To the Editor:
I was glad to receive the July 1999 issue of Pediatric Annals because I hoped it would answer a few questions regarding the risks of antibiotic resistance. Specifically, does giving a child an antibiotic for 2 days while waiting for the results of cultures add to that risk? The question was not addressed, probably because there are no data, but implicit in the comments made was the suggestion that the longer the antibiotic course, the greater the risk.
The problem is aggravated in the area of strep throat. There is more than enough evidence to show that we cannot diagnose strep throat clinically and thus must depend on laboratory results. At the same time, we know that many children will have positive results on throat cultures, regardless of their health. Dr. Abzug1 recommended that we not culture children with sore throats if they show certain other symptoms (eg, cough or coryza) because we may assume that they do not have streptococcal infections. I fear that Dr. Abzug is in the same position as those older physicians who felt they could confidently diagnose strep throat clinically; why is Dr. Abzug confident that he can diagnose not-strep clinically? I wish I could feel that confident, but I have not seen any published data on sensitive and specific criteria for diagnosing not-strep.
1. Abzug MJ. Meeting the challenge of antibiotic resistance: an evidence-based approach. Pediatr Ann. 1999;28:460-467.
Randal L. Whitman, MD, PhD
Albert Einstein Medical Center
Dr. Abzug's response:
I appreciate Dr. Whitman's insightful questions about the relationship between antibiotic use and resistance and strategies to reduce antibiotic exposure.
Available data suggest that prolonged antibiotic exposure confers greater risk of selection of resistant flora. At the other extreme, it is harder to answer how much risk very short exposures confer. Emergence of resistance has been demonstrated with 1- to 2- week courses of antibiotics, and, in a number of series, receipt of a recent course of antibiotics has been associated with isolation of resistant bacteria. Does this experience apply to 2 days of empiric antibiotic therapy pending results of a throat culture? We do not have a definitive answer to this question, although it is a logical premise that decreasing cumulative exposure to antibiotics (both in a child and in a population) may have an impact on the prevalence of resistant flora.
Dr. Whitman reminds us of the limitations of clinical diagnosis of streptococcal pharyngitis. Numerous studies have demonstrated the inaccuracy of clinical examination, particularly indicating that physicians tend to overestimate the probability of group A streptococcus in an inflamed pharynx. In general, clinical scoring tools have done a better job at discerning who does not have strep than in identifying those with strep (ie, a better negative predictive value than positive predictive value) and in suggesting those for whom a throat culture may not be needed.1 Clinical findings against a diagnosis of streptococcal pharyngitis include "the clear rhinorrhea and sneezing of the common cold or hay fever, throat ulceration of herpangina, or the gingival lesions of herpes simplex stomatitis,"2 as well as hoarseness, cough, diarrhea, and conjunctivitis.3
1. Schwartz BS, Marcy SM, Phillips WR, Gerber MA, Dowell SF. Pharyngitis: principles of judicious use of antimicrobial agents. Pediatrics. 1998;101:171-174.
2. Bréese BB. A simple scorecard for the tentative diagnosis of streptococcal pharyngitis. American Journal of Diseases in Children. 1977; 131:514-517.
3. Dajani A, Taubert K, Ferrieri P, Peter G, Schulman S. Treatment of acute streptococcal pharyngitis and prevention of rheumatic fever: a statement for health professionals. Pediatrics. 1995;96:758-764.