Genotypes and virulence in serotype K2 Klebsiella pneumoniae from liver abscess and non-infectious carriers in Hong Kong, Singapore and Taiwan

Table 4 Virulence analysis for all 26 isolates by combining results obtained from presence of virulent associated genes, phagocytosis, serum complement killing and mice lethality

Strain no.	Source*	MLST	Phagocytosis	Serum	*kfu*	Aerobactin	LD₅₀(cfu)	Virulence^†
1	Carriage	ST65	S	S	-	-	1.2 × 10⁵	+
2	Liver	ST65	S	S	-	+	2.2 × 10⁶	-
3	Carriage	ST65	S	R	-	+	<1.9 × 10²	+++
4	Liver	ST65	S	R	-	+	<1.3 × 10²	+++
5	Liver	ST65	R	S	-	+	<1.1 × 10²	+++
6	Liver	ST65	R	R	-	+	<2.1 × 10²	+++
7	Liver	ST65	R	R	-	+	1.0 × 10²	+++
8	Carriage	ST65	R	R	-	+	<2 × 10²	+++
9	Liver	ST66	R	R	-	+	1.8 × 10²	+++
10	Liver	ST66	R	R	-	+	1.0 × 10³	+
11	Carriage	ST86	S	S	-	+	<3.7 × 10²	+++
12	Liver	ST86	R	S	-	+	3.4 × 10⁴	+
13	Liver	ST86	S	R	-	+	<1.0 × 10²	+++
14	Carriage	ST86	S	R	-	+	5.3 × 10⁴	+
15	Liver	ST86	R	R	-	+	5.5 × 10³	+
16	Liver	ST86	R	R	-	+	1.0 × 10²	+++
17	Liver	ST86	R	R	-	+	<1.0 × 10²	+++
18	Carriage	ST86	R	R	-	+	<1.0 × 10²	+++
19	Carriage	ST86	R	R	-	+	<1.0 × 10²	+++
20	Carriage	ST86	R	R	-	+	<1.0 × 10²	+++
21	Carriage	ST86	R	R	-	+	1.0 × 10³
22	Liver	ST373	R	R	-	+	<3.4 × 10²	+++
23	Carriage	ST374	R	S	+	+	1.5 × 10³	+
24	Carriage	ST375	R	R	+	+	2.8 × 10²	+++
25	Liver	ST380	R	R	+	+	<1.9 × 10²	+++
26	Liver	ST434	S	S	-	+	2.6 × 10⁴	+

*All isolates were carrying rmpA. No isolate was carrying all S. ^†Interpretation of virulence was referred to reference [2]. (+++) = hypervirulent strains with an LD50 of less than 1 × 10³ colony-forming units (CFU) are more likely to induce complications in mice. (+) = virulent strains with a 50% lethal dose (LD50) between ≥1 × 10³ and ≤1 × 10⁵ CFU are less likely to induce complications in mice. (−) = non-virulent strains with an LD50 of 1 × 10⁶ CFU of greater (do not cause complications).

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