Table 1

Table 1. Antimicrobial Susceptibility Rates (%) for the Four Most Common Species of Gram-Negative Bacilli, 1994-2000

Table 2 Rates of Cross-Resistance (%) Among Selected Gram-Negative Bacilli, 1994-2000

	C. Pseudomonas aeruginosa Ciprofloxacin		D. Enterobacter species Ciprofloxacin		E. Klebsiella pneumoniae Ciprofloxacin
Antimicrobial	% resistant (n=1946)	% susceptible (n=6298)	% resistant (n=486)	% susceptible (n=4513)	% resistant (n=603)	% susceptible (n=4274)
Gentamicin	66.0	21.7	48.8	3.9	67.3	7.1
Ceftazidime	39.8	14.0	81.5	31.8	65.2	6.1
Imipenem	37.6	10.9	3.9	1.0	3.2	0.5
Amikacin	26.0	5.6	10.9	0.8	32.6	1.8

Note: numbers are percentages

Table 3. Association of Previously Administered Antibiotics with Multiresistant Enterobacter in the Initial Blood Culture

Multiresistant Enterobacter
Antibiotic*	Isolate n/N (%)	P Value
Any Antibiotic
Yes	36/103 (35%)
No	1/26 (4)	.002
Third-generation cephalosporin
Yes	22/32 (69)
No	14/71 (20)	.001

*Antibiotics received in the 2 weeks before the initial positive blood culture.

Data from Chow et al (7)

Table 4. Emergence of Resistance during Antibiotic Therapy for Enterobacter Bacteremia

Patient	Antibiotic Used	Emergence of Resistance to Drug	*MIC before Therapy (mg/mL)**	*MIC after Therapy (mg/mL)**	Duration of Therapy When Resistance Was Seen (days)	Source of Second Positive Culture	*Enterobacter* spp.	Outcome
1	Cefotaxime	Cefotaxime	<4	>32	16	Intraabdominal abscess	E. cloacae	Survived
2	Ceftazidime, tobramycin	Ceftazidime	<2	>16	18	Blood	E. cloacae	Survived
3	Ceftazidime	Ceftazidime	<2	>16	5	Blood	E. cloacae	Survived
4	Cefotaxime, amikacin	Cefotaxime	< 4	>32	6	Blood	E. aerogenes	Died
5	Ceftizoxime	Ceftizoxime	8	32	4	Blood	E. cloacae	Survived
6	Cefotaxime, gentamicin	Cefotaxime	8	32	7	Blood	E. aerogenes	Survived
7	Piperacillin, tobramycin	Tobramycin	<0.25	8	8	Two Central venous catheters	E. cloacae	Survived