Antibiotic-resistant bacteria spreading worldwide

The University of Iowa has reported that some strains of the bacteria Staphylococcus aureus (S. aureus) have become antibiotic-resistant globe trotters, spreading throughout the world.

S. aureus is the most common bacterial cause of human diseases, including infections of the lung, bloodstream, heart valves, skin and those infections caused by surgical wounds.

Daniel Diekema, M.D., a University of Iowa pathology fellow and infectious diseases staff physician, stated that similar and sometimes identical antibiotic-resistant strains of S. aureus are popping up hundreds and thousands of miles apart, even across oceans.

"We demonstrated that there are numerous instances where bacterial strains were present at many different hospitals in the same region and at hospitals on different continents," Dr. Diekema explained.

The medical community has been using antibiotics to treat bacterial infections for more than 60 years. However, many strains have become immune to most of the available drugs meant to destroy the organisms. Much of this immunity, or resistance, is due to overuse of the drugs themselves.

To conduct the probe, the UI team relied on the global network of 72 medical centers that participate in the SENTRY Antimicrobial Surveillance Program. The program is the first and only worldwide monitoring system for the spread, over time, of bacteria resistant to antibiotics.

"We did this particular study because it is very important to understand how these resistant strains are being spread around the world," Diekema said.

The findings, which showed that many of the resistant strains cross national borders and that the biggest resistance problem areas are located in Central and South America and in Asian-Pacific countries, are important as infectious disease control specialists attempt to combat the resistance, Diekema stressed.

"If resistance emerges within an individual hospital because of antibiotic use, then the best way to control that resistance is to crack down on antibiotic use," he said. "However, if very resistant strains are being spread widely between hospitals, then the best approach is to emphasize infection control practices.

"In the case of S. aureus," Diekema continued, "it looks like these resistant strains are very easily spread in hospitals, among hospitals and even across continents. What that means to us is that even though antibiotic control is important for this bacteria, even more important probably are good infection control practices."