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Biomedical subjects

F Scazzocchio

Publications and source records attributed to F Scazzocchio.

11 recordsLinked to original sources
PubMed1989

Effect of slime production on the antibiotic susceptibility of isolates from prosthetic infections.

The antibacterial activity of 6 antibiotics towards 10 gram-positive and 6 gram-negative glycocalyx-producing strains, has been evaluated by employing a method which partially simulates the in vivo colonization of prosthetic devices. The results showed that routine antibiotic sensitivity tests are not predictive about the response of the glycocalyx-embedded bacteria, and that prophylaxis may be useful with ofloxacin and clindamycin, before placing a prosthetic device. Once bacterial colonization had already occurred, however, none of the tested antibiotics was able to eradicate the sessile bacterial form. The minimum bactericidal concentration (MBC) values, indeed, were much higher than those determined on the planktonic form, and were much higher than serum and tissue levels that can be reached in vivo.

Anti-Bacterial Agents↗
PubMed1988

Plasmid "curing" by some recently synthetized 4-quinolone compounds.

Nalidixic acid and two recently synthetized 4-quinolones eliminated F'lac and R-plasmids from E. coli at concentrations of one half or one quarter of the minimum inhibitory concentration (MIC). Two of the three plasmids tested were cured by all derivatives, although with different frequencies. Pefloxacin was the most effective compound compared with the other quinolones and nalidixic acid the least active.

Escherichia coli↗
PubMed1988

Inhibition of plasmid conjugation by some recently synthetized 4-quinolone compounds.

Four fluoroquinolones (norfloxacin, ciprofloxacin, ofloxacin, and pefloxacin) were compared with nalidixic acid for their inhibitory effect on conjugal plasmid transfer. The inhibition was observed in mating experiments using various combinations of drugs at subinhibitory concentrations and 3 different plasmids in the E. coli k12 genetic background. Fluoroquinolones inhibited plasmid transfer to a greater extent than nalidixic acid. Ofloxacin and pefloxacin were consistently the most active agents, causing 90 to 100% inhibition of plasmid transfer in all mating systems studied.

Anti-Infective Agents↗
PubMed1988

In vitro activity of pefloxacin compared with five other quinolones on nalidixic acid-resistant proteae species.

The in vitro activity of pefloxacin, a new fluoroquinolone, was compared with that of 5 other quinolone compounds (nalidixic and pipemidic acids, norfloxacin, ciprofloxacin, and ofloxacin) against 416 strains of Proteae spp. isolated from urine specimens of hospitalized patients with acute urinary tract infections (UTI). Ciprofloxacin was the most active agent. Norfloxacin, ofloxacin, and pefloxacin were similarly active against Proteus strains (MIC90 = 0.39 microgram/ml). Against Providencia spp. pefloxacin and norfloxacin showed similar activity (MIC90 = 3.12 micrograms/ml). There is minimal discrepancy between minimum inhibitory concentrations and minimum bactericidal concentrations exhibited by the quinolones for all urinary tract pathogens tested. Our in vitro studies indicate that pefloxacin is an active antimicrobial agent and suggest that it will prove useful in the treatment of complicated urinary tract infections due to nalidixic acid-resistant Proteae spp.

Anti-Infective Agents↗
PubMed1987

On the formation of a dicloxacillin-p-hydroxymercuribenzoate suicide complex mediated by beta-lactamase I from Bacillus cereus.

p-Hydroxymercuribenzoate is a non-competitive inhibitor of beta-lactamase I from Bacillus cereus and also, after preliminary preincubation, an inactivator of the enzyme. Submitted to the simultaneous action of PCMB plus dicloxacillin, the enzyme completely loses its activity. Extensive dialysis can restore the enzymatic activity only if preincubation had been carried out with either PCMB or dicloxacillin but not if both inhibitors had been simultaneously present. Mercaptoethanol protects the enzyme from the action of PCMB, but not from the severe inactivation caused by dicloxacillin-PCMB mixtures. All these data suggest the formation of a complex between PCMB and the acyl-enzyme intermediate generated upon hydrolysis of the beta-lactam bond of dicloxacillin.

Bacillus cereus↗
PubMed1984

Inhibition of beta-lactamase production in gram-positive and gram-negative strains by sub-inhibitory concentrations of nalidixic acid.

We found it of interest to try to determine a microbiological parameter for the effects that sub-inhibitory doses of a chemotherapeutic agent may have on bacteria. To this end, the antibacterial activity of nalidixic acid was analyzed and our attention was directed to evidence of the production of beta-lactamase by 60 strains. The tests carried out showed that sub-inhibitory concentrations of nalidixic acid, from 2 to 64 times lower than the MIC (minimum inhibitory concentrations), were able to inhibit production of penicillinases in the 14 strains of Staphylococcus spp. tested, while only in 7 of the 21 strains of Gram-negative bacteria. Strains from our collection of beta-lactamase producing bacteria were analyzed, and our results confirmed that nalidixic acid inhibits plasmidic and chromosomic beta-lactamases.

Gram-Negative Bacteria↗
PubMedDate not supplied

[Antibiotic and metal resistance in "Escherichia coli" strains isolated from the environment and from patients (author's transl)].

The incidence and the patterns of the antibiotic and metal resistance in 106 strains of Escherichia coli isolated from ground waters, used also as drinking water supply (sample A), was studied in comparison with the resistance behaviour in the 104 strains of the same microorganism isolated from non hospitalized patients (sample P). Significant differences between the percentage of resistant strains in the two examined samples were found for some of the antibiotics and the metals tested (ampicillin, streptomycin, kanamycin, mercury and zinc) while non statistically significant differences were found for gentamicin, tetracyclin, nalidixic acid and cadmium. From the high percentages of the resistant strains in the environmental sample (up to 44.3% for tetracyclin) we may deduce that also the ground waters, especially if used as drinking water, contribute to the spread of the resistant bacteria. The patterns of the antibiotic multiresistances in the strains isolated from patients and from ground waters do not differ greatly and this strengthens the hypothesis that resistance to antibiotics has been acquired by Escherichia coli strains before reaching the ground waters.

Drug Resistance, Microbial↗