Over expression of AdeABC and AcrAB-TolC efflux systems confers tigecycline resistance in clinical isolates of Acinetobacter baumannii and Klebsiella pneumoniae
Rev. Soc. Bras. Med. Trop
; 49(2): 165-171, Mar.-Apr. 2016. tab, graf
Article
ي En
| LILACS
| ID: lil-782103
المكتبة المسؤولة:
BR1.1
ABSTRACT
Abstract INTRODUCTION:
Due to the wide use of tigecycline in the treatment of severe infections caused by multidrug-resistant (MDR) bacteria, clinical resistance to tigecycline has increased in recent years. Here, we investigated the relationship between tigecycline resistance and the expression of efflux pumps.METHODS:
Clinical isolates of Acinetobacter baumannii and Klebsiella pneumoniae were consecutively collected from hospitalized patients in three hospitals. The minimum inhibitory concentration (MIC) of tigecycline was determined using the broth microdilution method. Expression levels of efflux pump genes and regulators were examined by quantitative real-time reverse transcription polymerase chain reaction. The correlations between tigecycline MICs and gene expression levels were analyzed.RESULTS:
Overall, 1,026 A. baumannii and 725 K. pneumoniae strains were collected. Most strains were isolated from sputum. The tigecycline resistance rate was 13.4% in A. baumannii isolates and 6.5% in K. pneumoniae isolates. Overexpression of AdeABC and AcrAB-TolC efflux systems was observed found in clinical tigecycline-resistant isolates. The tigecycline MIC had a linear relationship with the adeB expression level in A. baumannii isolates, but not with the acrB expression level in K. pneumoniae isolates. There were significant linear trends in the overexpression of ramA as the tigecycline MIC increased in K. pneumoniae isolates.CONCLUSIONS:
Tigecycline resistance in A. baumannii and K. pneumoniae was strongly associated with the overexpression of efflux systems. More studies are needed to elucidate whether there are other regulators that affect the expression of adeB in A. baumannii and how ramA affects the expression of acrB in K. pneumoniae.Key words
النص الكامل:
1
الفهرس:
LILACS
الموضوع الرئيسي:
Drug Resistance, Bacterial
/
Acinetobacter baumannii
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Klebsiella pneumoniae
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Minocycline
/
Anti-Bacterial Agents
المحددات:
Humans
اللغة:
En
مجلة:
Rev. Soc. Bras. Med. Trop
موضوع المجلة:
MEDICINA TROPICAL
السنة:
2016
نوع:
Article