Table 1.
Antimicrobial resistance determinants of Shigella and species distributions.
| Type | Name | Resistance genes | Antimicrobial classes | Species reports |
|---|---|---|---|---|
| Chromosomal Islands | SRL-MDRE |
tetB
bla OXA-1 catA1 |
Tetracyclines Ampicillin Chloramphenicol |
S. dysenteriae15 S. flexneri8,17 S. sonnei7 |
| Tn7/Int2 |
aadA1
dfrA1 |
Aminoglycosides Trimethoprim |
S. flexneri 2a (this study) S. flexneri Xv10,33 S. sonnei6,7 |
|
| Small resistance plasmids | pSS046_spA |
sul2
strA/strB tetA |
Sulphonamides Streptomycin Tetracyclines |
S. sonnei6,32 |
| pABC-3 |
dfrA14
sul2 strB ^ |
Trimethoprim Sulphonamides — |
S. sonnei7,31 S. flexneri 3a13 S. flexneri 2a (this study) |
|
| pSFxv_3 |
strA/strB sul2 |
Streptomycin Sulphonamides |
S. flexneri Xv12 S. flexneri 2a (this study) |
|
| Large azithromycin resistance plasmids | pKSR100 |
mphA
ermB bla TEM-1B aadA5 dfrA17 sul1 |
Macrolides Macrolides Ampicillin Aminoglycosides Trimethoprim Sulphonamides |
MSM-associated: S. flexneri 3a23 S. flexneri 2a23 S. sonnei23 |
| Minor MSMA sublineage plasmid |
mphA
tetA bla TEM-1A |
Macrolides Tetracyclines Ampicillin |
S. flexneri 2a23 | |
| MSMA sublineage 3 plasmid |
mphA
dfrA1 sul1 |
Macrolides Trimpethoprim Sulphonamides |
S. sonnei23 |
^The strA gene has been interrupted by the introduction of dfra14 on this plasmid meaning no Streptomycin resistance would be conferred.