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Biomedical subjects

Toshio Kishimoto

Publications and source records attributed to Toshio Kishimoto.

At least 19 recordsLinked to original sources

Outbreak of Chlamydia pneumoniae infection in a Japanese nursing home, 1999-2000.

OBJECTIVE: To identify risk factors for infection and severe illness due to Chlamydia pneumoniae. METHODS: To identify risk factors for infection, we conducted a case-control study among nursing home residents who had onset of symptoms during December 1, 1999, to February 20, 2000. To identify risk factors for severe illness among nursing home residents, we conducted a retrospective cohort study. SETTING: A nursing home providing long-term and day care services for elderly patients in Japan.Participants. Fifty-nine residents and 41 staff members of a nursing home. RESULTS: The attack rates for respiratory illness were 53% (31 of 59) among residents and 22% (9 of 41) among staff. Infection was confirmed in 15 resident and 2 staff case patients by isolation of C. pneumoniae from nasal swab specimens. Fifteen resident case patients developed severe illness (ie, bronchitis, pneumonia, and hypoxia); one case patient died. The median age of resident case patients was 87 years. We could identify neither the source of the outbreak nor significant risk factors for infection and severe illness in residents. However, residents with a higher level of physical activity were more likely to become infected, whereas older residents (aged more than 85 years) and those with a lower level of physical activity were more likely to develop severe illness (P>.05). Contact with residents was a risk factor for infection in staff (relative risk, undefined; P=.04). CONCLUSIONS: C. pneumoniae can cause large outbreaks of infection and severe illness among elderly persons, and its transmission is likely to be enhanced by close contacts among people in nursing homes. Therefore, early detection of an outbreak by means of better surveillance, and subsequent isolation of patients, may be effective control measures.

Aged↗

Prevalence of Chlamydophila pneumoniae among Bangladeshi children under age 5 years with acute respiratory infections.

Despite major improvements in the diagnosis of pathogenic organisms causing acute respiratory infections (ARIs), details of infections caused by atypical pathogens are not well understood, particularly in developing countries. This clinical and epidemiological research was conducted in Bangladesh to explore the prevalence of atypical pathogens in causing childhood pneumonia. Sixty-four children with ARI were studied at the Pediatric Outpatient Department of Dhaka Medical College Hospital, Bangladesh, during September through December 2000. In addition to clinical examination, hematological, radiological, and bacteriological examinations were performed. Antibody titers from paired sera against Mycoplasma pneumoniae and Legionella spp. in the acute and convalescent phases revealed that none of these children were infected with M. pneumoniae, while only one serum sample was positive for L. pneumophila serogroup 4. Antibody titers against Chlamydophila (Chlamydia) pneumoniae, determined by an indirect microimmunofluorescence method, and by an enzyme-linked immunosorbent assay (ELISA) kit (HITAZYME C. pneumoniae kit) indicated that 13 children (20.3%) were infected with C. pneumoniae. Our results indicate a high prevalence rate of C. pneumoniae, suggesting it is as an important causative pathogen of childhood pneumonia in Bangladesh.

Acute Disease↗

First detection of Rickettsia in soft-bodied ticks associated with seabirds, Japan.

Rickettsia was first detected in seabird soft-bodied ticks, Carios capensis and C. sawaii in Japan. According to sequence analysis, Rickettsia in Japan was identical to Rickettsia scc31 in C. capensis in the U.S.A. This suggested that an environmental circulation had consisted among microorganisms, ticks and long distance migratory seabirds around the Pacific Ocean.

Animals↗

The inhibitory effect of disodium cromoglycate on the growth of Chlamydophila (Chlamydia) pneumoniae in vitro.

Chlamydophila (Chlamydia) pneumoniae is associated with asthma and several other respiratory illnesses. Disodium cromoglycate (DSCG) is known to inhibit both immediate and late asthmatic responses. In this study, the inhibitory effect of DSCG on the growth of C. pneumoniae was examined by minimum inhibitory concentration (MIC) and pre-inoculation minimal cidal concentration (MCC) assays using HL cells and C. pneumoniae AR-39. DSCG below the clinically relevant concentration inhibited the growth of C. pneumoniae in a dose-dependent manner in both the MCC and MIC assays. The inhibitory effect was also time-dependent in the MCC assay at 20 mg/ml of DSCG. These results warrant further clinical study on the connection between C. pneumoniae infections and use of DSCG.

Cell Line↗

Seroprevalence of Coxiella burnetii infection in dairy cattle and non-symptomatic people for routine health screening in Korea.

We report results on the seroprevalence of antibodies to Coxiella burnetii in cattle and healthy people in Korea. Upon agreement with dairy owners, serum samples from 414 dairy cattle were collected between March and June 2001 and samples from 205 people for health screening were collected between April and December 2002. The sera were analyzed for the presence of anti-C. burnetii phase II antibodies using an indirect microimmunofluorescence test; strong fluorescence at a 1:32 dilution was regarded as positive. The overall seroprevalence of C. burnetii in cattle in Korea was 25.6%, with regional variation from 8.9 to 59.3%. Of the positive serum samples, 75.5% had antibody titers >or=1:256. By contrast, only 1.5% of people in a rural area were seropositive, and most of the positive samples had low antibody titers. In conclusion, this study showed that relatively high seropositivity of C. burnetii in dairy cattle, accordingly, the studies on the high-risk groups are needed to evaluate the seroprevalence for this organism in Korea.

Adult↗

Outbreak of respiratory tract infections on an islet in Korea: possible Chlamydia pneumoniae infection.

In March 2004, we experienced an outbreak of Chlamydia pneumoniae infection on an islet of Korea. In order to assess the significance of the epidemic, we performed a mass examination of 137 students (7-16 years old; male, 69; female, 58) at a school. The examination consisted of a questionnaire inquiring about respiratory symptoms, a serum antibody test for C. pneumoniae using a microimmunofluorescence (MIF) method and enzyme-linked immunosorbent assay (ELISA), and nasopharyngeal swab tests to detect of the organism by specific PCR and cell culture. The results demonstrated that 72 (58.3%) of the students had respiratory symptoms such as rhinorrhea, a sore throat, and/or cough or fever. The PCR positivity of acute-phase patients was 63% (12/19) and PCR positivity using the culture sample was 94% (18/19). However, the existence of the organism was not confirmed fluorescein isothiocyanate (FITC). ELISA, one of the serological methods utilized, demonstrated, in the same patients, 48% (13/27) positive IgM antibodies at the acute phase of the outbreak, and 16% (3/19) positive IgM antibodies during the convalescent phase. The index value (ID) 3.0 for single-sera IgG was 19% (5/27) and that for IgA was 4% (1/27) at the acute phase; the corresponding percentages in the convalescent phase were 11% (2/19) and 5% (1/19), respectively. However, as regards paired sera, no patient demonstrated a 1.35 ELISA ID value at 2 weeks, or an increased value of 1.0 at 8 weeks after the onset of the outbreak. In the MIF experiment, the percent positivity of unpaired IgM from the acute phase was 58% (11/19). At convalescent phase, this percentage was 47% (9/19); however, the positivity of paired serum IgG was 26% (5/19). In the same sample, the percentage of positive cases demonstrated by both ELISA and MIF approaches for single IgM was 37% (7/19) at the acute phase and 11% (2/19) at the convalescent phase. We were unable to isolate C. pneumoniae by cell culture, but we did obtain sufficient serological and PCR data to consider C. pneumoniae as the causative agent of the outbreak. Meaningful results were acquired in terms of serology, and were compared to the healthy population in Korea. Although it remains necessary to investigate the possibility of co-infection and to determine whether or not this outbreak coincides with the prevalence of influenza, it was unequivocally concluded that this outbreak of C. pneumoniae infection has occurred on an islet of Korea.

Adolescent↗

Acute Chlamydia pneumoniae infection with heat-shock-protein-60-related response in patients with acute coronary syndrome.

Recent evidence has suggested an association between Chlamydia pneumoniae infection and coronary atherosclerosis. A significant association has also been detected between heat shock protein (HSP) 60 antibody and the severity of coronary atherosclerosis. The aim of this study was to define the relationship between instability of ischemic heart disease (IHD) and serum levels of HSP60 and C. pneumoniae antibodies. Blood samples for the measurement of serum antibody titers were obtained from 1131 patients with ischemic heart disease (65+/-9 years; male/female, 828/303) and 127 non-IHD controls with normal coronary arteries (64+/-9 years; male/female, 60/67) on the day of cardiac catheterization. The serum levels of anti-human HSP60 IgG antibody and anti-chlamydial IgM, but not IgG or IgA, antibody were significantly higher in ACS patients than in stable IHD patients or controls. These results suggest that acute C. pneumoniae infection with HSP60-related immunological responses may contribute to the pathophysiology of acute coronary syndromes.

Acute Disease↗

Prevalence of antibodies against Simkania negevensis in a healthy Japanese population determined by the microimmunofluorescence test.

Simkania negevensis has been associated with bronchiolitis in infants and community-acquired pneumonia in adults. Reports of exposure to this microorganism are only available from Israel, North America and Western Europe. Currently, no standard method for diagnosis of S. negevensis infection has been established nor have prevalence rates been shown in Japan. For the first time we demonstrated the ability of the microimmunofluorescence (MIF) test to detect S. negevensis-specific immunoglobulin G and exposure to S. negevensis in Japan. The positive rate in healthy volunteers was 4.3% (25/588), with rates increasing with age. Results indicate the usefulness of the MIF test as a serological method for detecting S. negevensis-specific antibodies. A standard serological test for infection with S. negevensis is needed.

Adult↗

Chlamydia pneumoniae growth inhibition in human monocytic THP-1 cells and human epithelial HEp-2 cells by a novel phenoxazine derivative.

In this study the effects of 2-amino-phenoxazine-3-one (phenoxazine derivate, Phx-3) on Chlamydia (Chlamydophila) pneumoniae growth in human monocytic THP-1 cells as well as human epithelial HEp-2 cells were examined. Cells were infected with bacteria at an m.o.i. of 10 by centrifugation. After washing to remove any remaining bacteria, the cells were incubated with or without Phx-3 in the presence or absence of tryptophan for 72 h. The bacteria in cells were assessed by staining of chlamydial inclusions with FITC-labelled anti-chlamydial antibody, electron microscopic analysis, real-time RT-PCR specific for C. pneumoniae 16S rRNA and propagation on HEp-2 cells. Treatment with Phx-3 significantly inhibited growth of C. pneumoniae in THP-1 and HEp-2 cells. A decrease in the number of bacterial 16S rRNA transcripts was also confirmed in both cell lines by real-time RT-PCR. Electron microscopic studies revealed that treatment with Phx-3 induces bacterial destruction in most of the inclusion bodies in these cells. Addition of tryptophan to the culture slightly blocked the growth inhibition of C. pneumoniae by Phx-3. The reagents did not show any cytotoxicity to the cells at the concentrations used. The results suggest that Phx-3 inhibits C. pneumoniae replication in human monocytic cells as well as epithelial cells, partially depending on the tryptophan-metabolic pathway of host cells. Thus, Phx-3 might be a useful compound for controlling C. pneumoniae growth in cells and may be an alternative conventional therapy.

Aromatase Inhibitors↗

Biosynthesized tea polyphenols inactivate Chlamydia trachomatis in vitro.

Biosynthesized tea polyphenols showed antichlamydial activity against Chlamydia trachomatis D/UW-3/Cx and L2/434/Bu using cell culture. The most active compounds were (-)-epigallocatechin gallate and (-)-epicatechin gallate, followed by (-)-epicatechin (EC). (+)-Epicatechin and (-)-epigallocatechin were intermediate. EC was the least toxic. These results warrant evaluation of tea polyphenols as topical antichlamydial agents.

Anti-Bacterial Agents↗

In vitro inhibitory effects of hinokitiol on proliferation of Chlamydia trachomatis.

The inhibitory effects of hinokitiol (beta-thujaplicin) on Chlamydia trachomatis D/UW-3/Cx were shown by MIC, minimum lethal concentration (MLC), and preinoculation minimal microbicidal concentration assays using HeLa 229 cells. The MIC and the MLC were both 32 microg/ml. Further evaluation of hinokitiol as a topical agent against C. trachomatis is warranted.

Anti-Infective Agents↗

Distribution of Chlamydia trachomatis serovars among female prostitutes and non-prostitutes in Thailand, and non-prostitutes in Japan during the mid-90s.

The distribution of Chlamydia trachomatis serovars in Thailand and Japan during the same period of the mid-90s was determined. Seventy-one C . trachomatis specimens isolated from female patients who visited the Venereal Diseases Center at Bangkok, Thailand in 1994 were used in this study. Of these, 56 patients were prostitutes. Forty-seven specimens obtained from female non-prostitutes who attended the Department of Obstetrics and Gynecology, Saitama Medical School, Japan during the period from 1993 to 1995 were also used in this study. DNA was extracted from these specimens and typing of C. trachomatis serovars was performed by the polymerase chain reaction-restriction fragment length polymorphism method. The identified serovars among prostitutes of Thailand (n = 56)/non-prostitutes of Thailand (n = 15)/non-prostitutes of Japan (n = 47) were as follows: Ba 1/0/2, D 8/1/15, E 11/2/8, F 16/9/8, G 4/0/7, H 3/2/3, I 1/0/1, J 3/0/0, and K 10/1/4. Serovar F was most prevalent (35.2%) in both prostitutes and non-prostitutes from Thailand, followed by serovar E (18.3%). On the other hand, serovar D was the most frequent serovar in non-prostitutes in Japan (31.9%) followed by serovars F (17.0%) and E (17.0%). A difference in the distribution of C. trachomatis serovars of Thailand and Japan was noted.

Adolescent↗

Severe Chlamydophila psittaci pneumonia rapidly diagnosed by detection of antigen in sputum with an immunochromatography assay.

We report a case of severe Chlamydophila (Chlamydia) psittaci pneumonia rapidly diagnosed by detection of antigen in sputum with an immunochromatography assay. The patient was admitted to our hospital because of shock, disturbance of consciousness, accidental hypothermia, and multiple organ dysfunction syndrome, and he recovered after administration of intravenous erythromycin and high-dose methylpredonisolone therapy. Psittacosis was confirmed by detection of 16S rRNA gene of C. psittasi in sputum with multiplex-polymerase chain reaction analysis. Serological responses to C. psittasi, C. trachomatis, and C. pneumoniae were also evaluated, and serological cross-reactivity was observed between each species. We consider that the commercially available immunochromatography assay for Chlamydia species can be helpful for rapid diagnosis of Chlamydia infection of the respiratory tract. Hereafter, further examination will be necessary regarding pretreatment of specimens or detection sensitivity and specificity.

Aged↗