Isolation, identification, and whole genome sequencing of Enterococcus casseliflavus from forest musk deer

Abstract:

[Background] Enterococcus casseliflavus is an opportunistic pathogenic bacterium with wide distribution in the nature, while there are few studies about this bacterium in forest musk deer. [Objective] We isolated, identified, and sequenced a strain of E.casseliflavus from the liver of a death forest musk deer, aiming to lay a foundation for the prevention and treatment of related diseases in forest musk deer. [Methods] Biochemical tests, drug susceptibility tests, 16S rRNA gene analysis, and bacterial load tests were conducted for the isolate. The results of whole genome sequencing were used to annotate gene functions and analyze genetic evolution. [Results] The isolated strain was identified based on 16S rRNA gene analysis and average nucleotide identity as E.casseliflavus, which was consistent with the results of biochemical tests. The strain was named Dec0527. The strain was resistant to cephalexin, aztreonam, amikacin, and tobramycin, and it was sensitive to doxycycline, tetracycline, chloramphenicol, sulfamethoxazole trimethoprim, some β-lactams, aminoglycosides, and quinolones. The bacterial load test results showed that the invasiveness of strain Dec0527 to the liver was significantly higher than that to the heart, lung, spleen, and kidney. The genome length of this strain was 3 345 060 bp, with the G+C content of 42.55%. Strain Dec0527 carried a variety of virulence genes such as ebpC, tufA, groEL, cpsA, cap8E, and psaA, as well as the genes for resistance to vancomycin and ciprofloxacin. The resistance genes of strain Dec0527 against aminoglycosides, macrolides, and β-lactams were not completely consistent with the drug resistance. In addition, the genome of the strain Dec0527 had 2 circular plasmids and a relatively complete phage region. [Conclusion] We isolated a strain of E. casseliflavus from the liver of a dead forest musk deer and sequenced and analyzed the whole genome of this strain, providing a reference for the prevention and control of diseases in forest musk deer.

Key words:forest musk deer;Enterococcus casseliflavus;drug resistance;whole genome sequencing