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Quality Improvement Study

Appropriate antibiotics in dog bite injuries: an audit study

Al Omran, Yasser BSc (Hons), MBBS, MRCS, MRCP, MSc (Dist)a; Evans, Ellie BA (Hons)b,; Jordan, Chloe BSc (Hons)b; Yang, Ding BSc (Hons), MBBS, MRCS (ENT)c; Huq, Shahidal BSc (Hons), MBBS, PHD, FRCS (Plast)d

Author Information
doi: 10.1097/SR9.0000000000000009
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Dog bites are a common injury and pose a major public health problem to adults and children worldwide1. In the United Kingdom, ~250,000 people who have been bitten by a dog attend minor injuries and emergency units each year2. In all, 2.7% of these are admitted to hospital for surgical debridement or intravenous antibiotics3. The risk of a dog bite is reported to be 18.7 per 1000 population per year, with ~25% of the general population having reported being bitten by a dog during their lifetime4.

In recent years, the incidence of dog-inflicted wounds, which include scratches, punctures, lacerations and evulsions has continued to increase5,6. Appropriate management of these injuries is essential due to the high risk of infection, with the reported rates in the literature between 2% and 20%7. Infected bite wounds manifest as swelling, erythema, and tenderness at the site, with a potential for serious complications8. The microbiology of bite wounds is largely polymicrobial in nature, with the predominant organism cultured from infected wounds depending on the time of presentation. For wounds sampled within 12 hours of injury, the infection is most likely to be due to the Pasteurella species, whereas those sampled more than 24 hours following the incident are more likely to be infected with staphylococci9.

The National Institute for Health Care and Excellence (NICE) recommends co-amoxiclav as the first-choice agent both for prophylaxis and treatment for patients who are not penicillin allergic. For those who are allergic to penicillin, NICE recommends they be prescribed oral doxycycline with metronidazole, or if severe, intravenous metronidazole with either intravenous cefuroxime or ceftriaxone10. Prophylaxis is not routinely offered and only reserved for those at high risk of infection: bites that have broken the skin and caused bleeding.

The United Kingdom adopts a pragmatic approach to managing dog bites, with management based on opinion consensus, as opposed to being evidence based. Al-Himdani et al11 reported that only 14 plastic surgery units across the United Kingdom (28%) had a formal protocol or used NICE guidelines when managing dog bites. All units offered prophylactic antibiotics for patients presenting with a dog bite, with the route of administration and duration of therapy varying across UK units. These multiple variations highlight the lack of consistency in the approach and overall management of dog bites.

At the time of the audit, it was anecdotally observed within The University Hospital North Midlands NHS Foundation Trust that many patients with dog bites were being readmitted with worsening infection after having been prescribed antibiotics against anti-microbial guidelines. One explanation for this may be that antimicrobial guidelines at the time were limited (Fig. 1). This audit aimed to improve the standard of antimicrobial prescribing in dog-bite injuries within the trust, and wanted to ensure that all patients are managed in line with current NICE guidelines10.

Figure 1
Figure 1:
Preaudit antimicrobial guidelines at University Hospital North Midlands NHS Foundation Trust for mammalian bites. Please note, there was no detail on severity of the bite injury, and no guidance on appropriate intravenous antibiotics was provided.

The audit


The authors identified 69 patients who were admitted to the Royal Stoke University Hospital with dog bites between January and December 2018.


Authors found that among the 69 patients admitted with dog bites in 2018 under the care of the Plastic Surgery Department, 14 patients (20%) were initially prescribed flucloxacillin, which is against the microbiology guidelines and proves to be ineffective against the common bacterial organisms seen in such injuries10.

The intervention

Authors noted a lack of detail within the University Hospital of North Midlands NHS Trust animal bite guidelines may be contributing to the frequent prescription of incorrect antibiotics (Fig. 1). The guidelines neither distinguished between nonsevere and severe infections, nor suggested any use of intravenous (IV) antibiotics. Authors therefore liaised with the microbiology team and the antimicrobial governance team at the Royal Stoke University Hospital. Their discussions, along with advice being added to NICE guidelines in November 201910, led to new guidelines placed on the trust antimicrobial guidelines and on the MicroGuide App (Fig. 2). This new guide specified that IV co-amoxiclav, or IV ciprofloxacin, and IV metronidazole for those with a penicillin allergy, should be used for severe dog bites12. MicroGuide also added that delayed bites should be treated as per NICE guidance.

Figure 2
Figure 2:
Changes to the antimicrobial guidelines at University Hospital North Midlands NHS Foundation trust for mammalian bites. Please note, choice of antibiotic is separated into not-severe and severe, and provides an intravenous option.

The reaudit

A prospective reaudit was conducted between November 2019 and February 2020 within University Hospital North Midlands. Twenty-two patients with dog bites were either seen in CTS clinic, or admitted. 100% compliance with guidance was found.


The results of the initial audit were concerning, with 20% of patients admitted under the care of the Plastic Surgery Department to the University Hospital North Midlands being prescribed the incorrect antibiotics. With the incidence of UK dog bites requiring admission continuing to rise, with a 76% increase between 2005 and 2015, and an almost 5% increase in admissions between 2015 and 2018, the need to treat them in a consistent and effective manner is imperative13,14. Indeed, after the intervention, in which the trust’s antimicrobial guidelines and the trust-specific MicroGuide app added guidance for the use of IV antibiotics, and distinguished between treatment for non-severe and severe bites, compliance with guidance rose to 100%.

The most common bacterial genus to be isolated from dog bite wounds is the Pasteurella species9. Pasteurella multocida, which has been found in over 50% of dog bites, has shown resistance to both erythromycin and flucloxacillin, and 100% resistance to clindamycin2,15. The resistance profile of Pasteurella species, paired with the polymicrobial nature of dog bites—with 48% having been found to harbor both aerobic and anaerobic bacteria—demonstrates that adherence to MicroGuide and NICE guidelines, and therefore administering broad-spectrum antibiotics such as Co-Amoxiclav, is essential10,13. Doing so will maximize the effectiveness of treatment, thus limiting patient suffering, disability, and costs to the NHS, while limiting the promotion of further antimicrobial resistance.

With a 2015 report finding that only 28% of UK plastic surgery units had a formal protocol in place or used NICE guidance for the treatment of dog bites, it is likely that the majority these units exist similarly to that of the Royal Stoke University Hospital preintervention, with a lack of clear guidance resulting in incorrect antibiotics being prescribed11. Their trusts would therefore also benefit from implementing MicroGuide into their guidelines, in order to help ensure correct antibiotic treatment. A postal survey of 21 UK emergency departments and minor injury units found that only 62% had a protocol when managing dog bites, furthermore 71% routinely administered prophylaxis2. Therefore, ensuring MicroGuide guidance on the management of dog bites is disseminated in Emergency Departments nationwide would further help ensure consistent, optimum treatment is received. Further audits of other plastic surgery units within the United Kingdom would be beneficial, in order to identify lack of guidance and therefore implement it where necessary.

Assistance with the study




Ethical approval


Sources of funding

No sources of support.

Author contribution

All authors contributed have been credited.

Conflicts of interest disclosure

The authors declare that they have no financial conflict of interest with regard to the content of this report.

Research registration unique identifying number (UIN)





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Dog bites; Antibiotics; MicroGuide

Copyright © 2020 The Authors. Published by Wolters Kluwer Health, Inc. on behalf of IJS Publishing Group Ltd.