U.S. "super bugs" invading South America

WASHINGTON, Nov. 12 (Chinese media) -- Two clones of highly

antibiotic-resistant organism strains, which previously had only been identified

in the United States, are now causing serious sickness and death in several

Colombian cities, say researchers at The University of Texas Medical School.

The study, done in collaboration with Colombian

researchers, is published on Wednesday in the New England Journal of Medicine.

U.S. clones of methicillin-resistant Staphylococcus

aureus (MRSA) and vancomycin-resistant Enterococcus faecalis (VREF) have emerged

in communities across Colombia. The variation of the MRSA clone, referred to as

the USA 300, has been previously reported to be the most important cause of

severe skin and soft tissue infections in the United States. The VREF clone is

genetically related to a strain that hit a Houston hospital in 1994.

In Colombia before 2005, there were no recorded cases

of any community-associated MRSA infections, including USA 300 MRSA. In 2005,

there were two: one in Bogota and one in the city of Villavicencio. Now the

number of MRSA infections is climbing across the country.

The paper reports a total of 15 infections, some of

which were documented in two additional cities between 2006 and 2007.

USA 300 MRSA has also been recorded in multiple

patients in Ecuador and Venezuela.

The first case of VREF was reported in Bogota in

2001. Since then, 50 additional cases have been identified at seven hospitals.

"The goal is to find out why and how these organisms

got there. With this information, researchers hope to better understand the

molecular epidemiology of these super bugs to understand how they spread and how

to control them," said Cesar Arias from UT medical school.

All patients diagnosed with community-associated MRSA

infections suffered severe skin and soft-tissue infections. Some patients also

experienced death of tissue surrounding bones, bacteria in the bloodstream and

meningitis, and 20 percent of the patients died. The MRSA infections were

treatable with common antistaphylococcal antibiotics, although 40 percent were

resistant to tetracycline.