Use of Available Dosage Forms of Cephalexin in Clinical Comparison with Phenoxymethyl Penicillin and Benzathine Penicillin in the Treatment of Streptococcal Pharyngitis in Children

The effectiveness of cephalexin, an oral cephalosporin using a dosage equivalent to available capsular dosage forms, was studied in relation to the effectiveness of phenoxymethyl penicillin and benzathine penicillin in the treatment of 128 patients with beta-hemolytic streptococcal pharyngitis, all but six of whom had group A streptococci isolated from throat cultures. Approximately one-half, 66 patients, received cephalexin for 10 days; 34 patients received phenoxymethyl penicillin for 10 days; and 28 patients had a single injection of benzathine penicillin. There were four treatment failures determined bacteriologically post-therapy, two in the cephalexin treatment group and one each in the oral penicillin and intramuscular penicillin groups. Similar cure rates of 96.7, 97.1, and 96.4% were computed for the respective treatment regimens. Whereas intramuscular benzathine penicillin remains the regimen of choice in most instances, cephalexin appeared to be as effective as oral penicillin in the elimination of group A streptococci from the pharynx when oral treatment was desired for streptococcal pharyngitis.     

Beta-hemolytic streptococcal pharyngitis: uncommon in infectious mononucleosis

Infectious mononucleosis (IM) and beta-hemolytic streptococcal pharyngitis may present similar clinical pictures and may occur concurrently; however, recent studies have differed sharply with older ones that cited high rates of concurrent disease. Our study of 100 consecutive new patients meeting strict criteria for a diagnosis of IM found only 4% with positive throat cultures for group A beta-hemolytic streptococci at the time of diagnosis. Use of antibiotics for presumed streptococcal pharyngitis in patients with IM is unjustified. Only patients with positive cultures should be treated.     

Protective Study with a Group A Streptococcal M Protein Vaccine. INFECTIVITY CHALLENGE OF HUMAN VOLUNTEERS

Healthy adult male volunteers were immunized with purified M protein from Group A streptococci. Type 1. The vaccine was administered subcutaneously as an aluminum hydroxide-precipitated antigen in three montly doses. Control subjects received a placebo of the aluminum hydroxide adjuvant. To test the efficacy of the immunization, vaccinees and controls were challenged with a virulent strain of Type 1 streptococci applied to the pharynx. The immunization and challenge of the vaccinated and control subjects (19 men in each group) were carried out as a double blind experiment. All subjects were carefully screened by physical and laboratory examinations before and after the immunization and infectivity schedules. 30-50 days after the last injection, the vaccinees and control subjects were infected with the streptococci. Careful surveillance was maintained to evaluate the extent of acquired streptococcal infection. Throat cultures, leukocytes counts, temperatures, and physical signs and symptoms were monitored daily. All subjects received 1.2 million U of penicillin intramuscularly no later than 6 days after inoculation with the culture. Illness was judged by the appearance of exudative pharyngitis and cervical adenopathy accompanied by a positive throat culture. By these criteria, 9 of the 19 placebo controls, and 1 of 19 vaccinees were ill. No residual illness or clinical complications was observed after the penicillin treatment. It is concluded that the alum-precipitated M protein vaccine afforded protection against an upper respiratory Type 1 streptococcal infection.     

How reliable and useful is the latex agglutination test in diagnosing streptococcal throat infection in general practice?

A rapid latex agglutination test for diagnosing streptococcal pharyngitis in general practice was evaluated on 226 patients with acute throat infection. The test had a sensitivity of 96% and a specificity of 91% regarding group A beta hemolytic streptococci. The test was fairly simple to perform and the result was available before the patient left the office. The test was supplied as a self-contained kit, was safe to handle and economically acceptable. Even through this test is not a reliable as the traditional microbiological culture, it represents a significant practical and clinical improvement in the daily management of patients with acute throat infections.     

Lack of correlation between streptococcal Fc receptors and symptomatic pharyngitis

To determine whether bacterial Fc(gamma) surface receptors are associated with symptomatic streptococcal pharyngitis, throat cultures were obtained from 264 children (grouped according to symptoms of pharyngeal infection) and from 328 who were asymptomatic. Group A beta-hemolytic streptococci which were recovered were tested for the presence of Fc(gamma) surface receptors. There were no statistically significant differences in the incidence of Fc(gamma) surface receptors on strains from the various patient groups.     

Validation and modification of streptococcal pharyngitis clinical prediction rules

OBJECTIVE: To validate a simplified version of the Walsh clinical prediction rules (CPRs) for the presence of streptococcal pharyngitis in an inner-city, ethnically diverse population. PATIENTS AND METHODS: This prospective study conducted in New York City, NY, from January 1,1997, to May 31,1997, consisted of 171 consecutive adult walk-in patients who presented with symptoms of upper respiratory tract infection and/or sore throat. The patients were assessed by using 5 clinical factors: cough, exposure to known streptococcal contact, temperature, tonsillar-pharyngeal exudates, and cervical lymphadenopathy. Throat cultures for group A beta-hemolytic streptococcus were obtained from all patients. Clinicians assessing the patients were unaware of throat culture results, and those processing the throat cultures were blinded to the clinical predictors. RESULTS: The prevalence of streptococcal pharyngitis was 24% (95% confidence interval, 18%-30%). The simplified version of the Walsh CPR for streptococcal pharyngitis predicted accurately the probability of a positive culture in our diverse population (area under the receiver operating characteristic curve, 0.71). The simplified CPR also showed clinically useful likelihood ratios and posterior probabilities. CONCLUSION: A simplified version of the Walsh CPR is accurate for diagnosing streptococcal pharyngitis in an inner-city population. This finding should provide clinicians more confidence in applying the CPR in similar clinical settings.     

Penicillin V therapy for streptococcal pharyngitis: comparison of dosage schedules.

Two dosage regimens of penicillin V were compared in 327 patients with mild to moderately severe streptococcal pharyngitis. Patients fulfilling study criteria were randomly assigned to a b.i.d. or a t.i.d. dosage schedule. Those in the b.i.d. group were given 500 mg twice daily; those in the t.i.d. group were given 250 mg three times daily. Duration of therapy was ten days for both groups. Cure was based on prompt symptomatic improvement, subsidence of clinical signs, and negative throat cultures for group A beta-hemolytic streptococci. Both dosage schedules yielded similar cure rates, indicating that with penicillin V, a b.i.d. regimen is as effective as a t.i.d. regimen in treating streptococcal pharyngitis.     

Throat culture or rapid strep test?

Clearly, rapid tests for streptococci identification are here to stay, and development of the technology is likely to continue. The most rational use of these tests is to identify streptococcal pharyngitis when patients have severe symptoms or when special situations warrant early detection. Throat culture alone is sufficient for most other patients, and all negative rapid tests should be confirmed by throat culture. Specific antistreptococcal therapy should be initiated if either the rapid test or culture is positive. If the physician decides on the basis of clinical criteria to treat pharyngitis with an antibiotic that covers group A beta-hemolytic streptococci, a rapid test is not necessary. If confirmation of the infection is warranted in these cases, throat culture alone should suffice. No rapid strep test kit clearly outperforms others. With any test, good results depend on the quality of the specimen.     

The clinical pattern of group C streptococcal pharyngitis in children

Group A streptococcal pharyngitis of is a common infectious disease with a well-recognized clinical pattern, as opposed to that attributed to group C assault. The aim of this study was to identify the clinical features of group C streptococcal pharyngitis in children. In total, 144 children participated in the study, consisting of three distinct categories. Group I patients consisted of children with group A streptococcal pharyngitis, group II patients included children with group C streptococcal pharyngitis,, while children with pharyngitis with no isolated causative agent constituted group III patients. With the exception of sore throat, which was three times more common in group I patients compared to group II patients, there were no other differences in symptoms and signs between these two groups. Similarly, no difference was found between group II patients and group III patients with respect to clinical features. Two or more Centor criteria were found in 77% of the children with group C streptococcal pharyngitis and in 89% of the children with group A streptococcal pharyngitis. It is concluded that the clinical features of group C streptococcal pharyngitis are similar to but milder than those of group A streptococcal pharyngitis.     

Perianal streptococcal dermatitis. The possible protective role of alpha-streptococci against spread and recurrence of group A streptococcal throat infection

OBJECTIVE: To follow the spread of beta-haemolytic streptococci group A (GAS) within a family and examine the protective activity of normally occurring alpha-streptococci against GAS tonsillitis. DESIGN: Follow up of recurrent GAS throat infection within a family. SETTING: Intra familial spread of GAS. PATIENTS: A family of four, the mother suffering from recurrent streptococcal tonsillitis and a son with perianal streptococcal dermatitis. RESULTS: The strain of the GAS found in the perianal region of the boy was identical with that found in the throat of his mother. She had recurrent streptococcal tonsillitis, while the boy remained healthy in the throat. She lacked interfering alpha-streptococci in the throat, while the boy had a massive growth of alpha-streptococci in his throat with capacity to inhibit the growth of the streptococcal isolate. MAIN OUTCOME MEASURES: Infection with GAS within a family correlated with the growth-inhibiting activity of the alpha-streptococci in vitro. CONCLUSIONS: The study demonstrated the spread of GAS from a patient with streptococcal dermatitis to the throat of another person within the family, and the hindrance of induction of infection in patients carrying interfering alpha-streptococci.     

Resurgence of rheumatic fever in the United States. The changing picture of a preventable illness.

The recent resurgence of rheumatic fever reported in eight locations in the United States after years of decline has several noteworthy characteristics. Most patients were children of families in high- to middle-income brackets with ready access to medical care. In four of the outbreaks, the majority of patients were adults, who were more likely than children to have arthritis and less likely to have Sydenham's chorea. Many patients had no clinical history of streptococcal pharyngitis. Rheumatic fever developed in some patients despite antibiotic treatment for streptococcal pharyngitis. Analysis of the outbreaks supports the following conclusions: No population is exempt from rheumatic fever. Physicians should be diligent in performing throat cultures in cases of suspected streptococcal pharyngitis. The efficacy of orally administered penicillin in preventing rheumatic fever should be reexamined, and oral antibiotics that are potentially more effective should be sought.     

Streptococcal pharyngitis. What's new

Group A beta-hemolytic streptococcal pharyngitis continues to be a major problem and accounts for a large number of physician visits. The recent resurgence of acute rheumatic fever in several areas in the United States underlines the need to accurately diagnose and correctly treat streptococcal pharyngitis. Appropriate treatment with antibiotics effectively prevents rheumatic fever. Early institution of treatment also leads to prompt alleviation of symptoms. The "gold standard" for diagnosing group A streptococcal pharyngitis is the throat culture. Newer rapid diagnostic tests may be used, but the clinician must recognize that there are a substantial number of false-negative tests (low sensitivity). Therefore, patients with negative rapid tests should have standard throat cultures as well. Patients with positive rapid tests should be treated with appropriate antibiotics, as should patients with positive throat cultures. Patients with signs and symptoms that are highly suggestive of streptococcal pharyngitis can also be treated, pending throat culture results. Penicillin continues to be the drug of choice for treatment, and American Heart Association guidelines suggest the use of oral penicillin V for ten days or intramuscular benzathine penicillin G. Alternative antibiotics commonly used include erythromycin and various cephalosporins. Throat cultures need not be obtained from most patients after therapy. However, some patients may seem to be having frequent streptococcal infections or may be recognized as asymptomatic carriers. Carriers may be considered for therapy with intramuscular benzathine penicillin G plus oral rifampin.     

Prevalence of non-group-A beta-hemolytic streptococci in childhood pharyngitis

We studied the prevalence of non-group-A beta-hemolytic streptococci (NGAS) in the pharyngeal cultures of symptomatic and asymptomatic children. Throat cultures were obtained by house officers in the Emergency Department at Children's Hospital of Pittsburgh to aid in the evaluation of children with symptoms or signs of pharyngitis, or both. A total of 929 throat cultures were read in four discrete periods between July 1982 and February 1984. A control group was composed of 414 asymptomatic children, recruited contemporaneously with study subjects. beta-Hemolytic colonies were evaluated for bacitracin susceptibility and grouped by the Streptex method. The prevalences of NGAS in symptomatic and control children were 6.5% (60/929) and 1.0% (4/414), respectively (P less than .01). Seasonal variation in the recovery of NGAS from symptomatic children was suggested by higher relative and absolute recovery rates of NGAS during warm weather. This study demonstrates an association between NGAS and sporadic pharyngitis in school children but does not establish causality.     

Performance of the tandem ICON strep A® enzyme immunoassay system for detection of group a streptococci from oropharyngeal swabs

The Tandem ICON Strep A® (TISA Hybri-tech, Inc.) was compared to culture for detection of group A streptococci, using throat swabs obtained from patients with symptoms of pharyngitis. Each swab was first inoculated to a 5% sheep blood agar plate and then tested for streptococcal antigen using the TISA. Cultures were incubated anaerobically at 35°C for 36 to 48 hours unless positive following overnight incubation. Group A streptococci were recovered in culture and serologically identified from 163 (21.0%) of the 776 swabs processed. The sensitivity and specificity of the TISA were 76.7% and 96.4%, respectively, whereas the predictive values of positive (PVP) and negative (PVN) results were 85.0% and 94.0%, respectively. However, TISA specificity ranged from 93.6% in one of 3 lots tested to 99.1% in another (P < 0.005). The PVP of the former lot was 76.3%, whereas that of the latter was 95.6% (P < 0.005). The relative lack of sensitivity and lot-to-lot variation observed with the TISA in this study indicate that the product is not a suitable alternative to a competently performed throat culture.     

Clinical assessment of pharyngitis in general practice

The present study investigates the feasibility of the clinical differentiation between patients with beta-haemolytic streptococcal pharyngitis from those with pharyngitis caused by other agents, based on the patients' symptoms, symptom duration, and the clinical findings. Twenty-four general practitioners recruited 225 patients for the study. Fifty-six patients had positive and 169 patients negative group A beta-haemolytic streptococcal throat cultures. Twenty-two patients in the streptococcal group and 76 patients in the non-streptococcal group were initially correctly diagnosed based on an overall clinical assessment (sensitivity 0.39, specificity 0.55 and accuracy 0.51). This is as accurate as "flipping a coin". Similar figures were found with regard to the individual symptoms (accuracy 0.38-0.68) and clinical findings (accuracy 0.36-0.65). Taking the duration of symptoms into account and applying discriminant function analysis did not significantly improve these figures. In order to obtain a sufficiently accurate diagnosis in general practice, the use of the new rapid agglutination test for streptococcal identification is recommended.     

Pharyngitis

Sore throat is one of the most common reasons for visits to family physicians. While most patients with sore throat have an infectious cause (pharyngitis), fewer than 20 percent have a clear indication for antibiotic therapy (i.e., group A beta-hemolytic streptococcal infection). Useful, well-validated clinical decision rules are available to help family physicians care for patients who present with pharyngitis. Because of recent improvements in rapid streptococcal antigen tests, throat culture can be reserved for patients whose symptoms do not improve over time or who do not respond to antibiotics.     

Impact of identification of Streptococcus dysgalactiae subspecies equisimilis from throat cultures in an adult population

Streptococcus dysgalactiae subspecies equisimilis (SDSE) are isolated from the throat of patients with pharyngitis, although the clinical significance remains debated. We sought to determine the incidence and association with pharyngitis of SDSE in an adult veteran population. Organisms were phenotypically identified to subspecies and Lancefield group, with selective 16S rRNA gene sequencing. From 833 throat cultures, the overall frequency of SDSE was 3.4% (64% group C and 36% group G) as compared to 8.6% for S. pyogenes (GAS). SDSE was described as a large colony in only 29% of the original culture evaluations by bench technologists, and clinical symptoms were similar for GAS and SDSE. Laboratory algorithms that are limited to identification of only GAS or are based on Lancefield group or visual identification of “large-colony type” β hemolytic Lancefield group C and G streptococci may be missing or misidentifying SDSE along with Anginosus group streptococci.     

Culture and antigen detection tests for streptococcal tonsillopharyngitis.

A throat culture is necessary for accurate diagnosis of group A beta-hemolytic streptococcal tonsillopharyngitis. The use of penicillin therapy in every patient with sore throat results in overtreatment of 85 percent of children and 95 percent of adults presenting to family physicians with the complaint of sore throat. Indiscriminate use of penicillin also increases the risk of drug side effects and subjects some patients to unnecessary alterations of microbial ecology. The signs and symptoms of group A beta-hemolytic streptococcal tonsillopharyngitis are nonspecific, and reliable clinical diagnosis is difficult. Throat culture is cost-effective and, if properly obtained and processed, more than 95 percent accurate. Antigen detection tests (rapid strep tests) are a viable laboratory alternative to throat cultures if these tests are properly performed and if negative test results are confirmed with traditional throat culture.     

Significance of hemolytic streptococci for Nashville school children: clinical and serologic observations.

The results of this study (1969-1971 confirm previous findings that incidence rates for hemolytic and group A streptococci in Nashville school children fluctuate sporadically. During these two years, there was a significant decrease in streptococcal incidence and in typability of group A streptococci. A positive throat culture was not associated significantly more often with symptoms of an infection of the upper respiratory tract than when symptoms were absent. The larger the number of group A streptococci present in the throat culture, the more likely was a streptococcal antibody increase to occur. Nevertheless, some children with small numbers of group A streptococci had an antibody increase, and the degree of positivity of the throat culture was not a very accurate indication of whether an antibody response would occur. Epidemiologic factors such as age, sex, race, or crowding in the home did not seem to play a highly significant role in rates. Seasonal influences were marked in 1969-1970 but not in 1970-1971. Regarding socioeconomic background, the rates were consistently lower in Clemons school, which serves a predominantly black neighborhood of higher socioeconomic level, than in the other two schools. Our findings confirm that the incidence of acquisition of the hemolytic streptococcus is a continually changing, dynamic process among school children.     

Group A β-hemolytic streptococcal hemorrhagic colitis complicated with pharyngitis and impetigo

A 6-year-old boy with bloody diarrhea was diagnosed with group A β-hemolytic streptococcal hemorrhagic colitis. Complications included pharyngitis and impetigo, both caused by the same organisms. In addition to being isolated from stools, Streptococcus pyogenes was also isolated from skin lesions. Furthermore, a rapid group A streptococcal antigen test by throat swab was also positive. Hemorrhagic colitis caused by group A β-hemolytic streptococcus is extremely rare, and much rarer are its complications with pharyngitis and impetigo. Compared with findings in reports of group A β-hemolytic streptococcal proctitis and perianal and perineal diseases, this case suggests a distinct pathogenesis for hemorrhagic colitis.