Biomedical subjects
U Fabio
Publications and source records attributed to U Fabio.
Keratomycosis with an unusual etiology (Rhodotorula glutinis): a case report.
A case of deep keratomycosis with isolation of Rhodotorula glutinis is discussed. Keratoplasty, done immediately, prevented panophthalmitis and cured the patient. The etiology and pathogenesis of fungal keratitis is examined.
Antibiotic resistance in foodborne Listeria.
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Streptococcus mutans: classification in bacteriocin-types.
A sample of S. mutans bacteriocins was studied to obtain a useful outline of strain typing since their synthesis has proved stable and not under plasmidial control. The inhibiting effectiveness against 9 oral streptococci and the sensitivity of mutacins produced by 49 S. mutans strains to heat, chloroform and proteasic activity were evaluated. On the basis of our results the producing strains are classified into five different types. We examine the possibility of obtaining a useful typing with bacteriocins and we discuss the choice of the most suitable number of indicators to arrange the strains in a limited cluster number for epidemiological purpose, or to classify freshly isolated S. mutans strains into bacteriocin-types.
Restriction endonuclease analysis of chromosomal DNA from Listeria monocytogenes strains.
Restriction endonuclease analysis of chromosomal DNA was applied to thirteen Listeria monocytogenes strains alongside the more conventional typing methods of serotyping and phage typing. The organisms were isolated from cases of sporadic listeriosis (nine strains); from an occasional nosocomial cluster (two strains); and from food samples (two strains). Purified DNAs were digested with EcoRI restriction endonuclease, and restriction fragments separated by electrophoresis. Restriction patterns correlated well with phage patterns, but also allowed typing of the phage-untypable strains. DNA fingerprinting appears to be a potentially helpful tool for epidemiological investigations of listeric infections, particularly when phage typing fails to determine the identity or diversity of the isolates.
Carbamimidothioic acid phenylmethyl ester salts and their N,N'-tetramethyl derivatives as possible antimicrobial agents.
A series of carbamimidothioic acid phenylmethyl ester salts and their N,N'-tetramethyl derivatives were synthesized, many of which exert an interesting inhibiting action on Gram-positive and Gram-negative bacteria and also on fungi. This activity is noteworthy in view of the large number of strains antagonized; the (3,4,5-trichlorophenyl) methyl ester chloride of carbamimidothioic acid appeared to be the best term of the series. The possible influence on this activity of decomposition kinetics to the corresponding mercapto-derivatives was investigated and compared with that of a series of N,N'-tetramethyl derivatives of previously studied carbamimidothioic acid phenyl ester salts.
Cross-infection with Listeria monocytogenes confirmed by DNA fingerprinting.
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Isolation of Pasteurella multocida from human clinical specimens: first report in Italy.
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In vitro antibacterial activity of enoxacin, a new pyridonecarboxylic acid.
The antibacterial activity of enoxacin was determined against 1015 strains of Gram-positive and Gram-negative bacteria, mainly freshly isolated from clinical specimens. The minimum inhibitory concentrations (MIC 50-75-90) were determined in comparison to three commonly used antibiotics: ampicillin, cefotaxime and gentamicin. Enoxacin has shown a broad spectrum of action and antibacterial activity in general higher that than of three currently available antibiotics. The antibacterial activity seems similar to that of other quinolones of second generation.
Production of bacteriocin-like substances by human oral streptococci.
A sample of human streptococci (mainly Streptococcus mutans species) from dental plaques was examined in order to evaluate the production frequency and activity spectrum of bacteriocin-like substances (mutacins). 89% of the 55 Streptococcus mutans strains produced substances with a wide spectrum of antibacterial activity. The bacteriocins produced showed a marked inhibitory activity against Gram-positive bacteria. Among the Gram-negative species tested, only Neisseria sicca was inhibited by 25% of Streptococcus mutans strains. Also, 16 strains belonging to oral streptococci other than Streptococcus mutans, were examined for their inhibitory capacity against the same indicator. The authors stress the importance of mutacins production in oral ecology and Streptococcus mutans pathogenicity.
[Antimicrobial activity of derivatives of 1,2,4-benzothiadiazine-1,1-dioxide. VIII].
The antimicrobial activity of a series of fluoro derivatives of benzothiadiazine and sulfonamides was studied. The compounds tested can be grouped as: a) 3-alkylmercapto derivatives of 6-trifluoromethyl-1,2,4-benzothiadiazine-1,1-dioxide (III leads to VI); the 3-mercapto precursor (VII) and the related 3-picolinic salt (VIII); b) 3-trifluoromethyl derivatives of 1,2,4-benzothiadiazine-1,1-dioxide and of its benzene substituted derivatives (IX leads to XVI); c) trifluoroacetylaminobenzenesulfonamides (XVII leads to XXV). Two of the 3-alkylmercapto compounds [(V) and (VI)] showed marked inhibitory activity against some strains of Staphylococcus, Streptococcus and Diplococcus. None of the compounds tested proved active against Gram-negative schizomycetes (genera Salmonella, Shigella, Escherichia, Proteus, Pseudomonas, Enterobacter, Klebsiella, Serratia, Yersinia, Providencia) or against yeasts (Candida).
[The incidence and variation of transferable antibiotic-resistance in Salmonella strains isolated in Modena in the years 1975-1977 (author's transl)].
The antibiotic-resistance of 450 strains of Salmonella isolated by the Microbiology Unit of the hospital of Modena during the years 1975-1977 was examined. During the study, the following antibiotics were assayed: ampicillin, kanamycine, tetracycline, chloramphenicol, streptomycin, sulfonamides, trimethoprim, tobramycin, gentamicin and nalidixic acid. The transfer capacity of antibiotic-resistance was measured by the double conjugation of E. coli K-12. During the period studied, a remarkable reduction was noted in those strains with multiple resistance (3 or more elements) decreasing from 72.9% in 1975 to 23.5% in 1977. These phenomena are due to the decrease of the serum-type wien during the years under study. Antibiotic-resistance demonstrated itself most frequently to streptomycin and tetracycline; and chloramphenicol-resistance showed the highest transfer capacity (97.2%).
[Antimicrobial effect of derivatives of 1,2,4-benzothiadiazin-1,1-dioxide. VII].
Series of alkyl derivatives of the following have been prepared: 5,7-dichloro- [compounds (II leads to V)], 6-methyl- [compounds (VI leads to IX)] and 6-methoxy-3-mercapto-1,2,4-benzothiadiazine-1,1-dioxide [compounds (X leads to XIII)]. The products were tested for antimicrobial activity. Studies were also made of the corresponding 3-mercapto precursors (XIV, XV, XVI) and the relative 3-picolinium salts (XVII, XVIII, XIX) and also of the 3-picolinium salts of 6-chloro-, 7-chloro- and 6,7-dichloro-3-mercapto-1,2,4-benzothiadiazine-1,1-dioxide (XX, XXI, XXII). Some of the 3-alkylmercapto compounds, and especially the 5,7-dichloro derivative, inhibited various strains of Gram-positive bacteria of the genus Staphylococcus, while the same substances proved much less effective against the genera Streptococcus and Diplococcus. Antimicrobial activity appeared to be influenced by the length of the alkyl chain as well as by the nature and position of the substituents on the benzene ring. The compounds proved inactive against the Gram-negative schizomycetes (Salmonella, Shigella, Escherichia, Proteus, Pseudomonas. Enterobacter, Klebsiella, Serratia, Yersinia, Providencia) and against yeasts (Candida) with the exception of compound (V) which showed slight bacteriostatic action against three strains of Candida albicans.
[Antimicrobial action of 1,2,4-benzothiadiazine-1,1-dioxide derivatives. V].
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[Antimicrobial action of 1,2,4-benzothiadiazine-1,1-dioxide derivatives. VI].
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Repeated monitoring of Au-SH antigen in blood donors of Reggio Emilia.
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[Antimicrobial activity of 1,2,4-benzothiadiazine-1,1-dioxide derivatives. II].
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