Cigarette Smoke Can Make Drug-Resistant Superbugs Even Stronger

By: Christopher Wanjek
Published: April 06, 2015 04:27pm ET

Cigarette smoke apparently isn’t deadly for all living creatures. At least one type of bacterium — MRSA, the superbug commonly found in hospitals — apparently thrives on the stuff.

In fact, cigarette smoke makes MRSA stronger and more resistant to antibiotics, which could mean it is worse for human health, according to a new study. The surprise finding appears online this month in the journal Infection and Immunity.

MRSA, short for Methicillin-resistant Staphylococcus aureus, is a type of “staph” bacterium resistant to most antibiotics and is capable of causing life-threatening skin and bloodstream infections as well as pneumonia.

In 2005, MRSA caused nearly 19,000 deaths in the U.S., according to the Centers for Disease Control and Prevention. In recent years, however, the number of infections has decreased by more than 25 percent, and in 2012 there were about 10,000 MRSA deaths, according to CDC data.

The new study began after Dr. Laura Crotty Alexander, a pulmonologist at the VA San Diego Healthcare System, noticed that many of the patients she treated who were smokers had MRSA infections, and wondered whether there was a connection.

Crotty Alexander and her colleagues at the University of California, San Diego, created two batches of MRSA in their lab — one grown normally and the other grown with exposure to cigarette smoke. They then infected human immune cells called macrophages with each of these MRSA samples. Macrophages are a type of white blood cell, and are among the first line of defense to attack MRSA and other sources of infections. [6 Superbugs to Watch Out For]

The macrophages could kill both samples, but they had a much harder time killing the MRSA exposed to cigarette smoke. Digging deeper, the researchers found the reason.

Macrophages kill foreign invaders by engulfing them —> Read More