Aerococcus urinae, Aerococcus viridans, Aerococcus sanguinicola
Aerococcus genus, a firmicute, was first identified in 1953 [Williams, 1953]. Multiple species have been identified since then; not all of them are human pathogens.
Aerococcus is a gram-positive coccus in clusters (like Staphylococcus), alpha-hemolytic on blood agar and catalase-negative (like Streptococcus).
Identification can be made using automated systems API, 16S rDNA sequence analysis or MALDI ToF. Automated systems may not have all the species in the database.
A urinae is known to cause
UTI in elderly (median age 75 y; F>M) people with comorbidities (Diabetes Mellitus, malignancy, prostatitis, indwelling catheter etc)
bacteraemia (mostly as a complication of UTI),
endocarditis (a complication of bacteraemia – 1/3rd of bacteraemia cases; poor prognosis)
and rarely other infection (see chart above).
The prevalence of these bacteria in the urine is 0.3-4%.
A urinae is often seen in mixed-blood culture with – St aureus, E coli, Actinobaculum schaalii.