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Biomedical subjects

A M Cuffini

Publications and source records attributed to A M Cuffini.

At least 55 records · Page 3Linked to original sources
PubMed1989

Influence of cefotaxime on Staphylococcus aureus with respect to their interaction with macrophages.

Many antibiotics in addition to their direct effect on bacteria can modulate host defence in different ways. The influence of cefotaxime on the phagocytic and bactericidal activity of mouse peritoneal macrophages was investigated. At concentrations of half the MIC the antibiotic caused macrophages to kill intracellular Staphylococcus aureus at a higher level than did macrophages without drug. Bacteria pretreated with cefotaxime became more sensitive to macrophage phagocytic and bactericidal activity. Macrophages taken from mice receiving intravenous cefotaxime showed greater phagocytic capacity than those from control mice.

Animals↗
PubMed1987

Synergy of ceftazidime and human macrophages on phagocytosis and killing of Staphylococcus aureus and Pseudomonas aeruginosa.

The effect of ceftazidime on the phagocytic and bactericidal activity of human macrophages was investigated. At concentrations of half the MIC the antibiotic caused macrophages to ingest and kill Staphylococcus aureus and Pseudomonas aeruginosa at a higher level than did macrophages without drug. Bacteria pretreated with ceftazidime became more sensitive to the bactericidal activity of macrophage lysozyme. Macrophages taken from mice receiving intravenous ceftazidime showed greater phagocytic activity than those from control mice.

Ceftazidime↗
PubMed1987

Effect of fosfomycin trometamol on bacterial adhesion in comparison with other chemotherapeutic agents.

The effect of fosfomycin trometamol in comparison with that of norfloxacin and co-trimoxazole on the hemagglutination, yeast cell aggregation and adhesive properties of both gram-positive and gram-negative microorganisms was studied. The strains were isolated from the urine of patients with urinary tract infections, or from vaginal swabs. At sublethal concentrations (1/4 and 1/8 of the minimal inhibitory concentration), the ability of the bacteria to adhere to human uroepithelial cells was reduced by any of the 3 drugs assayed. The reduction corresponded to a decrease in the agglutinating activity of the gram-negative bacteria tested, such providing further evidence for the efficacy of the different chemoantibiotics. In particular, fosfomycin trometamol and norfloxacin proved to be more effective than co-trimoxazole in affecting the adhesive properties of all the strains employed.

Bacterial Adhesion↗
PubMed1987

Imipenem: morphological changes and lethal effects on Pseudomonas aeruginosa.

Imipenem, a new carbapenem antibiotic shows an extremely broad spectrum of antibacterial activity for almost all Gram-negative and Gram-positive aerobic and anaerobic bacteria. It is stable to beta-lactamases and shows a high affinity for PBP 2. The changes in morphology and ultrastructure caused by the antibiotic on Ps. aeruginosa confirm that imipenem acts by binding primarily to PBP 2, resulting in irregular and round shaped cells, and later during treatment to PBP 1 with cellular lysis. The involvement of PBP 1 is also demonstrated by the fast bactericidal kinetics on Ps. aeruginosa, E. coli and Staph. aureus.

Anti-Bacterial Agents↗
PubMed1987

Relationship between growth rate and phagocytosis susceptibility in Streptococcus mutans.

Streptococcus mutans strain GS-5 was grown in a variety of carbon sources in order to achieve different balanced growth rates, ranging from 61 to 383 minutes. The influence of the S. mutans growth rate on mouse phagocyte activity against these bacteria has been evaluated. The percentages of bacteria phagocytized and intracellularly killed by macrophages rose to 60-80% and 85-95% respectively when the doubling time was longer, showing that S. mutans is particularly sensitive to nonspecific immune defence mechanisms when cultured under conditions similar to those of its natural ecosystem.

Animals↗
PubMed1985

The penetration of rifampicin, pyrazinamide, and pyrazinoic acid into mouse macrophages.

The degree of penetration of rifampicin, pyrazinamide, and its metabolite pyrazinoic acid in mouse macrophages was evaluated over a period of 24 h. Cell cultures were exposed to 14C-labeled drugs at concentrations corresponding to peak, trough, and intermediate serum concentrations observed in humans after administration of therapeutic doses. The study was carried out with dead, resident, and stimulated peritoneal macrophages. The results indicated that the 3 compounds penetrate macrophages rapidly. At the lower concentrations, uptake of the 3 drugs is practically complete. With increasing concentrations, the absolute amount in the intracellular compartment increased. Comparison of the degree of penetration of the 3 drugs into dead, resident, and stimulated macrophages seems to suggest that the process of transfer through the macrophage wall is of a passive nature and not related to the metabolic state of the cells. Analysis of the binding of the 3 drugs to intracellular proteins indicated that more binding sites are probably available for rifampicin than for the other 2 drugs.

Animals↗
PubMed1985

Killing of macrophage-ingested mycobacteria by rifampicin, pyrazinamide, and pyrazinoic acid alone and in combination.

A study was undertaken with the aim of assessing the killing capacity of rifampicin, pyrazinamide, and pyrazinoic acid on macrophage-ingested, live Mycobacterium tuberculosis. The 3 drugs were used at concentrations corresponding to the average peak levels observed in humans after administration of therapeutic doses that had been found to penetrate into macrophages in a previous study. The degree of killing was studied after exposure of the cell cultures to the individual drugs and their combinations for 3, 18, 24, 48, and 72 h. Comparing the degree of killing in the control, drug-free cultures with that observed in the drug-containing systems, over a period of 3 to 24 h, indicated that in these a greater, more rapid, although not statistically significant, killing of intracellular mycobacteria took place. At 48 h the degree of killing was similar in the control and in the drug-containing cell cultures. Between 48 and 72 h, however, a marked growth of intracellular mycobacteria was observed in the control cultures. This phenomenon was much less evident in the drug-containing cultures. No major increase in the killing effect with respect to that observed with the individual drugs was found after exposure of the macrophages to all possible combinations of the 3 drugs.

Animals↗
PubMed1985

Susceptibility of clinical isolates of gram-positive and gram-negative organisms to cefatrizine.

The in vitro activity of cefatrizine was evaluated against 294 Gram-positive and 270 Gram-negative bacteria isolated from clinical specimens. Cefatrizine had excellent activity against Gram-positive cocci, inhibiting all except enterococci at minimal inhibitory concentrations below 1 mcg/ml. Moreover, cefatrizine was an effective antibacterial agent for most major Gram-negative species. Cefatrizine activity was tested against 34 strains of H. influenzae and 37 strains of K. pneumoniae and compared with that of other orally administered cephalosporins. Cefatrizine MIC50 values were much lower than those recorded for cephalexin and cefadroxil.

Cefatrizine↗
PubMed1982

Phagocytosis and killing of cefazolin-exposed Staphylococci and Bacilli by mouse peritoneal macrophages.

The phagocytic and microbicidal capacity of proteose peptone-induced macrophages from Balb/c mice was assessed in vitro against Staphylococcus aureus and Bacillus subtilis in the presence of a subinhibitory concentration of cefazolin. Enhanced phagocytosis (50-60%) and a similar killing effect (99%) after two hours, incubation was noted towards both test organisms. Electron microscopy showed phagocytic activity on both control and antibiotic-treated strains. Since cefazolin does not penetrate macrophages, the peritoneal cell morphology and ultrastructure were unaffected by the drug.

Animals↗
PubMed1982

Structural changes induced by subinhibitory concentrations of fosfomycin on Staphylococcus aureus and Bacillus cereus.

Exposure of Staphylococcus aureus ATCC 6538 and Bacillus cereus ATCC 11778 to 1/2 MIC fosfomycin for 3 and 6 h was studied by transmission and scanning electron microscopy. After 3 h, a loss of density and irregularity of shape in the septum was noted, while after 6 h a delayed separation of newly formed cells was observed in both species. In Staphylococcus aureus this resulted in the formation of chains of intact cells and cells in lysis. In Bacillus cereus, it produced filamentous forms with multiple septa. the differences between the effects observed at 3 h and 6 h may be due to time-related variations in cell permeability to fosfomycin, or to the existence of indirect mechanisms enabling fosfomycin to interfere with the enzymatic activity regulating the normal separation of cells, or to a combination of these factors.

Anti-Bacterial Agents↗
PubMedDate not supplied

[Determination of the bactericidal potency of cefatrizine and other oral antibiotics against Haemophilus influenzae, Klebsiella pneumoniae and Streptococcus pyogenes].

The in vitro determination of the T log and the minimal bactericidal time of cefatrizine was evaluated against H. influenzae, Str. pyogenes A isolated from clinical specimens. and K. pneumonia ATCC 10031 and compared with that of amoxycillin, cefaclor, cefroxadine and miocamycin against the same bacterial strains. Cefatrizine demonstrate the shorter TMB against all bacterial strains and antibiotic tested with MBCs.

Administration, Oral↗
PubMedDate not supplied

[Use of ofloxacin in otorhinolaryngologic infections].

Ofloxacin, a new fluoroquinolonic synthetic compound with broad antibacterial spectrum, was used in per os therapy of 15 ear, nose and throat infected patients. The antibiotic was then compared with other eight antimicrobial agents against the Gram-positive and Gram-negative isolates. Either in vitro than in vivo the god antibacterial activity and tolerance of ofloxacin, particularly against Gram-positive infections, was demonstrated. Results point out the possibility of utilization of ofloxacin per os against ear, nose and throat infections.

Administration, Oral↗
PubMedDate not supplied

[In vitro comparative activity of norfloxacin in the comparison of pathogenic bacteria of the urinary tract].

In this study 411 bacterial isolates from clinical urinary tract infections against some quinolones, azthreonam and trimethoprim + sulfamethoxazole combination were tested. Bactericidal kinetics of norfloxacin , cinoxacin and azthreonam against E. coli ATCC 25922 was determined. Both MICs values and bactericidal activities have shown that fluoroquinolones are more active against all Gram-positive and Gram-negative bacteria tested than the other drugs.

4-Quinolones↗
PubMedDate not supplied

[Comparative activity of norfloxacin and other chemotherapeutic agents on the adhesion of bacteria of the uro-vaginal tract to uroepithelial cells].

A number of bacterial strains (Escherichia coli, Proteus mirabilis and streptococci), obtained from patients with urinary infections, or from vaginal tampons, were assayed in order to evaluate their ability to adhere to uroepithelial cells. We employed, at a comparative purpose, two different methods to eliminate unattached bacteria: the centrifugation technique and the filtration technique. The effect of the pretreatment with subinhibitory concentrations of three chemotherapeutics widely employed in the urological practice (norfloxacin, pipemidic acid and co-trimoxazole) was determined on the strains which demonstrated a good rate of attachment. Growth in the presence of any of the three drugs decreased the adhesive properties of the microorganisms, reducing both the haemagglutination and the yeast aggregation titers of Gram-negative bacteria as well as their adhesiveness. Norfloxacin proved to be the most effective drug in affecting the pathogenicity characteristics of the assayed strains in comparison with the other two chemotherapeutics tested, even if they were also moderately able to inhibit the adhesiveness of the same strains.

Anti-Bacterial Agents↗
PubMedDate not supplied

[Comparative study of the in vitro activity of dibekacin, piperacillin, cefotaxime and cefuroxime on gram-negative bacteria].

The activity in vitro of the dibekacin was compared with that of piperacillin, cefotaxime and cefuroxime against 266 recently isolated gramnegative pathogens. Dibekacin was consistently more potent than cefotaxime, cefuroxime and piperacillin, with MIC50 and MIC90 values lower than the others. Dibekacin and cefotaxime were essentially similar in activity against all the bacteria, with the singular exception of Pseudomonas aeruginosa, which was markedly more susceptible to the former drug.

Anti-Bacterial Agents↗