Clinical significance and antimicrobial susceptibilities of Aerococcus sanguinicola and Aerococcus urinae

A retrospective chart review was performed on 92 patients from whom 118 isolates of Aerococcus sanguinicola (n = 52) or Aerococcus urinae (n = 66) were obtained from urine cultures between October 2007 and June 2008 to assess clinical presentation and antimicrobial susceptibilities. The mean patient age was 82 (range 24-101) years. The majority was female (76% and 87% for A. sanguinicola and A. urinae, respectively) and institutionalized (61% and 60%, respectively). The majority of male patients had underlying prostatic disease (55% and 63%, respectively). Thirty-one of 46 patients with A. sanguinicola and 45 of 57 patients with A. urinae isolated from the urine had a clinical diagnosis of urinary tract infection. One subject had A. sanguinicola isolated from blood cultures. A. sanguinicola and A. urinae had low ceftriaxone, penicillin, and vancomycin MICs. MICs to erythromycin and levofloxacin were ≥0.5 and >4 μg/mL in 41% and 78% of A. sanguinicola and 17% and 23% of A. urinae isolates, respectively. In conclusion, A. sanguinicola and A. urinae are not infrequent causes of urinary tract infection and most A. sanguinicola isolates have elevated MICs to levofloxacin.