TABLE 2.
Phenotypic and molecular characteristics of Nalr S. enterica serotype Typhi isolates in Vietnam from 1996 to 2004a
| Region | Yr | No. of isolates | Antimicrobial resistance pattern | MICs (mg/liter)
|
Phage type | PFGE combined type (XbaI-SpeI) | Ribotype | gyrA mutation(s) | |
|---|---|---|---|---|---|---|---|---|---|
| Nal | Cip | ||||||||
| South | 1996-1998 | 22 | ASCTeSulSxtNal (22) | 64 (1), 128 (4), 256 (15), 1,024 (2) | 0.125 (1), 0.25 (13), 0.5 (8) | UT (13), UVS (6), Evar (2), E1 (1) | X3a-S6a (8), X1a-S1a (4), X3a-S9 (1), X3b-S6b (2), X5c-S4 (1), X20-S27 (1), X21-S19a (1), X23-S22 (1), X11a-S5a (1), X11b-S5b (1), X14-S19b (1) | 3a (17), 341 (1), S007 (1), ND (3) | Phe83 (16), Tyr83 (1), ND (5) |
| 1999-2001 | 17 | ASCTeSulSxtNal (16), Nal (1) | 128 (3), 256 (3), 512 (1), 1,024 (1), >1,024 (9) | 0.25 (7), 0.5 (10) | UVS (6), E1 (5), Evar (4), UT (2) | X3a-S6a (4), X1a-S1a (3), X3b-S6b (3), X5a-S4 (1), X5a-S1b (1), X1a-S2 (1), X1b-S1b (1), X17-S17 (1), X18-S18 (1), X19-S1b (1) | 3a (11), S007 (1), 142 (1), ND (4) | Phe83 (11), ND (6) | |
| 2002-2004 | 31 | Nal (18), ASCTeSulSxtNal (11), ASTeSulSxtNal (1), CTeTmpNal (1), | 256 (11), 512 (5), >1,024 (15) | 0.125 (1), 0.25 (5), 0.5 (25) | UT (20), E1 (7), Evar (2), UVS (2), | X1b-S1b (16), X1a-S1a (3), X8-S12 (4), X5b-S11 (2), X1b-S5b (1), X3a-S6a (1), X3b-S6b (1), X5c-S15 (1), X6-S1a (1), X9-S13 (1) | 3a (14), 73/34/8 (4), 177 (2), 23a (1), ND (10) | Phe83 (22), ND (9) | |
| Center | 1996-1998 | 0 | |||||||
| 1999-2001 | 5 | ASCTeSulSxtNal (4), ANal (1) | 256 (1), >1,024 (4) | 0.5 (5) | UT (3), UVS (2) | X3a-S6a (3), X3b-S6b (2) | 3a (4), ND (1) | Phe83 (4), ND (1) | |
| 2002-2004 | 5 | ASCTeSulSxtNal (3), Nal (2) | 256 (1), >1,024 (4) | 0.25 (1), 0.5 (4) | UVS (3), UT (2) | X3b-S6b (2), X3b-S7 (1), X1a-S1a (1), X26-S14 (1) | 3a (4), ND (1) | Phe83 (4), ND (1) | |
| North | 1996-1998 | 8 | ASCTeSulSxtNal (8) | 1,024 (8) | 0.06 (1), 0.25 (4), 0.5 (3) | E1 (4), Evar (4) | X1a-S1a (3), X1b-S1b (1), X24-S24 (1), X5c-S4 (1), X11b-S16 (1), X16-S20 (1), | 3a (4), S007 (1), 350 (1), 351 (1), ND (1) | Phe83 (4), Tyr83 (2), ND (2) |
| 1999-2001 | 1 | ASCTeSulSxtNal | 1,024 (1) | 0.25 (1) | E1 (1) | X1a-S1a (1) | 3a (1) | Phe83 (1) | |
| 2002-2004 | 2 | ASCTeSulSxtNal (1), Nal (1) | 128 (1), >1,024 (1) | 0.125 (1), 0.5 (1) | E1 (2) | X1a-S1a (1), X13-S1b (1) | 3a (2) | Phe83 (1), Gly87 (1) | |
a
Numbers in parentheses refer to the number of isolates. Abbreviations: UVS, untypeable Vi isolate; UT, not typeable (Vi negative); var, variant; A, amoxicillin; S, streptomycin; C, chloramphenicol; Te, tetracycline; Sul, sulfonamides; Tmp, trimethoprim; Sxt, sulfamethoxazole-trimethoprim; Nal, nalidixic acid; ND, not determined.