Epidemiol. Infect. (1997), 118, 137–148 Copyright # 1997 Cambridge University Press Characterization of Burkholderia pseudomallei and Burkholderia pseudomallei-like strains P.J.BRETT, D.DESHAZER D. E. WOODS* Department of Microbiology and Infectious Diseases, Faculty of Medicine, University of Calgary Health Sciences Centre, 3330 Hospital Drive, N.W., Calgary, Alberta, Canada T2N 4N1 (Accepted 22 November 1996) SUMMARY Previous reports in the literature suggest that Burkholderia pseudomallei strains can be differentiated on the basis of animal virulence. Twenty environmentally and clinically derived isolates of Burkholderia pseudomallei were examined for the production of exoenzymes, morphological and biochemical phenotypes and virulence for Syrian golden hamsters. The partial sequence of the 16S ribosomal RNA [rRNA] genes from a number of these strains was also determined. Based upon these observations, it is suggested that highly virulent Burkholderia pseudomallei strains are true Burkholderia pseudomallei strains. The DNA sequences of the 16S rRNA genes of the true Burkholderia pseudomallei strains were identical to the published sequences for Burkholderia pseudomallei while differences were revealed between the published sequences and those of the lowly virulent strains. Thus, these latter strains have been designated as Burkholderia pseudomallei-like organisms since they demonstrate significant differences in exoenzyme production, hamster virulence and 16S rRNA gene sequences. INTRODUCTION Burkholderia pseudomallei, the causative agent of melioidosis [1–3], is a bacterial pathogen endemic to Southeast Asia, Northern Australia and temperate regions that border the equator [1, 4]. While melioid- osis presents a significant health threat to people indigenous to these geographical domains, the clinical manifestations of this disease are rarely observed in the Western Hemisphere [4, 5]. The organism may be routinely isolated from environmental niches such as stagnant waters, moist soils and rice paddies [6–8]. Acquisition of melioidosis is thought to occur via the inoculation of damaged surface tissues with the contaminated soils or water, or by the inhalation and aspiration of infectious dust particles [4, 8, 9]. Melioidosis manifests itself as acute, sub-acute and chronic illnesses [4]. The acute disease is rapidly fatal * Corresponding author. without treatment, and even chemotherapeutic in- tervention in these cases offers a poor prognosis for the patient [4, 10, 11]. Sub-acute melioidosis is best described as a prolonged febrile illness characterized by multi-organ involvement, systemic abscess for- mation and bacteraemia. This too is fatal if left untreated [11]. Chronic melioidosis is thought to be the most common presentation of this disease [10]. Diagnosis is most often achieved by post-mortem examination of infected tissues, or when clinical indications present themselves upon activation of the disease by a traumatic event. Accumulating evidence suggests that physiological abnormalities such as diabetes mellitus and renal disease may predispose a host to Burkholderia pseudomallei infections [1, 12, 13]. Our laboratory has initiated studies to define the pathogenesis of disease due to Burkholderia pseudomallei. Although several putative virulence https://doi.org/10.1017/S095026889600739X Published online by Cambridge University Press
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