Clinical spectrum of infections due to the newly described Actinomyces species A-turicensis, A-radingae, and A-europaeus

Over a 7-year period, we isolated 294 Actinomyces-like organisms (ALOs) whi ch were not clearly identifiable. Using well-defined probes coding for sequ ences specific for recently described Actinomyces species (A. turicensis, A . radingae, and A. europaeus), we were able to identify 128 strains. The ma jority belonged to the A. turicensis species. A. radingae was found only in patients with skin-related pathologies, A. europaeus was also detected in patients with urinary tract infections. The main sources of A. turicensis w ere genital infections, followed by skin-related and urinary tract infectio ns. Additional clinical pictures were appendicitis, cholecystitis, ear, nos e, and throat infections, and bacteremia, In a small number of patients the se ALOs were found as the only pathogen, Strains of the three species were tested by two widely used biochemical identification methods. A. turicensis was easily identifiable by both these methods. We conclude that these ALOs are not infrequent pathogens and are found in a wide range of human infect ions. At least A. turicensis is easily identifiable by clinical diagnostic laboratories.