A monoclonal antibody-based latex agglutination (MAb-LA) test was employed for the rapid identi®cation of Burkholderia pseudomallei in blood culture¯uid from patients with community-acquired septicaemia. These patients were admitted to 12 hospitals in the northeastern part of Thailand which is a region known to be endemic for melioidosis. Blood samples were collected and immediately added to the blood culture bottles which were incubated in either automated (®ve hospitals) or manual (seven hospitals) culture systems. Of a total of 1369 culture-positive specimens, 204 specimens were culture-positive for B. pseudomallei. Of those, 194 (95%) were positive by MAb-LA and the type of blood culture system did not affect positivity rates. The performance of the MAb-LA test on these specimens was highly satisfactory compared with culture detection and con®rmation by biochemical test, with 95.1% sensitivity, 99.7% speci®city and 98.8% and 99.2% for positive and negative predictive values, respectively. The method described is highly reproducible, simple to perform even by inexperienced laboratory personnel and does not require expensive or elaborate equipment.
Burkholderia pseudomallei is the causative agent of melioidosis, a life-threatening disease that affects both humans and animals. This bacterium is able to survive and multiply inside both phagocytic and nonphagocytic cells. We recently reported that mouse macrophages infected with B. pseudomallei fail to produce a significant level of inducible nitric oxide synthase (iNOS), a crucial enzyme needed for the cells to control the intracellular growth of this bacterium. In the present study, we extended our investigation to demonstrate that, unlike other gram-negative bacteria that have been investigated, B. pseudomallei only minimally activates beta interferon (IFN-) production; this minimal activation leads to a low level of interferon regulating factor 1 (IRF-1) in the macrophages, in parallel with poor iNOS expression. Adding exogenous IFN- to the system could upregulate IRF-1 production, which in turn could enhance iNOS expression in the B. pseudomallei-infected macrophages and lead to suppression of the intracellular growth of this bacterium. Taken together, these results imply that the failure of macrophages to successfully control the growth and survival of intracellular B. pseudomallei is related, at least in part, to the defective production of IFN-, which modulates the ability of macrophages to synthesize iNOS.
Heterogeneous patterns were obtained for lipopolysaccharide (LPS) from 1,327 Burkholderia pseudomallei isolates by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, silver staining, and immunoblot analysis. Two LPS serotypes (A and B) possessing different ladder profiles and a rough LPS without ladder appearances were identified. All three LPS types were antigenically distinct by immunoblotting. The predominant type A (97%) produced the lowest amount of biofilm. The two less common types (smooth type B and rough type) were found more in clinical than environmental isolates and more in Australian isolates than Thai isolates. These isolates were more often associated with relapse than with primary infection.
Abstract. A rapid method for the identification and differentiation of Burkholderia pseudomallei and Burkholderia thailandensis colonies is described. It consists of simultaneous use of 2 monoclonal antibody-based latex agglutination test systems. The anti-lipopolysaccharide test reacts with both species, whereas the anti-exopolysaccharide reacts only with B. pseudomallei. Compared with classical biochemical tests, the method is highly reproducible and accurate. It is particularly useful for the identification of the organisms in environmental specimens, which may contain both of these Burkholderia species.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.