Strep guidelines emphasize rapid action, surveillance
In recently reporting two nosocomial outbreaks of Group A streptococcus (GAS), the Centers for Disease and Prevention issued information and prevention measures, which are summarized as follows:
GAS, a common cause of pharyngitis and uncomplicated skin and soft-tissue infections, can cause serious invasive infections, including necrotizing fasciitis, streptococcal toxic-shock syndrome, and death.1 The CDC estimates that 10,000 cases of invasive disease occur annually in the United States, causing about 1,000 deaths. Most cases are community-acquired, but nosocomial outbreaks do occur and warrant prompt investigation. Since 1965, at least 15 postoperative or postpartum GAS outbreaks attributed to asymptomatic carriage in health care workers (HCWs) have been reported.2 GAS is an unusual cause of surgical site or postpartum infections. The bacterium is isolated from less than 1% of surgical-site infections and 3% of infections after vaginal delivery.3 The most common site of asymptomatic carriage among HCWs is the anus, but vaginal, skin, and pharyngeal carriage have been implicated.4-9 Carriers can shed the organism into the immediate environment despite proper gowning and gloving. The mode of transmission is presumed to be airborne. Surgical and obstetric patients are particularly vulnerable to infection because broken cutaneous or mucosal barriers facilitate invasive infection after exposure.
Preventive measures: To prevent additional nosocomial GAS infections, enhanced surveillance and limited epidemiologic investigation are warranted following one episode of nosocomial GAS infection on a surgical or obstetric ward. After identification of a patient with postoperative or postpartum GAS, medical and laboratory records should be reviewed to identify other infections, and isolates from infected patients should be stored and surveillance heightened to identify additional episodes. When an episode of postoperative or postpartum GAS is identified, limited HCW screening should be undertaken. Most nosocomial transmission is traced to carriers involved in direct patient care. For a postpartum GAS-infected patient, screening should include all HCWs present at the delivery and those who performed vaginal examinations before delivery. For a postoperative GAS-infected patient, screening should include all HCWs present in the operating room during the procedure and those who changed dressings on open wounds. Screening of HCWs should include culture of the nares, throat, vagina, rectum, and skin. HCWs may return to work pending culture results.
Antimicrobials: Any HCW who is culture- positive for GAS should refrain from patient care for the first 24 hours of antimicrobial treatment. The regimen should be tailored to the carriage site; previous reports have indicated anal carriage may be difficult to eradicate. For example, appropriate treatment for a positive rectal culture may be vancomycin 250 mg orally four times a day and rifampin 600 mg orally twice a day for 10 days. For a positive throat, vaginal, or skin culture, appropriate treatment may be penicillin 500 mg four times a day for 10 days with rifampin 600 mg orally twice a day for the last four days of the 10-day course. If surveillance identifies additional patients or HCWs with positive cultures for GAS, the isolates should be typed by emm, serologic, or other molecular methods to identify the strain. When the isolates are the same and a carrier has not been identified, screening should be expanded to include HCWs who had less direct patient care. CDC also recommends obtaining cultures from household contacts of implicated carriers to identify and treat potential reservoirs for reinfection. Because carriage may recur, implicated carriers should be monitored with periodic surveillance cultures for one year after treatment.
References
1. Centers for Disease Control and Prevention. Nosocomial group A streptococcal infections associated with asymptomatic health-care workers — Maryland and California, 1997. MMWR 1999; 48:163-166.
2. Kolmos HJ, Svendsen RN, Nielsen SV. The surgical team as a source of postoperative wound infections caused by Streptococcus pyogenes. J Hosp Infect 1997; 35:207-214.
3. Mastro TD, Farley TA, Elliot JA, et al. An outbreak of surgical-wound infections due to group A Streptococcus carried on the scalp. N Engl J Med 1990; 323:968-972.
4. Schaffner W, Lefkowitz LB Jr, Goodman JS, et al. Hospital outbreak of infections with group A streptococci traced to an asymptomatic anal carrier. N Engl J Med 1969; 280:1,224-1,225.
5. Viglionese A, Nottebart VF, Bodman HA, et al. Recurrent group A streptococcal carriage in a health care worker associated with widely separated nosocomial outbreaks. Am J Med 1991; 91:S329-S333.
6. McKee WM, DiCaprio JM, Roberts CE Jr., et al. Anal carriage as the probable source of a streptococcal epidemic. Lancet 1966; 2:1,007-1,009.
7. Stamm WE, Feeley JC, Facklam R. Wound infections due to group A Streptococcus traced to a vaginal carrier. J Infect Dis 1978; 138:287-292.
8. Berkelmam RL, Martin D, Graham DR, et al. Strepto coccal wound infections caused by a vaginal carrier. JAMA 1982; 247:2,680-2,682.
9. Paul SM, Genese C, Spitalny K. Postoperative group A beta-hemolytic Streptococcus outbreak with the pathogen traced to a member of the healthcare worker’s household. Infect Control Hosp Epidemiol 1990; 11:643-646.
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