Blood: Aggregatibacter actinomycetencomitans – Shipped May 14, 2018
A simulated blood culture sample collected from 56 male with heart murmur was sent to category A laboratories.
Participants were expected to isolate, identify, and report Aggregatibacter actinomycetemcomitans.
MAIN EDUCATIONAL POINTS from M181-4
- HACEK group genera should be considered when patients present with presumptive infectious endocarditis, the blood culture may require 3 -4 days of incubation (although almost all isolates will grow with the usual 5 day incubation period of contemporary blood culture systems), and the Gram smear shows small gram negative coccobacillary morphotypes.
- Isolates of Aggregatibacter (formerly Actinobacillus) should be separated from other species of Haemophilus – antimicrobial treatment may be more prolonged. Most Haemophilus species grow more rapidly than Aggregatibacter and can be differentiated by their growth characteristics and colony morphology on enriched media.