Table 4.
Characteristics of ESBL-producing E. coli strains (n = 36) isolated from mastitic cows.
| E. coli isolates | Place of isolation | Phlyo-groups | β-lactamase genes | ISCR1* | ISCR1 association with bla genes | Integron class 1 | IntI1-VR** amplicons (bp) | Gene Cassettes 5′CS -3′CS | GenBank accession numbers | R/I* phenotypes to other non β-lactam antibiotics |
|---|---|---|---|---|---|---|---|---|---|---|
| I-3 | Inner Mongolia | D | TEM-1+SHV-1 | + | + | + | 2200 | dfrA1-aacA4 | KY114582 | Cip; C; NAL; SXT; TE |
| I-4 | Inner Mongolia | A | CTX-M-15 | + | + | + | 1700 | dfrA17-aadA5 | KY114583 | Cip; C; G; NAL; SXT; TE |
| I-5 | Inner Mongolia | D | CTX-M-15+TEM-1+SHV-1 | − | − | + | 2200 | dfrA1- aacA4 | KY114584 | Cip; G; NAL; SXT; TE |
| I-6 | Inner Mongolia | A | TEM-1 | + | + | + | 1700 | dfrA17-aadA5 | KY114585 | Cip; C; G; NAL; SXT; TE |
| I-12 | Inner Mongolia | B1 | CTX-M-15+TEM-1 | + | + | − | − | − | − | Cip; G; NAL; SXT; TE |
| I-14 | Inner Mongolia | A | CTX-M-15+ SHV-1 | + | + | + | 1700 | dfrA17-aadA5 | KY114586 | Cip; C; G; NAL; SXT; TE |
| I-17 | Inner Mongolia | A | CTX-M-15 | − | − | + | 1700 | dfrA17-aadA5 | KY114587 | Cip; G; NAL; SXT; TE |
| I-18 | Inner Mongolia | A | CTX-M-15 | + | + | − | − | − | − | Cip; G; NAL; SXT; TE |
| I-22 | Inner Mongolia | D | CTX-M-15+SHV-1 | + | + | + | − | − | − | Cip; G; NAL; SXT; TE |
| I-25 | Inner Mongolia | A | CTX-M-15+TEM-1+SHV-1 | − | − | + | 1700 | dfrA17-aadA5 | KY114588 | Cip; G; NAL; SXT; TE |
| I1-1 | Inner Mongolia | A | CTX-M-14 | + | + | + | 1800 | dfrA17-aada4 | KY114589 | − |
| I1-2 | Inner Mongolia | A | TEM-1 | + | + | + | − | − | − | G; TE |
| I1-3 | Inner Mongolia | A | TEM-1 | + | − | − | − | − | − | − |
| I1-4 | Inner Mongolia | A | CTX-M-15 | − | − | + | 1700 | dfrA17-aadA5 | KY114590 | − |
| I1-5 | Inner Mongolia | A | CTX-M-15 | _ | _ | _ | _ | _ | _ | NAL |
| I1-7 | Inner Mongolia | B1 | CTX-M-55+TEM-1 | _ | _ | + | 1700 | dfrA17-aadA5 | KY114591 | Cip; C; G; NAL; SXT; TE |
| I1-8 | Inner Mongolia | A | CTX-M-14 | − | − | + | 1800 | dfra17-aada4 | KY114592 | C; G; NAL; SXT; TE |
| I1-11 | Inner Mongolia | B1 | TEM-1 | − | − | + | 1700 | dfrA17-aadA5 | KY114593 | C; G; NAL; SXT; TE |
| I2-1 | Inner Mongolia | A | CTX-M-15+TEM-1 | − | − | + | 1700 | dfrA17-aadA5 | KY114594 | Cip; C; G; NAL; SXT; TE |
| I2-2 | Inner Mongolia | A | TEM-1 | − | − | + | 1700 | dfrA17-aadA5 | KY114595 | C; G; NAL; SXT; TE |
| I2-3 | Inner Mongolia | A | CTX-M-14+TEM-1 | − | − | + | 1800 | dfra17-aada4 | KY114596 | C; G; NAL; SXT; TE |
| I3-1 | Inner Mongolia | B2 | CTX-M-15 | + | + | + | 1700 | dfrA17-aadA5 | KY114597 | C; G; NAL; SXT; TE |
| I3-2 | Inner Mongolia | B2 | CTX-M-15 | + | + | + | 1700 | dfrA17-aadA5 | KY114598 | C; G; NAL; SXT; TE |
| G-1 | Guangdong | A | CTX-M-15 | + | + | + | 1700 | dfrA17-aadA5 | KY114599 | Cip; C; NAL; SXT; TE |
| G-2 | Guangdong | A | CTX-M-15+TEM-1 | + | + | + | 1700 | dfrA17- aadA5 | KY114600 | C; NAL; SXT; TE |
| J-4 | Jiangsu | D | CTX-M-15+TEM-1 | + | + | + | − | − | − | C; G; NAL; SXT; TE |
| J-5 | Jiangsu | D | CTX-M-15+TEM-1 | + | + | + | − | − | − | C; G; NAL; SXT; TE |
| Hb2-4 | Hebei | D | TEM-1 | − | − | + | 2000 | dfrA17-aadA5 | KY114601 | C; G; NAL; SXT; TE |
| Hb3-1 | Hebei | A | CTX-M-15 | + | + | + | 1000 | aadA1 | KY114602 | Cip; C; G; NAL; SXT; TE |
| L-1 | Liaoning | A | CTX-M-15+TEM-1 | + | + | + | 1700 | dfrA17-aadA5 | KY114603 | C; G; NAL; SXT; TE |
| N-1 | Ningxia | A | CTX-M-3+TEM-1 | − | − | + | 1300 | aadA5 | KY114604 | TE |
| H-5 | Heilojinag | A | SHV-12 | + | + | − | − | − | − | − |
| Hn-6 | Henan | A | CTX-M-15 | − | − | − | − | − | − | C; TE |
| Hn1-2 | Henan | A | CTX-M-1 | + | + | + | 1700 | dfrA17-aadA5 | KY114605 | G; NAL |
| Hn1-6 | Henan | A | CTX-M-15+TEM-1 | + | − | + | 1700 | dfrA17-aadA5 | KY114606 | G; NAL; SXT; TE |
| Hn1-7 | Henan | A | CTX-M-15+TEM-1 | + | + | + | 1700 | dfrA17-aadA5 | KY114607 | G; NAL; SXT; TE |
R/I, Resistance/Intermediary; aacA4, aminoglycoside 6′-N-acetyltransferase; aadA, aminoglycoside adenyltransferase; dfrA1, dihydrofolate reductase type A; dfrA17, dihydrofolate reductase DHFRXVII; Cip, ciprofloxacin; C, chloramphenicol; G, gentamicin; NAL, nalidixic acid; SXT, trimethoprim/sulphamethoxazole; TE, tetracycline.
*
ISCR1: Insertion sequence common region 1.
**
IntI1-VR-: class 1 integrons variable regions, approximate size of base pairs deduced from running the amplicons on 1% agarose gel and sequencing the amplicon.