Distribution of β-Lactamase Genes and Genetic Context of bla_KPC-2 in Clinical Carbapenemase-Producing Klebsiella pneumoniae Isolates

Figures & data

Figure 1 Dendrogram of XbaI-digested genomic DNA of 40 KPC-Kp isolates. Five different clusters were identified based on 85% similarity of PFGE profiles. An asterisk (*) indicates that the bla_KPC-2 plasmid in the strain was transferable by conjugation.

Table 1 Antimicrobial Susceptibility Testing Results of Carbapenemase-Producing Klebsiella pneumoniae Isolates from 2015 to 2017 (mg/L)

Antibiotics	Range	MIC50	MIC90	MIC Interpretation
				S (%)	I (%)	R (%)
Ceftazidime^a	16–256	64	256	0	0	100
Ceftazidime/avibactam^b	0.5–16	2	2	97.5	0	2.5
Cefotaxime^a	8–512	256	512	0	0	100
Cefepime^a	16–256	256	>256	0	0	100
Aztreonam^a	128–1,024	1,024	>1,024	0	0	100
Imipenem^a	8–512	32	64	0	0	100
Meropenem^a	4–1,024	32	64	0	0	100
Ertapenem^a	32–1,024	512	512	0	0	100
Gentamicin^a	0.25–1,024	128	512	37.5	0	62.5
Tobramycin^a	0.25–1,024	128	512	37.5	5	57.5
Amikacin^a	0.125–1,024	1,024	>1,024	42.5	0	57.5
Ciprofloxacin^a	16–256	32	128	0	0	100
Levofloxacin^a	8–128	32	64	0	0	100
Fosfomycin^a	32–1,024	512	1,024	5	10	85
Chloramphenicol^a	2–512	512	512	20	2.5	77.5
Tigecycline^b	0.5–32	2	8	80	12.5	7.5
Colistin^b	0.25–2	1	1	100	0	0

Notes: ^aThe antimicrobial susceptibility test of these antibiotics was conducted by the agar diffusion method and interpreted by CLSI criteria; ^bFor colistin, tigecycline and ceftazidime/avibactam, the antimicrobial susceptibility test was performed using broth microdilution method and interpreted by EUCAST criteria.

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

Table 2 Resistance Genes and Carbapenem MIC Levels (mg/L) of Wild Strains and Transconjugants

Strains	β-Lactam Genes	ETA	MEM	IPM	Replicon Types	ST Types
KP1878	blaKPC-2, blaTEM-1, blaCTX-M-65, blaSHV-11	512	256	64	IncFII	11
pKPC1878/EC600	blaKPC-2, blaTEM-1, blaCTX-M-65	16	8	4	IncFII	-
KP1880	blaKPC-2, blaTEM-1, blaCTX-M-65, blaSHV-11	256	128	32	IncFII, IncFIIK	11
pKPC1880/EC600	blaKPC-2, blaTEM-1, blaCTX-M-65	4	2	2	IncFII	-
KP2159	blaKPC-2, blaTEM-1, blaCTX-M-6, blaSHV-2	32	8	8	IncFIA, IncFIIK	656
pKPC2159/EC600	blaKPC-2, blaTEM-1	8	2	2	IncFIIK	-
KP3020	blaKPC-2, blaTEM-1, blaCTX-M-65, blaSHV-28	64	64	32	IncFIIK	15
pKPC3020-124/EC600	blaKPC-2, blaTEM-1	8	2	2	IncFIIK	-
KP4603	blaKPC-2, blaTEM-1, blaCTX-M-65, blaSHV-11, blaSHV-12	512	256	64	IncFII, IncFIIK	11
pKPC4603/EC600	blaKPC-2, blaCTX-M-65, blaSHV-12	16	4	4	IncFIIK	-
EC600	-	0.0075	0.03	0.015	-	-

Abbreviations: ETA, ertapenem; MEM, meropenem; IPM, imipenem.

Figure 2 Circular map of the plasmid pKPC3020-124 and comparative genomics analysis with its humongous plasmids. Counting from the center toward outside: (1) the scale in bp. (2) GC skew (G-C/G+C), with a positive GC skew toward the outside and a negative GC skew toward the inside. (3) GC content, with an average of 50%, whereby a G+C content of more than 50% is shown toward the outside, otherwise, inward. (4) Functional regions of multidrug resistance, conjugation, maintenance and unknown function. (5) Genes encoded in the leading strand (outwards) or the lagging strand (inwards). The plasmid pKPC3020-124 (CP061355) was used as the reference sequence and was compared to the sequences of (6) pBK34397 (KU295132.1), (7) p628-KPC (KP987218.1), (8) pKPHS2 (CP003224.1) and (9) pS1-KPC2 (MN615880.1). Genes with different functions are shown in different colors: red, antibiotic resistance; blue, mobile genetic elements; orange, transfer conjugation; light green, plasmid stability and replication; brown, heavy metal resistance; pink, toxin-antitoxin system; yellow, DNA metabolism; and gray, hypothetical proteins/genes with unknown functions.

Figure 3 Comparison of the bla_KPC-2-encoding regions between 10 representative plasmid sequences. The arrows represent the direction of transcription. ORFs are depicted by arrows and are colored based on predicted gene function. Light blue shading denotes homology of regions in each adjacent plasmid. The bla_KPC-2 genes are shown in red.