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Biomedical subjects

G G Grassi

Publications and source records attributed to G G Grassi.

26 records · Page 2Linked to original sources
PubMed1975

Ethanol-antibiotic interactions at hepatic level.

The authors study the influence of acute and chronic ethanol intoxication on the blood levels of rifampicin and isoniazid as well of aminoglycoside antibiotics in rats. While the acute ethanol intoxication has no influence on blood levels of tested antibiotics, in the chronic inotoxication lower levels of rifampicin and higher levels of isoniazid are observed. A study was performed also to determine the influence of an acute and chronic treatment with alcohol and the avoe quoted antibiotics on the BSP elimination rate. In the acute as well as in the chronic experiments, a constant significant delay in the elimination of BSP was observed in animals treated with rafampicin either alone or associated with alcohol. Isoniazid modified the dye elimination in comparison to controls only in chronic experiments. Ethanol did not seem to have any influence on this behavior. The implications and the possible significance of these findings are discussed.

Acute Disease↗
PubMedDate not supplied

Drug-inactivating enzymes of bacteria grown in subminimal inhibitory concentrations of antibiotics.

Repeated transfers of strains of Escherichia coli and Staphylococcus aureus in medium containing subminimal inhibitory concentrations (sub-MICs) of gentamicin caused a moderate increase in the minimal inhibitory concentration of gentamicin. At the end of such transfers, E. coli K12 produced aminoglycoside phosphotransferase(3')-I [APH(3')], AND E. coli R112, which carries the plasmid-coded enzyme APH(3')-I, also produced the acetylating enzyme aminoglycoside acetyltransferase(2') [AAC(2')]. E. coli R148, which produces aminoglycoside phosphotransferase(3')-II [APH(3')-II], did not change its output of enzymes. Repeated transfers to media containing increasing concentrations of gentamicin resulted in the development of complete resistance to all aminoglycosides without the concurrent development of any demonstrable new enzyme activity. With repeated transfers in drug-free medium, a complete reversal to susceptibility to gentamicin, but not to other aminoglycosides, was obtained for strains that had previously been transferred in sub-MICs of gentamicin, whereas strains that had been transferred in increasing concentrations of gentamicin did not revert to their original sensitivity to aminoglycosides despite repeated transfers in drug-free medium.

Aminoglycosides↗
PubMedDate not supplied

[Resistance to antibiotics of bacteria involved in respiratory infections (author's transl)].

The present status of resistance to antibiotics of bacteria involved in respiratory infections is reviewed. Schematically it can outlined as follows. Streptococcus B-haemolyticus as well as Pneumococcus did not change their sensitivity to penicillin, but some strains are now resistant to tetracycline. Streptococcus viridans, Enterococcus and H. influenzae did not change substantially their sensitivity to antibiotics. Staphylococcus aureus is the bacterial species that always poses some problems with regard to antibiotic resistance. Due to the selection of strains penicillinase-producing because of the large use of penicillin, the most part of clinical isolates of staphylococci is now resistant to penicillin. In addition an increased number of strains resistant to the other antibiotics has been registered as soon as they has been introduced in therapy. The resistant strains spread in a particularly rapid way in hospital. The introduction in therapy of penicillinase-resistant penicillins constituted a remarkable advance in therapy of staphylococcal infection. However, there is now a growing number of indications about the emergence of methicillin resistant strains of staphylococci. On the other hand it must be recalled that since 1960 a marked reduction of incidence and mortality in severe staphylococcal infections has been noted. Incidence and mortality of respiratory infections due to Gram-negative bacilli is augmented particularly in connection with a larger use of immunosuppressive and antineoplastic therapies, of particular surgical or reanimation procedures, of intensive courses of antibiotic therapy etc. Emergence of Pseudomonas, Proteus, Serratia, Providencia, etc. infections poses many difficult problems of chemotherapy since these species are scarcely sensitive to antibiotics. Carbenicillin, cephalosporins, sisomicin, tobramycin, amikacin are the more recent drugs that alone or in combination may offer some chances of success in this field.

Anti-Bacterial Agents↗