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Background: Asymptomatic carriers of methicillin‐resistant Staphylococcus aureus (MRSA) are important sources of nosocomial transmission. However, the route of transmission of MRSA is not completely understood. The purpose of this study was to calculate MRSA transmission rates in a hospital with a high MRSA infection/colonization density and inadequate hand hygiene compliance. Methods: The prevalence of MRSA colonization among 157 patients at the time of admission to and discharge from a medical school hospital in Japan was determined by performing surveillance cultures. All MRSA isolates were evaluated using multilocus sequence typing (MLST) to identify the transmission routes. Results: Methicillin‐resistant S. aureus was prevalent in 1.9% of our study population. MRSA was acquired during hospitalization at a rate of 4.0/1000 patient‐days. At discharge, 5.1% of the patients exhibited MRSA colonization; this was significantly higher than the prevalence noted upon admission (P < 0.001). MLST documented three possible nosocomial transmission events. MRSA colonization was detected using surveillance cultures prior to being identified by conventional, clinically oriented examinations. Conclusions: Multilocus sequence typing results suggested that patients who were colonized with MRSA acquired it during hospitalization. These results reinforce the importance of infection control for preventing nosocomial MRSA transmission in hospitalized patients. Methicillin‐resistant Staphylococcus aureus (MRSA) was acquired during the hospitalization at an incidence rate of 4.0/1000 patient‐days. Increasing the frequency of microbiological diagnosis could help reduce MRSA transmission. [ABSTRACT FROM AUTHOR]

Background: The aim of the present study was to evaluate the clinical utility of transthoracic echocardiography (TTE) for screening abdominal aortic aneurysm (AAA) and to identify important TTE indices associated with AAA in a Japanese population.Methods: We prospectively studied 1912 patients who were referred for TTE. AAA was defined as ≥ 30 mm in size.Results: The abdominal aorta was visualized in 95.1% (1818/1912) by TTE. AAA was identified in 2.6% (47/1818). The aortic root size was significantly larger in patients with AAA than those without (36.0 ± 4.1 vs. 31.7 ± 4.2 mm, p < 0.001). The aortic root size had a fair correlation with abdominal aortic size (r = 0.31, p < 0.001). The aortic root size of ≥ 34 mm was predictive of AAA by receiver operating characteristic curve analysis (area under the curve = 0.78, p < 0.001). Multiple logistic regression analysis revealed that aortic root size (Hazard ratio 1.23, p < 0.001) and age (Hazard ratio 1.05, p = 0.013) were the independent predictors of AAA.Conclusions: The feasibility of the abdominal aortic visualization during TTE was excellent. The aortic root size measured by TTE was the independent predictor of AAA. Screening for AAA during TTE appeared to be useful especially in the older patients with a large (≥34 mm) aortic root. [ABSTRACT FROM AUTHOR]

In IL-5 transgenic mice (C3H/HeN-TgN(IL-5)-Imeg), in which 50% of peripheral blood leukocytes are eosinophils, the development of infection by Leishmania amazonensis was clearly suppressed. To determine mechanistically how this protozoan parasite is killed, we performed in vitro killing experiments. Either IL-4 or IFN-γ effectively stimulated eosinophils to kill Leishmania amazonensis promastigotes, and most of the killing was inhibited by catalase but not by the NO inhibitor L-N5-(1-iminoethyl)-ornithine, suggesting that hydrogen peroxide is responsible for the killing of L. amazonensis by eosinophils. There was no significant degranulation of eosinophils in the culture, because eosinophil peroxidase was not detected in culture supernatants when L. amazonensis promastigotes were killed by activated eosinophils. Such resistance was also observed in BALB/c mice, which are highly susceptible to L. amazonensis. Expression plasmids for IL-4, IL-5, and IFN-γ were transferred into muscle by electroporation in vivo starting 1 week before infection. Expression plasmid for IL-5 was most effective in slowing the development of infection among three expression plasmids. Expression plasmid for IL-4 was slightly effective and that for IFN-γ had no effect on the progress of disease. These results suggest that IL-5 gene transfer into muscle by electroporation is useful as a supplementary protection method against L. amazonensis infection. [ABSTRACT FROM AUTHOR]

Background: Asymptomatic carriers of methicillin-resistant Staphylococcus aureus (MRSA) are important sources of nosocomial transmission. However, the route of transmission of MRSA is not completely understood. The purpose of this study was to calculate MRSA transmission rates in a hospital with a high MRSA infection/colonization density and inadequate hand hygiene compliance., Methods: The prevalence of MRSA colonization among 157 patients at the time of admission to and discharge from a medical school hospital in Japan was determined by performing surveillance cultures. All MRSA isolates were evaluated using multilocus sequence typing (MLST) to identify the transmission routes., Results: Methicillin-resistant S. aureus was prevalent in 1.9% of our study population. MRSA was acquired during hospitalization at a rate of 4.0/1000 patient-days. At discharge, 5.1% of the patients exhibited MRSA colonization; this was significantly higher than the prevalence noted upon admission ( P  < 0.001). MLST documented three possible nosocomial transmission events. MRSA colonization was detected using surveillance cultures prior to being identified by conventional, clinically oriented examinations., Conclusions: Multilocus sequence typing results suggested that patients who were colonized with MRSA acquired it during hospitalization. These results reinforce the importance of infection control for preventing nosocomial MRSA transmission in hospitalized patients.

Background: To implement effective precautions to avoid methicillin-resistant Staphylococcus aureus (MRSA) nosocomial infections, it is important to clarify when, how, and from whom MRSA was transmitted to the patients. However, MRSA strains obtained from outpatient population were not analyzed, and the transmission routes of MRSA in the community are not completely understood. The purpose of this study was to clarify whether MRSA is spreading in community settings or whether MRSA transmission still occurs only in healthcare institutions., Methods: Surveillance cultures of 1274 residents living in a community were performed in two different areas, Kochi and Osaka prefectures of Japan. All isolated MRSA strains were evaluated using multilocus sequence typing (MLST) to clarify the transmission routes of MRSA. The results were compared with those of inpatients. Moreover, written questionnaires and medical records were analyzed., Results: Analysis of surveillance cultures from residents living in the community in Japan revealed an MRSA colonization rate of 0.94%. The proportion of MRSA to  S. aureus colonization was 2.6% in the 310 residents, which was significantly lower than in the 393 hospitalized patients (63.1%; P  < .0001). MRSA strains in residents are different from the endemic strains in the hospitalized patients. Previous hospital admission is a risk factor for MRSA infection of the endemic strain in hospital., Conclusions: Methicillin-resistant Staphylococcus aureus colonization in community setting is rare in Japan. MLST results suggest that some MRSA strains are moving to the community through previous hospital admissions; however, MRSA is not spreading in community settings.

The bacterial pathogen Helicobacter pylori (H. pylori) colonizes in over half of the world's population. H. pylori that establishes life-long infection in the stomach is definitely associated with gastro-duodenal diseases and a wide variety of non-gastrointestinal tract conditions such as immune thrombocytopenia. Triple therapy which consists of a proton pump inhibitor and combinations of two antibiotics (amoxicillin, clarithromycin or amoxicillin, metronidazol) is commonly used for H. pylori eradication. Recently, the occurrence of drug-resistant H. pylori and the adverse effect of antibiotics have severely weakened eradication therapy. Generally antibiotics induce the disturbance of human gastrointestinal microflora. Furthermore, there are inappropriate cases of triple therapy such as allergy to antibiotics, severe complications (liver and/or kidney dysfunction), the aged and people who reject the triple therapy. These prompt us to seek alterative agents instead of antibiotics and to develop more effective and safe therapy with these agents. The combination of these agents actually may result in lower a dose of antibiotics. There are many reports world-wide that non-antibiotic substances from natural products potentially have an anti-H. pylori agent. We briefly review the constituents derived from nature that fight against H. pylori in the literature with our studies.

Helicobacter pylori (H. pylori) infection causes gastro-duodenal diseases and a wide variety of non gastrointestinal tract conditions, such as idiopathic thrombocytopenic purpura (ITP). Many reports have provided robust evidence for understanding the pathogenesis of H. pylori. However, its cell division process is little known. H. pylori exhibits marked genetic diversity to survive under various stress conditions, leading to the emergence of a variety of clones with novel characteristics. In this report, we briefly summarize our results. H. pylori urease is essential to live in a low-pH environment. Bacterial motility and urea taxisis are also important features for persistent infection. The urease is controlled in response to the pH via post translational regulation. Genetic rearrangement occurs during persistent infection of an individual's stomach, which results in the appearance of a variety of new strains with novel characteristics. The cdrA (cell division-related gene A)--dysfunctional strain had acquired such novel characteristics: increased viability, long-term survival, and tolerance to antibiotics. Furthermore, colonization by a cdrA-dysfunctional strain results in decreased IL-8 production and, hence, attenuates the host's immunity to cause persistent infection. Among the factors involved in the bacterium-host interaction and pathogenesis, we describe the H. pylori CagA, BabA, SabA, and SOD. We discovered two H. pylori phages, including a new type of spherical phage, which cannot be classified into any existing virus category. The phages probably contribute to the evolution and pathogenesis of H. pylori. Eradication therapy covered by health insurance was approved for H. pylori-associated ITP. We reported an extra mechanism, the immunocomplex model (platelets, bacterial molecules, and anti H. pylori antibodies), in the development of H. pylori associated ITP. On the other hand, increased cases of unsuccessful eradication therapy are due to the increased occurrence of drug-resistant H. pylori. Non-antibiotic substances with anti-H. pylori activity are attracting much attention.

Aim: To investigate genetic diversity of Helicobacter pylori (H. pylori) cell division-related gene A (cdrA) and its effect on the host response., Methods: Inactivation of H. pylori cdrA, which is involved in cell division and morphological elongation, has a role in chronic persistent infections. Genetic property of H. pylori cdrA was evaluated using polymerase chain reaction and sequencing in 128 (77 American and 51 Japanese) clinical isolates obtained from 48 and 51 patients, respectively. Enzyme-linked immunosorbent assay was performed to measure interleukin-8 (IL-8) secretion with gastric biopsy specimens obtained from American patients colonized with cdrA-positive or -negative strains and AGS cells co-cultured with wild-type HPK5 (cdrA-positive) or its derivative HPKT510 (cdrA-disruptant). Furthermore, the cytotoxin-associated gene A (cagA) status (translocation and phosphorylation) and kinetics of transcription factors [nuclear factor-kappa B (NF-κB) and inhibition kappa B] were investigated in AGS cells co-cultured with HPK5, HPKT510 and its derivative HPK5CA (cagA-disruptant) by western blotting analysis with immunoprecipitation., Results: Genetic diversity of the H. pylori cdrA gene demonstrated that the cdrA status segregated into two categories including four allele types, cdrA-positive (allele types;Iand II) and cdrA-negative (allele types; III and IV) categories, respectively. Almost all Japanese isolates were cdrA-positive (I: 7.8% and II: 90.2%), whereas 16.9% of American isolates were cdrA-positive (II) and 83.1% were cdrA-negative (III: 37.7% and IV: 45.5%), indicating extended diversity of cdrA in individual American isolates. Comparison of each isolate from different regions (antrum and corpus) in the stomach of 29 Americans revealed that cdrA status was identical in both isolates from different regions in 17 cases. However, 12 cases had a different cdrA allele and 6 of them exhibited a different cdrA category between two regions in the stomach. Furthermore, in 5 of the 6 cases possessing a different cdrA category, cdrA-negative isolate existed in the corpus, suggesting that cdrA-negative strain is more adaptable to colonization in the corpus. IL-8 secretions from AGS revealed that IL-8 levels induced by a cdrA-disrupted HPKT510 was significantly lower (P < 0.01) compared to wild-type HPK5: corresponding to 50%-60% of those of wild-type HPK5. These data coincided with in vivo data that an average value of IL-8 in biopsy specimens from cdrA-positive and cdrA-negative groups was 215.6 and 135.9 pg/mL, respectively. Western blotting analysis documented that HPKT510 had no effect on CagA translocation and phosphorylation, however, nuclear accumulation of NF-κB was lower by HPKT510 compared to HPK5., Conclusion: Colonization by a cdrA-negative or cdrA-dysfunctional strain resulted in decreased IL-8 production and repression of NF-κB, and hence, attenuate the host immunity leading to persistent infection.

Identification of Diphyllobothrium species has been carried out based on their morphology, especially sexual organs. In addition to these criteria, PCR-based identification methods have been developed recently. A 20 year-old Japanese living in Kochi Prefecture passed tapeworm. He was successfully treated with single dose of gastrografin. We examined the morphologic features of the proglottids and eggs using histology and scanning electron microscope. We also analyzed mitochondrial cytochrome c oxidase subunit 1 (cox1) gene of the proglottids. The causative tapeworm species was identified as D. nihonkaiense based on the results of morphologic features and genetic analysis. We discussed the advantage of PCR-based identification methods of Diphyllobothrium species using cox1 sequence in the clinical laboratory.

Aim: To evaluate the prevalence of Helicobacter pylori (H. pylori) babA2, babB and a recombinant gene between babA2 and babB (babA2/B), and their role in the development of atrophic gastritis in Costa Rican and Japanese clinical isolates., Methods: A total of 95 continuous H. pylori-positive Costa Rican (41 males and 54 females; mean age, 50.65 years; SD, +/- 13.04 years) and 95 continuous H. pylori-positive Japanese (50 males and 45 females; mean age, 63.43; SD, +/- 13.21 years) patients underwent upper endoscopy from October 2005 to July 2006. They were enrolled for the polymerase chain reaction (PCR)-based genotyping of the H. pylori babA2, babB and babA2/B genes. Statistical analysis was performed using the chi(2) test and the Fisher's exact probability test and multivariate analysis was performed by logistic regression adjusting for gender and age. P < 0.05 was regarded as statistically significant., Results: The PCR-based genotyping of 95 Costa Rican and 95 Japanese isolates showed a higher prevalence of babA2 in Japan (96.8%) than in Costa Rica (73.7%), while that of babA2/B was higher in Costa Rica (11.6%) than in Japan (1.1%). In Costa Rican isolates only, babA2 was significantly associated with atrophic gastritis (P = 0.01)., Conclusion: These results suggest that the status of babA2 and babA2/B shows geographic differences, and that babA2 has clinical relevance in Costa Rica.

The cell division-related gene A (cdrA) of Helicobacter pylori is dispensable in vivo and unique in having a repressive role on cell division and long-term survival. To clarify its role, comparisons of the wildtype HPK5 and isogenic cdrA-disrupted mutant HPKT510 were examined by ultrastructural morphology, PBP profiles, and susceptibility to beta-lactam antibiotics during long-term cultivation. Ultrastructural analyses revealed that the shorter rods of HPKT510 had a slightly wider periplasmic space between the inner and the outer membrane than those of HPK5. Cell division of HPKT510 cells was complete even under high-salt conditions in which HPK5 cells became filamentous due to inhibition of division. The filamentous HPK5 cells constructed an inner membrane without a cell wall at the presumed division site. After 4 days of cultivation (the late stationary phase), most of the HPK5 cells turned into ghosts and aggregates, while some of the HPKT510 cells remained as curved rods, which coincided with the results of cell viability. HPKT510 cells became resistant to ampicillin killing compared to HPK5 cells, although their minimum inhibitory concentrations (MICs) and PBP profiles were not significantly different. These results suggest that the cdrA product represses cell division via inhibiting cell wall synthesis at division site. During infection in both mice and humans, inactivation of cdrA eventually gains biological aspects such as increased viability, long-term survival and tolerance to antibiotics and high-salt condition, which might enhance a persistent infection.

In IL-5 transgenic mice (C3H/HeN-TgN(IL-5)-Imeg), in which 50% of peripheral blood leukocytes are eosinophils, the development of infection by Leishmania amazonensis was clearly suppressed. To determine mechanistically how this protozoan parasite is killed, we performed in vitro killing experiments. Either IL-4 or IFN-gamma effectively stimulated eosinophils to kill Leishmania amazonensis promastigotes, and most of the killing was inhibited by catalase but not by the NO inhibitor L-N5-(1-iminoethyl)-ornithine, suggesting that hydrogen peroxide is responsible for the killing of L. amazonensis by eosinophils. There was no significant degranulation of eosinophils in the culture, because eosinophil peroxidase was not detected in culture supernatants when L. amazonensis promastigotes were killed by activated eosinophils. Such resistance was also observed in BALB/c mice, which are highly susceptible to L. amazonensis. Expression plasmids for IL-4, IL-5, and IFN-gamma were transferred into muscle by electroporation in vivo starting 1 week before infection. Expression plasmid for IL-5 was most effective in slowing the development of infection among three expression plasmids. Expression plasmid for IL-4 was slightly effective and that for IFN-gamma had no effect on the progress of disease. These results suggest that IL-5 gene transfer into muscle by electroporation is useful as a supplementary protection method against L. amazonensis infection.

To determine the incidence and clinical features of Giardia lamblia infection, we studied 1790 patients at Kochi Medical School Hospital from April 1998 to July 2001. Fecal samples were examined microscopically by the direct smear method, direct immunofluorescent assay and by Kohn's one-step staining for G. lamblia cysts. Cysts of G. lamblia were found in 17 of 1,790(0.95%) stool samples, indicating that G. lamblia infection is not rare in Kochi. The most characteristic feature was that G. lamblia-positive cases were more frequent in the advanced age group(41-79 years old) and most of the subjects (except 2 cases) with G. lamblia had no history of traveling overseas. Four subjects had symptoms related to G. lamblia infection. Thus, more attention should be given to parasitic infections in laboratory stool examinations in order to detect cyst carriers as potential sources of infection.