March 3, 1999
Invasive Group A Streptococcal Infections Update
Dear Infection Control Practitioner:
Please distribute this communication to infectious disease physicians who practice in your hospital, emergency department physicians, laboratory personnel and other interested parties.
An increase in reported invasive group A streptococcal infections (GAS) with dates of onset since December 15, 1998 has been identified in Cook, DuPage, Kane, Lake and McHenry counties; 37 cases have been reported during that interval compared to 34 cases during the same time period in 1998 and a five-year median of 16 cases. The distribution of cases by county is as follows: Cook, 22 cases (3 deaths); DuPage, 3 cases (1 death); Kane, 7 cases (3 deaths); Lake, 4 cases (1 death); and McHenry, 1 case (1 death).
Cases of invasive GAS are usually exposed by direct contact with respiratory secretions of persons who carry this organism in their pharynx. Symptomatic individuals are more communicable than those who are only colonized. Fomites do not play a major role in transmission.
Certain strains of GAS are more likely to cause invasive disease than are others. Although not totally clear why some strains are more likely to cause invasive disease, production of toxins and proteases is believed to be responsible. Necrotizing fasciitis (NF) and streptococcal toxic shock syndrome (STSS) are two particularly severe forms of invasive GAS infection with case fatality rates of approximately 20 percent and 60 percent, respectively. Other forms of invasive GAS have fatality rates between 10 percent and 15 percent.
Although healthy persons can develop invasive GAS infections, most persons who come in contact with a virulent strain of GAS do not develop invasive disease. Those at increased risk are patients with chronic illnesses including cancer, diabetes, those receiving chronic renal dialysis or taking steroids, and persons with breaks in the skin (including patients with varicella).
Invasive GAS infections can be confirmed by isolating GAS from a normally sterile site.
The need to offer chemoprophylaxis to close contacts of patients with invasive GAS infections is not clearly defined. In 1995, the Centers for Disease Control and Prevention (CDC) convened a working group to develop policy on prophylaxis of household contacts. The working group concluded, in an article published in the Journal of the American Medical Association dated April 15, 1998, that current data are insufficient to make definite recommendations, but that physicians base their decisions on chemoprophylaxis on their
assessment of the risk associated with each individual case. Additionally, the American Academy of Pediatrics, in a statement published January 1, 1998 in Pediatrics makes a similar statement and further states that chemoprophylaxis is not recommended in schools or child care facilities.
Physicians may wish to consider chemoprophylaxis of persons in close contact to persons with severe invasive GAS infection such as NF and STSS. When chemoprophylaxis is considered, the CDC offers several chemoprophylaxis alternatives:
| PEDIATRIC | ADULT | ||
| 1. | Azithromycin | 12 mg/kg/day PO daily x 5 days | 500 mg PO x 1 day, then 250 mg daily x 4 days |
| 2. | Cephalexin | 30 mg/kg/day PO div q 12 hrs x 10 days | 500-1000 mg PO q 12 hrs x 10 days |
| 3. | Clindamycin | 20 mg/kg/day PO div TID x 10 days (Max 450 mg/day) | 150 mg PO TID x 10 days |
| 4. | Benzathine Pen PLUS Rifampin* |
<27 kg 600,000 U IM x 1 or >27 kg 1.2 million units IM x 1 10 mg/kg PO q 12 hrs (max 600 mg/day) |
1.2 million units IM x 1 10 mg/kg PO q 12 hrs (max 600 mg/day) |
| *Rifampin should be administered on days 7, 8, 9 and 10 after injection. Day of injection defined as day 1. | |||
| 5. | Pen VK
PLUS Rifampin** |
25-50 mg/kg/day PO div q 6-8 hrs x 10 days 10 mg/kg PO q 12 hrs (max 600 mg/day) |
500 mg PO q 6 hrs x 10 days 10 mg/kg PO q 12 hrs (max 600 mg/day) |
| **Rifampin should be given on the last four days of penicillin therapy. | |||
Physicians and hospitals should report cases of invasive GAS infection to the local health department as soon as possible. Reporting rules state that such infections should be reported within seven days, but with the current increase reporting immediately by telephone is encouraged.
Hospital laboratories are encouraged to either save isolates of GAS from normally sterile sites or submit these isolates to the Illinois Department of Public Health laboratory, 2121 West Taylor Street, Chicago, Illinois 60612. Future typing of these isolates may be important if future outbreaks or focal clusters are identified.
Sincerely,
Carl W. Langkop, M.S.P.H., Chief
Communicable Disease Control Section