Microbiological testing of adults hospitalised with community-acquired pneumonia: an international study

Carugati, Manuela; Aliberti, Stefano; Reyes, Luis Felipe; Franco Sadud, Ricardo; Irfan, Muhammad; Prat, Cristina; Soni, Nilam J.; Faverio, Paola; Gori, Andrea; Blasi, Francesco; Restrepo, Marcos I.

Among 3702 patients, 3217 (86.9%) had at least one diagnostic test performed, with 1173 (36.5%) patients with at least one pathogen detected by diagnostic testing. Variables significantly associated with the performance of diagnostic testing are presented in table 2. When patients from whom at least one pathogen was detected were compared with patients from whom no pathogens were detected, we found the former group more commonly presented the following conditions: bronchiectasis, tracheostomy, at least one respiratory comorbidity, hypertension, HIV infection, pervious infections, previous healthcare exposure, severe CAP, ICU admission, mechanical ventilation and use of vasopressors (table 2) . Oceania, and in 1.3% of patients admitted to African hospitals ( p<0.01). Pneumococcal and Legionella urinary antigen tests were performed in >40% of the patients admitted in European hospitals and in <20% of the patients hospitalised in the remaining continents ( p<0.01). Acute-phase serology for Chlamydophila pneumoniae, Mycoplasma pneumoniae and Legionella species was more common in Europe (11.2%) than elsewhere (4.6%) ( p<0.01). Diagnostic testing was concordant with the IDSA/ATS and ERS recommendations in 16.7% and 23.9% of the patients, respectively. When the overall study population was analysed, over-testing and under-testing were reported in 59.3% and 19.1% of the IDSA/ATS-discordant patients, respectively (figure 1). Among IDSA/ATS-discordant patients, blood cultures performed without indications accounted for the majority of over-testing, while the lack of pneumococcal urinary antigen test was responsible for a significant percentage of under-testing. Over-testing and under-testing were documented in 29.3% and in 42.0% of the ERS-discordant patients, respectively (figure 1). Among ERS-discordant patients, pneumococcal and Legionella urinary antigen tests performed without an indication accounted for the majority of over-testing, while under-testing was mainly due to the lack of obtaining blood cultures when indicated. IDSA/ATS concordance was more common in Europe than in North America (21.5% versus 9.8%; p<0.01), while ERS concordance was more common in North America than in Europe (33.5% versus 19.5%; p<0.01).