Biomedical subjects

G V Carbonell

Publications and source records attributed to G V Carbonell.

4 recordsLinked to original sources

PubMed1997

Detection of cytotoxic activity on Vero cells in clinical isolates of Serratia marcescens.

Cytotoxin production was studied in 60 Serratia marcescens strains isolated from hospitalized patients. Association of cytotoxic activity with serotype, source of isolation and presence of plasmids was also evaluated. Thirteen of the 60 S. marcescens strains produced a cytotoxic effect on Vero cells. These strains were isolated from distinct clinical sources and classified into seven different serotypes (O1:H7; O4:NM; O10:NT; O19:NM; O6,14:H4; O6,14:NM and O6,14:H1). No relationship was observed between cytotoxic activity and clinical source or serotypes of the strains. Plasmids from five cytotoxin-producing S. marcescens strains were transferred to E. coli K12/711. The transconjugants did not exhibit cytotoxicity, indicating that the cytotoxic effect is not plasmid-mediated among these strains. Although a cytotoxic activity was demonstrated in filtrates of some S. marcescens strains, further studies should be performed to assess the role of this toxin in pathogenesis.

Animals↗

PubMed1996

Culture conditions affect cytotoxin production by Serratia marcescens.

Cytotoxins have been implicated in the pathogenesis of bacterial infections. In this study, the influence of different culture conditions was evaluated on cytotoxin production of Serratia marcescens. Parameters such as culture media, incubation temperature, starting pH of culture medium, aeration, anaerobiosis, carbon sources, iron concentration in he culture media, and release of cell-bond toxin by polymyxin B were investigated. The data suggest that this cytotoxin is predominantly extracellular and is not induced by iron limitation. Aerobic culture with shaking resulted in higher cytotoxicity than static aerobic or anaerobic culture. Bacteria grown in glucose, sucrose or galactose were more cytotoxic than those grown in inositol or maltose. The culture conditions that were identified as optimal for cytotoxin production by Serratia marcescens were incubation temperature ranging from 30 to 37 degrees C, in medium adjusted pH 8.5, with shaking. This work will contribute to further studies on the identification of this cytotoxic activity.

Bacterial Toxins↗

PubMed1992

Virulence factors in Serratia marcescens: cell-bound hemolysin and aerobactin.

1. A total of 60 nosocomial isolates of Serratia marcescens were screened for the presence of markers related to virulence, i.e., cell-bound hemolysin and production of siderophore aerobactin. 2. No aerobactin-producing strains were found, and the incidence of cell-bound hemolysin was 97%. 3. Hemolysin-positive (58 strains) and hemolysin-negative (2 strains) Serratia marcescens showed the same LD50 (3 x 10(7) bacteria) in a test of virulence for mice. 4. These results indicate that cell-bound hemolysin is not a main factor of virulence for mice in Serratia marcescens.

Animals↗

PubMedDate not supplied

[Plasmid size determination using 3 methods].

Analysis of bacterial plasmid profiles has been shown to be very important in epidemiological studies, especially those involving outbreaks of nosocomial infections. The molecular weight size of unknown plasmids is determined by comparing their band pattern obtained in agarose gel electrophoresis with those obtained with plasmids that have been used as molecular weight or size standards. In this study, we determined the size of plasmids present in clinical samples of Enterobacter cloacae comparing their electrophoresis mobility with seven plasmids of known size, using three different mathematical methods. For plasmids with molecular weight ranging from 2 kb to 100 kb. The most accurate determinations were obtained by power-function. Analyses using the exponential variables obtained with these plasmids were accurate for two types of plasmids, those with size ranging from 50 kb to 100 kb and those with size ranging from 2 kb to 30 kb. We also observed discrepancies among the methodologies described, including one used by a computer software designed for calculating the size of plasmids DNA.

Algorithms↗