Don't Overlook Syphilis: An Atypical Rash in a Woman With Neurologic, Ocular, and Otic Involvement.

The manifestations of syphilis, a sexually transmitted infection caused by Treponema pallidum, can be divided into primary, secondary, or tertiary stages. In addition, syphilis can cause a latent infection with no clinical manifestations and be diagnosed solely by serologic testing. Secondary syphilis is especially known for causing a rash and diverse clinical manifestation which can make its diagnosis challenging-particularly in patients whose medical and sexual histories do not align with the classical epidemiologic and textbook description of secondary syphilis. We present a case of a 20-year-old immunocompetent heterosexual woman who presented with a rash atypical for secondary syphilis and accompanied by neurologic, ocular, and otic manifestations. This case highlights the importance of considering syphilis in the differential diagnosis of sexually active patients with a rash, even when their clinical presentations do not align with the textbook description of a syphilitic rash. Health care providers must remain vigilant for the diagnosis of syphilis in diverse clinical contexts, as early recognition and treatment are vital to prevent further syphilitic complications and transmission in military and civilian populations. Timely identification and intervention are crucial for both patient care and public health.

Prolonged Survival Following Intra-abdominal Mycobacterium abscessus Infection Without Antimicrobial Therapy or Surgical Intervention.

Management of Mycobacterium abscessus infection involves prolonged multidrug antibiotic therapy with surgical resection indicated in extensive disease and abscesses. We report a case of post-surgical intra-abdominal M. abscessus infection with prolonged survival and radiographic resolution without intervention. A 51-year-old female who had a prolonged hospital stay with multiple surgeries following a complicated laparoscopic sleeve gastrectomy developed multiple M. abscessus intra-abdominal and abdominal wall abscesses with cutaneous fistulae. She was started on a multidrug antibiotic regimen. However, the patient terminated the regimen after 4 weeks due to intolerable side effects and was transitioned to hospice care. She showed steady clinical improvement with radiographic resolution of the abscesses over the next year. In the context of the limited understanding of these infections, our finding is notable, given that in this period, she avoided potential hospitalizations, life altering side effects of prolonged antimicrobial therapy, and complications from more surgeries.

Interrater agreement of the HEART score history component: A chart review study.

Study objectives: This study investigated the interrater reliability of the history component of the HEART (history, electrocardiogram, age, risk, troponin) score between physicians in emergency medicine (EM) and internal medicine (IM) at 1 tertiary-care center. Methods: We conducted a retrospective, secondary analysis of 60 encounters selected randomly from a database of 417 patients with chest pain presenting from January to June 2016 to an urban tertiary-care center. A total of 4 raters (1 EM attending, 1 EM resident, 1 IM attending, and 1 IM resident) scored the previously abstracted history data from these encounters.The primary outcome was the interrater agreement of HEART score history components, as measured by kappa coefficient, between EM and IM attending physicians. Secondary outcomes included the agreement between attending and resident physicians, overall agreement, pairwise percent agreement, and differences in scores assigned. Results: The kappa value for the EM attending physician and IM attending physician was 0.33 with 55% agreement. Interrater agreement of the other pairs was substantial between EM attending and resident but was otherwise fair to moderate. Percent agreement between the other pairs ranged from 48.3% to 80%. There was a significant difference in scores assigned and the subgroup in which there was disagreement between the raters demonstrated significantly higher scores by the EM attending and resident when compared to the IM attending. Conclusion: This study demonstrates fair agreement between EM and IM attending physicians in the history component of the HEART score with significantly higher scores by the EM attending physician in cases of disagreement at 1 tertiary-care center.

Pan-drug resistant Providencia rettgeri contributing to a fatal case of COVID-19.

Following prolonged hospitalization that included broad-spectrum antibiotic exposure, a strain of Providencia rettgeri was cultured from the blood of a patient undergoing extracorporeal membrane oxygenation treatment for hypoxic respiratory failure due to COVID-19. The strain was resistant to all antimicrobials tested including the novel siderophore cephalosporin, cefiderocol. Whole genome sequencing detected ten antimicrobial resistance genes, including the metallo-ß-lactamase bla NDM-1, the extended-spectrum ß-lactamase bla PER-1, and the rare 16S methyltransferase rmtB2.

Proton Pump Inhibitor-Induced Hypomagnesemia: A Rare, Potentially Fatal Complication.

Hypomagnesemia has been associated with a variety of abnormalities, including neurological, cardiac and secondary electrolyte abnormalities. We present the case of a 77-year-old male who presented to the emergency department with tremor and difficulty walking and was found to have severe hypomagnesemia necessitating hospital admission. After thorough workup, the patient's hospital course concluded that the profound hypomagnesemia was secondary to proton pump inhibitor use. Physicians should be aware of proton pump inhibitor-induced hypomagnesemia as a rare, but easily correctable etiology of hypomagnesemia.

The use of desiccation to treat Staphylococcus aureus biofilm-infected wounds.

Chronic wounds colonized with biofilm present a major burden to our healthcare system. While the current paradigm for wound healing is to maintain a moist environment, we sought to evaluate the effects of desiccation, and the ability of honey to desiccate wounds, on wound healing characteristics in Staphylococcus aureus biofilm wounds. In vivo biofilm wound healing after exposure to open-air desiccation, honey, molasses, and saline was analyzed using a rabbit ear model of S. aureus biofilm wounds previously developed by our group. Wound morphology was examined using scanning electron microscopy and granulation tissue deposition was measured using light microscopy with hematoxylin and eosin staining. Viable bacterial counts in rabbit ear biofilm wounds and scabs were measured using a drop dilution method. In vitro S. aureus growth curves were established using tryptic soy broth containing honey and glycerol. Gene expression analysis of rabbit ear wounds was performed using reverse transcription quantitative PCR. Rabbit ear S. aureus biofilm wounds exposed to open-air desiccation, honey, and molasses developed a dry scab, which displaced the majority of biofilm bacteria off of the wound bed. Wounds treated with open-air desiccation, honey, and molasses expressed lower levels of the inflammatory markers tumor necrosis factor-α and interleukin-1ß at postoperative day 12 compared with wounds treated with saline, and had increased levels of granulation tissue formation. In vitro growth of S. aureus in tryptic soy broth was inhibited by the presence of honey to a greater extent than by the presence of osmolality-matched glycerol. Desiccation of chronic wounds colonized with biofilm via exposure to open air or honey leads to improved wound healing by decreasing bacterial burden and inflammation, and increasing granulation tissue formation. The ability of honey to help heal chronic wounds is at least in part due to its ability to desiccate bacterial biofilm, but other factors clearly contribute.

Dermal wound transcriptomic responses to Infection with Pseudomonas aeruginosa versus Klebsiella pneumoniae in a rabbit ear wound model.

BACKGROUND: Bacterial infections of wounds impair healing and worsen scarring. We hypothesized that transcriptome analysis of wounds infected with Klebsiella pneumoniae (K.p.) or Pseudomonas aeruginosa (P.a.) would indicate host-responses associated with the worse healing of P.a.- than K.p.-infected wounds. METHODS: Wounds created on post-operative day (POD) 0 were infected during the inflammatory phase of healing on POD3 and were harvested on POD4 for microarray and transcriptome analysis. Other wounds received topical antibiotic after infection for 24 hours to promote biofilm development, and were harvested on POD6 or POD12. RESULTS: Wounds infected for 24 hours, relative to uninfected wounds, elevated transcripts of immune-response functions characteristic of infiltrating leukocytes. But P.a.-infected wounds elevated many more transcripts and to higher levels than K.p.-infected wounds. Coincidently, suppressed transcripts of both wounds enriched into stress-response pathways, including EIF2 signaling; however, this was more extensive for P.a.-infected wounds, including many-fold more transcripts enriching in the 'cell death' annotation, suggesting resident cutaneous cell toxicity in response to a more damaging P.a. inflammatory milieu. The POD6 wounds were colonized with biofilm but expressed magnitudes fewer immune-response transcripts with no stress-response enrichments. However, elevated transcripts of P.a.-infected wounds were inferred to be regulated by type I interferons, similar to a network unique to P.a.-infected wounds on POD4. On POD12, transcripts that were more elevated in K.p.-infected wounds suggested healing, while transcripts more elevated in P.a.-infected wounds indicated inflammation. CONCLUSIONS: An extensive inflammatory response of wounds was evident from upregulated transcripts 24 hours after infection with either bacterium, but the response was more intense for P.a.- than K.p.-infected wounds. Coincidently, more extensive down-regulated transcripts of P.a.-infected wounds indicated a stronger "integrated stress response" to the inflammatory milieu that tipped more toward cutaneous cell death. Unique to P.a.-infected wounds on POD4 and POD6 were networks inferred to be regulated by interferons, which may result from intracellular replication of P.a. These data point to specific downregulated transcripts of cells resident to the wound as well as upregulated transcripts characteristic of infiltrating leukocytes that could be useful markers of poorly healing wounds and indicators of wound-specific treatments for improving outcomes.

Deficient cytokine expression and neutrophil oxidative burst contribute to impaired cutaneous wound healing in diabetic, biofilm-containing chronic wounds.

Diabetic patients exhibit dysregulated inflammatory and immune responses that predispose them to chronic wound infections and the threat of limb loss. The molecular underpinnings responsible for this have not been well elucidated, particularly in the setting of wound biofilms. This study evaluates host responses in biofilm-impaired wounds using the TallyHo mouse, a clinically relevant polygenic model of type 2 diabetes. No differences in cytokine or Toll-like receptor (TLR) expression were noted in unwounded skin or noninoculated wounds of diabetic and wild-type mice. However, diabetic biofilm-containing wounds had significantly less TLR 2, TLR 4, interleukin-1ß, and tumor necrosis factor-α expression than wild-type wounds with biofilm (all p < 0.001). Both groups had similar bacterial burden and neutrophil infiltration after development of biofilms at 3 days postwounding, but diabetic wounds had significantly less neutrophil oxidative burst activity. This translated into a log-fold greater bacterial burden and significant delay of wound epithelization for biofilm-impaired diabetic wounds at 10 days postwounding. These results suggest that impaired recognition of bacterial infection via the TLR pathway leading to inadequate cytokine stimulation of antimicrobial host responses may represent a potential mechanism underlying diabetic susceptibility to wound infection and ulceration.

Noncontact, low-frequency ultrasound as an effective therapy against Pseudomonas aeruginosa-infected biofilm wounds.

Bacterial biofilms, a critical chronic wound mediator, remain difficult to treat. Energy-based devices may potentially improve healing, but with no evidence of efficacy against biofilms. This study evaluates noncontact, low-frequency ultrasound (NLFU) in the treatment of biofilm-infected wounds. Six-millimeter dermal punch wounds in rabbit ears were inoculated with 10(7) colony-forming units of Pseudomonas aeruginosa or left as sterile controls. A biofilm was established in vivo using our published model. NLFU treatment was carried out every other day or every day, with contralateral ear wounds acting as internal, untreated controls. Wounds were harvested for several quantitative endpoints and scanning electron microscopy to evaluate the biofilm structure. The P. aeruginosa biofilm consistently impaired wound epithelialization and granulation. NLFU, both every other day and every day, improved healing and reduced bacterial counts relative to untreated controls (p < 0.05). Scanning electron microscopy confirmed a qualitative decrease in bacteria after both treatments. NLFU also reduced inflammatory cytokine expression (p < 0.05). Our study suggests that NLFU is an effective therapy against P. aeruginosa wound biofilm. This represents the first in vivo evidence of energy-based modalities' impact on wound biofilm, setting the foundation for future mechanistic studies. Continued wound care technology research is essential to improving our understanding, and treatment, of biofilm-infected chronic wounds.

Bacteriophage therapy for Staphylococcus aureus biofilm-infected wounds: a new approach to chronic wound care.

BACKGROUND: Bacterial biofilms, which are critical mediators of chronic wounds, remain difficult to treat with traditional methods. Bacteriophage therapy against biofilm has not been rigorously studied in vivo. The authors evaluate the efficacy of a species-specific bacteriophage against Staphylococcus aureus biofilm-infected wounds using a validated, quantitative, rabbit ear model. METHODS: Six-millimeter dermal punch wounds in New Zealand rabbit ears were inoculated with wild-type or mutant, biofilm-deficient S. aureus. In vivo biofilm was established and maintained using procedures from our previously published wound biofilm model. Wounds were left untreated, or treated every other day with topical S. aureus-specific bacteriophage, sharp débridement, or both. Histologic wound healing and viable bacterial count measurements, and scanning electron microscopy were performed following harvest. RESULTS: Wild-type S. aureus biofilm wounds demonstrated no differences in healing or viable bacteria following bacteriophage application or sharp débridement alone. However, the combination of both treatments significantly improved all measured wound healing parameters (p < 0.05) and reduced bacteria counts (p = 0.03), which was confirmed by scanning electron microscopy. Bacteriophage treatment of biofilm-deficient S. aureus mutant wounds alone also resulted in similar trends for both endpoints (p < 0.05). CONCLUSIONS: Bacteriophages can be an effective topical therapy against S. aureus biofilm-infected wounds in the setting of a deficient (mutant) or disrupted (débridement) biofilm structure. Combination treatment aimed at disturbing the extracellular biofilm matrix, allowing for increased penetration of species-specific bacteriophages, represents a new and potentially effective approach to chronic wound care. These results establish principles for biofilm therapy that may be applied to several different clinical and surgical problems.

Comparative analysis of single-species and polybacterial wound biofilms using a quantitative, in vivo, rabbit ear model.

INTRODUCTION: The recent literature suggests that chronic wound biofilms often consist of multiple bacterial species. However, without appropriate in vivo, polybacterial biofilm models, our understanding of these complex infections remains limited. We evaluate and compare the effect of single- and mixed-species biofilm infections on host wound healing dynamics using a quantitative, in vivo, rabbit ear model. METHODS: Six-mm dermal punch wounds in New Zealand rabbit ears were inoculated with Staphylococcus aureus strain UAMS-1, Pseudomonas aeruginosa strain PAO1, or both, totaling 10/6 colony-forming units/wound. Bacterial proliferation and maintenance in vivo were done using procedures from our previously published model. Wounds were harvested for histological measurement of wound healing, viable bacterial counts using selective media, or inflammatory cytokine (IL-1ß, TNF-α) expression via quantitative reverse-transcription PCR. Biofilm structure was studied using scanning electron microscopy (SEM). For comparison, biofilm deficient mutant UAMS-929 replaced strain UAMS-1 in some mixed-species infections. RESULTS: Bacterial counts verified the presence of both strains UAMS-1 and PAO1 in polybacterial wounds. Over time, strain PAO1 became predominant (p<0.001). SEM showed colocalization of both species within an extracellular matrix at multiple time-points. Compared to each monospecies infection, polybacterial biofilms impaired all wound healing parameters (p<0.01), and increased expression of IL-1ß and TNF-α (p<0.05). In contrast, mixed-species infections using biofilm-deficient mutant UAMS-929 instead of wild-type strain UAMS-1 showed less wound impairment (p<0.01) with decreased host cytokine expression (p<0.01), despite a bacterial burden and distribution comparable to that of mixed-wild-type wounds. CONCLUSIONS: This study reveals that mixed-species biofilms have a greater impact on wound healing dynamics than their monospecies counterparts. The increased virulence of polybacterial biofilm appears dependent on the combined pathogenicity of each species, verified using a mutant strain. These data suggest that individual bacterial species can interact synergistically within a single biofilm structure.

In vivo modeling of biofilm-infected wounds: a review.

Chronic wounds continue to represent a difficult and complex problem for both patients and healthcare providers. Bacterial biofilms represent a critical component of nonhealing wounds, utilizing several different mechanisms to inhibit innate inflammatory pathways and resist traditional therapeutics. Although in vitro biofilm systems have been well described and studied, understanding the intricacies of wound biofilm pathology requires appropriate in vivo models to understand the interactions between bacteria and host. In an effort to clarify the available literature, this review describes and critically evaluates all of the in vivo wound biofilm models currently published to-date, including model advantages and clinical applicability. We will also address the need for continued therapeutic development and testing using these currently available in vivo models.

Quantitative comparison and analysis of species-specific wound biofilm virulence using an in vivo, rabbit-ear model.

BACKGROUND: Although bacterial biofilm is recognized as an important contributor to chronic wound pathogenesis, differences in biofilm virulence between species have never been studied in vivo. STUDY DESIGN: Dermal punch wounds in New Zealand white rabbit ears were inoculated with Klebsiella pneumoniae, Staphylococcus aureus, or Pseudomonas aeruginosa, or left uninfected as controls. In vivo biofilm was established and maintained using procedures from our previously published wound biofilm model. Virulence was assessed by measurement of histologic wound healing and host inflammatory mediators. Scanning electron microscopy (SEM) and bacterial counts verified biofilm viability. Extracellular polymeric substance (EPS)-deficient P aeruginosa was used for comparison. RESULTS: SEM confirmed the presence of wound biofilm for each species. P aeruginosa biofilm-infected wounds showed significantly more healing impairment than uninfected, K pneumoniae, and S aureus (p < 0.05), while also triggering the largest host inflammatory response (p < 0.05). Extracellular polymeric substance-deficient P aeruginosa demonstrated a reduced impact on the same quantitative endpoints relative to its wild-type strain (p < 0.05). CONCLUSIONS: Our novel analysis demonstrates that individual bacterial species possess distinct levels of biofilm virulence. Biofilm EPS may represent an integral part of their distinct pathogenicity. Rigorous examination of species-dependent differences in biofilm virulence is critical to developing specific therapeutics, while lending insight to the interactions within clinically relevant, polybacterial biofilms.

Equivalent effects of topically-delivered adipose-derived stem cells and dermal fibroblasts in the ischemic rabbit ear model for chronic wounds.

BACKGROUND: Mesenchymal stem cells (MSC) have garnered considerable attention in plastic surgery. Via proliferation/differentiation or the elaboration of paracrine factors, MSC and their adipose-derived stem cell counterparts (ADSC) have been suggested to stimulate cutaneous wound healing. Previous reports have been limited by a lack of appropriate controls and the lack of a clinically-relevant context or ability to extrapolate to human wound healing. OBJECTIVES: The authors qualitatively and quantitatively evaluate the ability of ADSC to improve wound healing in an ischemic variant of their well-established rabbit ear wound model. METHODS: To incorporate ischemia, a major pathophysiologic factor in human chronic wounds, into our model, two of the three main arteries to the rabbit ear were ligated before wounding. Green fluorescent protein (GFP)-labeled ADSC or rabbit dermal fibroblasts (RDF) were then applied to wounds and histologic parameters of healing quantified. RESULTS: At Postoperative Day (POD) 1, both cell types were present in a uniform distribution across wounds and positive for the proliferation marker Ki-67. By POD 7 and continuing through POD 10, ADSC and RDF contributed similarly to the accumulation of stratified "neogranulation" across the wound bed. No statistically-significant differences were observed between ADSC and RDF in terms of this positive effect on granulation (P=.2-.3 for comparison of mean granulation tissue gaps and areas). CONCLUSIONS: ADSC and RDF can be delivered topically to wounds, resulting in a high level of engraftment in the ischemic background. Cellular wound therapy holds promise for chronic wound healing as well as other antiscarring therapies, but further studies are warranted before full clinical translation.

Understanding the host inflammatory response to wound infection: an in vivo study of Klebsiella pneumoniae in a rabbit ear wound model.

Wound infection development is critically dependent on the complex interactions between bacteria and host. Klebsiella pneumoniae has become an increasingly common wound pathogen, but its natural history within wounds has never been studied. Using a validated, in vivo rabbit ear model, wounds were inoculated with K. pneumoniae at different concentrations (10²-107 colony-forming units) with measurement of viable and nonviable bacterial counts, histological wound-healing parameters, and host inflammatory gene expression at multiple time points postinoculation (48, 96, and 240 hours). Bacteria and wound morphologies were evaluated with scanning electron microscopy. Comparable experiments were performed in ischemic ears to model immune response impairment. All wounds, despite different inoculants, equilibrated to similar bacterial concentrations by 96 hours. With a 106 colony-forming units inoculant, wounds at 240 hours showed decreased bacterial counts (p < 0.01), with a corresponding improvement in healing (p < 0.01) and a decrease in inflammatory response (p < 0.05). In contrast, ischemic wounds revealed impaired inflammatory gene expression (p < 0.05) resulting in higher steady-state bacterial concentrations (p < 0.01), impaired healing (p < 0.05), and biofilm formation on scanning electron microscopy. We conclude that a normal inflammatory response can effectively stabilize and overcome a K. pneumoniae wound infection. An impaired host cannot control this bacterial burden, preventing adequate healing while allowing bacteria to establish a chronic presence. Our novel study quantitatively validates the host immune response as integral to wound infection dynamics.

Treatment of Pseudomonas aeruginosa biofilm-infected wounds with clinical wound care strategies: a quantitative study using an in vivo rabbit ear model.

BACKGROUND: Bacterial biofilm is recognized as a major detriment to wound healing. The efficacy of traditional wound care against biofilm has never been studied. The authors evaluated the effect of clinical strategies against biofilm-infected wounds in a quantitative, in vivo model. METHODS: Using a rabbit ear biofilm model, wounds were inoculated with Pseudomonas aeruginosa or left as uninfected controls. Inoculated wounds acted as untreated controls or underwent treatment: every-other-day sharp débridement (I), lavage (II), Silvadene (III), or lavage and Silvadene (IV), or initial débridement with daily lavage and Silvadene (V). Wounds were harvested on days 12 and 18. Histological wound healing parameters and viable bacterial counts were measured. Biofilm structure was studied with scanning electron microscopy. RESULTS: Uninfected controls healed better than P. aeruginosa biofilm-infected wounds across all parameters (p = 0.01). Groups IV and V demonstrated improved healing (p = 0.05) and decreased bacterial count (p = 0.05) compared with untreated P. aeruginosa biofilm, whereas groups I through III showed no differences in either. Scanning electron microscopy following a group V treatment showed temporary disruption of biofilm structure, which reformed in 24 hours. CONCLUSIONS: Pseudomonal biofilm markedly impairs wound healing, shown quantitatively using our in vivo model. Despite common practice, wound care strategies cannot restore biofilm wounds to a healing phenotype when used alone or infrequently. The durability of biofilm extends nonhealing wound chronicity, thus requiring aggressive, multimodal therapy aimed at reducing bacterial burden. The authors' novel, rigorous study validates critical principles applicable to all clinical wound care.

The TallyHo polygenic mouse model of diabetes: implications in wound healing.

BACKGROUND: Impairments in wound healing represent a significant source of morbidity and mortality in patients with diabetes. To help uncover the derangements associated with diabetic wound healing, murine animal models have been extensively used. In this article, the authors present results, and the accompanying wound healing implications, from experiments across three validated wound healing models using a newer polygenic strain of diabetes. METHODS: The authors investigated the wound healing impairments of the TallyHo/JnJ diabetic mouse strain, using three validated wound healing models: an incisional model, a splinted excisional model, and a cutaneous ischemia-reperfusion injury model. Appropriate control strain mice were used for comparison. Wounds were analyzed using gross, histologic, and molecular techniques. RESULTS: TallyHo mice displayed deficits across all three wound healing models. There was a reduced resistance/response to oxidative stress and a global decrease in the initial inflammatory response to healing. In addition, there was a global decrease in the stimulus for angiogenesis and collagen formation, ultimately leading to reduced reepithelialization, granulation tissue formation, wound contraction, and wound tensile strength. Gross and histologic findings were corroborated with molecular data, which revealed a significant down-regulation of important cytokines, including vascular endothelial growth factor, neutrophilic attractant protein-2, monocyte chemoattractant protien-1, heme oxygenase-1, interleukin-1ß, and interleukin-6, when normalized to the control strain (p<0.05). CONCLUSIONS: The TallyHo polygenic mouse model of diabetes demonstrates predictable and clinically relevant wound healing impairments that offer important implications into the derangements of diabetic wound healing observed clinically. Therapeutics targeting these specific derangements could provide improvements in the care of diabetic wounds.

Development of a novel, highly quantitative in vivo model for the study of biofilm-impaired cutaneous wound healing.

A growing body of evidence suggests that in addition to hypoxia, ischemia-reperfusion injury, and intrinsic host factors, bacterial biofilms represent a fourth major pillar in chronic wound pathogenesis. Given that most studies to date rely on in vitro or observational clinical data, our aim was to develop a novel, quantitative animal model enabling further investigation of the biofilm hypothesis in vivo. Dermal punch wounds were created in New Zealand rabbit ears, and used as uninfected controls, or inoculated with green fluorescent protein-labeled Staphylococcus aureus to form wounds with bacteria predominantly in the planktonic or biofilm phase. Epifluorescence and scanning electron microscopy revealed that S. aureus rapidly forms mature biofilm in wounds within 24 hours of inoculation, with persistence of biofilm viability over time seen through serial bacterial count measurement and laser scanning confocal imaging at different time points postwounding and inoculation. Inflammatory markers confirmed that the biofilm phenotype creates a characteristic, sustained, low-grade inflammatory response, and that over time biofilm impairs epithelial migration and granulation tissue in-growth, as shown histologically. We have established and validated a highly quantitative, reproducible in vivo biofilm model, while providing evidence that the biofilm phenotype specifically contributes to profound cutaneous wound healing impairment. Our model highlights the importance of bacterial biofilms in chronic wound pathogenesis, providing an in vivo platform for further inquiry into the basic biology of bacterial biofilm-host interaction and high-throughput testing of antibiofilm therapeutics.