Volume 15, Number 1—January 2009
Dispatch
Variation in Antimicrobial Resistance in Sporadic and Outbreak-related Salmonella enterica Serovar Typhimurium
, Mia Torpdahl, Steen Ethelberg, and Anette M. Hammerum
Table 1
Antimicrobial resistance profile of 323 clinical Salmonella enterica serovar Typhimurium DT104 isolates, Denmark, 2003–2006*
| Phenotype | SGI1 genotype† | Unique types, no. strains (%) | All isolates, no. (%) |
|---|---|---|---|
| ACSSuT‡ | SGI1§ | 122 (84) | 251 (78) |
| ACSSuTTm¶ | SGI1-A | 5 (3) | 9 (3) |
| ASu | SGI1-B | 4 (3) | 24 (7) |
| SSu | SGI1-C | 3 (2) | 11 (3) |
| ASSuTTm | SGI1-C | 1 (0.7) | 2 (0.6) |
| ASSu | SGI1-B | 1 (0.7) | 2 (0.6) |
| ACST# | SGI1 | 1 (0.7) | 1 (0.3) |
| SSuT | Not present | 1 (0.7) | 3 (0.9) |
| Sensitive |
Not present |
8 (6) |
20 (6) |
| Total | 146 (100) | 323 (100) |
*One isolate per multilocus variable number of tandem repeats analysis (MLVA) and antimicrobial resistance profile is represented in the data set of 146 strains with unique types. A, ampicillin; C, chloramphenicol; S, streptomycin; Su, sulfonamides; T, tetracycline; Tm, trimethoprim.
†SGI, Salmonella genomic island. Genotype determined by the SGI1-related PCR assays described in the text (1 isolate per “unique type”); see Table 2 for selected details.
‡Additional antimicrobial-drug resistances: nalidixic acid and ciprofloxacin (22 strains), amoxicillin/clavulanic acid (3 strains), gentamicin (1 strain).
§Only a small subset of 10 ACSSuT strains was tested by PCR for the presence of SGI1 genes.
¶Additional antimicrobial-drug resistances: nalidixic acid, ciprofloxacin, and gentamicin (1 strain).
#Additional antimicrobial-drug resistances: nalidixic acid and ciprofloxacin.