Table 1. Antibiotic susceptibility patterns of toxigenic and non-toxigenic V. cholerae O139 isolates.
| Antibiotic | Breakpoints(µg/ml) | Toxigenic (n=290) | Non-toxigenic (n=50) | ||
| R(%) | S(%) | R(%) | S(%) | ||
| Ampicillin | S<=8 R>=32a | 211(72.7) | 79(27.3) | 31(62.0) | 19(38.0) |
| Cephalothin | S<=8 R>=32b | 46(15.9) | 244(84.1) | 3(6.0) | 47(94.0) |
| Cefuroxime | S<=8 R>=32b | 0(0) | 290(100.0) | 0(0) | 50(100.0) |
| Ceftriaxone | S<=8 R>=64b | 0(0) | 290(100.0) | 0(0) | 50(100.0) |
| Cefixime | S<=1 R>=4b | 0(0) | 290(100.0) | 0(0) | 50(100.0) |
| Nalidixic acid* | S<=16 R>=32b | 241(83.1) | 49(16.9) | 13(26.0) | 37(74.0) |
| Ciprofloxacin | S<=1 R>=4b | 16(5.5) | 274(94.5) | 0(0) | 50(100.0) |
| Tetracycline* | S<=4 R>=16a | 242(83.4) | 48(16.6) | 8(16.0) | 42(84.0) |
| Doxycycline | S<=4 R>=16b | 39(13.5) | 251(86.5) | 1(2.0) | 49(98.0) |
| Chloramphenicol* | S<=8 R>=32a | 193(66.5) | 97(33.5) | 5(10.0) | 45(90.0) |
| Erythromycin | S<=.5 R>=8b | 273(94.1) | 17(5.9) | 49(98.0) | 1(2.0) |
| Azithromycin* | S<=2 R>=8b | 146(50.3) | 144(49.7) | 1(2.0) | 49(98.0) |
| Kanamycin* | S<=16 R>=64b | 231 (79.6) | 59(20.4) | 6(12.0) | 44(88.0) |
| Streptomycin | S<=4 R>=16b | 284(97.9) | 6(2.1) | 44(88.0) | 6(12.0) |
| Polymyxin B | S<=2 R>=4b | 287(99.0) | 3(1) | 43(86.0) | 7(14.0) |
| Trimethoprim-Sulfamethoxazole* | S<=2 R>=4a | 263(90.7) | 27(9.3) | 16(32.0) | 34(68.0) |
a
Breakpoints are based on the CLSI standards for V. cholerae.
b
Other breakpoints refer to the CLSI criteria for Enterobacteriaceae.
R: includes intermediate and resistance; S: sensitivity.
A single asterisk (*) indicates that the rates of resistance among the toxigenic O139 strains was significantly different (P<0.01, χ2 test) from the non-toxigenic strains.