Identification of Acinetobacter schindleri isolated from Chinese Giant Salamanders (Andrias davidianus)

Abstract

Abstract At a particular aquaculture facility in Zhangjiajie, Hunan Province, the Chinese giant salamander (Andrias davidianus) exhibited analogous clinical manifestations, culminating in sequential mortalities. This study used rigorous aseptic sampling methods to extract bacteria from the affected liver of salamanders to determine the causative agent behind the decline of amphibians. A bacterial pathogen was isolated from the diseased A. davidianus, and the strain was named DN-3. This isolate was subjected to bacterial identification, antibiotic susceptibility assays, reinfection experiments, and biochemical profiling. The isolated bacterial strain was definitively identified as Acinetobacter schindleri using 16S rRNA sequence analysis. Antibiotic susceptibility testing revealed that this isolate was susceptible to neomycin, macrolides, doxycycline, piperacillin, nitrofurantoin, and carbenicillin. Subsequent reinfection assays, wherein varying concentrations of the bacterial inoculum were administered to healthy salamanders, corroborated that the pathogen elicited varying degrees of morbidity or mortality within an eight-day observation period. The median lethal dosage (LD50) of A. schindleri DN-3 for A. davidianus was calculated to be 6.25×104 CFU/mL. This supports the significant pathogenicity of the strain. The findings of this study furnish empirical underpinnings for the clinical management and epidemiological control of diseases affecting the Chinese giant salamander.