Yasuyuki Sugasawa

Bio: Yasuyuki Sugasawa is an academic researcher from Toho University. The author has contributed to research in topics: Univariate analysis & Nalidixic acid. The author has an hindex of 3, co-authored 6 publications receiving 85 citations.

Role of infected grandmothers in transmission of Helicobacter pylori to children in a Japanese rural town.

Abstract: Aim Although the prevalence of Helicobacter pylori (H. pylori) increases with age and the main period of acquisition is childhood, the route of transmission of H. pylori infection remains unclear. This study aims to evaluate the relationship between prevalence of children and grandparents. Methods A total of 838 consecutive children who attended the Urita clinic and whose blood was taken for work up were enrolled in the present study. They were 449 boys and 389 girls, with a mean age of 12.4 years. H. pylori serology of their family members who were living together in one house was picked up to analyse intra-familial clustering of H. pylori infection. The family members of these children consisted of 448 fathers, 597 mothers, 205 grandfathers, 361 grandmothers and 589 siblings. Results The seropositive rates of mothers, grandmother and siblings in seropositive children were significantly higher than those in seronegative children. H. pylori infection in mothers and grandmothers was a marked risk factor for infection in the index children. Larger family size was not a risk factor for H. pylori infection. In contrast, having an infected father or grandfather was not an independent predictor for children infection. Conclusions Our data demonstrate that not only mother-to-child transmission but also grandmother-to-child transmission is an important mechanism for the spread of H. pylori in a three-generation household.

Molecular Characterization of Extraintestinal Escherichia coli Isolates in Japan: Relationship between Sequence Types and Mutation Patterns of Quinolone Resistance-Determining Regions Analyzed by Pyrosequencing

Abstract: Infection from fluoroquinolone-resistant Enterobacteriaceae is an increasing health problem worldwide. In the present study, we developed a pyrosequencing-based high-throughput method for analyzing the nucleotide sequence of the quinolone resistance-determining regions (QRDRs) of gyrA and parC. By using this method, we successfully determined the QRDR sequences of 139 out of 140 clinical Escherichia coli isolates, 28% of which were nonsusceptible to ciprofloxacin. Sequence results obtained by the pyrosequencing method were in complete agreement with those obtained by the Sanger method. All fluoroquinolone-resistant isolates (n = 35; 25%) contained mutations leading to three or four amino acid substitutions in the QRDRs. In contrast, all isolates lacking a mutation in the QRDR (n = 81; 57%) were susceptible to ciprofloxacin, levofloxacin, and nalidixic acid. The qnr determinants, namely, the qnrA, qnrB, and qnrS genes, were not detected in the isolates, and the aac(6')-Ib-cr gene was detected in 2 (1.4%) of the isolates. Multilocus sequence typing of 34 randomly selected isolates revealed that sequence type 131 (ST131) (n = 7; 20%) is the most prevalent lineage and is significantly resistant to quinolones (P < 0.01). The genetic background of quinolone-susceptible isolates seemed more diverse, and interestingly, neighboring STs of ST131 in the phylogenetic tree were all susceptible to ciprofloxacin. In conclusion, our investigation reveals the relationship between fluoroquinolone resistance caused by mutations of QRDRs and the population structure of clinical extraintestinal E. coli isolates. This high-throughput method for analyzing QRDR mutations by pyrosequencing is a powerful tool for epidemiological studies of fluoroquinolone resistance in bacteria.

Prognostic significance of the serum phosphorus level and its relationship with other prognostic factors in multiple myeloma.

Abstract: We studied the serum phosphorus (P) level of 110 patients with multiple myeloma (MM) (age range 42-83 years, median 62 years) and evaluated the relationship between that and other prognostic factors. Serum P level significantly correlated with the prognostic factors that are relevant to renal dysfunction: serum creatinine (P 3.8 mg/dl). The survival time was significantly shorter in these patients (P=0.000087). Multivariate analysis (Cox's proportional hazards regression model) showed that the serum P level is a significant negative prognostic factor in MM patients.

Prognostic factors in elderly multiple myeloma patients aged 65 years or older: Comparison with nonelderly patients with multiple myeloma

Abstract: Background: Although age is a prognostic factor in multiple myeloma (MM), the prognostic factors in elderly MM patients may be different to those in nonelderly MM patients due to the patient's age. The difference in the significance of prognostic factors between elderly MM patients and the nonelderly MM patients was studied. Methods: Forty-two elderly MM patients aged 65 years or older were compared with 68 nonelderly MM patients, who were less than 65 years of age. The characteristics of the elderly patients included: aged 65–81 years (median, 72 years); female/male ratio of 22 : 20; 24 IgG type cases, 13 IgA type cases, one non-secretory case and four cases of Bence-Jones type; one case of stage I, 12 cases at stage II and 29 cases at stage III. The prognostic factors were evaluated by means of univariate analysis and Cox's multivariate analysis. Results: The median survival time was significantly shorter in the elderly MM patients (24 months) than in the nonelderly patients (50 months) (P < 0.01). Of the univariate prognostic factors, corrected serum Ca (cCa), hemoglobin, serum P, bone marrow plasma cell and uric acid were significant prognostic factors in the elderly MM patients, while nine factors including those listed here, were significant in nonelderly controls. Multivariate analysis showed that serum cCa was the only independent prognostic factor (P = 0.019) in elderly MM patients, while serum P and bone lesions were significant prognostic factors in nonelderly MM patients. Conclusion: Corrected serum c. (cCa) was an independent prognostic factor in elderly MM patients.

Epidemiology ofHelicobacter pyloriInfection

Abstract: Medline and PubMed databases were searched on epidemiology of Helicobacter pylori for the period of April 2013–March 2014. Several studies have shown that the prevalence of H. pylori is still high in most countries. In north European and North American populations, about one‐third of adults are still infected, whereas in south and east Europe, South America, and Asia, the prevalence of H. pylori is often higher than 50%. H. pylori remains highly prevalent in immigrants coming from countries with high prevalence of H. pylori. However, the lower prevalence of infection in the younger generations suggests a further decline of H. pylori prevalence in the coming decades. Low socioeconomic conditions in childhood are confirmed to be the most important risk factors for H. pylori infection. Although the way the infection is transmitted is still unclear, interpersonal transmission appears to be the main route. Finally, H. pylori recurrence after successful eradication can still occur, but seems to be an infrequent event.

Global Extraintestinal Pathogenic Escherichia coli (ExPEC) Lineages.

Abstract: SUMMARY Extraintestinal pathogenic Escherichia coli (ExPEC) strains are responsible for a majority of human extraintestinal infections globally, resulting in enormous direct medical and social costs. ExPEC strains are comprised of many lineages, but only a subset is responsible for the vast majority of infections. Few systematic surveillance systems exist for ExPEC. To address this gap, we systematically reviewed and meta-analyzed 217 studies (1995 to 2018) that performed multilocus sequence typing or whole-genome sequencing to genotype E. coli recovered from extraintestinal infections or the gut. Twenty major ExPEC sequence types (STs) accounted for 85% of E. coli isolates from the included studies. ST131 was the most common ST from 2000 onwards, covering all geographic regions. Antimicrobial resistance-based isolate study inclusion criteria likely led to an overestimation and underestimation of some lineages. European and North American studies showed similar distributions of ExPEC STs, but Asian and African studies diverged. Epidemiology and population dynamics of ExPEC are complex; summary proportion for some STs varied over time (e.g., ST95), while other STs were constant (e.g., ST10). Persistence, adaptation, and predominance in the intestinal reservoir may drive ExPEC success. Systematic, unbiased tracking of predominant ExPEC lineages will direct research toward better treatment and prevention strategies for extraintestinal infections.

Pathogenesis and clinical management of Helicobacter pylori gastric infection.

Abstract: Helicobacter pylori (H. pylori) is a gram-negative bacterium that infects approximately 4.4 billion individuals worldwide. However, its prevalence varies among different geographic areas, and is influenced by several factors. The infection can be acquired by means of oral-oral or fecal-oral transmission, and the pathogen possesses various mechanisms that improve its capacity of mobility, adherence and manipulation of the gastric microenvironment, making possible the colonization of an organ with a highly acidic lumen. In addition, H. pylori presents a large variety of virulence factors that improve its pathogenicity, of which we highlight cytotoxin associated antigen A, vacuolating cytotoxin, duodenal ulcer promoting gene A protein, outer inflammatory protein and gamma-glutamyl transpeptidase. The host immune system, mainly by means of a Th1-polarized response, also plays a crucial role in the infection course. Although most H. pylori-positive individuals remain asymptomatic, the infection predisposes the development of various clinical conditions as peptic ulcers, gastric adenocarcinomas and mucosa-associated lymphoid tissue lymphomas. Invasive and non-invasive diagnostic methods, each of them with their related advantages and limitations, have been applied in H. pylori detection. Moreover, bacterial resistance to antimicrobial therapy is a major challenge in the treatment of this infection, and new therapy alternatives are being tested to improve H. pylori eradication. Last but not least, the development of effective vaccines against H. pylori infection have been the aim of several research studies.

Diagnosis and epidemiology of Helicobacter pylori infection.

Abstract: A limited amount of new information was published in the field of diagnosis and epidemiology of Helicobacter pylori this last year. Besides some improvement in current tests, it is interesting to note the attempts to identify severe disease, for example gastric cancer, by breath analysis using nanomaterial-based sensors. In contrast, the predictive value for gastric cancer and atrophy of pepsinogen determinations was found inadequate. Prevalence studies of H. pylori infection have been carried out in adults and children around the world in the general population but also in specific communities. The usual risk factors were found. In addition, a Japanese study highlighted the role of grandmothers in the familial transmission of H. pylori. A study showed that the infection may not always readily establish itself in children, given the number of transient infections observed. It was also noted that after eradication, a first-year relapse is likely to be a recurrence of the previous infection, while later on it is probably a reinfection with a new strain.

Virulence Factors of Helicobacter pylori: A Review

Abstract: Helicobacter pylori is a spiral-shaped Gram-negative bacterium that colonizes the human stomach and can establish a long-term infection of the gastric mucosa, a condition that affects the relative risk of developing various clinical disorders of the upper gastrointestinal tract, such as chronic gastritis, peptic ulcer disease, mucosa-associated lymphoid tissue (MALT) lymphoma, and gastric adenocarcinoma. H. pylori presents a high-level of genetic diversity, which can be an important factor in its adaptation to the host stomach and also for the clinical outcome of infection. There are important H. pylori virulence factors that, along with host characteristics and the external environment, have been associated with the different occurrences of diseases. This review is aimed to analyzing and summarizing the main of them and possible associations with the clinical outcome.