Biomedical subjects

M Koguchi

Publications and source records attributed to M Koguchi.

At least 55 records · Page 3Linked to original sources

PubMed1993

[Antimicrobial activities of polymyxin B against clinically isolated microbial strains. Results of MIC determination including high concentrations].

Minimum inhibitory concentrations (MICs) were determined for polymyxin B (PL-B), gentamicin, ofloxacin and norfloxacin against clinically isolated microbial strains collected since November 1992, and the following conclusions were obtained: 1. Judging from the MIC distribution of PL-B against the studied strains including multi-drug resistant organisms of major strains of family Enterobacteriaceae, such as Escherichia coli, Klebsiella pneumoniae, Enterobacter spp., and Pseudomonas aeruginosa, it appeared that no PL-B resistant strains were detected among those Gram-negative organisms within the antimicrobial spectrum of PL-B. 2. MICs of PL-B against most strains including methicillin resistant Staphylococcus aureus and coagulase-negative staphylococci were distributed between 100 and 800 micrograms/ml. These results supported reports of other investigators that the eradication of Staphylococcus spp. including MRSA (methicillin-resistant S. aureus) was possible by the use of PL-B at 1 mg/ml. 3. MIC distribution of PL-B against organisms of the Bacteroides fragilis group was almost the same as the results described above.

Bacteria↗

PubMed1993

[Antimicrobial activities of sultamicillin against clinical isolates obtained from outpatients].

Minimum inhibitory concentrations (MICs) were determined for sultamicillin (SBTPC), and for other major oral beta-lactam agents against clinically isolated strains collected from outpatients during a period from August, 1992 to February, 1993, and the following conclusions were obtained. 1. The ratio of penicillinase (PCase)-producing strains of Staphylococcus aureus was 96.0% and that of methicillin-resistant S. aureus (MRSA) was 12.0%. MIC90 of SBTPC against S. aureus including MRSA was 6.25 micrograms/ml. No increasing tendency was observed for S. aureus resistant to SBTPC. 2. No resistant strains were found among Streptococcus pyogenes and Enterococcus faecalis against penicillins (PCs) including SBTPC. But PCs and cephems (CEPs) insensitive or resistant Streptococcus pneumoniae were observed in 22.0% among all the strains of S. pneumoniae. 3. 100% of the tested both strains of Escherichia coli and Proteus mirabilis were beta-lactamase producers. 12.0% of the tested strains of Haemophilus influenzae and 16.0% of the strains of Neisseria gonorrhoeae were also beta-lactamase producers. SBTPC showed strong antimicrobial activity against most of these beta-lactamase producing strains. However, in our study of beta-lactamase productivity using plural substrates and test methods, it appeared that a part of strains of E. coli might produce beta-lactamase of "Extended broad-spectrum". MICs of SBTPC and CEPs against those strains were distributed rather in a high range. 4. The results of the study suggested that the resistant strains of S. pneumoniae against PCs and CEPs might be increasing year by year. Some of strains of E. coli, resistance against the 2 agents were observed. It is important to keep observing changes in resistance of such organisms in the future. 5. The antimicrobial activities of SBTPC against clinically isolated strains in this study indicated potential problems such as those mentioned above. It is, however, also confirmed that SBTPC shows still strong antimicrobial activities against most of beta-lactamase producing strains found in daily medical examinations. Taking into consideration of the strong activities of SBTPC against so-called indirect pathogenicity caused by beta-lactamase producing indigenous bacteria reported lately, SBTPC may be a useful antibiotic for community acquired infections in the 1990's.

Ampicillin↗

PubMed1993

[Antimicrobial activities of arbekacin against methicillin-resistant Staphylococcus aureus isolated from patients of a pediatrics ward].

Aiming at measuring the antimicrobial activities of arbekacin (ABK) against the strains of methicillin-resistant Staphylococcus aureus (MRSA), isolated from pediatrics patients in 1992, the minimum inhibitory concentration (MIC) of 8 antibiotics including ABK was determined and the coagulase types of those strains were also examined. The obtained results are summarized as follows. 1. Among coagulase types of a total of 78 strains, Type II, Type IV and Type VII were 84.6%, 12.8% and 2.6%, respectively. No clear difference in coagulase types were observed among their origins of isolation. 2. MIC90 of ABK against 42 strains isolated from the air passage of suspected pneumoniae patients and 36 strains isolated from the blood of suspected septicemia patients were 1.56 micrograms/ml and 3.13 micrograms/ml, respectively, and MIC90 of ABK against the 78 strains was 1.56 micrograms/ml, which was equal to that of vancomycin (VCM). 3. Most of these strains exhibited resistance against multiple antibiotic agents including cefmetazole (CMZ), imipenem (IPM), fosfomycin (FOM) and minocycline. Strains isolated from the blood were mostly resistant to multiple agents, and most of them were especially highly resistant to CMZ and IPM. ABK, however, showed potent antimicrobial activities even to those strains. These results were similar to the results obtained several years ago. 4. Considering the fact that ABK demonstrates not only potent antimicrobial activities against MRSAs isolated from the pediatric patients, but also shows remarkable clinical effects with concomitant use with beta-lactams or FOM, the prospect of ABK use in MRSA infectious diseases of children is excellent.

Aminoglycosides↗

PubMed1993

[The antimicrobial activity of cefteram against recently clinically detected and isolated strains].

In order to examine antibiotic activities of cefteram (CFTM), its minimum inhibitory concentrations (MIC's) and those of other cephem drugs were determined against clinically isolated strains received from July 1990 to June 1991 and from July 1992 to February 1993 from medical facilities throughout the country and against clinically isolated strains detected in our laboratory in samples from patients with various infectious diseases. The obtained results are summarized below. 1. No CFTM-resistant strains were found among beta-streptococci, Klebsiella spp., Proteus mirabilis, Haemophilus influenzae, and Neisseria gonorrhoeae or even when found, they were present in extremely low proportions. 2. It appeared that Streptococcus pneumoniae insensitive or resistant to beta-lactams, as well as cephems-resistant strains of Escherichia coli were increasing. The former included benzylpenicillin (PCG)-insensitive S. pneumoniae (PISP) of PCG-resistant S. pneumoniae (PRSP), and the presence of the latter suggests the possibility of the existence of "Extended broad-spectrum beta-lactamase" producing strains. The MIC's of beta-lactams against the above PISP or PRSP, and against cephems-resistant E. coli tended to be high, but those of CFTM were relatively low (in most cases). 3. Proportions of strains resistant to cephems, including CFTM among Citrobacter spp., Enterobacter spp., Serratia marcescens, Proteus vulgaris, Morganella morganii, and Providencia rettgeri were high, and in addition, the existence of these cephem resistant species suggests an increase in multiple drug resistant strains that show resistance to new quinolone drugs. 4. As mentioned above, CFTM is by no means a perfect drug or utility drug and its antimicrobial activities do not cover some recent isolates with multiple drug resistance. Except problems encountered with so-called "attenuated" strains of bacteria, increases in resistance can only be observed at a level of MIC90's, and as far as MIC80's are concerned, CFTM still is as active as before and may be used in the treatment of most infections we encounter in normal medical practices.

Bacteria↗

PubMed1993

[Bacteriological evaluation of combined effects of vancomycin and beta-lactams. I. Results against methicillin-resistant Staphylococcus aureus].

We previously reported a part of the results we obtained regarding antibacteriological synergism between beta-lactams and vancomycin (VCM) against methicillin-resistant Staphylococcus aureus (MRSA). This paper reports an additional assessment we made subsequently to the previous report regarding antibacterial effects of different beta-lactams and VCM concurrently used against MRSA. Assessed in this study were bacteriological synergistic actions between flomoxef (FMOX) and VCM, latamoxef (LMOX) and VCM, cefpirome (CPR) and VCM and imipenem (IPM) and VCM against MRSA. 1. Synergistic enhancements of therapeutic activities were observed against MRSA with FMOX +VCM, CPR + VCM and IPM + VCM, but the activity of LMOX + VCM was low. 2. Concentration dependencies of actions of these antibiotic agents against MRSA were strong for beta-lactams, but weak for VCM. These observations were opposite of the results for beta-lactams and aminoglycosides, or beta-lactams and tetracyclines against MRSA we reported previously. 3. It appeared that strong synergistic antibacterial effects were obtained with FMOX or CPR concentrations between 8 and 32 micrograms/ml when used with VCM, and IPM concentrations between 4 and 16 micrograms/ml when used with VCM, hence, in the therapy using these combinations, concentrations and dose intervals of beta-lactams employed should be carefully considered. 4. When these antibiotics are used together in in vitro experiments, values of MIC and FIC-index may be different depending upon experimental systems used.

Anti-Bacterial Agents↗

PubMed1993

[Bacteriological evaluation of combined effects of vancomycin and beta-lactams. II. Results against gram-negative rods].

Evaluations were made for antibacterial activities of combination uses of flomoxef (FMOX) + vancomycin (VCM) against clinically isolated bacteria of family Enterobacteriaceae, and latamoxef (LMOX) + VCM, cefpirome (CPR) + VCM, and imipenem (IPM) + VCM against also clinically isolated Pseudomonas aeruginosa. The obtained results are summarized as follows. 1. FMOX and VCM appeared to act independently against Enterobacteriaceae without showing synergism or antagonism. 2. Regarding antibacterial effects of LMOX + VCM, or CPR + VCM against P. aeruginosa strains, MIC values under the combined uses were approximately 1 dilution (2 folds) higher than LMOX or CPR used alone, but we did not consider that these results meant the presence of antagonism between the beta-lactams and VCM. 3. Experimental results suggested that an antagonistic relationship was present between IPM and VCM against P. aeruginosa. The degree of the antagonism was dependent on VCM concentrations. In other words, when VCM is present at a concentration between 4 and 128 micrograms/ml, MIC values for IPM increased 2 to 4 dilutions (4 to 16 folds), whereas in the presence of 1 to 2 micrograms/ml VCM, MIC values for IPM were close to those of IPM alone. Further, some of this tendency was observed for FMOX against bacteria of family Enterobacteriaceae in the presence of VCM. 4. These results suggest that the dose level of VCM should be considered based on a low range when a combination therapy is considered between beta-lactams and VCM in the treatment of infections with MRSA alone or with Gram-negative rods with MRSA.

Anti-Bacterial Agents↗

PubMed1993

[Antibacterial activities of ofloxacin against recent clinical isolates from patients with ocular infections].

In order to study antibacterial activities of ofloxacin (OFLX), minimum inhibitory concentrations (MICs) of OFLX were determined against clinical isolates obtained from ophthalmic institutes all over the country and those isolated and identified from patients with various ocular infections during three years from September 1989 until August 1992, and the results were compared with those of the control drugs. The following results were obtained. 1. Compared with the reports by others presented from 1984 through 1986, increases were observed for strains with moderate or low susceptibilities to OFLX such as Staphylococcus spp., Corynebacterium spp., Serratia spp., and glucose-nonfermentative Gram-negative rods ((G) NF-GNR). 2. Although incidence of resistance to OFLX increased among the above strains, remarkably low frequencies was observed for the occurrence of highly resistant strains to OFLX with MIC value > 100 micrograms/ml. 3. The antibacterial spectrum of OFLX covered (G)NF-GNR, and the activity of OFLX was superior to those of aminoglycosides, penicillins and cephems used as the control drugs. 4. Low incidence of highly resistant strains to OFLX and its broad antibacterial spectrum suggested the usefulness of a 0.3% OFLX ophthalmic solution in achieving concentrations exceeding MIC for a prolonged period of time.

Drug Resistance, Microbial↗

PubMed1993

[Bacteriological evaluations of combination effects with cefotiam and other antimicrobial agents against methicillin-resistant Staphylococcus aureus. I. Synergistic actions of cefotiam with imipenem and vancomycin].

We assessed the bacteriological efficacies of cefotiam (CTM) plus imipenem (IPM) and CTM plus vancomycin (VCM) therapies against methicillin-resistant Staphylococcus aureus (MRSA) in an in vitro system. The results are summarized as follows. 1. It appeared that the bacteriological efficacies of CTM+IPM therapy against MRSA strains were different against different target MRSA strains. In other words, the FIC indices of CTM+IPM were distributed in a wide range of < or = 0.5- > 2.0. The strains showing MIC levels of < or = 8 micrograms/ml in IPM concentrations showed a strong correlation with FIC index values of < or = 0.5, and the strains showing the MIC level of > or = 128 micrograms/ml in IPM concentration showed a strong correlation with FIC index values of > 2.0. Hence, the strains showing FIC indices < or = 0.5 were considered to be newborn strains with penicillin-binding protein 2' (PBP-2'), those showing FIC indices > 0.5- < or = 2.0 were considered to be strains with increasing production in PBP-2', and those showing FIC indices > 2.0 were considered to be strains with increasing productions in both PBP-2' and PBP-m2. In strains with FIC indices higher than 2.0, the 2 drugs may possibly share the action mechanism and the activity center thus they compete with each other.(ABSTRACT TRUNCATED AT 250 WORDS)

Cefotiam↗

PubMed1993

[Bacteriological evaluations of combination effects with cefotiam and other antimicrobial agents against methicillin-resistant Staphylococcus aureus. II. Synergistic actions of cefotiam with arbekacin and minocycline].

We assessed the bacteriological efficacies of cefotiam (CTM) plus arbekacin (ABK) and CTM plus minocycline (MINO) therapies against methicillin-resistant Staphylococcus aureus (MRSA) in an in vitro system. The results are summarized as follows. 1. Both of CTM+ABK and CTM+MINO demonstrated almost perfect antibacterial activities against MRSA strains at ABK and MINO concentrations of MIC levels as clinically expected plasma ABK or MINO levels, and also showed antibacterial activities at ABK or MINO concentrations of sub-MIC levels. But no results suggesting antagonism were obtained. 2. The potent antibacterial effect of CTM+ABK or CTM+MINO against MRSA strains was considered to be the result of damage to the cellular membrane of target strains by ABK or MINO with ABK or MINO concentrations at MIC or sub-MIC levels and by the subsequent antibiotic effect of CTM. 3. A combination of drugs which are different from each other in mechanisms of action and points of action is likely to show a consistent antibacterial effect, but a combination of drugs which are competitive to each other because they share mechanism and point of action possibly cause antagonism.

Aminoglycosides↗

PubMed1993

[Effects of a combination therapy consisting of arbekacin and ampicillin of methicillin-resistant Staphylococcus aureus].

Investigations were made on effects of a combination therapy consisting of arbekacin (ABK) and ampicillin (ABPC) against methicillin-resistant Staphylococcus aureus (MRSA). The following conclusions were drawn. 1. A frequency of FIC index to be < or = 0.5 upon a combination therapy consisting of ABK and ABPC against MRSA was 48.7%, hence this therapy showed better antibacterial effects than the other 8 combination therapies consisting of ABK and other antibiotics previously studied. 2. A combination therapy consisting of ABK and ABPC against MRSA was better than any other combination therapy because ABPC had a higher binding affinity with penicillin-binding protein 3 of MRSA, and because a high antibacterial activity of ABPC was maintained during the combination therapy. ABPC did not lose antibacterial activity largely because MRSA dose not produce beta-lactamase, or most of MRSA produces little beta-lactamase activity. 3. Our data indicate that the success of a combination therapy against MRSA depends upon the effects of the drug under sub MIC concentrations.

Aminoglycosides↗

PubMed1993

[Antibacterial activities of arbekacin against recently isolated methicillin-resistant Staphylococcus aureus (I)].

Against 200 strains of methicillin-resistant Staphylococcus aureus (MRSA) isolated from 1990 to 1991, minimum inhibitory concentrations (MICs) of a total of 15 antibacterial agents including arbekacin (ABK) were determined. In addition coagulase types of the tested strains were determined and classified according on their origins. 1. Among the coagulase types of 200 strains, type II were 63.5%, type IV 18.5%, type VII 11.0% and the other types 7.0%. Type II strains were prevailing among those isolated from the respiratory tract specimens and type IV among those from the surgical specimens. These results were in agreement with other recent reports including our previous ones. 2. The MIC50 of methicillin, 6 cephalosporins (CEPs), imipenem, fosfomycin (FOM), gentamicin, tobramycin and clindamycin for 200 strains ranged from 50 to > 100 micrograms/ml. On the other hand, MIC50 and MIC90 of ABK, minocycline (MINO) and vancomycin (VCM) were 0.78 and 3.13 micrograms/ml for ABK, 0.39 and 50 micrograms/ml for MINO, and 0.78 and 1.56 micrograms/ml for VCM. 3. The MIC90 of ABK against coagulase type IV strains was rather high, 12.5 micrograms/ml. However, the strains inhibited by 6.25 to 12.5 micrograms/ml of ABK were isolated even in our studies performed in 1986, 1988 and 1989. Further studies are therefore required to confirm whether appearance of these strains used in the present study inhibited at relatively high concentrations of ABK is due to the use of ABK. 4. It is reported that, at present, most of the MRSAs spreading in Japan are acceleratedly acquiring resistance to many drugs, and especially, they are developing high resistance against beta-lactams. ABK showed potent antibacterial activities even against these strains. Since ABK has been shown to display potent activities against MRSA in combination with beta-lactams or FOM, we believe ABK is one of the useful aminoglycoside antibiotics for the treatment of MRSA infections.

Aminoglycosides↗

PubMed1993

[Antimicrobial activities of aspoxicillin of fresh clinical isolates].

The Antimicrobial activity of aspoxicillin (ASPC) in terms of minimum inhibitory concentration (MICs) was compared with those of other penicillin antibiotics (PCs) against clinical isolates sent to us from medical institutions throughout Japan in 1988, 1990 and 1992 and strains isolated and identified from samples collected from patients with various infections. 1. The MIC80's of ASPC against Staphylococcus aureus, Enterococcus spp., Escherichia coli, Bacteroides fragilis group were almost the same as those against these isolates in 1985 to 1986. 2. A trend for increasing susceptibility to PCs including ASPC was observed in the isolates of S. aureus and Haemophilus influenzae. This trend in S. aureus was attributed to the appearance of non beta-lactamase producing strains associated with the development of highly resistant strains among the methicillin-resistant S. aureus (MRSA) as well as to a tendency toward yearly decreasing frequency of MRSA. The trend for the increased susceptibility in H. influenzae was related to the decrease in the number of beta-lactamase production strains. 3. The frequency of the strains highly resistant to PCs including ASPC increased. 4. No PCs-resistant strains were observed among the so-called beta-streptococci, while among alpha-streptococci and Streptococcus pneumoniae there was a trend for decreasing frequency of strains with lower susceptibility to PCs or those with resistant to PCs. These strains may be variants which were also resistant to cephems and had penicillin-binding proteins (PBPs). Meanwhile, a high frequency of highly PCs-resistant strains were noted among Enterococcus faecium. In view of the fact that the PCs-resistance of E. faecium is known to be related to PBPs, the pattern of the susceptibility of the recent clinical isolates to beta-lactams is considered to be multimodal.

Amoxicillin↗

PubMed1992

[Antibacterial activity of rokitamycin against fresh clinical isolates].

We obtained bacterial strains which were clinically isolated and identified from outpatients with various infections in medical institutions throughout Japan. Possible antibacterial activities of rokitamycin (RKM) were examined against these isolates. Minimum inhibitory concentrations (MICs) were determined through a comparative study with reference drugs. The results of the study are summarized as follows. 1. Resistance patterns of 400 isolates which were highly resistant to macrolides (MLs) with MIC values > 100 micrograms/ml were classified into 55 patterns. Staphylococcus spp. showed cross resistance to 14-membered ring MLs with 100% cross resistance observed between erythromycin (EM) and clarithromycin (CAM), and 85.2% between EM and oleandomycin (OL). Fewer isolates showed strong resistance to 16-membered ring MLs than to 14-membered ring MLs. Cross resistances observed among the Staphylococcus isolates were 100% between acetylmidecamycin (MDM-AC) and kitasamycin (leucomycin (LM)), 93.9% between MDM-AC and josamycin (JM), and 53.3% between MDM-AC and RKM. Streptococcus spp. and Peptococcus spp. showed very similar resistance patterns to both 14- and 16-membered ring MLs, but resistance patterns to RKM were quite different. Most of anaerobic streptococci and Bacteroides fragilis group had similar resistance patterns to 14- and 16-membered ring MLs, but in some cases a pattern similar to that of Staphylococcus spp. was observed. 2. When ML-resistant bacteria isolated during 1975 to 1980 were compared to those isolated in 1986 and 1989, it was observed that resistance of Staphylococcus aureus remained almost unchanged, that of Streptococcus pyogenes was lower in the later years than during 1975 to 1980, but that of Streptococcus pneumoniae increased. 3. Most of ML-resistances of the resistant isolates were inducible, but extents of induction varied depending on drugs tested. Strong inductions were observed when 14-membered ring MLs were used, but inductions were minimal with 16-membered ring MLs. RKM appeared to induce resistance to the least extent. From these results, it appears that the RKM is quite useful clinically even in the 1990s.

Bacterial Infections↗

PubMed1992

[Combined effects of arbekacin with other antibiotics against methicillin-resistant Staphylococcus aureus. I. The combined effect of arbekacin with fosfomycin or clavulanic acid/ticarcillin].

As arbekacin (ABK) has a highly potent antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA), its combined effects with fosfomycin (FOM) and clavulanic acid/ticarcillin (CVA/TIPC) against MRSA were examined. The obtained results are summarized as follows. 1. Against MRSA either combination, FOM+ABK or CVA/TIPC+ABK showed a strong antibacterial effect at the MIC or the sub MIC of ABK in the blood expected from clinical observations. The MIC of ABK by the combination use seemed to be equivalent to the MBC value. 2. Effective concentrations of antibiotics in these combinations appeared to be strongly dependent on the effective concentration of ABK and less dependent on that of FOM or CVA/TIPC. Therefore, the antibacterial activity of a combination seems to mostly depend on the antibacterial activity and the concentration of ABK. 3. As FOM and CVA/TIPC have antibacterial activities against Pseudomonas aeruginosa, combinations of ABK with these antibiotics are likely to be effective against double infection with P. aeruginosa in MRSA infected patients.

Aminoglycosides↗

PubMed1992

[Combined effects of arbekacin with other antibiotics against methicillin-resistant Staphylococcus aureus. II. The combined effect of arbekacin with imipenem or cefminox].

Combined antibacterial effects of imipenem (IPM)+arbekacin (ABK) and cefminox (CMNX)+ABK against methicillin-resistant Staphylococcus aureus (MRSA) were examined and the obtained results are summarized below. 1. Either combination, IPM+ABK or CMNX+ABK, showed a strong antibacterial effect against MRSA when blood concentration of ABK were sustained at MIC as could be expected in clinical situations. While at sub MICs of ABK the antibacterial effect of these combination was slightly less than those of the previously reported combinations of ABK and other antibiotics. 2. Antibacterial effects of the combinations against MRSA were strongly dependent on the concentration of ABK and less dependent on the concentration of IPM or CMNX. As were observed in the previously tested combinations of ABK with other antibiotics, the antibacterial effect of the combination appeared to be highly dependent on the antibacterial activity and the concentration of ABK. 3. As IPM has potent antibacterial activities against Gram-negative bacteria (GNB) including Pseudomonas aeruginosa while CMNX has potent antibacterial activities against GNB except P. aeruginosa, it is likely that the combinations of IPM+ABK or CMNX+ABK are useful for treatment of infections with MRSA together with GNB.

Aminoglycosides↗

PubMed1992

[Antimicrobial activities of major oral antibacterial agents against clinically isolated microbial strains from inpatients].

Antimicrobial activities were examined for major antibacterial agents against clinically isolated microbial strains which were isolated and identified from materials collected from inpatients with various infections in 1988, 1989 and 1990, and the following conclusions were obtained. 1. Among strains isolated each year, methicillin-resistant Staphylococcus aureus (MRSA) were found frequently. 2. CEPs-resistant Escherichia coli strains were observed among strains isolated each year. 3. Increasing tendencies in resistances of Citrobacter freundii, Enterobacter spp., Serratia marcescens to cephems and new quinolones were observed. 4. Increasing tendencies in resistances of Proteus vulgaris to ceftazidime (CAZ) and new quinolones appeared to exist. 5. Among strains isolated each year, resistances of Pseudomonas aeruginosa to CAZ and quinolones were observed in high rates, but also their resistances to imipenem appeared to increase. 6. Many of recently increasing multiple resistant bacteria seem to have different sites of drug action and/or to have non-hydrolytic modes of resistance.

Anti-Bacterial Agents↗

PubMed1992

[Antimicrobial activities of major oral antibacterial agents against clinically isolated microbial strains from outpatients with respiratory tract infection].

Minimum inhibitory concentrations (MICs) were determined for major oral antibacterial agents for clinically isolated microbial strains from materials collected from outpatients with respiratory tract infections in 1988, 1989 and 1990, and the following conclusions were obtained. 1. Methicillin-resistant Staphylococcus aureus (MRSA) appeared to be responsible for community-acquired respiratory tract infections, but there also was a tendency showing that MRSA increased year by year. 2. A tendency was observed indicating that benzylpenicillin (PCG)-insensitive Streptococcus pneumoniae (PISP) increased year by year. 3. Beta-lactamase-producing strains of Haemophilus influenzae were observed in a certain ratio, and also those of Branhamella catarrhalis were found in high ratios. 4. A tendency of increasing resistance of Klebsiella pneumoniae to new quinolones was observed. 5. It is of a great importance to evaluate methods of selecting primary choice antibiotic agents since increasing numbers of new oral antibacterial agents are becoming rapidly available.

Anti-Bacterial Agents↗

PubMed1992

[Antibacterial activities of sisomicin against fresh clinical isolates].

To investigate antibacterial activities of sisomicin (SISO), MICs of SISO as well as other aminoglycosides (AGs) were determined against many clinical isolates which were obtained in 1991. Results are summarized below: 1. No SISO-resistant strains were observed among isolates of Escherichia coli, Citrobacter diversus, Klebsiella pneumoniae, Klebsiella oxytoca, Enterobacter aerogenes, Proteus mirabilis and Morganella morganii. 2. In comparison with the results of our previous study against isolates obtained in 1986, the rate of methicillin-resistant Staphylococcus aureus (MRSA) was higher, and SISO-resistant strains were observed at a high rate among the MRSA. Also, SISO-resistant strains of Serratia marcescens increased. However, the rate of SISO-resistant strains of Pseudomonas aeruginosa decreased, and among Citrobacter freundii, Enterobacter cloacae and Proteus vulgaris, SISO-resistant strains did not increase over the years. 3. MICs of SISO against Providencia rettgeri and Providencia stuartii were high, suggesting that antibacterial activities of SISO was weak against genus Providencia. 4. For comparison, according to MICs of ofloxacin and imipenem, new quinolone-resistant strains were observed at a high rate among various organisms, and carbapenem-resistant strains were observed at a high rate among S. marcescens and P. aeruginosa. 5. SISO is still one of the useful AGs in the 1990's since it maintains its strong antibacterial activities against most clinical isolates obtained in recent years and its potential as a combination drug with beta-lactams is being reported.

Bacteria↗