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Biomedical subjects

F Gavini

Publications and source records attributed to F Gavini.

At least 37 records · Page 2Linked to original sources

Susceptibilities to antibiotics and antiseptics of new species of the family Enterobacteriaceae.

One hundred and sixty-nine strains of new species of the family Enterobacteriaceae, isolated mainly from the environment, were tested to determine their susceptibilities to 13 antibiotics and 4 antiseptics or disinfectants. All the species were susceptible to aminoglycosides, doxycycline, and trimethoprim but were resistant to chloramphenicol. Susceptibility to beta-lactams varied more among the strains. However, all the strains were cefotaxime susceptible, apart from some Buttiauxella agrestis strains for which MICs were greater than 256 micrograms/ml. The antiseptic MBCs were similar to those published elsewhere for species of the Enterobacteriaceae of clinical origin. No resistance to chlorhexidine was observed. On the other hand, the environmental strains presented a greater resistance to active chlorine than did the reference strains.

Anti-Bacterial Agents↗

Evaluation of autoscan-4 for identification of members of the family Enterobacteriaceae.

A study was performed to compare the Autoscan-4 (MicroScan, Inc., Mahwah, N.J.) with conventional biochemical methods for identifying clinical isolates of the family Enterobacteriaceae. The Autoscan-4 yielded correct identification of 95.4% of the isolates at the species level and 98.4% at the genus level. Only one misidentification was observed. The identification of both common and less-common isolates of Enterobacteriaceae makes this system highly efficient.

Bacterial Typing Techniques↗

A rapid chemical procedure for isolation and purification of chromosomal DNA from gram-negative bacilli.

A rapid and simple method for preparing chromosomal DNA from gram-negative bacilli is presented. It is based on the alkaline (NaOH 0.03 M) lysis of cell walls. The resulting emulsion is purified by proteinase K (0.625 mg/g of wet wt), SDS, and the deproteinizing agent (chloroform isoamyl alcohol). The purity, molecular nature, and yield of DNA obtained by the present method are compared with those of DNA extracted by Marmur's procedure and a Marmur's modified procedure. We have developed and standardized this original method to isolate double-stranded DNA, free of proteins and RNA contamination and with a significantly higher yield of DNA than the two other methods. This procedure is particularly useful for strains with low growth and can be applied in every field concerned with DNA analysis.

Cell Wall↗

Nosocomial infection and colonization by Klebsiella trevisanii.

During an 18-month period we identified two cases of septicemia and 24 examples of colonization of humans by Klebsiella trevisanii. Organisms were identified using the API 20EC and API 147 assimilation galleries. Of 147 clinical isolates initially identified as K. oxytoca, 18% were found to be K. trevisanii. Tracheal aspirate was the most common source of the organism. An extensive environmental sampling survey in the rooms of 12 colonized patients revealed a possible reservoir of the organism only once (a face cloth).

Aged↗

[Taxonomic study of enterobacteria belonging or related to Escherichia coli species].

Phenetic (numerical analysis) and genetic (DNA-DNA hybridization) studies were carried out on strains belonging or related to the species Escherichia coli. They have shown the diversity of its phenotypes, by the presence of plasmidic characters (citrate+, urease+, H2S+, tetrathionate reductase+, raffinose+, and saccharose+). New strains related phenetically to E. coli are also individualized. They showed less than 30% DNA relatedness with E. coli. A new definition of E. coli is presented.

Bacteriological Techniques↗

Evaluation of Micro-ID, for identification of Enterobacteriaceae.

Micro-ID system is a new identification kit for Enterobacteriaceae which provides the identification at the species level 4 hours after primary isolation. When compared with conventional biochemical tube media, micro-ID gave a 94% agreement. Comparison of Micro-ID with Api 20 E showed a 90% agreement. A comparison of all 3 systems showed that for 90% of the time, the isolates were named the same by the all systems.

Bacteriological Techniques↗

[Study of a new group of Enterobacteriacea (group H1) related to Enterobacter cloacae strain].

A DNA-DNA hybridization study was carried out on a new group of enterobacteria (group H1) previously studied by numerical taxonomy work on the genus Enterobacter. This group showed a very high genetic homogeneity since the average relative binding ratio of nine analysed strains is equal to 91%. The taxonomic position of this group into the family of enterobacteria is discussed with the species E. cloacae (37 to 61%), K. pneumoniae (44 to 60%), K. oxytoca (57-58%), L. malonatica (syn. Citrobacter intermedius, a:46 to 54%), L. amalonatica (syn. C. intermedius, b: 51%), and the group H3 (52-61%). The group H1 is defined on phenotypic and genetic data.

DNA, Bacterial↗

[The GC content of a group of H2S- enterobacterial related to the genus Citrobacter].

The deoxyribonculeic acid (DNA) of 106 strains of Enterobacteria was analysed for the guanine + cytosine (GC) content. These strains, whose origin and principal characters are described in the text, belong to the genera Citrobacter (C. freundii H2S-) and Levinea (L. malonatica and L. amalonatica). Four other groups or classes named C.D.E. and F. could not be classified on the base of the usual phenotypic criteria. DNA from the strains of Levinea has a GC% of 50.3 to 53.3, while DNA from the strains of C. freundii H2S- has a GC% of 48.6 to 51.7. The representative values from the new classes are C, 50.9%; D, 54%; E, 52.7%; F, 49.5%. For the latter a genomic heterogeneity was shown, expressing itself as two subpopulations whose average GC% are 51.7 and 48.6 respectively. Statistical analysis of the averages give a significant individuality to these new classes.

Citrobacter↗

[Taxonomic study of enterobacteria belonging or related to the genus Klebsiella (author's transl)].

This work studies the classification, by numerical procedure, of 122 strains belonging or related to the genus Klebsiella. Four classes can be defined: J (= K. pneumoniae: 29 strains for the most isolated from human faeces), K (related to K. pneumoniae and to K. oxytoca: 24 strains isolated from water), L (related to K. pneumoniae although, tetrathionate-reductase+, m-hydrobenzoate+: 37 strains isolated from water or soil), M (= K. oxytoca: 22 strains for the most isolated from water). The importance of the origins of the strains is emphasized.

Enterobacter↗

[Taxonomic study of enterobacteria belonging or related to the genus Enterobacter (author's transl)].

The classification of 175 strains related to the genus Enterobacter has been carried out by numerical procedure, with usual biochemical and nutritional characters as shown by the utilization of substrates tested as sole sources of carbon and energy. The taxonomic position of the strains is discussed in relation to the species E. cloacae, E. hafniae, E. aerogenes, E. agglomerans and Serratia liquefaciens. By the system of data analysis used (hierarchical agregation method) five principal classes can be defined. The individualization of new classes closely bound to the diverse origins of the strains examined (human, soil, aquatic).

Enterobacteriaceae↗

Antigenic specificity of Escherichia coli alkaline phosphatase studied with monoclonal antibodies: immunological characterization of E. coli and Shigella strains.

Monoclonal antibodies (MoAb) to the alkaline phosphatase of Escherichia coli were produced from spleen cells of BALB/c mice primed with purified alkaline phosphatase of E. coli and SP2O/Ag-14 myeloma cells. Five stable clones were established. They all produced antibodies which reacted by enzyme-linked immunosorbent assay (ELISA) with alkaline phosphatase of all E. coli (25 strains) independently of their origin (drinking water, saline water, surface water, faecal or clinical origin), and with that of four Shigella species (7 strains) tested. Four of these MoAb gave a positive reaction with 52% (MoAb 4G10), 73% (MoAb 4F8, MoAb 4G6) and 89% (MoAb 3C8) of 14 other bacterial species (30 strains) studied, while one (MoAb 2E5) did not react with alkaline phosphatase of these unrelated bacterial strains and thus appeared specific for E. coli and Shigella species. This MoAb was still detectable in ascitic fluids at 1/500,000 in ELISA, and detected all E. coli strains in an indirect immunofluorescence assay at 1/100. It could therefore be used as a reagent for routine detection of E. coli in drinking water, foods or clinical specimens.

Alkaline Phosphatase↗

[Comparative immunological study of glyceraldehydephosphate dehydrogenase in Enterobacteriaceae: contribution of an anti-glyceraldehydephosphate dehydrogenase antiserum of Enterobacter intermedium].

A comparative immunological study of glyceraldehyde-3-phosphate dehydrogenase among Enterobacteriaceae was carried out with an antiserum against Enterobacter intermedium G-3-PDH. Results of immunodiffusion experiments and microcomplement fixation studies showed E. intermedium to be a homogeneous species. The genera Enterobacter and Escherichia were found to be quite heterogeneous.

Complement Fixation Tests↗

Immunological relationship among glyceraldehyde-3-phosphate dehydrogenases in the genera Enterobacter and Escherichia.

The comparative immunological study of glyceraldehyde-3-phosphate dehydrogenase (G-3-PDH) among Enterobacteriaceae carried out with an anti-Enterobacter cloacae G-3-PDH serum pointed out the large heterogeneity of the genera Enterobacter and Escherichia. The use of two-dimensional maps integrating our new data and previously acquired quantitative data confirmed these results.

Enterobacter↗

GC content of DNA of Campylobacter pylori and other species belonging or related to the genus Campylobacter.

DNA of type strain Campylobacter pylori NCTC 11637 and 32 other strains of C. pylori recovered from gastric biopsy specimens was examined by thermal denaturation for its guanine-plus-cytosine (GC) content. The GC content of strain NCTC 11637 was 35.6 mol % (standard deviation (SD) 0.3), and the GC content of the 32 other C. pylori strains ranged from 34.1 to 37.5 mol % (average value 35.2, SD 1.0). A total of 14 type strains of other Campylobacter and Wolinella species were included in this study and the results obtained were compared with those cited in the literature.

Base Composition↗