Biomedical subjects

M Koguchi

Publications and source records attributed to M Koguchi.

At least 91 records · Page 5Linked to original sources

PubMed1991

[Antibacterial activities of ofloxacin against recent isolates from patients with community-acquired infections].

In order to survey antibacterial activities of ofloxacin (OFLX) against 1,440 bacterial strains isolated from patients with community-acquired infections in 1987 and 1990, minimum inhibitory concentrations (MICs) of the drug as well as those of other new quinolones and oral cephems were determined. The following conclusions were reached. 1. Comparison of the MIC distribution for strains isolated in 1987 with those in 1990 suggested a tendency toward an increase in the frequency of OFLX-resistant isolates with the passage of time of Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Citrobacter spp., Klebsiella ssp., Enterobacter spp., Proteus vulgaris, Morganella morganii, Providencia spp., and Acinetobacter calcoaceticus. Most common elevations of MIC values against these bacteria were observed in MIC80 and MIC90 values, while no significant alteration was observed in MIC50 values. However, MIC50's of OFLX against Serratia marcescens and Pseudomonas aeruginosa were relatively high for strains isolated in both 1987 and 1990. Most of the OFLX-resistant strains of S. aureus seemed to be methicillin-resistant (MRSA). Furthermore, MIC80 of OFLX against coagulase-negative staphylococci was high in strains isolated in both 1987 and 1990. 2. Susceptibility of Streptococcus spp. was evaluated only in strains isolated in 1990. The results were comparable to those reported by others in the early 1980s. 3. Bacteria which showed no or infrequent emergence of OFLX-resistant strains even in 1990 were Proteus mirabilis, Haemophilus influenzae, Neisseria gonorrhoeae, Campylobacter spp. and Peptostreptococcus spp. 4. Recently isolated strains from patients with community-acquired infections showed a tendency toward an increase of the frequency of OFLX-resistant strains among many bacteria. However, the bacteria which contained high percentages of OFLX-resistant strains except for MRSA were so-called less-virulent bacteria, and in the other bacteria elevations of MIC values were only observed in MIC80 and MIC90. These results suggested that OFLX preserved a potent antibacterial activity against bacteria which were major causative pathogens in community-acquired infections.

Bacteria↗

PubMed1991

[Antibacterial activity of ciprofloxacin against fresh clinical isolates from superficial suppurative foci].

The minimum inhibitory concentrations (MICs) of 5 drugs (ciprofloxacin (CPFX), and 4 drugs used as standard) were determined to investigate antibacterial potencies of CPFX against bacterial strains isolated in 1989 from superficial suppurative foci. The clinical isolates tested included 375 strains from 11 aerobic bacterial species, and 50 strains from 2 anerobic bacterial genera (group) for a total of 425 isolates. Interpreting MIC level distributions of these drugs as the expression of antibacterial potencies, the results are as follows. 1. When activities of new-quinolone antibiotics were tested, we found that, CPFX expressed far superior antibacterial potency to ofloxacin (OFLX) and norfloxacin (NFLX) against coagulase-negative staphylococci, Enterococcus faecalis, Enterococcus faecium, Escherichia coli, Klebsiella pneumoniae, Enterobacter cloacae, Proteus mirabilis, Proteus vulgaris, Morganella morganii, Pseudomonas aeruginosa and Peptostreptococcus spp., although the activity of CPFX against Bacteroides fragilis group was weaker than that of OFLX, and CPFX had similar activity against Staphylococcus aureus to OFLX. 2. In comparison to beta-lactam antibiotics, CPFX was inferior to amoxicillin (AMPC) against E. faecalis and inferior to AMPC and cefaclor (CCL) against Peptostreptococcus spp. Against all other bacterial species, however, CPFX expressed superior antibacterial potency to AMPC and CCL. 3. Scattered findings of low sensitivity or resistance to CPFX were observed among the S. aureus, E. faecalis, E. faecium, P. vulgaris, M. morganii, P. aeruginosa and B. fragilis (group) species, but with an exception of E. faecium, the incidence of resistance strains was low.

Amoxicillin↗

PubMed1990

[Study on susceptibilities of freshly isolated strains to macrolide antibiotics].

Macrolide (ML) susceptibilities of clinically isolated bacteria obtained freshly during 1989 were determined and year to year differences in ML-resistances of the clinical isolates in our laboratory were examined with epidemiological consideration in mind. 1. The distribution of minimum inhibitory concentrations (MICs) of MLs against isolates of Staphylococcus aureus showed 2 peaks, one peak representing S. aureus isolates susceptible to MLs and the other peak representing those resistant to MLs. Proportions of resistant isolates to various MLs were 36% to erythromycin, 24% each to kitasamycin, josamycin, midecamycin and midecamycin acetate. MICs of rokitamycin (RKM), however, distributed themselves into 3 peaks of less than or equal to 0.39 micrograms/ml (76%), 1.56-3.13 micrograms/ml (12%) and greater than or equal to 100 micrograms/ml (12%). Staphylococcus spp. including Staphylococcus epidermidis showed different resistance characteristics to 14-membered ring MLs and to 16-membered ring MLs. Further, the proportion of resistant organisms to RKM was the smallest among proportions of resistant organisms to various 16-membered ring MLs tested. These differences in proportions of resistant organisms to different MLs may have resulted from differences in resistance induction activities of different MLs. The above described ratios of resistant organisms to MLs among S. aureus did not vary since 1975 among clinical isolates tested in our laboratory. 2. Four per cent (4%) of Streptococcus pyogenes isolates were MLs resistant, and 18% of Streptococcus pneumoniae isolates were resistant to MLs. Among the isolates tested in our laboratory since 1985, resistant isolates of S. pyogenes are clearly decreasing and those of S. pneumoniae seem to be increasing.(ABSTRACT TRUNCATED AT 250 WORDS)

Anti-Bacterial Agents↗

PubMed1990

[Antimicrobial activities of gentamicin against fresh clinical isolates].

Antimicrobial activities of gentamicin (GM), compared with activities of other aminoglycosides (AGs) and beta-lactam antibiotics, were studied against clinical isolates obtained during a period of July-December 1989. 1. GM-resistant strains were noted in 24% of Staphylococcus aureus, 12% of Enterobacter spp., 24% of Serratia marcescens, 7% of Morganella morganii and 26% of Pseudomonas aeruginosa, but no GM-resistant strains were observed among isolates of Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis and Proteus vulgaris. 2. A majority of GM-resistant strains of S. aureus were methicillin-resistant S. aureus (MRSA) and a large number of GM-resistant strains of Enterobacter spp. was also resistant to new quinolones. GM showed, however, strong antimicrobial activities against new quinolones-resistant strains of S. marcescens, M. morganii and P. aeruginosa. 3. Among all the isolates tested of S. marcescens, 24% were GM-resistant, 72% were tobramycin (TOB)-resistant, 86% were dibekacin (DKB)-resistant and 64% were amikacin (AMK)-resistant, hence the incidence of GM-resistant strains was the lowest. This tendency was also observed with P. vulgaris. However, among P. aeruginosa, 26% were GM-resistant, 14% TOB-resistant, 18% DKB-resistant and 22% AMK-resistant, thus the incidence rate for GM-resistance was somewhat higher. These results suggest that different AGs-modification enzymes were produced by various clinical isolates under the present condition. 4. Comparing the ratio of GM-resistant strains in the present study with those in 1980 and 1983, the ratio increased among S. aureus, while decreases were observed among Enterobacter spp., S. marcescens, P. vulgaris and P. aeruginosa, indicating that a unilateral tendency of increases in GM-resistant strains did not exist among clinical isolates over the years.

Anti-Bacterial Agents↗

PubMed1990

[Synergy between sulbactam and ampicillin or cefoperazone in antimicrobial activity against beta-lactamase producing microorganisms. Results with the use of microdilution broth method].

Antimicrobial activities of sulbactam (SBT) with ampicillin (ABPC) or with cefoperazone (CPZ), in other words, the effects of SBT, an beta-lactamase inhibitor, against beta-lactamase producing strains of clinical isolates, were studied using microdilution broth method. 1. beta-Lactamase producing strains such as Staphylococcus aureus, Branhamella catarrhalis, Haemophilus influenzae, Escherichia coli and Klebsiella pneumoniae decompose benzylpenicillin (PCG) which is one of substrates of the acid-metry disc method and show a strong reaction, while they do not decompose cefazolin (CEZ), another substrate, showing no or weak reaction. Thus, it is suspected that beta-lactamases produced by these organisms are mainly penicillinase (PCase). MIC-distributions of ABPC and CPZ against these clinical isolates which seemed to produce PCase shifted to lower MIC ranges with MIC's reduced to 1/4 or below when 0.025 to 0.39 microgram/ml of SBT was added. 2. It appears that beta-lactamase produced by Proteus vulgaris may be oxyiminocephalosporinase (CXase), because P. vulgaris showed strong reaction on CEZ, but moderate reaction on PCG in the acid-metry disc method. MIC-distribution of ABPC and CPZ against P. vulgaris shifted to a lower range with MIC's of 1/4 or below when 0.20 to 0.39 microgram/ml of SBT was added. 3. All the test strains of Pseudomonas aeruginosa showed strong reaction on CEZ but only 56% of the test strains showed reaction on PCG. It appears that the beta-lactamases which showed strong reaction on CEZ is cephalosporinase and is encoded in chromosome, while those beta-lactamase that showed strong reaction on PCG is encoded in a plasmid which was acquired secondarily by P. aeruginosa. MIC-distribution of CPZ against P. aeruginosa shifted to a lower range with MIC values of 1/2 or below with the addition of SBT at 1.56 micrograms/ml. 4. It appears that the synergy of SBT with ABPC or with CPZ against the PCase or CXase producing strains may occur in the presence of SBT at a concentration far less than that reported previously.

Ampicillin↗

PubMed1990

[Annual changes in susceptibility of clinical isolates to midecamycin acetate].

To investigate annual changes in the susceptibility of clinical isolates to midecamycin acetate (MDM-AC), minimum inhibitory concentrations (MICs) of MDM-AC were determined for clinical isolates obtained from outpatients since 1985. MDM-AC-resistant strains of Staphylococcus spp. and Streptococcus spp. have shown similar degrees of resistance to midecamycin and josamycin. Regarding this as macrolide resistance, proportions of macrolide-resistant strains tended to increase for Staphylococcus aureus and Streptococcus pneumoniae but to decrease for Streptococcus pyogenes. 1. For S. aureus, 8% of the strains isolated in 1985, 20% in 1987 and 20% in 1989 were macrolide-resistant. Of these macrolide-resistant strains, 70% or more in 1987 and 80% or more in 1989 were methicillin-resistant S. aureus (MRSA). 2. For S. pneumoniae, 8% of the strains isolated in 1985, 12% in 1987 and 12% in 1989 were macrolide-resistant, indicating a tendency for resistant strains to increase annually. 3. For S. pyogenes, 8% of the strains isolated in 1985, 4% in 1987 and 0% in 1989 were macrolide-resistant, showing a decreasing tendency. 4. MDM-AC is still thought to be a clinically useful antibacterial agent because it still shows antibacterial activity against 80% or more of Gram-positive cocci clinically isolated in recent years and a low degree of induction of macrolide resistance in Staphylococcus spp.

Bacterial Infections↗

PubMed1990

[Measurement of MICs on 16 antimicrobial agents for freshly isolated methicillin-resistant Staphylococcus aureus strains].

MICs of 16 antimicrobial agents including a newly synthesized aminoglycoside antibiotic, arbekacin (HBK), were determined against methicillin-resistant Staphylococcus aureus (MRSA) strains which had been isolated since 1988 from patients with refractory infections. 1. The proportion of highly methicillin-resistant strains was large, especially among those isolated from blood and respiratory tract. 2. All the MRSA strains were resistant to all the beta-lactam antibiotics tested. 3. Most of the strains were also resistant to aminoglycosides. However, HBK inhibited the growth of 95% of the strains at 3.13 micrograms/ml or less, showing potent activities even against highly resistant MRSA strains. 4. The MIC distribution of HBK against MRSA strains showed no change since 1986 when year to year data were compared. Based on our studies on the drug resistance pattern of MRSA since 1986, a large proportion of MRSA strains isolated from blood and respiratory tract appeared to be coagulase type II. 5. Netilmicin-resistant MRSAs have increased since 1986, and MRSA resistant to fosfomycin, minocycline, ofloxacin and norfloxacin have also increased in 1989 compared to 1988. 6. The drug resistance pattern of MRSA has been changing every year and they are acquiring multi-drug resistance. Thus, in the treatment of MRSA infections, it is very important to identify the drug susceptibility of MRSA quickly and accurately.

Aminoglycosides↗

PubMed1989

[Determination of the MIC of cefotetan against freshly isolated gram-negative bacilli].

Antimicrobial activities (MICs) of cefotetan (CTT) against 575 strains of 16 spp. of Gram-negative bacilli isolated in 1988 were determined to investigate distribution of MICs in comparison with those of cefmetazole (CMZ), cefoxitin (CFX), latamoxef (LMOX) and cefazolin (CEZ). The change in frequencies of incidence of cephem-resistant strains in the latter half of the 1980 was also investigated. Distribution of MIC of CTT varied with test strains. No or very few MICs were at or higher than 12.5 micrograms/ml at an inoculation of 10(6) cfu/ml, thus rates of CTT-resistant strains were low among Escherichia coli, Citrobacter diversus, Klebsiella spp., Proteus spp., Providencia spp., and Haemophilus influenzae. High rates of resistance to CTT were observed, however, among Citrobacter freundii, Enterobacter spp., Serratia marcescens, Morganella morganii, and Bacteroides fragilis. 2. Most CTT-resistant strains of C. freundii, Enterobacter spp. and S. marcescens were also resistant to LMOX. These resistant strains were considered to be multi-resistant strains to antibiotics including oxime type cephalosporins and monobactams. 3. Cephem-resistant E. coli was confirmed to be resistant to 22% of CEZ, 14% of CFX, 10% of CMZ and 2% of CTT tested. The incidence of cephem-resistant E. coli unconditionally showed an increasing tendency. 4. The incidence of resistant strains against cephamycins including CTT is discussed with regard to the mechanism of resistance against all beta-lactam antibiotics, and the problem of the appearance of resistant strains is close and inseparable from social background.

Cefazolin↗

PubMed1989

[Treatment of female acute cystitis with a single dose of cefminox].

Thirty six female patients with acute cystitis were treated with one shot intravenous injection of 1 g cefminox. Clinical efficacy was evaluated based on extent of subjective symptoms, pyuria and bacteriuria. Of 36 patients, an excellent efficacy was shown in 32 cases, moderate in 3 cases and poor in 1 case. This poor case was diagnosed as complicated urinary tract infection because of right vesicoureteral reflux. Therefore, the overall effectiveness rate of this treatment for acute uncomplicated cystitis in women was 100%. Single dose chemotherapy with an adequate antibiotic is considered a useful treatment for female acute cystitis.

Acute Disease↗

PubMed1989

[Antimicrobial activity of cefteram comparison with other oral antibiotics].

Antimicrobacterial activities of cefteram (CFTM) against clinical isolates collected in 1988 were compared with those of new beta-lactams. 1. Antibacterial activities of CFTM against Streptococcus pneumoniae, Streptococcus pyogenes, Haemophilus influenzae, Branhamella catarrhalis isolated from acute respiratory tract infections were 8- to 16-fold higher than those of cefaclor (CCL). 2. Activities of cefixime (CFIX) were superior to those of CFTM against B. catarrhalis, Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, but were inferior to CFTM against S. pneumoniae, S. pyogenes, Staphylococcus saprophyticus and Staphylococcus aureus. 3. Activities of cefuroxime were superior to those of CCL against each of the 4 tested bacterial species from acute respiratory tract infection and S. aureus by 4-fold, but were inferior to CFTM and CFIX against most of Gram-negative rods. 4. Sultamicillin (SBTPC) is considered to have an activity to inhibit beta-lactamase, but its MICs did not exceed the MICs of ampicillin by itself. SBTPC showed poor antibacterial activities against methicillin-resistant S. aureus (MRSA). Considering these observations, it is apparent that we are faced with a variety of factors in selecting antibiotics for best results.

Ampicillin↗

PubMed1988

[Antibacterial activities of monobactams against fresh clinical isolates].

Antibacterial activities of monobactam antibiotics (carumonam (CRMN) and aztreonam (AZT] against Gram-negative bacilli isolated from inpatients in the latter half of 1987 were investigated using penicillin (PC: piperacillin (PIPC], cephems (CEPs: ceftazidime (CAZ), cefotaxime (CTX), latamoxef (LMOX), cefsulodin (CFS], carbapenem (imipenem (IPM] and pyridonecarboxylic acids (norfloxacin (NFLX) and ofloxacin (OFLX] as reference antibiotics. A total of 400 strains of 13 species, i.e. Escherichia coli, Klebsiella pneumoniae, Klebsiella oxytoca, Proteus mirabilis, Proteus vulgaris, Morganella morganii, Providencia rettgeri, Citrobacter freundii, Enterobacter cloacae, Enterobacter aerogenes, Serratia marcescens, Pseudomonas aeruginosa and Haemophilus influenzae, were used as test strains. 1. CRMN and AZT, both monobactam antibiotics, were roughly comparable in their activities and no resistant strain to these antibiotics were found among isolates of E. coli, Klebsiella spp., Proteus spp., M. morganii, P. rettgeri or H. influenzae and few resistant strains were observed among isolates of S. marcescens. On the other hand, isolates of C. freundii, Enterobacter spp. and P. aeruginosa included rather numerous strains resistant to the monobactam antibiotics. Among these cases, whereas R strains, i.e. resistant strains showing MICs greater than or equal to 50 micrograms/ml, accounted for a large proportion of strains resistant to PC and CEPs, I strains, i.e. intermediately resistant strains showing MICs between 12.5 and 25 micrograms/ml, accounted for a large proportion of strains resistant to the monobactam antibiotics. 2. Strains resistant to PIPC, a PC, were detected with high and more or less uniform frequencies over the entire spectrum of the isolates examined. 3. Antibacterial activities of CEPs varied against different bacterial species. While strains resistant to CTX, CAZ and LMOX were commonly detected with high frequencies among isolates of C. freundii, Enterobacter spp. and S. marcescens, large percentages of LMOX-resistant strains of C. freundii and Enterobacter spp. were of the I type. CTX-resistant strains were also found among isolates of P. vulgaris and M. morganii. Proportions of CEP-resistant strains of P. aeruginosa were 28% for CFS and 12% for CAZ. 4. No or few strains among the isolates of 13 species investigated were resistant to IPM, a carbapenem antibiotic, which showed the most stable antibacterial activity, but it was less active than monobactam antibiotics and CEPs against Klebsiella spp., P. mirabilis and H. influenzae.(ABSTRACT TRUNCATED AT 400 WORDS)

4-Quinolones↗

PubMed1988

[Antibacterial activity of gentamicin against clinical isolates in pediatrics].

Antibacterial activity of gentamicin (GM), along with activities of other aminoglycosides and beta-lactams, was studied against clinical isolates collected from pediatric patients during a period of May 1986-April 1987. 1. GM-resistance was noted in 22% of Staphylococcus aureus, 6% of Proteus vulgaris, 8% of Morganella morganii, 40% of Providencia spp., 6% of Enterobacter spp., 14% of Serratia marcescens, and 14% of Pseudomonas aeruginosa isolates. No GM-resistance was observed with isolates of Escherichia coli, Klebsiella pneumoniae and Proteus mirabilis. 2. The antibacterial activity of GM against clinical isolates from pediatric patients was found to be comparable to its activity against clinical isolates from adults studied at the same time. 3. The majority of GM-resistant strains of S. aureus were MCRSA, and the GM-resistant strains of S. marcescens and P. aeruginosa were found also to be resistant to multiple drugs. 4. GM-resistant strains were found at relatively high rates (14-22%) in S. aureus, S. marcescens and P. aeruginosa. These rates did not increase compared to the rates observed in the first half of the 1980's. 5. GM was considered to have poor antibacterial activity against genus Providencia. It is concluded from above results that GM still maintains effective antibacterial activity against many of causative organisms of infections in both adults and children.

Anti-Bacterial Agents↗

PubMed1988

[Antimicrobial activities of sultamicillin against clinical isolates from upper respiratory tract infections].

Sultamicillin (SBTPC) is a mutual prodrug in which ampicillin (ABPC) and a potent beta-lactamase inhibitor sulbactam (SBT) are ester-bound in an equimolar ratio. SBTPC is hydrolyzed during absorption after oral administration to provide ABPC and SBT for systemic circulation. In the present study, the antimicrobial activities of SBTPC against 50 isolates each of 6 species (Staphylococcus aureus, Klebsiella pneumoniae subsp. pneumoniae, Branhamella catarrhalis, Haemophilus influenzae, Streptococcus pneumoniae and Streptococcus pyogenes) of bacteria freshly obtained from upper respiratory tract infections were examined in relation to their bacterial beta-lactamase producing abilities. beta-Lactamase producing strains were identified using the acidometry disc method with benzylpenicillin (PCG) of cefazolin (CEZ) as a substrate, and their frequencies of appearance were calculated as follows: S. aureus 86%; K. pneumoniae subsp. pneumoniae 100%; B. catarrhalis 68%; H. influenzae 24%. Fourteen per cent of S. aureus strains examined were beta-lactamase positive using both PCG and CEZ acidometry discs. SBTPC, however, demonstrated excellent antimicrobial activities even against these beta-lactamase producing strains. Good activities were observed especially against those bacterial strains producing penicillinase (PCase). Average MIC80 values of SBTPC were 3.13 micrograms/ml for S. aureus and K. pneumoniae subsp. pneumoniae, 0.39 micrograms/ml for B. catarrhalis and H. influenzae, 0.05 micrograms/ml for S. pneumoniae and 0.025 micrograms/ml for S. pyogenes. As SBTPC was shown to possess excellent antimicrobial activities against PCase producing strains, the enhancement in activities of SBTPC compared to ABPC alone can be attributed to the inhibition of beta-lactamase by SBT which, as noted above, is a component of SBTPC in an equimolar ratio to ABPC.

Acute Disease↗

PubMed1988

[Antimicrobial activity of sultamicillin against clinical isolates from upper respiratory tract infections II].

In an attempt to examine the effect of sulbactam (SBT) on beta-lactamase activity, three hundred clinical isolates from the infected upper respiratory tract were tested for MICs and disk sensitivities of ampicillin (ABPC) and sultamicillin (SBTPC). beta-lactamase production was tested using the acidometry disk method (beta-Check, Taito Pfizer Co.). For strains such as Klebsiella spp. which form mucoid type colonies, we used the SS culture medium which, by reducing the influence of huge amounts of capsular material, allows a better reaction to the acidometry disk. Penicillinase, produced by Branhamella catarrhalis, Haemophilus influenzae, Neisseria spp., etc. was detected clearly by direct application of portions of colonies onto acidometry disks. For cephalosporinase, however, a direct application of such fractions resulted in weak reactions. We, therefore, used fractions which had undergone the enzyme induction, and obtained better reactions. Sensitivities of tested bacteria to ABPC and SBTPC were inversely related to MIC values. beta-Lactamase-producing strains showed weaker sensitivity to ABPC than non-producing strains. To SBTPC, however, beta-lactamase-producing strains and non-producing strains showed very similar sensitivity. We thus confirmed that the inhibitory action of SBT to beta-lactamase can well be demonstrated using the disk sensitivity method.

Ampicillin↗

PubMed1988

[Metastatic tumor of the spermatic cord from renal cell carcinoma].

The patient was a 54-year-old man with a hard nodule (25 x 15 mm) in his left scrotum. His left spermatic vein had been ligated 6 months earlier because of a varicocele. Preoperative diagnosis was left renal tumor with multiple lung metastasis. The intrascrotal nodule was considered to be a metastatic tumor from renal cell carcinoma. Left nephrectomy was performed and the metastatic lesion of spermatic cord was also removed. Pathological examination showed that the left renal tumor was renal cell carcinoma (clear cell type). The spermatic cord nodule was tumor embolus in dilated veins and consisted of the same clear cells as renal cell carcinoma. Judging from these results, in this case renal cell carcinoma retrogradely metastasized through the spermatic vein to the intrascrotal lesion.

Carcinoma, Renal Cell↗

PubMed1987

[The antimicrobial activity of sisomicin against fresh clinical isolates].

Antimicrobial activities of sisomicin (SISO) against clinical isolates obtained in the second half of 1986 were investigated together with other 4 aminoglycosides (AGs) (gentamicin (GM), tobramycin (TOB), dibekacin (DKB), amikacin (AMK] and 2 cephems (cefotiam, cefotaxime), and were compared to the results reported in the period of late 1970's through early 1980's in Japan. 1. The incidence of SISO-resistant Staphylococcus aureus in the present study was 18% and is comparable to that of the other studies suggesting that the incidence of SISO resistant strains remains on the stable level. The incidence of SISO-resistant Pseudomonas aeruginosa showed the tendency of slight increase. 2. SISO-resistant strains of Enterobacter spp., Serratia marcescens and Citrobacter freundii did not show increase from the 1970/1980 levels. 3. Isolation rates of SISO-resistant indole(+) Proteus varied depending on strains. Isolation rates of SISO-resistant P. vulgaris and Morganella morganii were both as low as 4%, but that of Providencia rettgeri was as high as 60%. Refering to an American study reporting that the Genus Providencia including P. rettgeri showed high incidence of resistance to SISO as well as to GM or TOB, we pointed out that the antimicrobial activity of AGs against Genus Providencia should be evaluated separately from those of other indole(+) Proteus strains. 4. No SISO-resistant strains of Escherichia coli, Klebsiella pneumoniae or P. mirabilis were found. 5. SISO had good antimicrobial activity against most of the investigated species and SISO may still be regarded as one of the clinically useful AGs.

Bacterial Infections↗

PubMed1987

[Antimicrobial activity of sulbactam/cefoperazone. Comparison with other new cephems].

Antimicrobial activities of sulbactam/cefoperazone (SBT/CPZ) against 50 fresh clinical isolates of Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Citrobacter freundii, Enterobacter spp., Serratia marcescens, Proteus mirabilis, Proteus vulgaris and Pseudomonas aeruginosa were compared to those of CPZ, Cefotiam (CTM), Cefotaxime (CTX) and Latamoxef (LMOX). Minimal inhibitory concentrations (MIC's) of SBT and CPZ mixed in a ratio of 1:1 were determined by the dilution method using Mueller-Hinton agar and expressed by absolute concentrations of CPZ. Antimicrobial activities of SBT/CPZ against principally penicillinase (PCase) producing bacteria, i.e., S. aureus, E. coli, K. pneumoniae, P. mirabilis, were superior to those of CPZ alone. The presence of SBT in concentrations around 0.39 approximately 1.56 micrograms/ml clearly enhanced CPZ's antimicrobial activities against these PCase producing strains. The synergistic antimicrobial effects of SBT in combination with CPZ were less pronounced against principally cephalosporinase (CEPase) producing bacteria, i.e., C. freundii, Enterobacter spp., S. marcescens, P. vulgaris, and P. aeruginosa, and exerted with SBT at concentrations around 3.13 approximately 12.5 micrograms/ml. Comparative antimicrobial activities indicated by MIC80's of tested agents showed that SBT/CPZ had more stable activities against bacteria ranging from Gram-positive to Gram-negative bacteria than CTM, CTX and LMOX. MIC's of SBT/CPZ were higher than 25 micrograms/ml against 8% of S. aureus, 18% of C. freundii, 10% of Enterobacter spp., 26% of S. marcescens, 2% of P. vulgaris, and 18% of P. aeruginosa. These resistant strains against which the addition of SBT showed no synergism, may possess other mechanism of resistance than beta-lactamase production. It is concluded that the presence of CPZ resistant strains is an actual current problem and not an imaginary future problem, and that the number of resistant strains against other new cephems which have different chemical structure from CPZ is increasing. When these present bacteriological environments are considered, the appearance of SBT/CPZ in the clinical practice is timely and meaningful.

Bacteria↗

PubMed1987

[Antibacterial activities of various aminoglycosides against clinically isolated methicillin-resistant Staphylococcus aureus].

Methicillin-resistant Staphylococcus aureus (MRSA) were isolated from samples collected from various patients during 1986, and antibacterial activities of 6 aminoglycosides (AGs) (netilmicin (NTL), gentamicin (GM), sisomicin (SISO), dibekacin (DKB), tobramycin (TOB) and amikacin (AMK] and 4 beta-lactam antibiotics (cefazolin (CEZ), cefmetazole (CMZ), cloxacillin (MCIPC) and methicillin (DMPPC) against these MRSA were evaluated. Among these 6 AGs, NTL was the most potent, and its MIC50 and MIC80 were 1.56 and 3.13 micrograms/ml, respectively. Antibacterial activities of GM, SISO, DKB and TOB were weak, and MIC50's of GM and DKB were both 100 micrograms/ml, while those of SISO and TOB were 50 and greater than 100 micrograms/ml, respectively. Frequency of highly resistant specimens to AMK was rather low and its MIC50 and MIC80 were 12.5 and 25 micrograms/ml, respectively. As for antibacterial activities of the above 4 beta-lactam antibiotics, the MIC50 and MIC80 of CMZ were 6.25 and 12.5 micrograms/ml, respectively, and therefore, its antibacterial activity to MRSA is relatively good. However, MIC50's of CEZ, MCIPC and DMPPC were all greater than 100 micrograms/ml, showing poor antibacterial activities. Recently, MRSA became a problem in various fields of clinical practice, and a number of literatures reporting refractory infections caused by MRSA have been published. Since MRSA is featured as multiply resistant bacteria, it is known that MRSA is resistant to the majority of existing antibiotics (penicillins, cephems, macrolides, AGs, etc.). In 1985, we reported results of our study concerning the antibacterial activities of a number of CEPs and some of AGs against multiply resistant S. aureus including MRSA.(ABSTRACT TRUNCATED AT 250 WORDS)

Amikacin↗