The Preliminary Study Of Klebsiella Pneumoniae Affected By Space Environment

Background and Objective:As a highly drug resistant and widely spread pathogen,carbapenemase(KPC)-producing Klebsiella pneumoniae represents an urgent public health crisis.Understanding the adaptive and resistance mechanism will be beneficial for controlling the spread of K.pneumoniae and the development of anti-infective therapies.Space environments are associated with a variety of special stressors,such as low gravity,strong radiation,and weak magnetic fields,which can accelerate the microbial mutation rate and introduce more varied mutations.These alterations will not only jeopardize astronauts but also threaten people on Earth.In this study,a K.pneumoniae strain was cultured in the Shenzhou X spacecraft.After spaceflight,we performed phenotypic analyses and comparative genomic and transcriptomic analyses to explore the impact of the extreme environmental conditions encountered in spaceflight on this pathogen.Methods:?The reference strain K.pneumoniae ATCC BAA-1705(F strain)was used in the study,this pathogen was cultivated in the Shenzhou X spacecraft(T strain)and on the ground(D strain)respectively.?We analyzed the morphology sharp,carbon source utilization patterns and chemical sensitivity,drug resistance of the K.pneumoniae strains.?Genome sequencing and transcriptome sequencing were used to study genomic mutations and differentially expressed genes(DEGs)after space flight.? After screening mutation monoclone from T strain,we performed phenotypic analysis and genome sequencing and comparative genomic analysis to explore the impact of the extreme environmental conditions encountered in spaceflight on this pathogen.Results:? The KPC-2-producing K.pneumoniae could overcome environmental hazards and survial after space flight.?Compared with the F strain,the D and T strains showed no significant changes in morphology,ability of biofilm formation,carbon source utilization patterns.However,in the 8%sodium chloride LB medium,the growth rate and final concentration of the bacterial cells decreased in the following sequence:F strain>D strain>T strain.?Plently of mutations were identified in the D and T strains,which were mainly located in non-coding regions.?The D and T strains contained DEGs compared to the F strain.The DEGs in the D and T strains were involved in amino acid transport and metabolism,inorganic ion transport and metabolism,and carbohydrate transport and metabolism.Compared to the D strain,T strain was characterized by the regulation of genes involved in coenzyme transport and metabolism and carbohydrate transport and metabolism.?After space flight,one clone named T169 was selected from T strain,which was more sensitive to cephalosporin,carbapenems,etc..T169 showed no significant changes in morphological shape,ability to form biofilms,ability to utilize carbon sources,but could grow faster than F strain.?Some genomic variants were identified in T169,including losted plasmids.Compared with F strain,T169 had variations in virulence factors and drug resistance genes.Conclusion:The KPC-2-producing K.pneumoniae has superb adaptation to harsh environments and could survival in hostile space environments.Using phenotypic characteristics and high-throughput sequencing analysis,we found that KPC-2-producing K.pneumoniae significantly changed its phenotype,genome and transcriptome after 15 days of spaceflight.Space environment induced drug resistance mutations and some genomic mutations in some K.pneumoniae clones.Our study provides important information about the mechanisms underlying the environmental adaptation and tenacious vitality of highly drug-resistant pathogens.Additionally,this study provides new insights into the prevention of infection or potential therapeutic strategies for astronauts.