Superbug's source

Feeding antibiotics to livestock can affect human health

source: New Scientist vol 213 no 2853, February 25 2012 p4

A type of MRSA, or antibiotic-resistant staphylococcus aurea, probably became resistant when it affected livestock. The ST398 strain was first recorded in 2003, and is found in animals in the USA. The bug can cause sepsis and skin infection in humans who have contact with infected animals, though humans do not catch it from other humans. Paul Keim and team from Phoenix Arizona's Translational Genomics Research Institute have sequenced MRSA and other S aurea genomes. They have found that ST398 may have originated as a harmless bacteria initially colonising humans, and then livestock. It developed antibiotic resistance in livestock which were given antibiotics. The dosing of livestock with antibiotics on a large scale could encourage antibiotic resistance, microbiologists fear. Only a small proportion of antibiotics is covered by recent restrictions on their usage in the USA.