James M.  Musser, MD, PhD

James M. Musser, MD, PhD

Houston Methodist

Chair, Department of Pathology & Genomic Medicine

Expertise: Group A streptococcus Group A streptococcus Mycobacterium TuberculosisMycobacterium Tuberculosis


Following postdoctoral research at the Institute of Molecular Evolutionary Genetics, Pennsylvania State University, and residency training in laboratory medicine at the Hospital of the University of Pennsylvania, Dr. Musser joined the pathology department, Baylor College of Medicine in Houston, Texas. He advanced through the academic ranks from 1991 to 1998, when he was promoted to professor. Dr. Musser served as the chief of the Laboratory of Human Bacterial Pathogenesis at the National Institute of Allergy and Infectious Diseases from 1999-2003. He joined Houston Methodist Research Institute in 2005 and served as co-director and executive vice president until 2010. In addition to holding the Fondren Presidential Distinguished Chair, Dr. Musser is also the chair of the Department of Pathology and Genomic Medicine and the director of the Center for Molecular and Translational Human Infectious Diseases Research. His research focuses on the molecular basis of host-pathogen interactions in group A Streptococcus and Mycobacterium tuberculosis. He serves on several editorial boards, has received many national and international honors and awards, and has published more than 300 research articles and book chapters.

Description of Research


The goal of Dr. Musser's research is to advance our understanding of pathogen-host interactions, broadly defined. His laboratory uses a highly integrated interdisciplinary research strategy that employs state-of-the-art techniques such as genome sequencing, expression microarray analysis, molecular population genetic analysis, relevant in vivo model systems, and analysis of host factors to gain new information about the molecular basis of infections caused by the human pathogenic bacterium group A Streptococcus (GAS) and Mycobacterium tuberculosis. All of the laboratory's work involves extensive collaboration with local, national, and international investigators with diverse areas of expertise.

One project is to identify key vaccine candidates against group A Streptococcus. This work is performed in collaboration with investigators in the private sector. GAS causes >700 million cases of human disease each year globally, yet no licensed vaccine is available, despite decades of study. Dr. Musser's goal is to use a multi-modality experimental strategy involving molecular dissection of the pathogen and host immunologic response, in vivo disease models, and analysis of clinical material to identify one or more protein antigens that protect humans against GAS pharyngitis and invasive disease.

A second project is designed to elucidate the molecular genetic events contributing to epidemics of GAS infection. This work is done in collaboration with several groups of investigators. The team uses a comprehensive, population-based sample of serotype M3 strains recovered over 16 years from patients with invasive infections as a model system. The project involves extensive (“deep”) comparative genome resequencing and genetic polymorphisms analysis using GAS strains from patients with well-defined clinical phenotype. The goal of this line of research is to understand precise temporal and geographic patterns of strain spread. In addition, the team seeks to define genetic polymorphisms and virulence regulatory circuits in the pathogen that influence clinical phenotype. Recent work has identified a novel virulence circuit involved in the pathogenesis of necrotizing fasciitis, also known as the “flesh-eating” disease. The research also has vaccine and public health implications.

Finally, Dr. Musser has a longstanding interest in the genetic epidemiology of human susceptibility to tuberculosis disease. Using a cohort of extensively defined human tuberculosis patients and controls, his team seeks to define human genetic factors that help to determine why some individuals get tuberculosis disease whereas others who have been exposed to the organism do not. A combination of single nucleotide polymorphism analysis and deep candidate gene resequencing is used, as well as other contemporary human genetic analysis methods.


Areas Of Expertise

Mycobacterium tuberculosis Group A Streptococcus
Education & Training

Residency, University of Pennsylvania Health System
MD, University of Rochester

No Research/Citations

Genome sequencing reveals widespread COVID-19 infection in white-tailed deer

Houston Methodist’s SARS-CoV-2 genome sequencing team has partnered on a study led by Penn State that revealed 80% of white-tailed deer sampled across Iowa at the height of the 2020-2021 deer-hunting season tested positive for the SARS-CoV-2 virus. Analysis of the virus genome sequences revealed infections were likely the result of multiple human-to-deer transmission “spillover” events followed by deer-to-deer transmission from April 2020 through January 2021.
09-Nov-2021 08:55:11 AM EST

Houston Methodist study reveals COVID-19 UK variant cases doubling weekly in Houston

Houston Methodist infectious disease pathologists have discovered new COVID-19 cases caused by the SARS-CoV-2 UK B.1.1.7 variant are doubling weekly. By mid-March the number increased sharply to 648 cases from 305 just a week earlier. The findings come from the latest batch of 8,857 virus genomes sequenced from patients with positive COVID-19 tests in the first two months of 2021, representing 94% of Houston Methodist cases.
31-Mar-2021 06:00:52 PM EDT

Houston Methodist finds multiple cases of significant coronavirus mutations, including Brazil strain

Houston Methodist has sequenced more than 20,000 of Houston’s coronavirus genomes since the start of the pandemic and leads the SARS-CoV-2 genome sequencing efforts in the U.S. In the most recent batches of genomes, the U.K., South Africa, Brazil, California and New York variants were detected.
02-Mar-2021 03:05:43 PM EST

60-day follow-up of 300+ COVID-19 patients demonstrates convalescent plasma therapy is safe and effective

A follow-up Houston Methodist study of 351 COVID-19 patients treated with convalescent plasma therapy concludes those patients receiving convalescent plasma with a very high antibody content – or high titer – within 72 hours of hospitalization were significantly more likely to survive SARS-CoV-2 coronavirus infection. The results confirm and extend scientific evidence from an earlier interim study and show transfusion of high-titer convalescent plasma has maximum beneficial effect if given within 44 hours of hospitalization.
06-Oct-2020 03:05:36 PM EDT

Preliminary study of 300+ COVID-19 patients suggests convalescent plasma therapy effective

A preliminary analysis of an ongoing study of more than 300 COVID-19 patients treated with convalescent plasma therapy at Houston Methodist suggests the treatment is safe and effective. The results, published in The American Journal of Pathology, represent one of the first peer-reviewed publications in the country assessing efficacy of convalescent plasma and offer valuable scientific evidence that transfusing critically ill COVID-19 patients with high antibody plasma early in their illness reduced the mortality rate.
12-Aug-2020 06:30:44 PM EDT

Study finds COVID-19 convalescent plasma therapy safe, with 76% patients improving

The first convalescent plasma transfusion trial results from Houston Methodist have been published. Of the study’s 25 patients, 19 have improved and 11 discharged. With no adverse side effects caused by the therapy, the study concluded convalescent plasma is a safe treatment option for patients with severe COVID-19. This is the first peer-reviewed publication in the U.S. of convalescent plasma therapy results for COVID-19.
07-Jun-2020 10:05:27 PM EDT

Study finds COVID plasma therapy safe, with 76% patients improving

The first convalescent plasma transfusion trial results from Houston Methodist have been released. Of the 25 patients in the study, 19 have improved and 11 have been discharged. With no adverse side effects caused by the therapy, the study concluded that convalescent plasma is a safe treatment option for patients with severe COVID-19. This is the largest cohort assessed for outcomes related to convalescent plasma therapy for COVID-19.
13-May-2020 12:05:21 PM EDT

Houston Methodist researchers find telling clues in virus genes from COVID-19 patients

Houston Methodist released gene sequencing results from the first strains of the virus causing COVID-19 disease in Houston. Results reveal multiple introductions of SARS-CoV-2 into Houston followed by rapid community spread. No evidence was found of mutations making any strains of the virus more severe. Pathologists analyzed genomes of 320 SARS-CoV-2 strains collected from COVID-19 patients, making this the largest sample of SARS-CoV-2 genes sequenced from patients in the southern U.S.
08-May-2020 02:40:28 PM EDT

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