TABLE 2.

Microbial species involved in the infected cases^a

Microbial species	All sites (n = 176)b	Hip (n = 99)	Knee (n = 64)	Shoulder (n = 13)
Staphylococcus species
S. aureus	58 (33)	33 (33.3)	22 (34.4)	3 (23.1)
S. epidermidis	39 (22.2)	22 (22.2)	14 (21.9)	3 (23.1)
S. lugdunensis	9 (5.1)	3 (3)	6 (9.4)	0
S. capitis	7 (4)	5 (5)	2 (3.1)	0
S. caprae	1 (0.6)	1 (1)	0	0
S. haemolyticus	1 (0.6)	0	1 (1.6)	0
S. hominis	1 (0.6)	1 (1)	0	0
S. xylosus	1 (0.6)	0	1 (1.6)	0
Staphylococcus sp.	0	0	0	0
Streptococcus species
S. agalactiae	8 (4.5)	3 (3)	4 (6.2)	1 (8)
S. bovis	1 (0.6)	0	1	0
S. dysgalactiae	1 (0.6)	1 (1)	0	0
S. oralis	2 (1.1)	0	2 (3.1)	0
S. pneumoniae	2 (1.1)	1	0	1 (8)
S. sanguinis	1 (0.6)	1 (1)	0	0
Propionibacterium species
P. acnes	13 (7.4)	6 (6.1)	2 (3.1)	5 (38.5)c
P. avidum	3 (1.7)	2 (2)	0	1 (8)
Other bacterial species
Acinetobacter ursingii	1 (0.6)	0	1 (1.6)	0
Anaerococcus hydrogenalis	1 (0.6)	0	1 (1.6)	0
Corynebacterium striatum	3 (1.7)	2 (2)	1 (1.6)	0
Enterobacter cloacae	8 (4.5)	6 (6.1)	2 (3.1)	0
Enterococcus faecalis	13 (7.4)	10 (10.1)	2 (3.1)	1 (8)
Enterococcus faecium	2 (1.1)	1 (1)	1 (1.6)	0
Escherichia coli	6 (3.4)	6 (6.1)	0	0
Finegoldia magna	4 (2.3)	2 (2)	1 (1.6)	1 (8)
Granulicatella adjacens	1 (0.6)	1 (1)	0	0
Klebsiella pneumoniae	2 (1.1)	2 (2)	0	0
Morganella morganii	1 (0.6)	1 (1)	0	0
Peptoniphilus harei	2 (1.1)	1 (1)	1 (1.6)	0
Pseudomonas aeruginosa	5 (2.8)	2 (2)	3 (4.7)	0
Salmonella sp.	2 (1.1)	2 (1)	0	0
Fungal species
Candida albicans	1 (0.6)	0	1 (1.6)	0

^aMicrobial species recovered from at least one intraoperative sample (virulent organisms) or from at least two intraoperative samples (nonvirulent organisms). Data are number (%) of cases; the percentage represents the proportion of all infected cases, culture-proven or not.

^bNine infections with sinus tracts were associated with negative (n = 7) or nonsignificant (n = 2) microbiological cultures.

^cP. acnes was found significantly more frequently in the shoulder than in the hip (P = 0.0001) or knee (P = 0.0002).