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Three Part Question

In [fit and well adults who have been bitten by a non venomous snake] do [prophylactic antibiotics] reduce [the incidence of infection]?

Clinical Scenario

A 26 year old man attends the emergency department having been bitten on his right hand 30 minutes previously by his pet – a non-venomous snake. Examination reveals localised swelling and oedema of his right hand and forearm, he is systemically well, has no relevant previous medical history and is fully anti – tetanus immunised. You know there is the potential for infection from the snakes fangs and oropharynx, as well as contamination from the victim's skin and clothing. You thoroughly clean the wound with local wound toilet, and are happy that there is no fang left in situ. You wonder if prophylactic antibiotics are indicated to reduce the risk of infection.

Search Strategy

Medline 1966–12/01 using the OVID interface
[(exp snake bites OR snake bite$.mp) AND (exp antibiotics OR anti-biotics.mp OR antibiotic$.mp)] LIMIT to human AND English

Search Outcome

60 papers of which 2 were relevant.

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Weed HG, 1993, USA	72 consecutive children and adults with non envenomated snake wounds calling a poisons centre. None of the patients received antibiotics	Observational	Presence of wound infection	No wound infection identified	14% applied topical antibiotics No definition of wound infection No control group
Blaylock RS, 1999, South Africa	363 patients presenting with snake bites – both venomous (88%) and non venomous ( 12%) Antibiotics given if necrosis present (15.2%)	Observational	Presence of wound infection	No infections in patients not given antibiotics	Not randomised Antibiotics given on clinical grounds (presence of necrosis) Very little raw result data provided

Comment(s)

Whilst many studies have identified the variety of potential pathogens from snakebite, few have looked at the role of prophylactic antibiotics and those available are of poor quality. It is interesting to note the low incidence of infection associated with snake bites irrespective of antibiotic treatment or not. Given the low event rate for infection, trials involving larger numbers would need to be undertaken.

Clinical Bottom Line

Prophylactic antibiotics are not indicated in the routine management of patients with snakebites from non-venomous snakes if no necrosis is present.

References

1. Weed HG. Nonvenomous snakebite in Massachusetts: prophylactic antibiotics are unnecessary. Ann Emerg Med 1993;22:220-4.
2. Blaylock RS. Antibiotic use and infection in snakebite victims. South African Med J 1999;89:874-6.