Isolation of Salmonella enterica subspecies enterica serovar Paratyphi B dT+, or Salmonella Java, from Indonesia and alteration of the d-tartrate fermentation phenotype by disrupting the ORF STM 3356.

Salmonella enterica subspecies enterica serovar Paratyphi B [O1,4,(5),12 : Hb : 1,2] can cause either an enteric fever (paratyphoid fever) or self-limiting gastroenteritis in humans. The d-tartrate non-fermenting variant S. enterica subsp. enterica serovar Paratyphi B dT- (S. Paratyphi B) is the causative agent of paratyphoid fever, and the d-tartrate fermenting variant S. enterica subsp. enterica serovar Paratyphi B dT+ (S. Paratyphi B dT+; formerly called Salmonella Java) causes gastroenteritis. S. Java is currently recognized as an emerging problem worldwide. Twelve dT+ S. Java isolates were collected in Indonesia between 2000 and 2002. One-third of them contained Salmonella genomic island 1 (SGI1), which gives the multidrug-resistant phenotype to the bacteria. In this study, a PCR-based method to detect a single nucleotide difference responsible for the inability to ferment d-tartrate, reported elsewhere, was validated. The d-tartrate fermenting phenotype of S. Java was converted to the non-fermenting phenotype by the disruption of the ORF STM 3356, and the d-tartrate non-fermenting phenotype of the ORF STM 3356-disrupted strain and the dT- reference strain was changed to the dT+ phenotype by complementing ORF STM 3356 in trans. The results show that the dT+ phenotype requires a functional product encoded by STM 3356, and support the use of the PCR-based discrimination method for S. Paratyphi B and S. Java as the standard differentiation method.