Biomedical subjects

R Ishihara

Publications and source records attributed to R Ishihara.

At least 55 records · Page 3Linked to original sources

PubMed1996

[Antibacterial activities of combination uses of isepamicin and beta-lactams in vitro against clinically isolated strains. Part 2. The results against enterobacteriaceae].

We investigated antibacterial activities of combination uses of isepamicin (ISP) and beta-lactams in vitro against Klebsiella pneumoniae and Enterobacter cloacae, and the following conclusions were obtained. 1. ISP+cefazolin, ISP+cefotiam and ISP+flomoxef against K. pneumoniae and ISP+piperacillin, ISP+ceftazidime, ISP+aztreonam, ISP+imipenem and ISP+panipenem against E. cloacae showed strong combined effects. 2. The minimum inhibitory concentrations (MICs) of these combinations were low due to the dependence of ISP concentrations. Strong antibacterial activities were observed at sub-MIC levels of ISP. These combined effects were stronger than those against Staphylococcus aureus described in the first report at sub-MIC levels of ISP. 1/4 MIC approximately 1/8 MIC of ISP showed enhanced activities of beta-lactams. Similarly strong combined effects were observed against both beta-lactam-sensitive and -resistant strains.

Anti-Bacterial Agents↗

PubMed1996

[Antimicrobial activities of clarithromycin against clinical isolates].

To examine the antimicrobial activity of clarithromycin (CAM) against strains clinically isolated from outpatients in 1994, minimum inhibitory concentrations (MICs) were determined for CAM and the control drugs. The results were as follows; 1. MIC50 and MIC90 of CAM were similar to those investigated in 1980's against many bacterial species. 2. CAM showed strong antimicrobial activities against beta-lactamase producing Moraxella subgenus Branhamella catarrhalis, Bordetella pertussis, Campylobacter jejuni subsp. jejuni and Peptostreptococcus spp. 3. It appears that resistance to MLs including CAM is increasing among Streptococcus pneumoniae.

Anti-Bacterial Agents↗

PubMed1996

[Antimicrobial activity of cefodizime against clinical isolates].

In order to evaluate antimicrobial activity of cefodizime (CDZM), minimum inhibitory concentrations (MICs) of CDZM and control drugs were determined against clinical isolates collected from nation-wide medical institutions and in our laboratory from September to December of 1992 and from September to December of 1995. The results are summarized as follows: 1. Bacterial species with no or few strains resistant to CDZM included Streptococcus pyogenes, Haemophilus influenzae, Citrobacter koseri, Proteus mirabilis and Neisseria gonorrhoeae. The range of MIC values of CDZM against Klebsiella pneumoniae was spread. Other strains, Streptococcus pneumoniae, Moraxella subgenus Branhamella catarrhalis, Escherichia coli, Citrobacter freundii, Enterobacter spp., Serratia marcescens, Proteus vulgaris, Morganella morganii, Providencia spp., Peptostreptococcus spp. and Bacteroides fragilis group were resistant to cephems including CDZM. 2. The MIC90's of CDZM were 0.05 approximately 3.13 micrograms/ml against Streptococcus spp., H. influenzae, M. (B.) catarrhalis, E. coli, Klebsiella spp., P. mirabilis, N. gonorrhoeae and Peptostreptococcus spp. obtained in 1995 that were frequently found in daily treatment of infections. It appears that the effectiveness of CDZM was still relatively high against community-acquired infections. 3. Among H. influenzae isolates included imipenem (IPM)-resistant and norfloxacin (NFLX)-resistant strains. The MIC-range of CDZM against strains collected in 1995 including IPM-resistant and NFLX-resistant strains was < or = 0.025 approximately 0.1 microgram/ml, and MIC90 against these strains was 0.05 microgram/ml. CDZM showed strong antimicrobial activities against H. influenzae strains resistant to carbapenems and new-quinolones.

Bacteria↗

PubMed1996

[Antimicrobial activities of cefetamet against clinical isolates from urinary tract infection].

In order to evaluate antimicrobial activity of cefetamet (CEMT), minimum inhibitory concentrations (MICs) of CEMT and control drugs were determined against Gram-negative rods mainly from complicated urinary tract infections examined in our laboratory from April to September of 1994. The results are summarized as follows; 1. The obtained strains were Citrobacter diversus 20, Citrobacter freundii 30, Enterobacter aerogenes 20, Enterobacter cloacae 30, Serratia marcescens 30, Proteus mirabilis 30, Proteus vulgaris 20 and Morganella morganii 30 strains, a total of 210 strains. 2. Excluding some resistant strains, the MIC-distribution showed showed that CEMT had strong antimicrobial activities against those strains from the MIC-distribution of this investigation. Compared to reports on CEMT in 1989, the MIC80 of CEMT in this investigation against clinical isolates were similar. The MIC50's of CEMT against E. aerogenes, S. marcescens, P. mirabilis, P. vulgaris and M. morganii in the previous examination were equal to or similar to the current results, but the MIC50's against C. freundii and E. cloacae were lower than the value of this report. The detection frequency of highly resistant strains of C. freundii and E. cloacae to cefteram and cefixime were similar to that of CEMT-resistant strains. Multiple drug resistant strains, among these bacterial species seemed to be increasing. 3. Compared to oral antibacterial agents of oxime cephems that were used in the past, CEMT showed higher peak values of urinary excretion concentration and higher blood levels were sustained for a longer period of time. CEMT-PI will be effective against urinary tract infections.

Ceftizoxime↗

PubMed1995

Induction of endometrial adenocarcinomas by a single intra-uterine administration of N-ethyl-N'-nitro-N-nitrosoguanidine to aged Donryu rats showing spontaneously persistent estrus.

Induction of endometrial adenocarcinomas by a single intra-uterine administration of N-ethyl-N'-nitro-N-nitrosoguanidine (ENNG) to aged rats was examined. Donryu rats showing spontaneously persistent estrus were given a single intra-uterine administration of ENNG (20 mg/kg) at 10 months (44 weeks) of age. At the termination of the experiment (week 34 after the ENNG-treatment), 22% and 13% incidences of endometrial adenocarcinomas were observed in the experimental and control groups, respectively, the difference being without significance. No variation was found in the endocrine environment between experimental and non carcinogen-treated control animals throughout the experimental period. These results show that ENNG-treatment alone is not sufficient in aged rats for high induction of endometrial carcinomas. Comparison of the data with those from our previous studies, in which ENNG was given at a young age (10 weeks of age), indicates that young rats may be more sensitive than their old counterparts.

Adenocarcinoma↗

PubMed1995

[Antimicrobial activities of norfloxacin against clinical isolates from ocular infections].

In order to evaluate antimicrobial activity of norfloxacin (NFLX), minimum inhibitory concentration (MICs) of NFLX and control drugs were determined against clinical isolates from ocular infections that were obtained in our laboratory from July, 1993 to December, 1994. The results are summarized as follows; 1. Compared to MIC distributions of NFLX against clinical isolates from ocular infections studied in 1986 and 1987, the MIC80 of NFLX against Corynebacterium spp., Enterobacter spp., Serratia spp., Burkholderia cepacia, Flavobacterium spp., Alcaligenes spp. increased 8 times. Almost all of NFLX-resistant strains among them were ofloxacin (OFLX)-resistant, new quinolones resistant strains, and a part of them were aminoglycosides, beta-lactams-resistant as well, thus all of these strains were multiple drug resistant. 2. MIC of NFLX against Pseudomonas aeruginosa were lower than that of OFLX. 3. NFLX showed strong antimicrobial activities against so-called "particular bacteria" including Staphylococcus aureus subsp. aureus, Moraxella spp., Haemophilus spp., and P. aeruginosa from ocular infections. And MIC80 of NFLX against these bacteria was 0.05-1.56 microgram/ml. We observed that NFLX eye drops was administered so that concentrations above the MIC against these clinical isolates were maintained.

Anti-Infective Agents↗

PubMed1995

[Study of clinically isolated new quinolones-resistant Haemophilus influenzae. Part 1].

A study was done to determine susceptibilities of Haemophilus influenzae that were obtained in our laboratory in 1994 to new quinolones (NQ) and other drugs. The results were as follows; 1. Among the 300 isolates, the detection frequency of NQ-resistant strains was 8.7% (26 strains), including isolates from chronic lower respiratory tract infections (22 strains) and those from middle meatus of nose (2 strains), etc. NQ-resistant strains were not isolated from children. 2. The cross resistance was studied for different NQs against NQ-resistant strains. Clavulanic acid/amoxicillin, cefteram, cefpodoxime, cefditoren, cefodizime (CDZM) and cefpirome showed strong antimicrobial activities against NQ-resistant strains. MIC90 of CEPs against all isolated strains including NQ-resistant strains and beta-lactamase producers was low. And the MIC90 of CDZM was < or = 0.025 microgram/ml, which was the lowest among all the antibiotics tested. 3. We found 47 strains (15.7%) of beta-lactamase producers among the 300 isolates, the frequency of beta-lactamase producing strains was high among strains obtained from children.

Anti-Infective Agents↗

PubMed1995

[Frequency of clinical isolation of glucose non-fermentative gram-negative rods and their susceptibilities to antibacterial agents].

A comparison was made for frequencies of isolation o glucose non-fermentative Gram-negative rods ((G)NF-GNR) from clinical specimens during a period from July, 1986 to June, 1987 (the first period) and that from January, 1994 to December, 1994 (the second period). Also, minimum inhibitory concentrations of principal drugs were determined against these isolates. The obtained results are summarized as follows: 1. Thirty four (34) species of (G)NF-GNR were found from 35,200 clinical specimens in the two periods. Numbers of strains of (G)NF-GNR obtained were 4,575 during the first period and 4,704 during the second period, thus no significant difference existed in numbers of strains isolated in the two periods. 2. Among the 34 species to which the 4,704 strains were classified into, Pseudomonas aeruginosa comprised 68.4%, Stenotrophomonas maltophilia 6.9%, Acinetobacter baumannii 5.6%, Burkholderia cepacia 3.1%, Acinetobacter Iwoffii 2.6%, Alcaligenes xylosoxidans subsp. xylosoxidans 2.4%, Flavobacterium indologenes 1.7%, Pseudomonas putida 1.1%, Acinetobacter junii 1.1% and Moraxella subgenus Moraxella lacunata 0.9%. When these frequencies of isolation were compared with those in the first period, it was found that B. cepacia decreased significantly (P < 0.01) and that S. maltophilia increased significantly (P < 0.001). 3. MIC determinations revealed multiple drug resistance strains in many different species of bacteria. Minocycline, however, were active against many such strains, and ofloxacin was found to have strong antibacterial activity against some strains.

Anti-Bacterial Agents↗

PubMed1995

[Clinical and bacteriological effects of cefetamet pivoxil against community-acquired respiratory tract infections].

We investigated clinical and bacteriological effects of cefetamet pivoxil (CEMT-PI) in community-acquired respiratory tract infections and obtained the following findings. 1. Of the 420 respiratory tract infection cases that were treated with CEMT-PI according to a same protocol at a total of 42 institutions in Tokyo, Kanagawa-ken, Saitama-ken and Chiba-ken from February to the beginning of April 1994, 359 cases in which clinical evaluations were considered possible were selected as the subjects of the clinical study. Regarding genders of patients, slightly more females (56.3%) than males were included. Diagnoses given to these patients included laryngopharygealitis (60.7%), tonsillitis (14.2%) and acute bronchitis (13.6). Outpatients accounted for 94.4% of the subjects. 2. For the bacteriological study, a written material describing the method of collecting specimens, storage and transport in detail was distributed to the above mentioned institutions. The isolation and identification of suspected causative bacteria, determination of minimum inhibitory concentrations (MIC) and investigation of beta-lactamase production were conducted all together. Suspected causative bacteria were detected from 238 (66.3%) out of the 359 cases. They included 85 strains of Haemophilus influenzae, 76 strains of Streptococcus pneumoniae, 20 strains of Streptococcus pyogenes and 17 strains of Moraxella subgenus Branhamella catarrhalis. 3. Clinical efficacy rates (the ratio of those excellent+good) among those who were treated with 1 CEMT-PI tablet (194 mg, titer) twice a day was 76.5% and among those who were given 2 tablets twice a day was 87.4%. The improvement rate of the latter was higher at a significant level of P < 0.05. 4. The clinical efficacies classified by suspected causative bacteria (single bacterium) were 93.3% against M.(B.) catarrhalis, 91.7% against beta-streptococci, 87.1% against H. influenzae and 78.4% against S. pneumoniae, etc. Though 7 (9.2%) of the 76 strains of S. pneumoniae were benzylpenicillin (PCG)-insensitive S. pneumoniae (PISP), the bacteriological efficacy was assessed either excellent or good in all of the 7 patients from whom PISP were detected. The clinical efficacy was assessed 100.0% in those from which a plural number of bacteria were detected. The 13 cases from which small numbers of Staphylococcus aureus was detected with other bacterium were also included in these cases.

Administration, Oral↗

PubMed1995

[Antibacterial activities of cefmenoxime against recent fresh clinical isolates from patients in sinusitis].

In order to evaluate antimicrobial activity of cefmenoxime (CMX), minimum inhibitory concentrations (MICs) of CMX and control drugs were determined against clinical isolates from patients of sinusitis that were obtained in our laboratory from October of 1993 to March of 1994. The results are summarized as follows; 1. CMX showed strong antimicrobial activities against Streptococcus pneumoniae, Haemophilus influenzae and Moraxella subgenus Branhamella catarrhalis that were 3 major aerobic bacteria from sinusitis. Antimicrobial activities of CMX against benzylpenicillin (PCG)-insensitive S. pneumoniae (PISP) and PCG-resistant S. pneumoniae (PRSP) were stronger than those of ampicillin (ABPC), and these strong activities suggested that CMX might have strong antimicrobial activities against beta-lactamase producing H. influenzae and M. (B.) catarrhalis. 2. Antimicrobial activities of CMX against microaerophiles, Streptococcus constellatus, Streptococcus intermedius and Gemella morbillorum and against Peptostreptococcus spp., from chronic sinusitis and odontogenic maxillary sinusitis, were stronger than those of most of the control drugs. 3. The MIC90's of CMX against isolates from patients of sinusitis were < or = 0.025-0.39 micrograms/ml. These values were lower than transitional concentrations in mucous membrane of maxillary sinus obtained when "1% CMX nasal solution" was used with nebulizer. It appears likely that sufficient concentrations exceeding MICs against main organisms would be obtained by nebulizer treatment using CMX nasal solution.

Cefmenoxime↗

PubMed1995

[Detection of bacteria in urine using dip-slides (1). Possible occurrence of false-negative results when dip-slides are used for urine containing antibacterial agents].

Dip-slides are used as semiquantitative microbial sampling devices that are simple to use in routine testing of urine to detect the presence of bacteria, and are recommended for use in "Standard evaluation of drug efficacy in UTI". Bacterial growth on currently available dip-slides, however, may conceivably be influenced by the presence of antibacterial agents in urine. We studied clinical performance of, and effects of antibacterial agents on, such dip-slides, using two types of dip-slides, URICULTE and DIASLIDE, both of which are newly developed urine culture devices. The quantitative conventional culture method was also used as the control. 1. When single species of bacteria are present in urine specimens of patients, results obtained using URICULTE and DIASLIDE agreed very well, and they, in turn agreed well with results obtained using the quantitative, conventional culture method, also. 2. When urine specimens were spiked with Gram-negative rods and Gram-positive cocci together, URICULTE fail to provide quantitative results because colonies were not well separated and confluent growth often resulted because of a large sample volume this device employs. DIASLIDE which used a smaller amount of sample, on the other hand, provided quantitative results with adequate separation of colonies. 3. When three antibacterial agents were added to urine specimens that were spiked with bacteria, DIASLIDE produced significantly higher numbers of colonies than URICULTE. The difference probably are due to the difference in volumes of specimens used in the two devices, the former device employs approximately 1/100 as much volume of specimen as the latter.(ABSTRACT TRUNCATED AT 250 WORDS)

Anti-Bacterial Agents↗

PubMed1995

[Antibacterial activities of fosfomycin against recent clinical isolates from patients of otitis media and otitis externa].

Clinical isolates from patients with otitis media and/or otitis externa were collected at otorhinology clinics nationwide and sent to us during 1989, 1991 and 1993. Minimum inhibitory concentrations (MICs) of fosfomycin (FOM) and of reference drugs against these strains were determined to investigate year-to-year antibacterial activity of FOM. A comparative analysis of the results revealed trends described below. 1. The MIC90 of FOM against Staphylococcus aureus subsp. aureus increased 4 times by 1993 as compared to those measured for strains isolated in 1984 and 1985, when FOM for otic use was under development. This was thought to be due to the recent increase in the detection frequency of methicillin-resistant S. aureus (MRSA) which is also resistant to FOM. 2. No annual changes were seen for MIC distribution of FOM against Proteus group and Pseudomonas aeruginosa. 3. Since there was no large annual change in the antibacterial activity of FOM against recent clinical isolates obtained from patients with otitis media and/or otitis externa, FOM may be considered as one of the useful drugs even now, in the mid-1990's.

Drug Resistance, Microbial↗

PubMed1995

[Beta-lactamase production of clinically isolated bacteria].

We examined beta-lactamase productions by clinically isolated strains of bacteria. The results were as follows; 1. It appears that beta-lactamases produced by strains of five species of Staphylococcus spp. are mostly penicillinase (90%). Source of beta-lactamase producing strains of Haemophilus influenzae (23%) and all of Moraxella subgenus Branhamella catarrhalis: strains (100%) are "High & Low producer" strains. 2. A large proportion of beta-lactamase producing strains of Enterobacteriaceae and Bacteroides fragilis group appeared to be "High producer" 3. beta-lactamase producing abilities are different among glucose non-fermentative Gram-negative rods. It appears that some of the strains appeared to be "High producers".

Bacteria↗

PubMed1995

[Antimicrobial activities of sulbactam/ampicillin against clinically isolated microbial strains].

Antimicrobial activities were examined for sulbactam/ampicillin (SBT/ABPC) against clinically isolated microbial strains in 1987, 1990, 1994. Besides, the beta-lactamase productivity and MICs of these strains were measured, and the following conclusions were obtained. 1. The ratio of beta-lactamase producing strains were 90% of methicillin (DMPPC)-susceptible Staphylococcus aureus subsp. aureus (MSSA), about 80% of DMPPC-resistant S. aureus (MRSA), 100% of Escherichia coli, Klebsiella pneumoniae subsp. pneumoniae and Proteus mirabilis, 95% of Moraxella subgenus Branhamella catarrhalis and 15-20% of Haemophilus influenzae. Several kinds of beta-lactamase productivity were observed. 2. Antimicrobial activities of SBT/ABPC against beta-lactamase producing strains of MSSA, M. (B.) catarrhalis, H. influenzae, and almost all of Enterobacteriaceae were stronger than those of ampicillin (ABPC) and piperacillin (PIPC), but antimicrobial activities of SBT/ABPC were weak against MRSA and cephems (CEPs)-resistant strains detected in some of Enterobacteriaceae. 3. It appeared that benzylpenicillin (PCG)-insensitive Streptococcus pneumoniae (PISP) or PCG-resistant S. pneumoniae (PRSP) and CEPs-resistant Escherichia coli increased year by year. 4. Antimicrobial activities of SBT/ABPC were strong against Streptococcus pyogenes, S. pneumoniae, M. (B.) catarrhalis and H. influenzae including beta-lactamase producing strains. Additionally, beta-lactamase inhibiting effect of SBT was observed against beta-lactamase produced by S. aureus and K. pneumoniae which demonstrate indirect pathogenicity. Thus, SBT/ABPC is an injectable antibiotic that is expected to demonstrate clinical usefulness, especially as the first line drug for the respiratory tract infections that are community-acquired.

Ampicillin↗

PubMed1995

[Antimicrobial activities of piperacillin against fresh clinically isolated strains].

In order to evaluate the antimicrobial activity of piperacillin (PIPC), along with control agents, minimum inhibitory concentrations (MIC's) were determined against fresh clinically isolated strains from January to June, 1994. 1. The MIC70's of PIPC against major strains were approximately equal to those reported in the mid 1980s. 2. Strains for the study were supplied in approximately equal numbers from community-acquired hospitals and general hospitals. The ratios of bacteria resistant to beta-lactams including PIPC were low in the former group and high in the latter. 3. "New types of beta-lactam-resistant strains" which did not exist in mid 1980s but found at this time included benzylpenicillin (PCG)-insensitive Streptococcus pneumoniae, PCG-resistant S. pneumoniae, cephems-resistant Escherichia coli and beta-lactamase producing Prevotella spp. These bacteria were also found among strains obtained from community-acquired hospitals.

Bacteria↗

PubMed1995

[Antimicrobial activities of clavulanic acid/ticarcillin against clinical isolates].

In order to investigate antimicrobial activities of clavulanic acid/ticarcillin (CVA/TIPC) against Escherichia coli, Enterobacter spp. and Pseudomonas aeruginosa in 1992 and 1994, beta-lactamase activities were analyzed and minimum inhibitory concentrations (MICs) were determined including those of the control drugs. The results are as follows; 1. Compared to a report in 1980, the MIC distributions of CVA/TIPC against E. coli and P. aeruginosa did not show large differences. We found, however, that CVA/TIPC-resistant strains increased among Enterobacter spp. 2. Almost all of CVA/TIPC-resistant strains of Enterobacter spp. were also resistant to cephems and new quinolones, thus they were multiple drug resistant. 3. CVA/TIPC showed strong antimicrobial activities against penicillinase producing E. coli.

Bacterial Infections↗

PubMed1995

[Antimicrobial activities of cefepime against clinically isolated strains].

In order to evaluate antimicrobial activity of cefepime (CFPM), minimum inhibitory concentrations (MICs) of CFPM and other drugs were determined against clinical isolates that were obtained in 1994. 1. CFPM showed a wide antibacterial spectrum against Staphylococcus spp. and glucose non-fermentative Gram-negative rods ((G)NF-GNR). Antimicrobial activities of CFPM against Staphylococcus spp. were stronger than those of ceftazidime (CAZ) and somewhat stronger than those of cefotaxime (CTX), and antimicrobial activity of CFPM against Pseudomonas aeruginosa was same as that of CAZ. 2. Antimicrobial activities of CFPM against almost all of Enterobacteriaceae were stronger than those of CAZ and CTX. And CFPM showed strong antimicrobial activities against CAZ-resistant Escherichia coli, Citrobacter freundii and Enterobacter spp. 3. Antimicrobial activities of CFPM were weaker than those of CAZ against some of strains of Klebsiella oxytoca, beta-lactamase high producing strains of Moraxella subgenus Branhamella catarrhalis and than those of CTX against beta-lactamase high producing strains of Prevotella spp. 4. The feature of new cephems was demonstrated in that CFPM had wider antibacterial spectrum than cephems of previous genenations against Staphylococcus spp. and (G)NF-GNR and CFPM showed strong antimicrobial activities against almost all of oxacephem-resistant Enterobacteriaceae.

Bacteria↗

PubMed1995

[Antimicrobial activities of clavulanic acid/amoxicillin against freshly isolated clinical strains from outpatients].

In order to investigate antimicrobial activities of clavulanic acid/amoxicillin (CVA/AMPC) against freshly isolated clinical strains obtained in 1995, beta-lactamase activities and minimum inhibitory concentration (MICs) were determined including those of the control drugs. The results are summarized as follows; 1. Detection frequencies of beta-lactamase producing strains were as follows: methicillin-susceptible Staphylococcus aureus subsp. aureus (MSSA, 90.0%), Haemophilus influenzae (22.0%), Moraxella subgenus Branhamella catarrhalis (100.0%), Escherichia coli (100.0%), Klebsiella pneumoniae subsp. pneumoniae (100.0%) and Neisseria gonorrhoeae (14.0%). It appeared that beta-lactamases produced by these strains were mostly penicillinase or enzyme of similar that. 2. Antimicrobial activities of CVA/AMPC against beta-lactamase producing strains were stronger than those of AMPC, and MIC90 of CVA/AMPC against benzylpenicillin (PCG)-insensitive or resistant Streptococcus pneumoniae was lower than those of sultamicillin, cefaclor and cefpodoxime. 3. CVA showed strong beta-lactamase inhibitory effect against M.(B.) catarrhalis of direct and indirect pathogenicity. We can expect CVA/AMPC to negate or decrease the influence of indirect pathogenicity.

Amoxicillin↗