Volume 27, Number 2—February 2021
Dispatch
Azithromycin-Resistant Salmonella enterica Serovar Typhi AcrB-R717Q/L, Singapore
Sophie Octavia
, Ka Lip Chew , Raymond T. P. Lin, and Jeanette W. P. Teo
, Ka Lip Chew , Raymond T. P. Lin, and Jeanette W. P. Teo
Table
Characteristics of 15 Salmonella enterica serovar Typhi subclade 4.3.1 isolates tested for azithromycin resistance, Singapore*
| Genotype and no. | Isolate name | Culture source | Patient travel history | Chromosomal azithromycin mutation | QRDR mutations | Other acquired resistance determinants | Plasmid replicon | Drug and MIC, mg/L |
||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Azithromycin BMD | Ampicillin | Cefotaxime | Ciprofloxacin | Trimethoprim/sulfamethoxazole | ||||||||
| 4.3.1.1, n = 4 | SLT0596 | Unknown | Pakistan | – | GyrA-S83F | blaTEM-1,catA1,dfrA7,sul1,sul2 | IncFIB | 2 (S) | ≥32.0 (R) | ≤1.0 (S) | 0.38 (R) | ≥320.0 (R) |
| SLT10 | Blood | Bangladesh | – | GyrA-S83F | blaTEM-1,catA1,dfrA7,sul1,sul2 | IncFIB | 4 (S) | ≥32.0 (R) | ≤1.0 (S) | 0.25 (R) | ≥320.0 (R) | |
| SLT0291 | Blood | None recent | AcrB-R717Q | GyrA-S83F | blaTEM-1,catA1,dfrA7,sul1,sul2 | IncFIB | 32 (R) | ≥32.0 (R) | ≤1.0 (S) | 0.38 (R) | ≥320.0 (R) | |
| SLT0892 | Blood | Bangladesh | AcrB-R717Q | GyrA-S83F | catA1,dfrA7,sul1 | – | 32 (R) | ≤2.0 (S) | ≤1.0 (S) | 0.38 (R) | ≥320.0 (R) | |
| 4.3.1.2, n = 8 | SLT3 | Stool | Myanmar | – | GyrA-D87N,GyrA-S83F,ParC-S80I | – | – | 4 (S) | ≤2.0 (S) | ≤1.0 (S) | >32 (R) | ≤20.0 (S) |
| SLT0096 | Stool | India | – | GyrA-D87N,GyrA-S83F,ParC-S80I | – | – | 8 (S) | ≤2.0 (S) | ≤1.0 (R) | 0.38 (R) | ≤20.0 (S) | |
| SLT2 | Stool | Philippines | – | GyrA-D87N,GyrA-S83F,ParC-S80I | – | – | 4 (S) | ≤2.0 (S) | ≤1.0 (S) | >32 (R) | ≤20.0 (S) | |
| SLT1131 | Blood | India and United States | – | GyrA-D87N,GyrA-S83F,ParC-S80I | – | – | 4 (S) | ≤2.0 (S) | ≤1.0 (S) | 8 (R) | ≤20.0 (S) | |
| SLT4 | Blood | None recent | – | GyrA-S83F | – | – | 4 (S) | ≤2.0 (S) | ≤1.0 (S) | 0.5 (R) | ≤20.0 (S) | |
| SLT0469 | Stool | India | – | GyrA-S83F | – | – | 4 (S) | ≤2.0 (S) | ≤1.0 (S) | 0.5 (R) | ≤20.0 (S) | |
| SLT0626 | Blood | India | – | GyrA-S83F | – | – | 8 (S) | ≤2.0 (S) | ≤1.0 (S) | 0.38 (R) | ≤20.0 (S) | |
| SLT11 | Blood | India | – | GyrA-S83F | – | – | 4 (S) | ≤2.0 (S) | ≤1.0 (S) | 0.38 (R) | ≤20.0 (S) | |
| 4.3.1.3, n = 3 | SLT8 | Blood | Bangladesh | – | GyrA-S83F | blaTEM-1,qnrS,sul2,tet(A) | IncFIB(K) | 4 (S) | ≤2.0 (S) | ≤1.0 (S) | 0.25 (R) | ≤20.0 (S) |
| SLT1 | Blood | Bangladesh | – | GyrA-S83F | blaTEM-1,qnrS,sul2,tet(A) | IncFIB(K) | 4 (S) | ≥32.0 (R) | ≤1.0 (S) | 4 (R) | ≤20.0 (S) | |
| SLT1105 | Blood | None recent | AcrB-R717L | GyrA-S83F | blaTEM-1,qnrS,sul2,tet(A) | IncFIB(K) | 16 (S) | ≥32.0 (R) | ≤1.0 (S) | 4 (R) | ≤20.0 (S) | |
*BMD, broth microdilution, QRDR, quinolone resistance–determining-region; R, resistant; S, susceptible; –, not detected,
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