Aims: To evaluate the utility of random amplification of polymorphic DNA (RAPD) technique for routine practice in public health laboratories for epidemiological studies of Vibrio cholerae O1 isolates. Materials and Results: Seventy-nine strains were examined by PCR for the toxin genes (ctx A, zot and ace), virulence-associated genes (tcp A and tox T) and RAPD sequences. Except for one strain (no. 1123) from the Amazonas State, all the strains analysed carried the genes ctx A, zot, ace, tcp A and tox T. RAPD fingerprinting revealed variability but no correlation with serotype, biotype or geographical origin of the isolates was found. Conclusion: A standardized RAPD method does not enable the establishment of a pattern data bank for the identification of V. cholerae O1 strains. Significance and Impact of the Study: The simplicity and discriminative capacity of this technique make it useful for detecting genetic diversity among micro-organisms from a defined group or for outbreak investigation.
Aims:
To investigate genetic diversity among
Staphylococcus aureus and to delineate the geographical distribution of the strains found.
Methods and Results:
RAPD‐PCR and ribotyping‐PCR were employed for the characterization of
Staph. aureus isolates from bovine and nosocomial origin. Among the strains, five to nine groups were distinguished by RAPD‐PCR, depending on which primer was used, while ribotyping‐PCR distinguished seven ribotypes.
Conclusions, and Significance and Impact of the Study:
These results demonstrate the genetic heterogeneity of the strains studied, and the large dissemination of some clones throughout different regions and hosts, findings that may allow the monitoring of
Staph. aureus infections.
Introduction: Plague is an acute, infectious zoonotic disease, primarily of wild rodents and their fleas, that affects humans and other mammals. In Brazil, several plague foci are located in the northeast region. Plague surveillance based on monitoring of rodents was discontinued in 2007, and the current information on rodent populations is unsatisfactory. Our purpose was to update the information on rodents and other small mammals in plague foci in northeastern Brazil.
Methodology: Nine surveys in the historically most important northeastern plague areas were conducted in 2013-2015.
Results: In this study, 393 animals (13 rodent and four marsupial species) were entrapped. The plague bacterium Yersinia pestis was not detected in tissue sample cultures from the 225 animals that were analyzed. Eighty sera samples were analyzed for anti-F1 antibodies by hemagglutination (HA) and protein A ELISA tests, and all were negative, except for one marsupial, Monodelphis domestica, which was HA positive.
Conclusions: Qualitative and quantitative differences in the animal populations were observed in the areas surveyed, and the antibody positive marsupial indicated that plague continues to circulate in the wild.
Yersinia pestis, the etiologic agent of plague, harbors three well-characterized plasmids: pFra (90-110kb), pYV (70 kb) and pPst (9.5 kb). Furthermore, some extra-cryptic DNA bands have been observed in a number of wild strains from several foci of the world. Additional bands have also been reported in Brazilian strains. Looking for any relationship among these cryptic DNA bands and the three-prototypical plasmids, we analyzed twelve strains displaying different plasmid content. The DNA bands were hybridized by southern blot with probes directed at the genes caf1, lcrV and pla located respectively on the plasmids pFra, pYV and pPst. The probes were constructed by PCR amplification and labeled with digoxigenin. The Pla probe hybridized with its target (pPst) and with bands of about 35 kb suggesting some homology among them. The Caf1 probe hybridized with the target (pFra) as well as with higher bands. The LcrV also hybridized with the target (pYV) and both with the bands higher than pFra and the bands between pFra and pYV. These results suggest that the large-cryptic bands could represent some rearrangement, open circular or linearized forms of the pFra and pYV plasmids.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.