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G Ravizzola

Publications and source records attributed to G Ravizzola.

At least 37 records · Page 2Linked to original sources
PubMed1989

Rufloxacin (MF-934): in vitro and in vivo antibacterial activity.

Rufloxacin (MF-934) is a new quinolone which shows in vitro antibacterial activity against E. coli, Salmonella, Klebsiella, Proteus and Staphylococcus spp. Lower in vitro activity was observed with Pseudomonas, Serratia, Enterobacter and the streptococci group D. The antimicrobial activity of MF-934 in vitro is higher than that of nalidixic acid but lower than that of ciprofloxacin, ofloxacin, pefloxacin or norfloxacin. The protective effects of MF-934 in systemic infections in mice are lower than those of ciprofloxacin and ofloxacin. In respiratory infections in rats and in subcutaneous infections in guinea-pigs, the protective effects of MF-934 are of the same order as ciprofloxacin and ofloxacin. This is probably due to the pharmacokinetic properties of MF-934, i.e. the long half-life and tissue concentrations higher than plasma levels.

4-Quinolones↗
PubMed1988

Evaluation of the expression of IFN-gamma in lymphocytes using a monoclonal antibody and flow cytometry.

A stable hybridoma cell line secreting specific antibodies against human interferon-gamma (IFN-gamma) and designated IGMB-14 has been established. It belongs to the IgG1, kappa subclass and it reacts in Western blot with the 28 kDa and 56 kDa polypeptides present in two different affinity purified IFN-gamma preparations. Peripheral blood mononuclear cells (PBMC) from a healthy individual, stimulated in vitro by PHA, were analysed for IFN-gamma production both when viable and following fixation. The presence of cytoplasmic or surface IFN-gamma was visualized by an indirect immunofluorescence assay using monoclonal antibody (MAb) IGMB-14 and a single laser FACS-III fluorescence-activated cell sorter. The staining permitted the detection of newly synthesized cytoplasmic IFN-gamma molecules in lymphocytes at day 1 after PHA stimulation and surface IFN-gamma at day 2. IFN-gamma was expressed on almost all the CD4+ lymphocytes as shown by a double staining technique. The specificity of the reaction was confirmed by Western blots and abolishing IFN-gamma staining by pretreatment of MAb IGMB-14 with IFN-gamma. The presence of surface IFN-gamma was also visualized on freshly isolated PBMC from two patients suffering from measles and AIDS but not on PBMC from a healthy individual. The experiments showed that this immunofluorescent method is useful for the detection, enumeration, and phenotypic characterization of IFN-gamma-producing cells in vitro and, in addition, for evaluating the presence of PBMC expressing IFN-gamma on their surface during a viral disease.

Animals↗
PubMed1987

Antibiotic resistances and plasmids in Staphylococcus aureus from Italian hospitals.

A total of 473 Staphylococcus aureus isolates from six Italian hospitals was examined for susceptibility to several antimicrobial agents and for plasmid content. Methicillin-resistant S. aureus (MRSA) were characterised by a plasmid of mol. wt (10(6)) 18-22 or 25 that carried the determinants for penicillinase production, resistance to cadmium ions and resistance to tetracycline. MRSA isolates usually harboured other smaller plasmids of mol. wt (10(6)) 2.8, 2.6 and 1.65 that encoded resistance to tetracycline, chloramphenicol and erythromycin, respectively, and cryptic plasmids of mol. wt (10(6)) c. 2 and 1 were found frequently. Methicillin-sensitive S. aureus (MSSA) that produced penicillinase often carried plasmids of mol. wt (10(6)) 11 or 13. No particular difference was found in plasmid patterns of strains from the various sources. Analysis of plasmids by EcoRI digestion showed that plasmids of similar mol. wt and phenotypic characteristics may have different restriction patterns, but often share one or more fragments in common.

Cross Infection↗
PubMed1987

Comparison of the in vitro antibacterial activity of teicoplanin and vancomycin against gram-positive cocci.

The antibacterial activity of teicoplanin and vancomycin against 231 clinical isolates of staphylococci and enterococci was evaluated by standardized agar dilution testing. The two antibiotics showed similar activity against staphylococci. However teicoplanin was significantly more active against enterococci. Killing curves indicated that the bactericidal activity of teicoplanin at the concentration of 2 X MIC was equal to its activity at 8 X MIC.

Anti-Bacterial Agents↗
PubMed1986

Radiometric method for the rapid detection of Leptospira organisms.

A rapid and sensitive radiometric method for detection of Leptospira interrogans serovar pomona and Leptospira interrogans serovar copenhageni is described. Stuart's medium and Middlebrook TB (12A) medium supplemented with bovine serum albumin, catalase, and casein hydrolysate and labeled with 14C-fatty acids were used. The radioactivity was measured in a BACTEC 460 (Johnston Laboratories). With this system, Leptospira organisms were detected in human blood in 2 to 5 days, a notably shorter time period than that required for the majority of detection techniques.

Humans↗
PubMed1985

Ceftriaxone against gram-negative and gram-positive bacteria: bactericidal and post-antibiotic effect.

The effect of ceftriaxone against Gram-negative and Gram-positive strains of different clinical isolates has been compared to that of other cephalosporins such as cefuroxime, cefoxitin and cefotaxime. Cefotaxime and ceftriaxone have a notably higher activity against Enterobacteriaceae than cefuroxime and cefoxitin. If ceftriaxone activity is compared to cefotaxime activity, it may be seen that the former shows a stronger action against Pseudomonas, Proteus rettgeri, Enterobacter and Serratia. Against Staphylococcus aureus and enterococci the four antibiotics show a low level of activity. The effect of a microorganism's temporary contact with ceftriaxone was tested by a method whereby the antibiotic was removed with an ion-exchanging resin. Ceftriaxone shows rapid bactericidal activity against sensitive bacteria and if it is used at concentrations slightly higher than MIC, as in vivo against bacteria of average sensibility, we notice a 10-18 h bacteriostatic effect during which a prevalence of filamentous shapes of gram-negative bacteria is observed.

Cefotaxime↗
PubMed1985

Resistance to beta-lactam antibacterial agents in hospitals.

In recent years, due to the frequent use of antimicrobial agents, strains resistant to antibiotics have been seen with increasing frequency among hospital isolates. We have compared the susceptibility to different beta-lactam drugs of Pseudomonas spp. and Staphylococcus aureus strains, isolated during a 10-yr period (1974-1984) from pathological specimens of different units of Spedali Civili of Brescia Medical School. We have also analyzed the plasmid DNA profile of representative Staphylococcus aureus strains isolated in 1984.

Anti-Bacterial Agents↗
PubMed1984

In vitro antibacterial activity of thiamphenicol.

This in vitro study of thiamphenicol activity against 247 strains of Gram-positive and 195 strains of Gram-negative pathogenic bacteria showed no significant changes from past activity. Of the 442 strains involved, thiamphenicol proved: - Effective (MIC = less than or equal to 0.5-4 micrograms/ml) against 131 strains, mostly streptococci, pneumococci and enterococci. - Moderately effective (MIC = 8-64 micrograms/ml) against 252 strains, mostly staphylococci, Salmonella, Citrobacter, K. pneumoniae, Enterobacter, E. coli and Proteus. - Ineffective (MIC = 64 micrograms/ml) against 59 strains, mostly Proteus, E. coli and K. pneumoniae. Against 23 strains of Neisseria gonorrhoeae, thiamphenicol generally proved as effective as penicillin G and cefuroxime and more effective than spectinomycin.

Bacteria↗
PubMed1984

Resistance to inactivating bacterial enzymes of different cephalosporins and in vitro activity.

The susceptibility in vitro of aerobic bacteria to cefoxitin and other cephalosporins was determined. The strains were isolated from clinical specimens during 1979 and 1983. The in vitro activity of cefoxitin and other antibiotics against anaerobic bacteria was investigated. The resistance of 5 cephalosporins to inactivating enzymes of bacterial origin was compared.

Bacteria, Anaerobic↗
PubMedDate not supplied

A multicentre study to evaluate the effect of sulbactam/ampicillin combination on anaerobic micro-organisms.

Ampicillin combined with the beta-lactamase inhibitor sulbactam was compared with ampicillin alone, cefoxitin and metronidazole against 569 clinical strains of anaerobic organisms. The strains included 289 species of Bacteroides, 160 strains of Clostridium and 120 strains of various species of Streptococcus/Peptostreptococus, Fusobacterium, Veillonella, Eubacterium, Bifidobacterium, Actinomyces and Propionibacterium. Sulbactam/ampicillin was as effective as cefoxitin and metronidazole against all anaerobic species tested, inhibiting more than 90% of strains at the breakpoints (16, 32 and 32 mg/l, respectively). Sulbactam/ampicillin was also significantly more active than ampicillin against strains of Bacteroides, the minimal inhibitory concentration being at least four-fold lower. In contrast, the activity of the combination did not differ from that of ampicillin alone against Fusobacterium species and Gram-positive rods and cocci.

Ampicillin↗