PubMed · 7529862
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T Cherian, P Raghupathy, T J John. 1995-01-28. Plague in India.. https://pubmed.ncbi.nlm.nih.gov/7529862/
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UNLABELLED: Burkholderia pseudomallei (Bp) is a gram-negative bacterium found in soil and surface water. It is also the pathogen that causes melioidosis disease in humans and animals. This study aimed to obtain the whole genome sequence of the endemic strain of Bp in Hainan, using third-generation sequencing (TGS) technology, and elucidate the genome structure, function, and genetic evolution. Additionally, the study aimed to achieve rapid and specific identification of these endemic strains using specific high-sensitivity enzymatic reporter unlocking (SHERLOCK) detection technology, providing a new strategy for the early diagnosis of melioidosis. Utilizing the PacBio platform for TGS technology, we completed whole genome sequencing of 16 Bp strains from Hainan. High-precision and complete genome sequences were obtained through quality control and genome assembly of the sequencing data. Additionally, we established a nucleic acid detection technology platform based on SHERLOCK, which could be completed from nucleic acid extraction to result reading within 1-2 hours, demonstrating good sensitivity and specificity (both are 100%). The lateral chromatography strip method does not require special equipment and holds promise as an immediate screening method for the early diagnosis of melioidosis. IMPORTANCE: Melioidosis is a highly pathogenic infectious disease caused by a gram-negative bacterium of Burkholderia pseudomallei (Bp). The traditional gold standard for diagnosing melioidosis is still isolation and culture from clinical samples. Although this method has high specificity, it has low sensitivity and is time-consuming, which often leads to misdiagnosis or missed diagnosis of melioidosis, affecting subsequent treatment. In this study, recombinase polymerase amplification technology and clustered regularly interspaced short palindromic repeats/Cas13a technology were combined to establish the Specific High-sensitivity Enzymatic Reporter Unlocking detection technology, which can achieve rapid and accurate identification of Bp, providing a new method for the early diagnosis of melioidosis.
BACKGROUND: Burkholderia pseudomallei is a saprophyte in tropical environments and an opportunistic human pathogen. This versatility requires a sensing mechanism that allows the bacterium to respond rapidly to altered environmental conditions. We characterized a two-component signal transduction locus from B. pseudomallei 204, mrgR and mrgS, encoding products with extensive homology with response regulators and histidine protein kinases of Escherichia coli, Bordetella pertussis, and Vibrio cholerae. RESULTS: The locus was present and expressed in a variety of B. pseudomallei human and environmental isolates but was absent from other Burkholderia species, B. cepacia, B. cocovenenans, B. plantarii, B. thailandensis, B. vandii, and B. vietnamiensis. A 2128 bp sequence, including the full response regulator mrgR, but not the sensor kinase mrgS, was present in the B. mallei genome. Restriction fragment length polymorphism downstream from mrgRS showed two distinct groups were present among B. pseudomallei isolates. Our analysis of the open reading frames in this region of the genome revealed that transposase and bacteriophage activity may help explain this variation. MrgR and MrgS proteins were expressed in B. pseudomallei 204 cultured at different pH, salinity and temperatures and the expression was substantially reduced at 25 degrees C compared with 37 degrees C or 42 degrees C but was mostly unaffected by pH or salinity, although at 25 degrees C and 0.15% NaCl a small increase in MrgR expression was observed at pH 5. MrgR was recognized by antibodies in convalescent sera pooled from melioidosis patients. CONCLUSION: The results suggest that mrgRS regulates an adaptive response to temperature that may be essential for pathogenesis, particularly during the initial phases of infection. B. pseudomallei and B. mallei are very closely related species that differ in their capacity to adapt to changing environmental conditions. Modifications in this region of the genome may assist our understanding of the reasons for this difference.
Pseudomonas aeruginosa synthesizes diverse 2-alkyl-4(1H)-quinolones (AHQs), including the signaling molecule 2-heptyl-3-hydroxy-4(1H)-quinolone (PQS), via the pqsABCDE locus. By examining the genome databases, homologs of the pqs genes were identified in other bacteria. However, apart from P. aeruginosa, only Burkholderia pseudomallei and B. thailandensis contained a complete pqsA-E operon (termed hhqA-E). By introducing the B. pseudomallei hhqA and hhqE genes into P. aeruginosa pqsA and pqsE mutants, we show that they are functionally conserved and restore virulence factor and PQS production. B. pseudomallei, B. thailandensis, B. cenocepacia, and P. putida each produced 2-heptyl-4(1H)-quinolone (HHQ), but not PQS. Mutation of hhqA in B. pseudomallei resulted in the loss of AHQ production, altered colony morphology, and enhanced elastase production, which was reduced to parental levels by exogenous HHQ. These data reveal a role for AHQs in bacterial cell-to-cell communication beyond that seen in P. aeruginosa.