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Biomedical subjects

F Grimont

Publications and source records attributed to F Grimont.

At least 91 records · Page 5Linked to original sources

rRNA gene restriction patterns of Haemophilus influenzae biogroup aegyptius strains associated with Brazilian purpuric fever.

The rRNA gene restriction patterns of 92 isolates of Haemophilus influenzae biogroup aegyptius, associated with conjunctivitis or Brazilian purpuric fever in the State of São Paulo, Brazil, were studied with 16 + 23S rRNA from Escherichia coli as a probe. All strains were classified into 15 patterns. Isolates from Brazilian purpuric fever cases were seen only in patterns 3 (most frequently) and 4 (rarely), whereas isolates from conjunctivitis were found in all 15 patterns. The study demonstrated that rRNA from E. coli can serve as a probe for molecular epidemiology.

Autoradiography↗

DNA probe specific for Legionella pneumophila.

A procedure for preparing a DNA probe to be used in the specific detection of Legionella pneumophila by dot or colony hybridization has been devised. When total DNA from L. pneumophila was used as a radioactive probe, cross-hybridization occurred with DNA from many other species belonging to various families (including Legionellaceae, Enterobacteriaceae, Pseudomonadaceae, and Vibrionaceae). Cross-hybridizing restriction fragments in L. pneumophila ATCC 33152 DNA were identified on Southern blots. When unlabeled DNA from strain ATCC 33152 was cleaved by endonuclease BamHI, the DNA fragments cross-hybridizing with the labeled DNA from all of the other species and genera tested (or with Escherichia coli 16 + 23 S RNA) had a size of 21.4 and 16.2 kilobase pairs (major bands) and 28.0, 12.8, and 10.1 kilobase pairs (minor bands). BamHI restriction fragments of L. pneumophila DNA deprived of the cross-hybridizing fragments were pooled and used as a probe for the detection of L. pneumophila. This probe proved to be specific for L. pneumophila in colony and dot hybridization. It can potentially be used for the detection of L. pneumophila in clinical and water samples. The procedure described can be readily applied to the preparation of probes specific for phylogenetically isolated bacterial species other than L. pneumophila.

Base Sequence↗

["Serratia marcescens" in neonatology: epidemiology of a hazard (author's transl)].

A case of meningitis, caused by Serratia marcescens in a 6-day old newborn triggered a search for Serratia in the Neonatology ward. Fifteen out of 38 newborns were found fecal carriers of S. marcescens. The source of S. marcescens was found in flasks containing almond oil with 1% cetyltrimethylammonium bromide used for skin care. All strain of S. marcescens belonged to pigmented biotype A6a and serotype 014 : H10. The spread of S. marcescens was controlled by heat sterilizing and renewing twice a week the almond oil flasks. Means of control of contamination sources are discussed.

Dermatologic Agents↗

Compatible results obtained from biotyping and serotyping in Serratia marcescens.

The correspondence between complete serotype and biotype (P.A.D. Grimont and F. Grimont, J. Clin. Microbiol. 8:73-83, 1978) of 474 Serratia marcescens strains was studied. Of 127 serotypes, 70 were represented by two or more strains of the same serotype belonged to one biotype. However, for 91% of serotypes, strains of the same serotype belonged to one biogroup--i.e., a group of closely related biotypes. Biogroups are A1 (A1a, A1b); A2/6 (A2a, A2b, A6a, A6b); A3 (A3a, A3b, A3c, A3d); A4 (A4a, A4b); A5/8 (A5, A8a, A8b, A8c); and TCT (TCT, TT). Only two serotypes were composed of a mixture of pigmented and nonpigmented biogroups. Pigmented biogroups (A1 and A2/6) were otherwise differentiated from nonpigmented biogroups (A3, A4, A5/8, and TCT) by serotyping. Some biogroups preferentially occurred in some O serogroups: A4 in 01; A2/6 in O6, O8, and O14; and A3 in O9, O12, and O15. Three H serogroups were found to be biochemically homogeneous: H1, H7, and H20 were respectively and uniquely composed of biogroups A4, TCT, and A3. A square matrix of O versus H serogroups, with the corresponding biogroup for each O X H combination, was used for comparisons between O groups and between H groups. Identical patterns of biogroups were shown by serogroups O6, O8, and O14. Taxonomical, ecological, and practical consequences of these findings are discussed.

Carbon↗

Biotyping of Serratia marcescens and its use in epidemiological studies.

A Serratia marcescens biotyping system using eight carbon sources (benzoate, DL-carnitine, m-erythritol, 3-hydroxybenzoate, 4-hydroxybenzoate, lactose, D-quinate, and trigonelline), a tetrathionate reduction test, production of prodigiosin, and horse blood hemolysis was derived from a recent numerical taxonomic study (Grimont et al., J. Gen. Microbiol. 98:39-66, 1977). A total of 98.6% of 2,210 isolates from various sources could be assigned to 1 of 19 biotypes. Distribution and spread of 1,088 S. marcescens isolates throughout 13 clinical departments of Pellegrin Hospital (Bordeaux, France) were studied from 1968 through 1975. Except for one that colonized the intestinal tract of newborns, the six pigmented biotypes were seldom isolated. Each of the 13 nonpigmented biotypes showed a particular pattern of distribution and spread. The usefulness of S. marcescens biotyping was shown by relating several isolates recovered from patients and their inanimate environment and by pointing out the possible existence of infections or colonizations by two unrelated biotypes. S. marcescens strains isolated from the natural environment (water) are usually pigmented, and their biotypes are uncommon in hospitals. Biotyping can, therefore, be of help in epidemiological and ecological surveys.

Bacteriological Techniques↗

Taxonomy of the genus Serratia.

One hundred and fifty-six strains of Serratia and related bacteria including representatives of Enterobacter liquefaciens, Enterobacter cloacae, Enterobacter aerogenes, Erwinia carotovora, Erwinia chrysanthemi, Erwinia herbicola and Erwinia nimipressuralis were studied using 223 morphological, physiological, biochemical and carbon source utilization tests. The results were subjected to computer analysis. At the 80% similarity level all strains, except two, grouped into eight phenons representing: (A) Serratia marcescens with the neotype CCM303 (ATCCI3880); (B) S. marinorubra with the monotype NCTC10912 (ATCC27614); (CI) S. liquefaciens with the type ATCCI4460; (C2) S. plymuthica with the monotype CCM640 (ATCC183); (D) Erwinia herbicola with the neotype of Enterobacter agglomerans NCTC9381; (E) Enterobacter cloacae with the neotype NCTCI0005 and Erwinia nimipressuralis; (F) Erwinia carotovora with the type ATCC495, Erwinia atroseptica and Erwinia chrysanthemi; (G) Klebsiella mobilis with the neotype NCTCI0006. At the 70% similarity level the phenons formed two groups: (A, B, CI, C2) and (D, E, F, G). The following conclusions were drawn. (I) There are three species of enterobacteria producing prodigiosin: S. marcescens, S. plymuthica and S. marinorubra. (2) There are four species of Serratia, one colourless (S. liquefaciens). (3) Subphenons (biovars) are described within the four species of Serratia. (4) Non-pigmented wild-type strains of S. marcescens can generally be differentiated from pigmented strains by characters other than pigmentation, because subphenons are homogeneous with respect to pigmentation. This survey raised some problems of nomenclature because old descriptions could be found that could loosely fit the present phenons. Comparison with an authentic culture was considered to be the most objective way of identifying these phenons with earlier named species.

Bacteriological Techniques↗

Caprylate-thallous agar medium for selectively isolating Serratia and its utility in the clinical laboratory.

A defined agar medium (hereinafter designated caprylate-thallous [CT5 agar) containing 0.01% yeast extract, 0.1% caprylic (n-octanoic) acid, and 0.025% thallous sulfate is highly selective for all Serratia species and effectively discriminates against most non-Serratia strains likely to be in the same habitats. The selectivity of CT agar is demonstrated by the very high efficiency of colony formation (mean, 80.7% of that on a nonselective complex medium) on CT agar by known Serratia strains and the very low efficiency of colony formation (close to zero) on CT agar by bacterial strains known not to be Serratia. The utility of this medium in actual clinical laboratory practice is demonstrated by the more rapid and higher recovery of Serratia on this selective medium as compared to conventional procedures of in-tandem runs of 513 consecutive urine, feces, and sputum specimens. Pigmented and nonpigmented Serratia strains deliberately added to fecal specimens can be selectively and quantitatively recovered on CT agar. CT agar compares favorably with, or in some cases is an improvement over, other selective media which have been recommended for isolating Serratia. This selective CT agar medium could be quite useful in ecological surveys, especially those related to hospital-acquired infections.

Agar↗

Ewingella americana gen.nov., sp.nov., a new Enterobacteriaceae isolated from clinical specimens.

We propose the name Ewingella gen.nov. for a new group in the Enterobacteriaceae. Ewingella is phenotypically distinct from all other groups of Enterobacteriaceae. The members of this genus are lipase- and deoxyribonuclease-negative; Voges-Proskauer-positive; lysine-, ornithine- and arginine-decarboxylase-negative; anaerogenic; they produce acid from glucose in the presence (and absence) of iodoacetate, but fail to produce acid from L-arabinose, melibiose, raffinose, D-sorbitol or sucrose. DNA-relatedness studies (S1-nuclease method) showed that the 10 Ewingella strains studied form a single DNA-hybridization group which is less than 21% related to other members of the Enterobacteriaceae. This single DNA-hybridization group is named Ewingella americana sp. nov. The type strain of E. americana is CDC 1468-78 (= ATCC 33852 = CIP 8194). Although the 10 strains of E. americana were isolated from clinical sources in the United States, the clinical significance of these organisms is not known.

Base Composition↗

Genomic identification of meat Lactobacilli as Lactobacillus sake.

Eighty-four strains of homofermentative lactobacilli isolated from meat showed a great diversity in carbohydrate fermentation patterns. DNA-DNA hybridization (S1 nuclease method) showed 13 representative strains to constitute a homogeneous genomic group 65 to 82% related to Lactobacillus sake ATCC 15521, with delta Tm values below 1.5 degree C. The description of L. sake is emended.

Carbohydrate Metabolism↗

rRNA gene restriction patterns of Legionella species: a molecular identification system.

A total of 28 species of Legionella could be differentiated by rRNA gene restriction patterns generated after cleavage of total DNA with either EcoRV or HindIII restriction endonucleases, and hybridization of fragments with 32P-labelled Escherichia coli 16 + 23S rRNA. Different species gave different fragment patterns. When several isolates of a species were tested, the patterns obtained were often identical. However, more than one pattern was often observed when more than one serotype was considered. The method should be useful for the identification of all species of Legionella including those exhibiting immunological cross-reactions.

DNA Restriction Enzymes↗

Clonal diversity of Vibrio cholerae O1 evidenced by rRNA gene restriction patterns.

The rRNA gene restriction patterns of 89 Vibrio cholerae O1 isolates from different geographic origins were studied. The probe was Escherichia coli 16 + 23S rRNA labelled with "ECL Gene detection system". A total of 17 rRNA gene restriction patterns were observed after BglI cleavage. Four patterns (B1 to B4) were only given by biotype cholerae (14 strains studied). Thirteen patterns (B5 to B17) were only given by biotype El Tor (75 strains studied). There was no correlation between serotypes and rRNA gene restriction patterns. This study provides arguments that (1) strains of biotypes cholerae and El Tor are different clones, (2) a cholera pandemic is not a single world-wide epidemic (due to a single clone) but rather a simultaneous occurrence of several epidemics (several clones involved), and (3) epidemic waves of biotype El Tor could be due to the emergence of new clones.

Cholera↗

Palindromic unit highly repetitive DNA sequences exhibit species specificity within Enterobacteriaceae.

Palindromic units (PU, or REP for repetitive extragenic palindrome) constitute a family of DNA sequences of 40 nucleotides which is highly repeated in the genome of Escherichia coli. We analysed the presence of PU sequences in 99 different bacterial genomes by cross-hybridization. When PU sequences were used as a probe, only DNA from Enterobacteriaceae closely related to E. coli exhibited an appreciable hybridization signal: Shigella sonnei, Shigella boydii, Salmonella enteritica serotype Typhimurium, Citrobacter freundii and Levinea malonatica. Furthermore, these bacteria could be divided into two groups which corresponded to a slight difference in their PU sequence: the E. coli group includes S. sonnei and S. boydii; the S. enteritica serotype Typhimurium group includes C. freundii and L. malonatica.

Blotting, Southern↗

Nucleotide sequences of 16S rRNA from ten Serratia species.

Comparison of 16S ribosomal ribonucleic acid (rRNA) sequences has emerged as a powerful tool for bacterial phylogeny. However, earlier studies often only included one or a few species per genus, and it is not sure whether the rRNA sequences could discriminate closely related species. The genus Serratia is composed of ten species, some being up to 60% related by DNA hybridization. The reverse transcriptase/primer extension method was used to determine 1,492 to 1,509 nucleotides in each of ten Serratia 16S rRNA sequences. All rRNA sequences determined were unique. The phylogenetic tree obtained with the neighbour-joining method showed a cluster of Serratia species distinct from both Escherichia coli and Proteus vulgaris. S. fonticola--whose position in the genus Serratia is questioned--was clearly included in the Serratia branch and grouped within the psychrophilic Serratia species. Variable regions in the Serratia rRNA molecules were identified and could serve as the basis for a specific probe design.

Base Sequence↗

Ribotyping of Streptococcus agalactiae strains isolated from vaginas of asymptomatic women.

One hundred and eleven strains of Streptococcus agalactiae isolated from vaginas of asymptomatic women were characterized by determination of restriction length polymorphism profiles of rDNA regions (rDNA RFLP patterns) and serotyping. Thirty-five different PstI rDNA RFLP patterns were identified. Half of the strains fell into only seven of these 35 groups. No correlation between serotypes and rDNA RFLP patterns was found. These results indicate that (i) the genetic diversity of the S. agalactiae species is relatively limited and (ii) determination of rDNA RFLP patterns can be used as a typing system only in conjunction with serotyping.

Bacterial Typing Techniques↗