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PubMedDate not supplied

Anti-pseudomonal activity of HR 810.

The anti-pseudomonal activity of HR 810, a new 2-aminothiazolyl cephalosporin, was compared to that of carbenicillin, azlocillin and cefsulodin against 187 non-fermenters. HR 810 was the best agent against Pseudomonas aeruginosa, Pseudomonas putida, Pseudomonas fluorescens and Acinetobacter calcoaceticus with an MIC50 less than or equal to 4 mg/l and an MIC90 less than or equal to 16 mg/l. It was as effective as azlocillin against Pseudomonas stutzeri and Pseudomonas mendocina, with an MIC50 less than or equal to 0.25 mg/l and an MIC90 less than or equal to 1 mg/l. It was not active against other species of Pseudomonas or other non-fermenters such as Flavobacterium sp.

Acinetobacter↗
PubMed1989

Once-daily versus thrice-daily administration of netilmicin in combination therapy of Pseudomonas aeruginosa infection in a man-adapted neutropenic animal model.

A granulocytopenic mouse model was used to elucidate the impact of dose spacing on the activity of netilmicin against Pseudomonas aeruginosa. A thigh infection was produced and then treated with netilmicin combined with azlocillin. Netilmicin was injected subcutaneously at decreasing doses every 20 min to result in plasma-concentration-time curves similar to those observed in patients on intravenous netilmicin treatment. A once-daily regimen was simulated and compared to a simulated conventional schedule of every 8 h. Identical total amounts of drug were used in both groups of comparatively treated mice. Therapeutic efficacy was quantitated by repeated determinations of surviving organisms in thigh homogenates. Combination therapy was significantly more effective than azlocillin treatment alone. In combination regimens the simulated once-daily netilmicin schedule killed the target organisms faster than the simulated thrice-daily regimen and was significantly more efficacious by 24 and 32 h in two out of three strains of Pseudomonas aeruginosa tested. It is concluded that the results of combination therapy of severe Pseudomonas aeruginosa infections in the immunocompromised host might be improved by choosing an aminoglycoside dosage interval of 24 h instead of the conventional 8 h.

Animals↗
PubMed1987

Resistant strains of Pseudomonas aeruginosa isolated after exposure to several beta-lactam antibiotics.

Successive transfer of three clinical isolates of Pseudomonas aeruginosa in liquid medium containing serial dilutions of several beta-lactam antibiotics was used to isolate resistant variants. The alpha-carboxy-penicillins (carbenicillin and ticarcillin), the acylureidopenicillins (piperacillin and azlocillin) and cephalosporins (moxalactam, cefoperazone, cefsulodin and ceftazidime) were used as the selective antibiotics. Resistant variants were isolated from two of the three strains (strains 27 and 45), using an inoculum size of 10(4)-10(5) CFU/ml, which showed a mean 5 to 8-fold increase in MIC for most of the selected antibiotics. The 27-carbenicillin and 27-cefsulodin resistant variants showed beta-lactamase production similar to that of the parent. However, alterations were found in outer-membrane proteins and lipopolysaccharides. With azlocillin, moxalactam and ceftazidime as the selective antibiotics, resistant variants were isolated from strains 27 and 45 which showed a stable increased constitutive beta-lactamase production. From the third strain, 9150, the only variants isolated showed a two dilution-step increase in MIC to the antibiotics tested. The beta-lactamase production, outer-membrane proteins and lipopolysaccharides of these variants were similar to those of the parent.

Anti-Bacterial Agents↗
PubMed1990

Gram-positive bacteraemia in granulocytopenic cancer patients.

In the four EORTC International Antimicrobial Therapy Cooperative Group trials, the frequency of gram-positive isolates has increased significantly from 29% of single-organism bacteraemias in trial I (1973-1976) to 41% in trial IV (1983-1985). In trial IV febrile and neutropenic (less than 1000 polymorphonuclear lymphocytes per microliter) cancer patients were randomized prospectively to receive either azlocillin plus a long course (at least 9 days) of amikacin, or ceftazidime plus a short course (3 days) of amikacin, or ceftazidime plus a long course of amikacin. Without modification of the allocated antibiotics, the overall response rates for gram-positive bacteraemias were similar for all three regimens (19/37 [51%], 8/23 [35%] and 14/30 [47%]), respectively. However, in patients with prolonged and severe neutropenia, treatment with azlocillin plus amikacin was significantly more effective than with ceftazidime plus 3 days' amikacin (7/10 vs. 0/7). The overall response rate for these infections was significantly lower than that observed in trial I (46% vs. 74%), but this was not associated with increased mortality. The response to treatment was significantly influenced by the susceptibility of the infecting strain to the beta-lactam. Multivariate analysis revealed that increasing age, presence of a central venous catheter and resistance to beta-lactam adversely affected outcome. Future studies should be designed to improve the outcome of gram-positive bacteraemia in neutropenic patients with cancer.

Agranulocytosis↗
PubMed1987

Determination of synergy by two methods with eight antimicrobial combinations against tobramycin-susceptible and tobramycin-resistant strains of Pseudomonas.

Eleven strains of tobramycin-susceptible Pseudomonas aeruginosa, 12 strains of tobramycin-resistant P. aeruginosa, and 11 strains of P. maltophilia were tested against tobramycin in combination with azlocillin, piperacillin, ceftazidime, and imipenem and against colistin in combination with azlocillin, piperacillin, ceftazidime, and imipenem by microdilution checkerboard and time-kill curve techniques. Synergistic or additive effects were demonstrated in the tobramycin-ceftazidime combination against tobramycin-resistant strains of P. aeruginosa and P. maltophilia, and with all tobramycin combinations against tobramycin-susceptible strains of P. aeruginosa using the checkerboard technique. Synergistic and additive effects were seen with the time-kill curve technique with colistin-ceftazidime, colistin-imipenem, and tobramycin-piperacillin combinations against tobramycin-susceptible P. aeruginosa and in the colistin-ceftazidime combination against tobramycin-resistant P. aeruginosa. Fractional inhibitory concentrations (FIC) and fractional bactericidal concentrations (FBC) from checkerboard studies were compared to the time-kill curve results and vice versa. The overall agreement with FIC was 39.4% and 40.9% and agreement with FBC was 40.9% and 43.9%. This limited study illustrates the lack of agreement between these techniques in demonstrating antimicrobial synergy against pseudomonads.

Azlocillin↗
PubMed1994

Ciprofloxacin resistant Serratia marcescens endocarditis as a complication of non-Hodgkin's lymphoma.

We report a case of endocarditis caused by a ciprofloxacin-resistant strain of Serratia marcescens in a 50-year-old female neutropenic patient with non-Hodgkin's lymphoma which occurred while receiving ciprofloxacin prophylaxis. She made poor progress on first line therapy with azlocillin and gentamicin by bolus injection t.d.s. The infection was finally eliminated by a regimen of continuous infusion of azlocillin and once daily gentamicin.

Azlocillin↗
PubMed1987

Ceftazidime combined with a short or long course of amikacin for empirical therapy of gram-negative bacteremia in cancer patients with granulocytopenia.

To determine whether combination antibiotic therapy including a short course of an aminoglycoside was as effective and less toxic than a conventional long course of the combination for the empirical therapy of gram-negative bacteremia in patients with cancer and granulocytopenia, we conducted a randomized multicenter trial comparing ceftazidime plus a short course (three days) of amikacin, ceftazidime plus a long course (nine days) of amikacin, and azlocillin plus a long course (nine days) of amikacin. Single-organism gram-negative bacteremia occurred in 129 of 872 evaluable patients. Without a change in antibiotics, the response rates were 81 percent with ceftazidime and long-course amikacin, 48 percent with ceftazidime and short-course amikacin (P = 0.002), and 40 percent with azlocillin and long-course amikacin (P less than 0.001). Among patients with fewer than 100 granulocytes per cubic millimeter throughout therapy, the response rates were 6 percent with ceftazidime and short-course amikacin and 50 percent with ceftazidime and long-course amikacin (P = 0.03). Linear logistic-regression analysis showed that therapy with ceftazidime and long-course amikacin was the most favorable prognostic factor of the response to infection, whereas the presence of leukemia or shock was the least favorable. We conclude that ceftazidime should be given in combination with a conventional full course of an aminoglycoside (amikacin) when used for the empirical treatment of gram-negative bacteremia in cancer patients with granulocytopenia.

Adolescent↗
PubMed1987

Beta-lactamase lability and inducer power of newer beta-lactam antibiotics in relation to their activity against beta-lactamase-inducibility mutants of Pseudomonas aeruginosa.

The interactions of imipenem, carbenicillin, cefotaxime, ceftriaxone, and azlocillin with the chromosomal beta-lactamase of Pseudomonas aeruginosa were compared. Imipenem was hydrolyzed very slowly (kcat, 1/min) and induced beta-lactamase synthesis strongly. Its minimal inhibitory concentrations (MICs) reflected this behavior, being equal (1-2 micrograms/ml) for enzyme-inducible strains and their stably derepressed mutants. Mutants that had basal (i.e., minimal and uninducible) enzyme production were eight- to 16-fold more susceptible to imipenem than were inducible or stably derepressed strains. Carbenicillin was stable to hydrolysis (kcat, less than 0.1/min) and induced weakly at low concentrations. Consequently its MICs were equal for beta-lactamase-inducible strains and for their basal mutants. Stable beta-lactamase derepression generally did not increase resistance to carbenicillin significantly. Azlocillin, cefotaxime, and ceftriaxone were labile to hydrolysis (kcat, 12-297/min) but induced poorly. Consequently their MICs for enzyme-inducible strains equaled those for basal mutants but were elevated for derepressed mutants.

Anti-Bacterial Agents↗
PubMed1983

Alternative antibiotics for the treatment of Pseudomonas infections in cystic fibrosis.

We have investigated the effectiveness of seven new beta-lactam antibiotics, azlocillin, piperacillin, ceftazidime, cefsulodin, cefoperazone, latamoxef (moxalactam), and cefotaxime, against acute pulmonary exacerbations caused by Pseudomonas aeruginosa in cystic fibrosis. Three hundred and fifty-five strains of Ps aeruginosa isolated from 310 sputum cultures (190 cystic fibrosis patients) were tested for susceptibility to the drugs by determination of minimal inhibitory concentrations (MIC). The highest activity was shown by ceftazidime (6% resistant strains) followed by cefsulodin and piperacillin (15 and 16% resistant strains); very low activity was found for cefotaxime and latamoxef (moxalactam). Ceftazidime was the most active drug against 32 pseudomonas isolates that were resistant to both carbenicillin and aminoglycosides (78% susceptible). A randomized, double-blind trial of azlocillin, piperacillin, ceftazidime, cefsulodin or cefoperazone was performed in 111 cystic fibrosis patients with predominant and susceptible pseudomonas in their sputum. Results were evaluated by a clinical, radiological and bacteriological scoring system: the best results were obtained with ceftazidime, followed by cefsulodin and piperacillin. However, pseudomonas was eradicated in only 22 (23%) of the cases with the most active drugs and persisted or reappeared in all the cases 1 to 3 months later. Ceftazidime always eradicated Staph. aureus and Haemophilus influenzae associated with pseudomonas. Similar eradication occurred nearly always with cefsulodin but rarely with the other drugs. No serious drug reaction occurred but a later fever and rash with piperacillin, transient diarrhoea with cefoperazone, vomiting with cefsulodin, and very frequent eosinophilia with ceftazidime should be mentioned. These five drugs offer, in varying degree, alternatives to traditional anti pseudomonas antibiotics in cystic fibrosis pulmonary infections, but they should be used only against well-proven resistant strains. Ceftazidime is best and cefotaxime and latamoxef (moxalactam) least useful.

Adolescent↗
PubMed1984

The effect of clavulanic acid on the susceptibility of Bacteroides fragilis to three acyl-ureidopenicillins, ampicillin and carbenicillin.

The susceptibilities of 50 clinical isolates of the Bacteroides fragilis group to ampicillin, carbenicillin, mezlocillin, azlocillin and piperacillin were similar, modal MICs being 8-32 mg/l. However, in the presence of clavulanic acid, 45 and 43 strains became susceptible (MIC less than or equal to 4 mg/l) to ampicillin and carbenicillin respectively whilst 27, 37 and 35 strains became susceptible (MIC less than or equal to 4 mg/l) to mezlocillin, azlocillin and piperacillin. Clavulanic acid did not influence the susceptibility of six (12%) strains. The isoelectric points of the beta-lactamases from Bact. fragilis and Bact. thetaiotaomicron were similar to those found by others.

Ampicillin↗
PubMed1986

Effects of inoculum size on the activity of carboxy- and ureido-penicillins and effects of combinations of ureido-penicillins with aminoglycosides against resistant Pseudomonas aeruginosa.

Effects of inoculum size on the comparative activity of carbenicillin, ticarcillin, mezlocillin, piperacillin and azlocillin against 20 strains of Pseudomonas aeruginosa known to be relatively resistant to carbenicillin were studied by using 10(4), 10(5) and 10(6) cfu/ml. Inoculum size markedly affected the susceptibility of Ps. aeruginosa to these antibiotics. An increase in the inoculum size from 10(4) to 10(5) cfu/ml had more effects on the MIC of the ureido-penicillins than the carboxy-penicillins. Mezlocillin, piperacillin and azlocillin with gentamicin or tobramycin showed mainly indifference. Synergism or antagonism were demonstrated against a few strains.

Azlocillin↗
PubMed1985

Antimicrobial activity of ciprofloxacin against Pseudomonas aeruginosa, Escherichia coli, and Staphylococcus aureus determined by the killing curve method: antibiotic comparisons and synergistic interactions.

A derivative of quinolinecarboxylic acid, ciprofloxacin (BAY o 9867) was found to be an effective bactericidal agent against Pseudomonas aeruginosa and Escherichia coli. A bactericidal effect was achieved immediately after the addition of ciprofloxacin. At a concentration of 0.5 micrograms/ml, culture viability was reduced from 5 X 10(5) to about 5 X 10(3) CFU/ml within 15 min, and at 0.1 micrograms/ml, a greater than 10-fold reduction in viability resulted during the first hour after exposure. This bactericidal activity observed during the lag phase in Mueller-Hinton broth was also demonstrated in a nongrowing system. The antibiotics used in comparative studies, i.e., tobramycin, aztreonam, cefotaxime, and azlocillin, did not show this initial bactericidal activity, and ciprofloxacin prevented culture regrowth at lower concentrations. Staphylococcus aureus was not as susceptible to ciprofloxacin; killing occurred at a concentration of 0.5 micrograms/ml only after the onset of exponential growth in the control culture. Synergistic interactions were observed with ciprofloxacin in combination with tobramycin and azlocillin against P. aeruginosa and with cefotaxime and tobramycin against E. coli.

Azlocillin↗
PubMed2005

Structure-activity relationships of different beta-lactam antibiotics against a soluble form of Enterococcus faecium PBP5, a type II bacterial transpeptidase.

Penicillin-binding proteins (PBPs) catalyze the essential reactions in the biosynthesis of cell wall peptidoglycan from glycopeptide precursors. beta-Lactam antibiotics normally interfere with this process by reacting covalently with the active site serine to form a stable acyl-enzyme. The design of novel beta-lactams active against penicillin-susceptible and penicillin-resistant organisms will require a better understanding of the molecular details of this reaction. To that end, we compared the affinities of different beta-lactam antibiotics to a modified soluble form of a resistant Enterococcus faecium PBP5 (Delta1-36 rPBP5). The soluble protein, Delta1-36 rPBP5, was expressed in Escherichia coli and purified, and the NH(2)-terminal protein sequence was verified by amino acid sequencing. Using beta-lactams with different R1 side chains, we show that azlocillin has greater affinity for Delta1-36 rPBP5 than piperacillin and ampicillin (apparent K(i) = 7 +/- 0.3 microM, compared to 36 +/- 3 and 51 +/- 10 microM, respectively). Azlocillin also exhibits the most rapid acylation rate (apparent k(2) = 15 +/- 4 M(-1) s(-1)). Meropenem demonstrates an affinity for Delta1-36 rPBP5 comparable to that of ampicillin (apparent K(i) = 51 +/- 15 microM) but is slower at acylating (apparent k(2) = 0.14 +/- 0.02 M(-1) s(-1)). This characterization defines important structure-activity relationships for this clinically relevant type II transpeptidase, shows that the rate of formation of the acyl-enzyme is an essential factor determining the efficacy of a beta-lactam, and suggests that the specific side chain interactions of beta-lactams could be modified to improve inactivation of resistant PBPs.

Acylation↗
PubMed1990

[Cesarean section and postoperative infectious-inflammatory complications. II. A comparative evaluation of 2 methods for antibiotic prophylaxis in cesarean section].

The authors compare two methods for antibiotic prophylaxis of infectious-inflammatory complications in cesarean section: 1. Widely distributed mass prophylaxis with penicillin and gentamicin and 2. selective prophylaxis with Azlocillin, performed after determination, of the degree of the risk. 233 cesarean section were included in the study, 122 of which were treated by the first method. 59 out of 11 cesarean sections were evaluated as such with high risk and respectively treated with Azlocillin, but 52 of the women with low risk were not treated with antibiotic. The results show the advantages and economic benefits of the selective antibiotic prophylaxis in cesarean section.

Anti-Bacterial Agents↗
PubMed1989

Study of in vitro antibacterial activity of 19 antimicrobial agents against Pseudomonas aeruginosa.

The in vitro antibacterial activity of 19 antimicrobial agents against 40 strains of P aeruginosa was studied. The 19 antimicrobial agents included 7 semisynthetic penicillins, 6 third generation cephalosporins, 5 aminoglycosides and 1 quinolone agent. The minimal inhibition concentrations (MIGs) were measured by the serial dilution on solid agar. Ceftazidime was the most active in 19 antimicrobial agents again P aeruginosa (MIC50: 1 microgram/ml, MIC90: 2 micrograms/ml) Amikacin and ofloxaxin followed it in activity. Acylureido-penicillins, such as azlocillin, furbenicillin and piperacillin were highly active against P aeruginosa, which could inhibit, 92.5%, 90% and 85% of these strains at a concentration of 8 micrograms/ml. Cefsulodine and cefoperazone were also active against the same strains, inhibiting 92.5% and 99% of the strains at a concentration of 8 micrograms/ml. The potency of the agents mentioned above against P. aeruginosa was similar to that of aminoglycosides. The drug susceptibility of 10 strains isolated in our hospital was compared with that of 29 strains of other hospitals in Beijing. The MICS of 5 penicillins and 3 cephalosporins against the isolates of our hospital was higher than that of other hospitals, suggesting that the susceptibility of beta-lactam antibiotics against isolates of our hospital was lower. The effects of combined use of azlocillin with oxacillin and piperacillin with ofloxacin against 4 strains of carbenicillin-resistant P aeruginosa was studied using check-board testing. The synergy and partial synergy were observed in both combinations.

Azlocillin↗
PubMed1985

[Potentiation of the effect of non-depolarizing muscle relaxants by acylaminopenicillins. Studies on the example of vecuronium].

In a prospective controlled clinical study interactions between nondepolarizing muscle relaxants and acylaminopenicillins were investigated electromyographically. Six patients in each group received either apalcillin, azlocillin, mezlocillin or piperacillin during the operation. Muscle relaxation was maintained using the short acting nondepolarizing relaxant vecuronium, which shows no cumulative effect within clinical dosages. The intra-individual comparison with the control period (100%) showed a significant prolongation of the duration of action after a fixed dose of vecuronium. The mean increase was +26% following apalcillin, +46% after piperacillin, +38% following mezlocillin and +55% following azlocillin. The shortest time of the control periods was 8.6 min and the maximum time was 32.6 min. We also found a significant depression of the EMG-response. No significant differences could be detected between the four antibiotics. The method described here has proven to be sensitive enough to detect clinically relevant interactions with muscle relaxants. As a result of our study, caution seems to be necessary if acylaminopenicillins are administered in the early postoperative period.

Adult↗
PubMed1988

[Ciprofloxacin in combination with other antimicrobial substances].

The antibacterial activity of ciprofloxacin, either alone or in combination with azlocillin, imipenem, mezlocillin or tobramycin, was tested against enterococcus and pseudomonas species. No synergy or antagonism was found by means of the checkerboard titration method used. Subsequently, the bactericidal activity of ciprofloxacin (2 x minimal inhibitory concentration, MIC), azlocillin, imipenem, mezlocillin or tobramycin (2 x MIC) either alone or in combination (1 x MIC each of each substance) was tested against individual strains. No reduction of bactericidal activity in comparison with the effect of the single substances at higher concentration was found, even though the concentrations of each substance were halved. An antagonism is unlikely when ciprofloxacin is combined with one of the beta-lactams studied or with tobramycin. More likely is a slight synergistic effect.

Anti-Bacterial Agents↗
PubMed1988

High ambient pressure of 41 bar increases the cerebral toxicity of penicillins.

Sodium benzylpenicillin, cloxacillin, and azlocillin were infused intravenously in awake rats at 1 and 41 bar until they convulsed. The doses necessary to elicit convulsions were significantly lower at 41 than at 1 bar, i.e., with a 24% (P less than 0.0005) lower dose of benzylpenicillin and a 23% lower dose of azlocillin (P less than 0.005). The convulsion threshold of cloxacillin was also lower (13%), but not statistically significant. The results show that high pressure reduces the convulsion threshold for some penicillins. Hippocampal amino acid concentrations were also measured in animals exposed to 1 and 41 bar with and without benzylpenicillin treatment. Infusion of benzylpenicillin at 1 bar led to a decrease of 15% in the glutamate level (P less than 0.05), whereas at 41 bar it decreased the level of glutamate by 17% (P less than 0.05) as well as that of glutamine by 19% (P less than 0.05). The results suggest that treatment with penicillin at high ambient pressure may increase the turnover of transmitter glutamate in the rat hippocampus and thus increase the excitability. These effects should be considered when high doses of penicillins are administered to man at high ambient pressure.

Amino Acids↗