1. Quinolone low-level resistance in Salmonellae and other Enterobacteriaceae
Niels Frimodt-Møller
National Center of Antimicrobials and Infection Control
Statens Serum Institut
Copenhagen, Denmark

2. Salmonella spp., nalidixic acid S-R and ciprofloxacin MIC
Hartmann, Skov & Frimodt-Møller
No. of
Isolates
MIC
mg/l
Breakpoints / interpretive zone diameters
NCCLS: R 4; S 1
SRGA: R > 1; S < 0.063
Nalidixic acid - Susceptible
No mutations 15
0.063
( )
Not genotyped 24
0.032
Nalidixic acid – Intermediate 1
Nalidixic acid – Resistant
Nalidixic acid - Resistant
+ mutations 16 0,

3. Salmonella spp: MIC for nalidixan og ciprofloxacin bestemt med mikrotiter og Etest
Hartmann, Skov & Frimodt-Møller

4. Salmonella spp. and quinolone resistance
Hartmann, Skov & Frimodt-Møller

5. Salmonella spp. and quinolone resistance
Hartmann, Skov & Frimodt-Møller

6. Salmonella spp. and quinolone resistance
Hartmann, Skov & Frimodt-Møller

7. Salmonella spp. and quinolone resistance
Hartmann, Skov & Frimodt-Møller

8. Salmonella spp. and quinolone resistance
Hartmann, Skov & Frimodt-Møller

9. Ciprofloxacin-resistance in Salmonella: Clinical failures

10. Quinolone resistance in E. coli Ruiz et al
Quinolone resistance in E. coli Ruiz et al. Diagn Microbiol Infect Dis 2002, 42:
No. of Isolates
Ciprofloxacin
MIC
Nalidixic acid
% Nal - R 2
0.06 17
0.12 8 47 39
0.25 32 82 26
0.5 18 69 33 1 31 94
4 strains were Cip-R (0.25) but Nal-S -> None grew over their Cip-MIC

11. Quinolone resistance and Enterobacteriaceae
High correlation between Nal-R and Cipro-I/R (and other quinolones)
Cipro MIC > mg/l correlates with poor clinical outcome of Cipro treatment, i.e. Cipro-S should remain < mg/l
Cipro-R and Nal-S occurs, but so far no clinical relevance
A Nalidixic acid disk/tablet is a good screening method for Cipro-I/R