Abstract
Thirty-four clinical isolates of Serratia marcescens nonsusceptible to cefotaxime were collected from a medical center in middle Taiwan. Confirmatory tests for extended-spectrum β-lactamases (ESBLs) by cefotaxime and ceftazidime ± clavulanic acid using Etest ESBL Screen identified only one ESBL producer; the remaining 33 isolates revealed nondeterminable results, because of off-scale minimum inhibitory concentration (MIC) levels for cefotaxime ± clavulanic acid. Agar microdilution method using broader MIC ranges confirmed 21 ESBL-producers and one non-determinable result, achieving a highly predicting value compared to golden standard by PCR and DNA sequencing analysis, which identified 22 (65%) isolates containing bla CTX-M-3 genes. Only one strain carried concurrent CTX-M-3 and SHV-5 conferring high-level MICs to both cefotaxime (128 μg/mL) and ceftazidime (64 μg/mL). Other enzymatic mechanisms, such as chromosome-encoded AmpC including a novel SRT-2 enzyme, may confer resistance to cefotaxime on the remaining 12 isolates without ESBL bla genes. Thus, it is unreliable to predict the resistance mechanism by antibiogram, and current Etest ESBL Screen tests. Our study highlights expanding efforts to detect ESBLs in S. marcescens are urgently needed in Taiwan.
| Original language | English |
|---|---|
| Pages (from-to) | 125-129 |
| Number of pages | 5 |
| Journal | Diagnostic Microbiology and Infectious Disease |
| Volume | 49 |
| Issue number | 2 |
| DOIs | |
| Publication status | Published - Jun 2004 |
| Externally published | Yes |
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ASJC Scopus subject areas
- Infectious Diseases
- Immunology and Allergy
- Virology
- Parasitology
- Microbiology
- Immunology
- Applied Microbiology and Biotechnology
Cite this
Survey of CTX-M-3 extended-spectrum β-lactamase (ESBL) among cefotaxime-resistant Serratia marcescens at a medical center in middle Taiwan. / Wu, Lii Tzu; Tsou, Mei Fen; Wu, Hwa Jene; Chen, Hui E.; Chuang, Yin Ching; Yu, Wen-Liang.
In: Diagnostic Microbiology and Infectious Disease, Vol. 49, No. 2, 06.2004, p. 125-129.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Survey of CTX-M-3 extended-spectrum β-lactamase (ESBL) among cefotaxime-resistant Serratia marcescens at a medical center in middle Taiwan
AU - Wu, Lii Tzu
AU - Tsou, Mei Fen
AU - Wu, Hwa Jene
AU - Chen, Hui E.
AU - Chuang, Yin Ching
AU - Yu, Wen-Liang
PY - 2004/6
Y1 - 2004/6
N2 - Thirty-four clinical isolates of Serratia marcescens nonsusceptible to cefotaxime were collected from a medical center in middle Taiwan. Confirmatory tests for extended-spectrum β-lactamases (ESBLs) by cefotaxime and ceftazidime ± clavulanic acid using Etest ESBL Screen identified only one ESBL producer; the remaining 33 isolates revealed nondeterminable results, because of off-scale minimum inhibitory concentration (MIC) levels for cefotaxime ± clavulanic acid. Agar microdilution method using broader MIC ranges confirmed 21 ESBL-producers and one non-determinable result, achieving a highly predicting value compared to golden standard by PCR and DNA sequencing analysis, which identified 22 (65%) isolates containing bla CTX-M-3 genes. Only one strain carried concurrent CTX-M-3 and SHV-5 conferring high-level MICs to both cefotaxime (128 μg/mL) and ceftazidime (64 μg/mL). Other enzymatic mechanisms, such as chromosome-encoded AmpC including a novel SRT-2 enzyme, may confer resistance to cefotaxime on the remaining 12 isolates without ESBL bla genes. Thus, it is unreliable to predict the resistance mechanism by antibiogram, and current Etest ESBL Screen tests. Our study highlights expanding efforts to detect ESBLs in S. marcescens are urgently needed in Taiwan.
AB - Thirty-four clinical isolates of Serratia marcescens nonsusceptible to cefotaxime were collected from a medical center in middle Taiwan. Confirmatory tests for extended-spectrum β-lactamases (ESBLs) by cefotaxime and ceftazidime ± clavulanic acid using Etest ESBL Screen identified only one ESBL producer; the remaining 33 isolates revealed nondeterminable results, because of off-scale minimum inhibitory concentration (MIC) levels for cefotaxime ± clavulanic acid. Agar microdilution method using broader MIC ranges confirmed 21 ESBL-producers and one non-determinable result, achieving a highly predicting value compared to golden standard by PCR and DNA sequencing analysis, which identified 22 (65%) isolates containing bla CTX-M-3 genes. Only one strain carried concurrent CTX-M-3 and SHV-5 conferring high-level MICs to both cefotaxime (128 μg/mL) and ceftazidime (64 μg/mL). Other enzymatic mechanisms, such as chromosome-encoded AmpC including a novel SRT-2 enzyme, may confer resistance to cefotaxime on the remaining 12 isolates without ESBL bla genes. Thus, it is unreliable to predict the resistance mechanism by antibiogram, and current Etest ESBL Screen tests. Our study highlights expanding efforts to detect ESBLs in S. marcescens are urgently needed in Taiwan.
UR - http://www.scopus.com/inward/record.url?scp=2942536009&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=2942536009&partnerID=8YFLogxK
U2 - 10.1016/j.diagmicrobio.2004.02.004
DO - 10.1016/j.diagmicrobio.2004.02.004
M3 - Article
C2 - 15183862
AN - SCOPUS:2942536009
VL - 49
SP - 125
EP - 129
JO - Diagnostic Microbiology and Infectious Disease
JF - Diagnostic Microbiology and Infectious Disease
SN - 0732-8893
IS - 2
ER -