Contributing Factors for Complications and Outcomes in Patients With Snakebite: Experience in a Medical Center in Southern Taiwan

Use of Antibiotics following Snakebite in the Era of Antimicrobial Stewardship

Even though there are guidelines for the management of snakebite envenoming (SBE), the use of antibiotics in this pathology remains controversial. The aim of this study is to provide a narrative review of the literature and recommendations based on the best available evidence regarding antibiotic use in SBE. We performed a narrative review of relevant literature regarding SBE and antibiotic use as prophylaxis or treatment. A total of 26 articles were included. There is wide use of antibiotics in SBE; nevertheless, infection was not necessarily documented. The antibiotics used varied according to the study, from beta lactams to lincosamide and nitroimidazoles, and from monotherapy to combined antimicrobials. The most common recommendations were to manage skin and soft tissue infections and avoid infectious complications, but these suggestions are not necessarily based on bacteriological findings. Prophylactic use of antibiotics in SBE is discouraged in most studies. Antibiotic prescription in SBE should be based on the susceptibility of microorganisms isolated from the affected tissue or identified in snakes' oral cavities. Antibiotics should be reserved only for patients with a demonstrated infection, or those at a high risk of developing an infection, i.e., presenting severe local envenoming, local signs of infection, or those with incorrect manipulation of wounds. Prospective studies are needed to correlate microbiological findings at the wound site and the response to antibiotic use.

Taiwan cobra envenoming: serum venom concentration before and after specific treatment and relationship with debridement of necrotic wound tissue

Background

Bivalent freeze-dried neurotoxic (FN) antivenom has been the primary treatment since the 1980s for Taiwan cobra (Naja atra) envenomation in Taiwan. However, envenomation-related wound necrosis is a significant problem after cobra snakebites. In the present study, we analyzed the changes in serum venom concentration before and after antivenom administration to discover their clinical implications and the surgical treatment options for wound necrosis.

Methods

The patients were divided into limb swelling and wound necrosis groups. The clinical outcome was that swelling started to subside 12 hours after antivenom treatment in the first group. Serum venom concentrations before and after using antivenoms were measured to assess the antivenom's ability to neutralize the circulating cobra venom. The venom levels in wound wet dressing gauzes, blister fluids, and debrided tissues were also investigated to determine their clinical significance. We also observed the evolutional changes of wound necrosis and chose a better wound debridement timing.

Results

We prospectively enrolled 15 Taiwan cobra snakebite patients. Males accounted for most of this study population (n = 11, 73%). The wound necrosis group received more antivenom doses than the limb swelling group (4; IQR:2-6 vs 1; IQR:1-2, p = 0.05), and less records of serum venom concentrations changed before/after antivenom use (p = 0.0079). The necrotic wound site may release venom into circulation and cause more severe envenomation symptoms. Antivenom can efficiently diminish limb swelling in cobra bite patients. However, antivenom cannot reduce wound necrosis. Patients with early debridement of wound necrosis had a better limb outcome, while late or without debridement may have long-term hospital stay and distal limb morbidity.

Conclusions

Antivenom can efficiently eliminate the circulating cobra venom in limb swelling patients without wound necrosis. Early debridement of the bite site wound and wet dressing management are suggestions for preventing extended tissue necrosis and hospital stay.

Clinical characteristics and use of antibiotics in a group of patients with snake bites in Colombia

Introduction

Millions of snake bites occur worldwide each year. Clinical practice guidelines generally do not recommend the use of prophylactic antibiotics.

Objective

To determine the sociodemographic, clinical, and pharmacological variables and the use of antibiotics in a group of patients with snake bites in Colombia.

Methods

A retrospective cross-sectional study was carried out. Patients affiliated with a Colombian health insurer who presented with snake bites between 2015 and 2022 were included. The cases were identified from the National Public Health Surveillance System. Sociodemographic, clinical and pharmacological variables were identified. Descriptive and bivariate analyses were performed.

Results

A total of 643 patients were analyzed, with a median age of 30.8 years, and 74.7% were men. The most frequently identified genus of snake was Bothrops (88.8%), and most incidents were classified as mild ophidian accidents (61.6%). A total of 59.7% of patients received snake antivenom. A total of 13.8% and 2.2% of the patients had cellulitis or abscesses, respectively. A total of 63.5% received antibiotics (50.6% for prophylaxis and 12.9% for treatment), especially cephalexin (25.9%), and most of the antibiotic management was considered inappropriate (91.7%).

Conclusion

Most patients with snake bites received antibiotics, especially for prophylactic purposes, a clinical behavior that goes against current evidence. The use of antibiotics with an unsuitable spectrum for the microorganisms that are usually found in the wounds of these patients is frequent. The development of local clinical practice guidelines is required to help reduce the overprescription of antibiotics, as the excessive use of antimicrobials is the main determinant of antimicrobial resistance.

Clinical study of anti-snake venom blockade in the treatment of local tissue necrosis caused by Chinese cobra (Naja atra) bites

OBJECTIVE

This study aimed to evaluate the clinical therapeutic efficacy of anti-snake venom serum blockade in treating local tissue necrosis caused by Chinese cobra (Naja atra) bites.

METHODS

Patients bitten by a Chinese cobra (Naja atra) (n = 50) that met the inclusion criteria were randomly divided into two groups: the experimental group (n = 25) and the control group (n = 25). The experimental group received regular as well as anti-snake venom serum blocking treatment, whereas regular treatment plus chymotrypsin blocking therapy was given to the control group. The necrotic volumes around snake wounds in these groups were detected on the first, third and seventh days. On the third day of treatment, some local tissues in the wounds were randomly selected for pathological biopsy, and the necrosis volume of the local tissue was observed. Furthermore, the amount of time required for wound healing was recorded.

RESULTS

On the third and seventh days post-treatment, the necrotic volume of the wound of the experimental group was much smaller than that of the control group, and the experimental group's wound healing time was shorter than that of the control group (all p < 0.05). Moreover, the pathological biopsies taken from the control group showed nuclear pyknosis, fragmentation, sparse nuclear density, and blurred edges, and the degree of necrosis was much higher than that of the experimental group.

CONCLUSIONS

Anti-snake venom blocking therapy is a new and improved therapy with good clinical effect on local tissue necrosis caused by Chinese cobra bites; moreover, it is superior to conventional chymotrypsin blocking therapy in the treatment of cobra bites. It can better neutralize and prevent the spread of the toxin, reduce tissue necrosis, and shorten the course of the disease by promoting healing of the wound. Furthermore, this treatment plan is also applicable to wound necrosis caused by other snake toxins, such as tissue necrosis caused by elapidae and viper families.

CLINICAL TRIAL REGISTRATION

This trial is registered in the Chinese Clinical Trial Registry, a primary registry of International Clinical Trial Registry Platform, World Health Organization (Registration No. ChiCTR2200059070; trial URL:http://www.chictr.org.cn/edit.aspx?pid=134353&htm=4).

Risk of stroke with antivenom usage after venomous snakebite in Taiwan: a population-based cohort study

BACKGROUND AND PURPOSE

Stroke is a rare complication of snakebites, but may lead to serious sequelae. We aimed to explore the relationship between venomous snakebite and the risk for acute stroke, in a nationwide population-based cohort study.

METHODS

This retrospective cohort study used claims data between 1 January 2000 and 31 December 2012, from the Taiwan National Health Insurance Research Database. The study included data of patients aged 18 years or older with venomous snakebite (n = 535), matched for propensity score with controls without venomous snakebite (n = 2140). The follow-up period was the duration from the initial diagnosis of venomous snakebite and administration of antivenom to the date of an acute stroke, or until 31 December 2013. The competing risk model was used to estimate the hazard ratio (HR) and 95% confidence intervals (CIs) of stroke, ischemic stroke and hemorrhagic stroke, after adjusting for demographic and other possible stroke risk factors.

RESULTS

The adjusted HR for the venomous snakebite group compared with the control group was 2.68 for hemorrhagic stroke (95% CI = 1.35-5.33). Stratified analysis showed that the older age group (>65 years old) had a higher risk of hemorrhagic stroke. A 2.72-fold significant increase in the risk for hemorrhagic stroke was observed following venomous snakebite with antivenom usage (95% CI = 1.41-5.26).

CONCLUSION

Venomous snakebite is associated with an increased risk of hemorrhagic stroke after the use of antivenom. Further study of the underlying mechanism is warranted.

Cytotoxicity of Venoms and Cytotoxins from Asiatic Cobras (Naja kaouthia, Naja sumatrana, Naja atra) and Neutralization by Antivenoms from Thailand, Vietnam, and Taiwan

Envenoming by cobras (Naja spp.) often results in extensive local tissue necrosis when optimal treatment with antivenom is not available. This study investigated the cytotoxicity of venoms and purified cytotoxins from the Monocled Cobra (Naja kaouthia), Taiwan Cobra (Naja atra), and Equatorial Spitting Cobra (Naja sumatrana) in a mouse fibroblast cell line, followed by neutralization of the cytotoxicity by three regional antivenoms: the Thai Naja kaouthia monovalent antivenom (NkMAV), Vietnamese snake antivenom (SAV) and Taiwanese Neuro bivalent antivenom (NBAV). The cytotoxins of N. atra (NA-CTX) and N. sumatrana (NS-CTX) were identified as P-type cytotoxins, whereas that of N. kaouthia (NK-CTX) is S-type. All venoms and purified cytotoxins demonstrated varying concentration-dependent cytotoxicity in the following trend: highest for N. atra, followed by N. sumatrana and N. kaouthia. The antivenoms moderately neutralized the cytotoxicity of N. kaouthia venom but were weak against N. atra and N. sumatrana venom cytotoxicity. The neutralization potencies of the antivenoms against the cytotoxins were varied and generally low across NA-CTX, NS-CTX, and NK-CTX, possibly attributed to limited antigenicity of CTXs and/or different formulation of antivenom products. The study underscores the need for antivenom improvement and/or new therapies in treating local tissue toxicity caused by cobra envenomings.

The development of surgical risk score and evaluation of necrotizing soft tissue infection in 161 Naja atra envenomed patients

BACKGROUND

Naja atra bites cause wound necrosis, secondary infection, and necrotizing soft tissue infection (NSTI) requiring repetitive surgeries. Little information is known about the predictors for surgery after these bites.

MATERIALS AND METHODS

We retrospectively evaluated 161 patients envenomed by N. atra, 80 of whom underwent surgery because of wound necrosis and infection. We compared the patients' variables between surgical and non-surgical groups. To construct a surgical risk score, we converted the regression coefficients of the significant factors in the multivariate logistic regression into integers. We also examined the deep tissue cultures and pathological findings of the debrided tissue.

RESULTS

A lower limb as the bite site, a ≥3 swelling grade, bullae or blister formation, gastrointestinal (GI) effects, and fever were significantly associated with surgery in the multivariate logistic regression analysis. The surgical risk scores for these variables were 1, 1, 2, 1, and 2, respectively. At a ≥3-point cutoff value, the model has 71.8% sensitivity and 88.5% specificity for predicting surgery, with an area under the receiver operating characteristic curve of 0.88. The histopathological examinations of the debrided tissues supported the diagnosis of snakebite-induced NSTI. Twelve bacterial species were isolated during the initial surgery and eleven during subsequent surgeries.

DISCUSSION AND CONCLUSIONS

From the clinical perspective, swelling, bullae or blister formation, GI effects, and fever appeared quickly after the bite and before surgery. The predictive value of these factors for surgery was acceptable, with a ≥3-point risk score. The common laboratory parameters did not always predict the outcomes of N. atra bites without proper wound examination. Our study supported the diagnosis of NSTI and demonstrated the changes in bacteriology during the surgeries, which can have therapeutic implications for N. atra bites.

Characteristics of Snakebite-Related Infection in French Guiana

Wound infection is frequently reported following snakebite (SB). This study is retrospective. It was conducted in the emergency department and the Intensive Care Unit (ICU) of Cayenne General Hospital between 1 January 2016 and 31 July 2021. We included 172 consecutive patients hospitalized for SB envenoming. All patients were monitored for wound infection. Sixty-three patients received antibiotics at admission (36.6%). The main antibiotic used was amoxicillin–clavulanate (92.1%). Wound infection was recorded in 55 cases (32%). It was 19% in grade 1, 35% in grade 2, and 53% in grade 3. It included abscess (69.1%), necrotizing fasciitis (16.4%), and cellulitis (21.8%). The time from SB to wound infection was 6 days (IQR: 3–8). The main isolated microorganisms were A. hydrophila and M. morganii (37.5% and 18.8% of isolated organisms). Surgery was required in 48 patients (28.1%), and a necrosectomy was performed on 16 of them (33.3%). The independent factors associated with snakebite-associated infection were necrosis (p < 0.001, OR 13.15, 95% CI: 4.04–42.84), thrombocytopenia (p = 0.002, OR: 3.37, 95% CI: 1.59–7.16), and rhabdomyolysis (p = 0.046, OR: 2.29, 95% CI: 1.02–5.19). In conclusion, wound infection following SB is frequent, mainly in grade 2 and 3 envenomed patients, especially those with necrosis, thrombocytopenia, and rhabdomyolysis. The main involved bacteria are A. hydrophila and M. morganii.

Snake Bite Management: A Scoping Review of the Literature

Background:

Around the world, snake bite envenomation remains an underreported human health hazard. Envenomation can cause local and systemic complications, especially when there is a lack of antivenom availability. Although there are established guidelines regarding snake bite management acute care, there is a paucity of data regarding surgical intervention and the plastic surgeon’s role treating this unique patient population.

Methods:

A review was conducted identifying relevant published articles involving snake bite management and treatment in PubMed and EMBASE.

Results:

One hundred ten articles were identified and 77 met inclusion criteria. Snake bite envenomation can result in complications that are dependent upon a variety of variables. The literature has shown the best field treatment to be timely transportation to the nearest medical facility, along with antivenom administration. The cytotoxic, hemotoxic, and neurotoxic effects of venom can cause a variety of local soft tissue and systemic complications. Surgical interventions such as fasciotomies, wound debridements, skin grafts, and tissue flaps may be necessary in these patients to optimize functional and aesthetic outcomes. Disparities in access to care in resource limited settings are discussed.

Conclusions:

Global health disparities and insufficient antivenom distribution create an inequality of care in snake bite patients. Plastic surgeons have an important role in managing acute and chronic complications of snake bite envenomations that can lead to improved patient outcomes.

Wound Infections from Taiwan Cobra (Naja atra) Bites: Determining Bacteriology, Antibiotic Susceptibility, and the Use of Antibiotics-A Cobra BITE Study

Wound necrosis and secondary infection are common complications after Naja atra bites. Clinical tools to evaluate the infection risk after Taiwan cobra bites are lacking. In this Cobra BITE study, we investigated the prevalence of wound infection, bacteriology, and corresponding antibiotic usage in patients presenting with Taiwan cobra snakebites. Patients with wound infection lacking tissue necrosis were included in developing Cobra BITE score utilizing univariate and multiple logistic regression, as patients with wound necrosis require antibiotics for infection treatment. 8,295,497 emergency department visits occurred in the span of this study, with 195 of those patients being diagnosed as having cobra bites. Of these patients, 23 had wound necrosis, and 30 had wound infection, resulting in a wound infection rate of 27.2% (53/195). Enterococcus faecalis and Morganella morganii were the main bacteria identified in the culture report regardless of whether patients’ wounds had necrosis. As per our Cobra BITE score, the three factors predicting secondary wound infection after cobra bites are hospital admission, a white blood cell count (in 103/µL) × by neu-trophil-lymphocyte ratio value of ≥114.23, and the use of antivenin medication. The area under the receiver operating characteristic curve for the Cobra BITE score system was 0.88; ideal sensitivity and specificity were 0.89 and 0.76. This scoring system enables the assessment of wound infections after N. atra bites, and it could be modified and improved in the future for other Naja spp. bites.

The role of a point-of-care ultrasound protocol in facilitating clinical decisions for snakebite envenomation in Taiwan: a pilot study

BACKGROUND

The incidence of acute compartment syndrome (ACS) following snakebite envenomation may be seriously overestimated in Taiwan. Snakebite-induced ACS is difficult to determine solely by clinical examination. Snakebite patients previously underwent surgical intervention based on speculation and general clinical examinations suggesting ACS presentations instead of direct intracompartmental pressure (IP) measurement prior to fasciotomy. Point-of-care ultrasound (POCUS) is a relatively widely available noninvasive tool. This study aimed to evaluate snakebite-envenomated patients for the presence of subcutaneous edema and diastolic retrograde arterial flow (DRAF).

MATERIALS AND METHODS

Snakebite patients were prospectively recruited between 2017 and 2019. All patients were examined with POCUS to locate edema and directly visualize and measure the arterial flow in the compressed artery. The presence of DRAF in the compressed artery is suggestive of ACS development because when compartment space restriction occurs, increased retrograde arterial flow is observed in the artery.

RESULTS

Twenty-seven snakebite patients were analyzed. Seventeen patients (63%) were bitten by Crotalinae snakes, seven (26%) by Colubridae, one (4%) by Elapidae, and two (7%) had unidentified snakebites. All Crotalinae bit patients received antivenom, had subcutaneous edema and lacked DRAF in a POCUS examination series.

DISCUSSION

POCUS facilitates clinical decisions for snakebite envenomation. We also highlighted that the anatomic site of the snakebite is an important factor affecting the prognosis of the wounds. There were limitations of this study, including a small number of patients and no comparison with the generally accepted invasive evaluation for ACS.

CONCLUSIONS

We are unable to state that POCUS is a valid surrogate measurement of ACS from this study but see this as a starting point to develop further research in this area. Further study will be needed to better define the utility of POCUS in patients envenomated by snakes throughout the world.

Envenomation by Trimeresurus stejnegeri stejnegeri: clinical manifestations, treatment and associated factors for wound necrosis

Background

Trimeresurus stejnegeri stejnegeri bite induces tissue swelling, pain, thrombocytopenia, rhabdomyolysis, and acute renal failure. However, the incidence of coagulopathy, factors associated with wound necrosis, and the appropriate management of this condition have not been well characterized yet.

Materials

This study included patients bitten by T. s. stejnegeri that were admitted to the study hospitals from 2001 to 2016. Patient characteristics, laboratory data, and management approaches were compared in victims with and without wound necrosis.

Results

A total of 185 patients were evaluated: three patients (1.6%) were asymptomatic; whereas tissue swelling and pain, local ecchymosis, wound necrosis, coagulopathy, thrombocytopenia, rhabdomyolysis, and renal impairment were present in 182, 53, 13, 15, 10, 1, and 3 patients, respectively. One patient died from coagulopathy and hemorrhagic shock. Antivenom was administered to all envenomed patients at a median time of 1.8 h after the bite. The median total dose of antivenom was five vials. Chi-square analysis showed that bitten fingers, using cold packs during first aid, presence of bullae or blisters, lymphangitis or lymphadenitis, local numbness and suspected infection to be significantly associated with wound necrosis. After adjustment using a multivariate logistic regression model, only cold packs as first aid, bulla or blister formation, and wound infection remained significant.

Conclusions

The main effects of T. s. stejnegeri envenomation are tissue swelling, pain, and local ecchymosis. We do not recommend the use of cold packs during first aid to reduce wound pain, as this may be a risk factor for wound necrosis. In addition, patients with bulla or blister formation should be carefully examined for subsequent wound necrosis. Antiplatelet use may worsen systemic bleeding. No severe rhabdomyolysis or renal failure was observed in this large case series, we therefore considered that they were not prominent effects of T. s. stejnegeri bite.

Wound Infections of Snakebites from the Venomous Protobothrops mucrosquamatus and Viridovipera stejnegeri in Taiwan: Bacteriology, Antibiotic Susceptibility, and Predicting the Need for Antibiotics-A BITE Study

Snakebites from Taiwan habus (Protobothrops mucrosquamatus) and green bamboo vipers (Viridovipera stejnegeri) account for two-thirds of all venomous snakebites in Taiwan. While there has been ongoing optimization of antivenin therapy, the proper management of superimposed bacterial wound infections is not well studied. In this Bacteriology of Infections in Taiwanese snake Envenomation (BITE) study, we investigated the prevalence of wound infection, bacteriology, and corresponding antibiotic usage in patients presenting with snakebites from these two snakes. We further developed a BITE score to evaluate the probability of wound infections and guide antibiotic usage in this patient population. All snakebite victims who presented to the emergency departments of seven training and research hospitals and received at least one vial of freeze-dried hemorrhagic antivenin between January 2001 and January 2017 were identified. Patient biodata, laboratory investigation results, and treatment modalities were retrieved. We developed our BITE score via univariate and multiple logistic regression analyses. The receiver operating characteristic (ROC) curve was plotted to evaluate the predictive performance of the BITE score. Out of 8,295,497 emergency department visits, 726 patients presented with snakebites from a Taiwan habu or a green bamboo viper. The wound infection rate was 22.45%, with seven positive wound cultures, including six polymicrobial infections. Morganella morganii, Enterococcus spp., Bacteroides fragilis, and Aeromonas hydrophila were most frequently cultured. There were no positive blood cultures. A total of 33.0% (n = 106) of snakebite patients who received prophylactic antibiotics nevertheless developed wound infections, while 44.8% (n = 73) of wound infection patients were satisfactorily treated with one of the following antibiotics: amoxicillin/clavulanic acid, oxacillin, cefazolin, and ampicillin/sulbactam. With the addition of gentamicin, the success of antibiotic therapy increased by up to 66.54%. The prognostic factors for the secondary bacterial infection of snakebites were white blood cell counts, the neutrophil lymphocyte ratio, and the need for hospital admission. The area under the ROC curve for the BITE score was 0.839. At the optimal cut-off point of 5, the BITE score had a 79.58% accuracy, 82.31% sensitivity, and 79.71% specificity when predicting infection in snakebite patients. Our BITE score may help with antibiotic stewardship by guiding appropriate antibiotic use in patients presenting with snakebites. It may also be employed in further studies into antibiotic prophylaxis in snakebite patients for the prevention of superimposed bacterial wound infections.

Clinical manifestations and treatments of Protobothrops mucrosquamatus bite and associated factors for wound necrosis and subsequent debridement and finger or toe amputation surgery

INTRODUCTION

Protobothrops mucrosquamatus bite induces wound necrosis, coagulopathy, thrombocytopenia, rhabdomyolysis, and acute renal failure. The severity of the hematological derangements and associated factors for wound necrosis and subsequent surgery and the appropriate management of these conditions have not been well characterized. Although severe renal failure requiring hemodialysis has been reported following P. mucrosquamatus bite, the culprit snake may be erroneously classified.

MATERIALS AND METHODS

A total of 186 patients with P. mucrosquamatus bites were retrospectively evaluated. They were categorized into group 1 (patients receiving debridement or finger/toe amputation) and group 2 (all other patients) to identify the associated factors for surgery. Characteristic data were compared between groups 1 and 2 and between definite and suspected cases.

RESULTS

No differences were observed between definite and suspected cases in terms of symptomatology and management. Of the 186 patients, 7 (3.8%) were asymptomatic, 179 (96.2%) experienced tissue swelling and pain, and 107 (57.5%) had local ecchymosis. Coagulopathy, thrombocytopenia, and renal impairment were found in 13 (7%), 19 (10.2%), and 7 (3.8%) patients, respectively. None of the patients required transfusion therapy or hemodialysis. Furthermore, no systemic bleeding or death occurred. Antivenom was administered to all 179 envenomed patients at a median of 1.5 h post-bite. The median total dose of the specific antivenom was 5.5 vials. In multivariate logistic regression analysis, finger as the bite site, bullae and blister formation, and wound infection were significantly associated with wound necrosis; whereas finger as the bite site and bullae and blister formation were related to debridement or finger/toe amputation.

DISCUSSION AND CONCLUSIONS

Protobothrops mucrosquamatus envenomation mainly exerts effects on local tissue. Systemic effects are uncommon and generally nonsevere and transient after the treatment with the specific antivenom. We speculated that severe renal failure requiring hemodialysis is not a typical finding of P. mucrosquamatus envenomation. Patients with finger as the bite site and bullae or blister formation should be carefully examined for wound necrosis, secondary infection, and subsequent surgery. Further evaluations of the efficacy of antivenom against local tissue effects and the effect of selective antibiotics in the management of bite wound infection are urgently required. Although the antivenom manufacturer suggested a skin test prior to use, we believed that it could be omitted because it does not accurately predict the allergic responses.

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

Infections secondary to snakebite occur in a number of patients and are potentially life-threatening. Bothrops lanceolatus bites in Martinique average 30 cases per year and may result in severe thrombotic and infectious complications. We aimed to investigate the infectious complications related to B. lanceolatus bite. A retrospective single-center observational study over 7 years (2011–2018) was carried out, including all patients admitted to the hospital because of B. lanceolatus bite. One hundred seventy snake-bitten patients (121 males and 49 females) were included. Thirty-nine patients (23%) presented grade 3 or 4 envenoming. Twenty patients (12%) developed wound infections. The isolated bacteria were Aeromonas hydrophila (3 cases), Morganella morganii (two cases), group A Streptococcus, and group B Streptococcus (one case each). Patients were treated empirically with third-generation cephalosporin (or amoxicillin–clavulanate), aminoglycoside, and metronidazole combinations. Outcome was favorable in all patients. The main factor significantly associated with the occurrence of infection following snakebite was the severity of envenoming (P < 0.05). Our findings clearly point toward the frequent onset of infectious complications in B. lanceolatus–bitten patients presenting with grade 3 and 4 envenoming. Thus, based on the bacteria identified in the wounds, we suggest that empiric antibiotic therapy including third-generation cephalosporin should be administered to those patients on hospital admission.

Antibiotic therapy for snakebite envenoming

There are numerous conflicting recommendations available on the use of antibiotics following snakebite. The present letter to the editor presents some recommendations based on recent studies, and aims to stimulate debate on this topic.

Naja atra snakebite in Taiwan

BACKGROUND

Naja atra snakebite is uncommon in Taiwan and causes distinct effects on its victims. Although the Taiwan government produces its own specific antivenom, little information on the management of N. atra snakebite is available.

MATERIALS AND METHODS

We retrospectively evaluated 183 patients admitted to two medical centers. Of these, 45 were identified as definite cases of N. atra snakebite, 86 as suspected cases, and 52 as clinical cases. Demographic data, symptomatology, and management were compared between these case groups.

RESULTS

Symptomatology and management were similar in the three groups. Among the 183 patients, 10 (5.5%) were asymptomatic and nine (4.9%) had transient and partial ptosis or body weakness. The principal effects were local tissue swelling and pain in 173 patients (94.5%), followed by clinically suspected wound infection in 148 (80.9%), skin necrosis in 120 (65.6%), necrotizing soft tissue infection in 77 (42.1%), fever in 59 (32.2%), and gastrointestinal effects in 53 (29%). The median total dose of specific antivenom needed to treat N. atra envenoming was 10 vials. In the envenomed patients, debridement was required in 74 patients (42.8%), fasciotomy/fasciectomy in 46 (26.6%), and finger or toe amputation in seven (4%). The first operation was performed at a median of 3.5 days after the bite.

DISCUSSION AND CONCLUSIONS

Based on these typical manifestations, clinical diagnosis of N. atra snakebites may be feasible and practical. In contrast to other snakes of Elapidae family, N. atra bite did not cause serious neurological effects. Early surgical consultation should be obtained because half of the patients underwent surgery due to infectious complications. Acute compartment syndrome was the surgical indication in rare cases; however, overestimation of the incidence may have occurred. This syndrome should be confirmed by serial intracompartmental pressure monitoring instead of only physical examination, and a sufficient dose of antivenom should be given prior to surgical decompression.