LSU Veterinary School researcher has two articles published in prestigious journal, Pathogens

Dr. Juan Martinez working in his lab.

For Immediate Release: March 31, 2021

BATON ROUGE, LA—The LSU School of Veterinary Medicine is pleased to report the publication of two research articles in the journal Pathogens from the laboratory of Juan J. Martinez, Ph.D., professor in Pathobiological Sciences and a member of the Vector-Borne Disease Laboratories at the LSU SVM. Pathogens is an international, peer-reviewed, open-access journal of pathogens and pathogen-host interactions published monthly online.

The first article is a review article entitled “Modulation of Host Lipid Pathways by Pathogenic Intracellular Bacteria” authored by Paige E. Allen, a fourth-year graduate student, and Dr. Martinez. This comprehensive review focuses on the current knowledge regarding how facultative and obligate intracellular bacteria manipulate the infected host cell to provide intracellular niches that are hospitable for growth and survival in a variety of infected mammalian cell types. Allen describes and outlines mechanisms utilized by vacuolar and non-vacuolar bacteria to access certain classes of host-derived lipids and fatty acids for structural and energy requirements involved in growth. “This important review provides a compare/contrast analysis of what is currently known regarding how certain disease-causing bacteria manipulate the infected host cell to provide nutrients essential for growth. The more we learn about these processes, the better we can potentially target them for therapeutic intervention,” said Dr. Martinez.

The second article is a work principally authored by M. Nathan Kristof, a former undergraduate research student in the Martinez Lab, and is entitled “Significant Growth by Rickettsia Species within Macrophage-Like Cells Is a Phenotype Correlated with the Ability to Cause Disease in Mammals.” The research group had previously demonstrated that Rickettsia conorii , the bacteria responsible for Mediterranean spotted fever (MSF), is capable of growing efficiently in mammalian cells called monocytes and macrophages that are cells of the immune system typically used to get rid of the infecting bacteria. Kristof, along with current graduate students Paige E. Allen and Lane D. Yutzy, a former undergraduate student and current SVM student Brandon Thibodaux (Class of 2021), and collaborator Christopher Paddock, Ph.D. from the Centers for Disease Control in Atlanta, extended these observations. In this work, they demonstrate that several other pathogenic species from around the world including R. rickettsii (the agent of Rocky Mountain spotted fever), R. parkeri (agent of spotted fever in North America), R. africae (agent of African tick-bite fever) and R. akari (agent of rickettsialpox) also could grow within macrophage-like cells. In contrast, another species not associated with human or animal disease, R. bellii, and an attenuated, avirulent strain of R. rickettsii (strain Iowa), did not significantly growth within macrophages. “The significance of these findings is that one simply cannot compare the genomes of known, bona fide pathogenic and non-pathogenic Rickettsia species to predict whether or not a species will be capable of causing disease in humans and companion animals such as dogs,” said Dr. Martinez. “The analysis of growth in macrophages for example may be a better indicator of whether previously isolated strains and newly emerging Rickettsia species have the capacity to cause disease. Hopefully this work will expand research into the mechanisms by which pathogenic species are capable of infecting cells that are normally geared to destroy the bacteria, set up shop and disseminate in the infected animal.” These published studies were in part funded by an award (R01 AI072606) from the National Institutes of Health (NIH), National Institute of Allergy and Infectious Diseases (NIAID) to Dr. Martinez.

About the LSU School of Veterinary Medicine

The LSU School of Veterinary Medicine is one of only 32 veterinary schools in the U.S. and the only one in Louisiana. The LSU SVM is dedicated to improving the lives of people and animals through education, research, and service. We teach. We heal. We discover. We protect.

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