Carbapenem-Resistant Klebsiella aerogenes Clinical Isolates from a Teaching Hospital in Southwestern China: Detailed Molecular Epidemiology, Resistance Determinants, Risk Factors and Clinical Outcomes
Authors Ma DY, Huang HY, Zou H, Wu ML, Lin QX, Liu B, Huang SF
Received 24 October 2019
Accepted for publication 13 January 2020
Published 19 February 2020 Volume 2020:13 Pages 577—585
Checked for plagiarism Yes
Review by Single anonymous peer review
Peer reviewer comments 2
Editor who approved publication: Dr Sahil Khanna
De-Yu Ma, 1,* Han-Yu Huang, 2,* Hua Zou, 1 Meng-Lu Wu, 1 Qiu-Xia Lin, 1 Bo Liu, 3 Shi-Feng Huang 1
1Department of Laboratory Medicine, The First Affiliated Hospital of Chongqing Medical University, Chongqing, People’s Republic of China; 2Department of Radiology, Chongqing Health Center for Women and Children, Chongqing, People’s Republic of China; 3Department of Burn and Plastic Surgery, The First Affiliated Hospital of Chongqing Medical University, Chongqing, People’s Republic of China
*These authors contributed equally to this work
Correspondence: Bo Liu
Department of Burn and Plastic Surgery, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China, No. 1 Friendship Road, Yuzhong District, Chongqing 400016, People’s Republic of China
Department of Clinical Laboratory, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China, No. 1 Friendship Road, Yuzhong District, Chongqing 400016, People’s Republic of China
Purpose: Little is known about the epidemiology and carbapenem-resistance determinants of carbapenem-resistant K. aerogenes (CRKA) isolated from a single medical center. The present study was initiated to characterize the molecular epidemiology and the carbapenem-resistance mechanisms of CRKA isolated during 2012– 2018 from a teaching hospital in southwest China, and to investigate the risk factors and clinical outcomes of CRKA infections as well.
Methods: Pulsed-field gel electrophoresis (PFGE) was employed for epidemiological analysis. PCR amplification and DNA sequencing were used to examine the antibiotic-resistance determinants. Plasmids were extracted and characterized by PCR-based replicon typing and conjugation assays. In order to further investigate the risk factors and clinical outcomes of CRKA infections, a retrospective case–control study was also performed.
Results: PFGE analysis showed 32 different PFGE patterns among the 36 non-duplicated CRKA strains collected. Most of the isolates harbored multi-drug resistance (MDR) genes, including 2 (5.6%) carrying blaNDM-1, 1 (2.8%) harboring blaKPC-2, 13 (36.1%) carrying ESBL genes, 23 (63.9%) carrying ampC genes, 34 (94.4%) carrying quinolone resistance determinants (QRD) genes and 9 (25%) carrying aminoglycoside resistance determinants (ARD) genes. The outer membrane porins, OmpE35 and OmpE36, were, respectively, lost in 4 and 2 isolates. The efflux pump inhibition experiments were positive in 25 (69.4%) of the CRKA strains. Multivariate analysis indicated that hypo-albuminaemia, invasive procedures, and carbapenem exposure were independent risk factors for acquiring CRKA infections.
Conclusion: No clonality relationship was identiﬁed among most of the 36 CRKA isolates. The over-expression of ESBLs and AmpC coupled with the efflux pumps contributed to carbapenem resistance in K. aerogenes. Additionally, this is the first report of CRKA isolate co-harboring blaNDM-1, blaCTX-M-15, blaEBC, blaACC, acc (6ʹ)-Ib, armA, qnrD and loss of OmpE36 in China. Hypo-albuminaemia, invasive procedures and carbapenem exposure were associated with acquisition of CRKA infections.
Keywords: case-control study, blaNDM-1, blaKPC-2, porins, efflux pumps
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