Bite injuries to the hand: microbiology, virology and management

Fifteen-minute consultation: Management of mammalian bites in children - from local wound care to prophylactic antibiotics

Animal and human bites are a common reason for emergency consultation, especially in children. The most common complication of bite wounds is local infection. Systemic infections are much rarer. The key in reducing the risk of infection after a mammalian bite is local wound management with either primary or delayed closure. The benefit of administering prophylactic antibiotics is controversial.In this review, we provide a summary of the current evidence for the management of mammalian bites in children, including recommendations for appropriate investigations, wound management, administration of prophylactic and therapeutic antibiotics and the prevention of systemic infections.

Canine Saliva as a Possible Source of Antimicrobial Resistance Genes

While the One Health issues of intensive animal farming are commonly discussed, keeping companion animals is less associated with the interspecies headway of antimicrobial resistance. With the constant advance in veterinary standards, antibiotics are regularly applied in companion animal medicine. Due to the close coexistence of dogs and humans, dog bites and other casual encounters with dog saliva (e.g., licking the owner) are common. According to our metagenome study, based on 26 new generation sequencing canine saliva datasets from 2020 and 2021 reposited in NCBI SRA by The 10,000 Dog Genome Consortium and the Broad Institute within Darwin’s Ark project, canine saliva is rich in bacteria with predictably transferable antimicrobial resistance genes (ARGs). In the genome of potentially pathogenic Bacteroides, Capnocytophaga, Corynebacterium, Fusobacterium, Pasteurella, Porphyromonas, Staphylococcus and Streptococcus species, which are some of the most relevant bacteria in dog bite infections, ARGs against aminoglycosides, carbapenems, cephalosporins, glycylcyclines, lincosamides, macrolides, oxazolidinone, penams, phenicols, pleuromutilins, streptogramins, sulfonamides and tetracyclines could be identified. Several ARGs, including ones against amoxicillin–clavulanate, the most commonly applied antimicrobial agent for dog bites, were predicted to be potentially transferable based on their association with mobile genetic elements (e.g., plasmids, prophages and integrated mobile genetic elements). According to our findings, canine saliva may be a source of transfer for ARG-rich bacteria that can either colonize the human body or transport ARGs to the host bacteriota, and thus can be considered as a risk in the spread of antimicrobial resistance.

Packing a Punch: Fight Bite Induced Septic Joint

'Fight bites' constitute a considerable number of accidental human bite injuries. Where the mechanism involves a closed fist contacting another person's teeth, the subsequent injury tends to involve the metacarpophalangeal joint region. These injuries are unique for their seemingly benign appearance on initial presentation. Their presence can easily be missed if the treating physician does not seek investigative history and a high index of suspicion. If improperly managed, fight bites may be associated with the introduction of bacteria that may invade deeper tissues, causing potential debilitation from progressive infection. Our case discusses a 33-year-old female who presented three weeks after an altercation where a fight bite occurred but was not treated with antibiotics on discharge. Her clinical presentation matched a flexor sheath infection, which was revealed after investigation to be a consequence of a septic metacarpophalangeal joint that had also progressed to involve the underlying bones. The case outlines the dangers of improper assessment and management of fight bite injuries and reviews best practices surrounding the recognition, assessment, and treatment of these patients in the Emergency Department.

Bite wounds to the hand - a review

Bite wounds occur as a result of bite by an animal or a human. They are relatively frequent due to the growing number of pets living with people, as well as from inadequate human-animal interactions. The knowledge of most surgeons about the management of these injuries is relatively outdated, whereas the current literature points to important changes in this field. The article presents several aspects concerning epidemiology, classification, bacteriology, and characteristics of bite wounds to the hand. Based on the actual literature, detailed rules for the management of these injuries are described. This information may prove useful in the daily practice of surgeons and doctors at emergency departments who are frequently faced with bite wounds.

"As long as the patient tells you it was a dog that bit him, why do you need to know more?" A qualitative study of how healthcare workers apply clinical guidelines to treat dog bite injuries in selected hospitals in Uganda

Dog-mediated rabies is on the increase in Uganda despite the availability of post-exposure prophylaxis (PEP). PEP procedures are expounded in the Uganda Clinical Guidelines (UCG) of 2016. We assessed adherence by health workers to UCG while managing dog bites in two PEP centers and obtained insights into motivations of their practices. Using qualitative methods, we observed the health worker-patient encounters, reviewed medical records, and interviewed 14 health workers that were involved in managing dog bite injuries. We used deductive thematic analysis to identify codes in themes developed from UCG. We found that much of the history of the bites was taken, but it was neither verified nor written down on the patient's file. Classification of wounds was inaccurate and ancillary laboratory assessments like culture and sensitivity tests were not conducted in all cases. Although antibiotics were given for both treatment and prophylactic purposes, the prescription was based on availability and affordability, not UCG recommendations. Rabies immunoglobulin (RIG) was not administered to deserving patients due to unavailability and high costs to the patient. Anti-rabies vaccine (ARV) was prescribed indiscriminately and some health workers attributed this to pressure from patients. Health education regarding prevention of dog bites was not given to patients due to time constraints on the side of the providers as a result of high caseloads at the emergency departments. Challenges to adherence to guidelines were identified as frequent ARV stock outs; inadequate cooperation among health facilities; and insufficient knowledge and skills on how injuries and rabies should be managed. We conclude that clinical management of dog bites is not fully in line with UCG. We argue that adoption of an integrated bite case management and cost-saving strategies as well as continuing medical education programs on rabies control and management could improve the clinical management of dog bites.

[Infections of the Hand after Bite Injuries]

Bite injuries are common. Along with the resulting complications, they represent approximately 1-2 % of all emergency department visits. In over 75 %, the hands are affected. In Northern Europe, bites and subsequent infections are mainly caused by dogs and cats but also by humans.Up to 40 % of all hand infections are caused to bite injuries. Due to the multiple and complex compartments as well as the low soft tissue coverage of functionally relevant structures, even the smallest and most superficial bite injuries of the hand lead to infections. Any bite injury to the hand may subsequently may result in a fulminant infection and, rarely, even death.The spectrum of pathogens from the oral flora of the biting animal or person is diverse and includes aerobic and anaerobic bacterial strains. Bite injuries represent a major challenge for both the injured person and the attending physician. The rate of complications has been shown to increase with delayed medical consultation, lack of medical care and inadequate wound care. In this review, we discuss the types and complications of bite wounds, their potential risk of infection, their pathogen spectrum and appearance, and their effective treatment.

[Osteitis/Osteomyelitis of the Hand and Wrist]

Osteomyelitis of the hand and wrist is uncommon compared to the infections of the long bones but not rare. There is poor evidence on many answers to questions concerning this disease. This includes careful consideration of the prevalence, pathogenesis, microbiology, diagnostic methods and the conservative, medical and surgical treatment. The emergence of the disease can subdivided in post-traumatic, postoperative, spread from contiguous infections and hematogenous. The individual patient-specific risk must be considered. Early diagnosis and correct management are essential to preserve bony structures and the articular function of the hand. A two-step surgical procedure is usually necessary, but uncertainties about the optimal treatment are still existing. Satisfactory control rates of the infection and successful bone reconstructions can be achieved. But complications, a limited range of motion and amputations of finger parts can still not be avoided in all cases.

Seal bites at sub-Antarctic Marion Island: Incidence, outcomes and treatment recommendations

Seal biologists at Marion Island (Southern Ocean) are in frequent contact with seals. During research activities, biologists may be bitten by seals, yet no standardised protocol for treating such bites is in place. Information on 22 seal bite cases at Marion Island was collected. Treatment of these bites varied, reflecting a need for standardised protocols for the treatment of bites. Recommendations for the in-field treatment of bites are presented. Five of the 22 cases had some symptoms which resembled ‘seal finger’ – a zoonotic infection, usually of the hands, that is contracted after a person comes into contact with tissues of seals or is bitten by one. However, in four of these cases, symptoms subsided within 4 days without antibiotic treatment; in the fifth case antibiotics were administered and symptoms subsided in 4 days. There is little evidence of the occurrence of seal finger at Marion Island, but this deserves further investigation.

Acute carpal tunnel syndrome of the hand following a cat bite

Cat bites at the hand are common situation in emergency departments. Neglected or poorly supported, these lesions sometimes lead to serious injuries that may compromise the function of the hand. Pasteurellamultocida is the most offending germ in these lesions, despite their sensitivity to antibiotics; it can sometimes lead to deep infections involving the skin, bones and joints. Acute carpal tunnel syndrome is exceptional after cat bite. We report a case of a 56 Year old female presenting with an acute carpal tunnel syndrome associated with compartment syndrome of the right hand 6 days after a cat bite of her right thumb. The patient was treated by surgery to relieve the median nerve. Microbiology identified PasteurellaMultocida.