Charles E. Benson
School of Veterinary Medicine, University of Pennsylvania
Dr. Charles E. Benson is a Professor of Microbiology and Chief of Clinical Veterinary Microbiology in the Laboratory of Microbiology in the Department of Pathobiology of the School of Veterinary Medicine at the University of Pennsylvania. He has a secondary appointment in the Department of Clinical Studies at New Bolton Center. He received his Bachelor’s degree in Biology from Franklin College in Indiana, a Master’s degree from Miami University in Ohio and a doctoral degree from Wake Forest University. He received post-doctoral training in the School of Medicine of the University of Pennsylvania and was a Scholar in the Medical School Program to Develop Scientists in Medical Research.
Dr Benson began his teaching and research career in the School of Allied Medical Profession of the University and later transferred to the faculty of The School of Veterinary Medicine. His research focuses on the molecular epidemiology and molecular pathogenesis of bacterial intestinal pathogens and has focused primarily on infections caused by Salmonella. Most of the research has been focused on horses and food animals but he has ventured into some small companion animal work. He has published extensively in peer-reviewed journals. Dr. Benson was one of the UP researchers to study “Potomac Horse Fever” and isolated the etiological agent of that disease. He developed the Salmonella Reference Center (SRC) to complement the endeavors of the Pennsylvania Department of Agriculture. The SRC has grown to serve the State-sponsored studies as well as serving many other States and producers throughout the country. He served as the chairman of the Department of Clinical Studies at New Bolton Center from 1989 to 1994. A new addition to the research program is a study to develop non-antibiotic treatments of diseases in food animals. He founded a course Food Safety and Quality Assurance for the fourth year veterinary students in the School five years ago.
Pennsylvania’s food products have been incriminated in a variety of food-associated diseases for many years. Focused efforts to control or retard the spread of pathogens through foods began, in my experience, with the findings that eggs from Pennsylvania were contaminated with salmonellae. The organism is called Salmonella enterica serovar Enteritidis or SE and the NBC laboratories were the first in the country to demonstrate that SE could be isolated from the ovaries of infected hens implying transovarial transmission. This means that eggs containing SE could be laid and sold without any knowledge that the organisms were present. Poultry specialists along the Northeast coast worked to retard the dissemination of SE throughout flocks and subsequently into eggs. These efforts lead a USDA Task Force working with the Pennsylvania Department of Agriculture, poultry producers and academic institutions to develop specific guidelines for the management of flocks. This plan is called PEQAP (the Pennsylvania Egg Quality Assurance Plan) and has been in operation for nearly 10 years. About this same time, the USDA (United States Department of Agriculture) issued guidelines (Hazard Analysis Critical Control Points or HACCP) that were designed to insure contamination of food substances would not occur. The development of a HACCP protocol was assigned to each industry. In addition, President Clinton signed a bill to insure the safety of food from the “farm to the fork”. At NBC, we took the initiative to be more proactive and established the Salmonella Reference Center (SRC), to provide more immediate answers to identification and epidemiology questions. We then moved into a general surveillance mode to screen animals not yet implicated in a food-associated transmission case. We wanted to solve a problem before it occurred!
New strains of Salmonella are often seen in Europe and the UK before arriving in the US. One such strain (called DT 104) carries a minimum of five (5) drug resistant genes integrated in the genome and appears most frequently associated with cattle and swine. This strain presents a serious impact on the treatment of a human infection caused by this strain because of the wide spread of resistance to antibiotics. Herds, identified through referral of strange cases or unusual mortalities are rapidly screened using SRC specifically developed techniques for isolation and identification. Our veterinarian colleagues provide directions to the producers to change management methods. We also discovered another highly pathogenic strain of Salmonella that also carries multi-antibiotic resistant genes on a plasmid. Gradually headway is being made to search for these pathogens before they enter into the food system using the basic skills of both the veterinarian and the producer. Cost is considerably less, results are quickly observed as calf mortality drops and Pennsylvania food is safer for this proactive rather than reactive approach.
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