What are Respiratory Tract Infections?

Respiratory tract infections (RTIs) could be classified into two categories, based on the location of the infection: upper respiratory tract and lower respiratory tract.

Upper respiratory tract infections (URTIs) affect one or more anatomical regions: ears (otitis), sinuses (sinusitis), throat (angina), and nasopharynx (nasopharyngitis). The main viruses identified in these infections are Rhinoviruses, Coronaviruses, Respiratory Syncytial Viruses, Influenza Viruses, Parainfluenza Viruses, Adenoviruses, Cytomegaloviruses, Epstein Barr Viruses, and Herpes Simplex Viruses, Human Metapneumovirus, and Enteroviruses.

URTIs are very common and are usually caused by viruses that heal without antibiotic treatment. In this case, the antibiotics have no effect, are unnecessary, or even harmful. Treatment then relies on relieving the patient's symptoms.

However, it is recommended to prescribe an appropriate antibiotic in certain clinical situations suggesting a bacterial infection. This is the case of acute purulent otitis media, certain sinusitis, and certain tonsillitis such as, for example, streptococcal angina.

Potentially more severe than URTIs, lower respiratory tract infections (LRTIs) include acute bronchitis, pneumonia, exacerbation of chronic bronchitis, and bronchiolitis (in young children in general.)

Acute bronchitis is defined as acute inflammation of the bronchi and bronchioles. In the majority of cases it is caused by respiratory viruses including Influenza, Parainfluenza, Adenoviruses, and Respiratory Syncytial Viruses. 

Pneumonia is an infection of the lung parenchyma. In community-acquired pneumonia (CAP), bacteria are mainly identified as the source. Streptococcus pneumoniae and Haemophilus influenzae are at the top of the list and atypical bacteria can also be found. These bacteria are frequently associated with secondary infections following a viral respiratory infection.

First-line antibiotics are often effective in treating patients with exacerbated chronic bronchitis or pneumonia, the underlying cause is usually bacterial. However, antibiotics are not effective for lower respiratory tract infections caused by a virus.

Upper respiratory tract infections are the leading cause of disease incidence worldwide. In 2019, 17.2 million episodes occurred, representing more than 2.25 episodes per individual per year (even 3 in children). They are associated with a significant socio-economic burden: it is a major cause of consultation with general practitioners and a major cause of sick leave.¹

Despite a decrease in mortality, lower respiratory tract infections are the leading cause of death from infectious disease.²

Taken as a whole, respiratory diseases are responsible for 2.377 million deaths worldwide each year. In industrialized countries, respiratory infections are the main cause of pediatric consultation, are also involved in healthcare-associated infections (HAI), and epidemics.²

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Although very frequent, RTIs remain a challenge for clinicians as they have various clinical presentations / severities and are caused by numerous microbiological agents (bacteria, virus, fungus, parasite). 

The clinical assessment is frequently not sufficient to predict the etiological agent, for LRTI. Timely and accurate diagnosis is critical to select the appropriate therapy.

Upper and lower RTI can be caused by different pathogens. The sample types used to detect these pathogens are different: Upper respiratory tract pathogens (viral and bacterial) are found in nasal, nasopharyngeal and throat specimens and lower respiratory tract pathogens are found in sputum and bronchoalveolar lavage specimens. bioMérieux has solutions to address the 2 types of RTIs and the many infectious agents that cause those infections. 

Identification of the pathogen(s) and accuracy of the diagnosis is critical. Many of the pathogens responsible for RTIs are fastidious and require specific conditions for growth. The Targeted Treatment Regimen (TTR) could elucidate the reasons behind the limited prescription rates. The syndromic approach marks a significant breakthrough in improving patient care and facilitating appropriate antibiotic treatments. Conventional microbiology continues to play a crucial role in optimizing therapy and monitoring resistance over time.

As a leader in infectious disease diagnostics, you can count on bioMérieux to deliver the products you need to support RTI diagnostics from sample collection to guided therapy to antibiotic discontinuation. Our respiratory tract infection offer is reinforced by our promise to be a committed service partner for all our products from consultancy to installation, connectivity, training, verification, and customer service to help our customers achieve optimized time to therapy for better patient care and to fight AMR.