Table III.

Microbial etiologies of bloodstream infections (BSIs) in neutropenic patients who were not receiving antibacterials and in neutropenic patients who were receiving piperacillin-tazobactam or meropenem (breakthrough).

Causative organism(s)	BSIs in patients not receiving antibacterials1 (n = 101)	Breakthrough BSIs2 (n = 58)	P
Enterococcus faecium	0	33 (31 VRE)	<0.001
Klebsiella pneumoniae	20	4	0.03
Escherichia coli	16	1	0.006
Viridans group streptococci (VGS)	14	0	0.003
Pseudomonas aeruginosa	8	2	0.33
Staphylococcus aureus	7 (4 MRSA)	2 (both MRSA)	0.49
Coagulase-negative staphylococci (CoNS)	6	2	0.71
Moraxella catarrhalis	2	0	0.53
Acinetobacter baumannii	0	2	0.13
Stenotrophomonas maltophilia	0	2	0.13
Polymicrobial	20	5	0.06
Streptococci – Enterobacteriaceae	7	0	0.048
Multiple Enterobacteriaceae	5	1	0.42
Staphylococci – Enterobacteriaceae	3	0	0.30
Streptococci – Enterococcus faecalis (VSE)	2	0	0.53
Multiple VRE	0	1	0.37

MRSA, methicillin-resistant Staphylococcus aureus; VRE, vancomycin-resistant enterococci; VSE, vancomycin-susceptible enterococci.

¹Other etiologies of monomicrobial BSIs in patients not receiving antibacterials were Aeromonas hydrophila, Citrobacter freundii, Clostridium spp., Enterobacter aerogenes, Enterobacter cloacae, Fusobacterium varium, Klebsiella oxytoca and Rhodococcus spp. (n = 1, of each). Other etiologies of polymicrobial BSIs in patients who were not receiving antibacterials were VGS – anaerobic Gram-negative rod, Enterobacteriaceae – anaerobic Gram-negative rod, and S. aureus – VGS – Sphingomonas paucimobilis (n = 1, of each).

²Other etiologies of monomicrobial breakthrough BSIs were Acinetobacter lwoffii, Clostridium spp., Corynebacterium jeikeium, Enterococcus faecalis (VSE) and Klebsiella oxytoca (n = 1, of each). Other etiologies of polymicrobial breakthrough BSIs were multiple CoNS, CoNS – Stenotrophomonas maltophilia, and Corynebacterium spp. – Candida glabrata (n = 1, of each).