Age-related clinical and microbiological characteristics of enteric fever in India

A retrospective, hospital-based study at Safdarjang Hospital, India, was undertaken between January 1999 and December 2003 to estimate age-related epidemiological, clinical and microbiological characteristics in enteric fever cases. A total of 750 blood-culture-proven cases of enteric fever were studied. The majority of cases occurred in children aged 5-12 years and 24.8% of cases were in children up to 5 years of age. Salmonella serotypes showed an age-related predilection, with paratyphoid fever more common in adults. Classically-described clinical features of the disease were comparable among patients under and above 5 years of age. Hepatomegaly, anaemia and complications in general were more frequent in children up to 5 years of age. The antimicrobial resistance pattern, irrespective of Salmonella serotype, did not reveal a statistically significant difference across age groups for the different antibiotics tested. Multidrug resistance was seen only in Salmonella enterica serotype Typhi but not in S. Paratyphi A isolates. However, resistance to nalidixic acid was comparable in both serotypes. Age-related differences of serotype isolation rates, clinical presentation and associated complications are noteworthy for better case management and policy planning. More epidemiological studies regarding reasons for age-related differential serotype patterns would enable and guide public health strategies to contain enteric fever in endemic locations.