OBJECTIVES: This study was conducted to analyse broad-spectrum cephalosporin-resistant Klebsiella oxytoca strains. METHODS: The 57 isolates studied were recovered from clinical specimens (n=23) or from rectal swabs (n=34) during a 26-month period. Antibiotic susceptibility patterns were determined using standard agar diffusion and dilution methods including the synergy test between extended-spectrum cephalosporins and clavulanic acid. ERIC-2 PCR and pulsed-field gel electrophoresis (PFGE) methods were used to study the clonal relatedness of the strains. Plasmid-mediated and chromosomal beta-lactamases were characterized by mating and specific bla gene amplification and sequencing. RESULTS: Four different antibiotic resistance patterns were identified whereas ERIC-2 PCR and PFGE revealed six main profiles. Extended-spectrum beta-lactamases (ESBLs) were found in 32 strains: TEM-7 (n=26), TEM-129 (n=1), TEM-3 (n=4), SHV-2 (n=1). The new TEM-type beta-lactamase, TEM-129, differed from TEM-7 by one mutation (Glu-104-->Lys). All TEM-7 or TEM-129 producers were genetically related. Twenty-five other strains with identical ERIC-2 PCR and PFGE profiles harboured a bla(OXY-2) gene different from the reference gene: 24 strains displayed one substitution (Ala-237-->Ser) in the KTG motif and one strain, highly resistant to ceftazidime, showed an additional substitution (Pro-167-->Ser). CONCLUSIONS: The study demonstrated that the majority of strains (n=52) harbouring the OXY-2-type beta-lactamase corresponded to two clones. The first clone (n=27) corresponded to ESBL-producing strains. The second clone (n=25) displayed extended-spectrum activity of the chromosomal beta-lactamase.
OBJECTIVES: This study was conducted to analyse broad-spectrum cephalosporin-resistant Klebsiella oxytoca strains. METHODS: The 57 isolates studied were recovered from clinical specimens (n=23) or from rectal swabs (n=34) during a 26-month period. Antibiotic susceptibility patterns were determined using standard agar diffusion and dilution methods including the synergy test between extended-spectrum cephalosporins and clavulanic acid. ERIC-2 PCR and pulsed-field gel electrophoresis (PFGE) methods were used to study the clonal relatedness of the strains. Plasmid-mediated and chromosomal beta-lactamases were characterized by mating and specific bla gene amplification and sequencing. RESULTS: Four different antibiotic resistance patterns were identified whereas ERIC-2 PCR and PFGE revealed six main profiles. Extended-spectrum beta-lactamases (ESBLs) were found in 32 strains: TEM-7 (n=26), TEM-129 (n=1), TEM-3 (n=4), SHV-2 (n=1). The new TEM-type beta-lactamase, TEM-129, differed from TEM-7 by one mutation (Glu-104-->Lys). All TEM-7 or TEM-129 producers were genetically related. Twenty-five other strains with identical ERIC-2 PCR and PFGE profiles harboured a bla(OXY-2) gene different from the reference gene: 24 strains displayed one substitution (Ala-237-->Ser) in the KTG motif and one strain, highly resistant to ceftazidime, showed an additional substitution (Pro-167-->Ser). CONCLUSIONS: The study demonstrated that the majority of strains (n=52) harbouring the OXY-2-type beta-lactamase corresponded to two clones. The first clone (n=27) corresponded to ESBL-producing strains. The second clone (n=25) displayed extended-spectrum activity of the chromosomal beta-lactamase.
Authors: Li-Kou Zou; Li-Wen Li; Xin Pan; Guo-Bao Tian; Yan Luo; Qi Wu; Bei Li; Lin Cheng; Jiu-Jing Xiao; Su Hu; Yang Zhou; Yu-Juan Pang Journal: World J Microbiol Biotechnol Date: 2012-01-26 Impact factor: 3.312
Authors: Vincent C C Cheng; Wing-Cheong Yam; Lee-Lee Tsang; Miranda C Y Yau; Gilman K H Siu; Sally C Y Wong; Jasper F W Chan; Kelvin K W To; Herman Tse; Ivan F N Hung; Josepha W M Tai; Pak-Leung Ho; Kwok-Yung Yuen Journal: J Clin Microbiol Date: 2012-02-22 Impact factor: 5.948
Authors: Amar Cosic; Eva Leitner; Christian Petternel; Herbert Galler; Franz F Reinthaler; Kathrin A Herzog-Obereder; Elisabeth Tatscher; Sandra Raffl; Gebhard Feierl; Christoph Högenauer; Ellen L Zechner; Sabine Kienesberger Journal: Front Microbiol Date: 2021-07-02 Impact factor: 5.640