Abstract
Objectives The aims of this study were to determine the resistance level of a bla CTX-M-37 -carrying Enterobacter cloacae isolate from Mongolia, to analyse kinetic parameters of the purified enzyme and to compare the genetic environment of the gene. Methods Minimum inhibitory concentrations (MICs) were determined using the Clinical and Laboratory Standards Institute (CLSI) agar dilution method. Purified CTX-M-37 enzyme was used to determined kinetic parameters. The genetic environment of the blaCTX-M-37 gene in E. cloacae was compared with a Kluyvera cryocrescens isolate. Results The E. cloacae isolate showed relatively low-level resistance to cefotaxime (MIC = 16 mg/L) compared with a CTX-M-3-producing strain (MIC = 256 mg/L), and CTX-M-37 had a lower k cat /K m value for cefotaxime (2.0 μM −1 s −1 ) compared with CTX-M-3 (3.5 μM −1 s −1 ), possibly due to Asn114Asp substitution. The bla CTX-M-37 gene in the E. cloacae isolate was carried on a conjugative plasmid and was associated with an ISEcp1 element containing the −35 and −10 putative promoter sequences TTGAAA and TACAAT, respectively, unlike in the K. cryocrescens isolate. Conclusions The CTX-M-37-producing E. cloacae isolate showed relatively low-level resistance to cefotaxime and the purified enzyme had lower kinetic parameters as the result of Asn114Asp substitution. Presence of an ISEcp1 element and putative promoters upstream of the bla CTX-M-37 gene in E. cloacae, but not in the K. cryocrescens isolate, indicated their roles in mobilisation and expression of the gene.
| Original language | English |
|---|---|
| Pages (from-to) | 3-7 |
| Number of pages | 5 |
| Journal | Journal of Global Antimicrobial Resistance |
| Volume | 10 |
| DOIs | |
| Publication status | Published - 2017 Sep 1 |
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All Science Journal Classification (ASJC) codes
- Microbiology
- Immunology and Allergy
- Immunology
- Microbiology (medical)
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Genetic and biochemical characterisation of CTX-M-37 extended-spectrum β-lactamase from an Enterobacter cloacae clinical isolate from Mongolia. / Lee, Kyungwon; Yong, DongEun; Jeong, Seokhoon; Tulgaa, Khosbayar; Docquier, Jean Denis; Rossolini, Gian Maria; Chong, Yunsop.
In: Journal of Global Antimicrobial Resistance, Vol. 10, 01.09.2017, p. 3-7.Research output: Contribution to journal › Article
TY - JOUR
T1 - Genetic and biochemical characterisation of CTX-M-37 extended-spectrum β-lactamase from an Enterobacter cloacae clinical isolate from Mongolia
AU - Lee, Kyungwon
AU - Yong, DongEun
AU - Jeong, Seokhoon
AU - Tulgaa, Khosbayar
AU - Docquier, Jean Denis
AU - Rossolini, Gian Maria
AU - Chong, Yunsop
PY - 2017/9/1
Y1 - 2017/9/1
N2 - Objectives The aims of this study were to determine the resistance level of a bla CTX-M-37 -carrying Enterobacter cloacae isolate from Mongolia, to analyse kinetic parameters of the purified enzyme and to compare the genetic environment of the gene. Methods Minimum inhibitory concentrations (MICs) were determined using the Clinical and Laboratory Standards Institute (CLSI) agar dilution method. Purified CTX-M-37 enzyme was used to determined kinetic parameters. The genetic environment of the blaCTX-M-37 gene in E. cloacae was compared with a Kluyvera cryocrescens isolate. Results The E. cloacae isolate showed relatively low-level resistance to cefotaxime (MIC = 16 mg/L) compared with a CTX-M-3-producing strain (MIC = 256 mg/L), and CTX-M-37 had a lower k cat /K m value for cefotaxime (2.0 μM −1 s −1 ) compared with CTX-M-3 (3.5 μM −1 s −1 ), possibly due to Asn114Asp substitution. The bla CTX-M-37 gene in the E. cloacae isolate was carried on a conjugative plasmid and was associated with an ISEcp1 element containing the −35 and −10 putative promoter sequences TTGAAA and TACAAT, respectively, unlike in the K. cryocrescens isolate. Conclusions The CTX-M-37-producing E. cloacae isolate showed relatively low-level resistance to cefotaxime and the purified enzyme had lower kinetic parameters as the result of Asn114Asp substitution. Presence of an ISEcp1 element and putative promoters upstream of the bla CTX-M-37 gene in E. cloacae, but not in the K. cryocrescens isolate, indicated their roles in mobilisation and expression of the gene.
AB - Objectives The aims of this study were to determine the resistance level of a bla CTX-M-37 -carrying Enterobacter cloacae isolate from Mongolia, to analyse kinetic parameters of the purified enzyme and to compare the genetic environment of the gene. Methods Minimum inhibitory concentrations (MICs) were determined using the Clinical and Laboratory Standards Institute (CLSI) agar dilution method. Purified CTX-M-37 enzyme was used to determined kinetic parameters. The genetic environment of the blaCTX-M-37 gene in E. cloacae was compared with a Kluyvera cryocrescens isolate. Results The E. cloacae isolate showed relatively low-level resistance to cefotaxime (MIC = 16 mg/L) compared with a CTX-M-3-producing strain (MIC = 256 mg/L), and CTX-M-37 had a lower k cat /K m value for cefotaxime (2.0 μM −1 s −1 ) compared with CTX-M-3 (3.5 μM −1 s −1 ), possibly due to Asn114Asp substitution. The bla CTX-M-37 gene in the E. cloacae isolate was carried on a conjugative plasmid and was associated with an ISEcp1 element containing the −35 and −10 putative promoter sequences TTGAAA and TACAAT, respectively, unlike in the K. cryocrescens isolate. Conclusions The CTX-M-37-producing E. cloacae isolate showed relatively low-level resistance to cefotaxime and the purified enzyme had lower kinetic parameters as the result of Asn114Asp substitution. Presence of an ISEcp1 element and putative promoters upstream of the bla CTX-M-37 gene in E. cloacae, but not in the K. cryocrescens isolate, indicated their roles in mobilisation and expression of the gene.
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U2 - 10.1016/j.jgar.2017.03.007
DO - 10.1016/j.jgar.2017.03.007
M3 - Article
VL - 10
SP - 3
EP - 7
JO - Journal of Global Antimicrobial Resistance
JF - Journal of Global Antimicrobial Resistance
SN - 2213-7165
ER -