Use of Anti-O 12 Monoclonal Antibody in Tubex Test to Identify Salmonella Bacteria from Blood Culture

Both culture and serological methods are used to diagnose enteric fever. An anti-Salmonella lipopolysaccharide O12 monoclonal antibody could be used to detect Salmonella organism directly from routine blood culture broths. Blood from 78 young outpatients suspected of having enteric fever was incubated in enrichment broth, and after 2 or 4 days, broth samplings were examined by Tubex-TP as well asa by conventional agar culture and identification. Tuber TP was performed before the culture results. Fiveteen isolates of S. Typhi and 4 isolates of S. Paratyphi A were obtained by conventional method. In all instances Tubex TP was positive, thus 100% sensitive. Twelve Escherichia coli, Alkaligenes spp and 1 Enterobacter spp were isolated. All of this case including all the 36 culture negative broths, were Tubex-negative i.e. Tubex TP was 100% specific. THus Tubes Tp is a useful adjuncts to conventional culture because they can save considerable time (>2 days), costs, and manpower. Salmonella Typhi is the causative agent of typhoid fever, a systemic infection that occurs predominantly in middle and low-income countries. The organism has remarkable genetic conservation, making strain subtyping, for local and international epidemiology, challenging. We aimed to develop a simple S. Typhi subtyping scheme based on genomic information that would offer some relevant phylogenetic information for strains circulating in endemic locations using minimal molecular biology equipment. We designed a standardized Multiplex Ligation-dependent Probe Amplification (MLPA) genotyping scheme, targeting 11 phylogenetically relevant genomic insertions/deletions (indels) across the S. Typhi genome. We validated the method by convention PCR and compared the results to Single Nucleotide Polymorphism (SNP) typing, the current gold standard used in research facilities in industrialized countries. We found that the MLPA method demonstrated approximately 90% concordance with SNP typing, with the ability to detect H58 strains and other currently relevant genotypes. Our assay additionally permitted the detection of nalidixic acid resistance inducing mutations in the DNA gyrase gene, gyrA, and the topoisomerase gene, parC, with a sensitivity of approximately 90%. The methodology we have developed is simple and reliable, providing phylogenetically and phenotypically relevant subgrouping information that has international utility. Our MLPA method can distinguish between the strains that currently dominate the global population structure of S. Typhi, offering a more sensitive and simple alternative to the subgrouping methodologies currently being used in low and middle-income countries. Abstract #: 57 Inhibition of B and T cell responses by Salmonella Pathogenicity Island II "Background: New vaccines against …