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Koala bites cause wound infections in Australia

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December 12, 2018

Three people in Queensland, Australia, were infected with a Lonepinella koalarum-like bacteria after being bitten by koalas, researchers reported in Emerging Infectious Diseases.

Holly A. Sinclair, MD, an advanced trainee in microbiology and infectious diseases with the Royal College of Pathologists of Australasia and Royal Australasian College of Physicians, and colleagues explained that Lonepinella koalarum is a species of gram-negative bacteria found in koala feces.

“This bacterium is the only species of the genus Lonepinella, a member of the family Pasteurellaceae. L. koalarum-related strains have been identified in koala gingiva,” they wrote.

According to their report, a female wildlife worker aged 69 years developed an infection after seeking care in 2014 for wounds on her left wrist and hand caused by a koala bite. Sinclair and colleagues reviewed records for similar cases and discovered two more: a male wildlife worker aged 62 years who was treated for an infection in 2012 after presenting to his physician with a koala bite injury on his thumb; and a woman aged 66 years who presented to a hospital in 2015 with an infected koala bite on her right hand.

Two koalas in a tree
Three people in Queensland, Australia, were infected with a Lonepinella koalarum-like bacteria after being bitten by a koala.
Source: Adobe Stock

All three patients had purulent skin and soft tissue infections requiring washout and surgical debridement, according to Sinclair and colleagues, who compared the infections to those caused by Pasteurella in dog and cat bite wounds.

The first identified patient was initially treated with oral amoxicillin/clavulanic acid, then received intravenous piperacillin/tazobactam for 6 days followed by oral trimethoprim and sulfamethoxazole after the infection was identified. She recovered. The second identified patient received IV ticarcillin/clavulanic acid for 4 days and then oral amoxicillin/clavulanic acid for 7 days. Clinical improvement was reported. The third patient improved after receiving IV piperacillin/tazobactam.

According to Sinclair and colleagues, samples taken from the first case in 2014 revealed Staphylococcus sciuri and two gram-negative coccobacilli. They identified Fusobacterium nucleatum, S. aureus and an unidentifiable gram-negative bacillus from specimens collected from the second patient and isolated an unidentified gram-negative bacillus from specimens collected before and after surgery on the final patient.

Isolates obtained from patients shared a close genetic relationship with L. loalarum, and Sinclair and colleagues reported being 95% confident that three isolates — one from each patient — are an unidentified non-L. koalarum species in the genus Lonepinella.

Lonepinella infections acquired after koala bites can cause clinically significant human skin and soft tissue disease,” they concluded. “In this report, we identified possibly novel Lonepinella-like organisms with a combination of genetic analyses.” – by Marley Ghizzone

Disclosures: The authors report no relevant financial disclosures.

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