TABLE 1.

Antibiotic MICs (for Y. pestis CO92), t_1/2 in serum, and doses (for Hsd:ND4 mice), calculated antibiotic time above MIC, peak antibiotic levels, and calculated antibiotic peak/MIC ratio

Antibiotic	MIC (μg/ml)a	t1/2 in serum (min)	Dose q6h (mg/kg)	Time above MIC (min)	Peak level (μg/ml)b	Peak level/MICc
Streptomycin	4	16.7	40	63	40.7–84.2	10.2–21.0
Netilmicin	<2	13.2	12	55	9.8–22.4	9.8–22.4
Gentamicin
Low dose	2	11.5	12	57	12–14.4	6–7.2
High dose		NDd	20	ND	45.5	22.7
Ciprofloxacin	<1	23.6	30	106	7.4–9.8	14.8–19.6
Ofloxacin	<2	20.7	30	58	8.5	8.5
Cefazolin	4	23.5	333	193	522–532	130.5–133
Cefotetan	<4	18.8	333	151	607	303.5
Ceftriaxone	<2	65	250	453	240–246	240–246
Ceftazidime	<1	41.9	333	351	120	240
Ceftizoxime	<2	15.2	333	148	625	625
Aztreonam	<1	34.1	333	305	156–398	312–796
Ampicillin	<1	13.8	333	123	165–239	330–478
Rifampin	<1	377	50	2,135	26.9	53.8

^aAfter 48 h of incubation. 

^bEach value represents either the mean of three to five separate specimens or the result obtained from three to five pooled specimens. 

^cWhen the MIC obtained was less than the lowest dilution used, the peak/MIC ratio was calculated based on the next lower dilution. 

^dND, not done.