Hiroko Yoshida

Osaka Prefectural Medical Center for Respiratory and Allergic Diseases, Ōsaka, Ōsaka, Japan

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Publications (8)3.03 Total impact

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    ABSTRACT: OBJECTIVE; The COBAS TaqMan real-time polymerase chain reaction (PCR) assay (TaqMan assay) is a well-accepted and widely distributed molecular-based diagnostic test for tuberculosis. In the present study, we evaluated the efficacy of the LAMP assay (loopamp MTBC detection kit) as an alternative molecular-based diagnostic kit for tuberculosis, through comparison with the TaqMan assay. STUDY PERIOD AND METHODS: This study was conducted over a period of approximately 2 months, between May and July 2012. We collected 48 samples (43 sputum, 2 gastric fluid, 2 pleural fluid, and 1 pus fluid samples) from patients who had been diagnosed with tuberculosis through the culture method, but had not received any treatment for more than one week. All samples were processed using the CC-E pre-treatment reagent (Japan BCG) prior to performing the TaqMan and LAMP assay. For the TaqMan assay, 100 microL of supernatant was used after centrifugation at 1,000 rpm for 1 minute, whereas 60 microL of the precipitate in the same sample was used for the LAMP assay. In total, 23 out of 48 samples were identified as positive for tuberculosis according to smear microscopy tests, among which 15, 4, and 4 samples had smear test scores or 1+, 2+, and 3+, respectively. All the samples that tested positive in the smear test, regardless of the score, also tested positive in both the TaqMan and TB-LAMP assays (100%). Of the 25 smear-negative samples, we noted that 16 tested positive by the TaqMan assay (64%), whereas 20 tested positive by the LAMP assay (80%). Compared with the TaqMan assay, the LAMP assay showed a higher positive rate among the smear-negative samples. We believe that this is because substances in the samples acted as co-precipitating agents, resulting in the presence of a larger number of bacteria in the precipitates than in the supernatants. Thus, the findings indicate that the application of the LAMP method to precipitates obtained following CC-E pre-treatments may lead to prompt diagnosis of tuberculosis, with a level of sensitivity comparable to that of culture tests.
    Kekkaku: [Tuberculosis] 11/2013; 88(11):727-33.
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    ABSTRACT: Tuberculosis (TB) is a major public health problem. The Airin district of Osaka City has a large population of homeless persons and caregivers and is estimated to be the largest TB-endemic area in the intermediate-prevalence country, Japan. However, there have been few studies of homeless persons and caregivers. The objective of this study is to detect active TB and to assess the prevalence and risk factors for latent TB infection among homeless persons and caregivers. We conducted a cross-sectional study for screening TB infection (active and latent TB infections) using questionnaire, chest X-ray (CXR), newly available assay for latent TB infection (QuantiFERON-TB Gold In-Tube; QFT) and clinical evaluation by physicians at the Osaka Socio-Medical Center Hospital between July 2007 and March 2008. Homeless persons and caregivers, aged 30-74 years old, who had not received CXR examination within one year, were recruited. As for risk factors of latent TB infection, the odds ratios (OR) and 95% confidence intervals (95% CI) for QFT-positivity were calculated using logistic regression model. Complete responses were available from 436 individuals (263 homeless persons and 173 caregivers). Four active TB cases (1.5%) among homeless persons were found, while there were no cases among caregivers. Out of these four, three had positive QFT results. One hundred and thirty-three (50.6%) homeless persons and 42 (24.3%) caregivers had positive QFT results. In multivariate analysis, QFT-positivity was independently associated with a long time spent in the Airin district: ≥10 years versus <10 years for homeless (OR = 2.53; 95% CI, 1.39-4.61) and for caregivers (OR = 2.32; 95% CI, 1.05-5.13), and the past exposure to TB patients for caregivers (OR = 3.21; 95% CI, 1.30-7.91) but not for homeless persons (OR = 1.51; 95% CI, 0.71-3.21). Although no active TB was found for caregivers, one-quarter of them had latent TB infection. In addition to homeless persons, caregivers need examinations for latent TB infection as well as active TB and careful follow-up, especially when they have spent a long time in a TB-endemic area and/or have been exposed to TB patients.
    BMC Infectious Diseases 01/2011; 11:22. · 3.03 Impact Factor
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    ABSTRACT: We investigated the prevalence of isoniazid (INH) resistance-conferring mutations in the INH-indeterminate Mycobacterium tuberculosis (MTB) strains. We initially selected a sample of 47 clinical isolates of MTB from patients, who visited the Osaka Prefectural Medical Center for Respiratory and Allergic Diseases from 2000 to 2005. Strains resistant to the concentration of 1 - 2 microg/ml were defined as "indeterminate". INH resistance-conferring mutations were determined by DNA microarray. Of 47 INH-indeterminate strains, only 13 (27.7%) were found to have no resistance mutations, 23 (48.9%) had mutation within the inhA regulatory region at -15 C to T, and 2 (4.3%) had mutation within the inhA regulatory region at -8 T to A, 6 (12.8%) had mutation within the katG gene at 1778 G to A, and 3 (6.4%) had mutations within the katG gene both at 1778 G to A and at 982 T to G. We showed that the majority of INH-indeterminate strains have resistance-conferring mutations, which were mainly detected within the inhA regulatory region.
    Kekkaku: [Tuberculosis] 01/2007; 81(12):709-13.
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    ABSTRACT: To know the treatment outcome of patients with multidrug-resistant tuberculosis (MDR-TB) during gestation. Retrospective study of 3 cases of pregnant women, who were treated for MDR-TB with a regimen including pyrazinamide, ethambutol, para-aminosalicylic acid, cycloserine and amoxicillin-clavulanic acid. All patients showed a good response to anti-tuberculosis chemotherapy without any serious adverse effect, and were culture-negative at the time of delivery. Two patients delivered vaginally at weeks 40, and one patient delivered surgically at weeks 38. All newborns were healthy, and their tuberculin skin tests and placental tissue examinations were negative for tuberculosis. MDR-TB can be successfully treated during pregnancy by using a regimen including effective second-line anti-tuberculosis drugs.
    Kekkaku: [Tuberculosis] 07/2006; 81(6):413-8.
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    ABSTRACT: To analyze the situation of tuberculosis infection by DNA fingerprinting in the middle and eastern part of Osaka, Japan. We performed IS6110 restriction fragment length polymorphism (RFLP) on 1200 isolates from tuberculosis patients who visited our hospital from January 2001 to December 2003. A cluster was defined as a series of isolates with more than 90% similarity by IS6110 RFLP and those with the same drug-susceptibility pattern. The isolates with fewer than six copies of IS6110 were considered to be clustered if the IS6110 RFLP patterns and the variable numbers of tandem repeats with 16 regions of ETR and MIRU "allele profile" were identical. The number of samples in incremental study periods was 422 in 2001, 817 between 2001 and 2002 and 1200 between 2001 and 2003. The percentage of clustered cases was 27.8% in 2001, 19.1% in 2002 and 19.5% in 2003. The cumulative percentage of clustered cases was 27.8% in the first year, 29.7% over two years and 32.6% over three years. The percentage of clustered cases of isolates with a drug resistance was significantly lower (25.0%) than that of drug susceptible isolates (33.7%). Next, we investigated the clustered cases by gender and age. The percentage of clustered cases with isolates from young males and females (0-19 years old) was 23.8%. In contrast, the percentage of clustered cases with isolates from 20-59 year-old females gradually decreased from 14.7% to 4.4%. Conversely, the percentage of clustered cases from young and middle aged male (20-59 years old) was higher (20.2%-32.4%) than that of females. The sharp increase in the cumulative cluster formation rate was curbed by the decline in the tuberculosis incidence rate in Osaka, Japan, after the first year of examination. We thought that this phenomenon suggests the success of the anti-tuberculosis measure in Japan.
    Kekkaku: [Tuberculosis] 05/2006; 81(4):321-8.
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    ABSTRACT: To examine the direct detection of rifampicin (RFP)-resistant Mycobacterium tuberculosis in sputum by Line Probe Assay (LiPA). We collected 130 sputa and analyzed both by LiPA and the Amplicor M.tuberculosis assay. For culture-positive samples, RFP resistance testing was performed and compared with the results by LiPA. Eighty two out of 84 M. tuberculosis samples were detected by LiPA and all of 10 Mycobacteria other than M. tuberculosis (MOTT) samples and 36 negative samples were negative by LiPA. The detection rate is same as Amplicor. For culture-positive samples, LiPA showed mutation pattern for all of 22 RFP-resistant strains and wild type pattern for 19 of 20 RFP-sensitive strains. The one remaining showed mixed pattern of wild type and mutation pattern. The use of LiPA for sputum coould enable early detection of RFP-resistant tuberculosis and seems to be useful for the control of tuberculosis.
    Kekkaku: [Tuberculosis] 10/2004; 79(9):525-30.
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    ABSTRACT: In this study, we examined the fluctuation in the ratio between strains of tuberculosis bacilli resistant and susceptible to the anti-tuberculosis drugs. We selected the cases in which the bacilli acquired drug resistance during the therapy and the cases in which drug resistance was fluctuating during prolonged anti-tuberculosis treatment. We selected the isolates throughout the medication period, and the selected isolates were separated into respective single colonies. Then we measured the minimal inhibitory concentration (MIC) for each colony by microdilution test for M. tuberculosis complex, BrothMIC MTB-1 (Kyokuto Pharmaceutical Inc., Tokyo). Five patients were eligible for analysis because their medical histories were clearly recorded and drug resistance changed during the course. The MIC of 19 isolates, 202 colonies were measured. Isolates with coexisting drug-resistant and -susceptible colonies were detected in 2 patients. From these results, we considered that the fluctuation in the ratio between drug-resistant and -susceptible bacilli changes with the progression of anti-tuberculosis medication. We showed in this article that the drug-resistant bacilli increased rapidly when the strains acquired the drug resistance during medication, and when the administration of particular anti-tuberculosis drug was stopped, the susceptible bacilli seemed to increase gradually. However, the strain immediately became fully drug-resistant when the particular antibacterial drug was readministered.
    Kekkaku: [Tuberculosis] 12/2003; 78(12):739-46.
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    ABSTRACT: In the antimycobacterial susceptibility test for INH using the egg-based Ogawa media, 3 concentrations (0.1, 1, or 5 micrograms/ml) of INH were used, and 1 microgram/ml was used as a critical concentration for INH resistance. However, it was controversial whether INH 0.1 microgram/ml resistant M. tuberculosis was clinically significant or not. We investigated the MIC values of INH 0.1 microgram/ml resistant strains by using BrothMIC MTB-1 method, and 115 strains of M. tuberculosis confirmed by DNA-prove test were used. The distribution of MIC values of 115 strains determined by Ogawa INH susceptibility test was shown in figure. By BrothMIC MTB-1 method, they were classified into 3 groups; susceptible, low resistant and high resistant groups. The mean MIC value of INH 0.1 microgram/ml resistant M. tuberculosis was estimated to be 4.53 micrograms/ml with its 95% confidence interval 3.21-5.85 micrograms/ml, and they were determined as "resistant" in BrothMIC MTB-1 method. These results supported the idea that patients with INH 0.1 microgram/ml resistant M. tuberculosis strains should be regarded as clinically "resistant".
    Kekkaku: [Tuberculosis] 08/2002; 77(7):533-5.

Publication Stats

19 Citations
3.03 Total Impact Points

Institutions

  • 2003–2011
    • Osaka Prefectural Medical Center for Respiratory and Allergic Diseases
      Ōsaka, Ōsaka, Japan