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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 29 years of experience in Ultrastructural Pathology and is considered an expert in both diagnostic and research electron microscopy. She 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 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 is the Director of the Medical Center's Electron Microscope Shared Resource Facility.


Ms. (de Mesy) Bentley is currently, the Director of the Electron Microscopy Shared Resource and has 29 years of teaching and 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.

In 2011, Ms. Bentley was recruited by Dr. Edward Schwarz, the Director of the Center for Musculoskeletal Research in Orthopaedics, to investigate and analyze a mouse model of Staphylococcus aureus (MRSA and MSSA strains) infected implants and biofilm formation using scanning electron microscopy (SEM) which resulted in two Orthopaedic Research Society journal covers. In 2014, she initiated transmission electron microscopy (TEM) studies on the infected bone which had surrounded the biofilm laden implants. Ms. Bentley's high magnification TEM study led to the discovery of S. aureus' deforming into submicron rod-shaped bacteria to colonize the ostetocytic-lacunar canaliculi network of bone. This was the first evidence of S. aureus, a round non-motile 1-1.5 micron sized bacteria, becoming rod-shaped to enter (using asymmetric binary fission) the narrow confines of (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 an electron micrograph from her study was also chosen for a book cover, Osteoimmunology, 2nd Ed, 2016.

She has also authored and co-authored over 50 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

Nishitani K, Ishikawa M, Morita Y, Yokogawa N, Xie C, de Mesy Bentley KL, Ito H, Kates SL, Daiss JL, Schwarz EM. "IsdB antibody-mediated sepsis following S. aureus surgical site infection." JCI insight.. 2020 Oct 2; 5(19)Epub 2020 Oct 02.

Tomizawa T, Ishikawa M, Bello-Irizarry SN, de Mesy Bentley KL, Ito H, Kates SL, Daiss JL, Beck C, Matsuda S, Schwarz EM, Nishitani K. "Biofilm producing Staphylococcus epidermidis (RP62A strain) inhibits osseous integration without osteolysis and histopathology in a murine septic implant model." Journal of orthopaedic research : official publication of the Orthopaedic Research Society.. 2019 Nov 6; Epub 2019 Nov 06.

Trombetta RP, de Mesy Bentley KL, Schwarz EM, Kate SL, Awad HA. "A murine femoral ostectomy model with hardware exchange to assess antibiotic-impregnated spacers for implant-associated osteomyelitis." European cells & materials. 2019 Jun 27; 37:431-443. Epub 2019 Jun 27.

Books & Chapters

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: 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: 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