TY - JOUR
T1 - Characterisation of plasmids encoding CTX-M-3 extended-spectrum β-lactamase from Enterobacteriaceae isolated at a university hospital in Taiwan
AU - Liu, S. Y.
AU - Su, L. H.
AU - Yeh, Y. L.
AU - Chu, C.
AU - Lai, J. C.
AU - Chiu, C. H.
PY - 2007/4
Y1 - 2007/4
N2 - CTX-M-3 is the most common extended-spectrum β-lactamase produced by Enterobacteriaceae in Taiwan. The present study was conducted to characterise the genetic environment surrounding blaCTX-M-3. A total of 11 ceftriaxone-resistant isolates were studied: Escherichia coli (n = 4), Klebsiella pneumoniae (n = 5) and Salmonella enterica serotypes Anatum (SA831R) and Potsdam (SC72). Molecular methods used included polymerase chain reaction, sequencing, DNA-DNA hybridisation, conjugation, physical mapping and restriction fragment length polymorphism (RFLP) analysis. All isolates examined carried blaCTX-M-3 on large plasmids (>70 kb). The resistance plasmids of the two Salmonella and two K. pneumoniae strains (KP104 and KP116) were confirmed to be conjugative in vitro. RFLP analysis indicated that the plasmids were different. Physical mapping also revealed the difference between the two Salmonella plasmids, pSA831R (82 kb) and pSC72 (74 kb). An insertion sequence, ISEcp1, was found upstream of each blaCTX-M-3 gene. However, sequencing of downstream regions of the bla genes showed two different patterns: the presence of orf477 in pSA831R and of orf1-mucA in pSC72, pKP104 and pKP116. IncI1-type oriT and nikA sequences were present in the plasmids of all the clinical isolates tested, except S. Anatum. Different blaCTX-M-3-carrying plasmids were identified among the enterobacteria studied. The presence of ISEcp1 in all isolates may be associated with the widespread resistance among Enterobacteriaceae. Although the plasmids were not identical, they appeared to belong to the same incompatibility group (IncI1-like plasmids), suggesting that they are genetically related but may have evolved divergently over time.
AB - CTX-M-3 is the most common extended-spectrum β-lactamase produced by Enterobacteriaceae in Taiwan. The present study was conducted to characterise the genetic environment surrounding blaCTX-M-3. A total of 11 ceftriaxone-resistant isolates were studied: Escherichia coli (n = 4), Klebsiella pneumoniae (n = 5) and Salmonella enterica serotypes Anatum (SA831R) and Potsdam (SC72). Molecular methods used included polymerase chain reaction, sequencing, DNA-DNA hybridisation, conjugation, physical mapping and restriction fragment length polymorphism (RFLP) analysis. All isolates examined carried blaCTX-M-3 on large plasmids (>70 kb). The resistance plasmids of the two Salmonella and two K. pneumoniae strains (KP104 and KP116) were confirmed to be conjugative in vitro. RFLP analysis indicated that the plasmids were different. Physical mapping also revealed the difference between the two Salmonella plasmids, pSA831R (82 kb) and pSC72 (74 kb). An insertion sequence, ISEcp1, was found upstream of each blaCTX-M-3 gene. However, sequencing of downstream regions of the bla genes showed two different patterns: the presence of orf477 in pSA831R and of orf1-mucA in pSC72, pKP104 and pKP116. IncI1-type oriT and nikA sequences were present in the plasmids of all the clinical isolates tested, except S. Anatum. Different blaCTX-M-3-carrying plasmids were identified among the enterobacteria studied. The presence of ISEcp1 in all isolates may be associated with the widespread resistance among Enterobacteriaceae. Although the plasmids were not identical, they appeared to belong to the same incompatibility group (IncI1-like plasmids), suggesting that they are genetically related but may have evolved divergently over time.
KW - Antimicrobial resistance
KW - Conjugation
KW - Enterobacteriaceae
UR - http://www.scopus.com/inward/record.url?scp=33847372868&partnerID=8YFLogxK
U2 - 10.1016/j.ijantimicag.2006.11.013
DO - 10.1016/j.ijantimicag.2006.11.013
M3 - 文章
C2 - 17275265
AN - SCOPUS:33847372868
SN - 0924-8579
VL - 29
SP - 440
EP - 445
JO - International Journal of Antimicrobial Agents
JF - International Journal of Antimicrobial Agents
IS - 4
ER -
