Giuseppe
Emeritus
[Source: Antimicrobial Agents and Chemotherapy, full page: (LINK). Abstract, edited.]
Molecular epidemiology and mechanisms of tigecycline resistance in clinical isolates ofAcinetobacter baumannii from a Chinese university hospital
Mei Deng 1, Man-Hua Zhu 1, Jun-Jie Li 1, Sheng Bi 1, Zi-Ke Sheng 2, Fei-Shu Hu 1, Jia-Jie Zhang 1, Wei Chen 1, Xiao-Wei Xue 1, Ji-Fang Sheng 1* and Lan-Juan Li 1
Author Affiliations: <SUP>1</SUP> State Key Laboratory for Diagnosis and Treatment of Infectious Disease, First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang 310003, People's Republic of China <SUP>2</SUP> Institute of Antibiotics, Huashan Hospital, Fudan University, Shanghai, People's Republic of China
ABSTRACT
For its remarkable ability to acquire antibiotic resistance and to survive in nosocomial environments, Acinetobacter baumannii has become a significant nosocomial infectious agent worldwide. Tigecycline is one of the few therapeutic options to treat infections caused by A. baumannii isolates. However, tigecycline resistance has been increasingly reported. Our aim was to assess the prevalence and characteristics of efflux-based tigecycline resistance in clinical isolates of A. baumannii collected from a hospital in China. A total of 74 A. baumannii isolates including 64 tigecycline non-susceptible A. baumannii (TNAB) and 10 tigecycline susceptible A. baumannii (TSAB) isolates were analyzed. The majority of them were detected to be positive for adeABC, adeRS, adeIJK and abeM, while the adeEgene was found in only one TSAB isolate. Compared with TSAB isolates, the mean expression level of adeB, adeJ, adeG and abeM in TNAB isolates were observed to increase by 29-, 3-, 0.7- and 1-fold, respectively. The efflux pump inhibitors (EPIs) PAβN and carbonyl cyanide 3-chlorophenylhydrazone (CCCP) could partially reverse the resistance pattern of tigecycline. Moreover, tetX1 gene was detected in 12 (18.8%) TNAB isolates. To our knowledge, this is the first report that tetX1gene was detected in the A. baumannii isolates. ST208 and ST191 which both clustered into clonal complex 92 (CC92) were the predominant sequence types (STs). This study showed that active efflux pump AdeABC appeared to play important roles in the tigecycline resistance of A. baumannii. The dissemination of TNAB isolates in our hospital is mainly attributable to the spread of CC92.
FOOTNOTES
*Corresponding author: Ji-Fang Sheng, Tel: +86 571 87236759 Fax: +86 571 87236755, E-mail: jifangsheng9200@163.com
Copyright ? 2013, American Society for Microbiology. All Rights Reserved.
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Molecular epidemiology and mechanisms of tigecycline resistance in clinical isolates ofAcinetobacter baumannii from a Chinese university hospital
Mei Deng 1, Man-Hua Zhu 1, Jun-Jie Li 1, Sheng Bi 1, Zi-Ke Sheng 2, Fei-Shu Hu 1, Jia-Jie Zhang 1, Wei Chen 1, Xiao-Wei Xue 1, Ji-Fang Sheng 1* and Lan-Juan Li 1
Author Affiliations: <SUP>1</SUP> State Key Laboratory for Diagnosis and Treatment of Infectious Disease, First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang 310003, People's Republic of China <SUP>2</SUP> Institute of Antibiotics, Huashan Hospital, Fudan University, Shanghai, People's Republic of China
ABSTRACT
For its remarkable ability to acquire antibiotic resistance and to survive in nosocomial environments, Acinetobacter baumannii has become a significant nosocomial infectious agent worldwide. Tigecycline is one of the few therapeutic options to treat infections caused by A. baumannii isolates. However, tigecycline resistance has been increasingly reported. Our aim was to assess the prevalence and characteristics of efflux-based tigecycline resistance in clinical isolates of A. baumannii collected from a hospital in China. A total of 74 A. baumannii isolates including 64 tigecycline non-susceptible A. baumannii (TNAB) and 10 tigecycline susceptible A. baumannii (TSAB) isolates were analyzed. The majority of them were detected to be positive for adeABC, adeRS, adeIJK and abeM, while the adeEgene was found in only one TSAB isolate. Compared with TSAB isolates, the mean expression level of adeB, adeJ, adeG and abeM in TNAB isolates were observed to increase by 29-, 3-, 0.7- and 1-fold, respectively. The efflux pump inhibitors (EPIs) PAβN and carbonyl cyanide 3-chlorophenylhydrazone (CCCP) could partially reverse the resistance pattern of tigecycline. Moreover, tetX1 gene was detected in 12 (18.8%) TNAB isolates. To our knowledge, this is the first report that tetX1gene was detected in the A. baumannii isolates. ST208 and ST191 which both clustered into clonal complex 92 (CC92) were the predominant sequence types (STs). This study showed that active efflux pump AdeABC appeared to play important roles in the tigecycline resistance of A. baumannii. The dissemination of TNAB isolates in our hospital is mainly attributable to the spread of CC92.
FOOTNOTES
*Corresponding author: Ji-Fang Sheng, Tel: +86 571 87236759 Fax: +86 571 87236755, E-mail: jifangsheng9200@163.com
Copyright ? 2013, American Society for Microbiology. All Rights Reserved.
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