My laboratory seeks to understand how the respiratory pathogen Streptococcus pneumoniae (pneumococcus), a gram-positive, extracellular bacterium, causes disease in humans and how human defense mechanisms, including breast milk, can better protect us from infection. Our team of undergraduate students, graduate students, a technician and a senior scientist work together and with several national and international collaborators to develop a better understanding in two areas.

First, we are interested in the protective effects of breast-feeding on bacterial infection. We have identified a protein-lipid complex in breast-milk, HAMLET (human alphalactalbumin made lethal to tumor cells) with strong bactericidal activity against S. pneumoniae and other respiratory tract pathogens. HAMLET‘s activity is especially important because it represents a new way to kill bacteria, even those resistant to antibiotics: it uses an essential pathway that the bacteria cannot become resistant against. Our current projects aim to understand the mechanism of HAMLET-induced bacterial death and the potential use of HAMLET or its targets in preventing and treating biofilm formation in vitro and established pneumococcal infections in vivo.

Second, we study how bacterial factors promote colonization and biofiom formation in the nasopharynx and the mechanistic aspects of transition from colonization to infections such as otitis media and pneumonia. We especially interested in the environmental conditions affecting this transition including virus infections. and the host mucosal innate and adaptive immune responses. Our current project aims to understand disease progression for future development of novel antibiotics.