Characterisation and relative abundance of bacteria present in the urine of a frog

Reproductive technologies are increasingly being adopted to improve the
Q6 conservation management of threatened species. The storage and
transport of sperm is a vital aspect of the practical
implementation of reproductive technologies, however, bacterial
contamination during the storage and transport of sperm samples
presents a biosecurity risk and can contribute to a reduction in
sperm longevity during storage. The present study: 1)
characterised the urinary microbiome (bacterial species
composition and abundance) using culture-independent 16S rRNA
sequencing; 2) quantified the effect of various doses of gentamicin and
streptomycin-penicillin on bacterial abundance (colony-forming
units; CFUs) and; 3) quantified the effect of
antibiotic supplementation on the sperm viability (proportion
live/dead) of spermic urine during a 12-day cold-storage period,
using the common eastern froglet, Crinia signifera. Overall,
urine samples were found to host a diverse array of
bacteria, dominated by the phyla Proteobacteria, Firmicutes, and
Bacteroidetes. Bacterial abundance was significantly reduced in
all antibiotic treatment groups compared to the control group.
Antibiotic supplementation had no effect on sperm
viability between day 0 and day 6 of storage, however, both
antibiotic treatments significantly improved sperm viability from days 9
to 12 of storage compared to the control group. Overall, the
results of this study provide novel insight into the urinary
microbiome, being the first to use a metagenomics approach
to characterise the bacterial community present in the urine of
an amphibian. Importantly, this study provides evidence that
antibiotic supplementation with either gentamicin or
streptomycin-penicillin, minimises bacterial proliferation and
improves sperm viability during cold storage. These findings will
contribute to the development of biosecurity protocols aimed at
reducing the risk of disease transmission and cross-infection
from unwanted bacteria and infectious agents in amphibian captive
breeding programs.