ISLAMABAD: New research analyzes the effect of cigarette smoke on MRSA strains and finds that it makes the bacteria more persistent more invasive and more resistant to certain antibiotics. Smoking is the leading cause of preventable death across the world with tobacco use including smoking being responsible for over 7 million fatalities each year. In the United States over 16 million people have a smoking related condition and tobacco smoking causes 1 in 5 deaths each year. Researchers and healthcare professionals know that smoking impairs a person s immune system and the defenses against infections. However they do not know much about how cigarette smoke affects microbes that live in the nasopharyngeal cavity in particular. A new study aims to remedy this gap in research by examining the effect of cigarette smoke on Staphylococcus aureus (S. aureus). Maisem Laabei from the Department of Biology & Biochemistry at the University of Bath in the United Kingdom is the lead author of the new research which appears in the journal Scientific Reports. Dr. Laabei explains the motivation for the research saying We wanted to study S. aureus because it s so common in humans and it can cause a range of diseases so we wanted to see what happened when we exposed it to smoke. S. aureus is part of the nasal microflora of 30 60% of people. The pathogen can cause various infections that can range from minor such as superficial skin infections to very severe and potentially fatal such as pneumonia or endocarditis. Antibiotic resistant strains of S. aureus are a significant contributor to the microbial resistance public health crisis. Methicillin resistant S. aureus (MRSA) specifically causes 94 360 invasive infections each year in the U.S. and about 18 650 people die as a result. MRSA is a clonal pathogen explain the researchers and several studies have singled out a few predominant clones that are responsible for the majority of the global prevalence of MRSA and subsequent disease burden.