Table I.

Micro-organisms reported as causing surgical site infection (SSI) following hip or knee prosthesis surgery (Apr 2010 to Mar 2013)

		London		Midland and East of England		North of England		South of England		England (total)
No.	%	n	%	n	%	n	%	n	%	n	%
All SSI isolates	MSSA	25	20.2	88	27.2	87	26.9	91	29.2	291	26.9
	MRSA	3	2.4	24	7.4	8	2.5	10	3.2	45	4.2
	CoNS	39	31.5	73	22.5	85	26.3	79	25.3	276	25.5
	Enterobacteriaceae	20	16.1	52	16.0	58	18.0	39	12.5	169	15.6
	Other bacteria*	10	8.1	35	10.8	26	8.0	40	12.8	111	10.2
	Enterococcus spp.	11	8.9	20	6.2	31	9.6	17	5.4	79	7.3
	Streptococcus spp.	5	4.0	24	7.4	17	5.3	21	6.7	67	6.2
	Pseudomonas spp.	11	8.9	6	1.9	11	3.4	14	4.5	42	3.9
	Fungi	0	0.0	2	0.6	0	0.0	1	0.3	3	0.3
	Total	124	100	324	100	323	100	312	100	1,083	100
Deep or organ-space SSI isolates	CoNS*	23	31.5	51	24.6	71	30.5	64	27.2	209	27.9
	MSSA	18	24.7	50	24.2	62	26.6	54	23.0	184	24.6
	MRSA	1	1.4	13	6.3	3	1.3	8	3.4	25	3.3
	Enterobacteriaceae	12	16.4	34	16.4	40	17.2	35	14.9	121	16.2
	Other bacteria†	5	6.8	20	9.7	19	8.2	32	13.6	76	10.2
	Enterococcus spp.	5	6.8	18	8.7	18	7.7	13	5.5	54	7.2
	Streptococcus spp.	3	4.1	18	8.7	12	5.2	19	8.1	52	7.0
	Pseudomonas spp.	6	8.2	2	1.0	8	3.4	9	3.8	25	3.3
	Fungi	0	0.0	1	0.5	0	0.0	1	0.4	2	0.3
	Total	73	100	207	100	233	100	235	100	748	100

* The majority in this group comprised diptheroids/Corynebacterium spp. (40%) followed by unidentified organisms (31%) † The majority in this group comprised diptheroids/Corynebacterium spp. (42%) followed by unidentified organisms (28%) MSSA, met(h)icillin-sensitive S. aureus; MRSA, met(h)icillin-resistant S. aureus; CoNs,coagulase-negative staphylococci