Correspondence

Erythromycin-Resistant Group A Streptococci

N Engl J Med 2002; 347:614-615August 22, 2002

Article

To the Editor:

Martin et al. (April 18 issue)1 identified the emergence of a clone of macrolide-resistant group A streptococci among schoolchildren in Pittsburgh. We are concerned that, on the basis of this finding, physicians will unnecessarily choose even broader-spectrum antimicrobial agents for the treatment of pharyngitis caused by group A streptococci.

Our analysis of data collected in the National Ambulatory Medical Care Survey from 1989 to 1999 showed a significant increase in the use by primary care physicians of extended-spectrum macrolides (mostly clarithromycin and azithromycin) for adults with sore throat.2 This increase probably provides the selective pressure necessary for the emergence of clones such as that described by Martin et al. We also noted a low and decreasing rate of penicillin use among patients who received antibiotics: from 22 percent in 1989 to 13 percent in 1999 (P<0.001).

The infrequent use of penicillin is surprising, given that group A streptococci are universally susceptible to penicillin.3 Inappropriate concern about resistance, the desire on the part of both patients and physicians for newer, “stronger” medications, and the active promotion of other antibiotics have probably contributed to the decrease in the use of penicillin.

With the emergence of antimicrobial-resistant bacteria, it is important to encourage the use of narrow-spectrum antimicrobial agents when appropriate. Martin et al. provide yet more evidence that, in the absence of penicillin allergy, the treatment of choice for pharyngitis caused by group A streptococci is still penicillin (or amoxicillin for children). These are effective, inexpensive, well-tolerated antibiotics to which the target pathogen is always susceptible.

Jeffrey A. Linder, M.D., M.P.H.
Brigham and Women's Hospital, Boston, MA 02115
jlinder@partners.org

Randall S. Stafford, M.D., Ph.D.
Stanford Center for Research in Disease Prevention, Palo Alto, CA 94305

3 References

1. 1

   Martin JM, Green M, Barbadora KA, Wald ER. Erythromycin-resistant group A streptococci in schoolchildren in Pittsburgh. N Engl J Med 2002;346:1200-1206
   Full Text | Web of Science | Medline

2. 2

   Linder JA, Stafford RS. Antibiotic treatment of adults with sore throat by community primary care physicians: a national survey, 1989-1999. JAMA 2001;286:1181-1186
   CrossRef | Web of Science | Medline

3. 3

   Bisno AL. Acute pharyngitis. N Engl J Med 2001;344:205-211
   Full Text | Web of Science | Medline

To the Editor:

Martin and colleagues describe an unexpectedly high rate of macrolide resistance among pharyngeal isolates of endemic group A streptococci from asymptomatic and symptomatic children in Pittsburgh during the 2000–2001 respiratory-infection season. This high rate was due to a single emm 6 clone. In the accompanying editorial, Huovinen appropriately recommends nationwide assessment of the prevalence of macrolide-resistant group A streptococci.1

We established the U.S. Streptococcal Pharyngitis Serotype Surveillance Group in 2000 to assess systematically the serotype distribution of pharyngeal group A isolates from children in geographically diverse U.S. sites, in collaboration with the Centers for Disease Control and Prevention.2 We collected 972 pharyngeal isolates from 9 sites during the 2000–2001 season and almost 1000 isolates from 10 sites during the 2001–2002 season. Our preliminary data for the 2000–2001 isolates indicate that the rate of macrolide resistance was approximately 7.4 percent. It is of particular interest that only 6 of 45 emm type 6 strains (13 percent), including 1 of 7 from our site in eastern Pennsylvania, were resistant to macrolides. This suggests that the emm 6 clone identified by Martin et al. had not become disseminated very widely in the United States in 2000–2001. It is important to continue national surveillance for resistance to macrolides (as well as clindamycin) among pharyngeal isolates of group A streptococci and to evaluate the mechanisms of resistance.

Stanford T. Shulman, M.D.
Robert Tanz, M.D.
William Kabat, B.S.
Children's Memorial Hospital, Chicago, IL 60614
sshulman@northwestern.edu

2 References

1. 1

   Huovinen P. Macrolide-resistant group A streptococcus -- now in the United States. N Engl J Med 2002;346:1243-1245
   Full Text | Web of Science | Medline

2. 2

   Shulman ST, Tanz RR, Kabat W, Kabat K, Beall B. Prospective U.S. nationwide pediatric streptococcal pharyngitis serotype surveillance. Pediatr Res 2002;51:277A-277A abstract.
   Web of Science

Author/Editor Response

The authors reply:

To the Editor: The concern of Drs. Linder and Stafford about the use of broad-spectrum antibiotics for the treatment of pharyngitis caused by group A streptococci is completely appropriate. We continue to recommend the use of penicillin or amoxicillin for the treatment of streptococcal pharyngitis. Most patients who have an allergy to penicillin can safely take a first-generation cephalosporin. In the event of a serious penicillin allergy (type I hypersensitivity reaction), the macrolides can be used for susceptible isolates. Clindamycin may be a reasonable alternative, pending the results of antibiotic-sensitivity testing. Broad-spectrum antibiotics are not necessary for treatment, even when the group A streptococcal isolate is resistant to macrolides.

We agree with Shulman et al., as well as with Huovinen, that there is a pressing need to assess the prevalence of macrolide-resistant group A streptococcus in the United States. Preliminary reports from the surveillance study by Shulman et al. indicate a low rate of resistance to the macrolide antibiotics for the 2000–2001 respiratory-infection season. However, the generalizability of these results will depend on when and where the isolates were obtained. High rates of macrolide resistance were observed in our longitudinal study of schoolchildren and in community isolates during the 2001–2002 respiratory-infection season. The resistance emerged only during the latter part of our surveillance. Intermittent sampling may not reveal resistant isolates, which may be present only transiently. The nationwide prevalence of erythromycin-resistant group A streptococcus must be determined by examining representative isolates in multiple areas in the United States during an entire respiratory-infection season.

Judith M. Martin, M.D.
Michael Green, M.D., M.P.H.
Ellen R. Wald, M.D.
University of Pittsburgh School of Medicine, Pittsburgh, PA 15213-2583
judy.martin@chp.edu

Citing Articles (1)

Citing Articles

1. 1

   Michael R Jacobs, Ron Dagan. (2004) Antimicrobial resistance among pediatric respiratory tract infections: clinical challenges. Seminars in Pediatric Infectious Diseases 15:1, 5-20
   CrossRef