A Multiresistant Clone of Shiga Toxin-Producing Escherichia coli O118:[H16] Is Spread in Cattle and Humans over Different European Countries

Autor: Lothar Beutin, Heinrich Maidhof, Thomas S. Whittam, Beatriz Guerra, Hany M. Elsheikha, Sascha Abbas
Rok vydání: 2002
Předmět:
Zdroj: Applied and Environmental Microbiology. 68:5834-5842
ISSN: 1098-5336
0099-2240
Popis: Multiresistant Shiga toxin-producing Escherichia coli (STEC) O118:H16 and O118 nonmotile strains (designated O118:[H16]) were detected by examination of 171 STEC isolates for their antimicrobial sensitivity. Of 48 STEC O118:[H16] strains, 98% were resistant to sulfonamide, 96% were resistant to streptomycin, 79% were resistant to kanamycin, 75% were resistant to tetracycline, 67% were resistant to ampicillin, 60% were resistant to chloramphenicol, 48% were resistant to trimethoprim, and 10% each were resistant to gentamicin and nalidixic acid. Nalidixic acid resistance and reduced susceptibility to ciprofloxacin were associated with the mutation gyrA LEU-83 . The STEC O118:[H16] strains were found to belong to a single genetic clone as investigated by multilocus enzyme electrophoresis and by multilocus sequence analysis of E. coli housekeeping genes. The STEC O118:[H16] strains originated from humans and cattle and were isolated in seven different countries of Europe between 1986 and 1999. Strains showing multiresistance to up to eight different antimicrobials predominated among the more recent STEC O118:[H16] strains. The genes in parentheses were associated with resistance to kanamycin ( aphA1-Ia ), chloramphenicol ( catA1 ), tetracycline [ tet (A)], and ampicillin ( bla TEM-1 ). Class 1 integrons containing sulI (sulfonamide resistance), aadA1a (streptomycin resistance), or dfrA1 (trimethoprim resistance) -aadA1a gene cassettes were detected in 28 strains. The bla TEM-1b gene was present in 18 of 21 strains that were examined by nucleotide sequencing. Class 1 integrons and bla TEM genes were localized on plasmids and/or on the chromosome in different STEC O118:[H16] strains. Hybridization of Xba I-digested chromosomal DNA separated by pulsed-field gel electrophoresis revealed that bla TEM genes were integrated at different positions in the chromosome of STEC O118:[H16] strains that could have occurred by Tn 2 insertion. Our data suggest that strains belonging to the STEC O118:[H16] clonal group have a characteristic propensity for acquisition and maintenance of resistance determinants, thus contrasting to STEC belonging to other serotypes.
Databáze: OpenAIRE