Figure 1. Microscopy and colonial morphology of A. viridans

Microscopy and close up after growth in C0₂ in 48 h. Plate photos after growth in 24h (1) and 48h (2) (bioMerieux Columbia 5% sheep blood agar; gram stain: Huckert's formula (safranin counterstain); Gram-photos are 1000x). Photos from and with permission from Marie Delsarte and Alain Le Coustumier, Cohors, France.

Figure 2. Microscopy and colonial morphology of A. urinae

Microscopy and close up after growth in C0₂ in 48 h. Plate photos after growth in 24h (1) and 48h (2) and 72h (3) (bioMerieux Columbia 5% sheep blood agar; gram stain: Huckert's formula (safranin counterstain); Gram-photos are 1000x). Photos from and with permission from Marie Delsarte and Alain Le Coustumier, Cohors, France.

Figure 3. Microscopy and colonial morphology of A. sanguinicola

Figure 4. Time-kill curves of two. A. urinae blood-culture isolates (B1 and B8) (average of two or three experiments).

(a) Isolate B1, penicillin + gentamicin; (b) isolate B8, penicillin + gentamicin; (c) isolate B1, vancomycin + gentamicin; (d) isolate B8, vancomycin+ gentamicin. Error bars are standard deviation. A solid line marks the detection limit. Symbols for (a) and (b): ×, P2G10;▲, P10G10;▼, P2; ♦, P10; ●, G10; *, control. Symbols for (c) and (d): ×, V4 G10; ▲, V10 G10; ▼, V4; ♦, V10; ●, G10; *, control.

Table 1. Phenotypic characteristics of Aerococcus species and other catalase-negative, Gram-positive, non-chain forming cocci, which have been isolated from humans.

	Hemo-lysis	Vancomycin susceptibility	6.5% NaCl	Pyrrolidonyl aminopeptidase	Leucine aminopeptidase	Esculin hydrolysis	Acid production from:
							sucrose	trehalose	mannitol	maltose	lactose
A. urinae	α	S	+	-	+	-/(+)	+	-	+	-	-
A. sanguinicola	α	S	+	+	+	+	+	+	-	+	V
A. viridans	α	S	+	+	-	+	+	+	V	V	V
^aA. christensenii	α	S	+	-	+	-	-	-	-	-	-
^aA. urinaehominis	α	S	+	-	-	+	+	-	-	+	-

Dolosigranulum pigrum	n	S	+	+	+	+	-	-	-	-	-
Helcococcus kunzii	n	S	+	+	-	+	-	-	-	-	-
Pediococcus spp.	α	R	+	-	+	+	V
Gemella spp.	n/α	S	-	+	V	-	+
Alloiococcus otitidis^b	n	S	+	+	+	-	-

Abbreviations: Hemolysis = hemolytic reaction on agar containing 5% sheep or horse blood; n = no hemolysis, V = variable.

a: data based on examination of one strain each (Reference: 11)

b: Alloiococcus otitidis usually gives a weak positive reaction in the catalase test. Have been isolated from inner ear infections.

Table 2. Published data on minimal inhibitory concentrations (MICs) of antimicrobial agents for A. urinae and A. sanguinicola^a

Antibiotic (Breakpoints^b: S;R in μg/ml)	*A. urinae*			*A. sanguinicola*
	Range in μg/ml	MIC50/MIC90	No. of strains (Reference)	Range in μg/ml	MIC50/MIC90	No. of strains; (Reference)
Penicillin G (≤0.25; >2)	0.032-0.25 0.06	0.064/0.125 0.06/0.06	n = 56; (45) n = 10; (12)	0.03	0.03/0.03	n = 15; (22)
Amoxicillin (≤0.25; >2)	<0.032-0.25 0.08-0.32	0.064/0.125 0.23/0.32	n = 56;(45) n = 20; (5)	0.03 0.16-0.32	0.03/0.03 0.16/0.23	n = 15; (22) n = 8; (5)
Piperacillin (≤0.25; >2)	0.06-0.5	0.125/0.5	n = 56; (45)
Cefuroxim (≤0.5; >0.5)				0.25-1	0.5/1	n = 15; (22)
Cefotaxim (≤0.5; >0.5)				0.06-0.25	0.12/0.25	n = 15; (22)
Ceftriaxone (≤0.5; >0.5)	0.125-32	2/8	n = 56; (45)
Cefipime (≤0.5; >0.5)	0.032-8	0.25/1	n = 56; (45)
Meropenem (≤2; >2)				0.06-2	0.06/1.0	n = 15; (22)
Gentamicin -	4-512 1.5-48	64/128 4/32	n = 56; (45) n = 20; (5)	6-24	16/24	n = 8; (5)
Netilmicin -	4-256	32/64	n = 56; (45)
Amikacin -	16-1024	256/512	n = 56; (45)
Vancomycin -	0.5-1 0.25-0.5 0.75-1.5	0.5/1 0.5/0.5 1/1	n = 56; (45) n = 10; (12) n = 20; (5)	0.12-0.25 0.75-1	0.25/0.25 1/1	n = 15; (22) n = 8; (5)
Teicoplanin -	0.19-1	0.5/0.75	n = 20; (5)	0.19-0.75	0.38/0.5	n = 8; (5)
Rifampicin (≤0.06; >0.5)	<0.004-32	0.032/0.032	n = 56; (45)	2	2/2	n = 15; (22)
Erythromycin (≤0.25; >0.5)	0.125-2	0.5/1	n = 56; (45)	0.03-0.25	0.12/0.25	n = 15; (22)
Clindamycin (≤0.5; >0.5)				0.03-0.5	0.25/0.5	n = 15; (22)
Tetracycline	1-4	2/2	n = 56; (45)	2	2/2	n = 15; (22)
Ciprofloxacin -	0.125-4 0.094->32	1/2 0.5/>32	n = 56; (45) n = 20; (5)	1-4 0.19->32	1/4 0.75/>32	n = 15; (22) n = 8; (5)
Ofloxacin -	0.38->32	2/>32	n = 20; (5)	0.75->32	4/>32	n = 8; (5)
Levofloxacin (≤1; >2)				0.5-16	1/16	n = 15; (22)
Trimetoprim -	16->128	>128/>128	n = 56; (45)	0.25-4	1/2	n = 15; (22)
Co-trimoxazole (≤1; >2)	>32	>32/>32	n = 20; (5)	0.094-0.5	0.25/0.5	n = 8; (5)
Fosfomycin -	4-128	8/8	n = 20; (5)	48-128	64/128	n = 8; (5)
Chloramphenicol (≤8; >8)				2-4	2/4	n = 15; (22)
Quinopristin/ Dalfopristin -				1	1/1	n = 15; (22)
Linezolid (≤2; >4)				2	2/2	n = 15; (22)

a: Only data from publications examining >2 strains are given.

b: Breakpoints as recommended by The European Committee on Antimicrobial Susceptibility Testing (EUCAST). A – denotes that no breakpoints are given for non-hemolytic streptococci.

Table 3. Agar dilution MICs of 13 antimicrobial agents for A. urinae (n = 56) using 48 h of incubation in 5% CO₂ atmosphere. The upper limit for

susceptibility for non beta-hemolytic streptococci according to CLSI (marked in blue) or EUCAST (marked in yellow) are given. Antibiotics, for which

no upper limits have been defined are given in red.

Antimicrobial	MIC (mg/mL)
Agents	<0.008	0.008	0.016	0.032	0.064	0.125	0.25	0.5	1.0	2.0	4.0	8.0	16	32	64	128	256	512	>512
Benzylpenicilllin				17^a	24	13	2
Amoxycillin			6^b		23	19	3
Piperacillin					5	24	16	11
Ceftriaxone						2	3	8	10	18	7	2	3	1
Cefipime				1	3	8	23	7	9	3		1
Gentamicin											1	1	4	13	27	9	1
Netilmicin											2	4	7	29	13		1
Amikacin													1		1	4	29	20	1
Vancomycin								34	22	-
Rifampicin	6	1	14	29	4	1									1^c
Erythromycin						2	9	23	17	5
Ciprofloxacin						1	3	9	37	5	1
Oxytetracycline									20	35	1^d

CLSI: Clinical and Laboratory Standards Institute, Wayne, Pennsylvania, USA. EUCAST: European Committee on Antimicrobial Susceptibility Testing (see references)

^a No. of strains

^b MIC <0.032 mg/L

^c MIC >32 mg/L

^d MIC >2 mg/L