions (). However, in our study the number of pharyngitis or tonsillitis cases was very low, limiting our ability to assess how such clinical features influenced prescribing in this setting. Several studies have shown that sputum-related findings—particularly increased volume and purulence—predict antibiotic prescribing (; ), a pattern also observed in our study. Although purulent sputum may suggest bacterial infection in COPD exacerbations, it is an unreliable indicator in acute bronchitis, which was markedly more common in our population. Evidence has long demonstrated that antibiotics offer no benefit over placebo for acute bronchitis, even when sputum is purulent (; ). For COPD exacerbations, a bacterial origin is only likely when at least two Anthonisen criteria are present (increased dyspnea, sputum volume, and sputum purulence), and only then are antibiotics recommended. Despite this, empirical prescribing remains widespread in Spain; one survey reported antibiotics in 90% of COPD exacerbations (), slightly higher than in our study, possibly because chronic bronchitis exacerbations were included in the same category. Notably, dyspnea was not associated with antibiotic prescribing in our data. Fever also strongly influenced prescribing. While it supports bacterial etiology in pharyngotonsillitis, its interpretation in lower RTIs is often mistaken. Although commonly linked to pneumonia, fever occurs across many RTIs and is not a criterion for antibiotic treatment in COPD exacerbations. Once pneumonia is excluded, high fever may even suggest viral infection (). Confusion was another factor associated with antibiotic use in our study, consistent with previous findings, particularly among residents with dementia (). These patients are also more likely to receive broad-spectrum agents such as quinolones compared with residents without cognitive impairment. Previous studies in our country have also demonstrated this association (; ). Clinicians are more likely to prescribe antibiotics when they perceive that patients or relatives expect them, even without an explicit request. Often, simply sensing that antibiotics are desired can influence prescribing decisions (). Patients frequently hold misconceptions about the benefits of antibiotics for RTIs, commonly believing they lead to faster recovery ().

This study has several limitations that warrant consideration. Although nursing home staff primarily comprises nurses, the authority to prescribe antibiotics resides with physicians. In the Spanish context, however, physicians in nursing homes are typically external consultants who are not present during nights or weekends, whereas nursing staff are continuously available. This organizational structure may influence prescribing practices. Furthermore, the data collection template did not include information on residents’ comorbidities, despite the fact that underlying chronic conditions can significantly influence clinical decision-making and antibiotic prescribing in older adults. This limitation may have prevented us from fully capturing important factors that contribute to treatment choices in this population. Nonetheless, the large sample size in this study likely mitigates the risk of significant bias arising from this omission. Similarly, while not all signs and symptoms of RTIs were captured, owing to the pragmatic constraints of conducting such a study in routine clinical settings, the registry still included 88 variables. Another notable limitation is the absence of clinical outcome measures. However, the registration forms did include data on hospital referrals, offering a partial proxy for clinical impact. Additionally, the process of self-registration may have influenced prescribing behavior. While treatment decisions should ideally follow diagnostic assessment, in routine clinical practice these processes are frequently intertwined. As previously noted in other studies (; ), decisions regarding antibiotic therapy may be made concurrently with, or even prior to, the establishment of a formal diagnosis. It cannot be guaranteed that all nursing home staff collected data consistently over the full three-month period; however, this limitation is not expected to have affected the overall results of the study. Despite these limitations, the data collection process was designed to be minimally disruptive. The registration forms required staff only to check pre-defined criteria, without the need for narrative input, thereby allowing participating nurses to maintain their usual workflows during the study period.

This cross-sectional study provides valuable insights into antibiotic use for RTIs within the real-world context of nursing homes. The findings highlight the persistent issue of antibiotic overprescribing, with only slightly more than one-third of prescriptions deemed appropriate. The fact that treatments initiated in nursing home settings are more frequently unnecessary makes the implementation of antimicrobial stewardship interventions in this setting essential. The implementation of antimicrobial stewardship programs in this setting has been shown to effectively reduce inappropriate antibiotic use (); however, a recent narrative review revealed that the impact of such programs varies considerably across long-term care facilities (). In most cases, the decision to prescribe antibiotics is based solely on clinical criteria, as rapid diagnostic tests are either not routinely employed or are not readily accessible. Evidence suggests that improving access to these tests in nursing homes could help reduce unnecessary antibiotic prescribing (). Furthermore, studies from other settings have demonstrated that rapid tests can be helpful in managing patient expectations, especially when patients or their relatives request antibiotics. In this context, our results may also support efforts to educate and reassure residents and their families when antibiotics are not clinically indicated.

In conclusion, the findings of this study open new avenues for the development and implementation of targeted strategies to promote more rational antibiotic use in nursing homes. These may include incorporating simple decision-support tools tailored to the needs of nursing home staff, expanding access to rapid diagnostic tests to support more accurate clinical decision-making, and providing targeted training for personnel involved in assessing RTIs. Together, such measures could help translate our findings into practical improvements in antimicrobial stewardship within this care setting.

Statements

Data availability statement

The raw data supporting the conclusions of this article will be made available by the authors, without undue reservation.

Ethics statement

The studies involving humans were approved by Ethics Committee Board of the Primary Care Research Institute IDIAP Jordi Gol, Barcelona, Spain (reference number 22/119-P). The studies were conducted in accordance with the local legislation and institutional requirements. Written informed consent for participation in this study was provided by the participants’ legal guardians/next of kin.

Author contributions

CL: Project administration, Investigation, Validation, Methodology, Writing – review and editing, Funding acquisition, Writing – original draft, Visualization, Conceptualization. RMr: Visualization, Conceptualization, Validation, Resources, Writing – review and editing, Investigation, Supervision. JM-N: Writing – review and editing, Investigation, Methodology. CZ: Investigation, Writing – review and editing, Methodology. MV: Methodology, Writing – review and editing, Investigation. CR: Methodology, Investigation, Writing – review and editing. CS: Writing – review and editing, Methodology, Investigation. RMg: Writing – review and editing, Investigation, Methodology. PM: Methodology, Investigation, Writing – review and editing. AN: Writing – review and editing, Investigation, Methodology. EL: Writing – review and editing, Investigation. AG-S: Methodology, Investigation, Conceptualization, Writing – review and editing, Project administration. RMn: Validation, Methodology, Data curation, Formal Analysis, Writing – review and editing, Supervision, Conceptualization, Investigation, Software, Resources.

Funding

The author(s) declared that financial support was received for this work and/or its publication. This work was supported by the Pfizer inc. managed by Global Medical Grants & Global Bridges Mayo Clinic Quality Improvement, grant ID 71388143. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript; or in the decision to publish the results.

Acknowledgments

The authors would like to thank all participants who have voluntarily implemented the audit registrations.

Conflict of interest

The author(s) declared that this work was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Generative AI statement

The author(s) declared that generative AI was not used in the creation of this manuscript.

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Publisher’s note

All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.

References

Summary

Keywords

anti-bacterial agents, antimicrobial stewardship, elderly, medical audit, nursing homes, respiratory tract infections

Citation

Llor C, Morros R, Mateos-Nozal J, Zárate Sáez CM, Vaquero Pinto MN, Rodríguez Jiménez C, Sáez Bejar C, Magallón-Botaya R, Matovelle P, Navarro Sanmartín A, López Pérez E, García-Sangenís A and Monfà R (2026) Antibiotic use for respiratory tract infections in nursing homes: a multicentre cross-sectional study. Front. Pharmacol. 16:1721689. doi: 10.3389/fphar.2025.1721689

Received

09 October 2025

Revised

28 November 2025

Accepted

15 December 2025

Published

05 January 2026

Volume

16 - 2025

Edited by

Ranjan K. Mohapatra, Government College of Engineering, Keonjhar, India

Reviewed by

Enoc Isaí Hernández Cantú, Mexican Social Security Institute, Mexico

Raluca Enache, Sensorium ORL Center, Romania

Updates

Copyright

*Correspondence: Carl Llor,

Disclaimer

All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.

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