Etiology and the challenge of diagnostic testing of community-acquired pneumonia in children and adolescents

Abstract

Background Pneumonia is the leading cause of mortality in pediatric population. The etiology of pneumonia in this population is variable and changes according to age and disease severity and where the study is conducted. Our aim was to determine the etiology of community-acquired pneumonia (CAP) in children aged 1 month to 17 years admitted to 13 Colombian hospitals. Methods Prospective cohort study. Hospitalized children with radiologically confirmed CAP and ≤ 15 days of symptoms were included and followed together with a control group. Induced sputum (IS) was submitted for stains and cultures for pyogenic bacteria and Mycobacterium tuberculosis, and multiplex PCR (mPCR) for bacteria and viruses; urinary antigens for pneumococcus and Legionella pneumophila; nasopharyngeal swabs for viruses, and paired serology for atypical bacteria and viruses. Additional cultures were taken at the discretion of primary care pediatricians. Results Among 525 children with CAP, 71.6% had non-severe pneumonia; 24.8% severe and 3.6% very severe pneumonia, and no fatal cases. At least one microorganism was identified in 84% of children and 61% were of mixed etiology; 72% had at least one respiratory virus, 28% pyogenic bacteria and 21% atypical bacteria. Respiratory syncytial virus, Parainfluenza, Rhinovirus, Influenza, Mycoplasma pneumoniae, Adenovirus and Streptococcus pneumoniae were the most common etiologies of CAP. Respiratory syncytial virus was more frequent in children under 2 years and in severe pneumonia. Tuberculosis was diagnosed in 2.3% of children. IS was the most useful specimen to identify the etiology (33.6%), and blood cultures were positive in 3.6%. The concordance between all available diagnostic tests was low. A high percentage of healthy children were colonized by S. pneumoniae and Haemophilus influenzae, or were infected by Parainfluenza, Rhinovirus, Influenza and Adenovirus. Conclusions Respiratory viruses are the most frequent etiology of CAP in children and adolescents, in particular in those under 5 years. This study shows the challenges in making an etiologic diagnosis of CAP in pediatric population because of the poor concordance between tests and the high percentage of multiple microorganisms in healthy children. IS is useful for CAP diagnosis in pediatric population.

Nasopharyngeal aspirates in children with severe community-acquired pneumonia collected within 3 days before bronchoscopy can partially reflect the pathogens in bronchoalveolar lavage fluids

“…Respiratory viruses are frequently detected in community-acquired pneumonia (CAP) among children of all ages globally [16][17][18]. The majority of pathogens associated with hospitalized SCAP in children were viruses in this study, which were consistent with the finding in this field over the past decade in high disease burden low and middle income countries (LMICs) as well as in Europe and the USA [11,16,[19][20][21][22][23]. In this study, seven common respiratory viruses were found in 32.3% (66/204) of the BALFs tested by DFA, and such results were consistent Fig.…”

“…Second, we did not use more sensitive molecular biological diagnostic methods, which might lead to low detention rates of pathogens [ 18 , 31 , 32 ]. Third, the human rhinovirus (HRV) was not studied which has become identified as a more prominent lower airway pathogen than previously suspected [ 5 , 7 , 9 , 16 , 17 , 19 , 21 , 28 , 30 ]. We still believed that our study had unique significances, given that the DFA method was based on the existent of viruses antigens judged by naked eyes with fluorescence microscope, and the routine bacterial culture, which are the two classical methods for pathogens detection.…”

The Etiology of Community-Acquired Pneumonia Correlates with Serum Inflammatory Markers in Children

“…One of the most challenging issues in the field of pediatrics is etiology confirmation in patients with pneumonia; the problem with various diagnostic strategies and possibilities remains to be solved, since eagerness to find etiological factor, on the one hand, is balanced by a tendency towards the least invasive diagnostic methods in children, on the other hand. Moreover, while the lack of confirmation of any particular etiological agent does not exclude its presence, a high percentage of multiple microorganisms might also be observed in healthy children, and a differentiation between infection and colonization needs to be considered [ 41 ]. A strong emphasis needs to be placed on the age-related variations in the frequency of the particular etiological agents.…”

Novel care pathway to optimise antimicrobial prescribing for uncomplicated community-acquired pneumonia: study protocol for a prospective before–after cohort study in the emergency department of a tertiary care Canadian children’s hospital

“… 32 Furthermore, a recent prospective cohort study of children hospitalised with CAP in Colombia (where pneumococcal vaccination rates are low) showed that only 18% had a positive UAg result (as compared with 8% of controls). 33 UAg is modestly useful in the evaluation of adults with CAP and has been recommended to improve antimicrobial stewardship. 34 35 In a recent small prospective cohort of children hospitalised with respiratory infection at our institution, we found that UAg testing was moderately specific for probable bacterial CAP.…”

“…Urinary pneumococcal antigen (UAg) testing was previously not specific for pneumococcal disease in children31; however, this may no longer be true in the post-13-valent pneumococcal conjugate vaccine (PCV13) era with changes in S. pneumoniae colonisation patterns 32. Furthermore, a recent prospective cohort study of children hospitalised with CAP in Colombia (where pneumococcal vaccination rates are low) showed that only 18% had a positive UAg result (as compared with 8% of controls) 33. UAg is modestly useful in the evaluation of adults with CAP and has been recommended to improve antimicrobial stewardship 34 35.…”