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Volume 52, Issue 8
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KUNIMOTO HOTTA, JUN ISHIKAWA, RYOICHI ISHII, FUMIKO SAITOH, KIYOKO KIR ...1999 Volume 52 Issue 8 Pages 525-532
Published: August 25, 1999
Released on J-STAGE: May 17, 2013
JOURNAL FREE ACCESSArbekacin (ABK)-resistant bacteria (43 strains) isolated as MRSA by regular clinical procedures in Japanese clinics in 1998 were characterized in terms of taxonomic properties, aminoglycoside resistance, andrnec A and aac(6´)/aph(2´ ´) genes linking with ABK-resistant MRSA. Taxonomically the 43 strains fell intoStaphylococcus aureus(33 strains) and Enterococcus (10 strains). As to ABK resistance, the 13 strains of MRSA clinically reported as high ABK resistants (128μg/ml or higher) did not show clear high ABK resistance except for 2 strains when their ABK resitance was tested using 0.5% NaCl containing nutrient agar.We designed and established the primers and conditions for PCR to detect the above two resistance genes. PCR analysis of DNAs from the 43 strains clearly indicated that only 33 strains identified taxonomically as S. aureuspossessesd mecA indicating MRSA and 23 out of them possessed aac (6´)/aph (2´ ´). The other 10 strains of MRSA lacking aac (6´)/aph(2´ ´) were ABK-sensitive. Thus, there were a good correlation between ABK resistance andaac(6´)/aph(2´´) existence.
Based on these, it was conclusive that the appropriate ABK resistance test as well as the detection of mecA andaac(6´)/aph(2´ ´) genes by PCR are necessary and useful to avoid false ABK-resistant MRSA strains.View full abstractDownload PDF (2458K) -
HARUMI KAWADA, AKIKO KITAYAMA, TAKASHI FUKUOKA, CHIKA ISHII, TOMOMI AB ...1999 Volume 52 Issue 8 Pages 533-540
Published: August 25, 1999
Released on J-STAGE: May 17, 2013
JOURNAL FREE ACCESSWe evaluated in vitro and in vivo activities of cefpodoxime proxetil (CPDX-PR) in comparison with otheroral β-lactams, cefdinir (CFDN), cefditoren pivoxil (CDTR-PI), and faropenem (FRPM), against penicillin-susceptibleand -resistant Streptococcus pneumoniae.
In vitro activities (MICs) of CPDX, CFDN, CDTR, and FRPM against clinical isolates, penicillin-susceptibleS. pneumoniae(PSSP: MIC of penicillin G, ≤0.063μg/ml), penicillin-intermediate S. pneumoniae(PISP: MIC of penicillin G, 0.125-1μg/ml), and penicillin-resistant S. pneumoniae(PRSP: MIC of penicillin G, ≥2μg/ml), were tested by an agar dilution method. The MIC80s of CPDX against 27 PSSP strains, 23 PISP strains, and 23 PRSP strains were 0.032, 1, and 8μg/ml, respectively, which were superior to or equal to those of CFDN (0.063, 4, and 8μg/ml) and were inferior to those of CDTR (0.016, 0.5, and 1μg/ml) and FRPM (≤0.008, 0.25, and 1μg/ml).
Infection was induced in mice by inoculating with a PRSP clinical isolate, 9605 or 9601 (serotype 6), or10692 (serotype 19), through the nares of male ddY mice into the lungs. The mice were treated with drugs withdoses of 2-50 mg/kg at 18, 26, 42, and 50 hours after the infection. Viable cell numbers in the lungs and bloodwere assayed at 66 hours after the infection. The efficacy of each drug was dose-dependent. CPDX-PR showedthe most potent in vivo efficacy among the drugs tested against the infections caused by the PRSP strains. MICsof the drugs against PRSP 9605, 9601, and 10692 were as follows: CPDX, 4, 4 and 2μg/ml; CFDN, 16, 16, and4μg/ml; CDTR, 1, 1, and 0.5μg/ml; and FRPM, 1, 0.5, and 0.5μg/ml, respectively. Thus, CPDX-PR showed astronger in vivo activity than that expected from the MICs of CPDX. This was probably caused by the pharmacokinetic advantage of CPDX over the other drugs used in this study.View full abstractDownload PDF (962K) -
TAKAAKI NASU, KIYOMI OKAMOTO, TOSHIHIRO NAKANISHI, TAKESHI NISHINO1999 Volume 52 Issue 8 Pages 541-553
Published: August 25, 1999
Released on J-STAGE: May 17, 2013
JOURNAL FREE ACCESSAgainst enterohemorrhagic Escherichia coli (EHEC) O157 clinically isolated, the effects of faropenema novel oral penem antibiotic, on the MICs, bactericidal activity, verotoxin (VT)-release, andlipopolysaccharide (LPS)-release were investigated IN VITRO and compared with those of other types of antibacterialagents.
The MICs of FRPM in aerobic and anaerobic culture condition, were 0.78 and 0.39μg/ml, respectively. In aerobic condition, FRPM was more active than ampicillin, amoxicillin (AMPC), fosfomycin (FOM), kanamycin (KM), minocycline (MINO), and clarithromycin (CAM), but was slightly less active than cefdinir (CFDN), cefditoren (CDTR), and norfloxacin (NFLX) against 0157 clinical isolates. In anaerobic condition, however, FRPM showed as strong activity as CFDN, CDTR, and NFLX.
FOM, NFLX, and KM as well as the β-lactams including FRPM indicated the powerful bactericidal activityagainst one strain of 0157 clinical isolates. The effects of MINO and CAM were bacteriostatic.
FOM and the β-lactams including FRPM promoted verotoxin type 1 (VT1)-release, but rather suppressedverotoxin type 2 (VT2)-release from the same isolate. NFLX, however, promoted VT 1-release and vast amountof VT2-release. In the case of KM, MINO, and CAM, the release suppression of both VT1 and VT2 wasobserved.
FRPM, AMPC, and FOM had very weak activity on LPS-release, while CFDN, CDTR, and NFLX releaseda large amount of LPS from the strain. KM, MINO, and CAM had relatively weak activity.
In these IN VITRO experiments, FRPM demonstrated the effective profile to the treatment for EHEC infection, except for the effect on VT1-release. These results suggest the possibility that FRPM shows good clinical efficacy for EHEC infection.View full abstractDownload PDF (1511K) -
KAZUTAKA ENDO1999 Volume 52 Issue 8 Pages 554-561
Published: August 25, 1999
Released on J-STAGE: May 17, 2013
JOURNAL FREE ACCESSThe neuromuscular blocking properties of aminoglycoside group of antibiotics arbekacin sulfate (ABK), astromicin sulfate (ASTM), isepamicin sulfate (ISP), netilmicin sulfate (NTL) and d-tubocurarine were studied in30 rabbits anesthetized with pentobarbital. The left gastrocnemius tendon was cut and secured to a force-displacementtransducer. The left tibial nerve was directly stimulated by electrodes with supramaximal squarewaves of 0.1 msec duration at a frequency of 0.1 Hz. The resultant force of twitch tension was recorded.
The intravenous administration of ABK 60-100mg/kg, ASTM 160-320mg/kg, ISP 320-480 mg/kg or NTL 20-40mg/kg resulted in dose-dependent decreases in twitch tensions. The ED50values of 4 antibioticswere NTL=30.2mg/kg (4.2×10-2mmol/kg) <ABK=78.3mg/kg (1.4×10-1mmol/kg)<ASTM=215.2mg/kg (3.6×10-1mmol/kg) <ISP=359.7mg/kg (6.3×10-1mmol/kg), respectively. These antibiotics-induced blockadeswere antagonized by calcium or by neostigmine.
Although the relative neuromuscular blocking potencies of 4 antibiotics equipotent to d-tubocurarine on thebasis of therapeutic doses in man were below 0.6 mg, it may be concluded that the potential clinical hazard lies in the sequence of administration of the aminoglycoside group of antibiotics.View full abstractDownload PDF (1096K)
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