Associate Professor Jennifer Broom ( left ) Infectious diseases physician , University of Queensland , Brisbane , and the Sunshine Coast Hospital and Health Service , Birtinya , Queensland .

Dr Yash Wagh ( right ) Orthopaedic principal house officer , Sunshine Coast Hospital and Health Service , Birtinya , Queensland .

First published online on 9 February 2024

BACKGROUND

MAMMALIAN bite injuries are a

common presentation to both primary care and ED and result in significant morbidity and mortality globally . The annual incidence of dog bite injuries per population in Australia is about 16 / 100,000 . 1 Dog bites ( see figures 1 , 2 and 3 ) are the most frequent bite injuries assessed in Australian EDs ( 71 %) followed by cat bites ( 17 %, see figures 4 and 5 ), human bites ( 5 %, see figure 6 ) and bites from other mammals ( 7 %). 2 About 50 % of patients who present to ED with a bite injury require hospital admission . Surgery is undertaken in 43 % of patients presenting to hospital and IV antibiotics administered in 46 %. 2 Dog bite injuries have the highest risk of requiring surgical procedures . The aspects to consider when assessing a patient with a bite are listed in box 1 .

This How to Treat covers the assessment and management of mammalian bites in Australia and aims to ensure GPs can assess , manage and appropriately refer , and can implement strategies to prevent complications .

ASSESSMENT

Emergency management / wound assessment

EMERGENCY care of a bite injury

includes , first , assessment and management of any life- or limb-threatening injuries ( including control of haemorrhage ) and assessment for any anatomical structures near the wound , including vascular and neurological compromise , and deep tissue involvement . Second , assess the vascular , neurological and motor function of involved areas , and examine for any retained foreign body ( such as teeth ) or underlying fracture . Injuries that require emergent surgical assessment include any requiring a tourniquet for haemorrhage control ( it is important to minimise tourniquet time and thus tissue damage ), neurovascular injuries and facial or neck injuries . Treat patients presenting with signs of wound infection and sepsis via a sepsis pathway , early surgical debridement , and IV antibiotics directed to the likely pathogens .

History of the bite

When a patient who has been bitten

presents for assessment , it is important to determine the species of the biter ( to guide the types of infective risks ) and the geographic location of the injury ( this is particularly important if the bite occurred overseas ). Australia is not a rabies endemic country but rabies risk assessment must be performed for bite injuries acquired overseas .

The size of the animal and the mechanism of injury can guide assessment — for example a large dog with a clenched jaw will confer a significant underlying fracture risk . Cat bites are more commonly puncture wounds ( these are harder to wash out ) and have a higher incidence of infection because of the penetrating nature and the microbiology of the cat mouth . Clenched fist bites (‘ fight bites ’) result from the impact of a clenched fist on the teeth of another human being . This is a common presentation in younger males and is often a delayed presentation . These injuries have a high rate of tendon , cartilage or bone injury and frequent subsequent septic arthritis and osteomyelitis .

Infections of bite injuries are

commonly polymicrobial because of the numerous bacteria in the mouth cavity , and the organisms involved reflect the oral flora of the biter . Generally , animal oral flora includes anaerobic bacteria , streptococci , staphylococci , neisseria , pasteurella , moraxella and corynebacterium species . These organisms are also present in human oral flora , in addition to haemophilus and eikenella species . Specific organisms to consider for different mammalian bites are detailed in table 1 . Infections caused by dog bites are more likely to be caused by human skin flora ( such as Staphylococcus aureus and Streptococcus pyogenes ) whereas infected cat bites are more likely the result of cat oral flora . 3 , 4 It is also important to consider whether the wound has had any significant water exposure , increasing the likelihood of organisms such as aeromonas species ( in fresh or brackish water ) and vibrio species ( in salt water ), as the antibiotic prophylaxis ( if indicated ) may need to cover these organisms . When assessing a human bite injury , also consider the risk for bloodborne virus