CAMP Resistance in Serratia marcescens

Graduate #25
Discipline: Biological Sciences
Subcategory: Microbiology/Immunology/Virology

Jessica Cole - Claflin University


According to the Center for Disease Control, 40-90% of contact lens wearers do not follow the proper care instructions for their corrective eyewear. Inadequate cleaning and irregular replacement of contact lens cases may lead to complications, such as keratitis or inflammation of the cornea. Keratitis results in nearly one million doctor and emergency room visits and costs the United States healthcare system $175 million yearly. Serratia marcescens causes 10-15% of bacterial keratitis cases. The bacteria have intrinsic high level resistance to cationic antimicrobial peptides (CAMPs), therefore promoting the infection. CAMPs are secreted by corneal epithelial cells and have a protective role in the human innate immune system. We hypothesize that S. marcescens has a set of genes whose products alter the direct interaction of the peptides with the bacteria. To this end, we have generated approximately 9,400 mutants by transposon mutagenesis and screened the mutants for sensitivity to the CAMP polymyxin B. Replica plating identified four mutants that were more sensitive to 100 ug/ml or 500 ug/ml of polymyxin B than the parent strain. The defective genes in the mutants will be cloned and sequenced. Their identity will be determined by comparing their sequences to those in the Genbank database. Identifying which genes are responsible for CAMP-resistance will lead to the development of shorter treatment and recovery times.

Not Submitted

Funder Acknowledgement(s): Awarding Agency: US Department of Education. Project Name: Historically Black Colleges and Universities Master's Degree Program Award Number: P382G090010

Faculty Advisor: Randall Harris, rharris@gmail.com