Poor efficacy of preemptive amoxicillin clavulanate for preventing secondary infection from Bothrops snakebites in the Brazilian Amazon: A randomized controlled clinical trial

A Nationwide Study on the Risks of Complications and Healthcare Costs of Snakebite Envenomation in Taiwan

In Taiwan, six medically important venomous snakes, Trimeresurus stejnegeri stejnegeri, Protobothrops mucrosquamatus, Deinagkistrodon acutus, Daboia siamensis, Naja atra, and Bungarus multicinctus, are found. However, comprehensive research on the complications and associated healthcare costs of snakebite envenomation (SBE) is lacking. We retrospectively analyzed pertinent information from the Taiwan National Health Insurance Research Database dated January 2002 to December 2014. We investigated the risk factors for complications and their impact on healthcare costs. Among the 12,542 patients with SBE, those from N. atra or B. multicinctus were more likely to experience wound infections and neurological complications than were those from T. s. stejnegeri or P. mucrosquamatus. In addition, being female, being elderly, and having a Charlson Comorbidity Index equal to or greater than 3 points were associated with an increased likelihood of wound infections and psychological complications. The annual national economic burden averaged US$1,083,624, with an average healthcare cost of US$1,129 per SBE. Snakebite envenomations from N. atra or B. multicinctus, as well as various complications, resulted in significantly higher costs. It is crucial to comprehend the risk factors for complications and their role in increasing expenses to provide insight for tailored healthcare interventions, mitigate complications, and reduce the economic burdens associated with SBEs.

Snakebite-Associated Infections: A Systematic Review and Meta-Analysis

Snakebites still constitute a significant public health problem in developing countries and are considered a neglected tropical condition by the WHO. Snake accidents are associated with substantial morbidity and mortality and may produce secondary complications, such as severe infections. The objective of this systematic review was to determine the prevalence of snakebite infections and characterize the bacteria isolated from these infections. A systematic literature review in five databases was carried out to assess the prevalence of snakebite infection. A meta-analysis was performed using a random-effects model to calculate the pooled prevalence and 95% CIs. Cochran's Q test and the I2 statistic were used to assess between-study heterogeneity. The pooled prevalence of infection due to snakebite was 27.0% (95% CI: 22.0-32.0%), with high heterogeneity among studies (I2 = 99.7%). The prevalence was higher in Asia (32%) than in the Americas (21%). Snakebite infections required surgical interventions in 68% (95% CI: 37.0-98.0%). The leading group of pathogens identified corresponded to Gram-negative bacteria (63%), particularly Morganella morganii (32%), but also, Gram-positive cocci (40%), especially Enterococcus spp. (23%) and Staphylococcus aureus (15%). However, multiple other pathogens, including anaerobes, were found. A high prevalence of snakebite-associated infection has been described, primarily due to M. morganii, with the corresponding implications for empirical therapy. Rational use of antimicrobials is recommended, and this should guide initial empirical treatment. Moreover, isolation and identification of the possible bacteria present in snakebite wounds is recommended in all cases to confirm or rule out associated infection.

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.

The Chinese guideline for management of snakebites

In 2009, the World Health Organization included snakebite on the list of neglected tropical diseases, acknowledging it as a common occupational hazard for farmers, plantation workers, and others, causing tens of thousands of deaths and chronic physical disabilities every year. This guideline aims to provide practical information to help clinical professionals evaluate and treat snakebite victims. These recommendations are based on clinical experience and clinical research evidence. This guideline focuses on the following topics: snake venom, clinical manifestations, auxiliary examination, diagnosis, treatments, and prevention.

Photobiomodulation Therapy to Treat Snakebites Caused by Bothrops atrox: A Randomized Clinical Trial

Importance

Bothrops venom acts almost immediately at the bite site and causes tissue damage.

Objective

To investigate the feasibility and explore the safety and efficacy of low-level laser therapy (LLLT) in reducing the local manifestations of B atrox envenomations.

Design, Setting, and Participants

This was a double-blind randomized clinical trial conducted at Fundação de Medicina Tropical Doutor Heitor Vieira Dourado, in Manaus, Brazil. A total of 60 adult participants were included from November 2020 to March 2022, with 30 in each group. Baseline characteristics on admission were similarly distributed between groups. Data analysis was performed from August to December 2022.

Intervention

The intervention group received LLLT combined with regular antivenom treatment. The laser used was a gallium arsenide laser with 4 infrared laser emitters and 4 red laser emitters, 4 J/cm2 for 40 seconds at each application point.

Main Outcomes and Measures

Feasibility was assessed by eligibility, recruitment, and retention rates; protocol fidelity; and patients' acceptability. The primary efficacy outcome of this study was myolysis estimated by the value of creatine kinase (U/L) on the third day of follow-up. Secondary efficacy outcomes were (1) pain intensity, (2) circumference measurement ratio, (3) extent of edema, (4) difference between the bite site temperature and that of the contralateral limb, (5) need for the use of analgesics, (6) frequency of secondary infections, and (7) necrosis. These outcomes were measured 48 hours after admission. Disability assessment was carried out from 4 to 6 months after patients' discharge. P values for outcomes were adjusted with Bonferroni correction.

Results

A total of 60 patients (mean [SD] age, 43.2 [15.3] years; 8 female individuals [13%] and 52 male individuals [87%]) were included. The study was feasible, and patient retention and acceptability were high. Creatine kinase was significantly lower in the LLLT group (mean [SD], 163.7 [160.0] U/L) 48 hours after admission in relation to the comparator (412.4 [441.3] U/L) (P = .03). Mean (SD) pain intensity (2.9 [2.7] vs 5.0 [2.4]; P = .004), circumference measurement ratio (6.6% [6.6%] vs 17.1% [11.6%]; P < .001), and edema extent (25.8 [15.0] vs 40.1 [22.7] cm; P = .002) were significantly lower in the LLLT group in relation to the comparator. No difference was observed between the groups regarding the mean difference between the bite site temperature and the contralateral limb. Secondary infections, necrosis, disability outcomes, and the frequency of need for analgesics were similar in both groups. No adverse event was observed.

Conclusions and Relevance

The data from this randomized clinical trial suggest that the use of LLLT was feasible and safe in a hospital setting and effective in reducing muscle damage and the local inflammatory process caused by B atrox envenomations.

Trial Registration

Brazilian Registry of Clinical Trials Identifier: RBR-4qw4vf.

Evidence-Based Medicine: Systemic Perioperative Antibiotic Prophylaxis for Prevention of Surgical-Site Infections in Plastic and Reconstructive Surgery

BACKGROUND

After nearly a decade of new data, the Evidence-Based Consensus Conference Statement from the American Association of Plastic Surgeons was updated for prophylactic systemic antibiotics to prevent surgical-site infections (SSI). Pharmacotherapeutic concepts using antimicrobial stewardship were applied for clinical interpretation and management to optimize patient outcomes and minimize resistance.

METHODS

PRISMA, Cochrane, and GRADE certainty of evidence guidelines were implemented for the structure and synthesis of the review. PubMed, Embase, Cochrane Library, Web of Science, and Scopus databases were systematically and independently searched for randomized controlled trials (RCTs). The authors included patients who had plastic and reconstructive surgery and were treated with prophylactic systemic antibiotics administered perioperatively (preoperatively, intraoperatively, or postoperatively). Comparisons were made between active interventions and nonactive interventions (placebo) at different prespecified durations to determine the development of an SSI. Meta-analyses were performed.

RESULTS

The authors included 138 RCTs that met eligibility criteria. RCTs consisted of 18 breast, 10 cosmetic, 21 hand/peripheral nerve, 61 pediatric/craniofacial, and 41 reconstructive studies. The authors examined bacterial data extracted from studies for patients who did or did not take prophylactic systemic antibiotics for prevention of SSI. Clinical recommendations were provided using level I evidence.

CONCLUSIONS

Surgeons have long been overprescribing systemic antibiotic prophylaxis in plastic and reconstructive surgery. Evidence supports antibiotic prophylaxis to prevent SSI for specific indications and durations. Prolonged antibiotic use has not been linked to reductions in SSIs, and misuse may increase the bacterial diversity of infections. Greater efforts should focus on transitioning from practice-based to pharmacotherapeutic evidence-based medicine.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, II.

The Incidence of Infection Complicating Snakebites in Tropical Australia: Implications for Clinical Management and Antimicrobial Prophylaxis

Objective

To define the incidence of infection following snakebite in tropical Australia and the resulting implications for the routine prescription of prophylactic antibiotics.

Methods

A retrospective study of all individuals presenting to Cairns Hospital, a tertiary referral hospital in tropical Australia, after a snakebite between December 2013 and October 2020.

Results

There were 732 hospitalisations, 720 (98.4%) patients presented within 8 hours of the snakebite, and 29/732 (4.0%) were envenomated. Envenomated patients were more likely to receive empirical antibiotics than nonenvenomated patients (8/29 (27.6%) versus 14/703 (2.0%), p < 0.001), although this was frequently as a bundle of care for critically ill individuals. Superficial skin infection was diagnosed by clinicians in 6/732 (0.8%) patients during their hospitalisation; infection was diagnosed more commonly in envenomated than in nonenvenomated patients (3/29 (10.3%) versus 3/703 (0.4%), p = 0.001). All 3 envenomated individuals diagnosed with infection were believed to have taipan (genus Oxyuranus) bites. Five (83%) of the six patients diagnosed with infection had received empirical antibiotics at presentation; only 1/710 (0.1%) patients who received no antibiotics developed a (superficial) infection.

Conclusion

Infection is a very uncommon complication of snakebite in tropical Australia. Individuals bitten by snakes in tropical Australia should not routinely receive antibiotic prophylaxis.

Antibiotic susceptibility of cultivable microbiota from the oral cavity of captive Bothrops atrox and Bothrops lanceolatus: Implications for the treatment of snakebite-associated infections in the French departments of America

INTRODUCTION

Secondary infection is a frequent complication after bites by Bothrops atroxin French Guiana or B. lanceolatus in Martinique. Knowledge of the bacteria present in snake mouths is a valuable aid for determining probabilistic antibiotherapy after Bothrops bite. The objectives of this study were to describe the cultivable bacteria of the oral microbiota of the specimens of B. atrox and B. lanceolatus kept in captivity, and to study their susceptibility to antibiotics.

METHODS

Fifteen B. atrox and 15 B. lanceolatus were sampled. Bacterial cultures were performed and each morphotype on plates was identified using MALDI-TOF mass spectrometry. Antibiotic susceptibility was studied using the agar disk diffusion method, with possible determination of the MICs.

RESULTS

One hundred and twenty-two isolates were identified: 52 isolates and 13 species in B. atrox, 70 isolates and 23 species in B. lanceolatus. The main species were Providencia rettgeri, Morganella morganii, Pseudomonas aeruginosa, Staphylococcus xylosus, and Paeniclostridium sordellii (only in B. lanceolatus mouths). For B. atrox, 96% of isolates were susceptible to piperacillin/tazobactam, cefepime, imipenem and meropenem, 94% to ciprofloxacin and 76% to cefotaxime and ceftriaxone. For B. lanceolatus, 97% of isolates were susceptible to meropenem, 96% to cefepime, 93% to imipenem and piperacillin/tazobactam, 80% to ciprofloxacin, and 75% to cefotaxime and ceftriaxone. Many isolates were resistant towards amoxicillin/clavulanate.

CONCLUSION

Among currently recommended antibiotics, cefepime and piperacillin/tazobactam seem more suitable than cefotaxime or ceftriaxone in the event of a Bothrops bite. Ciprofloxacin may also be considered for B. atrox.

Inflammatory Profile Associated with Secondary Infection from Bothrops atrox Snakebites in the Brazilian Amazon

Bothrops snakebite envenomation (SBE) is consider an important health problem in Brazil, where Bothrops atrox is mainly responsible in the Brazilian Amazon. Local effects represent a relevant clinical issue, in which inflammatory signs and symptoms in the bite site represent a potential risk for short and long-term disabilities. Among local complications, secondary infections (SIs) are a common clinical finding during Bothrops atrox SBE and are described by the appearance of signs such as abscess, cellulitis or necrotizing fasciitis in the affected site. However, the influence of SI in the local events is still poorly understood. Therefore, the present study describes for the first time the impact of SBE wound infection on local manifestations and inflammatory response from patients of Bothrops atrox SBE in the Brazilian Amazon. This was an observational study carried out at the Fundação de Medicina Tropical Dr. Heitor Vieira Dourado, Manaus (Brazil), involving victims of Bothrops SBE. Clinical and laboratorial data were collected along with blood samples for the quantification of circulating cytokines and chemokines before antivenom administrations (T0) and 24 h (T1), 48 h (T2), 72 h (T3) and 7 days after (T4). From the 94 patients included in this study, 42 presented SI (44.7%) and 52 were without SI (NSI, 55.3%). Patients classified as moderate envenoming presented an increased risk of developing SI (OR = 2.69; CI 95% = 1.08-6.66, p = 0.033), while patients with bites in hands showed a lower risk (OR = 0.20; CI 95% = 0.04-0.96, p = 0.045). During follow-up, SI patients presented a worsening of local temperature along with a sustained profile of edema and pain, while NSI patients showed a tendency to restore and were highlighted in patients where SI was diagnosed at T2. As for laboratorial parameters, leukocytes, erythrocyte sedimentation ratio, fibrinogen and C-reactive protein were found increased in patients with SI and more frequently in patients diagnosed with SI at T3. Higher levels of circulating IL-2, IL-10, IL-6, TNF, INF-γ and CXCL-10 were observed in SI patients along with marked correlations between these mediators and IL-4 and IL-17, showing a plurality in the profile with a mix of Th1/Th2/Th17 response. The present study reports for the first time the synergistic effects of local infection and envenoming on the inflammatory response represented by local manifestations, which reflected on laboratorial parameters and inflammatory mediators and thus help improve the clinical management of SI associated to Bothrops SBE.

A long-term observational study of paediatric snakebite in Kilifi County, south-east Kenya

INTRODUCTION

Estimates suggest that one-third of snakebite cases in sub-Saharan Africa affect children. Despite children being at a greater risk of disability and death, there are limited published data. This study has determined the: population-incidence and mortality rate of hospital-attended paediatric snakebite; clinical syndromes of snakebite envenoming; and predictors of severe local tissue damage.

METHODS

All children presenting to Kilifi County Hospital, Kenya with snakebite were identified through the Kilifi Health and Demographic Surveillance System (KHDSS). Cases were prospectively registered, admitted for at least 24-hours, and managed on a paediatric high dependency unit (HDU). Households within the KHDSS study area have been included in 4-monthly surveillance and verbal autopsy, enabling calculation of population-incidence and mortality. Predictors of severe local tissue damage were identified using a multivariate logistic regression analysis.

RESULTS

Between 2003 and 2021, there were 19,606 admissions to the paediatric HDU, of which 584 were due to snakebite. Amongst young children (≤5-years age) the population-incidence of hospital-attended snakebite was 11.3/100,000 person-years; for children aged 6-12 years this was 29.1/100,000 person-years. Incidence remained consistent over the study period despite the population size increasing (98,967 person-years in 2006; and 153,453 person-years in 2021). Most cases had local envenoming alone, but there were five snakebite associated deaths. Low haemoglobin; raised white blood cell count; low serum sodium; high systolic blood pressure; and an upper limb bite-site were independently associated with the development of severe local tissue damage.

CONCLUSION

There is a substantial burden of disease due to paediatric snakebite, and the annual number of cases has increased in-line with population growth. The mortality rate was low, which may reflect the species causing snakebite in this region. The identification of independent predictors of severe local tissue damage can help to inform future research to better understand the pathophysiology of this important complication.

Clinical Profile and Pharmacological Management of Snakebites in Community Care Units: A Retrospective Study Using Two Military Hospital Databases in South Thailand

Snakebite envenoming is an occupational hazard in remote rural areas of South Thailand, where the highest incidence of snakebites is reported. In this work, a hospital-based retrospective study of snakebite patients from 2012 to 2022 at Fort Wachirawut Hospital and Fort Thepsatrisrisunthon Hospital, located in Nakhon Si Thammarat province, Thailand was conducted. Data from the laboratory investigation, physical examinations of snakebite victims, and clinical management, including pharmacological and non-pharmacological treatments, were evaluated. A total of 54 snakebite victims were included. The median age of patients was 49 years (IQR, 28 to 63). Males accounted for 74.1% of all participants. The majority of patients were bitten by Malayan pit vipers (68.5%), followed by unidentified snakes (18.5%), other non-venomous snakes (7.4%), and cobras (5.6%). The most common clinical manifestations were swelling (90.2%) and local pain (73.2%). One patient experienced respiratory failure following an envenoming by an unidentified venomous snake. No deaths were observed in this study. In total, 24 patients received antivenom administration (44.4%), most of whom were from Fort Wachirawut Hospital. Patients who were administered antivenom showed a median admission duration of three days (IQR, 3 to 4), compared with two days (IQR, one to three) for those who did not receive antivenom treatment (p < 0.001). In addition, paracetamol and prophylactic antibiotics, namely, amoxicillin-clavulanate and dicloxacillin, were the most common pharmacotherapies following snakebites. Overall, it was observed that these two community hospitals undertook appropriate clinical management under the standard guidelines for snakebite patients. This might be due to the effective emergency management, facilities, and clinical consultations. Finally, the management process in the medical teams also plays a crucial role in minimizing the severity of snakebite outcomes.

Treatment of a Snakebite Injury With Secondary Bacterial Infection: A Case Study

BACKGROUND

Pit viper snakebites are challenging as they often cause tissue injury and secondary bacterial infection that may impair full recovery of the affected limb. We describe the evolution of a snakebite injury with secondary infection and the use of specialized dressings to achieve tissue repair and complete closure of the wound.

CASE

Ms E., a 45-year-old woman, was bitten by a pit viper that began as a small lesion and progressed to necrosis, cellulitis, edema, and hyperemia of the perilesional skin, local inflammation, and infection. We implemented a combination of topical hydrogel therapy with calcium alginate and hydrofiber with 1.2% silver to promote autolytic debridement, combat local infection, and provide a moist wound environment. The wound required daily local treatment for 2 months due to extensive tissue damage, combined with the proteolytic action of the bothropic venom.

CONCLUSION

The care of wounds caused by snakebites is a challenge for the health care team due to tissue loss resulting from the action of the venom and secondary bacterial infection. Close follow-up with the use of systemic antibiotics and topical therapies proved effective in minimizing tissue loss in this case.

Prospecting Local Treatments Used in Conjunction with Antivenom Administration Following Envenomation Caused by Animals: A Systematic Review

Envenomation caused by venomous animals may trigger significant local complications such as pain, edema, localized hemorrhage, and tissue necrosis, in addition to complications such as dermonecrosis, myonecrosis, and even amputations. This systematic review aims to evaluate scientific evidence on therapies used to target local effects caused by envenomation. The PubMed, MEDLINE, and LILACS databases were used to perform a literature search on the topic. The review was based on studies that cited procedures performed on local injuries following envenomation with the aim of being an adjuvant therapeutic strategy. The literature regarding local treatments used following envenomation reports the use of several alternative methods and/or therapies. The venomous animals found in the search were snakes (82.05%), insects (2.56%), spiders (2.56%), scorpions (2.56%), and others (jellyfish, centipede, sea urchin-10.26%). In regard to the treatments, the use of tourniquets, corticosteroids, antihistamines, and cryotherapy is questionable, as well as the use of plants and oils. Low-intensity lasers stand out as a possible therapeutic tool for these injuries. Local complications can progress to serious conditions and may result in physical disabilities and sequelae. This study compiled information on adjuvant therapeutic measures and underscores the importance of more robust scientific evidence for recommendations that act on local effects together with the antivenom.

Clinical aspects of snakebite envenoming and its treatment in low-resource settings

There is increasing recognition of the public health importance of snakebite envenoming. Worldwide annual incidence is likely to be 5 million bites, with mortality exceeding 150 000 deaths, and the resulting physical and psychological morbidity leads to substantial social and economic repercussions. Prevention through community education by trained health workers is the most effective and economically viable strategy for reducing risk of bites and envenoming. Clinical challenges to effective treatment are most substantial in rural areas of low-resource settings, where snakebites are most common. Classic skills of history taking, physical examination, and use of affordable point-of-care tests should be followed by monitoring of evolving local and systemic envenoming. Despite the profusion of new ideas for interventions, hyperimmune equine or ovine plasma-derived antivenoms remain the only specific treatment for snakebite envenoming. The enormous interspecies and intraspecies complexity and diversity of snake venoms, revealed by modern venomics, demands a radical redesign of many current antivenoms.

The Effectiveness of Antibiotics in Managing Bacterial Infections on Bite Sites following Snakebite Envenomation

Snakebite envenomation (SBE) is a life-threatening medical emergency with a high mortality rate. Common secondary complications following SBE, such as wound infections, are significant due to their impact on worsening local tissue damage and causing systemic infection. Antivenoms are not effective to treat wound infections following SBE. Moreover, in several rural clinical settings, broad-spectrum antibiotics are often used without clear guidelines or based on limited laboratory data, resulting in undesirable side effects and exacerbated treatment costs. Therefore, robust antibiotic strategies should be developed to tackle this critical issue. Currently, there is limited information available on the bacterial profiles of SBE-induced infections and antibiotic susceptibility. Hence, it is essential to improve the knowledge of bacterial profiles and their antibiotic sensitivity in SBE victims to develop better treatment strategies. This study aimed to address this issue by examining the bacterial profiles of SBE victims with a specific focus on Russell's viper envenomation. The most frequently found bacteria in the bites of SBE victims were Staphylococcus aureus, Klebsiella sp., Escherichia coli, and Pseudomonas aeruginosa. Linezolid, clindamycin, colistin, meropenem, and amikacin were some of the most effective antibiotics for commonly grown bacteria in SBE victims. Similarly, ciprofloxacin, ampicillin, amoxiclave, cefixime, and tetracyclin were the least effective antibiotics for common bacteria found in the wound swabs of SBE victims. These data provide robust guidance for infection management following SBE and offer useful insights to aid in designing effective treatment protocols for SBE with serious wound infections in rural areas where laboratory facilities may not be readily available.

Perceptions of nurses regarding the management of snakebite envenomations: Limits and possibilities

Snakebites can be caused by harmless or venomous snakes and, according to their severity and frequency, can be considered events of medical importance. In health facilities in remote areas, nurses work in the first line of care of patients that are victims of these envenomations. The aim was to discover the perception of nurses regarding the management of snakebites, its limitations and possibilities, with a view to professional empowerment in the context of primary health care. This is exploratory and descriptive research, with a qualitative approach, developed at FMT-HVD in Manaus, Amazonas state, Brazil, in the year 2021. The participants were nurses who work in basic health units in the municipalities of Careiro da Várzea, Ipixuna and Boa Vista do Ramos in the state of Amazonas. For data collection, the focus group strategy was adopted. Thematic content analysis was employed, which was carried out in the stages of pre-analysis; exploration or coding of the material; treatment of the results, inference and interpretation. After processing the data obtained, four topics emerged from the coding: Topic 1 - limitations in the primary care. Topic 2 - the need for infrastructure and personnel. Topic 3 - the need for continuing education. Topic 4 - the perception of training regarding the management of snakebite envenomations. The results showed a lack of antivenom in the healthcare units where nurses work. Another aspect highlighted by the nurses is the absence of a doctor in situ to perform the primary care or out of hours care in the units. The nurses' perceptions regarding the management of snakebite envenomations revealed the existence of failures in relation to the subject, such as the lack of antivenom, poor infrastructure in the units and the lack of a doctor, which must be solved, since the nurses are the most active professionals in primary health care, in addition to the high incidence of snakebite envenomations in the Brazilian Amazon.

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.

A rational in silico approach to identify inhibitors of Batroxrhagin from Bothrops atrox

Bothrops atrox venom comprises several types of bioactive molecules, enzymatic and non-enzymatic, among those, Batroxrhagin is the most predominant SVMP P-III enzyme, which are responsible for induction of local and systemic hemorrhage and muscle fibers damage, impairing regeneration. Due to great difficulties in establishing an antibothropic drug, new strategies must be addressed to achieve a more effective and efficient treatment. There are no studies of specific catalytic inhibitors of Batroxrhagin. However, there are in vitro studies that have described similar metalloprotease inhibitors. The inhibitor batimastat was used as a leading compound for the search and selection of similar candidates. This molecule is widely cited as a metalloprotease inhibitor and as an antimetastatic. In addition to batimastat-like molecules, four other reported metalloprotease inhibitors were included to compose the study's positive control group. Hence, 580 molecules were tested. The three-dimensional structure of B. atrox Batroxrhagin was predicted based on homologous structures using Modeller 9.20. Molecular docking calculation was performed using Autodock 4.2 and molecular surfaces and interactions were analyzed using Biovia/Discovery Studio 2017. Among 576 molecules, 42 similar to batismast resulted in a better energy of interaction than all positive controls, including batimastat itself. The batimastat-like molecules with lowest energy and positive controls were subjected to molecular dynamics for 30 ns in Gromacs 2019.4. This batimastat-like molecule produced better stability among all the Batroxrhagin-ligand complexes analyzed. Overall, the proposed compounds present justifiable evidence for future in vitro tests aiming to inhibit Batroxrhagin. Communicated by Ramaswamy H. Sarma.

Outcomes in intervention research on snakebite envenomation: a systematic review

INTRODUCTION

A core outcome set (COS) is a minimal list of consensus outcomes that should be used in all intervention research in a specific domain. COS enhance the ability to undertake meaningful comparisons and to understand the benefits or harms of different treatments. A first step in developing a COS is to identify outcomes that have been used previously. We did this global systematic review to provide the foundation for development of a region-specific COS for snakebite envenomation.  Methods: We searched 15 electronic databases, eight trial registries, and reference lists of included studies to identify reports of relevant trials, protocols, registry records and systematic reviews. We extracted verbatim data on outcomes, their definitions, measures, and time-points. Outcomes were classified as per an existing outcome taxonomy, and we identified unique outcomes based on similarities in the definition and measurement of the verbatim outcomes.

RESULTS

We included 107 records for 97 studies which met our inclusion criteria. These reported 538 outcomes, with a wide variety of outcome measures, definitions, and time points for measurement. We consolidated these into 88 unique outcomes, which we classified into core areas of mortality (1, 1.14 %), life impact (6, 6.82%), resource use (15, 17.05%), adverse events (7, 7.95%), physiological/clinical (51, 57.95%), and composite (8, 9.09%) outcomes. The types of outcomes varied by the type of intervention, and by geographic region. Only 15 of the 97 trials (17.04%) listed Patient Related Outcome Measures (PROMS).

CONCLUSION

Trials evaluating interventions for snakebite demonstrate heterogeneity on outcomes and often omit important information related to outcome measurement (definitions, instruments, and time points). Developing high quality, region-specific COS for snakebite could inform the design of future trials and improve outcome reporting. Measurement of PROMS, resource use and life impact outcomes in trials on snakebite remains a gap.

Validation of a Culturally Relevant Snakebite Envenomation Clinical Practice Guideline in Brazil

Snakebite envenoming (SBE) is a neglected tropical disease with significant global morbidity and mortality. Even when antivenom is available in low-resource areas, health workers do not receive adequate training to manage SBEs. This study aims to develop and validate a clinical practice guideline (CPG) for SBE management across Brazil. A panel of expert judges with academic and/or technical expertise in SBE management performed content validation. The content validity index (CVI) score was 90% for CPG objectives, 89% for structure and presentation and 92% for relevance and classified the CPG as valid. A semantic validation was performed by analyzing focus group discussions with doctors and nurses from three municipalities of the Brazilian Amazon, after a 5-day meeting during which the CPG was presented. Two central themes emerged: knowledge acquired during the meeting and recommendations for improving the CPG. Based on these results, the CPG was revised into a final version. This study presents the successful development and validation process of a CPG for SBE management, which is targeted to a specific low-resource, high-burden setting. This development and validation process can be adapted to other settings and/or other neglected tropical diseases.

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.

Characteristics and significance of "green snake" bites in Myanmar, especially by the pit vipers Trimeresurus albolabris and Trimeresurus erythrurus

Snakebite is an important problem in Myanmar. Regionally, bites by Eastern Russell's vipers, Daboia siamensis (Viperidae, Viperinae), and monocled cobras, Naja kaouthia are considered medically important, but those categorised as "green snake" bites are not. However, these may include bites by green pit vipers, Trimeresurus spp. (Viperidae, Crotalinae) for which no antivenom is available in Myanmar. Elsewhere in Southeast Asia, these snakes are reported to cause local and systemic envenoming. As part of the Myanmar Snakebite Project, prospective case data were collected over 3 years from five hospitals in the Mandalay region. These included 3803 snakebite cases reported from Mandalay region. Of these, 355 were listed as bites by a witnessed green-coloured snake. In 22 cases, the snakes responsible were retained and preserved, then expertly identified; 21 were medically important white-lipped pit vipers (Trimeresurus albolabris), and one as an Asian vine snake, Ahaetulla prasina (Colubridae, Ahaetuliinae) which is not of medical importance. Among confirmed Trimeresurus albolabris bites, 15/21 developed swelling of the bitten limb, and 3/21 coagulopathy, defined as a positive 20-min whole blood clotting test (20WBCT). None developed necrosis, blistering, thrombocytopenia or acute kidney injury (AKI). Of the remaining 333 patients bitten by green snakes that were not specifically identified, 241 (72%) developed swelling of the bitten limb, and 62 (19%) coagulopathy. AKI occurred in 21/333 patients, but only one required dialysis. At least 10/21 of the cases with AKI in this study were more likely to represent bites from Trimeresurus spp. than D. siamensis because the snake responsible was brought into the hospital, examined and described by the treating physician as "green-coloured". This study describes a previously unpublished case of AKI from envenoming by T. erythrurus in Yangon, and reviews cases of AKI following bites by this species and T. albolabris in Myanmar. This confirms that, at least on rare occasions, Trimeresurus spp. envenoming can cause AKI. This has important implications for snakebite management in Myanmar as the finding of local swelling, coagulopathy and AKI is generally considered pathognomonic of D. siamensis envenoming. Further collection of confirmed Trimeresurus spp. bites is required in Myanmar in order better to define the syndrome of envenoming and to assess the possible need for antivenom against Trimeresurus spp. in this country.

Clinical management of snakebite envenoming: Future perspectives

Snakebite envenoming is a major cause of morbidity and mortality in rural communities throughout the tropics. Generally, the main clinical features of snakebites are local swelling, tissue necrosis, shock, spontaneous systemic hemorrhage, incoagulable blood, paralysis, rhabdomyolysis, and acute kidney injury. These clinical manifestations result from complex biochemical venom constituents comprising of cytotoxins, hemotoxins, neurotoxins, myotoxins, and other substances. Timely diagnosis of envenoming and identification of the responsible snake species is clinically challenging in many parts of the world and necessitates prompt and thorough clinical assessment, which could be supported by the development of reliable, affordable, widely-accessible, point-of-care tests. Conventional antivenoms based on polyclonal antibodies derived from animals remain the mainstay of therapy along with supportive medical and surgical care. However, while antivenoms save countless lives, they are associated with adverse reactions, limited potency, and are relatively inefficacious against presynaptic neurotoxicity and in preventing necrosis. Nevertheless, major scientific and technological advances are facilitating the development of new molecular and immunologic diagnostic tests, as well as a new generation of antivenoms comprising human monoclonal antibodies with broader and more potent neutralization capacity and less immunogenicity. Repurposed pharmaceuticals based on small molecule inhibitors (e.g., marimastat and varespladib) used alone and in combination against enzymatic toxins, such as metalloproteases and phospholipase A2s, have shown promise in animal studies. These orally bioavailable molecules could serve as early interventions in the out-of-hospital setting if confirmed to be safe and efficacious in clinical studies. Antivenom access can be improved by the usage of drones and ensuring constant antivenom supply in remote endemic rural areas. Overall, the improvement of clinical management of snakebite envenoming requires sustained, coordinated, and multifaceted efforts involving basic and applied sciences, new technology, product development, effective clinical training, implementation of existing guidelines and therapeutic approaches, supported by improved supply of existing antivenoms.

Les envenimations vipérines en Guyane française

L’OMS classe l’envenimation vipérine comme pathologie négligée. Elle représente un problème de santé publique associé à des taux de mortalité et de morbidité importants. Notre objectif est de faire une mise au point sur les données récentes de la littérature sur l’épidémiologie et la prise en charge de l’envenimation vipérine en Guyane française. La Guyane est un département français presque entièrement recouvert par une forêt tropicale. Elle abrite une herpétofaune très riche comportant notamment les espèces du genre Bothrops (famille des Viperidae) qui provoquent le plus grand nombre de morsures et d’envenimations. La gestion des envenimations vipérines représente un défi de santé publique. En effet, la plupart des envenimations se produisent dans des zones rurales éloignées où l’accès aux soins est le plus compliqué, avec la présence d’un personnel médical peu formé à la prise en charge et l’indisponibilité de l’antivenin, ce qui constitue une véritable perte de chance pour les patients. En conclusion, dans un contexte d’efforts mondiaux visant à réduire l’impact des envenimations vipérines, la coopération internationale et l’engagement des autorités locales de santé et de la société civile sont nécessaires. En Guyane, la mise en place d’une véritable filière de soins et la mise à disposition de l’antivenin dans les structures sanitaires les plus isolées constitueraient un réel progrès sanitaire.

Adjunct treatment in snakebite envenoming: a systematic review of randomised controlled trials

Adjunct therapy in snakebite may be lifesaving if administered appropriately or can be harmful if non-judicious use leads to avoidable delays in administering antivenom. This systematic review analyses the evidence from randomised controlled trials (RCTs) on the efficacy of adjunct treatment administered with antivenom. PubMed, EMBASE, Scopus, Cochrane library and CINAHL were searched for RCTs enrolling patients with snakebite envenoming where a treatment other than antivenom has been assessed for its efficacy within the last 25 y. Fifteen studies met the inclusion criteria. The interventions assessed were categorised as adjunct therapies (heparin or fresh frozen plasma) to reverse haemotoxicity (three studies), antibiotics to prevent local infections (three studies), steroids to reduce local swelling (one study), premedication (adrenaline, steroids and antihistamines, either alone or in combination) to reduce hypersensitivity reactions to antivenom (five studies) and other interventions (three studies). Apart from a beneficial effect of low-dose adrenaline (1:1000, 0.25 ml administered subcutaneously) in preventing antivenom-induced hypersensitivities (OR: 0.54, 95% CI 0.32 to 0.93, two RCTs, 354 participants, moderate certainty evidence) in Sri Lanka, evidence for any other adjunct therapy is either non-existent or needs confirmation by larger better designed trials.

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.

Severe tissue complications in patients of Bothrops snakebite at a tertiary health unit in the Brazilian Amazon: clinical characteristics and associated factors

INTRODUCTION:

Snakebites in the Brazilian Amazon are caused mostly by snakes from the Bothrops genus and envenomated patients may suffer from tissue complications.

METHODS:

This study aimed to identify risk factors for severe tissue complications (STC) in patients with Bothrops snakebite in the Amazonas state, Brazil.

RESULTS:

Snakebites that were classified as severe and affected female patients with comorbidities presented greater risks of developing STCs. In addition, hospitalizations of patients with STC exceeded 5 days.

CONCLUSIONS:

Clinical and epidemiological characteristics can prove essential for assessing the evolution of STC and clinical prognosis of patients with Bothrops snakebites.

Association of cfDNA levels and bothrops envenomation

In the Amazon, around 90% of snakebites are caused by the Bothrops genus. Complications arising from Bothrops envenomations result from the inflammatory and coagulotoxic activities of the venom. The aim of this study was to investigate the potential of cell-free DNA (cfDNA) as a biomarker of severity in Bothrops snakebites. Patients were treated at the Fundação de Medicina Tropical Dr. Heitor Vieira Dourado (FMT-HVD), Manaus, in the Brazilian Amazon. cfDNA plasma levels were measured by amplifying the human telomerase reverse transcriptase (hTERT) sequence using quantitative RT-PCR. Median levels of cfDNA were compared between envenomed and healthy volunteers and among patients presenting different complications, such as renal failure, bleeding and infection. Of the 76 patients included, 82.9% were male, with a mean age of 32.8 years, and envenomations were mainly classified as severe (39.5%). ROC curve analysis showed a good accuracy of cfDNA levels (AUROC of 0.745) in envenomation diagnosis. A correlation analysis using laboratory variables showed positive correlation with lactate dehydrogenase (p = 0.033) and platelet count (p = 0.003). When cfDNA levels were compared with clinical complications, significant statistical differences were only found among individuals with mild and severe pain (p < 0.05). In summary, our results demonstrated that cfDNA levels are sufficiently accurate for discriminating between envenomed and non-envenomed patients, but are not able to distinguish different complications and the level of severity among envenomed patients. Thus, the role of cfDNA in the pathogenesis of the snakebite envenomations needs to be further investigated.

Severe Heloderma spp. envenomation: a review of the literature

Context: Heloderma bites are rare and generally mild, but a few cases can be life threatening. Methods: Description of Heloderma bite was searched in medical literature. Discussion: We present a synthesis of clinical and biomedical effects of envenomation by Heloderma sp. based on 22 well identified cases described in medical literature. Three life-threatening syndromes, concomitant or not, may be involved: (a) angioedema which can lead to respiratory tract obstruction, (b) significant fluid losses due to diarrhea, vomiting and sweating, associated with hypokalemia and sometimes metabolic acidosis, and (c) atrioventricular conduction disorders simulating cardiac ischemia. Conclusion: Heloderma bite are quite rare and generally mild. However, few severe cases may require emergency resuscitation. There is no antivenom, and the treatment is only symptomatic and supportive.

Interventions for the management of snakebite envenoming: An overview of systematic reviews

INTRODUCTION

Snakebite is a neglected tropical disease that leads to more than 120,000 deaths every year. In 2019, World Health Organization (WHO) launched a strategy to decrease its global burden by 2030. There is a range of issues around different interventions for the management of snakebite. Decisions around these interventions should be informed by evidence from systematic reviews (SR).

METHODS

An overview of SRs was conducted by searching 12 electronic databases, PROSPERO, contacting experts and screening the bibliography of included reviews. Screening, data extraction, and quality assessment (through AMSTAR-2) was done by at least two overview authors independently with discrepancies sorted by consensus. A narrative synthesis was conducted.

PRINCIPLE FINDINGS

The overview found 13 completed SRs that has looked at various aspects of management of snakebite envenomation. There was one SR on first aid, nine on effectiveness and safety of snake anti-venom (SAV), two on drugs to prevent adverse reactions due to SAV therapy, and one on surgical interventions for management of snakebite envenomation. All, except one, SR was appraised to have critically low confidence as per AMSTAR-2 Criteria. Evidence base was restricted to few studies for most interventions.

DISCUSSION

High quality evidence from SRs is required to inform guidelines and health system decisions which can bring down the burden of snakebite. The review indicates the need to fund high-quality SRs, evidence gaps and core outcome sets which can inform guideline recommendations, funding priorities for conduct of future trials. Variation in species distribution as well as intra-species variation in venom composition implies the need for conduct of region or, nation or state (sub-national) specific randomised controlled trials and SRs on different SAVs and their dosing regimens.

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.

New insights into snakebite epidemiology in Costa Rica: A retrospective evaluation of medical records

Continuous monitoring of the snakebite envenoming allows elucidating factors that affect its incidence at spatial and temporal scales, and is a great tool to evaluate the proper management of snakebite in health centers. To determine if there have been changes over time in snakebite epidemiology in Costa Rica, we conducted a retrospective study using medical records from six hospitals for the years 2012-2013. A total of 475 snakebite patients were treated at the selected hospital during this period. Most bites occurred during the rainy season and primarily affected young men, mainly farm workers and schoolchildren. About 55% of bites occur in peri-domiciliary environments, although its prevalence varies geographically. Bothrops asper generates the vast majority of envenoming in the country, which is why the main local symptoms registered are edema, pain, and bleeding disorders. The time elapsed until treatment did not explain the degree of severity at admission. However, complications were observed more frequently in patients who took longer to receive treatment. The primary complications were bacterial infections, whereas kidney failure and compartment syndrome documented at very low frequencies. Only one death was recorded, reflecting the low fatality rate exhibited in the country. Hospital treatment included the rapid administration of antivenom and complementary treatment of antibiotics, analgesics, and antihistamines. The application of the latter as prophylactic does not seem to prevent the appearance of mild early adverse reactions, registered in 22.5% of the cases. Morbidity and mortality rates from snakebite have continued to decrease in the country, as a result of the efforts that Costa Rica has made to improve its public health system. Among those efforts, the creation of primary care centers (EBAIS) has reduced the time to treatment in many regions of the country. The Costa Rican experience of using antivenom in primary health care centers and maintaining good medical records could be considered for application in other countries where snakebite is a major health problem.

Bleeding Disorders in Bothrops atrox Envenomations in the Brazilian Amazon: Participation of Hemostatic Factors and the Impact of Tissue Factor

Bleeding is a common hemostatic disorder that occurs in Bothrops envenomations. We evaluated the changes in coagulation, fibrinolysis components, and platelets in Bothrops atrox envenomations with bleeding. This is an observational study with B. atrox snakebite patients (n = 100) treated in Manaus, Brazilian Amazon. Bleeding was recorded on admission and during hospitalization. We found that the platelet count in our patients presented a weak correlation to tissue factor, factor II, and plasminogen. Tissue factor presented weak correlation to factor V, II, D-dimer, plasminogen, alpha 2-antiplasmin, and moderate correlation to fibrinogen and fibrin/fibrinogen degradation product (FDP). Patients with systemic bleeding (n = 20) presented low levels of factor V, II, fibrinogen, plasminogen, and alpha 2-antiplasmin, and high levels of tissue factor and FDP compared to those without bleeding. Patients with only local bleeding (n = 41) and without bleeding showed similar levels of hemostatic factors. Thrombocytopenia was observed mainly in patients with systemic bleeding and increased levels of serum venom. No association was found between venom levels and systemic bleeding, or between venom levels and clinical severity of envenomation. This is the first report that shows the participation of the extrinsic coagulation pathway in the consumption coagulopathy of B. atrox envenomations with systemic bleeding due to tissue factor release.

Correlating Fibrinogen Consumption and Profiles of Inflammatory Molecules in Human Envenomation's by Bothrops atrox in the Brazilian Amazon

Snakebites are considered a major public health problem worldwide. In the Amazon region of Brazil, the snake Bothrops atrox (B. atrox) is responsible for 90% of the bites. These bites may cause local and systemic signs from acute inflammatory reaction and hemostatic changes, and present common hemorrhagic disorders. These alterations occur due the action of hemostatically active and immunogenic toxins which are capable of triggering a wide range of hemostatic and inflammatory events. However, the crosstalk between coagulation disorders and inflammatory reaction still has gaps in snakebites. Thus, the goal of this study was to describe the relationship between the consumption of fibrinogen and the profile of inflammatory molecules (chemokines and cytokines) in evenomations by B. atrox snakebites. A prospective study was carried out with individuals who had suffered B. atrox snakebites and presented different levels of fibrinogen consumption (normal fibrinogen [NF] and hypofibrinogenemia [HF]). Seventeen patients with NF and 55 patients with HF were eligible for the study, in addition to 50 healthy controls (CG). The molecules CXCL-8, CCL-5, CXCL-9, CCL-2, CXCL-10, IL-6, TNF, IL-2, IL-10, IFN-γ, IL-4, and IL-17A were quantified in plasma using the CBA technique at three different times (pre-antivenom therapy [T0], 24 h [T1], and 48 h [T2] after antivenom therapy). The profile of the circulating inflammatory response is different between the groups studied, with HF patients having higher concentrations of CCL-5 and lower IFN-γ. In addition, antivenom therapy seems to have a positive effect, leading to a profile of circulating inflammatory response similar in quantification of T1 and T2 on both groups. Furthermore, these results suggest that a number of interactions of CXCL-8, CXCL-9, CCL-2, IL-6, and IFN-γ in HF patients are directly affected by fibrinogen levels, which may be related to the inflammatory response and coagulation mutual relationship induced by B. atrox venom. The present study is the first report on inflammation-coagulation crosstalk involving snakebite patients and supports the better understanding of envenomation's pathophysiology mechanisms and guides in the search for novel biomarkers and prospective therapies.

Bothrops atrox, the most important snake involved in human envenomings in the amazon: How venomics contributes to the knowledge of snake biology and clinical toxinology

Bothrops atrox snakes are mostly endemic of the Amazon rainforest and is certainly the South American pit viper responsible for most of the snakebites in the region. The composition of B. atrox venom is significantly known and has been used to trace the relevance of the venom phenotype for snake biology and for the impacts in the clinics of human patients involved in accidents by B. atrox. However, in spite of the wide distribution and the great medical relevance of B. atrox snakes, B. atrox taxonomy is not fully resolved and the impacts of the lack of taxonomic resolution on the studies focused on venom or envenoming are currently unknown. B. atrox venom presents different degrees of compositional variability and is generally coagulotoxic, inducing systemic hematological disturbances and local tissue damage in snakebite patients. Antivenoms are the effective therapy for attenuating the clinical signs. This review brings a comprehensive discussion of the literature concerning B. atrox snakes encompassing from snake taxonomy, diet and venom composition, towards clinical aspects of snakebite patients and efficacy of the antivenoms. This discussion is highly supported by the contributions that venomics and antivenomics added for the advancement of knowledge of B. atrox snakes, their venoms and the treatment of accidents they evoke.

Bothrops atrox Snakebite: How a Bad Decision May Lead to a Chronic Disability: A Case Report

Snakebites are a neglected and underestimated global health hazard. In the Brazilian Amazon, Bothrops snakebites are the most prevalent and may lead to severe complications. Here we describe a severe case of Bothrops atrox snakebite that, owing to delayed medical assistance, presented with renal and respiratory failure, compartment syndrome, and tissue necrosis. After several fasciotomy surgeries, the patient survived; however, he showed significant functional disability. Prompt management of snake envenomation would aid in the early diagnosis of local and systemic complications and, consequently, would result in a better functional outcome with improved quality of life.

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.

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.

Serum Procalcitonin Concentration and Its Relationship with Local Manifestations after Snakebites

The local signs and symptoms following snakebites are similar to those of cellulitis caused by bacterial infections. This leads to empirical treatment with antibiotics, which however is not supported by evidence. Procalcitonin (PCT) is a biomarker with good diagnostic accuracy for bacterial infection. We studied serum PCT concentration in 100 patients aged 13 years or more, presenting to the hospital with significant local manifestations (crossing the joint proximal to the bitten wound) within 24 hours after snakebite. The extent and progression of local manifestations were monitored 12 hourly. Baseline PCT measurement was carried out for all patients and measurement was repeated 12 hourly only in those patients with progressive local manifestations. The median interqartile range PCT concentration did not differ significantly by the severity of local manifestation at presentation (Grade 2 = 0.28 [0.26-0.30]; Grade 3 = 0.28 [0.26-0.32]; Grade 4 = 0.27 [0.26-0.32] ng/mL; P = 0.15). Furthermore, we did not observe an increase in PCT concentration on serial estimation in those with progressive local manifestation (0.28, 0.29, and 0.29 ng/mL) over 36 hours. These observations suggest that the local manifestations following snakebites were not caused by bacterial infection.

Descriptive epidemiology of snakebites in the Veraguas province of Panama, 2007-2008

Background

Panama has the highest incidence of snakebites in Central America, however, few studies have looked at the epidemiology of human snakebites in Panama.

Methods

This retrospective, single-center study reviewed individuals who sustained a snakebite from 2007-2008. Demographic data, disease severity, species of snake, treatment, infectious complications and antibiotic usage were collected from the hospital records.

Results

Data were collected over a 2-y period, with a total of 390 records of snakebites. Bothrops asper was responsible for 43.8% of cases and the majority of the cases occurred during the rainy season. The majority of bites (74.7%) occurred on the hands, feet or toes. Antivenom was used in 55% of patients and 67% of patients received tetanus toxoid. Only 8.7% of individuals presented to the hospital within 1 h of envenomation and more than 25% presented >6 h after envenomation.

Conclusions

B. asper is responsible for the majority of snakebites in the Veraguas province of Panama. Snakebites tend to occur during the rainy season, with the majority of bites occurring on the feet. Several management factors need to improve in Panama: time to presentation, which is prolonged in the majority of cases, and antivenom, antibiotic and tetanus toxoid delivery should be standardized to optimize care.

"Bad things come in small packages": predicting venom-induced coagulopathy in Bothrops atrox bites using snake ontogenetic parameters

Introduction: Snake venom composition shows significant inter- and intra-species variation. In the case of the viperid species Bothrops atrox, responsible for the majority of snakebites in the Amazon region, geographical and ontogenetic variables affect venom composition, with ecological and medical implications. Previous studies had shown that venom from neonate and juvenile Bothrops specimens have a higher in vitro coagulant activity. The aim of this investigation was to assess the association of clinical outcomes, such as venom-induced coagulopathy and local complications, with B. atrox ontogenetic variables.Methods: This study explored the relationship between some clinical parameters in patients suffering envenomations by B. atrox in the Amazon and several morphometric parameters of the snake specimens causing the bites.Results: There were 248 specimens confirmed as agents of envenomation, mostly female snakes (70.5%) and classified as juveniles (62.7%). Patients bitten by neonates compared to adult snakes [OR = 2.70 (95%CI 1.15-6.37); p = .021] and by snakes with white tail tip [OR = 1.98 (95%CI 1.15-3.41); p = .013] were more likely to develop coagulopathy. Time from patient admission to the unclottable blood reversion was not affected by the snake gender (p = .214) or age (p = .254). Patients bitten by neonate (p = .024) or juvenile snakes (p < .0001) presented a lower frequency of moderate to severe edema, as compared to those bitten by adult snakes. In agreement with experimental observations, patients bitten by neonates and by snakes with a white tail tip were more likely to develop coagulopathy than those bitten by adult snakes. In contrast, envenomations by adult snakes were associated with a higher incidence of severe local edema.Conclusion: Despite these variations, no difference was observed in the time needed to recover blood clotting in these patients after Bothrops antivenom administration.

Bothrops snakebites in the Amazon: recovery from hemostatic disorders after Brazilian antivenom therapy

Introduction: Bothrops atrox snakebites are a major public health problem in the Amazon region and also cause hemostatic disorders. In this study, we assessed the recovery from hemostatic disorders in Bothrops snakebite patients after being given antivenom therapy.Methods: This is a prospective study of Bothrops snakebite patients (n = 100) treated at the Fundação de Medicina Tropical Dr. Heitor Vieira Dourado, Manaus, Brazilian Amazon, between January 2016 and December 2017. Blood samples were taken for the measurement of venom concentrations, platelets, clotting time and factors of patients on admission, 12, 24 and 48 h after antivenom therapy, and taken again on discharge. The presence of systemic bleeding was recorded during the follow-up.Results: On admission, systemic bleeding was observed in 14% of the patients. Thrombocytopenia was noted in 10% of the patients. A total of 54% of the patients presented unclottable blood with low levels of fibrinogen and alpha 2-antiplasmin, and high levels of fibrin/fibrinogen degradation product (FDP) and D-dimers. Unclottable blood and systemic bleeding were overcome in most patients 12 h after the antivenom therapy. Three patients developed systemic bleeding 48 h after antivenom therapy. Levels of fibrinogen and alpha 2-antiplasmin, FDP and D-dimer returned to normal around 48 h after the treatment or on discharge. The frequency of thrombocytopenia with high mean platelet volume increased in the first 24 h after antivenom therapy, and decreased on discharge. Bothrops venom levels in patients decreased 12 h after antivenom therapy and were not correlated with coagulation and fibrinolytic parameters. There were no deaths.Conclusion: Laboratorial parameters of coagulopathy returned to normal values within 48 h after the antivenom therapy until discharge. A few patients still presented bleeding signs within 48 h after beginning antivenom therapy. However, the Brazilian antivenom was able to overcome the hemostatic disorders in these cases of envenomation.

Expression of an scFv antibody fragment in Nicotiana benthamiana and in vitro assessment of its neutralizing potential against the snake venom metalloproteinase BaP1 from Bothrops asper

Human accidents with venomous snakes represent an overwhelming public health problem, mainly in rural populations of underdeveloped countries. Their high incidence and the severity of the accidents result in 81,000 to 138,000 deaths per year. The treatment is based on the administration of purified antibodies, produced by hyper immunization of animals to generate immunoglobulins (Igs), and then obtained by fractionating hyper immune plasma. The use of recombinant antibodies is an alternative to conventional treatment of snakebite envenoming, particularly the Fv fragment, named the single-chain variable fragment (scFv). We have produced recombinant single chain variable fragment scFv against the venom of the pit viper Bothrops asper at high levels expressed transiently and stably in transgenic plants and in vitro cultures that is reactive to BaP1 (a metalloproteinase from B. asper venom). The yield from stably transformed plants was significantly (p > 0.05) higher than the results in from transient expression. In addition, scFvBaP1 yields from systems derived from stable transformation were: transgenic callus 62 μg/g (±2); biomass from cell suspension cultures 83 μg/g (±0.2); culture medium from suspensions 71.75 mg/L (±6.18). The activity of scFvBaP1 was confirmed by binding and neutralization of the fibrin degradation induced by BnP1 toxins from B. neuwiedi and by Atroxlysin Ia from B. atrox venoms. In the present work, we demonstrated the potential use of plant cells to produce scFvBaP1 to be used in the future as a biotechnological alternative to horse immunization protocols to produce anti-venoms to be used in human therapy against snakebites.

Low accuracy of microscopic hematuria in detecting coagulopathy from Bothrops pit viper bites, Brazilian Amazon

Introduction: The common lancehead snakes (Bothrops atrox) are responsible for up to 90% of snakebites in the Amazon, especially in remote areas. The prevalence of microhematuria is similar to that of coagulopathy in B. atrox envenomation in the Amazon. Thus, this study aimed to assess the reliability of microhematuria as an inexpensive and simple alternative to detect snake-induced consumption coagulopathy. Methods: We analyzed samples from patients with confirmed B. atrox envenomation in terms of plasma fibrinogen and microhematuria (>3 red blood cells per high power field) in order to access the reliability of microhematuria to detect snakebite-induced coagulopathy, within 12 hours from admission. Results: A total of 186 patients were recruited. From the total, 85.5% of patients had hypofibrinogenemia and only about 50% (n = 94) had a microscopic examination of urine within 12 hours where microhematuria was present in 39 (41.5%). Diagnostic performance showed 38.6% sensitivity and 36.4% specificity (cutpoint 200 mg/dL). No clear association was seen between microhematuria and hypofibrinogenemia (r: -0.10; p: .34). Conclusion: In this study, microhematuria presented poor diagnostic performance to detect coagulopathy. Further studies are necessary to screen inexpensive and simple alternative diagnostic tools.

Factors Associated with Systemic Bleeding in Bothrops Envenomation in a Tertiary Hospital in the Brazilian Amazon

Bothrops snakebites usually present systemic bleeding, and the clinical–epidemiological and laboratorial factors associated with the development of this manifestation are not well established. In this study, we assessed the prevalence of Bothrops snakebites with systemic bleeding reported at the Fundação de Medicina Tropical Dr. Heitor Vieira Dourado, in Manaus, Amazonas State, Brazil, and the clinical–epidemiological and laboratorial factors associated with systemic bleeding. This is an observational, cross-sectional study carried out between August, 2013 and July, 2016. Patients who developed systemic bleeding on admission or during hospitalization were considered cases, and those with non-systemic bleeding were included in the control group. Systemic bleeding was observed in 63 (15.3%) of the 442 Bothrops snakebites evaluated. Bothrops snakebites mostly occurred in males (78.2%), in rural areas (89.0%) and in the age group of 11 to 30 years old (40.4%). It took most of the patients (59.8%) less than 3 h to receive medical assistance. Unclottable blood (AOR = 3.11 (95% CI = 1.53 to 6.31; p = 0.002)) and thrombocytopenia (AOR = 4.52 (95% CI = 2.03 to 10.09; p < 0.001)) on admission were independently associated with systemic bleeding during hospitalization. These hemostatic disorders on admission increase the chances of systemic bleeding during hospitalization. Prospective studies are needed to clarify the pathophysiology of systemic bleeding in Bothrops snakebites in the Amazon region.