Triple-drug combination therapy versus six-month proton pump inhibitor monotherapy in non-Helicobacter pylori Helicobacter eradication, and hyperacid environment preference of Helicobacter suis: a clinical study.

BACKGROUND: At present, eradication regimens for non-Helicobacter pylori Helicobacter (NHPH) have not been established yet. We investigated effectiveness of the standard triple-drug combination therapy for Helicobacter pylori eradication and of a proton pump inhibitor (PPI) monotherapy in eradication of NHPH. METHODS: Subjects were the patients who were diagnosed with NHPH-infected gastritis based on microscopic findings, helical-shaped organisms obviously larger than Helicobacter pylori, in the gastric mucosal specimens using Giemsa staining at Kenwakai Hospital between November 2010 and September 2021, whose NHPH species were identified by polymerase chain reaction (PCR) analysis of urease genes in endoscopically-biopsied samples, and who consented to NHPH eradication with either the triple-drug combination therapy for one week or a PPI monotherapy for six months. Six months after the completion of eradication, its result was determined with esophagogastroduodenoscopy, microscopic examination, and PCR analysis. In cases of unsuccessful eradication, a second eradication with the other therapy was suggested to the patient. RESULTS: PCR analysis detected NHPH in 38 patients: 36 as Helicobacter suis and two as Helicobacter heilmannii/Helicobacter ailurogastricus. Fourteen Helicobacter suis-infected and one Helicobacter heilmannii/Helicobacter ailurogastricus-infected patients requested eradication therapy. The triple-drug combination therapy succeeded in four of five patients, while the PPI monotherapy succeeded in five of 10 patients. Three of five patients who had been unsuccessful with the latter therapy requested the triple-drug combination therapy as the second eradication and all three were successful. In total, the triple-drug combination therapy succeeded in seven out of eight (87.5%) attempted cases, while the PPI monotherapy in five out of 10 (50%) attempted cases. CONCLUSIONS: In NHPH eradication, the triple-drug combination therapy was considered to be effective to some extent and to become the first-line therapy. While, although less successful, PPI monotherapy appeared to be a potentially promising option particularly for patients with allergy or resistance to antibiotics. Effectiveness of PPI monotherapy may be attributed to hyperacid environment preference of Helicobacter suis and PPI's acid-suppressive effect. Additionally, male predominance in NHPH-infected gastritis patients may be explained by gender difference in gastric acid secretory capacity. However, further evidence needs to be accumulated. STUDY REGISTRATION: This study was approved by the Research Ethics Committee of Kenwakai Hospital (No. 2,017,024).

Four cases of non-Helicobacter pylori Helicobacter-infected gastritis with duodenal spiral bacilli.

BACKGROUND: Non-Helicobacter pylori Helicobacter (NHPH) is rarely detected in duodenal mucosa due to its preference for slightly acidic environments. Here, we report four cases of NHPH-infected gastritis with duodenal spiral bacilli, potentially NHPH, indicating the possibility of duodenal mucosal infection. CASE PRESENTATION: In every case, gastric mucosa showed endoscopic findings characteristic of NHPH-infected gastritis, and a mucosal biopsy was taken from the duodenal bulb; spiral bacilli were identified under microscopy using Giemsa staining. Case 1, a 46-year-old man, had diffuse spotty redness, mucosal edema, and multiple tiny erosions in the duodenal bulb, along with larger erosions in the second portion of the duodenum upon endoscopic examination. Histopathologically, moderate infiltration of mononuclear cells and neutrophils in the lamina propria and gastric epithelial metaplasia were observed. Case 2, a 54-year-old man, showed an elevated lesion, 1 cm in diameter, with multiple red spots and a few tiny erosions in the duodenal bulb. Histopathologically, mild inflammatory cell infiltration and gastric epithelial metaplasia were observed. In Case 3, a 52-year-old man, endoscopy revealed a flat elevated lesion, 7 mm in diameter, with multiple red spots and a few tiny erosions in the anterior wall of the duodenal bulb. Histopathologically, we observed moderate inflammatory cell infiltration in the gastric antrum and gastric epithelial metaplasia in the duodenal bulb. Case 4, a 40-year-old man, showed mild spotty redness in the duodenal bulb. Histopathologically, mild mononucleocyte infiltration and gastric epithelial metaplasia were observed. A single spiral bacillus was observed in Case 4 by microscopy. In all but Case 2, Helicobacter suis was identified in the gastric juice by polymerase chain reaction analysis. CONCLUSIONS: Spiral bacilli resembling NHPH may infect the duodenal mucosa, particularly the bulb, causing inflammation. Gastric contents entering the duodenum may reduce the intraduodenal pH, promoting NHPH survival and proliferation.

External quality control survey on identification of microorganisms using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry（ MALDI-TOF MS） is a bacterial typing tool that was approved as a medical device in 2011. However, external accuracy control examination of bacterial typing using mass spectrometry is still only performed on a small scale. In this study, E. faecium and S. maltophilia were selected and tested according to established procedures using Score Values at 228 institutions. The Score Values for MALDI Biotyper were 2.43±0.08 for E. faecium and 2.38±0.08 for S. maltophilia; and those for VITEK MS/PRIME were 99.9±0.0 for E. faecium and S. maltophilia. These results suggest that it is useful to evaluate external accuracy control with Score Values using the procedures we have developed.

Diagnosis by combination of endoscopic findings helps differentiate non-Helicobacter pylori Helicobacter-infected gastritis from Helicobacter pylori-infected gastritis.

BACKGROUND: The characteristic endoscopic findings of non-Helicobacter pylori Helicobacter (NHPH) gastritis, including white marbled appearance and crack-like mucosa, have been reported. However, these findings can also manifest in H. pylori (HP)-infected gastritis. This study compared NHPH gastritis and mild atrophic HP gastritis to identify features that may enhance NHPH diagnosis. MATERIALS AND METHODS: A total of 2087 patients underwent upper gastrointestinal endoscopy and were histologically evaluated by multiple gastric mucosal biopsies according to the updated Sydney System (USS) at Shinshu University Hospital between 2005 and 2023. Among them, nine patients were classified into the NHPH group and 134 patients with HP infection and mild atrophy were classified into the HP group for retrospective comparisons of endoscopic findings and clinicopathological characteristics. RESULTS: All nine patients in the NHPH group (eight males [89%], median ± standard deviation [SD] age: 49 ± 13.0 years) were infected with H. suis. The 134 patients in the HP group contained 70 men (52%) and had a median ± SD age of 35 ± 19.9 years. Endoscopic findings were statistically comparable for white marbled appearance (three patients [33%] in the NHPH group and 37 patients [31%] in the HP group) and crack-like mucosa (three patients [33%] and 27 patients [20%], respectively). Diffuse redness was significantly less frequent in the NHPH group (one patient [14%] vs. 97 patients [72%], p < 0.001). White marbled appearance or crack-like mucosa without diffuse redness was significantly more common in the NHPH group (56% vs. 13%, p = 0.004), with a sensitivity and specificity of 56% and 87%, respectively. Mean USS neutrophil infiltration and Helicobacter density scores were significantly higher in the HP group (both p < 0.01), which might have influenced the endoscopic findings of diffuse redness. CONCLUSIONS: When endoscopic findings of white marbled appearance or cracked-like mucosa are present, evaluation for diffuse redness may contribute to a more accurate diagnosis of NHPH gastritis.

Separation of the diastereomers of phosphorothioated siRNAs by anion-exchange chromatography under non-denaturing conditions.

In recent years, several small interfering RNA (siRNA) therapeutics have been approved, and most of them are phosphorothioate (PS)-modified for improving nuclease resistance. This chemical modification induces chirality in the phosphorus atom, leading to the formation of diastereomers. Recent studies have revealed that Sp and Rp configurations of PS modifications of siRNAs have different biological properties, such as nuclease resistance and RNA-induced silencing complex (RISC) loading. These results highlight the importance of determining diastereomeric distribution in quality control. Although various analytical approaches have been used to separate diastereomers (mainly single-stranded oligonucleotides), it becomes more difficult to separate all of them as the number of PS modifications increases. Despite siRNA exhibits efficacy in the double-stranded form, few reports have examined the separation of diastereomers in the double-stranded form. In this study, we investigated the applicability of non-denaturing anion-exchange chromatography (AEX) for the separation of PS-modified siRNA diastereomers. Separation of the four isomers of the two PS bonds tended to improve in the double-stranded form compared to the single-stranded form. In addition, the effects of the analytical conditions and PS-modified position on the separation were evaluated. Moreover, the elution order of the Sp and Rp configurations was confirmed, and the steric difference between them, i.e., the direction of the anionic sulfur atom, appeared to be important for the separation mechanism in non-denaturing AEX. Consequently, all 16 peak tops of the four PS modifications were detected in one sequence, and approximately 30 peak tops were detected out of 64 isomers of six PS bonds, indicating that non-denaturing AEX is a useful technique for the quality control of PS-modified siRNA therapeutics.

First Detection of Chimeric ß-Lactamase CTX-M-64-Producing Salmonella Typhimurium from a Domestic Source in Japan.

Salmonella enterica subsp. enterica serovar Typhimurium has recently emerged worldwide as a producer of extended-spectrum ß-lactamase (ESBL). However, drug-resistant clinical isolates are rare in Japan. The common types of ESBLs found are the CTX-M-type ß-lactamases, including novel ß-lactamases such as CTX-M-64. CTX-M-64 has a chimeric structure comprising a combination of the CTX-M-1 and CTX-M-9 groups. In 2017, S. Typhimurium was isolated from stool, blood, and urine cultures of an 82-year-old man. Herein, we describe the discovery of a clinical isolate of S. Typhimurium in Japan. Antimicrobial susceptibility testing revealed that the isolate was resistant to third- and fourth-generation cephalosporins, including ceftazidime and monobactam. The minimum inhibitory concentrations of ceftazidime and ceftriaxone were restored by administration of clavulanic acid. Whole-genome sequencing analysis revealed that the isolate harbored the blaCTX-M-64 gene on an IncHI2/IncHI2A-type plasmid, with an assembly length of 174,477 bp. The genetic structure of the region surrounding the blaCTX-M-64 gene, ISKpn26-ΔISEcp1-blaCTX-M-64-orf477, was shared only with the chromosome sequence of S. Typhimurium detected in food-producing chickens in Guangdong, China. Although rare, S. Typhimurium can induce bloodstream infections and produce ESBL. To our knowledge, this is the first report of a CTX-M-64-producing Enterobacterales clinical isolate of domestic origin in Japan.

Probiotic Yeast from Miso Ameliorates Stress-Induced Visceral Hypersensitivity by Modulating the Gut Microbiota in a Rat Model of Irritable Bowel Syndrome.

Background/Aims: Recent studies indicate that probiotics, which have attracted attention as a treatment for irritable bowel syndrome, affect intestinal homeostasis. In this study, we investigated whether Zygosaccharomyces sapae (strain I-6), a probiotic yeast isolated from miso (a traditional Japanese fermented food), could improve irritable bowel syndrome symptoms. Methods: Male Wistar rats were exposed to water avoidance stress (WAS). The number of defecations during WAS and the visceral hypersensitivity before and after WAS were evaluated using colorectal distension. Tight junction changes were assessed by Western blotting. Some rats were fed with strain I-6 or ß-glucan from strain I-6. Changes in the intestinal microbiota were analyzed. The effect of fecal microbiota transplantation after WAS was evaluated similarly. Caco-2 cells were stimulated with interleukin-1ß and tight junction changes were investigated after coculture with strain I-6. Results: The increased number of stool pellets and visceral hypersensitivity induced by WAS were suppressed by administering strain I-6. The decrease in tight junction protein occludin by WAS was reversed by the administration of strain I-6. ß-Glucan from strain I-6 also suppressed those changes induced by WAS. In the rat intestinal microbiota, treatment with strain I-6 altered the ß-diversity and induced changes in bacterial occupancy. Upon fecal microbiota transplantation, some symptoms caused by WAS were ameliorated. Conclusions: These results suggest that traditional fermented foods such as miso in Japan are valuable sources of probiotic yeast candidates, which may be useful for preventing and treating stress-induced visceral hypersensitivity.

Visceral hypersensitivity induced by mild traumatic brain injury via the corticotropin-releasing hormone receptor: An animal model.

BACKGROUND: Mild blast-induced traumatic brain injury (bTBI) induces various gut symptoms resembling human irritable bowel syndrome (IBS) as one of mental and behavioral disorders. However, the underlying mechanisms remain unclear. We investigated whether the extremely localized brain impact extracranially induced by laser-induced shock wave (LISW) evoked IBS-like phenomenon including visceral hypersensitivity and intestinal hyperpermeability in rats. METHODS: The rats were subjected to LISW on the scalp to shock the entire brain. Visceral hypersensitivity was evaluated by the threshold pressure of abdominal withdrawal reflex (AWR) using a colorectal distension test. Permeability was evaluated by the concentration of penetrating FITC-dextran from intestine and the mRNA expression levels of tight junction family proteins. Involvement of corticotropin-releasing factor receptor (CRFR) 1 and 2 was examined by evaluating mRNA expression and modulating CRFR function with agonist, recombinant CRF (10 µg/kg), and antagonist, astressin (33 µg/kg). High-throughput sequencing of the gut microbiota was performed by MiSeqIII instrument and QIIME tool. KEY RESULTS: The thresholds of the AWR were significantly lowered after LISW. Permeability was increased in small intestine by LISW along with decreased expression of tight junction ZO-1. LISW significantly increased CRFR1 expression and decreased CRFR2 expression. Visceral hypersensitivity was significantly aggravated by CRFR agonist and suppressed by CRFR antagonist. The α- and ß-diversity of the fecal microbiota was altered after LISW. CONCLUSIONS AND INFERENCES: LISW provoked visceral hypersensitivity, small intestinal hyperpermeability, altered expression of CRFRs and changes in the microbiota, suggesting that genuine bTBI caused by LISW can induce a pathophysiology comparable to that of human IBS.

Transgenerational impacts of oral probiotic administration in pregnant mice on offspring gut immune cells and colitis susceptibility.

BACKGROUND AND AIM: The study of the impact of environmental factors during pregnancy on fetal development has so far been focused primarily on those negatively affecting human health; however, little is known about the effects of probiotic treatment during pregnancy on inflammatory bowel diseases (IBD). In this study, we investigated whether oral administration of heat-killed probiotics isolated from fermented foods decreased the vulnerability of offspring to IBD. METHODS: Probiotics were administered to the pregnant mice until the birth of pups, after which the parent mice were maintained with autoclaved water. Partial pups were evaluated for dextran sodium sulfate-induced colitis. The influence of CD11c+ CD103+ dendritic cells (DCs) and regulatory T cells (Tregs) in mesenteric lymph nodes of parent mice and their pups was analyzed. RESULTS: Oral administration of heat-killed probiotics to pregnant dams significantly decreased inflammation induced by dextran sodium sulfate in pups. Probiotic treatment increased the number of CD103+ DCs, and the expression of ß8-integrin in CD103+ DCs and Tregs in mesenteric lymph nodes, not only in dams themselves but also in their offspring. CONCLUSIONS: Oral administration of probiotics during gestation induced transgenerational immunomodulatory effects on the gut-associated immune system and resilience to experimental colitis in the offspring. Our results suggest that consumption of fermented foods during pregnancy can be effective in preventing inflammatory diseases such as IBD beyond generation.

Ameliorating Role of Hydrogen-Rich Water Against NSAID-Induced Enteropathy via Reduction of ROS and Production of Short-Chain Fatty Acids.

BACKGROUND: Nonsteroidal anti-inflammatory drug (NSAID)-induced enteropathy, the mechanism of which is involved in oxidative stress, can be lethal due to hemorrhage. Thus, we aimed to investigate the effect of hydrogen-rich water (HRW), in terms of oxidative stress, on intestinal mucosal damage as well as changes in the gut microbiome and the short-chain fatty acids (SCFAs) content in feces. METHODS: Hydrogen-rich water was orally administered for 5 days to investigate the effectiveness of indomethacin-induced enteropathy in mice. Small intestinal damage and luminal reactive oxygen species (ROS) were evaluated to investigate the ameliorating effects of hydrogen. Then, components of the gut microbiome were analyzed; fecal microbiota transplantation (FMT) was performed using the cecal contents obtained from mice drinking HRW. The cecal contents were analyzed for the SCFAs content. Finally, cells from the macrophage cell line RAW264 were co-cultured with the supernatants of cecal contents. RESULTS: Hydrogen-rich water significantly ameliorated IND-induced enteropathy histologically and reduced the expression of IND-induced inflammatory cytokines. Microscopic evaluation revealed that luminal ROS was significantly reduced and that HRW did not change the gut microbiota; however, FMT from HRW-treated animals ameliorated IND-induced enteropathy. The SCFA content in the cecal contents of HRW-treated animals was significantly higher than that in control animals. The supernatant had significantly increased interleukin-10 expression in RAW264 cells in vitro. CONCLUSION: Hydrogen-rich water ameliorated NSAID-induced enteropathy, not only via direct antioxidant effects but also via anti-inflammatory effects by increasing luminal SCFAs. These results suggest that hydrogen may have therapeutic potential in small intestinal inflammatory diseases.

Examination of Conditions for External Quality Control in Identification of Microorganisms using Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry.

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) was approved for medical use in 2011 and is currently used as a rapid, accurate and lowcost technique for bacterial identification. External quality control for medical analysis is monitored using tests of the Japanese Association of Medical Technologists and Prefectural Association of Clinical Laboratory Technologists and through user surveys of reagent and equipment manufacturers. However, external quality control of bacterial typing using MS is not performed. Therefore, we examined procedures for evaluating quality control of bacterial typing using an identification reliability index at 38 facilities.

Proinflammatory role of basophils in oxazolone-induced chronic intestinal inflammation.

BACKGROUND AND AIM: The functions of basophils have not been elucidated until recently because of their rarity. However, with recent developments in basophil-specific antibodies and basophil-deficient animals, the roles of basophils in various diseases related to chronic inflammation have been clarified. In this study, we aimed to investigate the roles of basophils in human ulcerative colitis (UC) and oxazolone (OXA) colitis using genetically engineered Mcpt8DTR mice. METHODS: Immunohistochemical staining of human colon specimens was performed to examine the involvement of basophils in the pathogenesis of UC. We examined the correlation between the number of infiltrating basophils and the UC endoscopic index of severity (UCEIS), Mayo score, and Matts score. We also examined the correlation between eosinophil count and basophil infiltration. In murine experiments, we examined whether basophil infiltration was involved in OXA-induced colitis and whether basophil depletion improved inflammation in Mcpt8DTR mice. RESULTS: Colonic basophil infiltration was significantly increased in patients with UC. There were significant correlations between UCEIS, Mayo score, Matts score, and the number of infiltrating basophils. In murine OXA-induced colitis, a significant increase in basophil infiltration was observed. When basophils were depleted by diphtheria toxin in Mcpt8DTR mice, inflammation improved significantly and mRNA expression of some proinflammatory cytokines, including Tnf-α and Ifn-γ decreased significantly. CONCLUSION: Basophil infiltration correlated with endoscopic, clinical, and pathological scores in human UC independently of eosinophil infiltration, and depletion of basophils ameliorated mucosal inflammation in murine OXA-induced colitis, collectively suggesting that basophils exert a proinflammatory role in chronic intestinal inflammation such as UC.

Immunoglobulin G4-related disease accompanying a small intestinal ulcer: A case.

Immunoglobulin (Ig)G4-related disease (IgG4-RD) is a systemic condition associated with fibroinflammatory lesions and is characterized by elevated serum IgG4 levels and IgG4-positive cell infiltration into the affected tissues. It has been reported that IgG4-RD affects a variety of organs but uncommonly affects the gastrointestinal tract. In particular, there are few cases of lesions in the small intestine, except for sclerosing mesenteritis, which were mostly diagnosed from surgical specimens. Herein, we describe the case of a 70-year-old man who initially presented with abdominal pain, headache, later cognitive decline, and gait disturbance caused by IgG4-RD. Colonoscopy revealed irregular ulcers in the terminal ileum, and computed tomography of the head showed hypertrophic pachymeningitis. Numerous IgG4-positive cells were detected in the ileal and dural biopsies. We diagnosed the patient with IgG4-RD and started steroid pulse therapy. After initiation of treatment, the symptoms quickly improved. The patient was discharged from the hospital after starting oral prednisolone treatment (30 mg). The dosage was gradually reduced to 10 mg. A follow-up colonoscopy revealed scarring of the ileal ulcers. This case may provide valuable information regarding the endoscopic findings of small intestinal lesions in IgG4-RD.

Protective Effect of Luminal Uric Acid Against Indomethacin-Induced Enteropathy: Role of Antioxidant Effect and Gut Microbiota.

BACKGROUND: Uric acid (UA) has anti- and pro-inflammatory properties. We previously revealed that elevated serum UA levels provide protection against murine small intestinal injury probably via luminal UA secreted in the small intestine. Luminal UA may act as an antioxidant, preventing microbiota vulnerability to oxidative stress. However, whether luminal UA is increased under hyperuricemia and plays a protective role in a dose-dependent manner as well as the mechanism by which luminal UA exerts its protective effects on enteropathy remains unknown. METHODS: Inosinic acid (IMP) (1000 mg/kg, i.p.) was administered to obtain high serum UA (HUA) and moderate serum UA (500 mg/kg IMP, i.p.) mice. UA concentrations and levels of oxidative stress markers in the serum and intestine were measured. Mice received indomethacin (20 mg/kg, i.p.) to evaluate the effects of UA on indomethacin-induced enteropathy. Reactive oxygen species (ROS) on the ileal mucosa were analyzed. The fecal microbiota of HUA mice was transplanted to investigate its effect on indomethacin-induced enteropathy. RESULTS: IMP increased luminal UA dose-dependently, with higher levels of luminal antioxidant markers. Indomethacin-induced enteropathy was significantly ameliorated in both UA-elevated groups, with decreased indomethacin-induced luminal ROS. The microbiota of HUA mice showed a significant increase in α-diversity and a significant difference in ß-diversity from the control. Fecal microbiota transplantation from HUA mice ameliorated indomethacin-induced enteropathy. CONCLUSIONS: The protective role of luminal UA in intestinal injury is likely exerted via oxidative stress elimination and microbiota composition modulation, preferably for gut immunity. Therefore, enhancing anaerobic conditions using antioxidants is a potential therapeutic target.

Changes in Colonic Inflammation Related with Takayasu Arteritis during a 10-year Observation Period.

Takayasu arteritis (TA) sometimes presents with colitis, which may be diagnosed as inflammatory bowel disease unclassified (IBDU) because of atypical or mixed findings of ulcerative colitis (UC) and Crohn's disease. We herein report an 18-year-old girl presenting with colitis with an occasional high fever eventually diagnosed as TA with IBDU. Colonic inflammation was initially discontinuous and stronger in the proximal colon, atypical of UC. However, over 10-year observation, the distribution of colonic inflammation varied and became UC-like. Variations in TA-related colonic inflammations over time have been unclear. Our long-term observation might help clarify the details of TA-related colonic inflammation.

Antibiotic resistance and the presence of bla CfxA and bla CSP genes in ß-lactamase-producing clinical Capnocytophaga isolates from a university hospital in Japan.

Introduction . Capnocytophaga species are common inhabitants of the oral cavity and can be responsible for systemic diseases in immunocompromised patients with granulocytopenia. Furthermore, it has been reported that some clinical isolates of Capnocytophaga species produce extended-spectrum ß-lactamases (ESBLs).Gap statement. Information is lacking about the types of ß-lactamase genes possessed by Capnocytophaga spp. and the antimicrobial susceptibility of Capnocytophaga spp. possessing each ß-lactamase gene.Aim. The aim of this study was to investigate the presence of ß-lactamase genes in clinical strains of ß-lactamase-producing Capnocytophaga species isolated from clinical samples acquired at Shinshu University Hospital and examine the antimicrobial susceptibility of those strains.Methodology. The ß-lactamase-producing Capnocytophaga species (n=49) were obtained from clinical specimens. PCR assays were used to detect bla CfxA, bla CSP, bla TEM, bla CepA/CblA and transposon Tn4555 genes. Southern hybridization assays were used to detect bla CfxA and bla CSP. The minimum inhibitory concentration of some ß-lactams was determined using the E-test method.Results. PCR analysis indicated that the bla CfxA gene was present in 15 (30.6 %) and the bla CSP gene in 35 (69.3 %) of the 49 Capnocytophaga strains investigated, . Both bla CfxA and bla CSP genes were detected in a Capnocytophaga gingivalis strain. The PCR results were confirmed by Southern hybridization assays. Transposon Tn4555 was only detected in Capnocytophaga spp. harbouring the bla CfxA gene. All the ß-lactamase-producing Capnocytophaga isolates were susceptible to ceftazidime-clavulanic acid, cefoxitin and imipenem. In contrast, most of the isolates were resistant to amoxicillin.Conclusions. The clinical isolates of Capnocytophaga spp. showed a high prevalence of the bla CSP gene in Japan. The presence of the bla CSP gene was distributed in Capnocytophaga sputigena as well as other Capnocytophaga spp. These results seem to suggest the dissemination of bla CfxA and bla CSP ß-lactamase genes among Capnocytophaga species.