The National Necrotizing Fasciitis Foundation says:
First, let it be said that there is no sure prevention. Necrotizing fasciitis has been known to be spontaneous. A bruise or abrasion are
all the "opening" in the skin necessary for bacteria to enter.
However, there are some things you can do decrease risk.
The single biggest preventative measure is keeping the skin intact!
Next is cleanliness. Always wash even the smallest opening in the skin and apply an antibiotic ointment. Buy tubes of antibiotic
ointment and keep one in your car, your desk, your exercise bag, and
Take care with your children, impressing upon them the importance of cleanliness.
Be respectful to protect others from infection if you suspect that you may have a Strep infection, such as Strep throat, or have been
exposed to someone with a known Strep infection. Symptoms do not have
to be present for a person to be carrying the bacteria and infect
others. One case of infection that comes to mind is a health care
worker with two children at home with Strep throat. She had no
symptoms, but innocently infected three people, one of whom died.
These simple measures are the most protection one can give oneself
against any infection. It just can't be stressed enough, however, that
a pin prick (one woman became infected at the point of entry from a
blood draw) can be the opening it takes.
(This is not an endorsement for the entity known as The National Necrotizing Fasciitis Foundation.)
The CDC says:
The spread of all types of GAS infection can be reduced by good hand
washing, especially after coughing and sneezing and before preparing
foods or eating. Persons with sore throats should be seen by a doctor
who can perform tests to find out whether the illness is strep throat.
If the test result shows strep throat, the person should stay home
from work, school, or day care until 24 hours after taking an
antibiotic. All wounds should be kept clean and watched for possible
signs of infection such as redness, swelling, drainage, and pain at
the wound site. A person with signs of an infected wound, especially
if fever occurs, should immediately seek medical care. It is not
necessary for all persons exposed to someone with an invasive group A
strep infection (i.e. necrotizing fasciitis or strep toxic shock
syndrome) to receive antibiotic therapy to prevent infection. However,
in certain circumstances, antibiotic therapy may be appropriate. That
decision should be made after consulting with your doctor.
According to this LA Times article Aimee Copeland's infection was apparently caused by Aeromonas hydrophila which is a less common agent in necrotizing fasciitis:
Necrotizing fasciitis is typically caused by an especially aggressive form of Group A Streptococcus, according to the federal Centers for Disease Control and Prevention's website. But not always. Copeland's father, Andy Copeland, told the Atlanta Journal Constitution that Aeromonas hydrophila caused his daughter's rare bacterial infection.
The article states, quoting microbiologist Amy Horneman:
Infections caused by the bacterium are relatively easy to treat with common antibiotics -- but only if recognized in time. "There are certain drugs that just don't work," she said. "The best drugs to use are Ciprofloxacin and Bactrim (also SXT, Septra)."
Naturally occurring in water sources throughout the world, Aeromonas hydrophila bacterium has many positive contributions to the eco-system, she said.
"When I heard about the case, and I heard she fell in the water and got a deep cut... I thought, 'It must be Aeromonas hydrophila,'" Horneman said.
"I am not an alarmist," she said, noting that she raised two sons and allowed them to participate in water-related sports and activities. "But I am very aggressive about treating any kind of cut, any kind of wound infection."
She advises the public to seek medical attention for such wounds, but again stressed: "Not all wounds become necrotizing fasciitis."
From this one might conclude that all injuries exposed to river water should receive special attention, perhaps even antibiotics.