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.

Thirdly, our study confirmed the differing diagnostic yield of various diagnostic tests. Specifically, only 6.7% of blood cultures yielded a positive result, confirming the low sensitivity of blood cultures for revealing the aetiology of CAP, similar to the findings of other studies [16] [17] [18] [19] [20] [21] [22] [23] . In contrast, BAL cultures were characterised by a high diagnostic yield (38.8%). While impractical and potentially associated with complications, BAL cultures represent an effective diagnostic tool for patients with severe infections, who may benefit the most from a targeted antimicrobial regimen. Indeed, a randomised trial by VAN DER EERDEN et al. [24] showed a statistically significant difference in mortality among ICU patients receiving empirical broad-spectrum antimicrobials (91%) versus patients receiving pathogen-directed antimicrobials (45%). Fourthly, our analysis described a significant geographic variation in diagnostic testing strategies. We could speculate that the economical restraints of African health systems accounted for the reduced number of blood cultures and viral tests performed in this setting. Laboratory infrastructure to support diagnostic microbiological testing is limited in most African countries: bacteriological culture or molecular techniques that form the mainstay of CAP diagnostics in well-resourced settings are often lacking in Africa [25, 26] . In contrast, the seasonality and the epidemiological relevance of respiratory viruses, such as avian-origin influenza A and Middle East respiratory syndrome coronavirus, may have favoured the performance of viral testing in Asia [27, 28] .