UVa researchers develop staph-fighting technique

University of Virginia researchers have discovered a technique to reduce drug-resistant staph infection among patients in the surgical intensive care unit.

By switching the type of antibiotic given to patients every three months at the UVa Medical Center, the researchers were able to decrease the infection rate from 1.9 patients per 100 admissions to 1.4 patients during a six-year study. The in-hospital mortality rate for patients who contracted methicillin-resistant Staphylococcus aureus infections decreased from 3.8 patients a year to none.

Dr. Robert G. Sawyer, an associate professor at UVa and the co-director of the Surgical Trauma Intensive Unit, and other researchers published the study in the Sept. 3 issue of the journal Surgical Infections.

Sawyer said antibiotic cycling seemed to prevent MRSA bacteria from developing resistance and staying around the ICU.

“We were able to get rid of a large reservoir of MRSA in our unit, making our patients less likely to be infected with MRSA and die from it,” Sawyer said.

Staphylococcus aureus is a common bacterium, susceptible to antibiotics, that can live on the skin. MRSA is a type of staph infection that is resistant to common antibiotics. The bacteria can infect open sores such as surgical wounds, or appear as a boil or pimple-like bump if it’s the community-acquired strain.

According to Elizabeth Davies, the senior epidemiologist with the Thomas Jefferson Health District, there have been 27 cases of the hospital strain of MRSA within the district so far in 2008. The agency started surveillance on the hospital MRSA cases in October.

“Hospital-acquired MRSA is when you isolate the MRSA strain from a normally sterile site, [such as] blood, bone or synovial joint fluid,” Davies said.

MRSA gained nationwide attention last year when some middle and high school students contracted the community-acquired strain of the infection. Last October, a Bedford County youth died after being infected. The infection prompted some schools to perform more thorough sanitizations of their schools and encourage regular hand washing among students.

According to the Centers for Disease Control and Prevention, hospital-acquired MRSA is mainly transmitted by touch. Doctors and nurses are encouraged to wash their hands often to prevent bacteria from one infected patient being transmitted to a healthy one. Healthcare workers can pick up the disease after working with patients who are infected or who are colonized with the bacteria but don’t appear infected.

Sawyer said MRSA usually is treated with vancomycin, but doctors have started to use linezolid in about 15 percent of cases. In the UVa study, researchers used both.

The doctors monitored MRSA infections in the ICU from 1997 to 2001, and then started switching between prescribing vancomycin and linezolid alternately in 2002 and 2003. According to Sawyer, all UVa patients in the surgical ICU unit for trauma or general surgery were part of the study. Burn patients were excluded.

Sawyer, who does research on infections related to surgery and critical illness, said more research needs to be done at other ICUs to make sure the technique is effective. For now, UVa’s surgical ICU has stopped cycling the antibiotics and started monitoring patients to see what happens to the infection rate.

The CDC recommends regular hand washing to prevent both the hospital-acquired and community-acquired strains of MRSA.