Re-emerging chloramphenicol sensitivity and emerging low level ciprofloxacin resistance among Salmonella enterica serotype typhi isolates in North India.

Ciprofloxacin has become the antibiotic of choice for the treatment of typhoid fever with the emergence and worldwide spread of Salmonella enterica typhi strains resistant to chloramphenicol. However, the rampant use of ciprofloxacin gradually led to an increase in its minimum inhibitory concentration against S. enterica typhi. This threatened its therapeutic efficacy and resulted in the re-emergence of chloramphenicol-sensitive S. enterica typhi strains.