Sandbox/Alejandro

Overview

A bite is a wound received from the mouth (and in particular, the teeth) of an animal or person. Most animal bites are from dogs or cats, and the pathogens in the wound are composed by the normal oral flora of the biting animal and human skin flora.

Animals may bite in self-defense, in an attempt to predate food, as well as part of normal interactions. Other bite attacks may be apparently unprovoked, especially in the case of bites committed by psychologically or emotionally disturbed humans. Some disorders such as Lesch-Nyhan syndrome may cause people to bite themselves.

Bite wounds can be very complex and it is important to address the following aspects:

• Generalized tissue damage due to tearing and scratching.
• Serious hemorrhage if major blood vessels are pierced.
• Infection by bacteria or other pathogens, including rabies.
• Introduction of venom into the wound by venomous animals such as some snakes.
• Introduction of other irritants into the wound, causing inflammation and itching.

Common Pathogens

Almost every bite would have a polimicrobial contamination, especially with bacteria. Some bites have characteristic pathogens associated to the oral flora of the animal that bit.

Most common pathogens according to the type of bite

Bite
Human	Viridans streptococci, S. epidermidis, Corynebacterium, S. aureus, Eikenella, Bacteroides, Peptostreptococci
Dog	Pasteurella canis, S. aureus , Streptococci , Anaerobes (Bacteroides spp, Fusobacterium, Prevotella heparinolytica, Proprionibacteria, and Peptostreptococci)
Cat	Pasteurella multocida, S. aureus, Streptococci , Anaerobes (Bacteroides spp, Fusobacterium, Prevotella heparinolytica, Proprionibacteria, and Peptostreptococci)
Pig	Pasteurella spp, Gram-negative bacilli, Gram-positive cocci, Anaerobes
Monkey	Herpesvirus simiae (B Virus)
Rat	Spirillum minus, Streptobacillus moniliformis
Seal	Mycoplasma spp
Camel

Treatment

Bite wounds are washed, ideally with povidone-iodine soap and water. The injury is then loosely bandaged, but is not sutured due to risk of infection.

Animal bites inflicted by carnivores (other than rodents) are considered possible cases of rabies. The animal is caught alive or dead with its head preserved, so the head can later be analyzed to detect the disease.

Signs of rabies include:

• Foaming at the mouth
• Self-mutilation
• Growling
• Jerky behavior
• Red eyes.

If the animal lives for ten days and does not develop rabies, then it is probable that no rabies infection has occurred.

If the animal is gone, prophylactic rabies treatment is recommended.

The route of administration depends on the depth and severity of the wound, as well as the time that has passed since the bite.

Antibiotic Therapy

▸ Click on the following categories to expand treatment regimens.

Antibiotic Prophylaxis   ▸  Animal Bite

Antibiotic Prophylaxis Preferred Regimen ▸ Amoxicillin-clavulanate 500-875/125 PO q8-12h Alternative Regimen ▸ Clindamycin 300 mg q8h OR ▸ Metronidazole 500 mg PO q8h PLUS ▸ Doxycycline 100 mg q12h OR ▸ TMP-SMX 160/800 mg PO q12h OR ▸ Penicillin VK 500 mg PO q6h OR ▸ Cefuroxime 500 mg PO q12h OR ▸ Moxifloxacin 400 mg PO q24h

Specific Therapy   ▸  Bat Bite   ▸  Camel Bite   ▸  Cat Bite   ▸  Dog Bite   ▸  Human Bite   ▸  Monkey / Primate Bite   ▸  Pig (Swine) Bite   ▸  Racoon Bite   ▸  Rat Bite   ▸  Seal Bite   ▸  Skunk Bite

Human Bite Preferred Regimen ▸ Ampicillin sulbactam 1.5 g IV q6h OR ▸ Cefoxitin 2 gm IV q8h OR ▸ Ticarcillin clavulanate 3.1 g IV q6h OR ▸ Piperacillin-tazobactam 3.375 g IV q6-8h Alternative Regimen (beta-lactam allergy) ▸ Clindamycin 300 mg PO q8h PLUS ▸ Ciprofloxacin 500-750 mg IV q12h OR ▸ Moxifloxacin 400 mg IV q24h OR ▸ TMP-SMX 160/800 mg q12h Dog Bite Preferred Regimen ▸ Amoxicillin-clavulanate 500-875/125 PO q8-12h Alternative Regimen (beta-lactam allergy) ▸ Clindamycin 300 mg PO q8h PLUS ▸ Ciprofloxacin 500-750 mg IV q12h OR ▸ Moxifloxacin 400 mg IV q24h OR ▸ Gatifloxacin 400 mg q24h Cat Bite Preferred Regimen ▸ Amoxicillin-clavulanate 500-875/125 PO q8-12h Alternative Regimen (beta-lactam allergy) ▸ Cefuroxime 500 mg q12h OR ▸ Doxycycline 100 mg q12h Pig (Swine) Bite Preferred Regimen ▸ Amoxicillin-clavulanate 875/125 mg PO q12h Alternative Regimen ▸ Ampicillin sulbactam 1.5 to 3 g IV q6-8h OR ▸ Imipenem cilastatin 1 g IV q6-8h OR ▸ Ceftriaxone 1 g q12 h OR ▸ Cefotaxime 2 g q6 h OR ▸ Ticarcillin clavulanate 3.1 g IV q6hr Monkey / Primate Bite Profilaxis ▸ Valacyclovir 1 g PO q8h x 14 days OR ▸ Acyclovir 800 mg PO 5 times/day Preferred Regimen (without CNS symptoms) ▸ Acyclovir 12.5–15 mg per kg IV q8h OR ▸ Ganciclovir 5 mg per kg IV q12h Preferred Regimen (with CNS symptoms) ▸ Ganciclovir 5 mg per kg IV q12h Adapted from Prevention of and Therapy for B Virus Exposure • CID 2002:35 Uncomplicated Rat Bite Preferred Regimen ▸ Amoxicillin-clavulanate 875/125 mg orally q12h Alternative Regimen (beta-lactam allergy) ▸ Doxycycline 100 mg orally q12h Rat Bite Fever Preferred Regimen ▸ Penicillin G 400,000 - 600,000 IU/day IV x 10-14 days (dose should be increased to 1.2 M if no clinical response) Alternative Regimen ▸ Streptomycin 15 mg/kg/day IM divided q12-24h x 10-14 days OR ▸ Tetracycline 250 to 500 mg orally q6h Adapted from Clin. Microbiol. Rev. January 2007 vol.20 no.1 13-22 Seal Bite Preferred Regimen ▸ Tetracycline 1.5 g 1 dose, then 0.5 g q6h x 4-6 weeks Alternative Regimen ▸ Doxycycline 100 mg q12h x 4-6 weeks Adapted from Journal of Infection (2002) 45: 71±75 Camel Bite Preferred Regimen ▸ Dicloxacillin 250–500 mg PO q6h PLUS ▸ Ciprofloxacin 750 mg PO q12h Alternative Regimen ▸ Cephalexin 500 mg PO q6h PLUS ▸ Ciprofloxacin 750 mg PO q12h Adapted from Eur J Clin Microbiol Infect Dis. 1999;18(12):918-9. Bat Bite Preferred Regimen ▸ Amoxicillin-clavulanate 875/125 mg orally q12h Alternative Regimen ▸ Doxycycline 100 mg orally q12h Racoon Bite Preferred Regimen ▸ Amoxicillin-clavulanate 875/125 mg orally q12h Alternative Regimen ▸ Doxycycline 100 mg orally q12h Skunk Bite Preferred Regimen ▸ Amoxicillin-clavulanate 875/125 mg orally q12h Alternative Regimen ▸ Doxycycline 100 mg orally q12h