Screening, phylogenetic analysis and antibiotic sensitivity pattern of Salmonella enterica serovar Typhi isolates from typhoid asymptomatic carriers

ObjectiveTo isolate the Salmonella enterica serovar Typhi (S. typhi) from asymptomatic typhoid carriers in the local population. To assess the antibiotic sensitivity and resistant pattern of S. typhi isolates against viable antibiotics and phylogenetic analysis of S. typhi isolates on the basis of 16S rDNA gene.MethodsS. typhi was isolated and identified based on the cultural characteristics on BSA (Bismuth Sulphite Agar), MacConkey agar, agglutination test with specific antiserum and phylogenetic analysis. S. typhi isolates were tested for sensitivity and resistant pattern with a number of viable antibiotics by disc diffusion method.ResultA total of 15 bile samples were collected from the food handlers to screen the typhoid asymptomatic carriers. Positive result was yielded for 3 out of 15 samples. S. typhi isolates showed resistant to amphicillin (100%), tetracyclin (100%), rifampicin (66.5%), ofloxacin (33.5%), cloxacillin (33.5%) and susceptibility to gentamycin (100%), amikacin (100%), chloramphenicol (100%), streptomycin (100%), kanamycin (100%), cprofloxacin (100%), amoxycillin (66.5%) and ofloxacin (66.5%).ConclusionsThis study demonstrates the outbreak of typhoid fever occurs through asymptomatic carrier. In addition, this study also reveals the occurrence of considerable drug resistant among the S. typhi isolates.