TABLE 3.
Characterization of integrons, cassette arrays, and integron-associated antibiotic resistance in 59 Enterobacteriaceae isolates
| Integrons and cassette arraysab | Site of collectionc | Incidence by organism
|
Total | No. of isolates resistant to antibiotic:d
|
|||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| E. coli | Klebsiella sp. | Proteus sp. | AM | CM | GM | KM | SM | SU | TC | TP | |||
| Class 1 integrons | |||||||||||||
| aadA1 | H1 (17), H2, H3, H4, H5 (3), C2 | 23 | 1 | 0 | 24 | 22 | 2 | 1 | 3 | 22 | 23 | 7 | 3 |
| dfrA17-aadA5 | H1 (2), H2, H4 | 4 | 0 | 0 | 4 | 4 | 1 | 0 | 0 | 4 | 4 | 2 | 4 |
| dfrA12-aadA2 | H1, H2 (2) | 3 | 0 | 0 | 3 | 3 | 3 | 3 | 1 | 3 | 2 | 3 | 3 |
| dfrA5 | H1, H2, H3 | 2 | 0 | 1 | 3 | 2 | 0 | 0 | 0 | 2 | 3 | 1 | 3 |
| aadB | H1, H2 (2) | 0 | 3 | 0 | 3 | 3 | 1 | 2 | 2 | 0 | 3 | 1 | 3 |
| dfrA1-aadA1 | H1 | 0 | 0 | 1 | 1 | 1 | 1 | 1 | 0 | 1 | 1 | 1 | 1 |
| aadA1-aadA5 | H5 | 1 | 0 | 0 | 1 | 1 | 0 | 0 | 0 | 0 | 1 | 0 | 1 |
| drfB2-orfA | H1 | 1 | 0 | 0 | 1 | 1 | 1 | 0 | 1 | 1 | 1 | 1 | 1 |
| dfrA12 | H1 | 1 | 0 | 0 | 1 | 1 | 0 | 0 | 0 | 1 | 1 | 1 | 1 |
| Class 1 (undetermined) | H1 (2) | 1 | 1 | 0 | 2 | 2 | 0 | 0 | 1 | 1 | 2 | 1 | 2 |
| Two class 1 integrons | |||||||||||||
| aadB + aadA2 | H1 (2), H3 (2) | 0 | 4 | 0 | 4 | 4 | 3 | 3 | 3 | 3 | 4 | 3 | 3 |
| Class 1 and 2 integrons | |||||||||||||
| aadA1 + drfA1-sat1-aadA1 | H3, H4, H6 | 3 | 0 | 0 | 3 | 3 | 1 | 0 | 0 | 3 | 3 | 3 | 3 |
| dfrA12-aadA2 + drfA1-sat1-aadA1 | H1, C1 | 1 | 0 | 1 | 2 | 1 | 2 | 0 | 0 | 2 | 1 | 2 | 2 |
| dfrA5-ereA2 + drfA1-sat1-aadA1 | H1 | 1 | 0 | 0 | 1 | 1 | 1 | 0 | 1 | 1 | 1 | 1 | 1 |
| Class 1 (undetermined) + drfA1-sat1-aadA1 | H2 | 0 | 0 | 1 | 1 | 0 | 0 | 0 | 1 | 0 | 1 | 1 | 1 |
| Class 2 integron | |||||||||||||
| drfA1-sat1-aadA1 | H1, H3, H4 (2), C1 | 3 | 0 | 2 | 5 | 4 | 2 | 0 | 0 | 4 | 3 | 4 | 5 |
| Total (% of total) | 44 (74.6) | 9 (15.2) | 6 (10.2) | 59 (100) | 53 (89.8) | 18 (30.5) | 10 (16.9) | 13 (22.0) | 48 (81.3) | 54 (91.5) | 32 (54.2) | 37 (62.7) | |
a
Class 2 cassettes are underlined.
c
Numbers of organisms isolated are shown in parentheses if more than one. H, hospital; C, community clinic.
d
Bold, antibiotic relevance to integron-associated resistance genes. AM, ampicillin; CM, chloramphenicol; GM, gentamicin; KM, kanamycin; SM, streptomycin; SU, sulfafurazole; TC, tetracycline; TP, trimethoprim.