Streptococcus

What does this bacterium look like?

This bacterium has the shape of small spheres and looks a bit like an open pearl necklace. Streptococcus are, depending on the exact species, between 0.5 to 2 micrometers in size (that’s small when you recall that 1000 micrometers fit into one millimeter). These bacteria often hang together in pairs or even in long strands.

What does science already know about this bacterium?

You may immediately think of negative stories when you hear the name of this bacterium, but that doesn’t have to be the case. There are indeed Streptococcus species that can make you very sick, but they are harmless on and in many parts of your body. In the lab of the University of Antwerp, for example, we are investigating the presence of Streptococcus salivarius in the upper respiratory tract, where they can even have a positive health effect, for example against chronic ear infections.

There are also Streptococcus-based probiotics, often containing Streptococcus thermophilus. Streptococcus thermophilus can also be found in almost all yogurts, where they are used as a starter culture to acidify and thicken milk. In Europe, manufacturers of live yoghurt ferments are allowed to use the health claim that Streptococcus thermophilus together with the other live yoghurt ferments can help with the digestion of lactose.

The genome size of this bacterium is around 2 million base pairs. So, they have an average of around 1900 genes and can produce a lot of molecules.

What is this bacterium doing in my vagina? 

The Streptococcus is a distant relative of the lactobacilli and can also produce lactic acid. Usually, the presence of this type of bacteria in your vagina does not cause any problem. One type of Streptococcus, Streptococcus agalactiae or the B variant, can cause problems when present in your vagina. Sometimes they cause bladder infections.

If you are pregnant, you will receive a standard test for this Group B Streptococcus or GBS in Belgium. If you test positive, you will be given preventive antibiotics during delivery. This is done, because this GBS bacterium is usually harmless for adult women, but in exceptional cases can be dangerous for the newborn baby.

Unfortunately, the technique used at Isala does not allow us to find out which Streptococcus species is in your vagina: a favourable or less favourable one. However, as we explained earlier, your vaginal microbiome is somewhat dynamic. It could well be that the Streptococcus dominance has already disappeared. In any case, the presence of this bacterium usually does not cause any complaints and you are perfectly healthy. The most important advice we can give you remains the same: do you experience complaints or are you worried about something? Contact your doctor. Within Isala, we even have a separate webpage with more background information especially for doctors, so you can certainly refer to that.

What is this bacterium doing in my mouth?

Streptococci often have special structures on their cell wall that allow them to easily adhere to different places in the mouth. While some species of Streptococcus can contribute to tooth decay, others play an important role in keeping acidity balanced.

What is this bacterium doing on my skin?

This genus of bacteria does appear in low numbers on your skin. At Isala, we found a bit more Streptococcus on the skin around the mouth. We can explain this by the contact with saliva, where we did find Streptococcus more often. Only a few species of this Streptococcus can cause infections. For example, group A Streptococcus (also known as GAS or “strep”) can infect your skin in addition to your throat, resulting in red and itchy sores also known as impetigo.