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Karen L. Bentley, M.S.

Contact Information

Phone Numbers

Office: (585) 275-1954

Research Labs

The purpose of the URMC Electron Microscope Research Core Facility is to provide up-to-date and cost-effective support to researchers whose studies involve the use of electron microscopy.

Visit The purpose of the URMC Electron Microscope Research Core Facility is to provide up-to-date and cost-effective support to researchers whose studies involve the use of electron microscopy. Lab Website

Faculty Appointments


Professional Background

Ms.(de Mesy) Bentley has over 35 years of experience in Ultrastructural Pathology and is considered an expert in both diagnostic and research electron microscopy. She previously served as the Associate Director of the Diagnostic Electron Microscope (EM) Laboratory with P. Anthony di Sant'Agnese, M.D., a surgical pathologist, who was the Laboratory Director. Together they developed a month long resident Diagnostic EM rotation which focused on interpretation of tumors, infectious and storage diseases. They also organized 100 Diagnostic EM teaching sets for Pathology residents and other URMC departmental resident trainees. Ms. Bentley has been innovative in the development of EM customized techniques to support both EM based clinical and research projects.

At present, she serves as the Director of the Medical Center's Electron Microscope Resource (EMR) and supports URMC researchers in projects requiring Transmission Electron Microscopy and Scanning Electron Microscopy in the Center for Advanced Research Technologies (CART). In 2020 the EMR acquired a Thermo Fisher Talos 120C Cryo Electron Microscope for structural biology researchers who request imaging of macromolecular structures.


Ms. (de Mesy) Bentley is currently, the Director of the Electron Microscopy Resource (EMR) in the Center for Advanced Research Technologies (CART) and has over 35 years of teaching and Electron Microscopy based diagnostic experience in Ultrastructural Pathology, Immunoelectron Microscopy labeling using gold-tagged secondary antibodies, Hematology, Dental Research, Infectious Agents, Biofilm Formation, Nanoparticle Characterization, Morphometric Analysis and X-ray Dispersive Spectroscopy using both Transmission and Scanning Electron Microscopes.

Ms. Bentley published in the Journal of Orthopaedic Research in 2021, the first 3-dimensional volume reconstruction (cover of journal) of 264 consecutive 60 nm epoxy sections of Stapylococcus aureus invading the Osteocyte-Lacuno Canalicular Network (OLCN). This 3D volume rendering analyzed S. aureus occupation in the OLCN, in that, 70% of the OLCN were invaded by S. aureus, while the remaining 30% non-infected canaliculi appeared to be resistant to infection. This observation has led to the hypothesis that viable osteocytes of the OLCN can respond and resist infection, opening future research directions to explain the paradox of adjacent uninfected canaliculi and life long deep bone infection in patients with chronic osteomyelitis. This work was done in collaboration with Dr. Edward Schwarz, director of the Center for Musculoskeletal Research and Dr. Jonathan Leckenby, an expert in volume reconstruction.

In 2014, Ms. Bentley initiated the first transmission electron microscopy (TEM) studies on S. aureus infected mouse bone (using a bacteria coated stainless steel wire implant) 14 days post- infection. Ms. Bentley's high magnification TEM study resulted in the first ever discovery of S. aureus' deforming into submicron rod-shaped bacteria to colonize the osteocyte-canaliculi of bone. She documented how S. aureus, normally a round non-motile 1-1.5 micron sized bacteria, becomes rod-shaped to enter (using asymmetric binary fission) the submicron (0.4-0.2 micron diameter) canaliculi within live bone. This finding was published in the Journal of Bone and Mineral Research in May, 2017 and in 2016 an electron micrograph from her study was also chosen for a book cover, Osteoimmunology, 2nd Ed.

Ms Bentley has also authored and co-authored over 90 research publications resulting from her years of collaborative TEM and SEM imaging support to researchers here at the University. URMC Researchers who require high magnification imaging support can request a consultation and an estimate of cost prior to starting a research project. This facility provides full wet-lab services for tissue/cells processing, embedding, sectioning and utilizes a Hitachi 7650 TEM/STEM electron microscope with an attached 11 megapixel Gatan digital camera system. It is located in the basement of the Medical School building. A Zeiss Auriga scanning electron microscope housed in Wilmot Hall on the River Campus is used by the laboratory when performing SEM studies.



BS | University of Rochester

MS | Univ Rochester Sch Med/Dent


2017 - 2017
Best Poster Teaser Platform Presentation
Sponsor: Orthopaedic Research Society
Location: San Diego, California

Current Concepts in Ultrastructural Pathology
Sponsor: Ultrapath IV
Location: Ullensvang, Norway

M.S. Anatomy/Pathology

B.S. Cum laude
Location: University of Rochester

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Journal Articles

Mestre H, Verma N, Greene TD, Lin LA, Ladron-de-Guevara A, Sweeney AM, Liu G, Thomas VK, Galloway CA, de Mesy Bentley KL, Nedergaard M, Mehta RI. "Periarteriolar spaces modulate cerebrospinal fluid transport into brain and demonstrate altered morphology in aging and Alzheimer's disease." Nature communications.. 2022 Jul 6; 13(1):3897. Epub 2022 Jul 06.

Masters EA, Ricciardi BF, Bentley KLM, Moriarty TF, Schwarz EM, Muthukrishnan G. "Skeletal infections: microbial pathogenesis, immunity and clinical management." Nature reviews. Microbiology.. 2022 Feb 15; Epub 2022 Feb 15.

Ren Y, Xue T, Rainbolt J, Bentley KLM, Galloway CA, Liu Y, Cherian P, Neighbors J, Hofstee MI, Ebetino FH, Moriarty TF, Sun S, Schwarz EM, Xie C. "Efficacy of Bisphosphonate-Conjugated Sitafloxacin in a Murine Model of Osteomyelitis: Evidence of "Target & Release" Kinetics and Killing of Bacteria Within Canaliculi." Frontiers in cellular and infection microbiology.. 2022 12:910970. Epub 2022 Jun 24.

Books & Chapters

Chapter Title: Implant-Associated Biofilm
Book Title: Principles of Orthopedic Infection Management
Author List: Kohei Nishitani, Karen de Mesy Bentley, John L. Daiss
Edited By: Stephen L. Kates and Olivier Borens
Published By: George Thieme Verlag 2016 in Stuttgart, Germany

Chapter Title: The Role of the Immune System and Bone Cells in Acute and Chronic Osteomyelitis.
Book Title: Osteoimmunology: Interactions of the Immune and Skeletal Systems
Author List: Kohei Nishitani, Sheila N. Bello-Irizarry, Karen L. de Mesy Bentley, John L. Daiss, Edward M. Schwarz:
Edited By: Lorenzo J, Horowitz M, Choi Y, Takayanagi H, Schett G
Published By: Elsevier 2016 in London

Chapter Title: Prostatic and urethral endocrine-paracrine cells in health and disease. An ultrastructural review.
Book Title: Ultrastructure of the Male Urogenital Glands: Prostate, Seminal Vesicles, etc
Author List: Karen L. de Mesy Jensen (now Bentley) and P. Anthony di Sant'Agnese
Edited By: Riva, A; Riva, FT; Motta, P:
Published By: Kluwer Academic Publishers 1994 in Dordrecht