Clostridium expands its targets and virulence
Trish Perl, MD, director of hospital epidemiology at The Johns Hopkins Hospital in Baltimore, called a December 2005 CDC report on Clostridium difficile a "landmark" in understanding the virulence of a new strain of this pathogen. She also applauded that study's documentation of the problems that C difficile diarrheal disease can cause in children.
The report was based on investigations in four states that found what appears to be community-acquired C difficile in 33 otherwise healthy, low-risk people-a critical and startling discovery, considering that the organism is typically associated with nosocomial infection.
"We think that this is a re-emerging pathogen," said Dr. Perl. Re-emergence, she pointed out, appears to be associated with resistance-primarily to fluoroquinolones. Researchers, she said, are beginning to feel confident that there has been a true increase in the incidence of C difficile diarrheal disease and in its severity.
Studies from several localities have reported a doubling of life-threatening cases and an increase in the rate of associated colectomy and death, Dr. Perl noted. A study from Quebec estimated a greater-than-fourfold increase in incidence and greatly increased morbidity and mortality.
This pathogen will present a challenge, said Perl, as it moves into the community. The need to educate people about cleaning surfaces and washing hands, including in day care centers, will increase. And there remains, she said, the continuing challenge of educating the health-care community on judicious use of antimicrobials, in light of an apparent association between the rising virulence of C difficile and the indiscriminate use of antimicrobials.
Here, then around the world, with MRSA?
The press conference also brought Carol Baker, MD, head of the Baylor College of Medicine section on infectious diseases, to the podium to speak about community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA). The infection, she said, can be found in every urban center in the country, and is moving so fast that she will be "absolutely surprised" if it has not traveled around the world shortly.
Dr. Baker summed up recent experience in her region: "Between August 2001 and July 2004, there were 2,666 children with CA-MRSA infection in Texas Children's Hospital-75% of all staph infections in the inpatient and outpatient departments."
Surveillance has revealed a doubling or tripling of the total number of S aureus infections that are caused by this new clone-most, she noted, probably caused by the strain that the CDC has dubbed "USA 300."
"Clearly, it is not only promiscuous, but has a real survival skill as a bacterium," Dr. Baker said.
Baker, pediatrician and president of NFID, had an emphatic message for pediatric colleagues: "When you see a skin or soft tissue infection, get a culture on the first visit. If you see pus that needs to be drained, drain it right away, because you cannot cure an abscess with antibiotics alone."
Noting that CA-MRSA is a highly pus-creating organism, but that most patients don't feel ill at their initial visit, she urged physicians to tell patients, and parents of young patients, to return to the office if they observe an accumulation of pus or if swelling, further pain, headache, or muscle ache develop.
Since 1998, when CA-MRSA was first described in a few Chicago children, Dr. Baker said, the infection has been shown to be genetically distinct from all previously known S aureus bacteria. CA-MRSA has significantly increased the incidence of skin and soft-tissue infections in previously healthy children and adults in the community, and has caused epidemics among members of sports teams, day care-center attendees, and military recruits. Children are more likely to be infected; other risk factors include poverty, obesity, membership in an ethnic minority, and participation in contact sports.
Dr. Baker also reported that CA-MRSA is showing up in hospitals-including in very small premature babies who have been hospitalized since birth.
Preventive measures, she says, include practicing good hygiene, avoiding skin trauma to the greatest extent possible, covering open wounds, and maintaining good nutrition-the latter to both support the immune system and stave off obesity.
In Baylor's service region, Dr. Baker said, staff who supervise school athletic teams have undertaken campaigns to ensure that each player has his (or her) own towel; that towels are not shared; that players take a shower with hot water and soap after each event; and that older boys don't share a razor.