Incidence and Risk Factors for Wound Infections after Trimeresurus stejnegeri Snakebites in Taiwan

Area of Science:

• Tropical Medicine
• Infectious Diseases
• Toxicology

Background:

• Snakebite envenomation is a neglected tropical disease, particularly in subtropical regions like Taiwan.
• Trimeresurus stejnegeri, an arboreal pit viper, is the most frequent cause of venomous snakebites in Taiwan, leading to local swelling and potential wound infections.
• Current treatment involves a binary antivenom, F(ab')2 fragments of equine antibodies, against T. stejnegeri and Protobothrops mucrosquamatus.

Purpose of the Study:

• To analyze the incidence of post-envenomation wound infections following Trimeresurus stejnegeri bites.
• To identify factors associated with wound infection development.
• To evaluate the impact of antivenom timing on infection rates and outcomes.

Main Methods:

• Retrospective analysis of 254 patients treated for T. stejnegeri envenomation at Chang Gung Memorial Hospital over a decade.
• Extraction of clinical, laboratory, treatment, and outcome data from electronic medical records.
• Microbial cultures from patient wounds and snake oral cavities to identify causative agents.

Main Results:

• Wound infection was significantly associated with delayed antivenom initiation (adjusted odds ratio: 3.987).
• Infection rates increased with delayed antivenom administration: 20.5% (within 2 hours) to 48.1% (after 6 hours).
• Commonly cultured bacteria included Morganella morganii, Enterobacter cloacae, and Enterococcus faecalis from wounds and snake oral cavities.

Conclusions:

• Early initiation of antivenom treatment, ideally within 6 hours of T. stejnegeri envenomation, is crucial for reducing wound infection incidence.
• Prompt antivenom administration is a key preventive measure against secondary infections.
• Empiric antibiotic therapy with agents like third-generation cephalosporins, quinolones, or piperacillin/tazobactam is recommended for polymicrobial snakebite wound infections.