Comparison of clinical outcome between surgical treatment and particle beam therapy for pelvic bone sarcomas: A retrospective multicenter study in Japan.

BACKGROUND: Few studies have compared the clinical outcomes of patients with pelvic bone sarcomas treated surgically and those treated with particle beam therapy. This is a multicenter retrospective cohort study which compared the clinical outcomes of patients with pelvic bone sarcoma who underwent surgical treatment and particle beam therapy in Japan. METHODS: A total of 116 patients with pelvic bone sarcoma treated at 19 specialized sarcoma centers in Japan were included in this study. Fifty-seven patients underwent surgery (surgery group), and 59 patients underwent particle beam therapy (particle beam group; carbon-ion radiotherapy: 55 patients, proton: four patients). RESULTS: The median age at primary tumor diagnosis was 52 years in the surgery group and 66 years in the particle beam group (P < 0.001), and the median tumor size was 9 cm in the surgery group and 8 cm in the particle beam group (P = 0.091). Overall survival (OS), local control (LC), and metastasis-free survival (MFS) rates were evaluated using the Kaplan-Meier method and compared among 116 patients with bone sarcoma (surgery group, 57 patients; particle beam group, 59 patients). After propensity score matching, the 3-year OS, LC, and MFS rates were 82.9% (95% confidence interval [CI], 60.5-93.2%), 66.0% (95% CI, 43.3-81.3%), and 78.4% (95% CI, 55.5-90.5%), respectively, in the surgery group and 64.9% (95% CI, 41.7-80.8%), 86.4% (95% CI, 63.3-95.4%), and 62.6% (95% CI, 38.5-79.4%), respectively, in the particle beam group. In chordoma patients, only surgery was significantly correlated with worse LC in the univariate analysis. CONCLUSIONS: The groups had no significant differences in the OS, LC, and MFS rates. Among the patients with chordomas, the 3-year LC rate in the particle beam group was significantly higher than in the surgery group.

Emergence of Novel Type C Botulism Strain in Household Outbreak, Japan.

In 2021, an outbreak of food poisoning caused by Clostridium botulinum type C occurred in Kumamoto, Japan. Analysis of the isolated strain revealed that it possessed the bont/C gene and was slightly different from the reference bont/C gene. The risk for human infection with this new toxin type may be low.

Polymerase chain reaction primer sets for the detection of genetically diverse human sapoviruses.

Sapoviruses are increasingly being recognized as pathogens associated with gastroenteritis in humans. Human sapoviruses are currently assigned to 18 genotypes (GI.1-7, GII.1-8, GIV.1, and GV.1-2) based on the sequence of the region encoding the major structural protein. In this study, we evaluated 11 polymerase chain reaction (PCR) assays using published and newly designed/modified primers and showed that four PCR assays with different primer combinations amplified all of the tested human sapovirus genotypes using either synthetic DNA or cDNA prepared from human sapovirus-positive fecal specimens. These assays can be used as improved broadly reactive screening tests or as tools for molecular characterization of human sapoviruses.

Evaluation of the culture method NIHSJ-02 alternative to ISO 10272-1:2006 for the detection of campylobacter jejuni and campylobacter coli in chicken: collaborative study.

For the surveillance of the prevalence of Campylobacter jejuni and Campylobacter coli in raw chicken products in Japan, a qualitative method, National Institute of Health Sciences Japan (NIHSJ)-02, was developed as an alternative to International Organization for Standardization (ISO) 10272-1:2006. In the NIHSJ-02 culture method, the enrichment step is carried out in a reduced volume of Preston broth at 42 +/- 1 degrees C to reduce cost and space, and to prevent the overgrowth of background bacteria. To evaluate the performance of NIHSJ-02, a collaborative study was conducted, and the results obtained by NIHSJ-02 were compared with those obtained using the reference method, ISO 10272-1:2006. Fifteen laboratories participated; each examined 48 minced chicken samples consisting of test samples uninoculated, inoculated with C. jejuni at a low or high level, and inoculated with C. coli at a low level. The average probabilities of detection by NIHSJ-02 across laboratories were 0.033, 0.222, 0.678, and 0.267 in samples uninoculated, inoculated with C. jejuni at a low and high level, and with C. coli at a low level, respectively. Those by ISO 10272-1:2006 were 0.051, 0.128, 0.551, and 0.090. Significantly higher probabilities of detection were determined by NIHSJ-02 compared to ISO 10272-1:2006, except for uninoculated samples. On the other hand, significantly lower frequency of occurrence of background bacteria was observed by NIHSJ-02 (43.1%) compared with ISO 10272-1:2006 (92.6%). NIHSJ-02 showed better performance than ISO 10272-1:2006 with regard to the selective detection of C. jejuni and C. coli in chicken.

Outcomes of palliative surgery for bone metastasis of metastatic renal cell carcinoma in the era of targeted therapy.

INTRODUCTION: The introduction of tyrosine kinase inhibitors has revolutionized treatment strategies for metastatic renal cell carcinoma (RCC) and has improved survival rates. The number of patients with bone metastases from RCC requiring surgery will increase as survival rates improve. However, there is insufficient evidence to standardize the treatment of bone metastases after the introduction of targeted therapy for metastatic RCC. We aimed to determine the outcomes of palliative surgical treatment of bone metastases in the extremities of patients with metastatic RCC. MATERIALS AND METHODS: We retrospectively reviewed 26 lesions from 17 patients who underwent surgery for extremity and acetabular bone metastases and were treated with targeted therapies for advanced RCC between 2008 and 2020. The median follow-up duration was 19 months (range, 4-76). We assessed the patients' activities of daily living, quality of life, and pain and analyzed their postoperative values relative to preoperative values. Postoperative overall survival (OS), local progression-free survival (LPFS), and the factors affecting them were evaluated using the Kaplan-Meier method and log-rank test. RESULTS: The 5-year OS and LPFS rates were 39.5% and 65.6%, respectively. The factors affecting OS were sex, Katagiri score, visceral metastases, and preoperative targeted therapy, while the factors affecting LPFS were pathologic fractures and surgical technique. CONCLUSION: In this study, the postoperative outcomes of palliative surgery for bone metastases from metastatic RCC were good. We suggest that systemic treatment should be prioritized over local control for advanced bone metastasis in RCC and surgery before pathological fracture should be performed for local control.

Distribution of Human Sapovirus Strain Genotypes over the Last Four Decades in Japan: a Global Perspective.

Sapovirus (SaV) infections are a public health problem because they cause acute gastroenteritis in humans of all ages, both sporadically and as outbreaks. However, only a limited amount of SaV sequence information, especially whole-genome sequences for all the SaV genotypes, is publicly available. Therefore, in this study, we determined the full/near-full-length genomic sequences of 138 SaVs from the 2001 to 2015 seasons in 13 prefectures across Japan. The genogroup GI was predominant (67%, n = 92), followed by genogroups GII (18%, n = 25), GIV (9%, n = 12), and GV (6%, n = 9). Within the GI genogroup, four different genotypes were identified: GI.1 (n = 44), GI.2 (n = 40), GI.3 (n = 7), and GI.5 (n = 1). We then compared these Japanese SaV sequences with 3,119 publicly available human SaV sequences collected from 49 countries over the last 46 years. The results indicated that GI.1, and GI.2 have been the predominant genotypes in Japan, as well as in other countries, over at least four decades. The 138 newly determined Japanese SaV sequences together with the currently available SaV sequences, could facilitate a better understanding of the evolutionary patterns of SaV genotypes.

Clinical Outcomes and Prognostic Factors in Soft Tissue Sarcoma Patients After Unplanned Excision.

Purpose: Soft tissue sarcomas (STSs) constitute a group of rare, heterogeneous tumors representing approximately 1% of all cancers. Owing to the rarity and pathological diversity of the disease, unplanned excision (UE) has often been performed for STS, resulting in an unfavorable prognosis. This study aimed to clarify clinical outcomes and prognostic factors in STS patients who underwent UE. Patients and Methods: In a retrospective review of the medical records of patients with STS who underwent surgery at our institution between 1999 and 2015, patients were enrolled to either a UE group or a planned excision (PE) group. An analysis was then conducted to identify factors associated with prognosis after UE. Results: Of 134 patients undergoing surgery for STS, 110 were enrolled to the PE group and 24 to the UE group. The median size of the primary tumor was significantly smaller, and more lesions were located in the superficial layer in the UE group than in the PE group. In addition, plastic reconstruction after additional radical resection was required significantly more often in the UE group than in the PE group. No significant difference in overall survival, local recurrence-free survival, or disease-free survival (DFS) between the UE and PE groups was observed; however, metastasis-free survival was significantly better in the UE group. In the UE group, poorer DFS was associated with older age (≥61 years) and a larger primary tumor (≥2.9 cm). Conclusion: A prognosis similar to that in patients undergoing PE could be achieved by appropriate additional surgeries in patients initially undergoing UE. However, UE for STS should be avoided, especially in older patients and those with a larger primary tumor.

Proximal-type epithelioid sarcoma in pubic region expressing L-type amino acid transporter 1: A case report.

Proximal-type epithelioid sarcoma is an aggressive malignant soft-tissue neoplasm, a "proximal" variant of epithelioid sarcoma, resistant to multimodal therapy and involved in early tumor-related death. Pertinent treatments are, therefore, continually being explored. A 24-year-old woman with nonmetastatic proximal-type epithelioid sarcoma, originating subcutaneously on the right side of the vulva, underwent surgical resection; the lesion recurred, however, leading to death 3 months after the second surgery. Here described is a case of proximal-type epithelioid sarcoma expressing L-type amino acid transporter 1 (LAT1) that transports essential amino acids and p-borono-L-phenylalanine (BPA)-the chemical compound used in boron neutron capture therapy (BNCT)-and is highly expressed in many malignant tumors. Recently, LAT1 has drawn attention, and relevant treatments have been studied-LAT1 inhibitor and BNCT. LAT1 expression in proximal-type epithelioid sarcoma may lead to cogent treatments for the disease.

Identification and characterization of slow­cycling cells in Ewing sarcoma.

Ewing sarcoma (ES) is an aggressive primary malignant bone tumor that predominantly affects children and young adults. Multimodal treatment approaches have markedly improved the survival of patients with localized ES. However, local recurrence and distant metastasis following curative therapies remain a main concern for patients with ES. Recent studies have suggested that slow­cycling cells (SCCs) are associated with tumor progression, local recurrence and distant metastasis in various types of cancers. According to the results of these studies, it was hypothesized that SCCs may play a critical role in tumor progression, chemoresistance and local/distal recurrence in patients with ES. The present study applied a label­retaining system using carboxyfluorescein diacetate succinimidyl ester (CFSE) to identify and isolate SCCs in ES cell lines. In addition, the properties of SCCs, including sphere formation ability, cell cycle distribution and chemoresistance, in comparison with non­SCCs were investigated. RNA sequencing also revealed several upregulated genes in SCCs as compared with non­SCCs; the identified genes not only inhibited cell cycle progression, but also promoted the malignant properties of SCCs. On the whole, the present study successfully identified SCCs in ES cells through a label­retaining system using CFSE. Moreover, to the best of our knowledge, the present study is the first to describe the characteristic properties of SCCs in ES. The findings of this study, if confirmed, may prove to be useful in elucidating the underlying molecular mechanisms and identifying effective therapeutic targets for ES.

Clinical Outcome of Patients with Pelvic and Retroperitoneal Bone and Soft Tissue Sarcoma: A Retrospective Multicenter Study in Japan.

This study aimed to retrospectively analyze the clinical outcomes of patients with pelvic and retroperitoneal bone and soft tissue sarcoma (BSTS). Overall, 187 patients with BSTS in the pelvis and retroperitoneal region treated at 19 specialized sarcoma centers in Japan were included. The prognostic factors related to overall survival (OS), local control (LC), and progression-free survival (PFS) were evaluated. The 3-year OS and LC rates in the 187 patients were 71.7% and 79.1%, respectively. The 3-year PFS in 166 patients without any distant metastases at the time of primary tumor diagnosis was 48.6%. Osteosarcoma showed significantly worse OS and PFS than other sarcomas of the pelvis and retroperitoneum. In the univariate analyses, larger primary tumor size, soft tissue tumor, distant metastasis at the time of primary tumor diagnosis, P2 location, chemotherapy, and osteosarcoma were poor prognostic factors correlated with OS. Larger primary tumor size, higher age, soft tissue tumor, chemotherapy, and osteosarcoma were poor prognostic factors correlated with PFS in patients without any metastasis at the initial presentation. Larger primary tumor size was the only poor prognostic factor correlation with LC. This study has clarified the epidemiology and prognosis of patients with pelvic and retroperitoneal BSTS in Japan.

Nationwide and long-term molecular epidemiologic studies of mumps viruses that circulated in Japan between 1986 and 2017.

In Japan, major mumps outbreaks still occur every 4-5 years because of low mumps vaccine coverage (30-40%) owing to the voluntary immunization program. Herein, to prepare for a regular immunization program, we aimed to reveal the nationwide and long-term molecular epidemiological trends of the mumps virus (MuV) in Japan. Additionally, we performed whole-genome sequencing (WGS) using next-generation sequencing to assess results from conventional genotyping using MuV sequences of the small-hydrophobic (SH) gene. We analyzed 1,064 SH gene sequences from mumps clinical samples and MuV isolates collected from 25 prefectures from 1986 to 2017. The results showed that six genotypes, namely B (110), F (1), G (900), H (3), J (41), and L (9) were identified, and the dominant genotypes changed every decade in Japan since the 1980s. Genotype G has been exclusively circulating since the early 2000s. Seven clades were identified for genotype G using SH sequence-based classification. To verify the results, we performed WGS on 77 representative isolates of genotype G using NGS and phylogenetically analyzed them. Five clades were identified with high bootstrap values and designated as Japanese clade (JPC)-1, -2, -3, -4, -5. JPC-1 and -3 accounted for over 80% of the total genotype G isolates (68.3 and 13.8%, respectively). Of these, JPC-2 and -5, were newly identified clades in Japan through this study. This is the first report describing the nationwide and long-term molecular epidemiology of MuV in Japan. The results provide information about Japanese domestic genotypes, which is essential for evaluating the mumps elimination progress in Japan after the forthcoming introduction of the mumps vaccine into Japan's regular immunization program. Furthermore, the study shows that WGS analysis using NGS is more accurate than results obtained from conventional SH sequence-based classification and is a powerful tool for accurate molecular epidemiology studies.

Multiplex PCR assay for identification of three major pathogenic Vibrio spp., Vibrio cholerae, Vibrio parahaemolyticus, and Vibrio vulnificus.

A multiplex PCR assay was developed based on atpA-sequence diversification for molecular identification of 3 major pathogenic Vibrio species: Vibrio cholerae, Vibrio parahaemolyticus, and Vibrio vulnificus. It specifically identified them from among 133 strains of various Vibrio species and other genera, and was applicable for testing seawater, suggesting its usefulness.

Regulatory roles of miRNAs 16, 133a, and 223 on osteoclastic bone destruction caused by breast cancer metastasis.

Osteolytic bone metastasis leads to skeletal­related events, resulting in a decline in the patient activities and survival; therefore, it is important to understand the mechanism underlying bone metastasis. Recent studies have suggested that microRNAs (miRNAs or miRs) are involved in osteoclast differentiation and/or osteolytic bone metastasis; however, the roles of miRNAs have not been elucidated. In the present study, the roles of miRNAs in bone destruction caused by breast cancer metastasis were investigated in vitro and in vivo. miR­16, miR­133a and miR­223 were transfected into a human breast cancer cell line, MDA­MB­231. The expression of osteolytic factors in conditioned medium (miR­CM) collected from the culture of transfected cells was assessed. To evaluate the effects of miRNAs on osteoclast differentiation and activities, tartrate­resistant acid phosphatase (TRAP) staining and bone resorptive assays were performed in osteoclasts following miR­CM treatment. To create in vivo bone metastasis models for histological and morphometric evaluation, miRNA­transfected MDA­MB­231 cells were transplanted into the proximal tibia of nude mice. Expression of osteolytic factors, including receptor activator for nuclear factor­κB ligand (RANKL), interleukin (IL)­1ß, IL­6, parathyroid hormone­related protein (PTHrP), and tumor necrosis factor (TNF), was increased in miR­16­CM, whereas it was decreased in both miR­133a­CM and miR­223­CM. TRAP staining and bone resorptive assays revealed that osteoclast function and activities were promoted by miR­16­CM treatment, whereas they were suppressed by miR­133a­CM and miR­223­CM. Consistent with in vitro findings, in vivo experiments revealed that the overexpression of miR­16 increased osteoclast activities and bone destruction in MDA­MB­231 cells, whereas the opposite results were observed in both miR­133a­ and miR­223­transfected MDA­MB­231 cells. Our results indicated that miR­16 promoted osteoclast activities and bone destruction caused by breast cancer metastasis in the bone microenvironment, whereas miR­133a and miR­223 suppressed them. These miRNAs could be potential biomarkers and therapeutic targets for breast cancer bone metastasis.

Chondrolipoma of the finger in a child: A case study.

Chondrolipoma is, based on the limited case reports available, an extremely rare histological variant of lipoma with the proliferation of mature adipocytes containing an area of true hyaline cartilage. Chondrolipoma is characterized by adult onset and is often identified in the breast, pharynx and tongue. The current study presents a case of chondrolipoma of the finger in an 11 year-old girl. Physical examination indicated a well-defined elastic soft mass, measuring 2.5x2 cm, on the dorsal aspect of the proximal phalanx of the left middle finger. Magnetic resonance imaging (MRI) revealed a well-circumscribed lesion with heterogeneous signal intensity. On T1- and T2-weighted images, the lesion indicated a predominantly marked hyperintense signal containing linear hypointense regions, and on fat-suppressed short-tau inversion recovery sequences, the lesion indicated a predominant hypointensity, with linear regions displaying hyperintensity. Marginal excision of the tumor was performed. Histologically, the major component of the tumor was mature adipose tissue containing a limited area of mature hyaline cartilage matrix, without lipoblasts or malignancy. The postoperative course of the patient was excellent, with no local recurrence three years after surgery. To the best of our knowledge, the current study outlines the first pediatric case of chondrolipoma arising in the finger.

Clinical Outcome of the Patients With Brain Metastasis from Soft Tissue Sarcomas.

BACKGROUND/AIM: This study aimed to evaluate the association of clinical characteristics with treatment outcomes to ascertain the appropriate treatment options for soft tissue sarcomas (STS) patients with brain metastasis (BM). PATIENTS AND METHODS: Medical records of STS patients with BM who were treated in our institutions were retrospectively reviewed, and analyzed to identify the factors associated with post-BM survival. RESULTS: Among the 509 STS patients, BM occurred in five patients (0.98%). The median survival after BM was 1.5 months. Histological subtypes of the primary lesions in the five BM patients were: two synovial sarcomas, one myxoid liposarcoma, one alveolar soft part sarcoma, and one rhabdomyosarcoma. Among the five BM patients, the post-BM survival of two patients, who underwent surgery and postoperative radiotherapy, was longer than that of the other patients (p<0.01). CONCLUSION: Combined surgery and postoperative radiotherapy effectively managed symptoms and prolonged survival in STS patients with BM.

Surgical outcomes of metastatic bone tumors in the extremities (Surgical outcomes of bone metastases).

BACKGROUND: Skeletal related events due to metastatic bone tumors markedly affect the activities of daily living (ADL) and quality of life (QOL) in cancer patients. We focused on multidisciplinary therapy for metastatic bone tumors. This study aimed to evaluate the outcomes of surgical treatment for metastatic bone tumors in the extremities. METHODS: We retrospectively reviewed 114 patients who underwent surgical treatment for metastatic bone tumors of the extremities between 2008 and 2019 and 69 patients were reassessed for more than 6 months after surgery. The most common primary tumor was renal, followed by lung, thyroid, and breast cancers. We assessed 69 patients' performance status (PS), Barthel Index (BI) for ADL, EuroQol 5 Dimensions (EQ-5D) for QOL, and numerical rating scale (NRS) for pain and analyzed these postoperative values relative to preoperative values using Friedman's test. The postoperative overall survival and the prognostic factors were evaluated using the Kaplan-Meier method, the log-rank test and Cox proportional hazards analysis. RESULTS: The 1-year overall survival rate was 59%, and the median survival time after surgery was 20 months. Primary tumor, visceral metastasis, and surgical procedure were risk factors correlated with overall survival. PS, BI, EQ-5D, and NRS improved at 3 months after surgery and these improvements were maintained for 6 months after surgery regardless of the surgical procedure. CONCLUSIONS: The significant factors affecting survival after surgical treatment for bone metastases included the primary tumor, presence of visceral metastases, and internal fixation without tumor resection or curettage. Surgical treatment for metastatic bone tumors effectively reduced pain and improved PS, ADL, and QOL postoperatively after 3 months.

Acquisition of cancer stem cell properties in osteosarcoma cells by defined factors.

BACKGROUND: Cancer stem cells (CSCs) are considered to be responsible for tumor initiation, formation, and poor prognosis of cancer patients. However, the rarity of CSCs in clinical samples makes it difficult to elucidate characteristics of CSCs, especially in osteosarcoma (OS). The aim of this study is to verify whether it is possible to generate CSC-like cells by transducing defined factors into an OS cell line. METHODS: We retrovirally transduced the Octamer-binding transcription factor 3/4 (OCT3/4), Kruppel-like factor 4 (KLF4), and SRY-box transcription factor 2 (SOX2) genes into the MG-63 human OS cell line (MG-OKS). Parental and GFP-transduced MG-63 cells were used as negative control. We assessed the properties of the generated cells in vitro and in vivo. Multiple comparisons among groups were made using a one-way analysis of variance (ANOVA) followed by post hoc testing with Tukey's procedure. RESULTS: MG-OKS cells in vitro exhibited the significantly increased mRNA expression levels of CSC markers (CD24, CD26, and CD133), decreased cell growth, increased chemoresistance and cell migration, and enhanced sphere formation. Notably, MG-OKS cells cultured under osteogenic differentiation conditions showed strongly positive staining for both Alizarin Red S and alkaline phosphatase, indicating osteogenesis of the cells. Gene ontology analysis of microarray data revealed significant upregulation of epidermal-related genes. Tumors derived from MG-OKS cells in vivo were significantly larger than those from other cells in µCT analysis, and immunohistochemical staining showed that Ki-67, osteocalcin, and HIF-1α-positive cells were more frequently detected in the MG-OKS-derived tumors. CONCLUSIONS: In this study, we successfully generated OS CSC-like cells with significantly enhanced CSC properties following transduction of defined factors.

Prognostic influence of the treatment approach for pulmonary metastasis in patients with soft tissue sarcoma.

Soft tissue sarcomas (STSs) are rare heterogeneous malignancies of mesenchymal origin. Pulmonary metastases develop in approximately 50% of the patients with high-grade STS, being the major cause of mortality in patients with metastatic STS. Pulmonary metastasectomy has been reported to contribute to long-term survival; however, an appropriate treatment has not been established. We aimed to identify factors associated with post-metastasis survival in STS patients with pulmonary metastasis and determine the appropriate treatment for each patient. We retrospectively reviewed the records of metastatic STS patients treated between 2000 and 2017 and analyzed the clinico-pathologic variables to identify factors associated with the survival. The median survival after pulmonary metastasis was 20.6 months, and the 1-, 3-, and 5-year survival rates were 68.6%, 36.0%, and 25.1%, respectively. The survival was significantly greater in patients who underwent pulmonary metastasectomy than in those without surgery (38.9 months vs. 10.5 months; p < 0.0001). Among those who did not undergo surgery, the survival was significantly greater in patients who received chemotherapy than in those without chemotherapy (19.1 months vs. 6.3 months, p = 0.037). Multivariate analysis identified pulmonary metastasectomy as the most important prognostic factor for post-metastasis survival (Hazard ratio 5.623; 95% Confidence Interval 2.733-11.572; p < 0.0001). In conclusion, pulmonary metastasectomy was the most important prognostic factor for post-metastasis survival in patients with metastatic STS. In addition, chemotherapy could prolong survival in patients who were not eligible for pulmonary resection. Although we should carefully weigh the risks and benefits, appropriate treatment for pulmonary metastases could contribute to long-time survival.

Surveillance of pathogens in outpatients with gastroenteritis and characterization of sapovirus strains between 2002 and 2007 in Kumamoto Prefecture, Japan.

Infectious acute gastroenteritis is an important public health problem worldwide. A total of 639 stool specimens were tested for the presence of diarrhea pathogens. The specimens were from outpatients with acute gastroenteritis who consulted the pediatric clinic in Kumamoto Prefecture, Japan, from June 2002 to December 2007. Of these, 421 (65.9%) were positive for diarrhea pathogens. Among them were norovirus (NoV) in 260 (61.8%), sapovirus (SaV) in 81 (19.2%), rotavirus in 49 (11.6%), adenovirus in 19 (4.5%), enterovirus in 13 (3.1%), astrovirus in 9 (2.1%), kobuvirus in 1 (0.2%), and bacterial pathogens in 11 (2.6%). Mixed infection (co-infection of viruses) was found in 22 (5.2%) of the 421 pathogen-positive stool samples. NoV was the most prevalent pathogen throughout the study period; however, the SaV detection rate was unexpectedly high and was found to be the secondary pathogen from 2005 to 2007. Genetic analysis of SaV with 81 strains demonstrated that SaV strains belonging to genogroup IV emerged in 2007, and dynamic genogroup changes occurred in a restricted geographic area. This study showed that SaV infection is not as rare as thought previously.

Efficiency of real-time polymerase chain reaction assay to detect Vibrio vulnificus in seawater.

The growth of Vibrio vulnificus in an enriched culture of seawater during the summer in Japan was monitored by a plating technique used as the culture method and a real-time polymerase chain reaction (PCR) assay as the molecular method. V. vulnificus was detected by the real-time PCR assay in the samples of August and September but not by the culture method. Vibrio parahaemolyticus, however, was detected among all of the samples with both the culture method and real-time PCR assay. In the analysis of the bacterial populations in enrichment culture, it was demonstrated that the growth of V. vulnificus on agar media was inhibited by the rapid growth of V. parahaemolyticus after 4h of incubation and the 100 times larger initial populations of bacteria other than V. vulnificus and V. parahaemolyticus. These findings demonstrate that V. vulnificus detection by culture methods is a failure, and molecular methods are effective and detect V. vulnificus accurately.