Biomedical subjects

Y Hirakata

Publications and source records attributed to Y Hirakata.

At least 55 records · Page 3Linked to original sources

PubMed1998

[Analysis of utility of the phenotyping method on detection of cases infected by multiple strains of methicillin-resistant Staphylococcus aureus (MRSA)].

In this study, we compared the types of methicillin-resistant Staphylococcus aureus (MRSA) isolated from several foci of the same patient to find the incidence of multiple strain infection of MRSA in bacteremia cases. We will also evaluate the utility of the typing methods of phenotyping and genotyping for the above mentioned objective and judge the dissimilarity of clinical characteristics between the single strain infection and multiple strains infection. We studied 21 cases of MRSA bacteremia who were culture-positive both from blood and other foci in the same patient at Nagasaki University Hospital during 1990-1994. Clinical data were retrospectively collected from the patients' records. Phenotyping of all 113 MRSA isolates were done by coagulase typing (I-VIII), production of enterotoxins (SEA-SED) and toxic shock syndrome toxin-1 (TSST-1), hemolysis typing and antibiogram (MIC). In addition, typing of the same isolates were done by Pulsed-Field Gel Electrophoresis (PFGE), using Gene Navigator System as the genotyping. Several types of MRSA were found from different foci in the same patient in 8 of 21 cases (38%) by phenotyping. The same typing results were obtained in 7 of 8 the multiple strains isolated cases by PFGE. Two types were obtained from another case by phenotyping, but by PFGF, 3 types were obtained. We consider that phenotyping method is convenient and reliable for judgment of the difference in types isolated from different foci in the same patient, but PFGE possibly provide us more detailed epidemiological information. The epidemiological investigation must be done very carefully, especially in immunocompromised hosts as MRSA bacteremia cases, because the chance of multiple strains infection is relatively high among these cases.

Bacteremia↗

PubMed1998

[Pulmonary infection in the emphysematous bulla due to Mycobacterium szulgai diagnosed by percutaneus needle aspiration].

A 73-year-old male was admitted to our hospital because of productive cough and infiltrate on the chest roentogenogram. The underlying diseases was found to be multiple myeloma. He received a physical examination in June, 1996. The chest X-ray and CT scan on admission showed an infiltrative shadow with multiple bulla in the left upper lung field. Internal use of antibiotics and drip infusion of IPM/CS were ineffective. The chest X-ray showed air-fluid level in left upper peripheral bullous lesion and a percutaneus needle aspiration of the lung was performed. The specimen was pus with blood and microscopical examination of smears revealed no acid-fast bacilli, but Mycobacterium szulgai was isolated and identified by DNA-DNA hybridization method. The patient was treated with isoniazid and rifampicin, and improved in a few months. There are a few case reports of pulmonary infection due to M. szulgai associated with emphysematous bulla of the lung in Japan. M. szulgai infection of the lung is similar to M. kansasii infection in respect to clinical features (improvement of chest abnormal shadow, efficacy of drug).

Aged↗

PubMed1998

[A study of virulence factors produced by MRSA strains isolated from blood samples].

Toxic shock syndrome toxin-1 (TSST-1) and enterotoxins are important virulence factors produced by Staphylococcus aureus. It is reported that these toxins are associated with septic shock and toxic shock syndrome. We investigated the toxin production and coagulase types of 701 MRSA strains isolated in Sasebo City General Hospital between 1994 and 1996 TSST-1 or/and enterotoxins were detected in 67% of all MRSA strains, and those were detected in 88% of MRSA strains isolated from blood samples. 45% of all MRSA strains produced both TSST-1 and enterotoxin C, and 70% of MRSA strains obtained from blood produced those toxins. Frequency of TSST-1 or/and enterotoxin production by MRSA strains isolated from blood samples was significantly higher than that by MRSA strains isolated from urine and pharynx (p < 0.05), and frequency of both TSST-1 and enterotoxin C production by MRSA isolates from blood was significantly higher than that by MRSA strains isolated from pharyngeal sample (p < 0.05). This study indicated that investigation of virulence factors produced by MRSA might give the useful information on prevention and treatment of MRSA infection.

Bacteremia↗

PubMed1998

Effect of interleukin-10 on gut-derived sepsis caused by Pseudomonas aeruginosa in mice.

We evaluated the protective effect of interleukin-10 (IL-10) against murine gut-derived sepsis caused by Pseudomonas aeruginosa. Gut-derived sepsis was induced by administering cyclophosphamide and ampicillin while feeding P. aeruginosa to specific-pathogen-free mice. Treating mice with recombinant human IL-10 (rhIL-10) at 1.0 or 5.0 microg/mouse twice a day following the second cyclophosphamide administration significantly increased the survival rate compared to that of control mice treated with saline; however, treatment with rhIL-10 at 0.1 microg/mouse did not result in significant protection. Bacterial counts in the liver, spleen, and blood were all significantly lower in mice treated with rhIL-10 than in saline-treated control mice. Treatment with rhIL-10 significantly suppressed tumor necrosis factor alpha, interleukin-1beta, interleukin-6, and gamma interferon levels in the serum of mice following induction of gut-derived sepsis. We also studied the effect of IL-10 on leukocyte recovery after cyclophosphamide treatment of mice. Administration of rhIL-10 intraperitoneally at 1. 0 microg/mouse significantly accelerated the recovery of leukocytes in comparison with that of the group of saline-treated controls. These results indicate that IL-10 shows a protective effect against gut-derived P. aeruginosa sepsis. We suspect that the mechanism of this effect is that IL-10 regulates in vivo production of inflammatory cytokines. Furthermore, acceleration of leukocyte recovery by IL-10 after cyclophosphamide-induced depression may also play an important role in this protection.

Animals↗

PubMed1998

In vitro activities of quinupristin-dalfopristin and the streptogramin RPR 106972 against Mycoplasma pneumoniae.

The in vitro activities of quinupristin-dalfopristin and streptogramin RPR 106972 were determined with 44 strains of Mycoplasma pneumoniae and compared to those of macrolides, minocycline, and quinolones. All isolates tested were highly susceptible to macrolides and to quinupristin-dalfopristin (MIC at which 90% of the isolates are inhibited [MIC90], 0.0625 microg/ml), followed by RPR 106972 (MIC90, 0.5 microg/ml), quinolones, and minocycline.

Anti-Bacterial Agents↗

PubMed1998

Efficacy of NS-718, a novel lipid nanosphere-encapsulated amphotericin B, against Cryptococcus neoformans.

In vitro and in vivo efficacies of NS-718, a lipid nanosphere-encapsulated amphotericin B (AMPH-B), have been studied. Of the tested AMPH-B formulations, NS-718 had the lowest MIC for Cryptococcus neoformans. In a murine model, low-dose therapy (0.8 mg/kg of body weight) with NS-718 showed higher efficacy than that with AmBisome. High-dose therapy (2.0 mg/kg) with NS-718 was much more effective than those with Fungizone and AmBisome. In mice treated with a high dose of NS-718, only a few yeast cells had grown in lung by 7 days after inoculation. A pharmacokinetic study showed higher concentrations of AMPH-B in lung following administration of NS-718 than after administration of AmBisome. Our results indicated that NS-718, a new AMPH-B formulation, is a promising antifungal agent for treatment of pulmonary cryptococcosis and could be the most effective antifungal agent against C. neoformans infections.

Amphotericin B↗

PubMed1998

Rapid detection and evaluation of clinical characteristics of emerging multiple-drug-resistant gram-negative rods carrying the metallo-beta-lactamase gene blaIMP.

Gram-negative rods (GNR) carrying the transferable carbapenem resistance gene blaIMP, including Pseudomonas aeruginosa and Serratia marcescens, have been isolated from more than 20 hospitals in Japan. Although the emergence of such multiple-drug-resistant bacteria is of utmost clinical concern, little information in regard to the distribution of blaIMP-positive GNR in hospitals and the clinical characteristics of infected patients is available. To address this, a system for the rapid detection of the blaIMP gene with a simple DNA preparation and by enzymatic detection of PCR products was developed. A total of 933 ceftazidime-resistant strains of GNR isolated between 1991 and 1996 at Nagasaki University Hospital, Nagasaki, Japan, were screened for the blaIMP gene; 80 isolates were positive, including 53 P. aeruginosa isolates, 13 other glucose-nonfermenting bacteria, 13 S. marcescens isolates, and 1 Citrobacter freundii isolate. Most of the patients from whom blaIMP-positive organisms were isolated had malignant diseases (53. 8%). The organisms caused urinary tract infections, pneumonia, or other infections in 46.3% of the patients, while they were just colonizing the other patients evaluated. It was possible that blaIMP-positive P. aeruginosa strains contributed to the death of four patients, while the other infections caused by GNR carrying blaIMP were not lethal. DNA fingerprinting analysis by pulsed-field gel electrophoresis suggested the cross transmission of strains within the hospital. The isolates were ceftazidime resistant and were frequently resistant to other antibiotics. Although no particular means of pathogenesis of blaIMP-positive GNR is evident at present, the rapid detection of such strains is necessary to help with infection control practices for the prevention of their dissemination and the transmission of the resistance gene to other pathogenic bacteria.

DNA Fingerprinting↗

PubMed1998

Adherence to and penetration of human intestinal Caco-2 epithelial cell monolayers by Pseudomonas aeruginosa.

Clinical isolates of Pseudomonas aeruginosa from blood adhered to and penetrated intestinal Caco-2 cell monolayers to a greater degree than did isolates from sputum, with a concomitant drastic decrease in transepithelial electrical resistance. PAO-PR1, an avirulent exotoxin A mutant of PAO1, did not cause a decrease in the resistance. The Caco-2 monolayer system may be useful for the evaluation of certain P. aeruginosa virulence factor activities.

Bacterial Adhesion↗

PubMed1998

Genetic relationship between blood and nonblood isolates from bacteremic patients determined by pulsed-field gel electrophoresis.

A total of 148 isolates from 55 bacteremic patients were examined by pulsed-field gel electrophoresis. Genetically different nonblood strains were isolated from 13.9% of patients with bacteremia caused by gram-positive cocci and 42.1% with Pseudomonas aeruginosa bacteremia, indicating that antibiograms of a single nonblood P. aeruginosa isolate are not always informative for treatment of bacteremia.

Bacteremia↗

PubMed1998

Antimicrobial susceptibility testing of Bilophila wadsworthia isolates submitted for routine laboratory examination.

MICs of antibiotics against Bilophila wadsworthia isolates were measured by agar and broth microdilution with pyruvic acid and by Etest. The inoculum size influenced greatly agar dilution. Despite discrepancies in MICs depending on the measurement method used, clindamycin consistently showed potent activity. Broth microdilution and Etest appear to be candidates for laboratory susceptibility testing.

Aged↗

PubMed1998

Detection of Mycobacterium tuberculosis in preserved tuberculous lymph nodes by polymerase chain reaction.

We evaluated the usefulness of three types of polymerase chain reaction (PCR) targeting 16S rRNA, protein antigen b and IS6110 in detecting Mycobacterium tuberculosis in preserved tuberculous lymph nodes. The detection limit of all PCR methods was 100 colony forming unit (CFU) of M. tuberculosis in tissue. The test samples included eight paraffin-embedded tuberculous lymph nodes containing microscopical epithelioid cell granuloma with caseous necrosis and Langhans giant cells. Although acid-fast stained organisms in lymph node tissue were not detected in any sample, all three types of PCR tests were positive in four of eight lymph nodes. Our results suggest that PCR is not only a rapid and sensitive diagnostic method for tuberculous lymphadenitis, but also clinically significant in retrospective study for detecting M. tuberculosis even in some preserved lymph node tissues without evidence of acid-fast stained organisms.

Antigens, Bacterial↗

PubMed1998

[In vitro antibacterial activities of cefteram and other beta-lactam agents against recent clinical isolates].

In vitro antibacterial activity of the third-generation oral cephem cefteram (CFTM)--ten years after its first use in the clinical setting--against recent clinical isolates was evaluated and compared with those of other oral cephems. A total of 851 clinical isolates belonging to 13 species used in this study were collected from five medical institutions across Japan during 1996. CFTM showed excellent antibacterial activity against methicillin-susceptible S. aureus and S. pyogenes, equivalent to those of other third-generation oral cephems, except cefixime. Of the S. pneumoniae strains, a high proportion, 34.1%, were penicillin-resistant strains (PRSP), with MIC values of 2.0 micrograms/ml or above, but the MIC50 of CFTM against PRSP was 1.0 microgram/ml. CFTM and the other third-generation oral cephems showed potent antibacterial activity against E. coli, K. pneumoniae, and P. mirabilis. A few strains of E. coli, however, were highly resistant to third-generation oral cephems; that might include extended-spectrum beta-lactamase producing strains. MIC values against P. vulgaris varied significantly, depending on whether they were determined by the broth micro-dilution method or the agar dilution method; growth was observed at high concentrations in the broth micro-dilution method, in which the skip phenomenon was demonstrated, but not in the agar dilution method. The reason for this discrepancy is unknown. Most strains of S. marcescens, C. freundii, and E. cloacae demonstrated resistance to CFTM and the other third-generation oral cephems. CFTM and the other third-generation oral cephems showed excellent antibacterial activities against M. (B.) catarrhalis, N. gonorrhoeae, and H. influenzae, including ampicillin-resistant strains.

Ampicillin Resistance↗

PubMed1997

Comparison between Wako-WB003 and Fungitec G tests for detection of (1-->3)-beta-D-glucan in systemic mycosis.

The limulus factor G reacts with (1-->3)-beta-D-glucan, a major structural component of fungal cell walls. The Fungitec G test is a colorimetric assay that measures the concentration of (1-->3)-beta-D-glucan and is used as a serodiagnostic test for deep mycosis. Wako-WB003 is another assay for (1-->3)-beta-D-glucan that determines the change in turbidity of the gelatin reaction of limulus factor G with (1-->3)-beta-D-glucan. In five rabbits inoculated intravenously with 1 x 10(7) CFU of Candida albicans, the concentration of (1-->3)-beta-D-glucan measured by the fungitec G test increased gradually reaching a peak of 660.9 +/- 427.9 pg/ml (mean +/- SD) 4 days after inoculation, but to 42.225 +/- 41.275 ng/ml on day 6 in the Wako-WB003 test. In one rabbit challenged intravenously with 5 x 10(6) CFU of C. albicans, (1-->3)-beta-D-glucan increased to 101.5 pg/ml on day 4 on the fungitec G test, whereas the level remained below the detection limit of the Wako-WB003 test throughout the course of the disease. We also detected high concentrations of (1-->3)-beta-D-glucan in 11 patients with candidemia, 4 with suspected candidemia, 1 with invasive pulmonary aspergillosis, and 12 patients with aspergilloma. The concentration of (1-->3)-beta-D-glucan measured by the Fungitec G test was > 150, > 1006.8; 312.1, and 55.6 +/- 37.4 pg/ml (range, 20.1-138.0 pg/ml), and by the Wako-WB003 test > 153.000, > 17.70, 153.000 and 2.645 +/- 7.248 ng/ml (range, < 25.20 ng/ml) in these patients, respectively. In contrast, the concentration of (1-->3)-beta-D-glucan in 9 patients with pulmonary cryptococcosis and 6 with superficial candida colonization ranged from < 13.2 and < 15.3 pg/ml in the Fungitec G test and < 0.53 and < 0.12 ng/ml in Wako-WB003 test. There was a weak relationship between the concentration of (1-->3)-beta-D-glucan measured by the Fungitec G test and Wako-WB003 test (r = 0.521). Our results indicate that the sensitivity of the Wako-WB003 test is lower than that of the Fungitec G test.

Animals↗

PubMed1997

Adverse effects of tumour necrosis factor in cyclophosphamide-treated mice subjected to gut-derived Pseudomonas aeruginosa sepsis.

To evaluate the role of tumour necrosis factor (TNF) in gut-derived sepsis, mice were given Pseudomomas aeruginosa strain D4 by bacterial suspension in their drinking water during which time ampicillin (200 mg/kg) was given to disrupt the normal indigenous bacterial flora. Cyclophosphamide was additionally administered to induce bacterial translocation of the P. aeruginosa that had colonized the gastrointestinal tract, and thereby to cause gut-derived sepsis. In this model, TNF-alpha was detected in serum from the next day after the second cyclophosphamide administration, increasing to level of 3 ng/ml in lethal conditions. Average serum TNF-alpha level was significantly higher in mice with bacteraemia than in those without bacteraemia. Treatment with 0.8 microg/kg of recombinant human TNF-alpha (rhTNF-alpha) did not affect the mortality, whereas administration of either 4 and 20 microg/kg of rhTNF-alpha significantly increased the mortality rate in comparison with saline-treated mice. Bacterial counts in liver and blood were significantly higher in 20 microg/kg of rhTNF-alpha treated mice than in saline-treated mice. Treatment with murine anti-TNF-alpha monoclonal antibody significantly reduced the mortality from septic infection. We conclude that TNF-alpha may facilitate bacterial translocation and causes deterioration of gut-derived sepsis due to P. aeruginosa in mice.

Animals↗

PubMed1997

Differential diagnosis of tuberculous pleurisy by measurement of cytokine concentrations in pleural effusion.

STUDY OBJECTIVE: Measurement of cytokine concentration in serum and pleural effusion may be useful in the differential diagnosis of tuberculous pleurisy. PATIENTS AND METHODS: We compared the biochemical properties and concentrations of cytokines in serum and pleural effusion samples of 18 patients with tuberculous pleurisy, 7 patients with parapneumonic pleurisy, and 25 patients with malignant pleurisy. RESULTS: A high value of adenosine deaminase (ADA) was observed in pleural effusion of patients with tuberculosis. The serum concentrations of interleukin (IL)-1-beta, IL-2, interferon (IFN)-gamma and tumor necrosis factor (TNF)-alpha were similar among the three groups. However, the concentration of IFN-gamma in pleural effusion was high in tuberculous patients, and that of TNF-alpha was high in tuberculous and parapneumonic pleural fluid, but both cytokines were low in malignant pleural fluid. The sensitivity, specificity and accuracy of IFN-gamma in the diagnosis of tuberculous pleurisy were 94%, 100% and 98%, respectively. Similarly, those of TNF-alpha for the diagnosis of infectious pleurisy including tuberculous and parapneumonic pleurisy were 88%, 80% and 84%, respectively. CONCLUSIONS: Our results indicate that simultaneous measurement of IFN-gamma and TNF-alpha in pleural effusion is a useful diagnostic tool for differentiating tuberculous pleurisy from parapneumonic and malignant pleurisy.

Adult↗

PubMed1997

Genetic relationship of penicillin resistant Streptococcus pneumoniae serotype 19B strains in Japan.

Pulsed field gel electrophoresis (PFGE) of the genomic DNA of penicillin resistant serotype 19B Streptococcus pneumoniae was carried out. Thirteen strains form the Nagasaki area and 12 strains from other areas in Japan were examined. Twenty-three strains were resistant to erythromycin, tetracycline and trimethoprim/sulfamethoxazole but susceptible to chloramphenicol. Eight strains were resistant to ceftriaxone. All strains were multiply resistant. Five strains isolated from Nagasaki were indistinguishable from each other by using restriction enzymes Apa I and Sma I. Two strains isolated from other areas were indistinguishable from the above five strains. We could classify 13 Nagasaki strains into 3 groups and the total of 25 Japanese strains into 6 groups. These results suggest that the increasing prevalence of multiply drug resistant S. pneumoniae serotyped 19B in Japan is not due to a single clone, but at least one clone has spread widely in Japan.

DNA, Bacterial↗

PubMed1997

In vitro susceptibility studies and detection of vancomycin resistance genes in clinical isolates of enterococci in Nagasaki, Japan.

Glycopeptide resistance in enterococci is now a cause of clinical concern in the United States and Europe. However, details of vancomycin resistance in enterococci in Japan have been unknown. We measured minimum inhibitory concentrations (MICs) of various antimicrobial agents for a total of 218 clinical strains of enterococci isolated in our hospital in 1995-6 in addition to 15 strains with known genotypic markers of resistance. We also screened vancomycin resistance genes using a single step multiplex-PCR. In clinical isolates, only two strains of Enterococcus gallinarum were of intermediate resistance to vancomycin (MIC, 8 micrograms/ml), while the others were all susceptible. Glycopeptides (vancomycin and teicoplanin) and streptogramins (RP 58500 and RPR 106972) showed potent antimicrobial effects for the isolates. In addition, ampicillin was also potent for Enterococcus faecalis, while ampicillin, minocycline and gentamicin were potent for Enterococcus avium. No vanA or vanB genes were detected, while vanC1 and vanC23 genes were detected from two and four strains, respectively. Our results suggest that incidence of VRE in Japan may be estimated as still very low at this time.

Anti-Bacterial Agents↗

PubMed1997

Quantitative characterization and potential function of membrane Fas/APO-1 (CD95) receptors on leukaemic cells from chronic B and T lymphoid leukaemias.

The expression and function of the Fas-receptor (Fas-R) were examined in chronic lymphocytic leukaemia (CLL), hairy cell leukaemia-variant (HCL-v) and adult T-cell leukaemia (ATL). The expression of Fas-R in freshly isolated leukaemic cells was qualitatively and quantitatively different between each disease; faint in B-CLL, moderate in HCL-v and strong in ATL. Both full-length and alternatively spliced truncated forms of Fas mRNA were detected even in CLL B cells with faint to negative Fas-R, and Fas mRNA was also shown to be capable of increasing in vitro expression, i.e. the message was functional. In contrast, Fas-R expression on ATL cells was heterogenous and usually intense with a mean density approximately 3-fold higher than that of normal T cells. Fas-R was confirmed to have the potential function for anti-Fas monoclonal antibody-mediated cell death in vitro in Fas-R+ ATL cells. The expression level of Fas-R on the cells was higher in chronic than acute ATL (10,360 v 6260 antibody-binding capacity per cell, mFasABC; P<0.05) and was inversely correlated with serum LDH activity, suggesting that the strong Fas-R accounts for the slow progression of chronic ATL and the negative Fas-R protects from Fas-mediated cell death. These results show that Fas-R expression on leukaemic cells is valuable in their characterization and perhaps their function, and may contribute to the progression and immune evasion of malignant clones.

Apoptosis↗