Burkholderia pseudomallei (Bp) and Burkholderia mallei (Bm) are Tier-1 Select Agents that cause melioidosis and glanders, respectively. These are highly lethal human infections with limited therapeutic options. Intercellular spread is a hallmark of Burkholderia pathogenesis, and its prominent ties to virulence make it an attractive therapeutic target. We developed a high-throughput cell-based phenotypic assay and screened ∼220,000 small molecules for their ability to disrupt intercellular spread by Burkholderia thailandensis, a closely related BSL-2 surrogate. We identified 268 hits, and cross-species validation found 32 hits that also disrupt intercellular spread by Bp and/or Bm Among these were a fluoroquinolone analog, which we named burkfloxacin (BFX), which potently inhibits growth of intracellular Burkholderia, and flucytosine (5-FC), an FDA-approved antifungal drug. We found that 5-FC blocks the intracellular life cycle at the point of type VI secretion system 5 (T6SS-5)-mediated cell-cell spread. Bacterial conversion of 5-FC to 5-fluorouracil and subsequently to fluorouridine monophosphate is required for potent and selective activity against intracellular Burkholderia In a murine model of fulminant respiratory melioidosis, treatment with BFX or 5-FC was significantly more effective than ceftazidime, the current antibiotic of choice, for improving survival and decreasing bacterial counts in major organs. Our results demonstrate the utility of cell-based phenotypic screening for Select Agent drug discovery and warrant the advancement of BFX and 5-FC as candidate therapeutics for melioidosis in humans

An in situ high-throughput screen identifies inhibitors of intracellular Burkholderia pseudomallei with therapeutic efficacy / Bulterys, Pl; Toesca, Ij; Norris, Mh; Maloy, Jp; Fitz-Gibbon ST, ; France, B; Toffig, B; Morselli, M; Somprasong, N; Pellegrini M, ; Schweizer, Hp; Tuanyok, A; Damoiseaux, R; French CT, ; Miller, Jf. - In: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA. - ISSN 1091-6490. - (2019). [10.1073/pnas.1906388116]

An in situ high-throughput screen identifies inhibitors of intracellular Burkholderia pseudomallei with therapeutic efficacy

Morselli M;
2019

Abstract

Burkholderia pseudomallei (Bp) and Burkholderia mallei (Bm) are Tier-1 Select Agents that cause melioidosis and glanders, respectively. These are highly lethal human infections with limited therapeutic options. Intercellular spread is a hallmark of Burkholderia pathogenesis, and its prominent ties to virulence make it an attractive therapeutic target. We developed a high-throughput cell-based phenotypic assay and screened ∼220,000 small molecules for their ability to disrupt intercellular spread by Burkholderia thailandensis, a closely related BSL-2 surrogate. We identified 268 hits, and cross-species validation found 32 hits that also disrupt intercellular spread by Bp and/or Bm Among these were a fluoroquinolone analog, which we named burkfloxacin (BFX), which potently inhibits growth of intracellular Burkholderia, and flucytosine (5-FC), an FDA-approved antifungal drug. We found that 5-FC blocks the intracellular life cycle at the point of type VI secretion system 5 (T6SS-5)-mediated cell-cell spread. Bacterial conversion of 5-FC to 5-fluorouracil and subsequently to fluorouridine monophosphate is required for potent and selective activity against intracellular Burkholderia In a murine model of fulminant respiratory melioidosis, treatment with BFX or 5-FC was significantly more effective than ceftazidime, the current antibiotic of choice, for improving survival and decreasing bacterial counts in major organs. Our results demonstrate the utility of cell-based phenotypic screening for Select Agent drug discovery and warrant the advancement of BFX and 5-FC as candidate therapeutics for melioidosis in humans
An in situ high-throughput screen identifies inhibitors of intracellular Burkholderia pseudomallei with therapeutic efficacy / Bulterys, Pl; Toesca, Ij; Norris, Mh; Maloy, Jp; Fitz-Gibbon ST, ; France, B; Toffig, B; Morselli, M; Somprasong, N; Pellegrini M, ; Schweizer, Hp; Tuanyok, A; Damoiseaux, R; French CT, ; Miller, Jf. - In: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA. - ISSN 1091-6490. - (2019). [10.1073/pnas.1906388116]
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11381/2901241
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 9
  • ???jsp.display-item.citation.isi??? 8
social impact