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M L Quilici

Publications and source records attributed to M L Quilici.

9 recordsLinked to original sources
PubMed1996

Ribotyping of Chryseobacterium meningosepticum: its use as an epidemiological tool and its correlation with serovars.

Chryseobacterium meningosepticum (basonym, Flavobacterium meningosepticum King 1959) is associated with neonatal meningitis and is isolated from normal and immunocompromised adults. AAF-labelled Escherichia coli 16 + 23S rRNA was used as a probe for ribotype analysis of 92 clinical isolates from tracheal exsudate, blood culture, cerebrospinal fluid, urine and pus. The 92 isolates belonged to the 15 described serovars of C. meningosepticum, and included 21 strains isolated during an outbreak in an intensive care unit, all belonging to serovar G. Three restriction endonucleases, EcoRI, HindIII and PstI, were selected for use in ribotyping after preliminary experiments. Epidemiologically unrelated isolates were discriminated by ribotyping and could be classified into 48 ribotypes according to the hybridization banding patterns obtained after restriction with the three enzymes. Strains which were not discriminated by combined ribotype analysis belonged to the same serovar, and were of identical geographic origin. In one case, analysis with an additional enzyme, PvuII, was necessary for separating strains from two different serovars. However, three strains from different serovars (two isolated from the same place and one elsewhere within eight years) showed the same combined ribotype. Analysis of the rRNA gene patterns revealed 6 different patterns for clinical isolates of the outbreak, suggesting unrelated sources of infection. In three patients, isolation of C. meningosepticum with different combined ribotypes suggested superinfection. Ribotyping enabled differentiation between isolates belonging to the same serovar as well as between isolates of different serovars and provided a useful molecular epidemiological tool for the study of C. meningosepticum. Combined ribotype analysis with several restriction endonucleases increased the discriminating power of the method. However, there was only a partial correlation between serovars and the extent of DNA relatedness.

Adult↗
PubMed1988

BamHI restriction endonuclease analysis of Yersinia ruckeri plasmids and their relatedness to the genus Yersinia 42- to 47-megadalton plasmid.

The plasmid profile and BamHI restriction pattern of 17 sorbitol-negative and 1 sorbitol-positive French Yersinia ruckeri strain of the American type strain were studied. The 17 sorbitol-negative strains and the American strain harbored a 62-megadalton (MDa) plasmid with an identical BamHI restriction pattern. Southern hybridization indicated that this 62-MDa plasmid is common among these various strains. The sorbitol-positive strain had four plasmid bands (70, 62, 32, and 25 MDa), and there was no comigration of the DNA fragments of these cleaved plasmids with the fragments of the 62-MDa plasmid. Hybridization of these restricted plasmids with the common 62-MDa plasmid showed a weak DNA homology. The Y. ruckeri plasmid (62 MDa) had a different molecular weight than the virulence plasmid (42 to 47 MDa) of the genus Yersinia, and they had different BamHI restriction patterns. Furthermore, no sequence of the Y. ruckeri plasmid DNA was recognized after Southern hybridization when the 47-MDa plasmid of Y. enterocolitica was used as a probe.

Animals↗
PubMedDate not supplied

Role of the virulence-associated plasmids of Yersinia enterocolitica on its immunogenicity against Y. pestis.

Forty-two strains selected from various serovars of Yersinia enterocolitica were studied for their ability to induce cross-protection against Y. pestis. Only primo-infected mice (i.v.) with inocula prepared from strains of Y. enterocolitica belonging to serovars 0:3, 0:9 and 0:5, 27 harbouring a 47-Mdal virulence-associated plasmid were resistant to Y. pestis. The spontaneously cured (plasmid-less) derivatives of these strains had lost the capacity to induce this cross-immunity.

Animals↗
PubMedDate not supplied

Lack of correlation between plasmid-encoded outer membrane proteins and virulence of Yersinia enterocolitica.

When various strains of Yersinia enterocolitica belonging to serovars 0:1,3, 0:3, 0:5,27, 0:9 and 0:Tacoma harbouring 44- to 47-Md plasmids, or their spontaneously cured isogenic pairs, were inoculated (i. v., with standardized inocula) into Swiss female mice, the kinetics of bacterial survival in the spleen were followed, revealing inoculum destruction within 15 days. With both strains Ye8081 and WA (0:8, harbouring a 42-Md plasmid), the kinetics of bacterial growth ended in the death of mice. The early spleen bacterial uptake was the same with all strains studied, whether plasmid-harbouring or plasmid-less derivatives. In this study, virulent strain Ye8081 and both low-virulent IP383 and Ye9576 were shown to synthesize antigenically related outer membrane polypeptides plasmid-encoded at 37 degrees C and previously considered as virulence determinants.

Animals↗