Antimicrobial Resistance And Transmission Characteristics Of Corynebacterium Striatum

Corynebacterium striatum is an emerging multidrug-resistant(MDR)pathogen,primarily among immunocompromised and chronically ill patients,leading to respiratory infections,bacteremia,and occasionally endocarditis.In order to provide a broader understanding of the genomic diversity of C.striatum that contributes to its long-term persistence and transmission in hospitals,we performed three panels of 435 isolates of Corynebacterium striatum in three provinces,Beijing,Hebei and Guangdong,in north and south of China from January 2016 to March 2018.Of these,the majority of the isolates were recovered from sputum(97.0%)and 97.2%of all isolates were recovered form patients over 50 years old.We performed pulse-field gel electrophoresis(PFGE),antimicrobial susceptibility test to all isolates,and whole-genome sequencing were also conducted on some of the isolates.First,our research demonstrated that among 192 isolates recovered in Beijing hospital,from September 2017 to March 2018,nearly all isolates(95.3%,183/192)were MDR.The highest resistance rate was observed for ciprofloxacin(99.0%),followed by cefotaxime(90.6%)and erythromycin(89.1%).PFGE separated the 192 isolates into 79 pulsotypes.Core genome analysis partitioned the 91 isolates sequenced into four clades.Two predominant subclones,clade 3a and clade 4a,were responsible for the hospital-wide dissemination.Genomic analysis further revealed nine resistance genes mobilized by ISCx1 and IS6100 insertion sequences.Second,the majority(96.0%,119/124)of isolates recovered in Beijing hospital in 2016 also showed MDR.PFGE separated the 124 isolates into 43 pulsotypes,including predominant pulsotypes CSS01.CN0015 and CSS01.CN0058 that appeared within this hospital from September 2017 to March 2018.Finally,73 and 46 isolates from Hebei and Guangdong,respectively,from September 2017 to March 2018,showed similar pulsotypes and drug resistance profiles.Isolates from Hebei and Guangdong showed same clades with isolates from Beijing hospital,respectively.In summary,clinical isolates of Corynebacterium striatum in China showed severe resistance against multiple antimicrobial agents,and there did exist transmission of multi-drug resistant isolates within a hospital.C.striatum isolates may adapt through the acquisition and accumulation of resistance against antimicrobial agents,and thus evolve into persistent clones.Multiple clones of C.striatum isolates had been circulating parallelly in China and predominant clones of C.striatum spreading in different regions of China may also share close relationships,and those clones may persist and spread for many years within same region.Transmission of predominant clones of C.striatum may differed by regions.Therefore,more extensive systematic monitoring is needed to provide experimental basis for developing control measures of C.striatum infections.Based on these,we established molecular typing database of C.striatum,including pulsotypes and resistance profiles of 435 C.striatum isolates,respectively,and whole-genome sequencing data of 158 C.striatum isolates.Among these,epidemiological information including isolation date,units,ages and so on,and all except isolate’ background information were completed.