Multi-resistant biofilm-forming pathogens on the International Space Station

The International Space Station (ISS) is a confined and closed habitat with unique conditions such as cosmic radiation, andmicrogravity. These conditions have a strong effect on the human and spacecraft microflora. They can affect the immuneresponse of the crew-members, thus posing a threat to their health. Microbial diversity and abundance of microorganismsfrom surfaces, air filters and air samples on the ISS have been studied. Enterobacteriaceae, Bacillus spp., Propionibacterium spp., Corynebacterium spp., and Staphylococcus spp. were among the most frequently isolated bacteria. Microbialgrowth, biofilm formation, stress response, and pathogenicity are affected by microgravity. Increased resistance toantibiotics in bacteria isolated from the ISS has often been reported. Enterococcus faecalis and Staphylococcus spp. isolatesfrom the ISS have been shown to harbor plasmid-encoded transfer genes. These genes facilitate the dissemination ofantibiotic resistances. These features of ISS-pathogens call for novel approaches including highly effective antimicrobialswhich can be easily used on the ISS. A promising material is the antimicrobial surface coating AGXX, a self-recyclingmaterial consisting of two noble metals. It drastically reduced microbial growth of multi-resistant human pathogens, such asstaphylococci and enterococci. Further novel approaches include the application of cold atmospheric plasma for thesterilization of spacecrafts.

Mossambicus tilapia (Oreochromis mossambicus) collected from water bodies impacted by urban waste carries extended-spectrum beta-lactamases and integron-bearing gut bacteria.

Oreochromis mossambicus (Peters 1852) (Tilapia) is one of the most consumed fish globally. Tilapia thrives well in environments polluted by urban waste, which invariably contain antibiotic-resistant bacteria and antibiotic resistance genes (ARGs). Thus, Tilapia surviving in such polluted environments may serve as a potential source for dissemination of ARGs. To investigate this, we isolated bacterial strains from gut of Tilapia found in polluted rivers and lakes near Pune, India, and studied the prevalence of resistance genes bymolecularmethods. A total of 91 bacterial strains were obtained, which include fish pathogens and human pathogens such as Aeromonas hydrophila, Klebsiella pneumoniae, E. coli, Serratia marcescens, Enterobacter spp. and Shigella spp. Overall the prevalence of class 1 integrons, class 2 integrons, extended-spectrum betalactamases (ESBLs) blaCTX-M, blaSHV and aac(6')-Ib-cr gene was 38%, 24%, 38%, 31% and 31% respectively. Forty-two percent of the Enterobacteriaceae strains carried blaCTX-M gene, which is a common ESBL gene in clinics. The study demonstrates that tilapia found in the polluted waters can serve as reservoirs and an alternative route for human exposure to clinically important ARG-carrying bacteria. The consumption and handling of these fish may pose a potential health risk.