Scientists at the Jet Propulsion Laboratory (JPL) recently identified strains of Enterobacter bugandensis, a newly found enterobacterial species, inhabiting the toilet and exercise areas of the International Space Station. Usually found in hospital settings, the strains of Enterobacter infect patients with impaired immunity. Also, they display a high degree of resistance to antibiotics. However, the initial impression is that the strains found on the ISS are not harmful to humans. Anyway, the fact that such organisms were found on an orbiting space station is alarming, and the implications of the situation are to be fully worked out in order to ensure the safety of the astronauts in the present and future missions.
Scientists at the JPL have been studying the bacterial communities that live on the surfaces inside the space station for the last few years. Some of their findings were published in the journal BMC Microbiology a few days ago, with Dr. Nitin K Sing as the lead author. Dr. Kasthuri Venkateswaran, a member of the research team said that they used various methods to characterize the genomes of the microbes and found that there were five strains of Enterobacter on the ISS. They also observed that the strains were similar to three strains recently identified on earth. Dr. Venkateswaran added that all of them belonged to the same species known as Enterobacter bugandensis, infecting newborn babies and patients whose immune systems are compromised.
The team tried to see whether they showed characteristics of antimicrobial resistance like the ones identified in East Africa, Washington State and Colorado. They also assessed the pathogenic potential (the ability to infect humans) of the strains. Dr. Nitin Singh said that they pose health risks for future missions to the ISS. However, the strains identified were not virulent enough to infect humans in their present state. Yet they are to be monitored constantly since there is a 79 percent theoretical probability that they may cause disease. This means that further investigations will follow.