July 29, 2011
Multi-Resistant Bacteria Increasing In Hospitals
(Ivanhoe Newswire)--Antibiotic resistance is a global issue that has been aggravated by the recent mergence of multi-resistant bacteria (MRB) in hospitals, health care establishments, and homes. Bacteria are considered multi-resistant to antibiotics when they develop a resistance to several families of antibiotics and therefore have a limited number of treatments. Multi-resistance is insidious because it renders certain infections untreatable. Since antibiotics have been introduced into chemical use, bacteria have protected themselves by developing these antibiotic resistance mechanisms. A lack of compliance with basic cleanliness measures eases the spread of MRB's through personal contact as well as through contacting a contaminated environment.
The amount of multi-resistant bacteria is starting to increase in hospitals. A research team at the Portuguese CBA research center (University of Lisbon) and the Instituto Gulbenkian de Ciencia has shown that when mechanisms of resistance are playing out in the bacteria E. coli, its ability to survive and reproduce increase. Bacteria acquires resistance to antibiotics through mutations in their chromosomes and by incorporating new genes either from their surrounding environment or from other bacteria. Typically the acquisition of new genes comes at a cost to the bacterium that is reflected in a reduction of its cell division rate. Francisco Dionisio, senior author of the paper, was quoted describing this process through the following analogy, "If you disassemble your computer and randomly changed connections and pieces, you wouldn't expect it to work better than before."
Francisco and his colleagues found that when mutation occurs within the chromosome of a bacterium that has already become resistant, the bacteria divide faster. Similarly, the bacteria that first acquired resistance to antibiotics through mutation of their chromosome gain further resistance and show reproduction rate increases in 32 percent of combinations. This study demonstrates their findings as a general phenomenon and therefore may help to predict how a bacterial population will evolve after receiving a plasmid that becomes resistant to a certain antibiotic.
SOURCES: PLoS Genetics, July 28th, 2011