High Prevalence of 16S rRNA Methyltransferase Genes in Carbapenem-Resistant Klebsiella pneumoniae Clinical Isolates Associated with Bloodstream Infections in 11 Chinese Teaching Hospitals

Figures & data

Table 1 Antibiotic Resistance Gene Profiles in 16S RMTases-Positive and -Negative Strains

CRKPs	Carbapenem Resistance Genes, n (%)					ESBL Genes, n (%)
	blaNDM	blaKPC	blaIMP	blaNDM+blaKPC	blaIMP+blaKPC	blaCTX-M	blaSHV	blaCTX-M+blaSHV
16S+(n=78)	1 (1.3)	69 (88.5)	0	7 (8.9)	1 (1.3)	38 (48.7)	5 (6.4)	31 (39.7)
16S-(n=59)	24 (40.7)	31 (52.5)	2 (3.4)	2 (3.4)	0	24 (40.7)	4 (6.8)	16 (27.1)
P-values	0.00	0.00	0.184	0.299	1.00	0.349	1.00	0.123

Notes: 16S+: Represents the 16S RMTases-positive CRKP strains. 16S-: Represents the 16S RMTases-negative CRKP strains. +: Represents one CRKP strain harboring two antibiotic resistance genes simultaneously. P <0.05 was considered statistically significant.

Table 2 The Antimicrobial Resistance Profiling of 16S RMTases-Positive and -Negative Strains

Antimicrobials	CRKPs (n=137)				P-values	Breakpoints (µg/mL)
	16s+ (n=78)	%	16s- (n=59)	%		S	I	R
Imipenem	78	100.0	56	94.9	0.078	≤1	2	≥4
Meropenem	78	100.0	59	100	–	≤1	2	≥4
Cefoxitin	78	100.0	57	96.6	0.184	≤8	16	≥32
Cefotaxime	78	100.0	59	100	–	≤1	2	≥4
Cefepime	78	100.0	58	98.3	0.431	≤2	–	≥16
Ceftazidime	78	100.0	58	98.3	0.431	≤4	8	≥16
Aztreonam	78	100.0	49	83.1	0.000	≤4	8	≥16
Gentamicin	78	100.0	16	27.1	0.000	≤4	8	≥16
Amikacin	78	100.0	0	0	0.000	≤16	32	≥64
Ceftazidime/avibactam	9	11.5	27	45.8	0.000	≤8/4	–	≥16/4
Polymyxin B	5	6.4	1	1.7	0.236	–	≤2	≥4
Tigecycline	2	2.6	6	10.2	0.075	≤1	–	≥2
Piperacillin/tazobactam	77	98.7	56	94.9	0.315	≤16/4	32/464/4	≥128/4
Ciprofloxacin	74	94.9	39	66.1	0.000	≤0.06	0.12–0.5	≥1
Tetracycline	34	43.6	36	61	0.016	≤4	8	≥16
Minocycline	25	32.1	29	49.2	0.043	≤4	8	≥16
Sulfamethoxazole	38	48.7	39	66.1	0.042	≤2/38	–	≥4/76

Notes: 16S+: Represents the 16S RMTases-positive CRKP strains. 16S-: Represents the 16S RMTases-negative CRKP strains. P <0.05 was considered statistically significant.

Abbreviations: S, susceptible; I, intermediate; R, resistant.

Figure 1 PFGE results for 78 CRKP isolates harboring 16S rRNA methyltransferase genes. The adjacent information shown on the right represents number of strains, gender, age, ST type, ward, armA and rmtB presence, and cluster, respectively.

Abbreviations: PFGE, pulsed-field gel electrophoresis; CRKP, carbapenem-resistant Klebsiella pneumoniae.

Table 3 Characteristics of Different Clonotypes in 16S RMTases-Positive Strains

Clonotypes (n=78)	16S rRNA methyltransferase genes			Distribution Areas
	armA	rmtB	armA+rmtB
ST11-PFGE-A-KL64-wzi64 (n=3)	1	1	1	SH (n=2), JX (n=1)
ST11-PFGE-A-KL47-wzi209 (n=2)	0	2	0	FJ (n=1), HN (n=1)
ST11-PFGE-B-KL64-wzi64 (n=49)	1	48	0	JX (n=18), SD (n=10), HB (n=7), SH (n=6), HN (n=4), ZJ (n=2), FJ (n=2)
ST11-PFGE-B-KL47-wzi209 (n=12)	0	10	2	HN* (n=3), JX (n=3), HN (n=2), HB (n=2), SH (n=1), ZJ (n=1)
ST11-PFGE-B-KL27-wzi27 (n=1)	0	1	0	ZJ (n=1)
ST11-PFGE-C-KL64-wzi64 (n=3)	0	3	0	SH (n=2), HN (n=1)
ST11-PFGE-D-KL47-wzi209 (n=2)	0	2	0	FJ (n=2)
ST15-PFGE-F-KL19-wzi19 (n=2)	0	2	0	ZJ (n=2)
ST45-PFGE-G-KL24-wzi101 (n=1)	0	1	0	SD (n=1)
ST395-PFGE-E-KL3-wzi59 (n=1)	1	0	0	HN (n=1)
ST2237-PFGE-F-KL19-wzi19 (n=2)	2	0	0	SH (n=1), HN (n=1)

Note: ⁺Represents one CRKP strain harboring two antibiotic resistance genes simultaneously.

Abbreviations: SH, Shanghai; JX, Jiangxi; FJ, Fujiang; HN, Henan; SD, Shandong; HB, Hubei; ZJ, Zhejiang; HN*, Hunan.