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It is suggested that Salmonella typhi resides mostly in hepatobiliary system especially in gallbladder in chronic typhoid carriers. It is not very clear whether in gallbladder lumen or on its wall or in liver. However, we had been successful in detecting S. typhi in liver by PCR targeting flagellin gene sequences. Therefore, in the present study, we tried to isolate the bacterium from liver tissue collected from dead bodies brought for post mortem examination. We could isolate S. typhi in 2 of 20 such liver tissues examined by using conventional isolation techniques. The isolates were identified by routine phenotypic characters and were confirmed by amplification and sequencing of two conserved genes i.e. 16S rDNA and flagellin (fliC) gene followed by blasting on www.ncbi.nlm.nih.gov., (Copyright © 2011 Elsevier B.V. All rights reserved.)

For detection of chronic typhoid carriers, nested PCR targeting flagellin the gene of Salmonella enterica subspecies enterica serotype Typhi was carried out on DNA extracted from hepatobiliary specimens from 424 autopsies which were apparently free from gallbladder pathology on postmortem examination. The second study population was 508 healthy volunteers, who did not suffer from typhoid fever during the preceding year and whose sera were subjected to detection of carriage by estimation of Vi antibody levels using an indirect hemagglutination assay. Males of both study populations had comparable rates of detection by the two methods, 6.3% by PCR and 4.1% by Vi serology. Similarly, females in both study groups had comparable frequency of detection of chronic typhoid carriage using the two methods, ie 13.1% by PCR and 15.1% by Vi serology. S. Typhi specific immunosuppression could be speculated in females of 51-60 years as only 40% were positive by Vi serology against 100% by nested PCR. Vi serology may be recommended for community based detection of chronic typhoid carriers.

Background: Although well studied the association between chronic typhoid carrier state and carcinoma of the gallbladder (CaGB) remains unproven., Methodology: The study was performed at a tertiary care medical center in North India and involved 52 patients with CaGB, 223 patients with benign gallbladder diseases, 508 healthy individuals and, 424 corpses. For the detection of Salmonella enterica serovar Typhi, hepatobiliary specimens were subjected to DNA extraction for specific nested- PCR amplification of the S. Typhi flagellin gene. Anti-Vi S. Typhi antibodies were detected in serum samples from patients by indirect haemagglutination., Results: Thirty five of the 52 (67.3%) CaGB patients were PCR-positive for the S. Typhi flagellin gene; significantly higher than for patients with benign gallbladder diseases (95/223, 42.6%; p<0.01) and corpses (35/424, 8.2%; p<0.001). The numbers of individuals that had significant anti-Vi antibody titres (> or = 160) in their serum were 20/52 (38.5%) for CaGB patients, 31/223 (13.9%) for patients with benign gallbladder diseases, and 47/508 (9.2%) for healthy individuals., Conclusions: Specific nested-PCR amplification of the S. Typhi flagellin gene in hepato-biliary specimens was more sensitive for detection of S. Typhi carriage than anti-Vi antibody titres in serum. The results demonstrate an association between typhoid carriage and gallbladder diseases, both CaGB and benign. S. Typhi specific immunosuppression is also suggested in patients with gallbladder diseases.