Seronegative Bacteremic Melioidosis Caused by
            <i>Burkholderia pseudomallei</i>
            with Ambiguous Biochemical Profile: Clinical Importance of Accurate Identification by 16S rRNA Gene and
            <i>groEL</i>
            Gene Sequencing

Melioidosis, caused by the gram-negative saprophyte Burkholderia pseudomallei, is a disease of public health importance in southeast Asia and northern Australia that is associated with high case-fatality rates in animals and humans. It has the potential for epidemic spread to areas where it is not endemic, and sporadic case reports elsewhere in the world suggest that as-yet-unrecognized foci of infection may exist. Environmental determinants of this infection, apart from a close association with rainfall, are yet to be elucidated. The sequencing of the genome of a strain of B. pseudomallei has recently been completed and will help in the further identification of virulence factors. The presence of specific risk factors for infection, such as diabetes, suggests that functional neutrophil defects are important in the pathogenesis of melioidosis; other studies have defined virulence factors (including a type III secretion system) that allow evasion of killing mechanisms by phagocytes. There is a possible role for cell-mediated immunity, but repeated environmental exposure does not elicit protective humoral or cellular immunity. A vaccine is under development, but economic constraints may make vaccination an unrealistic option for many regions of endemicity. Disease manifestations are protean, and no inexpensive, practical, and accurate rapid diagnostic tests are commercially available; diagnosis relies on culture of the organism. Despite the introduction of ceftazidime- and carbapenem-based intravenous treatments, melioidosis is still associated with a significant mortality attributable to severe sepsis and its complications. A long course of oral eradication therapy is required to prevent relapse. Studies exploring the role of preventative measures, earlier clinical identification, and better management of severe sepsis are required to reduce the burden of this disease

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“…Sequencing of the groEL gene may also be useful but may not reliably differentiate B. mallei from B. pseudomallei (484,485).…”

Section: Diagnosis and Management Of Melioidosis Diagnosismentioning

confidence: 99%

Melioidosis: Epidemiology, Pathophysiology, and Management

2005

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“…Accurate identification of B. pseudomallei is important, since treatment of melioidosis requires prolonged antibiotics to prevent relapse (9). Although B. pseudomallei differs greatly from other Burkholderia species in pathogenicity and epidemiology, identification of B. pseudomallei is often difficult, as phenotypic tests and even 16S rRNA gene sequencing may not offer adequate discrimination from related species, such as B. thailandensis and B. cepacia complex (BCC) (3)(4)(5)(6)8).…”

mentioning

confidence: 99%

Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry for Rapid Identification of Burkholderia pseudomallei: Importance of Expanding Databases with Pathogens Endemic to Different Localities

et al. 2012

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“…Although coinfection by the B. cepacia complex and B. pseudomallei in cystic fibrosis patients has been reported (31), commercial systems often fail to distinguish between the two organisms (14,24,43). Since the treatment of B. pseudomallei infection requires a prolonged course of antibiotics (46), this can directly affect management, as inadequate treatment is associated with a high rate of relapse (12). Moreover, misidentification is a significant health risk to the microbiological laboratory personnel (33), as laboratory-acquired melioidosis following exposure from antimicrobial susceptibility testing on a misidentified B. cepacia complex isolate has been reported (35).…”

mentioning

confidence: 99%

Novel Pan-Genomic Analysis Approach in Target Selection for Multiplex PCR Identification and Detection of Burkholderia pseudomallei, Burkholderia thailandensis, and Burkholderia cepacia Complex Species: a Proof-of-Concept Study

Lau

Martelli

et al. 2011

J Clin Microbiol

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Burkholderia pseudomallei, Burkholderia thailandensis, and the Burkholderia cepacia complex differ greatly in pathogenicity and epidemiology. Yet, they are occasionally misidentified by biochemical profiling, and even 16S rRNA gene sequencing may not offer adequate discrimination between certain species groups. Using the 23 B. pseudomallei, four B. thailandensis, and 16 B. cepacia complex genome sequences available, we identified gene targets specific to each of them (a Tat domain protein, a 70-kDa protein, and a 12-kDa protein for B. pseudomallei, B. thailandensis, and the B. cepacia complex, respectively), with an in-house developed algorithm. Using these targets, we designed a robust multiplex PCR assay useful for their identification and detection from soil and simulated sputum samples. For all 43 B. pseudomallei, seven B. thailandensis, and 20 B. cepacia complex (B. multivorans, n ‫؍‬ 6; B. cenocepacia, n ‫؍‬ 3; B. cepacia, n ‫؍‬ 4; B. arboris, n ‫؍‬ 2; B. contaminans, B. anthina, and B. pyrrocinia, n ‫؍‬ 1 each; other unnamed members, n ‫؍‬ 2) isolates, the assay produced specific products of predicted size without false positives or negatives. Of the 60 soil samples screened, 19 (31.6%) and 29 (48.3%) were positive for B. pseudomallei and the B. cepacia complex, respectively, and in four (6.7%) soil samples, the organisms were codetected. DNA sequencing confirmed that all PCR products originated from their targeted loci. This novel pan-genomic analysis approach in target selection is simple, computationally efficient, and potentially applicable to any species that harbors species-specific genes. A multiplex PCR assay for rapid and accurate identification and detection of B. pseudomallei, B. thailandensis, and the B. cepacia complex was developed and verified.

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Seronegative Bacteremic Melioidosis Caused by Burkholderia pseudomallei with Ambiguous Biochemical Profile: Clinical Importance of Accurate Identification by 16S rRNA Gene and groEL Gene Sequencing

Cited by 23 publications

References 19 publications

Melioidosis: Epidemiology, Pathophysiology, and Management

Melioidosis: Epidemiology, Pathophysiology, and Management

Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry for Rapid Identification of Burkholderia pseudomallei: Importance of Expanding Databases with Pathogens Endemic to Different Localities

Novel Pan-Genomic Analysis Approach in Target Selection for Multiplex PCR Identification and Detection of Burkholderia pseudomallei, Burkholderia thailandensis, and Burkholderia cepacia Complex Species: a Proof-of-Concept Study

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