Enterohaemorrhagic Escherichia coli O121:H19 acquired an extended-spectrum ß-lactamase gene during the development of an outbreak in two nurseries.

Enterohaemorrhagic Escherichia coli (EHEC) is an important human pathogen worldwide. Although serotype O157 is currently the most dominant and important EHEC strain, serotypes O26, O111, O91, O103 and O121 are also recognized as serious pathogens that affect public health. EHEC outbreaks often occur in nurseries and elderly care facilities. In 2012, a nursery outbreak of EHEC O121 occurred during which the bacterium acquired a plasmid-borne extended-spectrum ß-lactamase (ESBL) gene. ESBL-producing E. coli O86 was concurrently isolated from one of the EHEC patients. Therefore, we investigated the isolates by whole-genome sequence (WGS) analysis to elucidate the transmission dynamics of the EHEC strains and the ESBL plasmid. According to WGS-based phylogeny, all 17 EHEC O121 isolates were clonal, while E. coli O86 was genetically distant from the EHEC O121 isolates. The complete sequence of an ESBL plasmid encoding the CTX-M-55 ß-lactamase was determined using S1-PFGE bands, and subsequent mapping of the WGS reads confirmed that the plasmid sequences from EHEC O121 and E. coli O86 were identical. Furthermore, conjugation experiments showed that the plasmid was capable of conjugative transfer. These results support the hypothesis that EHEC O121 acquired an ESBL-producing plasmid from E. coli O86 during the outbreak. This report demonstrates the importance of implementing preventive measures during EHEC outbreaks to control both secondary infection and the spread of antimicrobial resistance factors.

[Influence of Stx2 Subtype on Bacteriological Identification of Outbreaks of EHEC O157: H- Infections in Saitama City].

In 2013, two outbreaks of enterohemorrhagic Escherichia coli (EHEC) occurred in Saitama city. According to reports from each of the medical institutions that detected the EHEC isolates, the isolates seemed to differ in their production of Vero Toxin (VT / Shiga Toxin: Stx) since one isolate produced only Stx1 and the other produced both Stx1 and Stx2. However, a patient survey conducted by a public health center revealed that common foodstuffs had been consumed in both outbreaks. Because, the two EHEC isolates were newly detected from two people in one patient's family, we analyzed the phenotypic and genetic relationships among four isolates in total. All the isolates were serotyped as O157: H-, and both stx1 and stx2 were detected. Subsequently, all four isolates were shown to have the same pulsed-field gel electrophoresis (PFGE) banding pattern. The findings suggested that these isolates belonged to the same strain group. Among these cases, the isolates had stx2c which is one of the stx2 subtypes. Reportedly, some cases with the Stx2 subtype can not be detected using conventional tests for toxin. In addition, Stx2 can be overlooked as a result of this limitation of Stx-production tests. Both epidemiological research by public health centers and genetic analysis by prefectural and municipal public health institutes (PHIs) are very important for clarifying possible relationships among outbreaks, as in the present cases. Moreover, collaborations and networks among medical institutions, PHIs and public health centers should be further strengthened to prevent the spread of infections.

[Identification of resistance and susceptibility to cefotaxime in EHEC O121 strains isolated from an outbreak at two nurseries].

A Shiga toxin 2 producing enterohemorrhagic Escherichia coli (EHEC) O121: H19 was isolated from a 2-year-old child who attending a nursery. An EHEC O121 outbreak in two nurseries (A, B), involving a total of 17 infected persons including 12 children, was revealed through contact investigation. The symptoms of all infected persons were almost all mild, and no one developed the hemolytic uremic syndrome. The combination use of desoxycholate-hydrogen sulfide-lactose (DHL) and CHROMagar STEC as selective isolation media was employed for efficient fecal examination. Nursery A and nursery B were combined as one group after the outbreak in nursery A was confirmed. As a result, EHEC O121 infected persons were also detected in children from nursery B. The 17 strains of EHEC O121 obtained from the total population showed almost the same pulsed-gel electrophoresis (PFGE) pattern, suggesting that these strains were very closely related. However, 13 of these 17 strains obtained from nursery A were susceptible to cefotaxime, whereas the remaining 4 strains obtained from nursery B showed cefotaxime resistance. A cefotaxime resistant Escherichia coli (E. coli) O86 strain was isolated in the stool specimen from a child who had been infected with the cefotaxime resistant EHEC O121. Both the cefotaxime resistant EHEC O121 and E. coli O86 had the same drug resistant gene (bla(CTX-M-1) group). The child was the index case of these 4 later cases and had received no antibiotics therapy prior to the laboratory examination. These findings suggested the possibility that an EHEC O121 strain had acquired a drug resistant gene from E. coli O86 in the digestive tract of the child.

An outbreak of measles in Saitama City in 2007. What is the vaccination strategy to eliminate measles in Japan?

In the present study, to elucidate an outbreak of measles in Saitama City, Japan, we analyzed the data for all notified subjects with measles. According to an active surveillance program, a total of 464 subjects were notified in 2007. The clinical criteria for the diagnosis of measles were defined as at least 3 days of a generalized maculopapular rash; a fever of 38.0 degrees C or more; and cough, mucus, or pharyngitis. Two peaks according to age group were recognized: namely, children less than 2 years of age and adolescents from 15 to 19 years of age. The latter peak was associated with the period of time when the measles-mumps-rubella vaccine had become a social problem (40.9% of vaccinees and 41.6% of non-vaccinees in this group). Japan is said to be a developing country regarding its measles vaccination strategy. In addition, no national program against measles has yet been established. Continuous efforts to increase immunization coverage are needed to interrupt indigenous measles transmission. The Japanese Ministry of Health, Labor and Welfare should therefore plan and implement a nationwide program to eliminate measles in Japan.

[Genomic analysis of enterohemorrhagic Escherichia coli (EHEC) O157:H7 strains isolated in Saitama City].

To elucidate the origin of infection, we conducted epidemiological and bacteriological studies to clarify the origin of five sporadic outbreaks of enterohemorrhagic Escherichia coli (EHEC) O157:H7 between May and July 2007 in Saitama City and its outskirts. Of the 20 subjects were reported; including 6 patients and 5 infected persons, none of the 9 symptomatic subjects developed hemolytic-uremic syndrome. No association was confirmed between infection and food materials, but 11 organisms showed almost the same chromosomal DNA restriction patterns produced by pulsed-field gel electrophoresis. Our results suggested that these 5 sporadic outbreaks were part of a diffuse outbreak induced by an EHEC O157:H7 strain having a single origin.

Polymorphism of Trp64Arg in beta3-adrenergic receptor gene and serum LDL-cholesterol concentrations in healthy Japanese.

BACKGROUND: Polymorphism of Trp64Arg in the beta(3)-adrenergic receptor (beta(3)-AR) gene may play a critical role in lipid and lipoprotein metabolism by mediating lipolysis and thermogenesis. Since the frequency of Arg alleles of the beta(3)-AR gene is generally low among many populations, studies on the Arg/Arg genotype in relation to lipid and lipoprotein metabolism are required in countries such as Japan which has a relatively high frequency of the Arg allele. METHODS: We genotyped 275 clinically healthy Japanese (male/female, 134/141, mean 45.7 years) without medication for beta(3)-AR gene polymorphism by polymerase chain reaction-restriction fragment length polymorphism analysis, and investigated the effects of the gene polymorphism on clinical parameters including body mass index (BMI), blood pressure and serum lipid and lipoprotein concentrations. RESULTS: The genotype frequencies were: Trp/Trp, 68.0%; Try/Arg, 28.0% and Arg/Arg, 4.0%, with an allele frequency of 0.18 for Arg64. When subjects were divided into three groups according to the genotype, a significant increase of serum LDL-cholesterol (LDL-C) concentration in the Arg/Arg group (3.48 +/- 1.59 mmol/L) was observed when compared with those of the Trp/Trp and Arg/Trp groups (3.15 +/- 0.80, 3.25 +/- 0.92 mmol/L, respectively). Genotype differences did not show any significant effect on other parameters. Spearman's rank correlation demonstrated a significant relationship between LDL-C concentrations and the number of Arg alleles, age and BMI. Multiple regression analysis, using LDL-C concentration as a criterion variable and some factors including beta(3)-AR gene polymorphism as explanatory variables, revealed that the number of Arg alleles was a significant and independent factor for LDL-C concentrations, along with age and BMI. CONCLUSIONS: These findings suggested a role of the beta(3)-AR gene polymorphism in regulating lipid and lipoprotein metabolism, showing small but significant effects on elevated LDL-C values in subjects with Arg/Arg, but not Trp/Arg and Trp/Trp genotypes.

Retrospective cohort study of smoking and lung cancer incidence in rural prefecture, Japan.

OBJECTIVES: We conducted an epidemiological study of the relationship between lung cancer incidence and smoking, with special reference to the benefits of smoking cessation for reducing lung cancer incidence, to promote a local smoking control program. METHODS: The study was a retrospective cohort study. The population studied was 16,383 male examinees of lung cancer health examinations in 1995 in Tottori Prefecture, Japan. Smoking status from the questionnaire during the health examination was used as the exposure variable. Endpoint (lung cancer incidence) was obtained from the Tottori population-based cancer registry. A multivariable analysis using the Cox proportional hazard model was adapted for statistical analysis. The average follow-up period was 4.3 years. RESULTS: The hazard ratio of current smokers for the incidence of lung cancer was 4.9, whereas that of ex-smokers was 2.2. The dose-response relationship between lung cancer incidence and lifetime cigarette consumption (pack year) was determined. The ratio increased among younger subjects (under 65 years old). The hazard ratio of ex-smokers decreased with years just after quitting smoking, and reached the level of never smokers after 10-19 years from smoking cessation. CONCLUSIONS: We reconfirmed that the magnitude of risk estimates of smoking for lung cancer incidence was similar to those of previous studies, and smoking cessation was effective for reducing lung cancer risk.

[Prevalence of the homebound in the elderly population within a community determined by using three measurement scales].

OBJECTIVES: In this cross-sectional study, we examined the prevalence of the homebound among community-dwelling elderly people who were independent in daily living and similarity in the criteria of three measurement scales of homebound. METHODS: Of all residents aged 65 and older residing in Kishimoto town, Tottori Prefecture (n = 1,383), 1,316 (95.2%) who were living at home participated in a baseline survey in October 2001. All the subjects were independent in daily living. They were asked to fill out a questionnaire, which was delivered to them by a member of a public committee. We examined the prevalence of the homebound using three measurement scales (capability of leaving the house independently, frequency of going outdoors, and place of daily activities) with the chi-square test. RESULTS: The prevalences of the homebound were 4.2% for the capability of leaving the house independently, 26.8% for the frequency of going outdoors, and 8.4% for the place of daily activities. The significant factors for the homebound were age and gender. Differences in prevalence were noted by judging the three measurement scales. In typical farming villages, the prevalence of the homebound going outdoors less than once a week was higher than that in other areas. The criteria of the three measurement scales for the homebound were not similar (Cohen's Kappa = 0.13, 0.12, 0.27). CONCLUSIONS: We considered that using three measurement scales together in the study of the prevalence of the homebound is practical. The monitoring of the rate of mortality and disabilities associated with being homebound should be continued.

The lack of relationship between an endothelin-1 gene polymorphism (Ala288ser) and incidence of hypertension: a retrospective cohort study among Japanese workers.

BACKGROUND: Some case-control association studies revealed the relationship between some endothelin-1 (ET-1) gene polymorphisms and blood pressure. Because no report was available about the relationship between any ET-1 gene polymorphism and incidence of hypertension, we examined the relationship between novel ET-1 gene polymorphism (G862T / Ala288Ser in exon 5) and incidence of hypertension by a retrospective cohort study. METHODS: The subjects were Japanese workers at a company in Shimane Prefecture in Japan. The polymorphism with genome DNA extracted from the blood of the workers was analyzed using the polymerase chain reaction confronting two pair primers method. According to the results of two regular health checkups with a 6-year interval, the study population was divided into two groups by blood pressure and antihypertensive treatment in 1998, after excluding people who had hypertension in 1992. RESULTS: There were 133 (93 males and 40 females) incidences of hypertension observed among the study population of 922 (540 males and 382 females). In the univariate analysis, odds ratios of Ala/Ser and Ser/Ser against Ala/Ala were 0.98 (95% confidence interval [CI]): 0.7-1.4) and 0.79 (95% CI: 0.4-1.6), respectively. In the multivariate analysis adjusted for sex, age, body mass index, serum total cholesterol, fasting blood sugar, and smoking and drinking habits, odds ratios for Ala/Ser and Ser/Ser against Ala/Ala were 0.97 (95% CI: 0.7-1.4) and 0.75 (95% CI: 0.4-1.5), respectively. CONCLUSIONS: The ET-1 gene polymorphism in this study did not seem to be associated with the incidence of hypertension among the Japanese workers.

Change of the smoking behavior and related lifestyle variables among physicians in Fukuoka, Japan: a longitudinal study.

Two cross-sectional surveys of the entire membership of the Fukuoka Prefecture Medical Association were conducted in 1983 and 1990 using a self-administered questionnaire, and respondents were registered as the study cohort. In this investigation the trend of the actual prevalence of smoking among physicians and the relationship between their smoking cessation and living habits were studied. A decline in the actual prevalence of smoking was demonstrated among the 2,656 subjects who responded to both surveys (2,543 men and 113 women). To examine any relationship between lifestyle variables and smoking cessation after 1983, those who were smokers in 1983 (1,099 men and 7 women, total 1,106) were divided into two groups, according to whether or not they still smoked in 1990. Subjects who quit smoking accounted for a larger proportion of those physicians with any of the following life-style variables: earlier bedtimes, unawareness of mental stress, greater consumption of fresh vegetables and fruit, and less coffee consumption. Further observation of the relationship between smoking cessation and changes in lifestyle variables showed that there were more who quit smoking among those who became employed physicians, had an increase of the body mass index (BMI) and began to be aware of mental stress. These results suggested that, for physicians who smoked, it is a possibility that smoking was an important way of coping with stress, and thus pointed to the need to take mental-health measures to help physicians to stop smoking.

Smoking behavior and related lifestyle variables among physicians in Fukuoka, Japan: a cross sectional study.

A cross-sectional survey of the entire membership of the Fukuoka Prefecture Medical Association was conducted in 1983 using a self-administered questionnaire. In this investigation the actual prevalence of smoking among physicians and the relationship between their smoking habits and living habits were studied. The study subjects were divided into two groups: those who smoked (1,737 men and 17 women), and those who did not currently smoke (2,267 men and 169 women). It was realized that there were many who were currently non-smokers among women, subjects with a high body mass index, those with heart disease, those without peptic ulcers, those who underwent health check-ups regularly, those accustomed to an early bedtime, those who were not aware of mental stress, those who took regular exercise, those who consumed plenty of fresh vegetables, yellow and green vegetables and fruit, those who did not consume Japanese pickles, coffee.or green tea, and those who drank alcohol only occasionally and only in small amounts. The results of this study suggested the possibility that physicians who were smokers were a group who smoked little and could easily stop smoking. Moreover, non-smoking physicians were found to have a healthier lifestyle than those who smoked. It was considered that, in developing a smoking cessation program for physicians, it is important for them to establish more health-conscious lifestyles.

Possible role of 1-methylnicotinamide in the pathogenesis of Parkinson's disease.

This study tested the hypothesis, that nicotinamide N-methyltransferase (NAMT) activity in the brain could convert nicotinamide to 1-methylnicotinamide (MNA) and by that means damage the nigro-neostriatal dopaminergic neurons. The NAMT activities of rat brain and liver were assayed with gas chromatographic-mass spectrometric analysis in a selected ion monitoring system. They amounted to 0.30 nmol/mg x h and 0.51 nmol/mg x h, respectively. The MNA injection in rat substantia nigra pars compacta significantly decreased dopamine content in the striatum. NADH oxidation and lipid peroxidation by MNA via rat brain submitochondrial particles (SMP) under the condition of pH ranging from pH 6.0 to 10.0 were verified. The pH optimum for the NADH oxidation was 9.0. The pH optimum for the peroxidation of the lipid composing SMP by MNA was also 9.0. The lipid peroxidation in this assay was suppressed by superoxide dismutase. The superoxide anion formed by MNA via mitochondria might be involved in the etiology of Parkinson's disease.