Most clinical guidelines recommend antibiotic prescribing for patients with sore throat when the infection is severe and in patients with group A β-haemolytic streptococcus (GABHS) infection.1 However, identifying patients with GABHS only on clinical grounds is difficult. Most countries recommend the use of rapid antigen detection tests (RADT) in patients with suspected streptococcal infections as this practice has been associated with a reduction of inappropriate use of antibiotics.2 Spanish guidelines recommend these tests to be performed specifically in patients with at least two Centor criteria—history of fever, tender cervical nodes, pharyngeal exudates and/or absence of cough.3 When it comes to lower respiratory tract infections (LRTI), systematic reviews have suggested that antibiotics do not make any difference in the course of influenza and modify the course of acute bronchitis only marginally.4,5 However, they are recommended in acute exacerbations of chronic obstructive pulmonary disease (COPD), mainly when purulent sputum is present and in all cases of pneumonia.5 Identifying patients with pneumonia has also shown to be challenging in primary care when it is only based on symptoms, signs and examination.6 Used as an adjunct to clinical examinations by general practitioners (GPs) the C-reactive protein (CRP) rapid test has also shown to reduce antibiotic use in these infections.7

Despite the compelling evidence about the benefits of having these rapid tests in primary care, their availability in Spanish surgeries is scarce. However, GPs in our country prescribe antibiotics in over 60% of cases of acute pharyngitis and acute bronchitis.8 Inappropriate antibiotic use has adverse medical consequences and contributes to microbial antibiotic resistance.9 We carried out a European-funded study aimed at promoting the rational use of antibiotics. In 2015 we selected a sample of GPs who had never used rapid tests in their consultations and compared the use of antibiotics with the current clinical guidelines estimating the number of antibiotics that could have been saved if GPs had appropriately used these tests and had followed the guidelines properly.

National coordinators from each of the eight participating Autonomous Communities invited local GPs to participate. They were requested to register individuals aged 14 or older with acute pharyngitis (including acute tonsillitis) and LRTIs over a 3-week period from January to March 2015 by means of a 47-item chart providing relevant information about the infectious disease. On this sheet, the physician attending the patient noted different specific parameters of medical care, including the age and gender of the patient, the number of days with symptoms, presenting signs such as fever, cough, odynophagia, pharyngeal exudates, presence of tender cervical nodes, dyspnoea, increase in sputum volume and purulence of sputum, diagnosis (pharyngitis, acute bronchitis, influenza, acute exacerbation of chronic bronchitis or COPD, pneumonia), infection severity on a 5-item scale, performance of chest radiograph, pulse oximetry, rapid antigen detection tests and CRP rapid tests, antibiotic treatment or not, allergy or not to penicillin, whether the patient requested an antibiotic, significant comorbidities and referral to another healthcare setting.

This information was compared to the recent Spanish guidelines in the case of pharyngitis3 (Figure 1a). Although our guidelines on LRTIs recommend the utilisation of CRP their use is negligible in Spain. Thus, algorithms provided in the current guidelines describe the usual practice of undertaking a thorough physical examination asking GPs to request radiological study when the suspicion of pneumonia is very likely. Therefore, we used the recent Dutch guidelines as the comparator for this study classifying patients into three different severity groups, considering the use of CRP only when there was an intermediate risk (Figure 1b).10

Figure 1.

Recommended management of both infections. (a) Acute pharyngitis. (b) Lower respiratory tract infection.

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The main conclusion of this study is that up to 84.5% of the antibiotics given to patients with pharyngitis and 69.8% given to LRTI patients can have been saved with the proper use of rapid tests. However, the participating GPs had seldom or never used either of the two rapid tests mentioned in this study and had not previously participated in any other study on the rational use of antibiotics. One of the limitations of the present study is that GPs participated on a voluntary basis and their prescribing habits may not represent the average use of antibiotics in our country.11 GPs who are more interested in research prescribe more appropriately than GPs in general, and this fact can explain why the antibiotic prescribing rate observed in the present study was slightly lower than 50% in both infections. A registration such as that used in our study might not have contained all the variables needed for making a therapeutic decision, but the most important variables were included, and the information provided was sufficient for further comparison with the clinical guidelines. The strength of our study is its large sample size with detailed documented consultations, enabling us to compare this information with that provided in the guideline recommendations.

The costs related to the antibiotics saved were not calculated in this study. Neither did we consider the costs of the rapid tests, days off work and visits to the healthcare services. Another limitation of the study is the fact that we considered a hypothetical situation of having access to point-of-care tests and these tests had been appropriately used by GPs who had followed the existing guidelines. However, evidence clearly states that guidelines adherence by GPs in respiratory tract infections is not optimal, either in terms of when antibiotics are indicated or with the usage of first-line antibiotics.12,13 In the present study, the types of antibiotics prescribed reflect that guidelines are scarcely used in our country since penicillin, which is considered the first-choice drug for GABHS infection, was the third antibiotic most frequently given to patients with acute pharyngitis whereas amoxicillin and clavulanic acid were the most commonly used in LRTI, when they are only recommended as first-choice drugs in acute exacerbations of COPD but not in other respiratory tract infections. Oddly enough, macrolides accounted for 22% of the antibiotics prescribed in patients with LRTI, and amoxicillin, considered as the first-line antibiotic in most of the LRTIs ranked fourth in our study.

According to the current clinical guidelines RADT should have been used in 37.8% of the episodes of acute pharyngitis and CRP concentrations should have been determined in 31.2% of the LRTIs. Antibiotics should have only been prescribed with positive RADT results and with CRP levels greater than 50mg/L as well as in all severe patients. Likewise, antibiotics should have been withheld in patients with less than two Centor criteria, in all the uncomplicated LRTIs and in the cases with CRP levels less than 20mg/L. Taking all these requisites into account the saving of antibiotics would have been considerable; however, both the utilisation of rapid tests in the countries where these tests have widely been used over the last years and the no utilisation of antibiotics in case of negative results are far from being optimal.14 Notwithstanding, considering the weaknesses of the study and their inference insight this paper shows that the correct introduction of rapid tests in clinical practice in Spain could result in a considerable saving of unnecessary antibiotic prescribing.

Study funded by TRACE (Translational Research on Antimicrobial resistance and Community-acquired infections in Europe).

CL reports having a grant from the Fundació Jordi Gol i Gurina for a research stage at the University of Cardiff. He also reports receiving research grants from the European Commission (Sixth & Seventh Programme Frameworks and Horizon 2020), Catalan Society of Family Medicine, and Instituto de Salud Carlos III. The other authors have nothing to declare.