PHILADELPHIA - Public health experts are warning of a dramatic increase in potentially severe antibiotic-resistant Staphylococcus aureus infections among children and other populations who until recently were not considered to be at risk. The information was presented today at the annual meeting of the Society for Healthcare Epidemiology of America, an organization of the nation's leading experts on healthcare associated infections, resistant organisms and other adverse events that occur in the healthcare setting.
One study reported that the overall prevalence of infections grew from 15 percent to 38 percent among children treated at Children's Hospital, Philadelphia. "More concerning is that the prevalence grew nearly 50 percent among children with soft tissue infections, many of which developed in the cuts, scrapes, insect bites and other minor injuries that occur everyday in active young children," said Susan Coffin, MD, medical director of infection prevention and control, Children's Hospital, Philadelphia, and division of infectious diseases, University of Pennsylvania School of Medicine.
Most staph infections develop in the soft tissues of the body, but if not treated effectively can lead to more serious, life-threatening conditions such as pneumonia, blood stream or bone infections, and surgical or other deep tissue infections.
"We are losing our antibiotic options for treating serious staphylococcal infections as fewer antibiotics remain effective," said Nancy Church, RN, manager of infection control at Providence St. Vincent Medical Center in Portland, Ore., who presented information at the SHEA meeting. "The best drugs for treating staphylococcal infections are derivatives of penicillin, but the new strain is resistant to the penicillin family of antibiotics and is known as MRSA (methicillin resistant staphylococcus aureus). Resistant Staphylococcus aureus is now becoming more prevalent in the community, and not just among people treated in the healthcare system.
"Using a data-mining surveillance tool that assists in identifying these cases, we noted a sudden increase in community MRSA infections. Our community MRSA strains have begun developing resistance to the antibiotic clindamycin as well as drugs of the penicillin class," Church said.
Until recently, it was rare to see MRSA infections except among healthcare workers and people with a recent history of treatment in hospitals or other healthcare facilities, where antibiotic-resistant strains of bacteria are known to be prevalent. Others traditionally at higher risk for MRSA, which is transmitted by direct physical contact, are men who have sex with men, people in prisons and members of athletic teams who are in close physical contact with each other.
Coffin studied the rate of community-onset MRSA infections among children, approximately half of whom had no history of contact with hospitals or healthcare facilities or other factors that would put them at risk.
"Its emergence among children, who do not typically fall into any of the traditional risk categories, suggests that many people not considered to be at risk may now be exposed to MRSA infections," she said. "These infections can be easily controlled if they are diagnosed early and treated with antibiotics to which they are not resistant. Any serious looking skin infection should be promptly seen by a doctor."
Church and Coffin emphasized the importance of educating healthcare providers and the public of the growing problem of community-acquired MRSA. Doctors may need to change the antibiotics they usually prescribe for staph infections if they suspect MRSA, which can be confirmed by laboratory analysis of a tissue culture taken from the wound. The public also should be alert to the signs of an infection that may require medical attention.
Potential symptoms of staph infection include:
-- A blister, boil or other skin wound surrounded by an area of redness or swelling
-- A wound that is unusually tender to the touch
-- A wound accompanied by systemic symptoms such as fever
"Most minor skin wounds will heal rapidly if they are washed with soap and water and kept clean. If the wound doesn't get better, or appears to become worse despite these measures, there may be a staph infection," Coffin said.
Staph bacteria are common, and can be found on the skin or in the nose of many healthy people. They usually are harmless unless they penetrate an open wound or sore on the skin, or take hold in a person whose immune system is compromised by some other disease or condition. According to Coffin, they may be prevented by:
--Washing thoroughly with soap and water any skin wound, no matter how minor, and keeping it clean.
-- Washing hands with soap and water after touching any wound.
-- Avoiding contact with or thoroughly cleaning any objects that may be contaminated, such as combs, soap, sheets, wash clothes and towels, and items commonly shared with others such as gym and workout equipment.
"From a community standpoint, the best way to prevent or reduce the prevalence of MRSA is to reduce the inappropriate use of antibiotics," Coffin said. "Antibiotics are indicated for the treatment of illnesses caused by bacteria, but they are frequently prescribed for conditions such as colds and other viral diseases, even though they are ineffective against viruses."
According to Coffin and Church, bacteria such as staph can mutate to develop resistance that enables them to live with the antibiotics to which they are exposed. Once they develop antibiotic resistance, these bacteria can lead to MRSA infections if they penetrate skin wounds, even minor ones, or otherwise invade the body making the bacterial infection harder to treat.
"When antibiotics are necessary, it is very important that patients take all of the medication prescribed, even if they no longer feel sick. An incomplete course of antibiotics makes it more likely that bacteria will survive and mutate to develop resistance," Church said.
The study of patients treated at Children's Hospital of Philadelphia included a review of three years of test results on cultures taken from sterile body fluids or from deep soft tissue wounds or abscesses. A total of 305 children were identified with community-onset staph infections, of which 79 (26 percent) were MRSA infections. Of these, half had a history of prior hospitalization or treatment in a healthcare facility and half had no known risk factors. Both groups were equally likely to have MRSA.
In the Portland study, the medical records of patients seen in the emergency room and treated for MRSA infections between May and August 2003 were reviewed. Some risk factors identified included intravenous drug use including methamphetamine, HIV infection and low income.
"More recently, however, we're seeing these infections in patients who have no known risk factors," Church said.
In the Philadelphia study, factors associated with as higher likelihood of MRSA infection included poverty and living in an urban, inner-city neighborhood. Other studies have found the following risk factors:
-- Recent antibiotic use
-- Sharing contaminated items such as combs, soap, washcloths
-- Having active skin diseases
-- Living in crowded settings
Co-author of the study presented by Church at the SHEA meeting is W. English, MD.
Co-authors of the study presented by Coffin are T. Abrams; J. Chu, MPH; S Alexander, BSN, RN, MT, CIC; T. Zaoutis, MD and K. McGowan, PhD.
The Society for Healthcare Epidemiology of America (SHEA) was organized in 1980 to foster the development and application of the science of healthcare epidemiology, which is broadly defined as activities designed to study and/or improve patient-care outcomes. Healthcare epidemiology includes a variety of disciplines and activities including epidemiologic and laboratory investigation, surveillance, risk reduction, policy, education and cost-benefit assessment.