Efficacy of Bisphosphonate-Conjugated Sitafloxacin in a Murine Model of S. aureus Osteomyelitis: Evidence of “Target & Release” Kinetics and Killing of Bacteria Within Canaliculi
S. aureus infection of bone is difficult to eradicate due to its ability to colonize the osteocyte-lacuno-canalicular network (OLCN), rendering it resistant to standard-of-care (SOC) antibiotics. To overcome this, we proposed two bone-targeted bisphosphonate-conjugated antibiotics (BCA): bisphosphon...
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Frontiers Media S.A.
2022-06-01
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| Series: | Frontiers in Cellular and Infection Microbiology |
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| Online Access: | https://www.frontiersin.org/articles/10.3389/fcimb.2022.910970/full |
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| author | Youliang Ren Youliang Ren Thomas Xue Joshua Rainbolt Karen L. de Mesy Bentley Karen L. de Mesy Bentley Karen L. de Mesy Bentley Karen L. de Mesy Bentley Chad A. Galloway Chad A. Galloway Yuting Liu Philip Cherian Jeffrey Neighbors Jeffrey Neighbors Marloes I. Hofstee Frank H. Ebetino Frank H. Ebetino Thomas Fintan Moriarty Shuting Sun Edward M. Schwarz Edward M. Schwarz Chao Xie Chao Xie |
| author_facet | Youliang Ren Youliang Ren Thomas Xue Joshua Rainbolt Karen L. de Mesy Bentley Karen L. de Mesy Bentley Karen L. de Mesy Bentley Karen L. de Mesy Bentley Chad A. Galloway Chad A. Galloway Yuting Liu Philip Cherian Jeffrey Neighbors Jeffrey Neighbors Marloes I. Hofstee Frank H. Ebetino Frank H. Ebetino Thomas Fintan Moriarty Shuting Sun Edward M. Schwarz Edward M. Schwarz Chao Xie Chao Xie |
| author_sort | Youliang Ren |
| collection | DOAJ |
| description | S. aureus infection of bone is difficult to eradicate due to its ability to colonize the osteocyte-lacuno-canalicular network (OLCN), rendering it resistant to standard-of-care (SOC) antibiotics. To overcome this, we proposed two bone-targeted bisphosphonate-conjugated antibiotics (BCA): bisphosphonate-conjugated sitafloxacin (BCS) and hydroxybisphosphonate-conjugate sitafloxacin (HBCS). Initial studies demonstrated that the BCA kills S. aureus in vitro. Here we demonstrate the in vivo efficacy of BCS and HBCS versus bisphosphonate, sitafloxacin, and vancomycin in mice with implant-associated osteomyelitis. Longitudinal bioluminescent imaging (BLI) confirmed the hypothesized “target and release”-type kinetics of BCS and HBCS. Micro-CT of the infected tibiae demonstrated that HBCS significantly inhibited peri-implant osteolysis versus placebo and free sitafloxacin (p < 0.05), which was not seen with the corresponding non-antibiotic-conjugated bisphosphonate control. TRAP-stained histology confirmed that HBCS significantly reduced peri-implant osteoclast numbers versus placebo and free sitafloxacin controls (p < 0.05). To confirm S. aureus killing, we compared the morphology of S. aureus autolysis within in vitro biofilm and infected tibiae via transmission electron microscopy (TEM). Live bacteria in vitro and in vivo presented as dense cocci ~1 μm in diameter. In vitro evidence of autolysis presented remnant cell walls of dead bacteria or “ghosts” and degenerating (non-dense) bacteria. These features of autolyzed bacteria were also present among the colonizing S. aureus within OLCN of infected tibiae from placebo-, vancomycin-, and sitafloxacin-treated mice, similar to placebo. However, most of the bacteria within OLCN of infected tibiae from BCA-treated mice were less dense and contained small vacuoles and holes >100 nm. Histomorphometry of the bacteria within the OLCN demonstrated that BCA significantly increased their diameter versus placebo and free antibiotic controls (p < 0.05). As these abnormal features are consistent with antibiotic-induced vacuolization, bacterial swelling, and necrotic phenotype, we interpret these findings to be the initial evidence of BCA-induced killing of S. aureus within the OLCN of infected bone. Collectively, these results support the bone targeting strategy of BCA to overcome the biodistribution limits of SOC antibiotics and warrant future studies to confirm the novel TEM phenotypes of bacteria within OLCN of S. aureus-infected bone of animals treated with BCS and HBCS. |
| first_indexed | 2024-12-12T08:40:03Z |
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| institution | Directory Open Access Journal |
| issn | 2235-2988 |
| language | English |
| last_indexed | 2024-12-12T08:40:03Z |
| publishDate | 2022-06-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Cellular and Infection Microbiology |
| spelling | doaj.art-bce85e9c2bad40a79c4e87db39e8c0b82022-12-22T00:30:49ZengFrontiers Media S.A.Frontiers in Cellular and Infection Microbiology2235-29882022-06-011210.3389/fcimb.2022.910970910970Efficacy of Bisphosphonate-Conjugated Sitafloxacin in a Murine Model of S. aureus Osteomyelitis: Evidence of “Target & Release” Kinetics and Killing of Bacteria Within CanaliculiYouliang Ren0Youliang Ren1Thomas Xue2Joshua Rainbolt3Karen L. de Mesy Bentley4Karen L. de Mesy Bentley5Karen L. de Mesy Bentley6Karen L. de Mesy Bentley7Chad A. Galloway8Chad A. Galloway9Yuting Liu10Philip Cherian11Jeffrey Neighbors12Jeffrey Neighbors13Marloes I. Hofstee14Frank H. Ebetino15Frank H. Ebetino16Thomas Fintan Moriarty17Shuting Sun18Edward M. Schwarz19Edward M. Schwarz20Chao Xie21Chao Xie22Center for Musculoskeletal Research, University of Rochester Medical Center, Rochester, NY, United StatesDepartment of Orthopaedics and Rehabilitation, University of Rochester Medical Center, Rochester, NY, United StatesCenter for Musculoskeletal Research, University of Rochester Medical Center, Rochester, NY, United StatesCenter for Musculoskeletal Research, University of Rochester Medical Center, Rochester, NY, United StatesCenter for Musculoskeletal Research, University of Rochester Medical Center, Rochester, NY, United StatesDepartment of Orthopaedics and Rehabilitation, University of Rochester Medical Center, Rochester, NY, United StatesDepartment of Pathology, University of Rochester Medical Center, Rochester, NY, United StatesCenter for Advanced Research Technologies, University of Rochester Medical Center, Rochester, NY, United StatesDepartment of Pathology, University of Rochester Medical Center, Rochester, NY, United StatesCenter for Advanced Research Technologies, University of Rochester Medical Center, Rochester, NY, United StatesCenter for Musculoskeletal Research, University of Rochester Medical Center, Rochester, NY, United StatesBioVinc LLC, Pasadena, CA, United StatesBioVinc LLC, Pasadena, CA, United StatesDepartment of Pharmacology, Pennsylvania State University, Hershey, PA, United StatesAO Research Institute Davos, Davos Platz, SwitzerlandBioVinc LLC, Pasadena, CA, United StatesDepartment of Chemistry, University of Rochester, Rochester, NY, United StatesAO Research Institute Davos, Davos Platz, SwitzerlandBioVinc LLC, Pasadena, CA, United StatesCenter for Musculoskeletal Research, University of Rochester Medical Center, Rochester, NY, United StatesDepartment of Orthopaedics and Rehabilitation, University of Rochester Medical Center, Rochester, NY, United StatesCenter for Musculoskeletal Research, University of Rochester Medical Center, Rochester, NY, United StatesDepartment of Orthopaedics and Rehabilitation, University of Rochester Medical Center, Rochester, NY, United StatesS. aureus infection of bone is difficult to eradicate due to its ability to colonize the osteocyte-lacuno-canalicular network (OLCN), rendering it resistant to standard-of-care (SOC) antibiotics. To overcome this, we proposed two bone-targeted bisphosphonate-conjugated antibiotics (BCA): bisphosphonate-conjugated sitafloxacin (BCS) and hydroxybisphosphonate-conjugate sitafloxacin (HBCS). Initial studies demonstrated that the BCA kills S. aureus in vitro. Here we demonstrate the in vivo efficacy of BCS and HBCS versus bisphosphonate, sitafloxacin, and vancomycin in mice with implant-associated osteomyelitis. Longitudinal bioluminescent imaging (BLI) confirmed the hypothesized “target and release”-type kinetics of BCS and HBCS. Micro-CT of the infected tibiae demonstrated that HBCS significantly inhibited peri-implant osteolysis versus placebo and free sitafloxacin (p < 0.05), which was not seen with the corresponding non-antibiotic-conjugated bisphosphonate control. TRAP-stained histology confirmed that HBCS significantly reduced peri-implant osteoclast numbers versus placebo and free sitafloxacin controls (p < 0.05). To confirm S. aureus killing, we compared the morphology of S. aureus autolysis within in vitro biofilm and infected tibiae via transmission electron microscopy (TEM). Live bacteria in vitro and in vivo presented as dense cocci ~1 μm in diameter. In vitro evidence of autolysis presented remnant cell walls of dead bacteria or “ghosts” and degenerating (non-dense) bacteria. These features of autolyzed bacteria were also present among the colonizing S. aureus within OLCN of infected tibiae from placebo-, vancomycin-, and sitafloxacin-treated mice, similar to placebo. However, most of the bacteria within OLCN of infected tibiae from BCA-treated mice were less dense and contained small vacuoles and holes >100 nm. Histomorphometry of the bacteria within the OLCN demonstrated that BCA significantly increased their diameter versus placebo and free antibiotic controls (p < 0.05). As these abnormal features are consistent with antibiotic-induced vacuolization, bacterial swelling, and necrotic phenotype, we interpret these findings to be the initial evidence of BCA-induced killing of S. aureus within the OLCN of infected bone. Collectively, these results support the bone targeting strategy of BCA to overcome the biodistribution limits of SOC antibiotics and warrant future studies to confirm the novel TEM phenotypes of bacteria within OLCN of S. aureus-infected bone of animals treated with BCS and HBCS.https://www.frontiersin.org/articles/10.3389/fcimb.2022.910970/fullosteomyelitisStaphylococcus aureustransmission electron microscopyantibioticbisphosphonate |
| spellingShingle | Youliang Ren Youliang Ren Thomas Xue Joshua Rainbolt Karen L. de Mesy Bentley Karen L. de Mesy Bentley Karen L. de Mesy Bentley Karen L. de Mesy Bentley Chad A. Galloway Chad A. Galloway Yuting Liu Philip Cherian Jeffrey Neighbors Jeffrey Neighbors Marloes I. Hofstee Frank H. Ebetino Frank H. Ebetino Thomas Fintan Moriarty Shuting Sun Edward M. Schwarz Edward M. Schwarz Chao Xie Chao Xie Efficacy of Bisphosphonate-Conjugated Sitafloxacin in a Murine Model of S. aureus Osteomyelitis: Evidence of “Target & Release” Kinetics and Killing of Bacteria Within Canaliculi Frontiers in Cellular and Infection Microbiology osteomyelitis Staphylococcus aureus transmission electron microscopy antibiotic bisphosphonate |
| title | Efficacy of Bisphosphonate-Conjugated Sitafloxacin in a Murine Model of S. aureus Osteomyelitis: Evidence of “Target & Release” Kinetics and Killing of Bacteria Within Canaliculi |
| title_full | Efficacy of Bisphosphonate-Conjugated Sitafloxacin in a Murine Model of S. aureus Osteomyelitis: Evidence of “Target & Release” Kinetics and Killing of Bacteria Within Canaliculi |
| title_fullStr | Efficacy of Bisphosphonate-Conjugated Sitafloxacin in a Murine Model of S. aureus Osteomyelitis: Evidence of “Target & Release” Kinetics and Killing of Bacteria Within Canaliculi |
| title_full_unstemmed | Efficacy of Bisphosphonate-Conjugated Sitafloxacin in a Murine Model of S. aureus Osteomyelitis: Evidence of “Target & Release” Kinetics and Killing of Bacteria Within Canaliculi |
| title_short | Efficacy of Bisphosphonate-Conjugated Sitafloxacin in a Murine Model of S. aureus Osteomyelitis: Evidence of “Target & Release” Kinetics and Killing of Bacteria Within Canaliculi |
| title_sort | efficacy of bisphosphonate conjugated sitafloxacin in a murine model of s aureus osteomyelitis evidence of target release kinetics and killing of bacteria within canaliculi |
| topic | osteomyelitis Staphylococcus aureus transmission electron microscopy antibiotic bisphosphonate |
| url | https://www.frontiersin.org/articles/10.3389/fcimb.2022.910970/full |
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