Streptococcus agalactiae

sector Strep (streptococci), small bright green - blue colonies, marked with the number 10.
Streptococcus agalactiae ClearMilk Test

Streptococcus agalactiae ranks among the so called infectious causal agents of mastitis in cattle. It is well adapted to the mammary gland and has affinity for milk. It does not multiply in the environment but is able to persist there for several weeks.  

The infected mammary gland of the cow, other animals, humans, contaminated environment are sources of the infection. Mildly infected cows in the herd are the constant source of the infection because they excrete bacteria irregularly and they may not be detected during the microbiological examination. In practice this means that each dairy cow coming from a farm where S. agalactiae is present is suspected of being affected.

Clinical signs of mastitis caused by S. agalactiae are varied; latent and subclinical forms often develop into acute catarrhal mastitis after calving.

At the ClearMilk test, Streptococcus agalactiae grows in small colonies of blue-green colour by 24 hours after putting milk into a Petri dish. Then, confirmation in our laboratory at the MALDI TOF machine and especially determination of antibiotic susceptibility is possible. From the good practice on the antibiotic therapy point of view and with respect to the development of resistance we choose narrow-spectrum antibiotics, e. g. benzylpenicillin, according to the result of the antibiogram.