TABLE 2.

Comparative yield of clinically important isolates in FN versus SN anaerobic blood culture bottles

Microorganism	No. of isolates detected by:			P value
	Both bottles	FN only	SN only
Gram-positive cocci
Staphylococcus aureus	113	173	12	<0.001
Coagulase-negative staphylococci	65	33	22	NSa
Streptococcus spp.b	14	2	5	NS
Enterococcus spp.c	51	16	9	NS
Gram-positive bacillid	1	1	0	NS
Gram-negative bacilli
Enterobacteriaceaee	65	37	11	<0.001
Other gram-negative bacillif	5	1	13	<0.005
Anaerobic bacteriag	5	9	3	NS
Yeastsh	0	1	19	<0.001
All microorganisms	319	273	94	<0.001

^aNS, not significant (P > 0.05).

^bIncludes eight viridans group Streptococcus, seven Streptococcus pneumoniae, two Streptococcus agalactiae and four Streptococcus pyogenes isolates.

^cIncludes 53 isolates of Enterococcus faecalis, 22 of Enterococcus faecium, and 1 of Enterococcus sp.

^dIncludes one Bacillus cereus and one Bacillus sp. isolate.

^eIncludes 34 Klebsiella pneumoniae, 29 Escherichia coli, 16 E. cloacae, 7 Salmonella sp., 6 Klebsiella oxytoca, 5 Enterobacter aerogenes, 5 Serratia marcescens, 3 Proteus mirabilis, 2 Citrobacter freundii, and 2 Serratia liquefaciens isolates and 1 isolate each of Enterobacter americana, Morganella morganii, Proteus rettgeri, and Providencia stuartii.

^fIncludes 15 isolates of P. aeruginosa and 1 isolate each of A. baumanii, Oligella sp., Haemophilus influenzae, and P. oryzihabitans.

^gIncludes four isolates of Bacteroides fragilis; four of Bacteroides thetaiotaomicron; three of Clostridium clostridioforme; two of the Bacteroides fragilis group; and one each of Bacteroides caccae, Bacteroides distasonis, Clostridium difficile, and Clostridium ramosum.

^hIncludes five of Candida albicans, five of C. parapsilosis, three of Candida tropicalis, three of Candida glabrata, two of Candida sp. and one each of Candida lusitaniae and Malassezia furfur.