Systematic Review and Consensus Guidelines for Environmental Sampling of Burkholderia pseudomallei

Abstract

Background Burkholderia pseudomallei, a Tier 1 Select Agent and the cause of melioidosis, is a Gram-negative bacillus present in the environment in many tropical countries. Defining the global pattern of B. pseudomallei distribution underpins efforts to prevent infection, and is dependent upon robust environmental sampling methodology. Our objective was to review the literature on the detection of environmental B. pseudomallei, update the risk map for melioidosis, and propose international consensus guidelines for soil sampling.Methods/Principal FindingsAn international working party (Detection of Environmental Burkholderia pseudomallei Working Party (DEBWorP)) was formed during the VIth World Melioidosis Congress in 2010. PubMed (January 1912 to December 2011) was searched using the following MeSH terms: pseudomallei or melioidosis. Bibliographies were hand-searched for secondary references. The reported geographical distribution of B. pseudomallei in the environment was mapped and categorized as definite, probable, or possible. The methodology used for detecting environmental B. pseudomallei was extracted and collated. We found that global coverage was patchy, with a lack of studies in many areas where melioidosis is suspected to occur. The sampling strategies and bacterial identification methods used were highly variable, and not all were robust. We developed consensus guidelines with the goals of reducing the probability of false-negative results, and the provision of affordable and ‘low-tech’ methodology that is applicable in both developed and developing countries.Conclusions/SignificanceThe proposed consensus guidelines provide the basis for the development of an accurate and comprehensive global map of environmental B. pseudomallei.

Melioidosis in Africa: Should we be Looking more Closely?

“…The definition is based on the recently published consensus guideline for soil sampling for B. pseudomallei [23]. In 1936, the first potential presence of Whitmore's disease was reported in a dead pig from Madagascar [16].…”

“…To that end, it is also important to note that in the early years (probably to up to the mid-1970s), diagnostic methods to identify the various Burkholderia species, or the confirmation of the presence of B. pseudomallei were not fully established; and that in earlier reports the techniques used were often not provided in the literature. Recently, guidelines were proposed for optimizing strategies to determine the presence of this organism in soil [23,31]. One of the primary aims of these guidelines is to lower probability of false negativity (if insufficient samples are taken or inappropriate techniques are used) or false positivity (if methods are not adequate to exclude related Burkholderia species) results from environmental studies.…”

“…One of the primary aims of these guidelines is to lower probability of false negativity (if insufficient samples are taken or inappropriate techniques are used) or false positivity (if methods are not adequate to exclude related Burkholderia species) results from environmental studies. Moreover, propagation of low cost and 'low-tech' methods aims at making these methodologies applicable in resource-poor settings [23]. Serological methods applied in epidemiological studies [20,[27][28] and case reports [6,9] differ.…”

“…It should be noted that, even with such facilities available, B. pseudomallei could be mistaken as contamination and may be misidentified by standard identification methods as API20NE and more recent methods such as automated microbial identification systems MALDI techniques. Figure 2 provides an overview of the prevalence of B. pseudomallei in Africa as known up to date, in which environmental samples and cases in animals and humans are categorized as definite, probable or possible [23,31].…”

Fatal Melioidosis in a Newborn from Hainan, China

“…Subsequent cultures of possible respiratory infectious microorganisms, including B. pseudomallei, Mycobacterium tuberculosis, Klebsiella pneumoniae, Pseudomonas aeruginosa, Mycoplasma, Chlamydia, and human immunodeficiency virus from blood or sputum specimens, were all negative. 1 In addition, 16S rDNA amplification on his blood specimen was also negative. Persons who had any contact with the newborn all appeared healthy with no suspected symptoms, and cultures of their blood or sputum specimens were all negative for B. pseudomallei.…”