Salmonella of Indian origin: pseudo-susceptibility to fluoroquinolones

We report the case of a patient presenting with typhoid fever after returning from a stay in India. This infection was not cured with a course of ciprofloxacin, due to a reduced susceptibility of the bacteria to the drug. This decreased susceptibility to fluoroquinolones was not detected by the antibiogram, but the MIC for nalidixic acid was greater than 32 mg/l. This case suggests using a third generation cephalosporin instead of a quinolone, for people coming from a high-risk zone. It also suggests that the MIC for nalidixic acid and for norfloxacin can be used as the first clue for a reduced susceptibility to fluoroquinolones.