Epidemiology and urological pathogenic potential of Aerococcus species in greater Glasgow and Clyde (Descriptive study of Aerococcus urinae in blood culture and urinary samples: clinical importance and potential marker of urinary tract pathology)

Introduction. Aerococcus species in particular A. urinae are increasingly reported as causative agents of bacteraemia, urinary tract infection, sepsis, and endocarditis. We sought to establish the epidemiology of A. urinae in Glasgow hospitals and whether the presence of the organism in clinical isolates could be an indicator of undiagnosed urinary tract pathology.

Hypothesis/Gap statement. The knowledge gap among clinical staffs on Aerococcus species as emerging pathogens can be filled by understanding its epidemiology and clinical importance.

Aim. Describe the epidemiology and clinical importance of Aerococcus urinae .

Methodology. We reviewed positive blood cultures with Aerococcus species (2017–2021) and urinary isolates (2021) in Glasgow hospitals. Data were collected from clinical and laboratory database systems.

Results. All 22 positive blood cultures were A. urinae and sensitive to amoxicillin, vancomycin, and ciprofloxacin. The median age was 80.5; the majority was male (18). In total, 15/22 (68 %) were diagnosed with urinary tract infection. Thirteen were treated with amoxicillin. No cases of infective endocarditis were noted. One patient was subsequently diagnosed with bladder carcinoma. All 83 positive urinary isolates in 72 patients were A. urinae . One was resistant to amoxicillin; two to ciprofloxacin; all sensitive to nitrofurantoin and vancomycin. The majority was female (43/83), the median age was 80. The commonest risk factors were underlying malignancy including bladder cancer (5/18), chronic kidney disease (17) and diabetes (16). Clinical data was unavailable in 24 episodes. Of these, 41/59 (69.5 %) were diagnosed with urinary tract infection. One patient was subsequently diagnosed with metastatic renal cancer while bladder wall lesions were identified in three patients, two of whom were waiting for an urology review at the time of study. Thirteen patients (18 %) had 1 year recurrent bacteriuria and three were not treated on initial episode.

Conclusion. A. urinae are emerging pathogens and are likely to become more common due to advances in laboratory technologies and an ageing population. Clinical teams should be aware of their urological pathogenic potential and not dismiss them as contaminants. Whether Aerococcus infection is a potential indicator for undiagnosed urinary tract malignancy warrants further studies.