Vancomycin-resistant enterococcal infection in a Thai university hospital: clinical characteristics, treatment outcomes, and synergistic effect

Figures & data

Table 1 Characteristics and outcomes of patients infected with vancomycin-resistant enterococci

Patient No.	Age (years)	CCI	SAPII	ICU	Mechanical ventilation	Type^a	VRE bacteremia	Poly-microbial	Days to definitive antibiotics	Definitive treatment	Duration of treatment (days)	Outcome	Appropriate treatment
1	61	3	25	No	No	LCBI	Yes	No	2	FOS, GEN	26	Survived	Yes
2	88	6	70	Yes	Yes	LCBI	Yes	No	3	LZD, GEN	6	Died	Yes
3^b,c	58	4	54	Yes	No	CLABSI	Yes	Yes	2	LZD, GEN	12	Died	Yes
4^b,c	45	2	62	Yes	Yes	LCBI	Yes	Yes	1	LZD, FOS	4	Died	Yes
5	71	7	56	Yes	No	IAB	Yes	No	2	FOS, GEN	9	Died	No
6^b,c	49	3	63	Yes	Yes	GIT	Yes	Yes	2	LZD	34	Died	Yes
7	55	6	44	No	Yes	Bone	No	Yes	11	TGC	30	Survived	Yes
8	86	7	52	No	No	UTI	No	No	6	LZD	10	Died	Yes
9^b	81	1	56	Yes	Yes	LCBI	Yes	No	7	LZD, FOS	4	Died	Yes
10^c	61	7	58	No	Yes	CLABSI	Yes	Yes	5	LZD	12	Died	Yes
11	51	9	29	No	No	IAB	Yes	No	4	LZD	14	Died	Yes
12^c	87	6	76	Yes	Yes	GIT	Yes	No	2	LZD	9	Died	Yes
13	78	2	60	No	Yes	GIT	No	Yes	3	LZD, FOS	7	Died	Yes
14	69	5	31	No	No	UTI	No	Yes	8	LZD	8	Died	Yes
15	80	5	24	No	No	UTI	No	No	5	FOS	9	Died	No
16	78	2	73	Yes	Yes	ST	No	Yes	4	LZD, GEN	23	Died	Yes
17	75	5	59	Yes	Yes	LCBI	Yes	No	2	LZD	14	Died	Yes
18^c	67	0	39	No	Yes	Bone	Yes	Yes	3	LZD, GEN then LZD	224	Survived	Yes
19^c	72	7	50	Yes	Yes	Bone	No	Yes	12	LZD	23	Survived	Yes
20	64	3	56	Yes	Yes	IAB	No	No	2	LZD	3	Died	Yes
21^c	54	2	26	No	No	Bone	No	Yes	0	TGC	30	Survived	Yes
22	68	7	35	No	No	Bone	No	No	24	LZD, FOS	4	Died	Yes
23	57	1	46	Yes	Yes	IAB	Yes	Yes	2	TGC	12	Died	Yes
24	84	3	46	Yes	Yes	IAB	No	Yes	7	LZD	18	Survived	Yes
25	86	6	71	Yes	Yes	ST	No	Yes	9	LZD, GEN	5	Died	Yes
26	55	0	16	No	No	Bone	No	Yes	12	LZD	38	Survived	Yes

Notes: ^aCDC/NHSN Surveillance Definitions for Specific Types of Infections; ^bNeutropenia; ^cPolymicrobial bacteremia.

Abbreviations: CCI, Charlson Co-morbidity Index; SAPII, Simplified Acute Physiology Score II; ICU, intensive care unit; LCBI, laboratory-confirmed bloodstream infection (primary bloodstream infection); CLABSI, central line-associated bloodstream infection; IAB, intra-abdominal infection; GIT, gastrointestinal tract infection; UTI, urinary tract infection; Bone, bone infection; ST, soft tissue infection; LZD, linezolid; FOS, fosfomycin; GEN, gentamicin; TGC, tigecycline.

Table 2 Type of infection and definitive treatment of patients infected with vancomycin-resistant enterococci

Characteristics	N (%)
Type of infection by site
● Gastrointestinal system infection	8 (30.8)
● Bloodstream infection	7 (26.9)
● Bone and joint infection	6 (23.1)
● Skin and soft tissue infection	2 (7.7)
● Urinary system infection	3 (11.5)
VRE bacteremia	13 (50)
Polymicrobial infection
● Candida spp.	7 (26.9)
● Enterobacteriaceae	6 (23.1)
● Pseudomonas aeruginosa	2 (7.7)
● Acinetobacter baumannii	2 (7.7)
Days to definitive antibiotics	3.5 (IQR 2-7)
Definitive monotherapy	15 (57.7)
● Linezolid	11 (42.3)
● Tigecycline	3 (11.5)
● Fosfomycin	1 (3.8)
Definitive combination therapy	11 (42.3)
● Linezolid-gentamicin	5 (19.2)
● Linezolid-fosfomycin	4 (15.4)
● Fosfomycin-gentamicin	2 (7.7)

Abbreviation: VRE, vancomycin-resistant enterococci.

Table 3 Molecular typing, antimicrobial minimum inhibitory concentrations, and antimicrobial combinations for 16 vancomycin-resistant enterococci strains

Patient NO.	RAPD group	MIC (µg/mL)							Susceptible^a		Fold reduction of antimicrobial MIC in combination with gentamicin										Synergistic activity
		VAN	LZD	TGC	FOS	AMP	CHL	GEN	CFX	LVX	LZD + GEN					FOS + GEN					TGC + FOS	LZD + FOS
		S≤4	S≤2	S≤0.25	S≤64	S≤8	S≤8	S≤500			GEN 0.25	GEN 0.5	GEN 1	GEN 2	GEN 4	GEN 0.25	GEN 0.5	GEN 1	GEN 2	GEN 4
1	A	128	1.5	0.094	128	64	32	≤500	R	R	N	>4	>4	>4	>4	4	4	4	4	4	ADD	ADD
2	C	128	1.5	0.094	192	>256	16	≤500	R	R	N	>4	>4	>4	>4	4	4	4	4	4	INDIF	ADD
3	A	>128	1.5	0.38	128	64	16	≤500	R	R	>4	>4	>4	>4	>4	N	N	N	N	N	ADD	ADD
4	A	>128	1	0.5	192	64	16	>500	S	R	N	N	N	N	N	N	N	N	N	N	SYN	SYN
5	B	64	1.5	0.125	192	64	16	≤500	S	R	N	N	>4	>4	>4	N	2	>4	>4	>4	INDIF	ADD
6	B	128	2	0.125	192	64	32	≤500	S	R	N	2	>4	>4	>4	N	N	2	2	2	ADD	ADD
7	A	>128	2	0.125	256	128	16	≤500	S	R	N	N	N	>4	>4	N	N	4	>4	>4	ADD	SYN
8	A	128	1	0.125	192	128	16	≤500	R	R	N	2	>4	>4	>4	2	4	4	4	4	ADD	ADD
9	C	64	2	0.125	128	32	8	>500	R	R	–	–	–	–	–	–	–	–	–	–	ADD	ADD
10	A	128	0.75	0.125	96	64	16	>500	R	R	–	–	–	–	–	–	–	–	–	–	ADD	SYN
11	A	128	1.5	0.38	128	64	32	>500	S	R	–	–	–	–	–	–	–	–	–	–	ADD	ADD
12	A	128	2	0.094	128	>256	32	>500	R	R	–	–	–	–	–	–	–	–	–	–	ADD	ADD
13	A	128	1.5	0.094	>1,024	64	2	≤500	R	R	N	N	N	2	>4	–	–	–	–	–	–	–
14	D	64	1.5	0.25	>1,024	8	8	≤500	R	R	>4	>4	>4	>4	>4	–	–	–	–	–	–	–
15	A	>128	1	0.094	>1,024	128	16	≤500	R	R	N	N	2	>4	>4	–	–	–	–	–	–	–
16	A	128	1.5	0.064	>1,024	128	16	≤500	R	R	N	N	N	>4	>4	–	–	–	–	–	–	–
MIC 50		128	1.5	0.125	192	64	16	≤500
MIC 90		>128	2	0.38	>1,024	128	32	>500

Notes: ^aInterpreted by disk diffusion test.

Abbreviations: MIC, minimum inhibitory concentration; VAN, vancomycin; LZD, linezolid; TGC, tigecycline; FOS, fosfomycin; AMP, ampicillin; CHL, chloramphenicol; GEN, gentamicin; CFX, ciprofloxacin; LVX, levofloxacin; SYN, synergy; ADD, additive; INDIF, indifferent; N, no change.