TY  - JOUR
A1  - Knapp, S.
A1  - Then, I.
A1  - Wels, W.
A1  - Michel, W.
A1  - Tschäpe, H.
A1  - Hacker, Jörg
A1  - Goebel, W
T1  - Analysis of the flanking regions from different hemolysin determinants of Escherichia coli
N2  - The haemolysin (hly) determinant of the plasmid pHly152 contains an IS2 element at 469 bp upstream of the hlyC gene. The sequence at the other (right-hand) end (RS) also shows multiple hybridization with the plasmid pHly152 and the chromosome of some Escherichia coli strains but the nucleotide sequence of this region does not reveal the typical properties of an IS element. Similar arrangements in the regions flanking the hly determinant are also found on various Hly plasmids from uropathogenic E. coli strains. Chromosomal hly determinants Iack both flanking sequences (IS2 and RS) in the immediate vicinity of the hly genes. The sequences immediately upstream of the hlyC gene have been determined from several chromosomal hly determinants and compared with the corresponding sequence of the hly determinant of the plasmid pHly152. We show that these sequences, which contain one promoter (left promoter, phlyL) in all hly determinants tested, vary considerably although common sequence elements can still be identified. In contrast, only relatively few nucleotide exchanges have been detected in the adjacent structural hlyC genes. The A + T content of the 200 bp sequence upstream of hlyC is very high (72 mol% A + T) but even the structural hly genes show a considerably higher A + T content (about 60 mol%) than the E. coli chromosome on average (50 mol% A+T) suggesting that the hly determinant may not have originated in E. coli.
KW  - Infektionsbiologie
Y1  - 1985
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-59374
ER  - 
TY  - JOUR
A1  - Ott, M.
A1  - Bender, L.
A1  - Blum, G.
A1  - Schmittroth, M.
A1  - Achtmann, M.
A1  - Tschäpe, H.
A1  - Hacker, Jörg
T1  - Virulence patterns and long range mapping of extraintestinal Escherichia coli K1, K5 and K100 isolates: Use of pulse field gel electrophoresis
N2  - A total of 127 extraintestinal Escherichia coli strains of the capsule serotypes Kl, KS, and KlOO from human and animal sources were analyzed for DNA sequences specific for the genes for various adhesins (P fimbriae fpap] and P-related sequences fprs], S fimbriae [s/a)/FlC fimbriae [foc], and type I fimbriae lfim]), aerobactin (aer), and hemolysin (hly). The expression of corresponding virulence factors was also tested. Twenty-four selected strains were analyzed by long-range DNA mapping to evaluate their genetic relationships. DNA sequences for the adhesins were often found in strains not expressing them, while strains with hemolysin and aerobactin genes usually did express them. Different isolates of the same serotype orten expressed different virulence patterns. The use of virulence-associated gene probes for Southern hybridization with genomic DNA fragments separated by pulsed-field gel electrophoresis revealed that a highly heterogeneous restriction fragment length and hybridization pattern existed even within strains of the same serotype. Long-range DNA mapping is therefore useful for the evaluation of genetic relatedness among individual isolates and facilitates the performance of .precise molecular epidemiology.
KW  - Infektionsbiologie
Y1  - 1991
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-59738
ER  -