TY  - JOUR
A1  - Knapp, S.
A1  - Hacker, Jörg
A1  - Jarchau, T.
A1  - Goebel, W
T1  - Large, Unstable Inserts in the Chromosome Affect Virulence
Properties Of Uropathogenic Escherichia coli 06 Strain 536
N2  - The hemolytic, uropathogenic Escherichia coli 536 (06:K15:H31) contains two inserts in its chromosome (insert I and insert II), both of which carried hly genes, were rather unstable, and were deleted spontaneously with a frequen~y of 10-3 to 10-4• These inserts were not found in the chromosome of two nonhemolytic E. coli strains, whereas the chromosomal ~equences adjacent to these inserts appeared tobe again homologous in the uropathogenic and two other E. coü strains. Insert I was 75 kilobases in size and was ftanked at both ends by 16 base pairs (bp) (TTCGACTCCTGTGATC) which were arranged in direct orientation. For insert I it was demonstrated that deletion occurred by recombination between the two 16-bp ftanking sequences, since mutants lacking this insert still carried a single copy of the 16-bp sequence in the chromosome. 8oth inserts contained a functional hemolysin determinant. However, the loss of the inserts not only atfected the hemolytic phenotype bot led to a considerable reduction in serum resistance and the loss of mannose-resistant hemagglutination, caused by the presence of S-type funbriae (sja). lt is shown that the Sfa-negative phenotype is due to a block in transcription of the sfa genes. Mutants of strain 536 which lacked both inserts were entirely avirulent when tested in several animal model systems.
KW  - Infektionsbiologie
Y1  - 1986
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-59402
ER  - 
TY  - JOUR
A1  - Ott, M.
A1  - Hacker, Jörg
A1  - Schmoll, T.
A1  - Jarchau, T.
A1  - Korhonen, T. K.
A1  - Goebel, W
T1  - Analysis of the genetic determinants coding for the S fimbrial adhesin (sfa) in different Escherichia coli strains causing meningitis or urinary tract infections
N2  - Recently we have described the molecular cloning of the genetic determinant coding for the S-fimbrial adhesin (Sfa), a sialic acid-recognizing pilus frequently found among extraintestinal Eschenchili coli isolates. Fimbriae from the resulting Sfa + E. coli K-12 clone were isolated, and an Sfa-specific antiserum was prepared. Western blots indicate that S fimbriae isolated from different uropathogenic and meningitis-associated E. coli strains, including 083:Kl isolates, were serologically related. The Sfa-specific antibodies did not cross-react with P fimbriae, but did cross-react with FlC fimbriae. Furthermore the sja+ recombinant DNAs and some cloned s/a-flanking regions were used as probes in Southem experiments. Chromosomal DNAs isolated from 018:Kl and 083:Kl meningitis strains with and without S fimbriae and from uropathogenic 06:K + strains were hybridized against these sfa-specific probes. Only one copy of the sfa determinant was identified on the chromosome of these strains. No sfa-specific sequences were observed on the chromosome of E. coli K-12 strains and an 07:Kl isolate. With the exception of small alterations in the sfa-coding region the genetic determinants for S fimbriae were identical in uropathogenic 06:K + and meningitis 018:Kl and 083:Kl strains. The sfa determinant was also detected on the chromosome of Kl isolates with an Sfa-negative phenotype, and specific cross-hybridization signals were visible after blotting against FlC-specific DNA. In addition homology among the different strains was observed in the sfa-flanking regions.
KW  - Infektionsbiologie
Y1  - 1986
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-59432
ER  -