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Keizo Yamaguchi

Publications and source records attributed to Keizo Yamaguchi.

At least 37 records · Page 2Linked to original sources
PubMed2006

[Comparative studies on activities of antimicrobial agents against causative organisms isolated from patients with urinary tract infections (2004) II. Background of patients].

Six hundred six bacterial strains isolated from 490 patients diagnosed as having urinary tract infections (UTIs) in 14 institutions in Japan were collected between August 2004 and July 2005. The frequency of bacteria isolation stratified with patient clinical background was compared. The clinical background investigated included sex, age, type of infections, timing of antibiotics administration, and presence or absence of surgery affecting a decrease in defense against infection. The bacterial strains were stratified with the age and sex of the patients and the types of infections. In males, the number of patients aged less than 60 years was few and the complicated UTIs without indwelling catheter was observed most frequently. In females, the number of patients aged less than 60 years was comparatively more than in males. In all of ages except 0-19 and > or = 80 years, the ratio of the uncomplicated UTIs was high, accounting for 44.1-90.0% of all types of infections. In the present time, the bacteria most frequently isolated were Escherichia coli. Pseudomonas aeruginosa and Enterococcus faecalis also were relatively frequently isolated. E. coli most frequently isolated with the uncomplicated UTIs and P. aeruginosa and E. faecalis most frequently isolated with the complicated UTIs. With respect to the relation of these results to the age of the patients, in the uncomplicated UTIs, the isolation frequency of E. coli was the highest in all age groups except 0-19 years, accounting for 50% or higher. In the complicated UTIs without indwelling catheter, the isolation frequency of E. coli tended to be high in all age groups. In the complicated UTIs with indwelling catheter, P. aeruginosa were more frequently isolated. In comparison of causative bacteria in UTIs between before and after the administration of antibiotics, P. aeruginosa increased after the administration in any types of UTIs. In comparison of causative bacteria in UTIs with or without surgery, E. coli was more frequently isolated in the patients without surgery, while P. aeruginosa and E. faecalis were more frequently isolated in the patients with surgery in any UTIs.

Adult↗
PubMed2006

[Comparative studies on activities of antimicrobial agents against causative organisms isolated from patients with urinary tract infections (2004). III. Secular changes in susceptibility].

The bacteria (Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Klebsiella spp. and Pseudomonas aeruginosa) isolated from patients diagnosed as urinary tract infections (UTIs) in 14 institutions in Japan were collected between August 2004 and July 2005. The susceptibilities of these bacteria to various antimicrobial agents were measured. The bacteria were divided into 2 groups consisting of uncomplicated UTIs and complicated UTIs (with and without indwelling catheter) based on their isolation origins. The results were compared with those obtained between 1995 and 2003. The drug sensitivity of S. aureus in this year was similar to those in up to the previous year and S. aureus showed the best susceptibility to vancomycin (VCM) and arbekacin (ABK). The drug sensitivity of E. faecalis in this year also was similar to those in up to the previous year. The susceptibility of E. coli to cephems in this year was generally good and was similar to those in up to the previous year. MIC90 of cefozopran (CZOP) was the most stable and 0.125 microg/mL or less since 1995. The susceptibility of E. coli to cefpirome (CPR) and cefotiam (CTM) also was good but to cefaclor (CCL), cefixime (CFIX), and cefpodoxime (CPDX) was largely decreased in complicated UTI groups. The sensitivity of E. coli to carbapenems also was good but to carumonam (CRMN) tended to decrease. The susceptibility of E. coli to quinolones, however, has largely changed and has decreased since 2003 in uncomplicated UTIs and 2000 in complicated UTIs. That was suggested the development of the resistance to the drug. The susceptibility of Klebsiella spp. to cefazolin (CEZ), CTM, CCL, CPDX, and cefditoren (CDTR) decreased in the previous year and recovered to the year before the previous year in this year. The susceptibility of Klebsiella spp. to other cephems was stable since 1995, especially against CZOP, the highest sensitivity (MIC90: < or = 0.125 microg/mL) was maintained. The susceptibility of Klebsiella spp. to carbapenems and CRMN also was good. The susceptibility of Klebsiella spp. to aminoglycosides was lower than to CZOP but was stable since 1995. The susceptibility of P. aeruginosa was generally low and has largely changed against the majority of the agents since 1995. The susceptibility of P. aeruginosa isolated from uncomplicated UTIs has largely changed against ceftazidime (CAZ), cefsulodin (CFS), CZOP, imipenem (IPM), meropenem (MEPM), aztreonam (AZT), CRMN, gentamicin (GM), and tobramycin (TOB). The susceptibility of P. aeruginosa isolated from complicated UTIs has largely changed against CSF, CZOP, MEPM, GM, and ciprofloxacin (CPFX). The susceptibility of P. aeruginosa isolated from complicated UTIs has been stable against amikacin (AMK). For annual changes in MIC50, TOB and IPM had a relatively stable and high activity (MIC50: 0.5-2 microg/mL).

Anti-Bacterial Agents↗
PubMed2005

Evaluation of dipicolinic acid for detection of IMP- or VIM- type metallo-beta-lactamase-producing Pseudomonas aeruginosa clinical isolates.

We evaluated dipicolinic acid (DPA) as a chelating agent for detection of IMP- or VIM-type metallo-beta-lactamase (MBL)-producing Pseudomonas aeruginosa clinical isolates. Using the broth microdilution testing in the presence or absence of DPA, MBL producers exhibited 100%, 92%, or 100% of >or=8 times (media, 32 times) reduction of MICs in presence of DPA for ceftazidime, imipenem, or meropenem, respectively. In disk diffusion testing, expansion of growth inhibitory zone of these clinical isolates was clearly observed. Thus, DPA could be useful in the detection for MBL-producing P. aeruginosa clinical isolates.

Anti-Bacterial Agents↗
PubMed2005

Interleukin-1-deficient mice exhibit high sensitivity to gut-derived sepsis caused by Pseudomonas aeruginosa.

BACKGROUND: The role of interleukin (IL)-1 in infectious diseases is controversial; some investigators indicated an enhancing effect of IL-1 on host resistance whereas others demonstrated the protective role of IL-1 receptor antagonist in infection. We evaluated the role of endogenous IL-1 in gut-derived sepsis caused by Pseudomonas aeruginosa, by comparing IL-1-deficient mice and wild-type (WT) mice. METHODS: Gut-derived sepsis was induced by intraperitoneal injection of cyclophosphamide after colonization of P. aeruginosa strain D4 in the intestine. RESULTS: The survival rate of IL-1-deficient mice was significantly lower than that of WT mice (P<0.01). Bacterial counts in the liver, mesenteric lymph node and blood were significantly higher in IL-1-deficient mice than in WT mice. Tumor necrosis factor alpha and IL-6 in the liver were significantly higher in IL-1-deficient mice than in WT mice. In vitro, phagocytosis and cytokine production by macrophages were impaired in IL-1-deficient mice compared with WT mice. CONCLUSION: Our results indicate a critical role for IL-1 during gut-derived P. aeruginosa sepsis. The results also suggest that both impairment of cytokine production and phagocytosis by macrophages are caused by IL-1 deficiency and lead to impaired host response.

Animals↗
PubMed2005

Dietary patterns and colorectal adenomas in Japanese men: the Self-Defense Forces Health Study.

The role of dietary patterns in colorectal carcinogenesis remains unclear in Asian populations. Using 1999-2002 data, the authors investigated the association between dietary patterns and colorectal adenomas in 1,341 Japanese men who underwent total colonoscopy. Information about diet was obtained using a 74-item food frequency questionnaire prior to the colonoscopy. Three dietary patterns were generated by factor analysis: 1) a high-dairy, high-fruit and -vegetable, high-starch, low-alcohol pattern; 2) an "animal food" pattern; and 3) a Japanese pattern. Logistic regression analysis was used to estimate the odds ratio of having colorectal adenomas with the adjustment for potential confounding variables including body mass index, smoking, alcohol, and leisure-time physical activities. A significant inverse association was found for the high-dairy, high-fruit and -vegetable, high-starch, low-alcohol pattern; the odds ratios for the second, third, and fourth quartiles were 0.97 (95% confidence interval: 0.70, 1.36), 0.71 (95% confidence interval: 0.50, 1.01), and 0.62 (95% confidence interval: 0.43, 0.90), respectively, compared with the lowest (p(trend) = 0.003). Similar associations were observed for larger adenomas or for each subsite of the colorectum. The Japanese and "animal food" patterns were not clearly associated with colorectal adenomas. A dietary pattern including greater consumption of dairy products and fruits and vegetables with low alcohol consumption may be associated with decreased risk of colorectal adenomas.

Adenoma↗
PubMed2005

Investigation of the susceptibility trends in Japan to fluoroquinolones and other antimicrobial agents in a nationwide collection of clinical isolates: a longitudinal analysis from 1994 to 2002.

The susceptibilities of clinical isolates to fluoroquinolones (FQs) and other antimicrobial agents were surveyed to obtain an accurate understanding of the trends in incidence and antimicrobial resistance. The samples were collected from across Japan, biennially, between 1994 and 2002 and a defined level of resistance to FQ determined. Streptococcus pneumoniae and Haemophilus influenzae exhibited stable and high rates of susceptibility to FQ over the period examined. For methicillin-resistant Staphylococcus aureus the rate of resistance to FQ was 80%-90%, markedly higher than that of methicillin-susceptible S. aureus. The rate of FQ-resistant Escherichia coli increased rapidly to approximately 10% for samples after 2000. Of 696 E. coli isolates collected in 2002, 13 produced an extended-spectrum beta-lactamase (ESBL), with 6 of 13 ESBL-producing isolates being FQ-resistant. No FQ resistance in clinical isolates of Salmonella spp. was detected in any of the surveys. The rate of FQ resistance to Pseudomonas aeruginosa isolated from urinary tract and respiratory tract infections was 40%-60% and 15%-25%, respectively.

Anti-Bacterial Agents↗
PubMed2005

Evaluation of antimicrobial activity of beta-lactam antibiotics using Etest against clinical isolates from 60 medical centres in Japan.

An antimicrobial resistance surveillance study was carried out in 60 medical centres across Japan. Resistance to piperacillin was 10.8% in clinical isolates of Escherichia coli, while 1.3% or fewer isolates were resistant to other beta-lactams. Klebsiella spp. were more susceptible to imipenem, cefepime and cefpirome. Isolates of Enterobacter spp., Citrobacter spp., indole-positive Proteus and Serratia spp. were susceptible to imipenem, cefepime and cefpirome, while Acinetobacter spp. were most susceptible to cefoperazone/sulbactam, imipenem, ceftazidime (5.8% resistance) and cefepime (7.6%). Isolates of Pseudomonas aeruginosa were more susceptible to ceftazidime (12.3% resistance), cefoperazone/sulbactam (12.5%) and cefepime (12.6%) than to piperacillin (15.0%), cefpirome (22.6%) and imipenem (30.8%). The percentage of Japanese imipenem resistant P. aeruginosa clinical isolates was around 30%.

Anti-Bacterial Agents↗
PubMed2005

PROTEKT 1999-2000: a multicentre study of the antimicrobial susceptibility of respiratory tract pathogens in Japan.

DESIGN: A six-centre study in Japan during the winter of 1999-2000 assessed the in vitro activity of >20 antimicrobial agents against the common respiratory pathogens Streptococcus pneumoniae, Streptococcus pyogenes, Haemophilus influenzae, and Moraxella catarrhalis. The minimum inhibitory concentrations (MIC) of each antimicrobial was determined against these isolates using National Committee for Clinical Laboratory Standards (NCCLS) methodology. RESULTS: Among S. pneumoniae isolates, 44.5% were penicillin resistant. The macrolide resistance rate was 77.9% with 90.5% of penicillin-resistant strains also being macrolide resistant. Resistance mechanisms in macrolide-resistant isolates were identified as mef(A) or erm(B) in 42.5% and 52.5%, respectively. Of the fluoroquinolone-resistant isolates (1.3%), most were also penicillin and macrolide resistant. All strains were inhibited by telithromycin at <or=1mg/L. Among S. pyogenes isolates, erythromycin resistance was 17.5% overall but showed considerable variation among the six centres. For H. influenzae, 8.5% produced beta-lactamase and a single beta-lactamase-negative, ampicillin-resistant isolate (0.36%) was obtained, and there was no fluoroquinolone resistance. All isolates were susceptible to telithromycin. Most antimicrobials showed good activity against M. catarrhalis, although 96.7% were beta-lactamase positive. CONCLUSION: The prevalence of antimicrobial resistance to macrolides, penicillin and the fluoroquinolones among the common respiratory pathogens is high in Japan.

Anti-Bacterial Agents↗
PubMed2005

Compensatory response of IL-1 gene knockout mice after pulmonary infection with Klebsiella pneumoniae.

This study was designed to determine the role of interleukin (IL)-1 in the inflammatory response against experimentally induced pneumonia caused by Klebsiella pneumoniae. The host immune responses of IL-1 gene knockout (IL-1 KO) mice and immunocompetent wild-type (WT) mice were compared after pulmonary infection with K. pneumoniae. There were no significant differences between the survival rates and viable bacterial counts in lungs and blood of IL-1 KO and WT mice after pulmonary infections under different conditions. Histopathological analysis showed a similar inflammatory response in both groups of mice. However, in the early stage of infection, the level of tumour necrosis factor alpha (TNF-alpha) in homogenized lungs of IL-1 KO mice was significantly higher than in WT mice. To determine the role of endogenous TNF-alpha in the recovery of the defence mechanism in IL-1 KO mice, mice were treated with an anti-TNF-alpha mAb before infection with K. pneumoniae. The results revealed a significantly lower survival rate of anti-TNF-alpha mAb-treated IL-1 KO mice than BSA-treated IL-1 KO mice. The data suggest that compensatory production of TNF-alpha in IL-1 KO mice contributes to the host defence against K. pneumoniae infection.

Animals↗
PubMed2005

Metallo-beta-lactamase IMP-1 in Providencia rettgeri from two different hospitals in Japan.

In 2002, 495 indole-positive proteae strains were isolated from patients at 60 hospitals in Japan. Nine indole-positive proteae strains had reduced susceptibility to imipenem (MIC > or = 8 microg ml(-1)) and were identified as Providencia rettgeri by BD Phoenix. Eight of the nine Prov. rettgeri isolates were confirmed as metallo-beta-lactamase producers by the double-disc synergy test. All the metallo-beta-lactamases were classified as IMP-1 by PCR and DNA sequence analysis. These bla(IMP-1) genes were encoded in the integron structure on conjugative plasmids. These plasmids could transfer from Prov. rettgeri clinical isolates to Escherichia coli ML4903 at a frequency between 1.5 x 10(-5) and 5.5 x 10(-7). The eight bla(IMP)-positive strains were isolated from two hospitals, and showed two different PFGE patterns, two different integron structures and two different incompatibility groups, which corresponded to the two hospitals. These results strongly suggest the possibility of nosocomial infections by bla(IMP-1)-producing Prov. rettgeri isolates.

Anti-Bacterial Agents↗
PubMed2005

Genetic polymorphisms of methylenetetrahydrofolate reductase and aldehyde dehydrogenase 2, alcohol use and risk of colorectal adenomas: Self-Defense Forces Health Study.

Methylenetetrahydrofolate reductase is a key enzyme in folate metabolism, which affects DNA synthesis and methylation and is possibly linked to colorectal carcinogenesis. Alcohol and acetaldehyde have an adverse effect on folate metabolism. This study investigated the relationship of functional MTHFR C677T and ALDH2 polymorphisms to colorectal adenomas with reference to alcohol consumption in a case-control study of male officials in the Self-Defense Forces (SDF) who received a preretirement health examination at two SDF hospitals. The study subjects were 452 cases of colorectal adenoma and 1050 controls with no polyp who underwent total colonoscopy. Genotypes were determined by the PCR-RFLP method using genomic DNA extracted from the buffy coat. Statistical adjustment was made for age, hospital, rank in the SDF, body mass index, cigarette-years and alcohol intake. Neither MTHFR C677T nor ALDH2 showed a measurable association with colorectal adenoma. While high alcohol consumption was associated with a moderately increased risk of colorectal adenoma, neither of the two polymorphisms showed a significant effect on the association between alcohol and colorectal adenoma. Individuals with the variant alleles ALDH2*2 and MTHFR 677T had a decreased risk of colorectal adenomas, showing adjusted odds ratios of 0.70 (95% confidence interval 0.49-1.00) for all adenomas and 0.57 (0.34-0.95) for large adenomas (> or = 5 mm), as compared to individuals with ALDH2*1/1 and MTHFR 677CC genotypes combined. The findings may be interpreted as suggesting that folate inhibits the growth of colorectal adenomas, but further confirmation is needed.

Adenoma↗
PubMed2005

Kinetics study of KPC-3, a plasmid-encoded class A carbapenem-hydrolyzing beta-lactamase.

The kinetic activity of KPC-3, a plasmid-encoded class A carbapenemase, was studied. It hydrolyzed penicillins, cephalosporins, carbapenems, and even sulbactam. The best substrate was cephalothin (k(cat/K)m = 3.48 microM(-1) s(-1)). The efficiency of the enzyme was similar for imipenem and meropenem (k(cat)/K(m), 1.4 and 1.94 microM(-1) s(-1), respectively).

Amino Acid Sequence↗
PubMed2005

Novel SHV-derived extended-spectrum beta-lactamase, SHV-57, that confers resistance to ceftazidime but not cefazolin.

A new SHV-derived extended-spectrum beta-lactamase, SHV-57, that confers high-level resistance to ceftazidime but not cefotaxime or cefazolin was identified from a national surveillance study conducted in Taiwan in 1998. An Escherichia coli isolate resistant to ampicillin, cephalothin, and ceftazidime but sensitive to cefoxitin, ceftriaxone, cefotaxime, imipenem, and a narrow-spectrum cephem (cefazolin) was isolated from the urine of a patient treated with beta-lactam antibiotics. Resistance to beta-lactams was conjugatively transferred with a plasmid of about 50 kbp. The pI of this enzyme was 8.3. The sequence of the gene was determined, and the open reading frame of the gene was found to consist of 861 bases (GenBank accession number AY223863). Kinetic parameters showed that SHV-57 had a poor affinity to cefazolin. The K(m) value toward cefazolin (5.57 x 10(3) muM) was extremely high in comparison to those toward ceftazidime (30.9 muM) and penicillin G (67 muM), indicating its low affinity to cefazolin. Although the K(m) value of the beta-lactamase inhibitor was too high for the study of catalytic activity (k(cat)), indicating the low k(cat) of SHV-57, the SHV-57 carrier was highly susceptible to a beta-lactam-beta-lactamase inhibitor combination. Comparison of the three-dimensional molecular model of SHV-57 with that of the SHV-1 beta-lactamase suggests that the substitution of arginine for leucine-169 in the Omega loop is important for the substrate specificity.

Cefazolin↗
PubMed2005

Extended-spectrum-beta-lactamase-producing Escherichia coli strains isolated from farm animals from 1999 to 2002: report from the Japanese Veterinary Antimicrobial Resistance Monitoring Program.

A nationwide surveillance for antimicrobial susceptibility in Escherichia coli strains isolated from food-producing animals in Japan was conducted from 1999 to 2002. Eighteen cefazolin-resistant E. coli strains were isolated from broilers. Six were CTX-M-type producing, and eight were CMY-2 producing, while eight had mutations at the ampC promoter region.

Animals↗
PubMed2005

Legionella pneumophila evades gamma interferon-mediated growth suppression through interleukin-10 induction in bone marrow-derived macrophages.

We examined the roles of Th1-Th2 cytokine cross talk in Legionella pneumophila-infected bone marrow-derived (BM) macrophages in the presence of costimulation with interleukin-12 (IL-12) and IL-18. Treatment with gamma interferon (IFN-gamma) alone or treatment with IL-12 in combination with IL-18 resulted in a 3- or 2-log reduction in bacterial numbers, respectively, in BM macrophages, whereas treatment with IL-12 or IL-18 alone had no effect. Significant amounts of IFN-gamma were detected in the culture supernatants of infected macrophages stimulated with IL-12 and IL-18 in combination but not independently. Neutralization of IFN-gamma by antibody completely abolished the growth inhibitory effects of IL-12 and IL-18. Interestingly, higher infectivity ratios of L. pneumophila or the addition of increasing concentrations of heat-killed bacteria (HKB) suppressed the production of IFN-gamma, which resulted in the increased intracellular growth of bacteria. Significant amounts of IL-10 were detected in culture supernatants when Legionella-infected macrophages were cocultured with HKB. Furthermore, neutralization of IL-10 by antibody resulted in an increase in IFN-gamma production by infected BM macrophages when cocultured with HKB. Treatment of HKB with trypsin but not polymyxin B attenuated the growth-promoting effects of HKB, suggesting the involvement of a protein component(s) in regulation of the growth of L. pneumophila. These findings demonstrate a crucial role of Th1-Th2 cross talk in L. pneumophila-infected BM macrophages. Our results also suggest that L. pneumophila modulates the cytokine balance from IFN-gamma-driven Th1 to more Th2 responses, likely through the induction of IL-10 by a bacterial protein component(s). These data provide new insights not only into the cellular mechanisms of Th1-Th2 cross talk in Legionella-infected macrophages but also into the pathogenesis of L. pneumophila pneumonia in humans.

Animals↗
PubMed2005

Clonal diversity of metallo-beta-lactamase-possessing Pseudomonas aeruginosa in geographically diverse regions of Japan.

The aim of this study was to determine the distribution of metallo-beta-lactamase-producing Pseudomonas aeruginosa in Japan and to investigate the molecular characteristics of resistance gene cassettes including the gene encoding this enzyme. A total of 594 nonduplicate strains of P. aeruginosa isolated from 60 hospitals throughout Japan in 2002 were evaluated. This study indicated that although the prevalence of imipenem-resistant P. aeruginosa has not increased compared to that found in previous studies, clonal distribution of the same strain across Japan is evident.

Anti-Bacterial Agents↗
PubMed2005

Extended-spectrum beta-lactamase-producing Shiga toxin gene (Stx1)-positive Escherichia coli O26:H11: a new concern.

Escherichia coli strain TUM2139 was isolated from a stool sample from a 9-year-old girl on 16 June 2004. This strain was categorized as Shiga toxin-producing Escherichia coli (STEC) because the Shiga-like toxin gene stx(1) was detected by immunochromatography and PCR assay. The strain was highly resistant to cefotaxime (256 microg/ml) and was also resistant to cefepime, cefpodoxime, ceftriaxone, and aztreonam. In the presence of 4 microg of clavulanic acid per ml, the MIC of cefotaxime decreased to < or =0.12 microg/ml, indicating that this strain was an extended-spectrum beta-lactamase (ESBL) producer. Cefotaxime resistance was transferred to E. coli C600 by conjugation at a frequency of 3.0 x 10(-6). A PCR assay was performed with primer sets specific for TEM-type and SHV-type ESBLs and for the CTX-M-2 (Toho-1), CTX-M-3, and CTX-M-9 groups of ESBLs. A specific signal was observed with the primer set specific for the CTX-M-9 group of beta-lactamases. This beta-lactamase was confirmed to be the ESBL CTX-M-18 by DNA sequencing. This is the first report of an ESBL-producing STEC isolate.

Child↗