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Home , Pharyngitis, Tonsillitis

Group A streptococcal David H. Darrow, MD, DDS,* and E. Stephen Buescher, MD†

The group A is the most common bacterial The group A beta-hemolytic Streptococcus (GABHS) is cause of pharyngitis. Although most cases of streptococcal the most common bacterium associated with pharyngitis pharyngitis are managed by providers, the in children. In the half-century since the advent of an- otolaryngologist is often consulted to assist in the tibiotics, most pharyngeal by GABHS have management of patients with persistent sore , chronic been benign, self-limited, and uncomplicated processes. streptococcal carriage, recurrent streptococcal pharyngitis, or In fact, many patients improve symptomatically without complications of streptococcal . This article reviews any medical intervention whatsoever. However, a small recent advances in diagnosis and management of individual number of affected individuals continue to develop se- episodes of streptococcal pharyngitis, the clinical approach to vere disease such as streptococcal necrotizing fasciitis, the streptococcal carrier, and the role of in the and sequelae such as renal and cardiac complications, management of recurrent pharyngotonsillitis. Curr Opin Otolaryngol following GABHS infection. In addition, there is evi- Head Surg 2002, 10:449–454 © 2002 Lippincott Williams & Wilkins, Inc. dence that early therapy may be useful in the treatment of GABHS. As a result, appropriate diagnosis and treatment of these infections is imperative.

*Departments of Otolaryngology-Head & Neck Surgery and Pediatrics, and Epidemiology †Division of Pediatric Infectious Diseases, Eastern Virginia Medical School, Children’s Hospital of The King’s Daughters, Norfolk, Virginia, USA. The incidence of GABHS pharyngitis has not been es- timated on the basis of population-based data [1]. Nev- Correspondence to David H. Darrow, MD, DDS, Department of Otolaryngology-Head & Neck Surgery, Eastern Virginia Medical School, 825 ertheless, strep throat is well recognized as a common Fairfax Avenue, Norfolk, VA 23507, USA; e-mail: [email protected] disease among children and adolescents. The incidence Current Opinion in Otolaryngology & Head and Neck Surgery 2002, peaks during the winter and spring seasons, and is more 10:449–454 common in cooler, temperate climates. Close interper- Abbreviations sonal contact in schools, military quarters, dormitories, ASO anti-streptolysin O and families with several children appears to be a risk GABHS group A beta-hemolytic Streptococcus factor for the disease. PANDAS pediatric autoimmune neuropsychiatric disorder associated with group A streptococcal infection Transmission of GABHS is believed to occur through ISSN 1068–9508 © 2002 Lippincott Williams & Wilkins, Inc. droplet spread. The risk of contagion most likely de- pends upon the inoculum size and the virulence of the infecting strain. As a result, individuals are most infec- tious early in the course of the disease. The incubation period is usually between 1 and 4 days; however, antibi- otics rapidly suppress the infection and most physicians will allow affected children to return to school 36 to 48 hours after antimicrobial therapy is started. The role of individuals colonized with GABHS in the spread of the disease is uncertain, although data suggest that car- riers rarely spread the disease to close contacts [2]. Avail- able data do not support the notion that the disease may be transmitted by pets [3].

Pathogenesis The streptococci are gram positive, catalase-negative cocci, characterized by their growth in long chains or pairs in culture. These organisms are traditionally classi- fied into 18 groups with letter designations (Lancefield groups) on the basis of the antigenic carbohydrate com- ponent of their cell walls. While the group A beta- hemolytic Streptococcus is isolated from most patients with streptococcal pharyngitis, group C, G, and B strep- 449 450 Pediatric otolaryngology tococci may also occasionally cause this disorder. Unlike bacterial endotoxin. Other agents of significance include GABHS, however, these organisms are not associated exotoxin A, which may be associated with toxic shock with nonsuppurative sequelae. Further subclassification syndrome, and bacteriocins, which destroy other gram- of streptococci is made based on their ability to lyse positive organisms. Spread of infection may be facilitated sheep or horse erythrocytes in culture; the beta- by a variety of enzymes elaborated by GABHS that at- hemolytic strains cause hemolysis associated with a clear tack fibrin and hyaluronic acid. zone surrounding their colonies, while alpha-hemolytic strains cause partial (green) hemolysis and gamma- Clinical features hemolytic strains cause no hemolysis. of GABHS pharyngotonsillitis vary from mild and (30 to 50% of cases) to Infection by GABHS requires adherence of the organism high , nausea and vomiting, and dehydration (10%) to pharyngeal and tonsillar epithelium. Attachment is [8]. The disorder is in onset, usually characterized accomplished by the fimbriae, which are fingerlike pro- by high fever, , , and abdominal jections from the cell wall of the organism. However, pain. The pharyngeal and tonsillar mucosa are typically resident alpha-hemolytic or viridans streptococci may erythematous and occasionally edematous, with compete with GABHS, inhibiting the establishment of present in 50 to 90% of cases. Cervical adenopathy is also infection to some degree [4]. The predilection of common, seen in 30 to 60% of cases. Most patients im- GABHS to affect the and other particular body prove spontaneously in 3 to 5 days, unless , sites has yet to be explained. , or peritonsillar occur secondarily.

The modus operandi of GABHS can include classical sup- Sequelae purative, toxin-mediated, and/or immune-mediated The risk of following GABHS infection mechanisms. The primary determinant of streptococcal of the pharynx is approximately 0.3% in endemic situa- pathogenicity is an antigenically distinct protein known tions, and 3% under epidemic circumstances [8]. A single as the M protein, which is found within the fimbriae. episode of rheumatic fever places an individual at high Using gene sequencing techniques, more than 120 M risk for recurrence following additional episodes of serotypes are now known [5], and it is likely that many GABHS pharyngitis. Acute glomerulonephritis occurs as more exist that are not yet characterized. Numerous se- a sequela in 10 to 15% of those infected with nephrito- rotypes circulate simultaneously within a selected popu- genic strains [8]. In patients who develop these sequelae, lation; in most cases, those associated with pharyngitis there is usually a latent period of 1 to 3 weeks. are different from those associated with impetigo or pyo- derma. Strains causing pharyngitis in one individual may Recently, PANDAS (pediatric autoimmune neuropsy- cause invasive disease when transmitted to other indi- chiatric disorder associated with group A streptococcal viduals [6•]. The M protein of the Streptococcus allows the infection) has been recognized as an immune-mediated organism to resist phagocytosis in the absence of type- illness associated with GABHS infection, similar to specific antibody. In the immunocompetent host, the Sydenham’s chorea. In a recent prospective study iden- synthesis of type-specific anti-M and other antibodies, tifying children with PANDAS, the most common pre- which belong primarily to the IgG class of immunoglob- sentation was the abrupt onset of severe obsessive- ulins, confers long-term serotype-specific to compulsive disorder behaviors including hand washing, the particular strain in question. In laboratory-produced preoccupation with germs, and daytime urinary urgency -resistant strains of GABHS, the M protein is or frequency in the absence of infection [9•]. These be- absent, thereby rendering these strains more vulnerable haviors resolved with treatment of the accompanying to phagocytosis [7]. This finding may help to explain sentinel GABHS pharyngitis. Recurrence of obsessive- why there have been no naturally occurring penicillin- compulsive behaviors were seen in 50% of patients re- resistant GABHS isolated in more than 50 years of peni- infected with GABHS and resolved with antibiotic treat- cillin use. ment. The disorder has recently been reviewed in the otolaryngology literature [10••]. GABHS are capable of elaborating at least 20 extracel- lular substances that affect host tissue; the interested Diagnosis reader may find a complete discussion of these sub- Early diagnosis of streptococcal pharyngitis has been a stances elsewhere. Among the most important are strep- priority in management of the disease, primarily due to tolysin O, an oxygen-labile hemolysin, and streptolysin the risk of renal and cardiac sequelae. A number of au- S, an oxygen-stable hemolysin, which lyse erythrocytes thors have studied the predictive value of various com- and damage other cells such as myocardial cells. Strep- binations of signs and symptoms in an effort to distin- tolysin O is antigenic, while streptolysin S is not. guish streptococcal from nonstreptococcal pharyngitis; GABHS also produce three erythrogenic or pyrogenic however, none of these has been particularly reliable. toxins (A, B, and C) whose activity is similar to that of Taken together, these studies demonstrate a false nega- Streptococcal pharyngitis Darrow and Buescher 451 tive rate of about 50% and a false positive rate of 75% tion in ASO titer is not necessarily indicative of ongoing [11]. Adenopathy, fever, and pharyngeal exudate have clinical disease. A positive test is defined as a twofold the highest predictive value for a positive culture and dilution increase in titer between acute and convalescent rise in anti-streptolysin O (ASO) titer, and absence of serum, or any single value above 333 Todd units in chil- these findings in the presence of , , dren. Response to treatment does not predict a rise in hoarseness, or conjunctivitis most reliably predicts a antibody titer [11]. Results should be interpreted with negative culture, or positive culture without rise in caution, since streptolysin O is also elaborated by group ASO [11]. C and G streptococci, ASO titers vary with age, and some interfere with the ASO response [16]. Tests Although the cost effectiveness of has for anti-DNAse B and other extracellular antibodies may been questioned [12], most clinicians still advocate this be useful in patients with suspected sequelae of GABHS procedure as the gold standard to determine appropriate infection who do not demonstrate a rise in ASO [16•]. treatment for GABHS. The , tonsillar crypts, or posterior pharyngeal wall must be swabbed for greatest The carrier state accuracy. Material obtained by throat swab is placed on a Patients who have been exposed to GABHS may con- plate containing 5% sheep’s blood agar and a bacitracin tinue to carry the organism asymptomatically even after disk. Inhibition of bacterial growth is approximately 95% adequate antimicrobial therapy. Carriers are recognized accurate for identification of GABHS. The decision as those individuals who demonstrate a positive culture about whether to treat pending culture results or to delay for the organism but no rise in ASO convalescent titer. treatment until the results are available remains contro- This condition is not associated with particular subtypes versial, although some studies suggest that early treat- of the organism or any specific pharyngeal conditions. ment hastens the clinical response to antibiotics [13]. Carriage rates cited in the literature vary from 3 to 40%, depending on the population studied [17]; however, this In the mid-1980s, tests for rapid detection of the group- figure may be overestimated because of the use of anti- specific carbohydrate became available. Such assays, biotics, which interfere with the rise in ASO titer. Car- which include enzyme immunoassays, latex agglutina- riers appear to be at little risk to transmit GABHS, or to tion tests, and optical immunoassays have simplified the develop sequelae of the disease. James et al. [18] dem- decision to treat at the time of the office visit, and have onstrated infection of family members by carriers only eliminated the need for additional postvisit communica- 9% of the time, and only 40% of those infected devel- tion. However, while most investigators report a speci- oped clinical disease. Thus, only 3.5% of carriers produce ficity of greater than 90% for these tests, recent data clinical disease within their family. It is unknown wheth- suggest a false-positive rate as high as 15% [14]. In ad- er carriers are at increased risk of recurrent pharyngitis. dition, their sensitivity is generally in the 60 to 90% range, depending on the clinical environment (eg, highly The high rate of streptococcal carriage complicates the organized clinical trials vs hospital clinical laboratories) distinction between bacterial and viral pharyngitis in the and varying with the spectrum of disease (higher clinical patient with sore throat and a positive culture. The suspicion correlates with greater sensitivity) [15•]. As a American Academy of Pediatrics [19] and the Infectious result, many clinicians advocate throat culture for chil- Disease Society of America [20] currently recommend dren with suspected streptococcal disease and negative that testing for GABHS should not be performed in chil- rapid strep tests. Rapid antigen detection is usually more dren with conjunctivitis, cough, hoarseness, coryza, diar- expensive than throat culture, and this technique must rhea, oral ulcerations, or other clinical manifestations still be interpreted with care given the high incidence of highly suggestive of viral infection. A similar approach posttreatment carriers. Studies also suggest a learning has recently been suggested for adults with suspected curve effect associated with this diagnostic modality. It GABHS infection, requiring the presence of two Cen- should be noted that rapid streptococcal antigen tests tor criteria (history of fever, absence of cough, swol- were developed for use in the diagnosis of GABHS pha- len/tender anterior cervical nodes, tonsillar exudate) ryngotonsillitis; their application as diagnostic tests for prior to consideration of GABHS testing [21]. When GABHS at nonpharyngeal sites is not a Food and Drug GABHS infection must be distinguished from nonstrep- Administration–approved use of these tests, although tococcal disease in a carrier, a convalescent ASO titer some authors advocate this practice. should be considered. Serologic tests are recognized as the definitive means for diagnosing acute streptococcal infection. A rise in ASO Treatment of the asymptomatic carrier is desirable in the titer is usually demonstrable within 1 week of infection following situations. and peaks at 3 to 6 weeks. The subsequent decline usu- ally occurs within 6 to 8 weeks but is less reliable and • Carriers in families with a history of rheumatic fever may not occur for months; therefore, a persistent eleva- • Carriers with a history of acute glomerulonephritis 452 Pediatric otolaryngology

• Carriers in families experiencing ping-pong spread of cillin G were bacteriologic treatment failures [26••]. disease Such data support consideration of revised dosing regi- • Carriers in schools experiencing GABHS epidemics mens or alternative antimicrobials in the management of • Carriers who are food handlers GABHS. However, while and • Carriers who are hospital workers are active against GABHS and their use as treatment for GABHS pharyngitis is considered an acceptable alterna- tive to penicillin, their ability to prevent rheumatic fever In such cases, additional antibiotics, especially clindamy- remains unproven. cin and rifampin, have demonstrated some efficacy. In refractory cases, tonsillectomy should be considered. has traditionally been the drug of choice for patients with penicillin ; however, increasing Treatment prevalence of -resistant GABHS throughout Although most upper respiratory infections by GABHS the world is changing this paradigm. Among pharyngeal resolve in 3 to 5 days without treatment, studies suggest cultures from Pittsburgh school children, clonal erythro- that antimicrobial therapy prevents suppurative and non- mycin-resistant GABHS was found in 48% [27•]. As has suppurative sequelae including rheumatic fever, and been described in other studies, the unexpectedly high may also hasten clinical improvement [13,22]. Treatment resistance rate was associated with increased local pre- is therefore indicated for all patients with positive rapid scribing of macrolide antibiotics during the same period. tests for the group A antigen. When testing is negative, it , used as a 5-day therapy by many clinicians is acceptable practice to treat for a few days while formal for patients expected to be poorly compliant, may simi- throat cultures are incubating, providing such treatment larly be associated with increasing resistance. is discontinued in the event that final cultures are also negative. When testing is not available, it has been sug- Most patients with positive cultures following treatment gested that the presence of all four may are GABHS carriers; these individuals need not be re- be considered an indication for initiation of therapy [21]. treated if their symptoms have resolved. Other explana- Given the low sensitivity of rapid strep testing, a decision tions for microbiologic failures, including the presence of not to treat based on a negative test may not be the best beta-lactamase producing organisms in the respiratory choice. tract, the presence of GABHS tolerant to penicillin, and the production of inhibitory substances by organisms in GABHS is sensitive to a number of antibiotics; however, the upper that promote persistence of clinical experts consider penicillin the drug of choice in GABHS, have not been convincingly demonstrated nearly all cases [19,20]. To date, no strains of GABHS [28•,29]. For patients in whom complete bacteriologic acquired in vivo have demonstrated penicillin resistance clearance is desirable, such as those with a family mem- in vitro. In addition, a 1993 meta-analysis found no in- ber with a history of rheumatic fever, a course of clinda- crease in the bacteriologic failure rate with penicillin dur- mycin or a second course of penicillin combined with ing the last 40 years [23]. Depot benzathine penicillin G rifampin may yield increased success. In patients with is still advocated by the American Heart Association for recurrent symptoms, serotyping may aid in distinguish- primary treatment of GABHS pharyngitis; however, a ing bacterial persistence from recurrence. There are no 10-day course of penicillin orally is the most widely pre- data available regarding the use of antibiotic prophylaxis scribed regimen. Twice-daily dosing by the oral route in these patients, and in such cases tonsillectomy may be yields results similar to those obtained with four times a most advantageous. day dosing [24]. A once-daily oral dose of for 10 days also has demonstrated bacteriological efficacy During antimicrobial therapy, patients must be moni- similar to that of oral penicillin dosed three times a day tored carefully for fluid intake, pain control, and impend- for 10 days [25]. Courses of shorter duration are associ- ing suppurative complications such as peritonsillar ab- ated with bacteriologic relapse and are less efficacious in scess. Small children may become dehydrated rapidly, the prevention of rheumatic fever. and may require hospitalization for administration of flu- ids intravenously. During the 1980s, several authors reported a decrease in bacteriologic control rates, attributed primarily to inocu- Removal of the tonsils as prevention against infection lum effects and to increased tolerance to penicillin. Re- has been a popular concept for decades. Although a num- lapses and persistent positive cultures were not associ- ber of clinical trials from the early 1900s suggested effi- ated with significant symptoms or with suppurative or cacy of tonsillectomy in reduction of recurrent throat in- nonsuppurative sequelae, but the goal of eradication to fection, most were of questionable validity due to prevent rheumatic fever was not achieved. In a recent nonrandom selection of operated subjects, reliance on study, 35% of 284 patients treated with oral penicillin V parents for postoperative data collection, and inappropri- and 37% of 271 patients treated with benzathine peni- ate statistical analysis. A series of trials by Paradise et al. Streptococcal pharyngitis Darrow and Buescher 453 at the University of Pittsburgh in the 1970s and 1980s for adenoidectomy. Those without such indications (N = sought to avoid these methodological flaws. 177) were assigned to the first trial and randomized to undergo tonsillectomy, adenotonsillectomy, or no sur- The first two trials [30] were parallel studies with iden- gery. Patients with indications for adenoidectomy (N = tical design, except that assignment to surgical or non- 151) were assigned to the second trial and underwent surgical treatment was random in one and according to adenotonsillectomy or no surgery. In both trials, the fre- parental preference in the other. Throat infection was quency of infection in both the surgical and nonsurgical defined to include one of the following features: tem- groups again dropped, although the decrease was mar- perature greater than 38.3°C, tender cervical adenopathy ginally greater (approximately one episode per year) in or nodes greater than 2 cm in size, tonsillar exudate, or the surgical groups. However, control subjects in both positive culture for GABHS. No other attempt was made trials again developed far less than one episode of mod- to determine the cause of the infection. Patients were erate or severe pharyngitis per year. Although the data entered into the study only if they had physician docu- were not dramatically different from those in the initial mentation of seven episodes in 1 year, five episodes a publication, in this study, the authors concluded that the year for 2 years, or three episodes a year for 3 years. small potential benefits of surgery did not justify the associated risk and expense. Furthermore, performing Ninety-one patients completed the randomized trial and adenoidectomy in addition to tonsillectomy conferred no 96 completed the nonrandom trial. Tonsillectomized pa- additional advantage in controlling throat infections tients in the trial with random assignment had 1.85, 1.05, when compared with tonsillectomy alone. and 0.43 fewer episodes of throat infection than control patients for each of the first three postoperative years, There are currently no clinical trials to support or refute respectively, while those in the parallel nonrandom trial the efficacy of tonsillectomy for streptococcal carriers had 1.32, 1.32, and 1.58 fewer episodes; these differences with or without chronic sore throat. were statistically significant in the first 2 years. However, in both trials, most patients in the nontonsillectomized References and recommended reading group were enrolled on the basis of three episodes per Papers of particular interest, published within the annual period of review, year, while most tonsillectomized patients were in the have been highlighted as: • Of special interest five or seven episodes per year groups. As a result, it is •• Of outstanding interest difficult to conclude that the lower postoperative fre- 1 Markowitz M: Changing epidemiology of group A streptococcal infections. quency of infection in the tonsillectomy group is due to Pediatr Infect Dis J 1994, 13:557–560. the surgical intervention rather than to spontaneous im- 2 Kaplan EL: The group A streptococcal upper respiratory tract carrier state: an provement of patients affected for a shorter period. Fur- enigma. J Pediatr 1980, 97:337–345. thermore, moderate and severe episodes were rare even 3 Wilson KS, Maroney SA, Gander RM: The family pet as an unlikely source of in the control groups, and there was no statistical differ- group A beta-hemolytic streptococcal infection in humans. Pediatr Infect Dis ence in total days spent with sore throat between the J 1995, 14:372–375. surgical and nonsurgical groups. On the other hand, the 4 Fujimori I, Kikushima K, Hisamatsu K, et al.: Interaction between oral alpha- streptococci and group A streptococci in patients with . Ann Otol effect of tonsillectomy may have been understated due Rhinol Laryngol 1997, 106:571–574. to transfer of severely affected patients from the nonsur- 5 Facklam RF, Martin DR, Lovgren M, et al.: Extension of the Lancefield classi- gical to the surgical groups. fication for group A streptococci by addition of 22 new M protein gene se- quence types from clinical isolates: emm103 to emm124. Clin Infect Dis 2002, 34:28–38. Based on these studies, tonsillectomy may offer a small 6 Haukness HA, Tanz RR, Thomson RB Jr, et al.: The heterogeneity of endemic advantage in the treatment of children in whom a pattern • community pediatric group A streptococcal pharyngeal isolates and their re- of severe recurrent pharyngotonsillitis has been well lationship to invasive isolates. J Infect Dis 2002, 185:915–920. This study suggests that children with pharyngitis may represent a reservoir for documented. The authors themselves state, however, GABHS strains with invasive potential. that a decision whether or not to perform tonsillectomy 7 Gerber MA: Antibiotic resistance: relationship to persistence of group A should consider risks, preferences, and anxieties of par- streptococci in the upper respiratory tract. Pediatrics 1996, 97:971–975. ent and child, school absences due to illness, accessibility 8 Kaplan EL, Gerber MA: Group A, group C, and group G beta-hemolytic strep- to services, cost, and availability of surgical tococcal infections. In Textbook of Pediatric Infectious Diseases, 4th edition. Edited by Feigin RD, Cherry JD. Philadelphia: WB Saunders; 1998:1076– facilities. 1088.

9 Murphy ML, Pichichero ME: Prospective identification and treatment of chil- In a study published recently [31••], Paradise et al. re- • dren with pediatric autoimmune neuropsychiatric disorder associated with port the results of two trials in which the entrance criteria group A streptococcal infection (PANDAS). Arch Pediatr Adolesc Med 2002, 156:356–361. from the first two studies were made less stringent. Pa- This is the first prospective study of the association between PANDAS and tients entering the study had a lower frequency of infec- GABHS pharyngitis and the response to antimicrobial therapy. tion or less severe episodes, or lacked the documentation 10 Orvidas LJ, Slattery MJ: Pediatric autoimmune neuropsychiatric disorders and •• streptococcal infections: role of the otolaryngologist. Laryngoscope 2001, of episodes required in the first study. These patients 111:1515–1519. were grouped together and then assessed for indications This paper is an excellent review of PANDAS for the otolaryngologist. 454 Pediatric otolaryngology

11 Kline JA, Runge JW: Streptococcal pharyngitis: a review of pathophysiology, of immediate treatment of group A beta-hemolytic streptococcal pharyngitis diagnosis, and management. J Emerg Med 1994, 12:665–680. with penicillin. Pediatr Infect Dis J 1987, 6:635–643. 12 Tompkins RK, Burnes DC, Cable WE: An analysis of the cost-effectiveness of 23 Markowitz M, Gerber MA, Kaplan EL: Treatment of streptococcal pharyngo- pharyngitis management and acute rheumatic fever prevention. Ann Intern tonsillitis: reports of penicillin’s demise are premature. J Pediatr 1993, Med 1977, 86:481–492. 123:679–685. 13 Randolph MF, Gerber MA, DeMeo KK, et al.: Effect of antibiotic therapy on the 24 Gerber MA, Spadaccini LJ, Wright LL, et al.: Twice-daily penicillin in the treat- clinical course of streptococcal pharyngitis. J Pediatr 1985, 106:870–875. ment of streptococcal pharyngitis. Am J Dis Child, 1985, 139:1145–1148. 14 Johnson DR, Kaplan EL: False-positive rapid antigen detection test results: 25 Feder HM Jr, Gerber MA, Randolph MF, et al.: Once-daily therapy for strep- reduced specificity in the absence of group A streptococci in the upper re- tococcal pharyngitis with amoxicillin. Pediatrics 1999, 103:47–51. spiratory tract. J Infect Dis 2001, 183:1135–1137. 26 Kaplan EL, Johnson DR. Unexplained reduced microbiological efficacy of in- 15 DiMatteo LA, Lowenstein SR, Brimhall B, et al.: The relationship between the •• tramuscular benzathine penicillin G and of oral penicillin V in eradication of • clinical features of pharyngitis and the sensitivity of a rapid antigen test: evi- group A streptococci from children with acute pharyngitis. Pediatrics 2001, dence of spectrum bias. Ann Emerg Med 2001, 38:648–652. 108:1180–1186. This study suggests that sensitivity of rapid antigen testing varies with clinical se- This important study reports the persistence of GABHS in more than 35% of pa- verity, and that in patients with three or four clinical criteria for GABHS, culture tients prescribed penicillin, suggesting a possible role for adjustment of dosing or confirmation of negative rapid strep tests may not be necessary. alternative antimicrobials therapy. 16 Shet A, Kaplan EL: Clinical use and interpretation of group A streptococcal 27 Martin JM, Green ML, Barbadora KA, et al.: Erythromycin-resistant group A • antibody tests: a practical approach for the pediatrician or primary care phy- • streptococci in children in Pittsburgh. N Engl J Med 2002, 346:1200–1206. sician. Pediatr Infect Dis J 2002, 21:420–430. This study reports the emergence of erythromycin-resistant strains of GABHS, The authors review use and interpretation of ASO, anti-DNAse, and other antibody which may impact the choice of antimicrobial therapy for GABHS in patient with tests for GABHS infection. penicillin allergy. 17 Pichichero ME, Marsocci SM, Murphy ML, et al.: Incidence of streptococcal 28 Gerber MA, Tanz RR, Kabat W, et al.: Potential mechanisms for failure to carriers in private pediatric practice. Arch Pediatr Adolesc Med 1999, eradicate group A streptococci from the pharynx. Pediatrics 1999, 104:911– 153:624–628. 917. 29 Brook I: Failure of penicillin to eradicate group A beta-hemolytic streptococ- 18 James WE, Badger GF, Dingle JH: A study of illnesses in a group of Cleveland cal tonsillitis: causes and management. J Otolaryngol 2001, 30:324–329. families, XIX: The epidemiology of the acquisition of group A streptococci and • The author provides an excellent summary of mechanisms of penicillin failure in of associated illness. N Engl J Med 1960, 262:687–694. GABHS infection. 19 American Academy of Pediatrics: Group A streptococcal infections. In 2000 30 Paradise JL, Bluestone CD, Bachman RZ, et al.: Efficacy of tonsillectomy for Redbook—Report of the Committee on Infectious Diseases, 25th ed. Edited recurrent throat infection in severely affected children. N Engl J Med 1984, by Pickering LK. Elk Grove Village, IL: American Academy of Pediatrics; 310:674–683. 2000:526–536. 31 Paradise JL, Bluestone CD, Colborn DK, et al.: Tonsillectomy and adenoton- 20 Bisno AL, Gerber MA, Gwaltney JM Jr, et al.: Diagnosis and management of •• sillectomy for recurrent throat infection in moderately affected children. Pedi- group A streptococcal pharyngitis: a practice guideline. Clin Infect Dis 1997, atrics 2002, 110:7–15. 25:574–583. This study presents two trials in which the authors relax the stringent entrance 21 Cooper RJ, Hoffman JR, Bartlett JG, et al.: Principles of appropriate antibiotic criteria used in their 1984 paper. The results suggest that in less severely affected use for acute pharyngitis in adults: background. Ann Intern Med 2001, patients with recurrent pharyngitis, tonsillectomy confers marginal benefit, and that 134:509–517. the small advantages of the procedure may not justify the inherent risk or cost. The authors also demonstrated no additional efficacy when adenoidectomy was per- 22 Pichichero ME, Disney FA, Talpey WB, et al.: Adverse and beneficial effects formed with tonsillectomy.