Table 1

Checkerboard study

*Various concentrations of ciprofloxacin and vancomycin were mixed in normal saline and balanced salt solution plus and incubated at 37°C. The medium was aliquot after 24 hours and 72 hours for antibiotics assay.
†No measurable loss.
A Initial concentrations (mg/l) of ciprofloxacin/vancomycin prepared in microtitre plate (amount in μg)
0/00/2500/1250/62.50/31.25
(0/0)(0/125)(0/62.5)(0/31.25)(0/15.625)
50/050/25050/12550/62.550/31.25
(25/0)(25/125)(25/62.5)(25/31.25)(25/15.625)
25/025/25025/12525/62.525/31.25
(12.5/0)(12.5/125)(12.5/62.5)(12.5/31.25)(12.5/15.625)
12.5/012.5/25012.5/12512.5/62.512.5/31.25
(6.25/0)(6.25/125)(6.25/62.5)(6.25/31.25)(6.25/15.625)
6.25/06.25/2506.25/1256.25/62.56.25/31.25
(3.125/0)(3.125/125)(3.125/62.5)(3.125/31.25)(3.125/15.625)
B Measurable concentrations (mg/l) of ciprofloxacin/vancomycin after 24 hours of incubation at 37°C in NS (calculated amount in μg)
0/00/3560/1890/1050/54
(0/0)(0/107)(0/57)(0/31)(0/16)
67/062/37664/18466/7868/56
(20/0)(19/113)(19/55)(20/23)(20/17)
36/033/37636/20933/9929/50
(11/0)(10/113)(11/63)(10/30)(9/15)
15/013/35213/17914/9214/46
(4/0)(4/105)(4/54)(4/28)(4/14)
7/08/5708/2617/1316/52
(2/0)(2/171)(2/78)(2/40)(2/16)
C Measurable concentrations (mg/l) of ciprofloxacin/vancomycin after 72 hours of incubation at 37°C in NS (calculated amount in μg)
0/00/12880/6370/2490/42
(0/0)(0/116)(0/57)(0/25)(0/17)
100/0174/1180100/345151/23857/50
(17/0)(17/118)(15/52)(18/29)(23/20)
29/062/84151/31192/30129/46
(12/0)(9/126)(8/47)(9/30)(12/18)
31/043/108667/82513/9015/43
(6/0)(5/130)(4/50)(5/36)(6/17)
5/05/3206/1606/916/39
(2/0)(2/128)(2/64)(2/37)(2/16)
D Percentage loss of antibiotics after 24 hours of incubation at 37°C in NS based on the amount calculated (ciprofloxacin/vancomycin in %)
0/00/150/90/0†0/0†
20/026/1023/1121/2518/0†
15/021/1017/0†21/4530/3
30/038/1638/1433/1138/12
33/025/0†22/0†30/0†45/0
E Percentage loss of antibiotics after 72 hours of incubation at 37°C in NS based on the amount calculated (ciprofloxacin/vancomycin in %)
0/00/80/80/200/0†
32/031/640/1728/98/0†
8/025/0†39/2526/47/0†
11/017/036/2115/0†7/0†
30/032/0†26/0†25/0†28/1
F Measurable concentrations (mg/l) of ciprofloxacin/vancomycin after 24 hours of incubation at 37°C in BSS Plus (calculated amount in μg)
0/00/2700/1380/630/33
(0/0)(0/122)(0/62)(0/28)(0/15)
51/052/27451/12043/6441/32
(23/0)(24/124)(23/54)(19/29)(19/15)
28/027/26428/14127/6528/34
(13/0)(12/119)(13/63)(12/29)(13/15)
13/013/26914/14713/6413/33
(6/0)(6/121)(6/66)(6/29)(6/15)
7/07/2547/1407/657/33
(3/0)(3/114)(3/63)(3/29)(3/15)
G Measurable concentrations (mg/l) of ciprofloxacin/vancomycin after 72 hours of incubation at 37°C in BSS Plus (calculated amount in μg)
0/00/2250/1350/620/35
(0/0)(0/101)(0/61)(0/28)(0/16)
14/017/24515/13713/6714/34
(6/0)(8/110)(7/62)(6/30)(6/15)
25/026/25724/13625/6322/33
(11/0)(12/116)(11/61)(11/29)(10/15)
14/013/27013/13713/6213/33
(6/0)(6/121)(6/62)(6/28)(6/15)
7/06/2567/1357/627/33
(3/0)(3/115)(3/61)(3/28)(3/15)
H Percentage loss of antibiotics after 24 hours of incubation at 37°C in BSS Plus based on the amount calculated (ciprofloxacin/vancomycin in %)
0/00/30/10/90/6
8/06/19/1422/726/7
0†/01/50†/0†4/72/4
4/04/31/0†4/74/4
2/06/91/0†0/60†/4
I Percentage loss of antibiotics after 72 hours of incubation at 37°C in BSS Plus based on the amount calculated (ciprofloxacin/vancomycin in %)
0/00/190/30/100/0
75/069/1273/178/476/2
9/07/715/213/920/5
2/07/39/17/117/6
5/08/80†/34/125/5