Effectiveness of SCAR-Q for assessment of incisional SCAR after implant-based reconstruction in breast cancer patients: Can it be a tool for incision selection?

Incisional scarring is a factor of cosmetic appearance evaluated after breast reconstruction, along with the shape, position, and size of the breast. This study aimed to examine the effect of the incision scar location on patient satisfaction after breast reconstruction. Using the Japanese version of the SCAR-Q, we assessed the scar appearance, symptoms and psychosocial effects. Plastic surgeons performed assessments using the Manchester Scar Scale. The patients were divided into two groups: those with scars on the margins of the breast (MB group) and those with scars in the breast area (IB group). The results revealed that patients in the MB group reported significantly higher satisfaction with the scar appearance and psychological impact than those in the IB group. However, assessments using the Manchester Scar Scale did not reveal any significant differences between the two groups. In conclusion, this study underscores the importance of patient-reported outcomes in the evaluation of scar satisfaction after breast reconstruction. Patients tend to prefer and have higher satisfaction with scars along the breast margin, which offers valuable insights into surgical decisions. Further studies with larger and more diverse sample sizes are required for validation.

Deep palm burn treated with enzymatic debridement followed by autologous skin cell suspension: a case study.

Despite improvements in treatment methods and outcomes, burns remain one of the principal causes of mortality and morbidity worldwide. Burns involving the hands are estimated to occur in >80% of people with burns. Hand burns have also been associated with long-term social, psychological and physical consequences that can impede a patient's full reintegration to the community and decrease their overall quality of life. Clinically, when the trajectory towards complete re-epithelialisation stalls in deep burn wounds of the hand, skin grafting is indicated, but cosmetic problems often remain. A recent publication highlighted common complications for burns involving the hand such as scar disturbances (26%) and scar contractures (14%). Innovative approaches with the potential to reduce the occurrence of complicating scar disturbances and contractures are sought by healthcare providers specialising in burns. This case report describes a novel approach to wound closure using a topical concentrate of proteolytic enzymes followed by the application of an autologous skin cell suspension. This combination was effective in achieving early and complete re-epithelialisation of a deep burn of the palm of a 28-year-old male patient, while potentially affording a favourable impact on hypertrophic scarring or scar contracture.

Surgical treatment of tracheocutaneous fistula and tracheostomy scars using a hinged flap and local myocutaneous flap.

Tracheocutaneous fistula and tracheostomy scar are complications associated with the prolonged use of tracheostomy tubes. They have functional and cosmetic problems owing to tracheal tugging during swallowing and easily visible scars. Although many procedures exist to correct this issue, there is no consensus on the optimal surgical technique. Therefore, an ideal surgical procedure was devised. The study was performed on 12 patients between September 2016 and May 2021. All patients had persistent tracheocutaneous fistulas or hypertrophic scars on the neck after tracheostomy. All procedures were performed using a hinged flap and two myocutaneous local flaps. All patients had no complications, and their aesthetics were excellent in postoperative photographs. The scar was better on the straight scar when the flap's skin is denuded than on the VY advancement flap. It should be noted, however, that this procedure can cause the flap to become congested in a short period after head and neck surgery. This procedure is safe, reliable and simple for surgical closure. This was found to produce excellent cosmetic results with no major complications.

Volume Prediction of Extended Latissimus Dorsi Musculocutaneous Flap for Breast Reconstruction Using a Computed Tomography Volume-Rendering Technique with an X-ray Contrast Thread Marking.

BACKGROUND: The extended latissimus dorsi (ELD) musculocutaneous flap is one of the surgical techniques used for breast reconstruction. Preoperative preparation to determine the exact amount of flap tissue to be harvested is important to achieve a good outcome with autologous tissue reconstruction. However, few reports exist on objective preoperative volume prediction of ELD flaps. The purpose of this study was to quantify the elevated ELD volume as a preoperative plan. METHODS: Patients who underwent immediate or delayed breast reconstruction with ELD flap after mastectomy between March 2015 and January 2022 are included. (1) The ELD flap was designed preoperatively, X-ray contrast thread was applied along the design, and CT imaging was performed in the same lateral supine position as the surgical position. 3D images were constructed, and the volume-rendering method was used to obtain the integrated volume. (2) Intraoperative ELD flap volume was calculated using the water displacement method. The correlation between (1) and (2) was examined. RESULTS: (1) The mean preoperative predicted value was 290.2 mL and (2) the mean intraoperative ELD flap volume was 298.3 mL. The correlation coefficient between the two volumes was 0.93, indicating that they were correlated. CONCLUSION: We could quantify the ELD flap volume using the volume-rendering method with X-ray contrast threads. This study could be a useful method for preoperative prediction planning of the ELD flap in breast reconstruction. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Surgical Techniques to Prevent Nipple-Areola Complex Malposition in Two-Stage Implant-Based Breast Reconstruction.

Background Appropriate position of the nipple-areolar complex (NAC) is crucial following nipple-sparing mastectomy (NSM). The prevention of NAC malposition in two-stage implant-based breast reconstruction has not been well described, and the efficacy of the techniques has not been evaluated. This study aimed to evaluate the efficacy of our technique to prevent NAC malposition in patients who underwent implant-based breast reconstruction after NSM. Methods Patients who underwent two-stage implant-based breast reconstruction with NSM between January 2012 and December 2019 were included. We used a surgical technique to fix the NAC to the rigid base, assuming a pocket-like appearance, with pectoralis major muscle and lateral adipofascial flap at the time of tissue expander (TE) insertion. Patients were classified into two groups based on the performance of the technique for the prevention of NAC malposition. Results In 35 patients who underwent implant-based breast reconstruction after NSM, the clavicle-to-nipple distance ratio was 96.0 ± 5.0% in those who underwent NAC fixation and 86.1 ± 11.5% in those who did not undergo NAC fixation. Conclusions Using our technique, NAC malposition could be prevented in two-stage implant-based breast reconstruction. NAC fixation during TE insertion was found to be extremely effective. This procedure successfully prevented NAC malposition without the formation of extra scars.

Beneficial effects of transdermal administration of tamoxifen on capsular contracture after breast implantation in murine models.

BACKGROUND AND AIM: Capsular contracture is the most common complication with smooth-type silicone implants. We investigated the preventive effect of an active metabolite of tamoxifen, 4-hydroxytamoxifen (4-OH TAM), on capsular contracture. METHODS: A silicone sheet was implanted into the back of 28 female ICR mice. Mixtures of gel with 0.2% 4-OH TAM and 0.1% 4-OH TAM were administered transdermally once a day for 4 weeks. Saline was administered to the control. After killing the mice, capsular thickness was measured in H&E-stained specimens. Estrogen receptor (ER), α-smooth muscle actin (α-SMA), and transforming growth factor-ß (TGF-ß) expressions were immunohistochemically investigated in the capsules. RESULTS: The capsule was thinner in the 0.2% 4-OH TAM gel group than in the control group (control, 0.1% 4-OH TAM gel, 0.2% 4-OH TAM gel: 52.8 ± 3.4 µm, 54.2 ± 6.8 µm, 46.4 ± 3.3 µm, respectively). ER was found in most fibroblasts of all samples. α-SMA expression in the capsule was significantly lower in the 4-OH TAM gel groups than in the control group (control = 70.0 ± 3.4%, 0.1% 4-OH TAM = 57.0 ± 3.4%, 0.2% 4-OH TAM = 49.4 ± 4.9%). TGF-ß expression was significantly reduced by the 4-OH TAM gel injections dose-dependently (control = 67.3 ± 2.2%, 0.1% 4-OH TAM = 52.4 ± 3.1%, 0.2% 4-OH TAM = 45.1 ± 2.4%). CONCLUSIONS: The transdermal administration of 0.1% and 0.2% 4-OH TAM gels inhibited capsule development. The inhibition of TGF-ß expression is a mechanism by which 4-OH TAM suppresses fibroblast growth, preventing capsular formation.

Adding collagen to adipose tissue transplant increases engraftment by promoting cell proliferation, neovascularisation and macrophage activity in a rat model.

To clarify the effect of collagen addition to transplanted adipose tissue on angiogenesis, cell proliferation and tissue remodelling process and reveal whether collagen addition contributes to improving transplanted adipose tissue engraftment in rats. Adipose tissue was harvested from the inguinal and injected into the back of the rat, in addition to collagen. Engraftment tissue was harvested, semi-quantitatively evaluated and underwent haematoxylin and eosin or Perilipin staining. Moreover, we evaluated viable adipocyte counts and neovascularisation. Macrophages were evaluated using flow cytometry, and the adiponectin or vascular endothelial growth factor (VEGF) mRNA was detected using real-time polymerase chain reaction. By collagen addition to transplanted adipose tissue, higher engraftment rate semi-quantitatively and a greater number of new blood vessels histologically were identified. Perilipin staining revealed a higher adipocyte number. The total cell, M1 macrophage and M2 macrophage count were higher. There was increased adiponectin mRNA significantly at week 4 compared to that at week 1 after transplantation. Note that the expression levels of VEGF mRNA increased. In rats, adding collagen enhanced cell proliferation, induced M2 macrophages, which are involved in wound healing, and promoted adipocytes and neovascularisation. Therefore, collagen addition to transplanted adipose tissue could increase the engraftment rate of adipose tissue.

Negative-pressure wound therapy for donor-site closure in radial forearm free flap: A systematic review and meta-analysis.

Negative-pressure wound therapy (NPWT) is often used for skin graft site dressing, and several studies have reported that its use improves skin graft failure in the forearm flap donor site. The present systematic review aimed to evaluate the efficacy of NPWT with skin graft for donor-site closure in radial forearm free flap (RFFF) reconstruction. A systematic search in PubMed, Web of Science, and Cochrane Library databases was conducted. The search terms used for PubMed were ([radial forearm]) AND ([donor]) AND ([negative pressure or vacuum]). This review was registered in the International Prospective Register of Systematic Reviews and performed in accordance with the preferred reporting items for systematic reviews and meta-analyses statement. Three prospective randomised controlled trials and three retrospective comparative studies were included. Compared with conventional bolster dressing, the use of NPWT dressing did not lead to significant improvements in partial skin graft loss, tendon exposure, and other complications. NPWT improved hand functionality earlier; nonetheless, the cost of the device and dressings was a disadvantage. The use of NPWT for skin graft fixation in the RFFF donor site is not generally recommended.

Postoperative malignant hyperthermia confirmed by calcium-induced calcium release rate after breast cancer surgery, in which prompt recognition and immediate dantrolene administration were life-saving: a case report.

BACKGROUND: Malignant hyperthermia (MH) is a rare genetic disease characterized by the development of very serious symptoms, and hence prompt and appropriate treatment is required. However, postoperative MH is very rare, representing only 1.9% of cases as reported in the North American Malignant Hyperthermia Registry (NAMHR). We report a rare case of a patient who developed sudden postoperative hyperthermia after mastectomy, which was definitively diagnosed as MH by the calcium-induced calcium release rate (CICR) measurement test. CASE PRESENTATION: A 61-year-old Japanese woman with a history of stroke was hospitalized for breast cancer surgery. General anesthesia was introduced by propofol, remifentanil, and rocuronium. After intubation, anesthesia was maintained using propofol and remifentanil, and mastectomy and muscle flap reconstruction surgery was performed and completed without any major problems. After confirming her spontaneous breathing, sugammadex was administered and she was extubated. Thereafter, systemic shivering and masseter spasm appeared, and a rapid increase in body temperature (maximum: 38.9 °C) and end-tidal carbon dioxide (ETCO2) (maximum: 59 mmHg) was noted. We suspected MH and started cooling the body surface of the axilla, cervix, and body trunk, and administered chilled potassium-free fluid and dantrolene. After her body temperature dropped and her shivering improved, dantrolene administration was ended, and finally she was taken to the intensive care unit (ICU). Body cooling was continued within the target range of 36-37 °C in the ICU. No consciousness disorder, hypotension, increased serum potassium level, metabolic acidosis, or cola-colored urine was observed during her ICU stay. Subsequently, her general condition improved and she was discharged on day 12. Muscle biopsy after discharge was performed and provided a definitive diagnosis of MH. CONCLUSIONS: The occurrence of MH can be life-threatening, but its frequency is very low, and genetic testing and muscle biopsy are required to confirm the diagnosis. On retrospective evaluation using the malignant hyperthermia scale, the present case was almost certainly that of a patient with MH. Prompt recognition and immediate treatment with dantrolene administration and body cooling effectively reversed a potentially fatal syndrome. This was hence a valuable case of a patient with postoperative MH that led to a confirmed diagnosis by CICR.

Long-Term Outcome of Nipple Projection Maintenance After Reconstruction with Clover Flap Technique.

BACKGROUND: Nipple reconstruction using local skin flap leaves no morbidity in the healthy nipple. However, one disadvantage of this procedure is that the projection is not often maintained. There are few reports on the rate of long-term maintenance of nipple projection. This study aimed to analyze the 5-year results of clover flap (C-F) nipple reconstruction to determine whether it can be used to maintain nipple projection for long periods and to investigate the factors involved in maintenance of nipple projection. METHODS: Patients that underwent nipple-areola reconstruction using C-F after undergoing a two-stage implant-based breast reconstruction with skin-sparing mastectomy between January 2012 and December 2019 were included. The projection of the reconstructed nipple was measured annually for 5 years postoperatively, and the nipple projection maintenance rate (%) was calculated. The influence of eight factors, namely smoking, irradiation, scarred skin, flap pedicle relative to the mastectomy scar, location of the mastectomy scar, flap suturing, and flap necrosis, on nipple height were evaluated. RESULTS: Overall, 275 patients were enrolled. The average maintenance rates (%) at 1-5 years after surgery were 47.1, 39.8, 36.4, 34.6, and 33.5. Creating a well-vascularized skin flap, designing the pedicle farther away from the mastectomy scar, choosing a surgical technique involving an oblique scar on the side of the nipple by wrapping the skin flaps, and including an appropriate amount of fat tissue inside the reconstructed nipple are important for nipple projection maintenance. CONCLUSION: Nipples reconstructed using the C-F technique on the artificial mound achieve excellent long-term result. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each submission to which evidence-based medicine rankings are applicable. This excludes review articles, book reviews, and manuscripts that concern basic science, animal studies, cadaver studies, and experimental studies. For a full description of these evidence-based medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Induction of antibody responses in mice immunized intranasally with Type I interferon as adjuvant and synergistic effect of chitosan.

Type I IFNs are a range of host-derived molecules with adjuvant potential; they have been used for many years in the treatment of cancer and viral hepatitis. Therefore, the safety of IFNs for human use has been established. In this study, we evaluated the mucosal adjuvanticity of IFN-ß administered intranasally to mice with diphtheria toxoid, and suggested a method to improve its adjuvanticity. When IFN-ß alone was used as a mucosal adjuvant, no clear results were obtained. However, simultaneous administration of IFN-ß and chitosan resulted in an enhancement of the specific serum immunoglobulin G (IgG) and IgA antibody responses, the mucosal IgA antibody response, and antitoxin titers. Furthermore, the intranasal administration of IFN-α alone resulted in a greater increase in antibody titer than IFN-ß, and a synergistic effect with chitosan was also observed. These findings suggest that intranasal administration of chitosan and Type I IFNs may display an effective synergistic mucosal adjuvant activity.

Salvage mastectomy for local recurrence and second ipsilateral autologous breast reconstruction using a perforator flap from a different donor site.

Only one case of second ipsilateral autologous reconstruction for the same breast that had previously undergone reconstruction has been reported. Here we present a patient who underwent breast reconstruction twice using free flap from different donor sites, using a buttock after a local recurrence following the previous reconstruction with a lower abdomen.

A New Local Flap Nipple Reconstruction Technique Using Dermal Bridge and Preoperatively Designed Tattoo.

BACKGROUND: Nipple-areolar reconstruction is the final step in breast reconstruction. Reconstruction using local flaps and tattooing is useful in cases of bilateral reconstruction, a small nipple-areolar complex (NAC) as the donor site, and avoiding disturbance of the normal side and other body parts. However, this method can cause projection loss and color fading of the nipple. Moreover, the breast mound is reconstructed with an implant. METHODS: We performed nipple-areolar reconstruction of 90 nipples using clover-designed flaps oriented at 120 degrees and tattooing after breast silicone implantation in 64 women. The tattoo was designed before flap operation and stained darker. Following donor site closure, a dermal flap was made as a bridge for nipple support. The nipple space was separated by the dermal flap from the breast mound and was filled with subcutaneous tissue. The size of the reconstructed nipple projection was measured postoperatively and 1 year later. The projection maintenance rate was calculated. RESULTS: The heights of the nipple projection were 11.3 ± 1.8 mm (95% confidence interval [CI]: 10.9-11.7) just after the operation and 6.09 ± 2.4 mm (95% CI: 5.6-6.6) 1 year later. The actual range of nipple projection between these 2 heights was 5.2 ± 2.4 mm (95% CI: 4.7-5.7). The maintenance rate of the reconstructed nipple projection after 12 months was 54.1 ± 20.9 (95% CI: 49.7-58.5). The nipple color was maintained for over a year. CONCLUSIONS: Our nipple-areolar reconstruction technique could maintain the projection and color of the reconstructed nipple for a long period. Good outcomes were obtained in this implant-based breast reconstruction.

The optimal reconstruction size of nipple-areola complex following breast implant in breast cancer patients.

BACKGROUND: Changes in the areola size after reconstruction of the nipple-areola complex (NAC) following mastectomy and breast reconstruction with a silicon implant in primary breast cancer patients have not been well examined. This study aimed to investigate time-dependent changes in the size of the donor and graft NACs and to assess clinical factors influencing these changes. METHODS: Fifty-eight consecutive patients who underwent nipple-areola reconstruction were retrospectively evaluated. Nipple-areola diameter was measured immediately after the NAC reconstruction and at each follow-up visit for at least 36 months. RESULTS: The donor NAC constituted 81 % of the graft NAC at the time of operation. The size of the donor NAC gradually increased by up to 36.8 % after the operation. The size of the graft NAC showed a decrease by 4.5 % at 7 months, followed by recovery to the initial value. The ratio of the donor site size to the graft site size was increased at month 1 and then showed a gradual decrease to 1.08 at 36 months. A history of mastopexy or reduction for the donor site was independent factors associated with changes in the NAC size. CONCLUSIONS: To achieve symmetry, the diameter of the donor NAC immediately after the reconstruction should be at least 20 % smaller than that of the graft NAC, especially for patients without a history of additional operations.

Toxigenic Corynebacterium ulcerans isolated from a wild bird (ural owl) and its feed (shrew-moles): comparison of molecular types with human isolates.

BACKGROUND: Corynebacterium ulcerans is a pathogen causing diphtheria-like illness to humans. In contrast to diphtheria by Corynebacterium diphtheriae circulating mostly among humans, C. ulcerans infection is zoonotic. The present study aimed to clarify how a zoonotic pathogen C. ulcerans circulates among wild birds and animals. RESULTS: By screening 380 birds, a single strain of toxigenic C. ulcerans was isolated from a carnivorous bird, ural owl (Strix uralensis). The bacterium was also isolated from two individuals of Japanese shrew-mole (Urotrichus talpoides), a food preference of the owl. Analysis by ribotyping showed that the owl and mole isolates were classified in a group, suggesting that C. ulcerans can be transmissible among wild birds and their prey animals. Moreover, our isolates were found to belong to a group of previously reported C. ulcerans isolates from dogs and a cat, which are known to serve as sources for human infection. CONCLUSION: The findings suggest that the shrew-mole may be a potential reservoir of a zoonotic pathogen C. ulcerans.

Toxigenic Corynebacterium ulcerans isolated from a hunting dog and its diphtheria toxin antibody titer.

Toxigenic Corynebacterium ulcerans is a zoonotic pathogen that produces diphtheria toxin and causes a diphtheria-like illness in humans. The organism is known to infect and circulate among dogs, which can then transmit it to humans. Furthermore, previous studies have found that C. ulcerans is carried by wild animals, including game animals. In the present study, we tested hunting and companion dogs for the presence of toxigenic C. ulcerans and succeeded in isolating the bacterium from a hunting dog. Moreover, several hunting dogs had serum diphtheria antitoxin titers that were higher than the titers required for protection in humans, suggesting a history of exposure to toxigenic Corynebacterium strains. Notably, ribotyping, pulsed-field gel electrophoresis and tox gene sequencing demonstrated that the isolate from the hunting dog clustered with previously characterized C. ulcerans strains isolated from wild animals, as opposed to groups of isolates from humans and companion dogs. Interestingly, the wild animal cluster also contains an isolate from an outdoor breeding dog, which could have formed a bridge between isolates from wild animals and those from companion dogs. The results presented herein provide insight into the mechanism by which the zoonotic pathogen C. ulcerans circulates among wild animals, hunting and companion dogs, and humans.

Anatomy of the superficial layer of superficial fascia around the nipple-areola complex.

BACKGROUND: The periareolar incision is the preferred method for mammaplasty because of the minimal scarring, and suturing of the superficial fascial system (SFS) is useful for avoiding hypertrophic scarring. In this report, we describe the anatomical location of the SFS around the nipple-areolar complex (NAC) and its histological structure. METHODS: To define the location of the SFS, 20 healthy women were assessed by ultrasonography, and sections of the NAC of 10 female cadavers were examined under a light microscope. RESULTS: Ultrasonographic examination of sagittal sections of the breast revealed a hyperdense line immediately beneath the skin, which ran parallel with the skin and turned under the NAC. At the turning point, the line thickened to an average of 3.09 mm. The distance between the nipple and the thickest point of the hyperdense line was 10.14 mm on average. Histological structures of the line were collagen and elastic fibers containing smooth muscles that were connected to the dermis and adipose tissue. At the turning point, nerves, blood vessels, and mammary ducts were irregularly observed in the area of collagen and elastic fibers. These structures were intermingled, and the fiber bundle was very thick. CONCLUSIONS: The thickest area of the turning point is an area of the superficial layer of superficial fascia, which is a key structure around the NAC. The detailed anatomical data shown in our study provide good morphological landmarks for the closure of periareolar incisions. NO LEVEL ASSIGNED: This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors http://www.springer.com/00266.

Increased wound pH as an indicator of local wound infection in second degree burns.

Wound pH affects a number of important factors in wound healing. It is known that the pH of the skin surface of healthy adults and children is 4.2-5.6 and that it decreases with the lapse of epithelialization. We measured the pH of the exudates from second degree burns in 26 cases. Among these, local burn wound infection developed in 6 cases. The causative organisms were Staphylococcus aureus in 2 cases and Staphylococcus epidermidis in 4 cases. The maximum pH value measured was 10.0 and the minimum was 5.0 for all samples. There were no differences in the initial measurements of pH between the non-infected cases and the local-infected cases. In cases of local infection, the pH rose prior to the onset of clinical signs of local burn infection. By consecutive measurement of pH, early detection of local wound infection can be achieved and this is very beneficial in clinical practice. Moreover, measurement is very easy and results are available immediately. In conclusion, consecutive pH measurement of exudates is considered to be a useful indicator in the treatment of second degree burns.

Genetic characterization and comparison of Clostridium botulinum isolates from botulism cases in Japan between 2006 and 2011.

Genetic characterization was performed for 10 group I Clostridium botulinum strains isolated from botulism cases in Japan between 2006 and 2011. Of these, 1 was type A, 2 were type B, and 7 were type A(B) {carrying a silent bont/B [bont/(B)] gene} serotype strains, based on botulinum neurotoxin (BoNT) production. The type A strain harbored the subtype A1 BoNT gene (bont/A1), which is associated with the ha gene cluster. The type B strains carried bont/B5 or bont/B6 subtype genes. The type A(B) strains carried bont/A1 identical to that of type A(B) strain NCTC2916. However, bont/(B) genes in these strains showed single-nucleotide polymorphisms (SNPs) among strains. SNPs at 2 nucleotide positions of bont/(B) enabled classification of the type A(B) strains into 3 groups. Pulsed-field gel electrophoresis (PFGE) and multiple-locus variable-number tandem-repeat analysis (MLVA) also provided consistent separation results. In addition, the type A(B) strains were separated into 2 lineages based on their plasmid profiles. One lineage carried a small plasmid (5.9 kb), and another harbored 21-kb plasmids. To obtain more detailed genetic information about the 10 strains, we sequenced their genomes and compared them with 13 group I C. botulinum genomes in a database using whole-genome SNP analysis. This analysis provided high-resolution strain discrimination and enabled us to generate a refined phylogenetic tree that provides effective traceability of botulism cases, as well as bioterrorism materials. In the phylogenetic tree, the subtype B6 strains, Okayama2011 and Osaka05, were distantly separated from the other strains, indicating genomic divergence of subtype B6 strains among group I strains.