摘要:

Two of the 3rd generation cephalosporins, ceftriaxone and cefotaxime, have an almost identical antibacterial spectrum, but completely different pharmacokinetics. After an intravenous dose of 1 g, peak levels of both cephalosporins were > 100 μg/ml. Cefotaxime levels fall rapidly with a T½ of 1.1 h, whereas ceftriaxone persists for 24 h with an unique T½ of 8 h. Cefotaxime is eliminated by the kidneys and metabolized to desacetyl-cefotaxime resulting in a high total clearance. In contrast, ceftriaxone is not metabolized and highly protein bound with a total clearance of only 14 ml/min. Peak concentrations of antibiotics are lower in extravascular compartments than in serum. They depend on the dose administered and the serum T½; they are lower with highly bound drugs. Concentrations of ceftriaxone and cefotaxime were measured by Andrews and Wise in blister fluids, in ascites and pleural fluid by us. We found concentrations of 20–26 μg/ml ceftriaxone up to 12 h in ascites, but only 7–15 μg/ml cefotaxime. The levels persisted for 24 h for ceftriaxone, whereas they fell rapidly for cefotaxime. Because the minimum inhibition concentrations increase in the presence of proteins, and because free, unbound, microbiologically active ceftriaxone is lower than the measured total antibiotic concentrations, we suggest that 2-gram doses should be administered – at least at the beginning of the treatment of an infectious disease – and fo

ISSN:0009-3157    

DOI:10.1159/000238319

出版商:S. Karger AG    

年代:1985

数据来源: Karger

摘要:

The suitability of a very sensitive modification of the clover-leaf test as a test for inactivation of β-lactam antibiotics by gram-negative rods was examined. 143 Enterobacteriaceae and 9 strains of Pseudomonasaeruginosa were examined by the clover-leaf test and an antibiotic susceptibility test towards 12 β-lactam antibiotics. The β-lactamase activity of the strains was also examined by a sensitive modification of the chromogenic cephalosporin test. The strains of P. aeruginosa could not be clover-leaf tested as they inhibited the indicator strains. All the Enterobacteriaceae which had β-lactamase activity according to the chromogenic test inactivated at least 1 of the antibiotics in the clover-leaf test. None of the Enterobacteriaceae without β-lactamase activity inactivated any of the antibiotics. On the whole the results of the clover-leaf test and the results of the susceptibility test correlated well. But many Enterobacteriaceae were susceptible to an antibiotic in the susceptibility test even though they inactivated it according to the clover-leaf test and some Enterobacteriaceae were resistant to an antibiotic but did not inactivate it. Among the Enterobacteriaceae which had β-lactamase activity according to the chromogenic cephalosporin test and which were intermediately susceptible to an antibiotic in the susceptibility test, many did not inactivate this antibiotic according to the clover-leaf test. If an infection with Enterobacteriaceae has to be treated by a β-lactam antibiotic to which the strain is only intermediately susceptible, it might be advantageous to use an antibiotic which is not inactivated by the strain according to the clover-leaf test, but this lacks clinical confir

ISSN:0009-3157    

DOI:10.1159/000238320

出版商:S. Karger AG    

年代:1985

数据来源: Karger

摘要:

The in vitro effect of latamoxef against 50 clinical strains of Pseudomonas aeruginosa was compared to that of ticarcillin, both alone and in combination with the aminoglycosides gentamicin, tobramycin and amikacin. Alone, the MIC90 of latamoxef was consistently one-half the MIC90 of ticarcillin. The two antibiotics appeared similar in regard to inoculum effect and bacterial killing. Adding of one-quarter the minimum inhibitory concentration of the aminoglycoside antibiotic to the beta lactam caused reduction in MIC90 of the latter (either ticarcillin or latamoxef) by one-half and decreased the MIC50 by almost one-quarter the concentration required by the beta lactams singly. Therefore, latamoxef singly or in combination with aminoglycosides behaved similarly but was more active than ticarcillin. Using combinations of antibiotics likely to be achieved in the serum of patients, a beneficial in vitro effect (either additive, partially synergistic or synergistic) generally occurred for the beta lactam-aminoglycoside combination if the strain was relatively sensitive to the aminoglycoside used in this combination. It occurred much less frequently for the highly aminoglycoside-resistant isolates.

ISSN:0009-3157    

DOI:10.1159/000238321

出版商:S. Karger AG    

年代:1985

数据来源: Karger

摘要:

302 clinical isolates representing 16 bacterial species most often implicated in ocular infections were tested in vitro against norfloxacin and a panel of antibacterial agents. On the basis of the 90% minimal inhibitory concentration (MIC90) data, norfloxacin was 4–32 times more active than the next best antimicrobial tested against Citrobac-ter freundii, Escherichia coli, Morganellamorganii, Proteus mirabilis, Proteus vulgaris, Haemophilus influenzae, Neisseria gonorrhoeae and Staphylococcus epidermidis, with overall MlC90 < 1 mg/1. Norfloxacin was equal in activity to polymyxin B against Klebsiella pneumoniae (MIC90 = 1 mg/1), and it ranked second to both polymyxin B against Pseudomonas aeruginosa and cotrimoxazole against Staphylococcus aureus, (MIC90 = 2 mg/1 in each case). Along with neomycin and cotrimoxazole, norfloxacin (MIC90 = 1 mg/1) ranked second to gentamicin and tetracycline against Moraxella species. Compared to erythromycin (MIC90 < 0.125 mg/1), norfloxacin (MIC90 < l6 mg/1) was considerably less active against streptococci. Overall, norfloxacin was the most active agent in both potency and antibacterial spectrum against the test organisms. These results suggest the potential use of norfloxacin in the treatment of superficial bacterial infections of the ey

ISSN:0009-3157    

DOI:10.1159/000238322

出版商:S. Karger AG    

年代:1985

数据来源: Karger

摘要:

30 representative intrinsically penicillin-resistant coagulase-negative staphylococcal (CONS) isolates yielded discrepant agar disk diffusion test (Bauer-Kirby) results for augmentin. Clavulanic acid (2.5 μg/ml) enhanced the activity of amoxycillin from 8- to > 128-fold (x = 26-fold); MICs of amoxycillin (combined with 2.5 μg/ml clavulanate) ranged from 1–16 (X = 3) μg/ml. It is recommended that clinical microbiology laboratories withhold ‘susceptible’ augmentin disk tests results from their reports regarding intrinsically penicillin-resistant CONS isolates. No such discrepancies were encountered among clinical isolates of Staphylococcus au

ISSN:0009-3157    

DOI:10.1159/000238323

出版商:S. Karger AG    

年代:1985

数据来源: Karger

摘要:

The combination of subinhibitory concentrations of trimethoprim (Tp) and nitrofurantoin (NT) seemed additively inhibitory against sensitive Escherichia coli K12, chromosomally mediated NT, R-plasmid mediated Tp and NT-resistant E. coli strains, respectively. The minimal inhibitory concentrations of 6 μg/NT/ml and 2 μg Tp/ml against the sensitive strain were respectively reduced 5-fold by a minimum inhibitory combination of Tp + NT. The 30-fold chromosomally mediated and 15-fold R-plasmid NT resistance were 3- and 5-fold respectively reduced by a minimum inhibitory combination of Tp + NT. The minimum inhibitory combination of Tp + NT also reduced more than 20-fold the at least 1,000-fold resistance level of the R-plasmid mediated Tp resistance. This in vitro activity of NT and Tp could be of clinical relevance in the therapy of urinary tract infections due to multiple antibiotic-resistant strain

ISSN:0009-3157    

DOI:10.1159/000238324

出版商:S. Karger AG    

年代:1985

数据来源: Karger

摘要:

The in vitro activity of ceftriaxone, a cephalosporin derivative, recently introduced in Nigeria was compared with the activities of other related β-lactam antibiotics such as cefotaxime, cefuroxime, cephaloridine, cloxacillin/ampicillin and ampicillin against 530 local clinical isolates of gram-negative and gram-positive bacteria. The spectra of activity and potency of ceftriaxone and cefotaxime were generally similar against the Enterobacteriaceae, Pseudomonas aeruginosa, Serratia spp., Streptococcus spp. and Neisseria gonorrhoeae, but less active against Staphylococcus aureus and Staphylococcus epidermidis when compared to cefotaxime. All the other β-lactam antibiotics tested were less active than ceftriaxone. The action of ceftriaxone was bactericidal and the minimum inhibitory concentration values observed with R-plasmid β-lactamase mediated resistant Escherichia coli, Klebsiella spp., Proteus spp. and N. gonorrhoeae strains did not exceed the maximum value obtained with the β-lactamase-negative stra

ISSN:0009-3157    

DOI:10.1159/000238325

出版商:S. Karger AG    

年代:1985

数据来源: Karger

摘要:

The adherence of Escherichia coli of certain adhesin types can be influenced by subinhibitory concentrations of β-lactam antibiotics. Subinhibitory concentrations (¼MIC) of those penicillin and cephalosporin compounds which lead to filament formation increase mannose-sensitive adhesion (MS+). Antibiotics with ovoid cell formation did not change or only slightly reduced MS+ adherence. Strains with mannose-re-sistant (MR+) adhesins were not affected by these antibiotics. Only azthreonam increased the adherence of both MS+ and MR+ strains. Vancomycin and fosfomycin reduced the adherence of all strains tested. The degree of change was strain and antibiotic specific. No relation could be detected between the changes of adherence and the changes of hydrophobicity under the influence of antibiotics. Electron microscopic investigation has not yet yielded an explanation of the observed phenomeno

ISSN:0009-3157    

DOI:10.1159/000238326

出版商:S. Karger AG    

年代:1985

数据来源: Karger

摘要:

A semi-automated microdilution test was adapted for the in vitro testing of potential antitrichomonal agents. Washed cell suspensions of the pathogenic protozoan Trichomonas vaginalis were incubated in microtitration plates for 4 h at 37 °C in the presence of radiolabeled adenine and serial dilutions of the test compounds. After automatic harvesting of the cells onto filter paper discs, the extent of adenine uptake was estimated by scintillation counting. From the dose-response data it was possible to quantify accurately and rapidly the antitrichomonal activity of a range of compounds based on the inhibition of adenine uptake

ISSN:0009-3157    

DOI:10.1159/000238327

出版商:S. Karger AG    

年代:1985

数据来源: Karger

摘要:

Several uracil and cytosine nucleoside analogues with 2-hydroxyethoxy-methyl, 2-aminoethoxymethyl or 1,3-dihydroxypropoxymethyl side chains were synthesized and evaluated for cytostatic (L5178y mouse lymphoma cells) and antiviral (herpes simplex virus type 1 infected KB cells) activity. Two compounds exhibited anti-herpesvirus activity. These were 1-(2’-hydroxyethoxymethyl)-5-aza-cytosine and 1-(1’,3’-dihydroxypropoxymethyl)-5-iodouracil. The MIC values were 25.8 and 325.7 μg/ml, respec

ISSN:0009-3157    

DOI:10.1159/000238328

出版商:S. Karger AG    

年代:1985

数据来源: Karger