Report of a Fatal Purulent Pericarditis Case Caused by ST11-K64 Carbapenem-Resistant Hypervirulent Klebsiella pneumoniae

Figures & data

Figure 1 A 2D (top) and M-mode (bottom) imaging of parasternal long-axis echocardiogram showing pericardial tamponade. Bright yellow arrows show dark echo-free signal from pericardial fluid with left ventricular contraction in both end-diastolic and end-systolic.

Abbreviations: RV, right ventricle; LV, left ventricle; LA, left atrium.

Table 1 Results of Antimicrobial Susceptibility Testing (Broth Microdilution)

Antibiotic	MIC (µg/mL)	Susceptibility
Cefotaxime	>32	R
Cefoxitin	>16	R
Cefazolin	>16	R
Ciprofloxacin	>2	R
Cefepime	>16	R
Cefuroxime	>16	R
Gentamicin	>8	R
Ertapenem	>4	R
Imipenem	>8	R
Meropenem	>8	R
Levofloxacin	>4	R
Piperacillin/tazobactam	>64	R
Tigecycline	≤2	S
Polymyxin B	1	S

Notes: Interpretative results are reported according to CLSI document M100 (Performance Standards for Antimicrobial Susceptibility Testing, 31st Edition 2021).

Abbreviations: MIC, minimum inhibitory concentration of the antibiotic; R, resistant, S, sensitive.

Figure 2 Representative image string test. Strings >5mm indicates the hypermucoviscous phenotype of the KP strain.

Table 2 Potential Resistance Genes from Pericardial Effusion Isolate, Predicted by CARD Annotation

Antibiotic Resistance Mechanism		Gene	Identity (%)	Result
Antibiotic efflux	ABC antibiotic efflux pump	msbA	80.62	+
	RND antibiotic efflux pump	acrA	97.74	+
		acrB	83.81	+
		mdtB	81.28	+
		mdtC	81.64	+
		baeR	81.63	+
		marA	81.57	+
		acrD	80.17	+
		mdtA	78.41	+
		mdtH	76.21	+
		mdtK	75.99	+
	MFS antibiotic efflux pump	tet(A)	100.00	+
		kpnG	99.49	+
		kpnE	99.45	+
		kpnH	84.16	+
		emrR	83.14	+
		mdfA	77.35	+
Antibiotic inactivation	CTX-M beta-lactamse	blaCTX-M-65	100.00	+
	KPC beta-lactamse	blakpc-1	100.00	+
	Ambler class A beta-lactamse	LAP-2	100.00	+
	TEM beta-lactamse	blaTEM-1	99.88	+
	Chloramphenicol acetyltransferase (CAT)	cat II	96.11	+
	Fosfomycin thiol transferase	fosA6	99.45	+
Antibiotic target replacement	Sulfonamide resistance	sul2	100.00	+
Reduced permeability to antibiotic	Porin with reduced permeability to beta-lactams	ompK37	95.24	+
Antibiotic target alteration	16S rRNA methyltransferase	rmtB	100	+
	Phosphoethanolamine transferase	pmrF	77.26	+

Notes: +: Genes aligned with identity >75% were considered positive.

Table 3 Potential Virulence-Associated Genes from Pericardial Effusion Isolate, Predicted by VFDB Annotation

Virulence Mechanism		Gene	Identity (%)	Result
Iron uptake system	Yersiniabactin	ybtU	100.00	+
		ybtQ	99.94	+
		ybtE	99.94	+
		ybtX	99.92	+
		ybtA	99.90	+
		fyuA	99.90	+
		ybtS	99.85	+
		ybtP	99.83	+
		irp1	99.88	+
		irp2	99.79	+
		ybtT	99.25	+
	Aerobactin	iucB	93.14	+
		iucC	90.63	+
		iutA	89.32	+
		iucA	88.75	+
		iucD	77.38	+
	Enterobactin	entB	82.31	+
		fepC	80.83	+
		entA	80.40	+
		fepG	79.61	+
		fepA	77.94	+
		entS	77.90	+
		fepB	77.11	+
		entE	76.94	+
		fepD	75.59	+
Fimbriae	Type 1 fimbriae	fimE	75.70	+
		fimA	75.14	+
Pilus structure	Escherichia coli common pilus structural subunit	yagZ/ecpA	89.90	+
	Escherichia coli common pilus chaperone	yagY/ecpB	86.40	+
		yagV/ecpE	84.39	+
	Escherichia coli common pilus usher	yagX/ecpC	87.61	+

Notes: +: Genes aligned with identity >75% were considered positive.

Figure 3 Serum survival assay of three isolates (pericardial, blood and ascites). (A) Colony-forming units (CFUs) recovery after co-incubation of the isolates with pooled normal serum on blood plates for 1, 2 and 3 hours. Images are representative of two parallel samples of each isolate. (B) Mean viable CFU counts of the replicates at each time point.