The clinical relevance of pathogen Aerococcus urinae identification by MALDI-TOF mass spectrometry: a case of sepsis in 86-year-old Caucasian male

The infrequency of urinary tract and blood stream infections caused by Aerococcus urinae is most probably due to the difficulties in the identification of this bacterium using standard microbiological methods. With the introduction of more sensitive and accurate techniques in clinical microbiology, such as genetic approaches and Matrix-Assisted Laser Desorption/Ionization-Time Of Flight (MALDI-TOF) mass spectrometry (MS), the incidence of infections due to A. urinae increased. Herein, we described a case of urinary tract and bloodstream infection caused by A. urinae, which occurred in an 86-year-old Caucasian man with a previous history of prostate cancer. The identification of A. urinae was performed by MALDI-TOF MS, since this microorganism cannot be identified by biochemical reactions. In this report, we highlight the need to consider MALDI-TOF MS as technique of choice for A. urinae identification in the presence of subjects with predisposing factors, such as old age, male gender, and genitourinary tract pathologies.