Table 2.

Determination of bacterial load with quantitative 16S rRNA DNA PCR using original and V6 primers, compared conventional bacterial culture findings only when cultures demonstrated organisms.

Patient	Day	Bacterial culture	Original primer 16S copy number per ml CSF	V6 primer 16S copy number per mL CSF (if tested)
A. Coagulase-negative Staphylococcus only (n = 11). We had insufficient CSF to obtain PCR data for J and N on day 1, as well as B on day 1 and K on day 2.
A	1	S. epidermidis	477,000–835,000	n/a
B	5	S. epidermidis	253,000–328,500	227,500–235,500
C	1	Staphylococcus lugdunensis	194,000–280,500	n/a
	2	S. lugdunensis	188,500–281,000	n/a
E	1	Coagulase-negative Staphylococcus	211,850–247,150a and 384,200–453,950 and 344,050–358,200	n/a
	3	Coagulase-negative Staphylococcus	201,050–242,750a	n/a
F	1	Coagulase-negative Staphylococcus	3,627,000–3,600,050	n/a
G	1	S. epidermidis	52,500–70,000	n/a
I	1	S. epidermidis	26,850–90,500	n/a
	2	S. epidermidis	211,500–232,000	n/a
	3	S. epidermidis	173,000–244,500	n/a
	4	S. epidermidis	171,000–187,000	n/a
K	1	S. epidermidis	435,500–483,000	n/a
M (#2)	1	S. epidermidis	206,050–220,300	193,000–216,000
	2	S. epidermidis	129,100–164,050	150,500–171,000
	3	S. epidermidis	129,050–145,750	142,000–150,500
	4	S. epidermidis	106,500–147,250 and 133,000–197,850	103,500–117,500 and 156,500–177,500
B. Other single infecting organisms (n = 8). We had insufficient CSF to obtain PCR data for H (#2) on day 1 with S. aureus, as well as Ton day 3 with Serratia marcescens, Ron day 2 with E. faecalis and L on day 7 with Propionibacterium acnes.
D	1	S. aureus	153,500–165,000a	n/a
L	1	P. acnes	2,355,000–2,765,000	n/a
	2	P. acnes	168,500–225,000	n/a
M (#1)	1	Group A beta-hemolytic Streptococcus	406,400–565,000	445,500–610,000
O	1	P. acnes	77,000–100,500	66,500–73,250
P	1	E. coli	3,225,000–3,785,000	3,205,000–3,325,000
R	1	E. faecalis	256,500–314,500	306,500–324,000
T (#2)	1	S. marcescens	950,000–1,150,000	1,125,500–1,331,500
	2	S. marcescens	195,000–225,500	202,800–240,300
C. Infections with a several organisms (n = 6). We had insufficient CSF to obtain PCR data for S (#2) on day 1 with S. epidermidis, Staphylococcus warneri, and Diphtheroid bacilli, as well as for Q on day 1 with S. pneumoniae, S (#1) on day 17 and 18 with Micrococcus spp., and T (#1) on days 4 and 6 with S. aureus and day 11 with Staphylococcus hominis.
H (#1)	1	S. epidermidis and S. aureus	7,050,000–7,800,000	n/a
	3	S. aureus	96,500–145,000a and 85,500–100,500a and 78,500–114,500a	n/a
	4	S. aureus	21,550–164,000a and 4,670–27,550	n/a
	5	S. aureus	108,000–163,500a and 71,000–123,000a	n/a
	6	S. aureus	110,000–131,000a and 42,850–60,500	n/a
Q	3	No growth	3,140,000–3,775,000	3,440,000–4,080,000
	5	Staphylococcus capitis	940,000–1,165,000	1,020,000–1,525,000
S(#1)	1	Corynebacterium spp.	406,400–565,000	148,000–181,500
	10	Corynebacterium spp.	138,450–151,050	204,000–241,000
	11	Corynebacterium spp.	289,350–347,150	211,500–267,000
	12	Corynebacterium spp.	201,750–366,900	177,500–187,500
T (#1)	1	S. aureus	133,500–202,500	96,000–116,500
	2	S. aureus	234,500–256,500a	199,000–205,500
	3	S. aureus	175,000–219,500a	103,500–111,500
	5	S. aureus	226,500–293,500a	224,000–239,000a
	16	Coagulase-negative Staphylococcus	291,000–336,000	258,000–293,500
U	1	K. pneumoniae and Streptococcus mitis/oralis	318,350–383,650	349,650–471,950
	3	K. pneumoniae	137,850–159,900	151,400–177,300
	5	K. pneumoniae	177,050–192,950	181,850–265,100
	16	S. epidermidis and S. aureus	92,200–124,450	91,100–153,500

Subsequent days of infection treatment with negative CSF cultures are not provided here. Bolded primer counts are significantly different from negative CSF controls and later (culture-negative) samples drawn during the infection episode; these examples resemble the representative infection episodes shown in Figs. 3A and 3B.

^aAbove CSF negative controls, but not different from other samples drawn during the infection episode.