(41/3442) Reconstruction of a historical genealogy by means of STR analysis and Y-haplotyping of ancient DNA.
Archaeological excavations in St Margaretha's church at Reichersdorf, Germany, in 1993 led to the discovery of eight skeletons, so far assumed to be of the Earls of Konigsfeld, who used the church as a family sepulchre over a period of seven generations from 1546 to 1749. DNA-based sex testing and analysis of autosomal short tandem repeat systems (STR) was carried out to confirm the assumption of kinship. Since five of the individuals were determined as males, analysis of Y-specific STRs seemed feasible. A comparison of Y-haplotypes revealed that one individual could not be linked to the Konigsfeld patrilineage, an observation supported by autosomal STR evidence. Two individuals typed as females posed an identification problem, since supposedly only male members of the family were buried in St Margaretha's. Nevertheless, these individuals could tentatively be identified as members of the House of Konigsfeld through genetic fingerprinting. (+info)
(42/3442) Phenotypic and genotypic typing of food and clinical isolates of Enterobacter sakazakii.
Enterobacter sakazakii, designated a unique species in 1980, has been implicated as the causative organism in a rare but severe form of neonatal meningitis. Dried infant formula milk has been identified as a potential source of the organism. E. sakazakii isolates from dried infant formula available in Canada and clinical isolates obtained from Canadian hospital culture collections were characterised by phenotypic (biotype and antibiograms) and genotypic (ribotyping, random amplification of polymorphic DNA and pulsed-field gel electrophoresis) methods. Three biotypes and four antibiogram patterns were observed in the 18 isolates examined. Ribotyping with the Dupont Riboprinter microbial identification system divided the 18 isolates into 10 ribotypes. Three isolates from the same hospital had indistinguishable ribotyping patterns although each was isolated in a different year, as did three food isolates from one company. Pulsed-field gel electrophoresis (PFGE) and random amplification of polymorphic DNA (RAPD) profiles indicated minor differences between the isolates that were indistinguishable by ribotyping. PFGE (with the restriction endonucleases Xba1 and Spe1) and RAPD gave discrete patterns that enabled easy comparison of E. sakazakii isolates, with a high degree of discrimination. The discriminatory index showed RAPD and PFGE were shown to be the most discriminatory typing schemes for E. sakazakii, followed by ribotyping, biotyping and antibiograms. (+info)
(43/3442) Multiple types of Legionella pneumophila serogroup 6 in a hospital heated-water system associated with sporadic infections.
Five sporadic cases of nosocomial Legionnaires' disease were documented from 1989 to 1997 in a hospital in northern Italy. Two of them, which occurred in a 75-year-old man suffering from ischemic cardiopathy and in an 8-year-old girl suffering from acute leukemia, had fatal outcomes. Legionella pneumophila serogroup 6 was isolated from both patients and from hot-water samples taken at different sites in the hospital. These facts led us to consider the possibility that a single clone of L. pneumophila serogroup 6 had persisted in the hospital environment for 8 years and had caused sporadic infections. Comparison of clinical and environmental strains by monoclonal subtyping, macrorestriction analysis (MRA), and arbitrarily primed PCR (AP-PCR) showed that the strains were clustered into three different epidemiological types, of which only two types caused infection. An excellent correspondence between the MRA and AP-PCR results was observed, with both techniques having high discriminatory powers. However, it was not possible to differentiate the isolates by means of ribotyping and analysis of rrn operon polymorphism. Environmental strains that antigenically and chromosomally matched the infecting organism were present at the time of infection in hot-water samples taken from the ward where the patients had stayed. Interpretation of the temporal sequence of events on the basis of the typing results for clinical and environmental isolates enabled the identification of the ward where the patients became infected and the modes of transmission of Legionella infection. The long-term persistence in the hot-water system of different clones of L. pneumophila serogroup 6 indicates that repeated heat-based control measures were ineffective in eradicating the organism. (+info)
(44/3442) Molecular and epidemiological characterization of vaginal Saccharomyces cerevisiae isolates.
Although vaginitis caused by Saccharomyces cerevisiae is extremely rare, in recent years we have experienced an increasing frequency of S. cerevisiae isolation from the vaginas of fertile-age women. In order to investigate the epidemiology of these vaginal infections, a total of 40 isolates of S. cerevisiae derived from symptomatic and asymptomatic women were characterized by two DNA typing approaches, named ribosomal DNA (rDNA) hybridization and Ty917 hybridization, based on the Southern blotting technique. After transfer, the polymorphic DNA restriction fragments were hybridized with the entire repeat of S. cerevisiae rDNA for one method and with the entire sequence of the Ty917 retrotransposon for the other. After elaboration with computer-assisted analysis, the results of each method showed that Ty917 hybridization is endowed with a discriminatory power higher than that of rDNA hybridization. With the Ty917 hybridization method, all of the S. cerevisiae isolates tested appeared very heterogeneous, with the exception of those collected from individual patients with recurrent vaginitis. This allowed us to exclude a possible common source of infection while the high relatedness among S. cerevisiae sequential isolates from recurrent-vaginitis patients could suggest a pattern of relapse rather than frequent reinfection. (+info)
(45/3442) Inactivation of Mycobacterium tuberculosis for DNA typing analysis.
DNA fingerprinting analysis of Mycobacterium tuberculosis is used for epidemiological studies and the control of laboratory cross-contamination. Because standardized procedures are not entirely safe for mycobacteriology laboratory staff, the paper proposes a new technique for the processing of specimens. The technique ensures the inactivation of M. tuberculosis before DNA extraction without the loss of DNA integrity. The control of inactivated cultures should be rigorous and should involve the use of two different culture media incubated for at least 4 months. (+info)
(46/3442) Usefulness of spoligotyping To discriminate IS6110 low-copy-number Mycobacterium tuberculosis complex strains cultured in Denmark.
Mycobacterium tuberculosis complex strains cultured in Denmark have been analyzed by IS6110 restriction fragment length polymorphism (RFLP) on a routine basis from 1992 and onwards. Due to the influx of immigrants with tuberculosis, the number of strains harboring only one to five copies of IS6110 has increased steadily. Since the discriminatory power of IS6110 fingerprinting for such strains is poor, we have performed additional genotyping of all low-copy-number strains by the recently described PCR-based method known as spoligotyping. A total of 311 clinical strains were typed: 14 Mycobacterium bovis BCG, 48 M. bovis, and 249 M. tuberculosis strains. Spoligotyping correctly differentiated M. bovis and M. bovis BCG from M. tuberculosis strains, but it did not differentiate M. bovis from M. bovis BCG. All M. bovis BCG strains exhibited identical spoligotype patterns. The discriminatory power of spoligotyping of low-copy-number M. tuberculosis strains was higher than that of IS6110 fingerprinting. Based on RFLP typing solely, 83% of the low-copy-number M. tuberculosis strains were found to form part of a cluster, and 75% were found to form a cluster on the basis of spoligotyping. When the two techniques were combined, the amount of clustering decreased to 55%. The combination of these two techniques might be valuable in studying the epidemiology of M. tuberculosis strains harboring few copies of the IS6110 element. (+info)
(47/3442) A multidrug-resistant tuberculosis microepidemic caused by genetically closely related Mycobacterium tuberculosis strains.
IS6110 DNA fingerprinting was used to characterize an outbreak of multidrug-resistant tuberculosis in 21 individuals (17 males and 4 females) living in or roaming among four distantly separated areas in the Czech Republic. The restriction fragment length polymorphism (RFLP) analysis separated the collected Mycobacterium tuberculosis strains into group A, including 14 patients with six IS6110 copies, and group B, with 7 patients displaying highly similar RFLP patterns but with two additional IS6110 bands. A switch from pattern A to pattern B was observed in one patient, and the subsequent detection of subclone B in seven more individuals has been explained by the instability of DNA genotypes caused by transposition of IS6110 elements. (+info)
(48/3442) Genomic relatedness of Chlamydia isolates determined by amplified fragment length polymorphism analysis.
The genomic relatedness of 19 Chlamydia pneumoniae isolates (17 from respiratory origin and 2 from atherosclerotic origin), 21 Chlamydia trachomatis isolates (all serovars from the human biovar, an isolate from the mouse biovar, and a porcine isolate), 6 Chlamydia psittaci isolates (5 avian isolates and 1 feline isolate), and 1 Chlamydia pecorum isolate was studied by analyzing genomic amplified fragment length polymorphism (AFLP) fingerprints. The AFLP procedure was adapted from a previously developed method for characterization of clinical C. trachomatis isolates. The fingerprints of all C. pneumoniae isolates were nearly identical, clustering together at a Dice similarity of 92.6% (+/- 1.6% standard deviation). The fingerprints of the C. trachomatis isolates of human, mouse, and swine origin were clearly distinct from each other. The fingerprints of the isolates from the human biovar could be divided into at least 12 different types when the presence or absence of specific bands was taken into account. The C. psittaci fingerprints could be divided into a parakeet, a pigeon, and a feline type. The fingerprint of C. pecorum was clearly distinct from all others. Cluster analysis of selected isolates from all species revealed groups other than those based on sequence data from single genes (in particular, omp1 and rRNA genes) but was in agreement with available DNA-DNA hybridization data. In conclusion, cluster analysis of AFLP fingerprints of representatives of all species provided suggestions for a grouping of chlamydiae based on the analysis of the whole genome. Furthermore, genomic AFLP analysis showed that the genome of C. pneumoniae is highly conserved and that no differences exist between isolates of respiratory and atherosclerotic origins. (+info)
Download our free solidary book to support research on VHL disease