Group A strep exposures may warrant prophylaxis
Risks to HCWs, family contacts may be considered
Reports of nosocomial clusters of Group A streptococcus infections as recently reported in the maternity unit of a Rochester, NY, hospital may raise questions about whether health care workers should receive post-exposure prophylaxis. (See related story in Hospital Infection Control, May 1997, pp. 68-70, 75.)
Though no official recommendations are in place for administering post-exposure prophylaxis to health care workers exposed to patients with Group A streptococcus, infection control professionals may want to consider the measure in cases of severe exposure, clinicians report.
Some strains of strep are particularly virulent and have the ability to produce toxins or antigens that result in streptococcal toxic shock syndrome. There is a low but real risk that severe strep infections can be spread to contacts of the patient that might include health care workers and family members. The primary concern in clinical settings is that streptococcal toxic shock syndrome could be transmitted directly to a heath care worker from an infected patient, as in the case of an emergency medical worker who was infected within 24 hours of resuscitating an infected child.1
Look for significant exposure’
The Centers for Disease Control and Prevention has held workshop meetings to consider some formal recommendations, but no official guidance has been issued. However, ICPs may want to consider post-exposure prophylaxis in cases of significant exposure to a severely infected patient, a CDC epidemiologist advises.
"We know that when you have a cluster of cases and the primary case has been streptococcal toxic shock, a secondary case will likely be streptococcal toxic shock as well," says Benjamin Schwartz, MD, medical epidemiologist in the CDC childhood and respiratory diseases branch. "If a health care worker had significant secretion exposure to a patient with streptococcal toxic shock syndrome, I think it is worth considering the question of providing chemoprophylaxis."
A similar approach is recommended by Allison McGeer, MD, director of infection control at Mount Sinai and Princess Margaret Hospitals in Toronto, and a clinical researcher with the Ontario Group A Streptococcal Group.2
"The situations in which we recommend prophylaxis for health care workers are severe invasive disease in the patient which is toxic shock [or] necrotizing fasciitis that causes death within the first 48 hours and the health care worker has had unprotected exposure to potentially infective secretions," she says. "We have no data to justify that. All we know is that there are two cases in the literature that I am aware of where health care workers have developed severe disease after an exposure. We know that overall the risk of acquiring disease is low, but the cost and risks of prophylaxis are small enough that we do it in those circumstances. But those are the only circumstances."
In general, such an exposure would not occur to a health care worker unless there was a break in technique or failure to use standard infection control measures such as handwashing and barrier precautions. Antimicrobials used for prophylaxis include a regimen of cephalexin and erythromycin over 10 days. More likely candidates for post-exposure prophylaxis may be household contacts of infected patients, particularly those who share sleeping arrangements or have had direct mucous membrane contact within one week prior to the patient becoming ill, McGeer and colleagues recommend.3
"Health care workers do get [mildly] infected, but in general their risk of serious disease is so much lower that it is probably not relevant," she says. "The risk of invasive infection in household contacts is about 200 times the risk of infection in the general population probably somewhere on the order of two per 1,000 contacts. In my mind, the risk associated with household contact is high enough and the degree of protection is high enough to warrant prophylaxis."
References
1. Valenzuela TD, Hooton TM, Kaplan EL, et al. Transmission of toxic strep’ syndrome from an infected child to a firefighter during CPR. Ann Emerg Med 1991; 20:90-92.
2. Davies HD, McGeer A, Schwartz B, et al. Invasive Group A Streptococcal infections in Ontario, Canada. N Engl J Med 1996; 335:547-554.
3. Green K, McGeer A, Low DE. Group A strep: A killer makes a comeback. Medicine North America 1996; S8:53-58.
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