TABLE 5.
Single and multidrug resistance patterns in E. coli from the irrigation return flows (IRFs) and background canal site (MLC).
| Resistance pattern | No. of antimicrobials | No. of drug classes |
No. of isolates |
|
| IRFs | MLC | |||
| (n = 171) | (n = 16) | |||
| Pan-susceptible | 0 | 0 | 133 | 8 |
| Azi | 1 | 1 | 1 | 0 |
| Fis | 1 | 1 | 1 | 1 |
| Fox | 1 | 1 | 1 | 0 |
| Str | 1 | 1 | 1 | 0 |
| Tet | 1 | 1 | 9 | 0 |
| AmpTet | 2 | 2 | 1 | 0 |
| Aug2Fis | 2 | 2 | 1 | 0 |
| ChlTet | 2 | 2 | 1 | 0 |
| CipNal | 2 | 2 | 1 | 1 |
| StrTet | 2 | 2 | 1 | 0 |
| XnlNal | 2 | 2 | 1 | 0 |
| AmpStrTet | 3 | 3* | 1 | 0 |
| AxoCipFis | 3 | 3* | 1 | 0 |
| Aug2AmpFox | 3 | 2 | 7 | 1 |
| Aug2FisTet | 3 | 3* | 2 | 0 |
| CipTetStr | 3 | 3* | 1 | 0 |
| FisTetStr | 3 | 3* | 1 | 0 |
| AmpNalFisSxt | 4 | 3* | 1 | 0 |
| AxoCipNalFis | 4 | 3* | 1 | 0 |
| FisStrSxtTet | 4 | 3* | 1 | 0 |
| AmpChlStrFisTet | 5 | 5* | 3 | 0 |
| Aug2AmpAxoFo Xnl | 5 | 2 | 0 | 1 |
| CipNalFisTetSxt | 5 | 3* | 0 | 1 |
| ChlCipNalStrFis TetSxt | 7 | 5* | 0 | 2 |
| AmpXnIAxoChlCip NalStrFisTetSxt | 10 | 7* | 0 | 1 |
Aug2, amoxicillin/clavulanic acid; Amp, ampicillin; Azi, azithromycin; Fox, cefoxitin; XnL. ceftiofur; Axo, ceftriaxone; Chl, chloramphenicol; Cip, ciprofloxacin; Gen, gentamicin; Nal, nalidixic acid; Str, streptomycin; Fis, sulfisoxazole; Tet, tetracyline; Sxt, trimethoprim/sulfamethoxazole; Pan-susceptible, susceptible to all antimicrobials tested.
*Denotes multidrug resistance based on resistance to antimicrobials in three or more drug classes.