NASA organises checks to ensure International Space Station is free from bad bugs, has clean living environment

NASA scientists are keeping a close watch and organising regular checks to make sure that the International Space Station (ISS) is free from bad bugs like bacteria and other micro-organisms, the US space agency has said.

With this, NASA wants to ensure that the ISS has one of the cleanest living environments. "Once every three months, we sample from two locations in each module of the US segment of the station," Mark Ott, a microbiologist at NASA's Johnson Space Center, said in a statement.

The researchers cultured the samples from surfaces and air on plates containing a growth medium, one specific for bacteria and the other for fungi. Those plates return to the ground and scientist identify each organism that grows on them.

11 strains of bacterium belonging to Bacillus anthracis, cereus, thuringiensis group, or Bacillus cereus group were identified.

Some bad bugs are included in this large family of microbes. Bacillus is extremely common on the Earth and around humans. Finding this type of bacteria on ISS is not unusual, the scientists said.

Researchers used DNA hybridisation to identify individual species in the samples. Some closely matched to Bacillus anthracis type strains but they did not have the physical characteristics or the toxin-producing plasmids required to consider them a potential risk.

Drinking water on the space station is treated similar to the water we drink on Earth in order to kill and keep micro-organisms from growing with regular monitoring on the station's drinking water systems.

"The astronauts' drinking water is, microbiologically speaking, cleaner than just about anything they drink on earth," Ott said.

In addition, the medical staff keeps a particularly sharp eye out for micro-organisms that pose a risk to the health of astronauts and when any turn up, the space station gets a more-thorough-than-usual cleaning.

"We should be investigating new and different ways of monitoring spacecraft for micro-organisms but we must be careful when we interpret the results," Ott added.

Continued research is being done to understand what organisms grow on the space station and how they affect an astronaut's health, the scientists said.

The study was published in the journal of Microbiome.

(With inputs from PTI)