Whole-genome sequencing analysis of molecular epidemiology and silent transmissions causing meticillin-resistant Staphylococcus aureus bloodstream infections in a university hospital.

BACKGROUND: The emergence of novel genomic-type clones, such as community-associated meticillin-resistant Staphylococcus aureus (MRSA) and livestock-associated MRSA, and their invasion into hospitals have become major concerns worldwide; however, little information is available regarding the prevalence of MRSA in Japan. Whole-genome sequencing (WGS) has been conducted to analyse various pathogens worldwide. Therefore, it is important to establish a genome database of clinical MRSA isolates available in Japan. AIM: A molecular epidemiological analysis of MRSA strains isolated from bloodstream-infected patients in a Japanese university hospital was conducted using WGS and single-nucleotide polymorphism (SNP) analysis. Additionally, through a review of patients' clinical characteristics, the effectiveness of SNP analysis as a tool for detecting silent nosocomial transmission that may be missed by other methods was evaluated in diverse settings and various time points of detection. METHODS: Polymerase-chain-reaction-based staphylococcal cassette chromosome mec (SCCmec) typing was performed using 135 isolates obtained between 2014 and 2018, and WGS was performed using 88 isolates obtained between 2015 and 2017. FINDINGS: SCCmec type II strains, prevalent in 2014, became rare in 2018, whereas the prevalence of SCCmec type IV strains increased from 18.75% to 83.87% of the population, and became the dominant clones. Clonal complex (CC) 5 CC8 and CC1 were detected between 2015 and 2017, with CC1 being dominant. In 88 cases, SNP analyses revealed nosocomial transmissions among 20 patients which involved highly homologous strains. CONCLUSIONS: Routine monitoring of MRSA by whole-genome analysis is effective not only for gaining knowledge regarding molecular epidemiology, but also for detecting silent nosocomial transmission.

Advances in tooth agenesis and tooth regeneration.

The lack of treatment options for congenital (0.1%) and partial (10%) tooth anomalies highlights the need to develop innovative strategies. Over two decades of dedicated research have led to breakthroughs in the treatment of congenital and acquired tooth loss. We revealed that by inactivating USAG-1, congenital tooth agenesis can be successfully ameliorated during early tooth development and that the inactivation promotes late-stage tooth morphogenesis in double knockout mice. Furthermore, Anti- USAG-1 antibody treatment in mice is effective in tooth regeneration and can be a breakthrough in treating tooth anomalies in humans. With approximately 0.1% of the population suffering from congenital tooth agenesis and 10% of children worldwide suffering from partial tooth loss, early diagnosis will improve outcomes and the quality of life of patients. Understanding the role of pathogenic USAG-1 variants, their interacting gene partners, and their protein functions will help develop critical biomarkers. Advances in next-generation sequencing, mass spectrometry, and imaging technologies will assist in developing companion and predictive biomarkers to help identify patients who will benefit from tooth regeneration.

Surveillance of multi-drug resistance phenotypes in Staphylococcus aureus in Japan and correlation with whole-genome sequence findings.

BACKGROUND: Antimicrobial resistance in Staphylococcus aureus imposes a high disease burden. Both phenotypic and genotypic monitoring are key to understanding and containing emerging resistant strains. AIM: Phenotypic monitoring of emerging resistance in S. aureus and correlation of priority strain phenotypes with whole-genome sequencing (WGS) findings. METHODS: Antimicrobial susceptibility test results of >40,000 isolates from 213 participating hospitals from 2011 to 2019 were exported from the national Japan Nosocomial Infections Surveillance (JANIS) database. Longitudinal and geographic distribution and prevalence of distinct multi-drug resistance phenotypes ('resistance profiles') of S. aureus were examined among hospitals and prefectures. We further conducted a genome sequence analysis of strains with specific resistance profiles of concern. FINDINGS: The overall prevalence of meticillin-resistant S. aureus (MRSA) decreased from 40.3% to 35.1% from 2011 to 2019. However, among dozens of S. aureus resistance profiles, only one profile of a type of MRSA, exhibited a statistically significant increase in inpatient frequency, exceeding 10% during the nine years. This MRSA profile showed resistance to oxacillin, erythromycin and levofloxacin. Analysis of WGS results of S. aureus isolates with this phenotype revealed that most belonged to clonal complex 8, and all carried SCCmec IV, typical of community-acquired MRSA. CONCLUSION: Tracking distinct resistance profiles deepened our understanding of the overall decrease in MRSA and led to recognition of the emergence of a new resistance phenotype. This study provides a model for future epidemiological research on antimicrobial resistance correlating multi-drug resistance phenotypes with selective genome sequencing, which can be applied to other bacterial species.

Impact of the COVID-19 pandemic on the surveillance of antimicrobial resistance.

BACKGROUND: The impact of the coronavirus disease (COVID-19) pandemic on antimicrobial resistance (AMR) is a major concern. AIM: To compare the number of patients and isolation rate of antimicrobial-resistant bacteria before and after the beginning of the COVID-19 pandemic using the comprehensive national surveillance data. METHODS: We utilized comprehensive surveillance data, collected in the Japan Nosocomial Infections Surveillance programme, which included a total of 16.7 million samples of 5.9 million tested patients from >1300 hospitals. We compared the number of patients and isolation rate of five bacteria between 2019 and 2020, including antimicrobial-susceptible and -resistant bacteria of Staphylococcus aureus, Streptococcus pneumoniae, Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa. FINDINGS: The number of patients and isolation rate of S. aureus and meticillin-resistant S. aureus decreased slightly; those of S. pneumoniae and penicillin-resistant S. pneumoniae decreased by 60%; and those of third-generation cephalosporin-resistant K. pneumoniae increased. The isolation rate of the remaining bacteria apparently increased, although the number of patients decreased. This was due to a substantial decrease in the total number of tested patients (the denominator of the isolation rate), which was larger than that of the number of patients (the numerator of the isolation rate). Consistent results were obtained when the same data were re-aggregated using the procedure of the World Health Organization Global Antimicrobial Resistance Surveillance System, demonstrating the general importance of this problem. CONCLUSION: Surveillance data during the COVID-19 pandemic must be carefully interpreted based on examination of the numerator, denominator and background factors that affect the denominator.

Anti-USAG-1 therapy for tooth regeneration through enhanced BMP signaling.

Uterine sensitization-associated gene-1 (USAG-1) deficiency leads to enhanced bone morphogenetic protein (BMP) signaling, leading to supernumerary teeth formation. Furthermore, antibodies interfering with binding of USAG-1 to BMP, but not lipoprotein receptor-related protein 5/6 (LRP5/6), accelerate tooth development. Since USAG-1 inhibits Wnt and BMP signals, the essential factors for tooth development, via direct binding to BMP and Wnt coreceptor LRP5/6, we hypothesized that USAG-1 plays key regulatory roles in suppressing tooth development. However, the involvement of USAG-1 in various types of congenital tooth agenesis remains unknown. Here, we show that blocking USAG-1 function through USAG-1 knockout or anti-USAG-1 antibody administration relieves congenital tooth agenesis caused by various genetic abnormalities in mice. Our results demonstrate that USAG-1 controls the number of teeth by inhibiting development of potential tooth germs in wild-type or mutant mice missing teeth. Anti-USAG-1 antibody administration is, therefore, a promising approach for tooth regeneration therapy.

Third Dentition Is the Main Cause of Premolar Supernumerary Tooth Formation.

While the prevalence of supernumerary teeth (ST) is high in permanent dentition, the etiology of ST in humans remains unclear. However, multiple murine models of ST have elaborated on dated mechanisms traditionally ascribed to ST etiology: one involves the rescue of rudimental teeth, and the second considers the contribution of odontogenic epithelial stem cells. It remains unclear whether these mechanisms of ST formation in mice are applicable to humans. The third dentition is usually regressed apoptotic-that is, the teeth do not completely form in humans. Recently, it was suggested that ST result from the rescue of regression of the third dentition in humans. The present investigation evaluates the proportion of collected general ST cases that evinced a third dentition based on the clinical definition of ST derived from the third dentition. We also investigated the contribution of SOX2-positive odontogenic epithelial stem cells to ST formation in humans. We collected 215 general ST cases from 15,008 patients. We confirmed that the general characteristics of the collected ST cases were similar to the results from previous reports. Of the 215 cases, we narrowed our analysis to the 78 patients who had received a computed tomography scan. The frequency of ST considered to have been derived from the third dentition was 26 out of 78 cases. Evidence of a third dentition was especially apparent in the premolar region, was more common in men, and was more likely among patients with ≥3 ST. SOX2-positive odontogenic epithelial stem cells within the surrounding epithelial cells of developing ST were observed in non-third dentition cases and not in third dentition cases. In conclusion, the third dentition is the main cause of ST in humans. The odontogenic epithelial stem cells may contribute to ST formation in cases not caused by a third dentition.

Phenotypes of CCAAT/enhancer-binding protein beta deficiency: hyperdontia and elongated coronoid process.

OBJECTIVES: This investigation aimed to conduct a case-control study of mandibular morphology and dental anomalies to propose a relationship between mandibular/dental phenotypes and deficiency of CCAAT/enhancer-binding protein beta (CEBPB). MATERIALS AND METHODS: Skulls of CEBPB(-/-), CEBPB(+/-) and CEBPB(+/+) mice were inspected with micro-computed tomography. Mandibular morphology was assessed with a method of Euclidean distance matrix analysis. RESULTS: Elongation of the coronoid process was identified in CEBPB(+/-) (P ≤ 0.046) and CEBPB(-/-) 12-month-olds (P ≤ 0.028) but not in 14-day-olds (P ≥ 0.217) and 0-day-olds (P ≥ 0.189) of either genotype. Formation of supernumerary teeth in CEBPB(-/-) adult mice was demonstrated (χ(2) = 6.00, df = 1, P = 0.014). CONCLUSIONS: CEBPB deficiency was related to elongation of the coronoid process and formation of supernumerary teeth. The mandibular and dental phenotypes of CEBPB deficiency were unseen by the 14th day after birth. Future investigations into the influence of CEBPB on mandibular and dental development are needed.

Hepatic venous outflow obstruction in living donor liver transplantation: balloon angioplasty or stent placement?

BACKGROUND: The incidence of hepatic venous outflow obstruction (HVOO) has been reported to be 5%-13% when a partial graft is used for orthotopic liver transplantation (OLT). HVOO leads to graft congestion, portal hypertension, and finally cirrhosis, which jeopardizes both graft and recipient survivals. In this study, we sought to identify perioperative factors influencing HVOO and to investigate conditions that require stent placement. PATIENTS AND METHODS: From February 1994 to December 2010, we performed 40 living donor liver transplantations (LDLT). HVOO occurred in 5 cases (12.5%), all of which were left lobe grafts. Because HVOO was not observed in patients with body weight (BW) <30 kg, we investigated the other 28 cases with BW >30 kg. RESULTS: There was no difference from unaffected subjects except for cold ischemic time (CIT), which was significantly longer: 86.2 ± 10.4 minutes vs 46.0 ± 4.8 minutes (P = .001). Balloon angioplasty, which was selected as the initial treatment for all stricture patients, improved 2 patients after 1 and 5 treatments, respectively, but 3 subjects underwent repeated HVOO, finally being treated with self-expandable metallic stents at 9, 6, and 10 years after LDLT, respectively. All patients finally resolved their strictures. CONCLUSION: HVOO reflects intimal hyperplasia and fibrosis at the anastomotic sites or compression and twisting of the anastomosis caused by graft regeneration. In addition, progression of chronic rejection and fibrosis are possibly responsible for late-onset HVOO. Longer CIT possibly reflects difficulties in the venoplasty before anastomosis. No bleeding or thrombosis complications were observed during dilatation among our cases. The selection of the stent size for each case and careful stent deployment are important to prevent complications. Stent placement should be considered in patients with chronic rejection who are refractory to several balloon angioplasties with early-onset or late-onset HVOO.

Importance of awareness of perioperative social and physical situations of living donors for liver transplantation.

INTRODUCTION: Transplantation in Japan still depends on living donors even after the new revised law. We must pay attention to protect living donors. PATIENTS AND METHODS: Perioperative qualities of life after living donation for liver transplantation were assessed with questionnaires including the Medical Outcomes Study 36-Item Short-Form Health Survey version 2 (SF36-v2). Nonparametric Mann-Whitney tests were used to determine statistical significance. P values<.05 were considered significant. RESULTS: Thirty-one among 33 donors answered questionnaires (93.9%). The 15 men and 16 women of average age of 39.7 years had a median hospital stay of 16 days and median duration after surgery of 78 months. Ten of 33 (35.7%) donors considered themselves to be the only possibility. The decision to a donor was established prior to informed consent in 23 donors (74.1%). Six months were required for them to experience a full recovery after donor surgery. Hamilton depression/anxiety score was significantly increased among donors who considered themselves to be the only possibility or those who had decided prior to informed consent. SF36-v2 revealed a significant decrease in social functioning among donors who did not have sufficient time to decide before surgery. General health was significantly decreased among donors who required more than 6 months for full recovery. Perioperative management of pain influenced general health, physical role, bodily pain, and physical functioning. CONCLUSION: We must pay attention to depression and anxiety among living donors. More care should be focused on pain control and sharing of information of postoperative courses.

Donor quality of life after living donor liver transplantation: single-institute experience.

AIM: Living donor liver transplantation (LDLT) has been widely accepted because of the severe shortage of hepatic grafts. However, the healthy donor is exposed to risks of morbidity and mortality. In this study, we analyzed medical, functional, and psychological outcomes of donors after hepatectomy for liver donation. PATIENTS AND METHODS: Among 41 donor hepatectomy cases for LDLT performed in our institute from January 1994 to May 2011, we reviewed the medical records (liver function tests, complications, etc) of 27 subjects who donated to recipients older than 12 years. We also performed a questionnaire survey based on the Japanese Short Form-36 version 2 Health Survey scales as a measure of physical and mental health, to which 31 subjects responded. RESULTS: Six of the 27 donors experienced prolonged jaundice. Their ratios of graft volume/standard donor liver volume (GV/SDLV) were higher than those of the 21 donors without prolonged jaundice (60.0% vs 41.5%). According to the questionnaires, social functioning among those having undergone emergency hepatectomy as well as general health perceptions declined in those with postoperative complications. Physical component summary declined among those having undergone emergency hepatectomy and with postoperative complications. CONCLUSION: In liver donation from a living donor, massive hepatectomy should be avoided. A ratio of GV/SDLV around 50% seems reasonable. Donors with emergency transplantations or postoperative complications must be more carefully followed after donor hepatectomy.

Liver transplantation for Wilson's disease in pediatric patients: decision making and timing.

Transplantation for Wilson's disease occupies 1/3 of the cases for metabolic diseases in Japan. At the end of 2009, 109 transplantations had been performed including three deceased donor cases in the Japanese registry. We herein discuss problems of transplantation for Wilson's disease as well as its indication, timing, and social care. We retrospectively reviewed four fulminant cases and two chronic cases who underwent living donor liver transplantation. There were two boys and two girls. Four adolescents of average age 11.3 years underwent living donor liver transplantation. Duration from onset to transplantation ranged from 10 to 23 days. Average Model for End-stage Liver Disease (MELD) score was 27.8 (range=24-31). All patients were administrated chelates prior to transplantation. MELD, New Wilson's index, Japanese scoring for liver transplantation, and liver atrophy were useful tools for transplantation decision making; however, none of them was an independent decisive tool. Clinical courses after transplantation were almost uneventful. One girl, however, developed an acute rejection episode due to noncompliance at 3 years after transplantation. All patients currently survive without a graft loss. No disease recurrence had been noted even using living related donors. Two adults evaluated for liver transplantation were listed for deceased donor liver transplantation. Both candidates developed cirrhosis despite long-term medical treatment. There were no appropriate living donors for them. There are many problems in transplantation for Wilson's disease. The indications for liver transplantation should be considered individually using some decision-making tools. The safety of the living donor should be paid the most attention.

Sporadic isolations of a multi-drug resistant Pseudomonas aeruginosa clone during a 14-month epidemic in a general hospital in Hiroshima.

BACKGROUND: During 2005-2007, we experienced sporadic isolations of multidrug-resistant (MDRP) Pseudomonas aeruginosa from wards in a general hospital in Hiroshima. The objective of this study was to analyze epidemiology relationships and the mode of spread of the strains. METHODS: Clonality was assessed using pulsed-field gel electrophoresis (PFGE) and serotyping. MICs were determined using the microdilution broth method. Investigations of the affected patients' movements and environmental sampling from the affected wards were conducted. RESULTS: An abrupt increase in MDRP isolations began at the end of 2005 and ended in February 2007. A total of 25 MDRP strains were sporadically isolated from nine wards. Fourteen strains were genotypically and serologically identical. Analysis of the patients' movements identified that six of the 14 MDRP-positive patients became positive for MDRP when they were in the intensive care unit (ICU), and two became positive after the patients moved from the ICU to another nursing unit. Four MDRP strains were isolated from patients who did not stay in the ICU and were in ward E6, which had the second highest number of isolations. In July 2006, environmental sampling of the hospital identified a toilet brush in ward E6 that was contaminated with MDRP that was genotypically and serologically identical to the clinical isolates. CONCLUSIONS: Our study suggests that the sporadic increase in MDRP isolates during 2005-2007 in the general hospital in Hiroshima was due to an epidemic of an MDRP clone. Continuity and spread of infection was probably due to cross infection and contamination in the hospital with the MDRP strain.

Topical application of Aggregatibacter actinomycetemcomitans cytolethal distending toxin induces cell cycle arrest in the rat gingival epithelium in vivo.

BACKGROUND: Aggregatibacter actinomycetemcomitans is one of the etiological pathogens implicated in the onset of periodontal disease. This pathogen produces cytolethal distending toxin (CDT) that acts as a genotoxin to induce cell cycle arrest and cellular distension in cultured cell lines. Therefore, CDT is a possible virulence factor; however, the in vivo activity of CDT on periodontal tissue has not been explored. Here, CDT was topically applied into the rat molar gingival sulcus; and the periodontal tissue was histologically and immunohistochemically examined. MATERIALS AND METHODS: Recombinant purified A. actinomycetemcomitans CDT was applied to gingival sulcus of male Wistar rats and tissue samples were immunohistochemmically examined. RESULTS: One day after application, infiltration of neutrophils and dilation of blood vessels in the gingival connective tissue were found. At day three, desquamation and detachment of cells in the junctional epithelium was observed. This abrasion of junctional epithelium was not observed in rats treated with mutated CDT, in which a His274Ala mutation is present in the CdtB subunit. This indicates the tissue abrasion may be caused by the genotoxicity of CdtB. Expression of the proliferating cell nuclear antigen (PCNA), a marker for proliferating cells, was significantly suppressed using CDT treatment in the junctional epithelium and gingival epithelium. CONCLUSION: Using the rat model, these data suggest CDT intoxication induces cell cycle arrest and damage in periodontal epithelial cells in vivo.

Clonal distribution of enterotoxigenic Staphylococcus aureus on handles of handheld shopping baskets in supermarkets.

AIMS: Shopping carts and handheld shopping baskets in supermarkets are subject to accidental bacterial contamination through contacts with a variety of food. We investigated the prevalence of Staphylococcus aureus on the handles of handheld shopping baskets in four supermarkets distantly located in Osaka district, Japan. METHODS AND RESULTS: Fifty two strains of Staph. aureus were isolated from 760 basket handles. Among these, six strains were positive for staphylococcal enterotoxin B (SEB) production, representing 12% of total. This SEB producer ratio is considerably higher than among Staph. aureus isolated from nasal swabs of the supermarket workers (2%) and from independently collected clinical specimens (4%). These SEB-producing Staph. aureus strains from the basket handles are clonal and belong to ST12. Coagulase typing showed that they are in group VII, which is the most common cause of food poisoning in Japan. Biofilm assays indicated that SEB gene (seb)-positive strains including this clone produced a significantly higher amount of biofilm than seb-negative strains. CONCLUSIONS: The frequent isolation of seb-positive Staph. aureus on shopping basket handles raises the possibility that they could be a hidden reservoir for Staph. aureus with a potential to cause food poisoning and draws attention to the importance of shopping basket sanitation.

Application of self-efficacy theory in dental clinical practice.

In clinical practice, self-efficacy refers to how certain a patient feels about his or her ability to take the necessary action to improve the indicators and maintenance of health. It is assumed that the prognosis for patient behaviour can be improved by assessing the proficiency of their self-efficacy through providing psychoeducational instructions adapted for individual patients, and promoting behavioural change for self-care. Therefore, accurate assessment of self-efficacy is an important key in daily clinical preventive care. The previous research showed that the self-efficacy scale scores predicted patient behaviour in periodontal patients and mother's behaviour in paediatric dental practice. Self-efficacy belief is constructed from four principal sources of information: enactive mastery experience, vicarious experience, verbal persuasion, and physiological and affective states. Thus, self-efficacy can be enhanced by the intervention exploiting these sources. The previous studies revealed that behavioural interventions to enhance self-efficacy improved oral-care behaviour of patients. Therefore, assessment and enhancement of oral-care specific self-efficacy is important to promote behaviour modification in clinical dental practice. However, more researches are needed to evaluate the suitability of the intervention method.

Drug susceptibility and clonality of methicillin-resistant Staphylococcus epidermidis in hospitalized patients with hematological malignancies.

PURPOSE: To evaluate the clonal relatedness and drug susceptibility of Streptococcus epidermidis isolated from hematological patients. METHODS: All S. epidermidis isolated from hematological patients who developed bloodstream infections between June 2005 and December 2007 were included. The clonal relationship was tested by means of pulsed-field gel electrophoresis (PFGE) analysis. RESULTS: Fifteen methicillin-resistant S. epidermidis (MRSE) isolates were examined from patients' blood culture samples. Two subgroups that differed approximately by 40% in their PFGE banding were identified. In clinical practice, two cases were cured with cephalosporin only, thus demonstrating sensitivity of the strains to beta-lactam antibiotics. CONCLUSIONS: Our results represent two significant findings. One is the major capability of MRSE to colonize patients. The other is that some MRSE isolates proved to be sensitive to clindamycin, minocycline, and cephalosporin, so that using antibiotics to which MRSE is sensitive as first-line therapy can avoid the need for vancomycin in clinical settings.

Automutanolysin disrupts clinical isolates of cariogenic streptococci in biofilms and planktonic cells.

INTRODUCTION: Dental caries remains one of the most common chronic infectious diseases throughout the world. The formation of dental plaque is one of the caries risk factors. As a consequence, the removal of plaque may reduce the incidence of caries development. We identified an autolysin produced by Streptococcus mutans named auto-mutanolysin (Aml). Aml selectively lyses S. mutans and Streptococcus sobrinus. The specificity towards these cariogenic bacteria suggests that Aml may be used to prevent dental caries. Here, with the aim towards therapeutic application, we investigated the lytic activity of Aml against clinical isolates of S. mutans and S. sobrinus using planktonic cells and biofilms. METHODS: Planktonic cell suspensions and biofilms of clinically isolated streptococci were treated with Aml in the absence or the presence of Triton X-100. The lytic activity of Aml was monitored as the change in turbidity. The disruption of biofilms was evaluated by detecting the released DNA by polymerase chain reaction and observing the alteration of optical density of treated biofilms. RESULTS: Triton X-100 enhances the lytic ability of Aml. Using planktonic cells, Aml had various lysis levels against clinical strains. Repeated Aml treatment showed disruption of the biofilm using the representative clinical strains. CONCLUSION: Our study demonstrates that Aml has an ability to lyse planktonic and biofilm cells of clinically isolated mutans streptococci in the presence of Triton X-100. These results suggest the possibility of using Aml as an alternative or additional approach for caries prevention.

Detection of a single bacterial cell using a 16S ribosomal RNA-specific oligonucleotide probe designed to investigate periodontal pathogens.

INTRODUCTION: The current detection methods for periodontopathogens mainly use polymerase chain reactions. However, there are few methods available for visualizing the bacteria that impact on patients with periodontal disease for use in health education. The purpose of this study was to develop a specific detection method to visualize periodontopathogenic bacteria. METHODS: Fluorescently-labeled oligonucleotide probes directed to specific 16S ribosomal RNA (rRNA) sequences of Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans were synthesized. Cultured individual bacterial species were fixed with 4% paraformaldehyde and smeared on glass slides. Fluorescein isothiocyanate-labeled oligonucleotide probes were hybridized under stringent conditions with smeared whole cells, and then probe specificity was investigated by epifluorescence microscopy. RESULTS: Comparatively long (50-mer) oligonucleotide probes for P. gingivalis and A. actinomycetemcomitans were designed. These probes clearly hybridized with 16S rRNA of the target species in situ and single bacterial cells were detectable visually. The probes exhibited no cross-hybridization against the additional organisms that were closely related to the target species. CONCLUSIONS: The fluorescence in situ hybridization technique is a specific and reliable method by which to visually identify the target organisms. The oligonucleotide probes designed in this study will be useful for detecting P. gingivalis and A. actinomycetemcomitans populations.

Timing for orthotopic liver transplantation in children with biliary atresia: a single-center experience.

INTRODUCTION: Biliary atresia is the most common indication for orthotopic liver transplantation (OLT) in childhood. The purpose of this study was to determine predictive prognostic factors for children with biliary atresia related to the timing for OLT within 15 months after hepatoportoenterostomy (HPE). PATIENTS AND METHODS: We retrospectively analyzed the medical records of 25 children (7 boys and 18 girls) who underwent HPE because of biliary atresia between January 1990 and December 2005 at our center. Data examined included age and pathologic findings at HPE, Pediatric End-Stage Liver Disease score at first admission, whether phototherapy was given, liver function test results and total bilirubin level before and 30 days after HPE, and number of cholangitis events. RESULTS: Twelve children were alive with their native liver, 8 had undergone living donor OLT (all children alive), and 5 had died without OLT. Five- and 10-year survival rates without OLT after HPE were 47.4% and 26.3%, respectively. At univariate analysis, the predictive prognostic factors for children with biliary atresia were total bilirubin level at 30 days after HPE and Pediatric End-Stage Liver Disease score before HPE. At multivariate analysis, the only prognostic factor was total bilirubin level at 30 days after HPE. CONCLUSIONS: In this study, the predictive prognostic factor was total bilirubin level at 30 days after HPE. Orthotopic liver transplantation within 15 months after HPE is needed in children with biliary atresia with a high total bilirubin level at 30 days after HPE.

Living donor liver transplantation for a child with recurrent pediatric adult-type hepatocellular carcinoma.

INTRODUCTION: Pediatric hepatocellular carcinoma (HCC) is an uncommon disease with a poor prognosis. There are few reports about liver transplantation for pediatric adult-type HCC. We experienced a case of living donor liver transplantation (LDLT) for a child with recurrent pediatric adult-type HCC. CASE REPORT: A 12-year-old boy was admitted to the Department of Pediatrics in our institution due to HCC in May 2005. He underwent hepatectomy after 3 courses of chemotherapy in July 2005. After the operation, he had 2 more courses of the same chemotherapy. His posttheraputic course was uneventful for 1 year. However, his alpha-fetoprotein level increased and a computed tomography (CT) scan showed recurrent tumor in his remnant liver in October 2006. He underwent another chemotherapy session immediately. However, CT revealed multiple liver tumors after chemotherapy in December 2006. His mother requested to be an LDLT donor, which was performed on January 23, 2007. The donor operation was a right hepatic lobectomy. The postoperative course of the donor was unremarkable and she has now returned to work. The recipient's posttransplantation course was uneventful and he was discharged at postoperative day 53 and is currently doing well. CONCLUSION: Liver transplantation in conjunction with chemotherapy may have an increasing role in the management of pediatric HCC.