Primary closure of human bite losses of the lip.

Human bite injuries of the lip have, because of the potentially contaminated nature of the wounds, been managed by delayed repair after an interval of about 3 months or more when the infection was controlled and the wound healed. On the contrary, from 1985 to 1990, at a plastic surgery unit in Nigeria, a developing country, 37 patients with human bite losses of the lip were managed by an aggressive approach utilizing (1) a 5-day course of antibiotics locally known to be effective against bacterial flora and (2) immediate surgical operation employing the diamond wedge excision method under local anesthesia with direct wound closure. The results have been so favorable that this method of management of human bite injuries is considered a treatment advance.     

Early rotation of a cross-lip flap to repair a defect caused by a human bite.

A case is presented of loss of half of the lower lip from a human bite. An Estlander flap was used on the fifth day for reconstruction, with no infection and a good result. This shows the advantage of a "delayed primary closure" in some of these badly contaminated wounds.     

Bacteriology of human bite wound infections

This study was designed to define the bacteriology of infected soft-tissue wounds from human bites, and to compare this with the bacteriology of infected animal bites in humans as determined in previous studies. The specimens were collected from 57 patients presenting to emergency rooms at 12 locations around the country. Three hundred and eighty organisms were isolated (224 aerobes and 156 anaerobes), for an average of 6.6 per specimen. The most prevalent anaerobes recovered were Prevotella spp. (34%), while streptococci comprised 44% of all aerobic organisms, over half of which were in the "Streptococcus milleri" group, particularly S. anginosus. The study demonstrated that the pathogens in human bite infections differ considerably from those present in animal bites.     

Mosquito saliva causes enhancement of West Nile virus infection in mice

West Nile virus (WNV) is transmitted to vertebrate hosts primarily by infected Culex mosquitoes. Transmission of arboviruses by the bite of infected mosquitoes can potentiate infection in hosts compared to viral infection by needle inoculation. Here we examined the effect of mosquito transmission on WNV infection and systematically investigated multiple factors that differ between mosquito infection and needle inoculation of WNV. We found that mice infected with WNV through the bite of a single infected Culex tarsalis mosquito exhibited 5- to 10-fold-higher viremia and tissue titers at 24 and 48 h postinoculation and faster neuroinvasion than mice given a median mosquito-inoculated dose of WNV (10(5) PFU) by needle. Mosquito-induced enhancement was not due to differences in inoculation location, because additional intravenous inoculation of WNV did not enhance viremia or tissue titers. Inoculation of WNV into a location where uninfected mosquitoes had fed resulted in enhanced viremia and tissue titers in mice similar to those in mice infected by a single infected mosquito bite, suggesting that differences in where virus is deposited in the skin and in the virus particle itself were not responsible for the enhanced early infection in mosquito-infected mice. In addition, inoculation of mice with WNV mixed with salivary gland extract (SGE) led to higher viremia, demonstrating that mosquito saliva is the major cause of mosquito-induced enhancement. Enhanced viremia was not observed when SGE was inoculated at a distal site, suggesting that SGE enhances WNV replication by exerting a local effect. Furthermore, enhancement of WNV infection still occurred in mice with antibodies against mosquito saliva. In conclusion, saliva from C. tarsalis is responsible for enhancement of early WNV infection in vertebrate hosts.     

Generation of Genetically Modified Organotypic Skin Cultures Using Devitalized Human Dermis

Organotypic cultures allow the reconstitution of a 3D environment critical for cell-cell contact and cell-matrix interactions which mimics the function and physiology of their in vivo tissue counterparts. This is exemplified by organotypic skin cultures which faithfully recapitulates the epidermal differentiation and stratification program. Primary human epidermal keratinocytes are genetically manipulable through retroviruses where genes can be easily overexpressed or knocked down. These genetically modified keratinocytes can then be used to regenerate human epidermis in organotypic skin cultures providing a powerful model to study genetic pathways impacting epidermal growth, differentiation, and disease progression. The protocols presented here describe methods to prepare devitalized human dermis as well as to genetically manipulate primary human keratinocytes in order to generate organotypic skin cultures. Regenerated human skin can be used in downstream applications such as gene expression profiling, immunostaining, and chromatin immunoprecipitations followed by high throughput sequencing. Thus, generation of these genetically modified organotypic skin cultures will allow the determination of genes that are critical for maintaining skin homeostasis.     

Wound fluid bacterial levels exceed tissue bacterial counts in controlled porcine partial-thickness burn infections

In the present study, an established controlled burn wound model was used to test the hypothesis that controlled surface contamination with is capable of generating a noninvasive method for the creation of a reproducible deep tissue burn wound infection. Using a liquid tight-wound chamber in Yorkshire pigs, partial-thickness burns were inoculated with saline-immersed for 24 hours. Noninoculated burns and unwounded skin immersed in normal saline served as controls. Bacterial cultures of wound fluid were performed daily, and tissue biopsies for bacteriological and histological evaluations were performed on days 1, 3, and 5. was only recovered from -inoculated wounds (tissue and fluid), whereas all controls contained endogenous only. The number of colony-forming units per gram of wound tissue did not correlate with the bacterial counts found in the overlying wound fluid for any wounds. Fluid counts were consistently higher than tissue counts by two logs. -inoculated wounds showed three times deeper tissue destruction than control wounds. Obtaining consistently deep tissue colonization without cross-contamination among wounds, this study introduces a noninvasive model for controlled burn wound infection suitable for future investigations regarding the efficacy of topical antibiotic wound treatment in experimental burns.     

Application of decellularized human reticular allograft dermal matrix promotes rapid re-epithelialization in a diabetic murine excisional wound model

Background aimsThe treatment and care of human wounds represent an enormous burden on the medical system and patients alike. Chronic or delayed healing wounds are characterized by the inability to form proper granulation tissue, followed by deficiencies in keratinocyte migration and wound re-epithelialization, leading to increased likelihood of infection and poor wound outcomes. Human reticular acellular dermal matrix (HR-ADM) is one type of tissue graft developed to enhance closure of delayed healing wounds that has demonstrated clinical utility through accelerating closure of lower extremity diabetic ulcers, but the mechanisms underlying this clinical success are not well understood.MethodsThe authors utilized a diabetic murine splinted excisional wound model to investigate the effects of HR-ADM application on wound closure.ResultsThe authors demonstrate that application of HR-ADM served as a dermal scaffold and promoted rapid re-epithelialization and keratinocyte proliferation, resulting in accelerated wound closure while minimizing granulation tissue formation. HR-ADM-applied wounds also demonstrated evidence of cellular infiltration, neovascularization and collagen remodeling by the host organism.ConclusionsThese data suggest that HR-ADM supports epidermal closure in delayed healing wounds and remodeling of the matrix into host tissue, lending further support to the clinical success of HR-ADM described in clinical reports.     

Management of human bite injuries of the hand.

On the basis of experience at the Ottawa Civic Hospital over the past 10 years, a classification of and protocol for the management of human bite injuries of the hand are presented. Early exploration of such wounds under local anesthesia improves the outcome by facilitating adequate cleansing of the wound and enabling deep structures to be visualized. In this way the risk of major sepsis and of the disability so frequently associated with these innocent-looking injuries can be reduced.     

Management of early human bites of the hand: a prospective randomized study

A prospective, randomized study was undertaken to determine if mechanical care of early human bites alone is sufficient therapy in the compliant patient or if prophylactic antibiotics (oral versus parenteral) are indicated. Beginning in June of 1985, patients presenting with human bites of the hand were entered into the study if (1) the bite was less than 24 hours old, (2) the patient was free of infection, (3) the bite did not penetrate the joint capsule, and (4) there was no injury to tendon. Forty-eight patients were ultimately segregated into one of three study groups after standardized ER mechanical wound care. Fifteen patients received an oral placebo, with 7 developing infection (46.7 percent). Sixteen patients received an oral antibiotic, and 17 patients received parenteral antibiotics. No infections were found in either of these latter groups. The results statistically substantiate that mechanical wound care alone is insufficient therapy. Oral antibiotics appear to be equal to intravenous antibiotics for prophylaxis. From a cost-benefit standpoint, vigorous cleaning, debridement, and coverage with a broad-spectrum oral antibiotic are adequate care for an uncomplicated bite in the compliant patient.     

Synoviocyte Derived-Extracellular Matrix Enhances Human Articular Chondrocyte Proliferation and Maintains Re-Differentiation Capacity at Both Low and Atmospheric Oxygen Tensions

BackgroundCurrent tissue engineering methods are insufficient for total joint resurfacing, and chondrocytes undergo de-differentiation when expanded on tissue culture plastic. De-differentiated chondrocytes show poor re-differentiation in culture, giving reduced glycosaminoglycan (GAG) and collagen matrix accumulation. To address this, porcine synoviocyte-derived extracellular matrix and low (5%) oxygen tension were assessed for their ability to enhance human articular chondrocyte expansion and maintain re-differentiation potential.MethodsPorcine synoviocyte matrices were devitalized using 3 non-detergent methods. These devitalized synoviocyte matrices were compared against tissue culture plastic for their ability to support human chondrocyte expansion. Expansion was further compared at both low (5%), and atmospheric (20%) oxygen tension on all surfaces. Expanded cells then underwent chondrogenic re-differentiation in aggregate culture at both low and atmospheric oxygen tension. Aggregates were assessed for their GAG and collagen content both biochemically and histologically.ResultsHuman chondrocytes expanded twice as fast on devitalized synoviocyte matrix vs. tissue culture plastic, and cells retained their re-differentiation capacity for twice the number of population doublings. There was no significant difference in growth rate between low and atmospheric oxygen tension. There was significantly less collagen type I, collagen type II, aggrecan and more MMP13 expression in cells expanded on synoviocyte matrix vs. tissue culture plastic. There were also significant effects due to oxygen tension on gene expression, wherein there was greater collagen type I, collagen type II, SOX9 and less MMP13 expression on tissue culture plastic compared to synoviocyte matrix. There was a significant increase in GAG, but not collagen, accumulation in chondrocyte aggregates re-differentiated at low oxygen tension over that achieved in atmospheric oxygen conditions.ConclusionsSynoviocyte-derived matrix supports enhanced expansion of human chondrocytes such that the chondrocytes are maintained in a state from which they can re-differentiate into a cartilage phenotype after significantly more population doublings. Also, low oxygen tension supports GAG, but not collagen, accumulation. These findings are a step towards the production of a more functional, tissue engineered cartilage.     

Prevention of tetanus in the wounded.

Recommendations for the prevention of tetanus in the wounded have been revised to incorporate the use of human tetanus immunoglobulin, which is now available in the United Kingdom. Surgical toilet is of prime importance for all wounds, and is usually sufficient for tetanus prophylaxis in patients with wounds that are less than six hours old, clean, non-penetrating, and with negligible tissue damage. Human tetanus immunoglobulin should be given to patients with more serious wounds sho have had toxoid injections over 10 years earlier, had an incomplete course, or do not know their immunity status. The importance of active immunization is emphasized. The recommendations should be regarded as guidelines as the circumstances in individual cases will differ.     

Major disaster planning.

In 1983 a coach crash brought a hospital''s major disaster plan into operation. The surgical aspects of the plan were assessed to see how well they matched up to three major aims: saving life, relieving pain and distress, and completing primary treatment of open wounds within eight hours of the accident. The last goal was not met for most of the 21 victims, mainly children with multiple deep dirty abrasions and extensive tissue loss. Having determined that none of the victims were in immediate danger the surgeons reassessed the priorities--in several cases disturbing dressings for a third or fourth time. The total time spent in theatre (in five theatres) was 37 hours, as opposed to the original estimated 10-15 hours. The experience gained in this accident suggests that a disaster plan should indicate the number of patients a single hospital can admit and that a senior surgeon should act as a coordinator and get surgeons working as soon as patients arrive, keeping two theatres reserved for lifesaving surgery. In this way primary treatment of wounds may be completed within eight hours of injury and the risk of infection reduced.     

An investigation of conventional microbial culture for the Naja atra bite wound,and the comparison between culture-based 16S Sanger sequencing and 16S metagenomics of the snake oropharyngeal bacterial microbiota

Naja atra is a major venomous snake found in Taiwan. The bite of this snake causes extensive wound necrosis or necrotizing soft tissue infection. Conventional microbial culture-based techniques may fail to identify potential human pathogens and render antibiotics ineffective in the management of wound infection. Therefore, we evaluated 16S Sanger sequencing and next-generation sequencing (NGS) to identify bacterial species in the oropharynx of N. atra. Using conventional microbial culture methods and the VITEK 2 system, we isolated nine species from snakebite wounds. On the basis of the 16S Sanger sequencing of bacterial clones from agar plates, we identified 18 bacterial species in the oropharynx of N. atra, including Morganella morganii, Proteus vulgaris, and Proteus mirabilis, which were also present in the infected bite wound. Using NGS of 16S metagenomics, we uncovered more than 286 bacterial species in the oropharynx of N. atra. In addition, the bacterial species identified using 16S Sanger sequencing accounted for only 2% of those identified through NGS of 16S metagenomics. The bacterial microbiota of the oropharynx of N. atra were modeled better using NGS of 16S metagenomics compared to microbial culture-based techniques. Stenotrophomonas maltophilia, Acinetobacter baumannii, and Proteus penneri were also identified in the NGS of 16S metagenomics. Understanding the bacterial microbiota that are native to the oropharynx of N. atra, in addition to the bite wound, may have additional therapeutic implications regarding empiric antibiotic selection for managing N. atra bites.     

Wolf or dog? Genetic identification of predators from saliva collected around bite wounds on prey

Wolf predation on livestock is a management problem in many areas and is often used to justify control measures against the wolves. However, wolves coexist with dogs across their range, and dogs could be responsible for attacks blamed on wolves. In this study we evaluate the possibility of obtaining sufficient DNA for species identification of the predator from saliva remaining close to bite wounds following a canid attack. Predator DNA of reasonably high quality was successfully extracted from bite wounds on two sheep that had been attacked on a farm and were genotyped using six informative microsatellite markers. A single consensus genotype could be constructed from the bite wounds of both sheep which we compared to genotypes obtained from Scandinavian wolves and dogs. The results clearly showed that the saliva sampled originated from a single dog. This report thus demonstrates the feasibility of predator species identification from bite wounds and also illustrates that it can not be taken for granted that wolves are responsible for canid livestock kills.     

Direction of Association between Bite Wounds and Mycobacterium bovis Infection in Badgers: Implications for Transmission

Background

Badgers are involved in the transmission to cattle of bovine tuberculosis (TB), a serious problem for the UK farming industry. Cross-sectional studies have shown an association between bite wounds and TB infection in badgers which may have implications for M. bovis transmission and control, although the sequence of these two events is unclear. Transmission during aggressive encounters could potentially reduce the effectiveness of policies which increase the average range of a badger and thus its opportunities for interaction with other social groups.

Methods

Data were obtained on badgers captured during a long term study at Woodchester Park, UK (1998–2006). Many badgers had multiple observations. At each observation, the badger was assigned a “state” depending on presence of bite wounds and/or TB infection. Hence each badger had a “transition” from the previous state to the current state. We calculated the numbers of each type of transition and the time spent in each state. Transition rates were calculated for each transition category, dividing the number of such transitions by the total time at risk. We compared the rate of bite wound acquisition in infected badgers with that for uninfected badgers and the rate of positive M.bovis test results in bitten badgers with that in unbitten badgers.

Results

The rate of bite wound acquisition in infected badgers (0.291 per year) was 2.09 (95% CI: 1.41, 3.08) times that in uninfected badgers (0.139 per year). The rate of positive M.bovis test results in bitten badgers (0.097 per year) was 2.45 (95% CI: 1.29, 4.65) times that in unbitten badgers (0.040 per year).

Conclusions

We found strong evidence of both potential sequences of events consistent with transmission via bite wounds and distinctive behaviour in infected badgers. The complex relationship between behaviour and infection must be considered when planning TB control strategies.     

The role of local fasciocutaneous flaps in total burn wound management.

The majority of acute burn wounds or delayed reconstructions are best managed simply with a skin graft. However, if vascularized tissue is mandatory, the local fasciocutaneous flap may have an important role in providing a single-stage technique for obtaining tissue nearly identical in color, texture, and consistency to that of the defect being restored. This review of 182 consecutive burn patients needing surgery found that they underwent 233 separate episodes for skin grafting. Appropriately, only a fraction of this number required some form of vascularized flap, with 14 patients having 21 local fasciocutaneous flaps. Six were elevated in previously skin-grafted regions, which is an advantage peculiar to this flap type. Three flaps (14 percent) suffered major complications requiring a second surgical intervention. Only six of all flaps were used for acute burn wounds, but two of the three complications accrued in this subset, with one directly attributable to wound infection. Since most flaps were required for either coverage or release of contractures about joints, it has been recommended that the initial surgical approach for treatment of the acute wound in these regions be altered to preserve the fascial plexus whenever possible to permit the use of this simple and expedient alternative if it is needed later.     

Operative management and outcome of complex wounds following total knee arthroplasty.

This study describes the treatment protocol for and the outcome of the management of complex wounds around total knee replacements. An analysis of 28 patients (29 knees) with complex defects who had surgery between January 1, 1986, and July 30, 1996, was performed. A specific management protocol was applied to each knee on the basis of the size and depth of the wound, the presence of infection, and the quality of soft tissue. Primary treatment included local wound care, debridement, and skin grafting or coverage with a fasciocutaneous flap, pedicled muscle flap, or free muscle transfer. Postoperatively, knees were evaluated using the Knee Society objective score. Successful salvage of the lower extremity was obtained in 28 knees (97 percent) and of the knee prosthesis in 24 of 29 knees (83 percent). Secondary plastic surgery procedures were necessary in five knees (17 percent), and secondary orthopedic procedures were necessary in four knees (14 percent). Successful salvage of total knee arthroplasty in the presence of a complex wound requires early identification of infection, aggressive irrigation and debridement, and early appropriate soft-tissue coverage. The use of our proposed algorithm will facilitate management of these complex wounds.     

Increasing frequency of bite wounds with increasing population density in Eurasian badgers, Meles meles

Eurasian badgers sometimes live in territorial, mixed-sex groups; the adaptive significance of this is not understood, but members generally interact amicably. None the less, badgers occasionally fight and inflict sometimes severe wounds on one another. Based on 498 badger life histories, from first emergence as a cub until death, documented during a 10-year trapping study at Wytham Woods, Oxfordshire, U.K., the patterns and rates of bite wounding and consequential scarring were examined. Male badgers received more wounds and more severe wounds than did females. Wounding rates for both sexes increased significantly with age, and there was evidence that heavier individuals received most wounds. No seasonal pattern in wounding rates was apparent. During the study, the badger population size increased three-fold and wounding rates, particularly in males, showed a density-dependent increase. The rate of bite wounding increased with group size, and this increase was more marked among males than among females. Among males, but not females, the rate of bite wounding also increased with the number of badgers living in adjoining territories.     

Dermal Bite Wounds as Indicators of Reproductive Seasonality and Behaviour in the Atlantic Stingray, Dasyatis sabina

Elasmobranch fishes exhibit a series of complex courtship and mating behaviours in which males inflict significant bite wounds to the body of female mates. However, the variety and frequency of mating wounds are not known across a full reproductive season for any species. We examined the distribution and abundance of dermal wounds in adult Atlantic stingrays, Dasyatis sabina, which have a protracted and defined mating season to determine (1) if dermal wounds can be used as indicators of mating activity, (2) whether different categories of bite wounds can be associated with specific mating behaviours, and (3) whether the skin thickness in females is sexually dimorphic. Adults of both sexes showed fresh wounds during the full duration of the mating season (October–June) and there was no relationship between ray size and wound density. Females had more total wounds than males in every month with a maximum average of 20.2 wounds per female in April. Mating wounds were categorized into five distinct forms: single track, double track, bite, margin abrasion and excision. Wounds were randomly distributed over the body of males but concentrated on the posterior half of the disc in females. Each wound type occurred in approximately equal proportions among sexes with the exception of the precopulatory and copulatory-induced margin abrasions which accounted for 13.7% of the total wounds in females but only 3.1% in males. We suggest that the pronounced and concurrent appearance of single track, double track and bite wounds among males results from random premating courtship attacks by males because females cannot be visually discriminated. However, the concentration of wounds on the posterior disc of females is consistent with the possible presence of olfactory cues (e.g. pheromones) that are released at the cloaca. The pectoral fin dermis of females was 50% thicker than that of males, which eliminated the excision of margins during male grasping and functions to reduce female injury. The temporal occurrence of wounds from October through June and peak in April is consistent with previous reproductive studies that show fresh sperm in the reproductive tract of females over the protracted mating period and also ovulation in late March or early April. The importance of social reproductive biting is discussed in relation to the reproductive induction hypothesis proposed to possibly explain the protracted mating of this species. Monitoring of dermal wounds provides a useful non-invasive technique to determine reproductive activity and a means for inference of social relationships in elasmobranch populations.