(Have we had this thread before?)

https://www.theguardian.com/science/2021/mar/18/new-bacteria-lurking-on-iss-no-space-oddity-says-scientist

Four species of bacteria have been found on the ISS.
Three of them are new to science.

The new bacteria were identified from swabs of various locations inside the ISS. One was discovered on a dining table; another on an overhead panel in a research area used to study low gravity; the third in the Cupola observatory. The fourth species, which was already known of, was found on an old air-purifying filter, which had been returned to Earth. All of them are rod-shaped bacteria belonging to the Methylobacteriaceae family – usually found in soil and fresh water, where they help to promote plant growth and defend against pathogens.

Since these ISS strains were isolated at different time periods and from various locations, their persistence in the ISS environment and ecological significance in the closed systems warrant further study.

Methylorubrum rhodesianum was the bacterium found that was already known to science. The other three had never previously been identified, but genetic and taxonomic analysis suggests they are related to Methylobacterium indicum, a bacterium sometimes found on rice grains.