Bacteriology of Naja atra Snakebite Wound and Its Implications for Antibiotic Therapy

Abstract

Abstract. A total of 112 cases of Naja atra envenomation were examined at two referring hospitals: Taichung Veterans General Hospital in central Taiwan and Taipei Veterans General Hospital (VGH-TP) in northern Taiwan. Overall, 77% (86/112) of cases developed clinically suspected wound infections and 54% (61/112) required surgery secondary to tissue necrosis, finger or toe gangrene, and/or necrotizing fasciitis. Morganella morganii was the most abundant gramnegative bacterial strain isolated from bite wounds, followed by Proteus spp., Aeromonas hydrophila, Pseudomonas aeruginosa, and Providencia spp. in descending order; Enterococcus spp. were the most common gram-positive bacteria and Bacteroides spp. were the only anaerobic bacteria. A few episodes of bacteremia were caused by Bacteroides and Shewanella spp. There were no significant variations in the distribution of bacterial species between these two hospitals except for a higher incidence of M. morganii, Enterococcus spp., and polymicrobial infection observed at VGH-TP, which may have been related to variations in the fecal flora of prey and oral flora of individual snakes in different geographic areas in Taiwan. According to the susceptibility test involving various pathogens, first-line drug options for the management of N. atra snakebite wound infections may include monotherapy with ureidopenicillin or combination therapy with aminopenicillin and a third-generation cephalosporin or fluoroquinolone. A prospective evaluation of empiric antibiotic therapy for the management of N. atra snakebite should be considered.

Wound infection secondary to snakebite

“…In areas of high snakebite prevalence outside SA, a similar spectrum of bacterial species has been found and antibiotic sensitivities reported. [6][7][8][9] The bacterial cause of infected snakebite wounds in northern KZN has been determined by previous work, but antibiotic susceptibility remains untested. A current description of associated morbidity is also required.…”

Infectious Complications Following Snakebite by Bothrops lanceolatus in Martinique: A Case Series

“…Wound infection following snakebite usually accounts for 9-77% of the bitten patients, as described in several studies (Table 4). 5,6,8,[12][13][14][15] The large differences in the reported prevalence of secondary infections in snakebites between different studies can be related to variations in the criteria used to establish the presence of infection. A strict criterion is the laboratory isolation and identification of bacteria from the affected tissues or blood in envenomed patients.…”

“…Local signs suggestive of wound infection included pain, erythema, local warmth, swelling, lymphangitis, purulence, delayed healing, crepitus in soft tissues, discolored or friable granulation tissue, and wound breakdown or dehiscence, as previously listed. 8,9 Because our study was retrospective, if no abnormality was mentioned in the patient record, it was assumed that no infectious complication had resulted from the snakebite.…”

Antibiotic therapy for snakebite envenoming

“…Wound infection following snakebite usually accounts for 9 to 77% of the bitten patients, as described in several studies [2,[4][5][6][7][8]. The large differences in the reported prevalence of secondary infections in snakebites can be related to variations in the criteria used to establish the presence of infection.…”

“…In addition, a high proportion of microbiological cultures are negative because of systematic preemptive use of antibiotics in snake bitten patients. The main involved bacteria are Enterococcus faecalis, Aeromonas hydrophila and Morganella morganii [2,[4][5][6][7][8][9].…”