Prevalence and molecular characteristics of colistin-resistant isolates among carbapenem-resistant Klebsiella pneumoniae in Central South China: a multicenter study

Jian, Zijuan; Liu, Yanjun; Wang, Zhiqian; Liu, Peilin; Wang, Jiahui; Yan, Qun; Liu, Wenen

doi:10.1186/s12941-024-00769-1

Annals of Clinical Microbiology and Antimicrobials

Table 2 Colistin MICs, chromosomal mutations in genes related to colistin resistance and relative expression levels of the pmrC and pmrK genes

From: Prevalence and molecular characteristics of colistin-resistant isolates among carbapenem-resistant Klebsiella pneumoniae in Central South China: a multicenter study

Strains	COL MIC (mg/L)	Chromosomal mutations related to colistin resistance^#					Relative expression level^*
Strains	COL MIC (mg/L)	mgrB	pmrA	pmrB	phoP	crrB	pmrC	pmrK
XY156	16	IS903B	WT	R256G T246A	WT	WT	1.28 ± 0.08	18.46 ± 1.43
XY158	32	WT	WT	R256G T246A T157P	WT	WT	5.63 ± 0.58	2.60 ± 0.21
XY160	16	WT	G53S	R256G T246A T157P	WT	WT	7.56 ± 0.78	1.93 ± 0.19
XY167	16	WT	WT	R256G T246A T157P	WT	WT	13.47 ± 0.88	2.35 ± 0.16
XY183	4	WT	A41T	T246A L213M T157P	E82K	C68S	14.67 ± 0.84	1.25 ± 0.20
XY185	16	WT	WT	R256G T246A T157P	WT	WT	31.19 ± 2.00	-^a
XY188	16	IS903B	WT	R256G T246A	WT	WT	1.58 ± 0.22	11.80 ± 1.01
XY190	16	IS903B	WT	R256G T246A	WT	I27V C68S	1.25 ± 0.07	15.08 ± 1.53
XY206	16	ISKpn74	WT	R256G T246A	WT	R248P^▲	-^a	4.87 ± 0.17
XY207	16	ISKpn74	WT	R256G T246A	WT	WT	-^a	5.38 ± 0.40
XY215	32	ISKpn26	G53S	R256G T246A	WT	WT	1.68 ± 0.09	6.72 ± 0.48
XY234	16	ISKpn26	WT	R256G T246A	WT	WT	-^a	10.86 ± 0.88
XY241	8	ISKpn26	WT	R256G T246A	WT	WT	-^a	5.44 ± 0.38
XY270	16	WT	WT	R256G T246A T157P	WT	WT	11.58 ± 0.85	1.82 ± 0.08
XY276	32	ISKpn26	WT	R256G T246A	WT	WT	1.89 ± 0.18	7.21 ± 0.52
XY284	8	ISKpn74	G53S	R256G T246A	WT	I27V C68S	1.30 ± 0.06	4.06 ± 0.30
XY295	8	WT	WT	R256G T246A T157P	WT	WT	8.18 ± 0.51	-^a
XY314	64	ISKpn26	WT	R256G T246A	WT	WT	1.10 ± 0.05	7.62 ± 0.79
XY318	32	WT	WT	R256G T246A T157P	WT	WT	10.81 ± 1.00	-^a
XY464	64	ISKpn14	WT	R256G T246A	WT	WT	-^a	5.42 ± 0.25
CZ21	8	WT	A41T	T246A L213M T157P	E82K	C68S	3.48 ± 0.21	2.58 ± 0.13
CZ26	8	WT	WT	R256G T246A T157P	WT	WT	14.33 ± 1.09	1.55 ± 0.16
HY4	64	ISKpn14	WT	R256G T246A	WT	WT	-^a	6.20 ± 0.28
LY21	8	WT	WT	R256G T246A T157P	WT	R248P^▲	8.73 ± 0.50	1.92 ± 0.29
YZ4	32	ISKpn14	WT	R256G T246A	WT	WT	-^a	7.00 ± 0.16
ZZ3	64	ISKpn26	WT	R256G T246A	WT	WT	-^a	4.91 ± 0.35

Abbreviations: COL: colistin; MIC, minimal inhibitory concentration; mg/L, milligram per liter; WT: wild-type
^# Colistin-susceptible K. pneumoniae MGH 78,578 (NC_009648.1) was used as reference for mutational analysis. The insertion mutations of mgrB and missense mutations of two-component regulatory system genes were listed in this table. The mutations predicted as deleterious by PROVEAN were in bold and the novel mutation was marked with ▲
^* Relative fold change of pmrC and pmrK genes in the ColR-CRKP isolates were detected by RT-qPCR compared with colistin-susceptible strain K. pneumoniae ATCC700603. Transcription levels were normalized to levels of rpsL gene. Values were represented by the mean ± standard deviation of three replicates using 2^−ΔΔCt method
^a Unaltered expression levels compared to K. pneumoniae ATCC700603

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ISSN: 1476-0711

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