Genotype distribution of extended-spectrum and AmpC ?-lactamases produced by Escherichia coli and Klebsiella pneumoniae in 10 teaching hospitals of China
- VernacularTitle:全国10所教学医院产ESBLs和质粒AmpC酶大肠埃希菌及肺炎克雷伯菌的研究
- Author:
Hong-Li SUN
;
Yong-Zhong NING
;
Kang LIAO
;
Hui WANG
;
Ren-Yuan ZHU
;
- Publication Type:Journal Article
- Keywords:
Extended-spectrum?-lactamases;
Plasmid-mediated AmpC?-lactamases;
CTX-M-9;
DHA-1
- From:
Chinese Journal of Infection and Chemotherapy
2007;0(05):-
- CountryChina
- Language:Chinese
-
Abstract:
Objective To investigate the genotype distribution of extended-spectrum?-lactamases(ESBLs) and AmpC?-lacta- mases produced by Escherichia coli and Klebsiella pneumoniae in 10 teaching hospitals of China.Methods 90 clinical strains of E.coli and 61 strains of K.pneumoniae isolated in 2003 and confirmed to produce ESBLs were collected from 10 teaching hos- pitals in China.Analytical isoelectric focusing was used to measure the pI of the?-lactamases.Conjugation experiment was used to study the transfer of cefoxitin resistance.Plasmid-mediated AmpC enzyme genes were amplified and sequenced by multiplex polymerase chain reaction (MPCR).Results The prevalence of ESBL-producing E.coli and K.pneumoniae was about 50% in Wuhan,Nanjing and Jinan.The prevalence of ESBL-producing E.coli was lower than K.pneumoniae in Beijing.However,in other hospitals the prevalence of ESBL-producing E.coli was a little higher than K.pneumoniae.About 24.4% of ESBL-pro- ducing E.coli isolates and 19.4% of ESBL-producing K.pneumoniae isolates were resistant to cefoxitin.Cefoxitin-resistant i solate was identified in all hospitals except Shenyang.Major genotype of ESBL-producing isolates was CTX-M.The CTX-M-9 group was the most common group,followed by CTX-M-1.More K.pneumoniae isolates produced both ESBLs and AmpC en- zyme than E.coli.The genotype was CTX-M/DHA-1.The PCR results of 3 transconjugants producing both ESBLs and AmpC enzyme were the same as their donor isolates.Conclusions The genotype of ESBL-producing isolates is mainly CTX-M-9 group in these teaching hospitals.More K.pneumoniae isolates produced both ESBLs and AmpC enzyme than E.coli.Most of these isolates are due to geno type CTX-M/DHA-1,which can spread through plasmid.
