Abstract：Objective To reveal the molecular typing and drug resistance of clinical isolates of Corynebacterium striatum in China, and provide evidence for the prevention and treatment of Corynebacterium striatum infections. Methods A multi-center cross-sectional study method was used to collect 197 isolates of Corynebacterium striatum from clinical specimens between October 2017 and January 2018 in a tertiary hospital from Guangdong, Tangshan, and Beijing, respectively. We used the microdilution broth method to measure the minimal inhibitory concentration. Aminoglycoside modifying enzyme (AME) genes [aph(3'')-Ib, aph(6)-Id, aac(6')-Ib, aadA, aph(3')-IIIa and AAC(6')-Ie-APH(2'')-Ia], ribosomal RNA methylases genes (ermX) ribosomal protection proteins genes (tetW), efflux pump proteins genes (tetL), and carbapenemase genes (blaIMP, blaVIM, blaOXA-48, blaNDM, blaKPC) were detected by PCR using primers specific for each gene and by sequencing of the PCR products. The desired target products were sequenced, and then compared with BLAST. Pulsed field gel electrophoresis (PFGE) was performed to typing all isolates. BioNumerics was used to develop the molecular type database based on PFGE patterns. Results The antibiotic susceptibility of 12 different antibiotics was tested based on CLSI M45 document 2016, and 99.5% of all the isolates showed resistant to at least one group of antibiotics. The detection rates of aph(3'')-Ib, aph(6)-I, aac(6')-Ib and aadA genes within gentamycin resistant isolates were 89.3% (67/75), 84% (63/75), 57.3% (43/75) and 4% (3/75), respectively. the detection rates of tetW and tetL genes within tetracycline and doxycycline were 95.5% (105/110) and 97.2% (70/72), and 100% (110/110) and 100% (72/72), respectively. Eighty-two PFGE patterns were identified among the 197 Corynebacterium striatum isolates, among which eleven types were detected in more than five strains. PFGE dominant patterns of Guangdong isolates was CSS01.CN0058; PFGE dominant patterns of Tangshan isolates were CSS01.CN0035, CSS01.CN0051, CSS01.CN0052, and CSS01.CN0048; PFGE dominant patterns of Beijing isolates were CSS01.CN0058, CSS01.CN0070, CSS01.CN0108, and CSS01.CN0015. Conclusions Clinical isolates of Corynebacterium striatum in China are severely resistant against multiple antibiotics, and there exists transmission of multi-drug resistant isolates within a hospital. More extensive systematic monitoring is needed to provide experimental basis for developing control measures.
