Health care workers should be on the lookout for community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA), according to a “Concise Communication” in the October issue of Infection Control and Hospital Epidemiology (2006;27:1133–1136).
Cecilia Johnston, MD, MHS, an instructor in the Division of Infectious Diseases at Johns Hopkins School of Medicine, and colleagues investigated soft-tissue infections caused by community-acquired MRSA strains in two health care workers employed in an outpatient clinic for patients with HIV at Johns Hopkins Hospital.
The authors suspect that the infections in these workers were the result of occupational exposure, she said.
“Hospitals need to have a strong infection-control program. The most important thing is recognition that this [CA-MRSA infection] is going on and to have a multidisciplinary approach, from the physicians down to the people who clean the hospital that they be aware of potential bacteria or viruses that are in the environment.”
Once the infection of the two health care workers was confirmed, Dr. Johnston and her colleagues sought to identify the scope of contamination and any other health care workers who may have been exposed.
This investigation, which was conducted from August to November 2004, involved the completion of a survey by each health care worker in the clinic. The survey asked about a current or past history of MRSA infection.
Approximately 138 health care workers were employed at the clinic, of whom 58 performed administrative duties and 80 had clinical responsibilities. The clinic has 20,000 patient visits each year.
Surveillance cultures were obtained from the anterior nares and hands of these health care workers in order to detect MRSA colonization. In addition, environmental cultures of the clinic were taken of surfaces that were frequently touched.
One of the infected health care workers reported caring for 15 patients with CA-MRSA infections during the preceding several months and incising and draining many of the abscesses.
This health care worker developed furuncles on the chest, and cultures of the lesions grew MRSA. Clindamycin was used successfully to treat the infection.
The other health care worker worked in an administrative position without direct patient contact. This individual developed a buttock abscess that required incision and drainage, and received clindamycin followed by trimethoprim-sulfamethoxazole to resolve the symptoms.
The workers were not colonized with MRSA in their anterior nares. They had not been hospitalized recently and had not had household contacts with MRSA infections; family members weren't screened during the study.
“The good news was that aside from these two health care workers, no one else had a problem with MRSA infections,” Dr. Johnston said.
However, two additional health care workers were found to be colonized with hospital-acquired MRSA (HA-MRSA) in both the anterior nares and on their hands, and they were treated with intranasal mupirocin 2% ointment. Follow-up nasal cultures for these health care workers were negative for MRSA.
An additional health care worker had a culture of hand specimens that grew MRSA, but additional cultures were negative.
Patient care providers reported having seen a median of two patients with MRSA infections in the past two months.
Staff interviews also revealed that patients with CA-MRSA infections had their abscesses drained and wounds cleaned in whichever room was available and that some of the staff wore no protective gowns or masks during the procedure.
Contaminated Outpatient Clinic
Seven (19%) of the 36 environmental cultures taken in the clinic grew MRSA, including a patient examination table, a computer keyboard, a pulse oximeter, and multiple patient chairs.
Other sites that were sampled but didn't yield S. aureus included door knobs, telephones, ophthalmoscopes, otoscopes, blood-pressure cuffs, scales, thermometers, and sinks. No methicillin-susceptible S. aureus strains were isolated from the environment.
Before this investigation, each health care worker who provided patient care was responsible for cleaning an assigned room in the clinic between patient visits, disposing of used gowns, and pulling a new length of paper across the examination table. No additional cleaning occurred between visits, even though the clinic was cleaned daily.
The hospital's environmental service department was notified of the contamination of the surfaces. The clinic was cleaned thoroughly, and the surfaces were disinfected using quaternary ammonium.
“We talked to the hospital's environmental services department, presented these findings, and basically gave them feedback,” said Dr. Johnston.
“The environmental services department did a wonderful job of cleaning the clinic and also reinforced what surfaces were cleaned on a daily basis. We also put in more alcohol-based hand sanitizers so that health care workers could disinfect their hands easily.”
Prevention & Control
Other changes were also implemented in the clinic, including placing disinfectant wipes containing ethyl alcohol and quaternary ammonium in each examination room with recommendations to clean surfaces.
It is unknown how long CA-MRSA strains can survive on fomites, although the authors speculate that it is at least several days, given the extent of the contamination in the clinic.
The use of keyboard covers was also recommended to use in between routine keyboard cleanings. All environmental cultures performed after the cleaning were negative for MRSA.
The results show that the environment can be contaminated with toxin-producing strains of CA-MRSA and suggest that prevention and control measures include the cleaning of the hospital environment daily.
Issues related to the prevention of the spread of MRSA are particularly relevant in outpatient clinics with high volumes of patients with CA-MRSA infections, such as emergency rooms, urgent care clinics, and other primary care clinics, Dr. Johnston noted.
“The major significance is that infection control is on the radar for hospitals, especially the inpatient units, but this study highlights that it is also important for outpatient units.”