Crocodile-killing bacteria identified by Top End researchers

A ground-breaking study by a north Australian research team has identified a deadly bacterium responsible for killing saltwater crocodiles at a Top End Wildlife Park. Led by Menzies School of Health Research (Menzies), the study investigated the deaths of two hatchling saltwater crocodiles at the Wildlife Park using high-resolution whole-genome sequencing and comparative phylogenetics.

The findings identified a common north Australian strain of melioidosis in the hatchlings’ incubator. Melioidosis is a disease of humans and animals endemic to Southeast Asia and northern Australia caused by Burkholderia pseudomallei bacteria.

Infection is normally acquired through cuts, ingestion of contaminated soil or water, or inhalation, particularly during severe weather events. Menzies researcher Audrey Rachlin, the lead author of the study, said that although melioidosis has been identified in a wide array of animal species there has only been one report of a saltwater crocodile being infected by the disease in the Top End and that was more than 30 years ago.

According to Menzies’ Tropical and Emerging Infections Diseases team leader, Professor Bart Currie, collaborative studies with veterinary colleagues have been essential to gaining a better understanding of melioidosis and the danger of the disease to humans.

“Darwin has the highest recorded rates of melioidosis of any city in the world. Fortunately, improvements in prevention, diagnosis and treatment have led to mortality rates reducing to 10 per cent, compared to 30 per cent in earlier years,” Prof Currie said.

The study was recently published in the journal, Microbial Genomics. The study was a collaboration between Menzies, Charles Darwin University’s Research Institute for the Environment and Livelihoods, Berrimah Veterinary Laboratory, and the Royal Darwin Hospital and Northern Territory Medical Program. The paper can be viewed here.