Bacterial Endocarditis Caused by Abiotrophia defectiva in a Healthy Adult: A Case Report with Literature Review

형곤 제¹ 두열 송² 철훈 장^*1

¹ Departments of Thoracic Surgery Pusan National University Yangsan Hospital, Yangsan
² Laboratory Medicine,Pusan National University Yangsan Hospital, Yangsan

Abstract

Infective endocarditis caused by Abiotrophia defectiva is rarely encountered. A 67-year-old male transferred from a local hospital presented with severe dyspnea and pulmonary edema. Preoperative transthoracic echocardiography revealed severe mitral regurgitation with large vegetation. Blood cultures grew A. defectiva, a gram positive, nutritionally deficient streptococcus variant. Emergent mitral valve replacement through right thoracotomy was performed, and after completing six weeks of antibiotic combination therapy (vancomycin, ampicillin, and gentamicin), the patient recovered fully. Because of the need for prompt surgical treatment and long-term antibiotic therapy and lack of laboratory experience with the organism, physicians and laboratory workers should pay close attention to the possibility of A. defectiva infective endocarditis when gram positive cocci are detected in blood cultures. (Ann Clin Microbiol 2019;22:23-27)

Keywords

Abiotrophia defectiva Infective endocarditis Nutritionally variant streptococci

Acknowledgements

This work was supported by the annual clinical research grant from Pusan National University Yangsan Hospital.

Figures & Tables

Table 1. Summary of reported cases of Abiotrophia defectiva infective endocarditis

Pt. no.	Age (yr)	Sex	Pre-existing heart diseases	Other predisposing medical conditions	Identification methods of bacterium	Involved valves & surgery	Valve type	Antibiotics	Publication yr	References
1	67	M	No	No	MALDI-ToF/MS	MVR	Mechanical	VCM＋AMP＋GM		The current case
2	60	M	Hypertrophic obstructive cardiomyopathy, hypertension	No	ND	Mitral valve/no surgery	-	CRO＋GM	2018	9
3	31	M	No	Intravenous drug abuser	ND	MVR	Mechanical	AMP＋GM	2017	10
4	59	F	Ventricular septal defect	No	ND	PVR, AVR, MVP, TAP	Bioprosthesis	CRO＋AMP	2017	11
5	18	M	No	No	ND	AVR, MVR, Heart transplantation	Bioprosthesis	CRO＋VCM	2017	12
6	41	M	Ventricular septal defect	ND	ND	PVR, AVR, MVR	Bioprosthesis	PG＋GM	2017	13
7	26	F	No	Pregnancy(postpartum), fixed teeth brace	Vitek 2 Compact Analyzer	MVR	Mechanical	Broad spectrum antibiotics	2017	14
8	52	M	Mitral valve prolapse	Arterial hypertension	Polymerase chain reaction	MVR	Mechanical	AMP＋GM	2016	1
9	42	F	Rheumatic heart disease	No	ND	AVR, MVR	ND	AMP/SB＋GM	2016	15
10	65	M	Systolic/diastolic heart failure with intracardiac device (ICD)	No	MALDI-ToF/MS	Removal of ICD leads was impossible	-	PG＋CM	2016	16
11	50	M	Myxomatous mitral valve/mitral insufficiency	Tooth extraction	Vitek 2, 16S rRNA sequencing	MVR	Bioprosthesis	VAN＋GM	2016	17
12	25	F	Mitral valve prolapse/mitral insufficiency	Tooth extraction	Vitek 2, 16S rRNA sequencing	MVP	-	CRO＋RIF＋GM	2016	17
13	62	F	Rheumatic mitral stenosis/mitral valve regurgitation	Tooth extraction	MALDI-ToF/MS	MVR	Mechanical	VCM＋GM	2016	18
14	78	M	Mitral regurgitation/ischemic heart disease	COPD, hypertension, hypercholesterolemia	ND	Mitral valve/no surgery	-	PG＋GM	2016	19
15	39	F	No	Pregnancy (14th gestation week)	ND	MVR	Mechanical	AMP＋GM	2016	20
16	74	M	No	No	ND	AVR, MVR	Mechanical	AMP	2015	4
17	35	M	Ventricular septal defect	ND	Culture negative, metagenomic analysis	PVR, AVR, MVR	ND	AMP/SB＋GM	2015	21