Increasing prevalence of Salmonella enterica serotype Paratyphi-A in patients with enteric fever in a periurban slum setting of Kolkata, India.

A sudden rise in the occurrence of Salmonella enterica serotype Paratyphi-A (SPTA) was noted in a longitudinal community-based study in Kolkata, India, during 2004 - 2005. We compared the incidence rate of Salmonella enterica serotype Typhi (ST) and SPTA and their antimicrobial susceptibility pattern. Rate of isolation of SPTA was 1.5 times higher than that of ST, a trend detected for the first time in that particular focus. Almost all the isolates were sensitive to Gentamycin and Norfloxacin. Most of the strains (90%) were sensitive to Ciprofloxacin. Two thirds of the strains were also sensitive to Chloramphenicol. The high occurrence of SPTA in the present study could be the signal of the emergence of SPTA as a pathogen in India. Quinolone derivatives (namely, Ciprofloxacin, Norfloxacin and Chloramphenicol) can be suggested as drugs of choice for treatment of enteric fever caused by SPTA. Future vaccination strategies should include bivalent vaccines with protection capacities against both ST as well as SPTA.