Mechanisms and molecular typing of carbapenem-resistant Proteus mirabilis strains deficient in swarming motility
10.3760/cma.j.issn.0254-5101.2016.10.003
- VernacularTitle:无迁徙生长碳青霉烯耐药奇异变形杆菌耐药机制及分子分型研究
- Author:
Long SUN
;
Xi LI
;
Xiaoting HUA
;
Keren SHI
;
Yanfei WANG
;
Ranfeng CHEN
;
Yunsong YU
- Publication Type:Journal Article
- Keywords:
Proteus mirabilis;
Swarming motility;
Carbapenemase;
Flagellum;
Nosocomial infection
- From:
Chinese Journal of Microbiology and Immunology
2016;36(10):734-739
- CountryChina
- Language:Chinese
-
Abstract:
Objective To investigate the mechanism and epidemiological characteristics of carbap-enem-resistant Proteus mirabilis ( PM) strains deficient in swarming motility. Methods PM strains were isolated from Hangzhou General Hospital of CAPF ( Chinese People′s Armed Police Forces) during January 2013 to December 2014. Bacterial motility and flagella of the PM strains were observed through semi-solid agar culture and flagella staining. Pulsed-field gel electrophoresis ( PFGE) was performed for homology anal-ysis. Antimicrobial susceptibility test and phenotypic confirmatory test were also carried out. PCR analysis and DNA sequencing were performed to confirm the genotype of resistant genes. Plasmid electroporation and S1-PFGE in combination with Southern blot hybridization were used to determine the location of the carbap-enem-resistant genes. Genetic structure of the blaKPC-2 gene was obtained by PCR mapping. Results A total of 42 PM isolates deficient in swarming motility were screened out and the resistance rates to imipenem and meropenem were 57. 1% and 52. 4%, respectively. PCR analysis and DNA sequencing confirmed that 24 carbapenem-resistant PM isolates deficient in swarming motility carried blaKPC-2 gene and belonged to three clones as indicated by the results of PFGE. Southern blot hybridization indicated that the blaKPC-2 gene was located on plasmids varying in size (26 kb, 55 kb and 139 kb). In addition, some of the strains harbored several resistant genes, such as blaTEM-1 , blaCTX-M-65 and rmtB. The genetic structures of strains carrying blaKPC-2 gene were ISKpn8, blaKPC-2 and ISKpn6-like from upstream to downstream. Conclusion Compared with the PM strains with swarming motility, the carbapenem-resistance rate was significantly higher in these PM strains deficient in swarming motility. Carbapenemases KPC-2 played an important role in the carbapen-em-resistant PM strains deficient in swarming motility. There was a cloning spread trend for carbapenem-re-sistant PM strains in our hospital. Clinicians should pay more attention to the risk of spreading.
