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Biomedical subjects

G Nicoletti

Publications and source records attributed to G Nicoletti.

At least 199 records · Page 11Linked to original sources
PubMed1988

In vitro interaction between cefotetan and aminoglycosides on Staphylococcus aureus and coagulase negative staphylococci, both methicillin-susceptible and -resistant.

The authors have evaluated the behavior of the interaction between cefotetan, a new cephalosporin with long acting resistance to the action of beta-lactamases, and gentamicin, amikacin and netilmicin against methicillin-susceptible and -resistant staphylococci. In 65.8% of the cases, drug combinations showed synergic effects. Results were subdivided for susceptibility or resistance to the drugs used in combination. In general, when both drugs were tested against methicillin-susceptible strains the results showed synergism.

Amikacin↗
PubMed1988

Treatment of bacterial peritonitis.

Cefotetan is a semi-synthetic cephamycin antibiotic. It has combined activity against aerobes and anaerobes which makes it of particular use in the treatment and prevention of intra-abdominal infections in the surgical patient. In the course of 3 years we have evaluated the therapeutic use of cefotetan in 107 patients. Early in the evaluation of this antibiotic we used cefotetan in combination with aminoglycosides in 35 severely ill patients with intra-abdominal infections. These patients were generally in poor condition. Good results were obtained in this high risk group. A further 72 patients received cefotetan monotherapy, usually at a dose of 2 g twice daily. The majority of these patients presented with intra-abdominal infections. Overall a successful clinical response of 94% was obtained with antibiotic therapy. In conclusion the results obtained support the therapeutic use of cefotetan in the treatment of moderate to severe intra-abdominal infection.

Adult↗
PubMed1987

Enterococci and aminoglycosides: evaluation of susceptibility and synergism of their combination with piperacillin.

Some clinical isolates of enterococci were tested for susceptibility to gentamicin, tobramycin, amikacin and netilmicin. Five percent of Streptococcus faecalis tested demonstrated high level resistance (minimum inhibitory concentration (MIC) greater than 2024 micrograms/ml) to gentamicin, tobramycin and netilmicin, while amikacin had MICs greater than 128 micrograms/ml for all strains tested. Since a combination of a beta-lactam and streptomycin does not produce synergism against all strains of enterococci for an increase in the number of highly resistant strains, the effect of piperacillin plus gentamicin, tobramycin, and netilmicin was examined. The combination piperacillin + netilmicin seemed to be very effective against all enterococci tested.

Aminoglycosides↗
PubMed1987

Further characterization of the in vitro and in vivo activity of ciprofloxacin against mycoplasmas.

The aim of this study was the evaluation of some parameters which might better characterize ciprofloxacin: the influence of inoculum, serum and medium. Resistance development, hamster protection and mycoplasmacidal concentrations were also investigated. Ciprofloxacin showed moderate antimycoplasmal activity, both in vitro and in vivo. The minimum inhibitory concentrations (MICs) for Ureaplasma urealyticum, if compared to those shown by erythromycin, are lower, but higher than those obtained with tetracyclines. Unlike the macrolides, ciprofloxacin suffers from change of inoculum size, but no single step resistance induction was reported both in ureaplasmas and mycoplasmas. If Mycoplasma pneumoniae pneumonia or genital infections due to U. urealyticum carry out gram-negative rod isolation, ciprofloxacin can be considered a valid therapeutic agent for these mixed infections.

Animals↗
PubMed1987

Growth and metastasis in allogeneic hosts. Lack of H-2-negative or somatic hybrid variant selection.

In vitro cultured B16 melanoma cells, which were previously found to have an impaired expression of H-2Kb and Db (as evaluated by antisera absorption assay), were used to study growth and metastasis in allogeneic mice in relation to H-2 expression. The possible emergence of somatic hybrids with host cells was also examined. B16-A cells grown subcutaneously in allogeneic BALB/c mice (H-2d) did not show a lack of H-2b expression, nor the acquirement of H-2d antigens was found. Spontaneous lung metastases were found in about 30% of BALB/c mice with progressing B16 tumor. Single lung metastases showed higher H-2b levels than cells from the respective tumors, and did not express host H-2 antigens. Tumor take was concomitant to the rise of an anti-H-2b humoral response: disease outcome was independent from the serum titer. B16-A cells injected intravenously in BALB/c mice gave rise to lung colonies; different colonies showed a wide range of H-2b antigens levels and no H-2d expression. Lung colonization capacity in normal allogeneic BALB/c mice was significantly higher than in syngeneic C57BL/6 mice. Both syngeneic and allogeneic mice, when pretreated with cyclophosphamide (CY) to reduce natural killer cell activity, showed a significant increase in lung colonization by B16-A cells. CY-treated C57BL/6 mice showed significantly higher numbers of lung colonies than CY-treated BALB/c mice. In conclusion, B16 growth and metastasis in the allogeneic environment do not seem to be determined by a selection of H-2-negative variants or by the emergence of somatic hybrids with host cells.

Animals↗
PubMed1987

Action of clindamycin-phosphate in foreign body infections due to Staphylococcus epidermidis in mice.

The virulence of Staphylococcus epidermidis strain slime producer was examined in an experimental model of foreign body infection in mice. In the course of this experimental infection the mice were injected with two antibiotics (clindamycin and cefazolin) active in vitro toward the Staphylococcus strain used. The results obtained after a week of antibiotic therapy show that clindamycin alone has a therapeutic action against the infection caused by S. epidermidis. Cefazolin showed a very poor therapeutic effect. The results are discussed on the basis of inflammatory reaction elicited from the foreign body and the characteristics of clindamycin in connection with the host's defense mechanisms.

Animals↗
PubMed1987

First microbiological approach to dactimicin, a novel aminoglycoside antibiotic.

Dactimicin (ST 900) is the first aminoglycoside antibiotic of Dactylosporangium origin. This drug shows resistance to many enzymes that destroy aminoglycosides. In this first approach, the authors have pointed out the activity of dactimicin against Gram-negative rods, particularly Klebsiella, Enterobacter, Serratia and Gram-positive bacteria, especially methicillin susceptible and resistant staphylococci. Dactimicin showed remarkable antibacterial activity against all strains tested; however this activity was strongly influenced by the inoculum size. The bactericidal activity of dactimicin towards some Gram-positive and Gram-negative bacteria was also evaluated.

Aminoglycosides↗
PubMed1987

The sensitivity of gram-negative and gram-positive bacteria to ofloxacin.

The in vitro antimicrobial activity of ofloxacin, a new fluorinated quinolone, was evaluated against 165 gram-negative rods, both fermentative and non-fermentative and against 57 gram-positive strains (coagulase-positive and -negative, staphylococci both methicillin-resistant and susceptible and Streptococcus faecalis). Minimal inhibitory concentrations were determined by using the macrodilution test and activity was compared with nalidixic acid, norfloxacin, ampicillin, piperacillin, ceftazidime and gentamicin for gram-negative rods, norfloxacin and gentamicin for Staphylococcus strains, and norfloxacin, ampicillin, piperacillin and gentamicin for enterococci. Ofloxacin inhibited all fermentative gram-negative bacteria tested, in a range of 0.05-3.12 micrograms/ml. It also had good antimicrobial activity against non-fermentative gram-negative strains: in fact it inhibited 90% of Acinetobacter and 80% of Pseudomonas aeruginosa tested at 3.12 micrograms/ml. Ofloxacin had good antimicrobial activity against Staphylococcus and Enterococcus tested.

Ampicillin↗
PubMed1987

In vitro activity of pefloxacin against gram-negative and gram-positive bacteria in comparison with other antibiotics.

The in vitro antibacterial activity of pefloxacin was evaluated against 310 gram-negative and 315 gram-positive aerobes, freshly isolated from clinical material. Reference antibiotics were: ofloxacin, ciprofloxacin, teicoplanin, vancomycin, rifampin, and methicillin for gram-positive cocci, and norfloxacin, nalidixic acid, ceftazidime, cefotaxime, piperacillin, netilmicin, gentamicin, amikacin, and aztreonam, for gram-negative bacilli. Gram-positive cocci were inhibited by 0.5 mg/l of teicoplanin, 1 mg/l of ciprofloxacin, 4 mg/l of both pefloxacin and ofloxacin, and 8 mg/l of vancomycin or rifampicin. Against gram-negative bacteria pefloxacin showed excellent activity, inhibiting 90% of all enterobacterial strains and 70% of other gram-negative aerobes at concentrations ranging between 0.03 and 4 mg/l. The same percentage of bacteria were inhibited by the other drugs at concentrations which resulted from two to fourfold higher than those of pefloxacin. MBCs and timed-kill tests indicated that this new agent is rapidly bactericidal against these isolates, and there were no significant differences in the rate of killing of both gram-positive and gram-negative bacteria. Inoculum size and pH did not change significantly the MIC values of pefloxacin.

Anti-Bacterial Agents↗