Clinical evaluation of Polymyxin NP test for screening polymyxin-resistant Enterobacteriaceae

doi:10.3969/j.issn.1673-8640.2020.10.007

Abstract

Abstract:

Objective To evaluate the clinical role of Polymyxin NP test for screening polymyxin-resistant Enterobacteriaceae. Methods A total of 461 isolates of Enterobacteriaceae were screened by Polymyxin NP test preliminarily. Broth microdilution method was performed to determine minimum inhibitory concentration（MIC） of polymyxin,and Kirby-Bauer method was used to determine the in vitro antimicrobial susceptibility of common antibiotics. Polymyxin-related genes,including pmrA,pmrB,phoP,phoQ,mgrB and mcr,were determined by polymerase chain reaction（PCR） and sequencing. Real-time quantitative polymerase chain reaction（qRT-PCR） was performed to determine the expression levels of genes associated with pmrA/pmrB,pmrD/pmrF and PhoP/PhoQ regulatory systems. Results Among the 461 Enterobacteriaceae isolates,within 2 h,13 polymyxin-resistant isolates were positive in Polymyxin NP test,and polymyxin-susceptible isolates were negative. Totally,10 of 13 polymyxin-resistant isolates belonging to Klebsiella pneumoniae resulted from insertion of mgrB as well as mutants and expression increasing of pmrA/pmrB and PhoP/PhoQ regulatory systems,and 1 isolate belonging to Escherichia coli was mediated bymcr-1 in plasmid. The resistance mechanisms of 2 isolates of Enterobacter cloacae were still unclear. There was no statistical significance between polymyxin-resistant and polymyxin-susceptible isolates（P>0.05）. Conclusions Polymyxin NP test is easy to perform and reliable. It could be used in screening polymyxin-resistant Enterobacteriaceae mediated by various mechanisms,which can provide a reference for treating infectious diseases and preventing the prevalence of resistance.

Key words: Enterobacteriaceae, Polymyxin NP test, Polymyxin resistance

CLC Number:

R446.5

TANG Yu, SHEN Pinghua, SHI Baoqing, JIANG Xiaofei. Clinical evaluation of Polymyxin NP test for screening polymyxin-resistant Enterobacteriaceae[J]. Laboratory Medicine, 2020, 35(10): 994-999.

Figures/Tables 6

References 18

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引物名称	引物序列（5'~3'）	产物大小/bp
mcr-1-F	CGGTCAGTCCGTTTGTTC	1 651
mcr-1-R	CCCACCGCCCATAATAC
mcr-2-F	ATGACATCACATCACTCTTGG	1 617
mcr-2-R	TTACTGGATAAATGCCGCGC
mcr-3-F	TTGGCACTGTATTTTGCATTT	542
mcr-3-R	TTAACGAAATTGGCTGGAACA
mcr-4-F	ATTGGGATAGTCGCCTTTTT	487
mcr-4-R	TTACAGCCAGAATCATTATCA

引物名称	引物序列（5'~3'）	产物大小/bp
mcr-1-F	CGGTCAGTCCGTTTGTTC	1 651
mcr-1-R	CCCACCGCCCATAATAC
mcr-2-F	ATGACATCACATCACTCTTGG	1 617
mcr-2-R	TTACTGGATAAATGCCGCGC
mcr-3-F	TTGGCACTGTATTTTGCATTT	542
mcr-3-R	TTAACGAAATTGGCTGGAACA
mcr-4-F	ATTGGGATAGTCGCCTTTTT	487
mcr-4-R	TTACAGCCAGAATCATTATCA

菌株	细菌种类	样本类型	Polymyxin NP 实验结果	多黏菌素耐药性	MIC/ （μg/mL）
菌株	细菌种类	样本类型	Polymyxin NP 实验结果	多黏菌素耐药性	多黏菌素E	多黏菌素B
ECL1207	阴沟肠杆菌	痰液	+	耐药	>32	>32
ECL1385	阴沟肠杆菌	痰液	+	耐药	32	32
ECO1500	大肠埃希菌	尿液	+	耐药	16	8
KP199	肺炎克雷伯菌	尿液	+	耐药	32	8
KP215	肺炎克雷伯菌	痰液	+	耐药	8	16
KP1036	肺炎克雷伯菌	血液	+	耐药	8	>32
KP1202	肺炎克雷伯菌	脑脊液	+	耐药	>32	>32
KP1292	肺炎克雷伯菌	痰液	+	耐药	>32	32
KP1324	肺炎克雷伯菌	尿液	+	耐药	16	8
KP340	肺炎克雷伯菌	尿液	+	耐药	16	8
KP1305	肺炎克雷伯菌	尿液	+	耐药	>32	32
KP1542	肺炎克雷伯菌	尿液	+	耐药	>32	>32
KP1543	肺炎克雷伯菌	尿液	+	耐药	>32	>32

菌株	细菌种类	样本类型	Polymyxin NP 实验结果	多黏菌素耐药性	MIC/ （μg/mL）
菌株	细菌种类	样本类型	Polymyxin NP 实验结果	多黏菌素耐药性	多黏菌素E	多黏菌素B
ECL1207	阴沟肠杆菌	痰液	+	耐药	>32	>32
ECL1385	阴沟肠杆菌	痰液	+	耐药	32	32
ECO1500	大肠埃希菌	尿液	+	耐药	16	8
KP199	肺炎克雷伯菌	尿液	+	耐药	32	8
KP215	肺炎克雷伯菌	痰液	+	耐药	8	16
KP1036	肺炎克雷伯菌	血液	+	耐药	8	>32
KP1202	肺炎克雷伯菌	脑脊液	+	耐药	>32	>32
KP1292	肺炎克雷伯菌	痰液	+	耐药	>32	32
KP1324	肺炎克雷伯菌	尿液	+	耐药	16	8
KP340	肺炎克雷伯菌	尿液	+	耐药	16	8
KP1305	肺炎克雷伯菌	尿液	+	耐药	>32	32
KP1542	肺炎克雷伯菌	尿液	+	耐药	>32	>32
KP1543	肺炎克雷伯菌	尿液	+	耐药	>32	>32

组别	株数	阿米卡星	庆大霉素	头孢唑啉	头孢呋辛	头孢噻肟	头孢美唑	头孢他啶
多黏菌素敏感组	448	223 （49.78）	293 （65.40）	354 （79.02）	348 （77.68）	346 （77.23）	250 （55.80）	299 （66.74）
多黏菌素耐药组	13	6 （46.15）	10 （76.92）	11 （84.62）	12 （92.31）	11 （84.62）	9 （69.23）	10（76.92）
合计	461	229（49.67）	303（65.73）	365 （79.18）	360 （78.09）	357（77.44）	259（56.18）	309（67.03）
组别	头孢吡肟	环丙沙星	哌拉西林	哌拉西林/他唑巴坦	复方磺胺甲噁唑	亚胺培南	美罗培南	替加环素^*
多黏菌素敏感组	325 （72.54）	351 （78.35）	391 （87.28）	252 （56.25）	249 （55.58）	238 （53.13）	240 （53.57）	31 （6.92）
多黏菌素耐药组	9 （69.23）	10 （76.92）	11 （84.62）	10 （76.92）	7 （53.85）	9 （69.23）	9 （69.23）	2 （15.38）
合计	334 （72.45）	361 （78.31）	402 （87.20）	262 （56.83）	256 （55.53）	247 （53.58）	249 （54.01）	33 （7.16）