Yumi Park1,2,3, Qute Choi1, Gye Cheol Kwon1, Sun Hoe Koo1. 1. Department of Laboratory Medicine, Chungnam National University Hospital, Daejeon, South Korea. 2. Department of Laboratory Medicine, Konyang University College of Medicine, Daejeon, South Korea. 3. Department of Laboratory Medicine, Konyang University Hospital, Daejeon, South Korea.
Abstract
BACKGROUND: The emergence and transmission of tigecycline- and carbapenem-resistant Klebsiella pneumoniae (TCRKP) have become a major concern to public health globally. Here, we investigated the molecular epidemiology and mechanisms of tigecycline resistance in carbapenem-resistant K pneumoniae (CRKP) isolates. METHODS: Forty-five non-duplicate CRKP isolates were collected from January 2017 to June 2019. We performed antimicrobial susceptibility tests, multilocus sequence typing (MLST), and pulsed-field gel electrophoresis (PFGE). PCR and DNA sequencing were performed for the detection and mutation analysis of acrR, oqxR, ramR, rpsJ, tet(A), and tet(X) genes, which are related to tigecycline resistance. The expression levels of efflux pump genes acrB and oqxB and their regulator genes rarA, ramA, soxS, and marA were assessed by quantitative real-time PCR. RESULTS: The resistance rate to tigecycline in CRKP isolates was 37.8% (17/45). K pneumoniae ST307 was a predominant clone type (70.6%, 12/17) among the TCRKP isolates. The expression levels of acrB (P < .001) and marA (P = .009) were significantly higher in the tigecycline-resistant group than in the tigecycline-intermediate and tigecycline-susceptible groups. Increased expression of acrB was associated with marA expression (r = 0.59, P = .013). CONCLUSIONS: We found that the activated MarA-induced overexpression of AcrAB efflux pump plays an important role in the emergence of tigecycline resistance in CRKP isolates.
BACKGROUND: The emergence and transmission of tigecycline- and carbapenem-resistant Klebsiella pneumoniae (TCRKP) have become a major concern to public health globally. Here, we investigated the molecular epidemiology and mechanisms of tigecycline resistance in carbapenem-resistant K pneumoniae (CRKP) isolates. METHODS: Forty-five non-duplicate CRKP isolates were collected from January 2017 to June 2019. We performed antimicrobial susceptibility tests, multilocus sequence typing (MLST), and pulsed-field gel electrophoresis (PFGE). PCR and DNA sequencing were performed for the detection and mutation analysis of acrR, oqxR, ramR, rpsJ, tet(A), and tet(X) genes, which are related to tigecycline resistance. The expression levels of efflux pump genes acrB and oqxB and their regulator genes rarA, ramA, soxS, and marA were assessed by quantitative real-time PCR. RESULTS: The resistance rate to tigecycline in CRKP isolates was 37.8% (17/45). K pneumoniae ST307 was a predominant clone type (70.6%, 12/17) among the TCRKP isolates. The expression levels of acrB (P < .001) and marA (P = .009) were significantly higher in the tigecycline-resistant group than in the tigecycline-intermediate and tigecycline-susceptible groups. Increased expression of acrB was associated with marA expression (r = 0.59, P = .013). CONCLUSIONS: We found that the activated MarA-induced overexpression of AcrAB efflux pump plays an important role in the emergence of tigecycline resistance in CRKP isolates.
Authors: Helio S Sader; Mariana Castanheira; Robert K Flamm; Rodrigo E Mendes; David J Farrell; Ronald N Jones Journal: Diagn Microbiol Infect Dis Date: 2015-06-23 Impact factor: 2.803
Authors: Paula Blanco; Sara Hernando-Amado; Jose Antonio Reales-Calderon; Fernando Corona; Felipe Lira; Manuel Alcalde-Rico; Alejandra Bernardini; Maria Blanca Sanchez; Jose Luis Martinez Journal: Microorganisms Date: 2016-02-16
Authors: Wenli Liao; Na Huang; Ying Zhang; Yao Sun; Tao Chen; Weiliang Zeng; Liqiong Chen; Hong Wen; Jianming Cao; Tieli Zhou Journal: Front Public Health Date: 2021-12-03