Isolation, phage typing and antibiogram of Salmonella from man and animals in northeastern India

Salmonella is an important zoonotic pathogen and its prevalence in the animals acts as a continuous threat to man. The present study was carried out to report the isolation along with the serotypes, phage types and antibiogram pattern of Salmonella among man, livestock and poultry in the northeastern India.

A total of 654 samples from diarrhoeic livestock and humans were processed for the isolation of Salmonella. All the isolates were subjected to antibiogram studies against 15 antimicrobials. Representative isolates of S. Typhimurium and S. Enteritidis were phage typed.

Ninety five isolates of Salmonella enterica belonging to 5 serotypes- S. Typhimurium, S. Enteritidis, S. Gallinarum, S. Paratyphi B and S. Bareilly were obtained with an overall prevalence rate of 14.40 per cent. S. Typhimurium isolates were distributed among four phages- DT003, DT004, DT096 and DT193 and all the S. Enteritidis isolates belonged to a single phage type, PT13a/7. Interspecies sharing of the phages was observed. Norfloxacin, enrofloxacin, gentamycin and ciprofloxacin were most effective, whereas, doxycycline, ampicillin, amoxycillin and tetracycline were relatively less effective.

Our findings showed that three of the five serovars as well as some of the phage types of these serovars were shared by animals and humans indicating the zoonotic potential of the organism. Thus, it is imperative that salmonellosis control measures adopted for humans should give adequate importance to its control in the animals particularly their products.