Factors involved in treatment failures following oral penicillin therapy of streptococcal pharyngitis

Systematic review of factors contributing to penicillin treatment failure in Streptococcus pyogenes pharyngitis

Objective

Review the evidence for various explanations for microbiologic treatment failure following use of penicillin in group A streptococcal (GAS) tonsillopharyngitis.

DATA SOURCE

Systematic review of the literature based on Medline and EMBASE searches, and review of reference lists of included studies.

RESULTS

The explanations for penicillin treatment failure in GAS tonsillopharyngitis include 1) carrier state, 2) lack of compliance, 3) recurrent exposure, 4) in vivo copathogenicity of β-lactamase–producing normal pharyngeal flora, 5) in vivo bacterial coaggregation, 6) poor antibiotic penetration to tonsillopharyngeal tissue, 7) in vivo eradication of normal protective flora, 8) early initiation of antibiotic therapy resulting in suppression of an adequate host immune response, 9) intracellular localization of GAS, 10) GAS tolerance to penicillin, 11) contaminated toothbrushes or orthodontic appliances, and 12) transmission from the family pet. There is very little type I or II evidence to support any of the above-cited explanations for treatment failure in GAS tonsillopharyngitis; available studies are mostly observational (in patients) or laboratory-based without clinical confirmation.

CONCLUSION

Multiple explanations have been offered by investigators to explain penicillin treatment failures in GAS tonsillopharyngitis, but the evidence base to support the proposed explanations is generally weak by current standards. Further research is needed to better understand the mechanism(s) of penicillin treatment failure in GAS tonsillopharyngitis.

Transmission of Streptococcus pyogenes causing successive infections in a family

The objective of this study was to determine the characteristics of Streptococcus pyogenes isolated during a 10-month period from members of a family with infections and asymptomatic carriage. T-serotyping and pulsed-field gel electrophoresis confirmed that distinct GAS clones were introduced into the family over a short period of time.

The role of household contacts in the transmission of group A streptococci

The intrafamilial spread and recurrence of group A beta-haemolytic streptococci (GAS) infections was investigated. The evaluation was based on 114 patients and their families treated with penicillin for 5 days and followed for 1 month. GAS of the same T-type as that of the isolate from the index case were found in other family members in 33% of the families. Genetic finger-printing using RFLP was performed on 33 of the isolates. The mothers dominated among the index cases, 40 patients experienced recurrences, 27 of them were clinical 28 recurrences occurred within 10 days after the end of treatment. Of 20 T-typed patients with early clinical treatment failures, infected family members were detected in 16 families (p < 0.001). In 19% of the patients GAS could be isolated from the nose. These patients had more ill family members than did other patients. An extensive intrafamilial streptococcal spread was found. Most recurrences of GAS pharyngotonsillitis after penicillin treatment are probably due to "ping pong" infection from family members.

Pharyngitis

This article reviews the commonly encountered agents causing acute inflammation of the pharynx and tonsils, with special attention to a practical approach for identifying and dealing with the group A beta-hemolytic streptococcus. Ubiquitous viral agents such as Epstein-Barr virus, rhinovirus, and adenovirus are reviewed. Some agents such as group A beta-hemolytic streptococcus and Epstein-Barr virus are susceptible to treatment. Additionally, unusual infectious agents and noninfectious causes of pharyngitis are enumerated.

A double-blind, multicenter comparative study of two regimens of clindamycin hydrochloride in the treatment of patients with acute streptococcal tonsillitis/pharyngitis

In a double-blind, prospective, randomized, multicenter study, 164 patients with a clinical and bacteriologic diagnosis of acute streptococcal tonsillitis/pharyngitis were enrolled to compare the efficacy and safety of two regimens of clindamycin. A rapid identification test of Group A beta-hemolytic streptococci (GABHS) was used to initiate the therapy; however, a positive tonsillar/pharyngeal culture was required at pretreatment to determine if the patient was assessable. Another culture was repeated at least 2 days after the 10 days of drug therapy. From 164 patients enrolled (mean age, 27.7 years; range, 14 to 60 years), 141 were assessable for efficacy; 22 patients were excluded because they did not have a positive culture at pretreatment and 1 patient did not complete the study due to a side effect (rash). All patients were included in the safety analysis. Patients received either clindamycin hydrochloride capsules 150 mg four times per day (QID) or clindamycin hydrochloride capsules 300 mg two times per day (BID) and placebo capsules BID for 10 days. There were no significant differences between groups in terms of demographics, medical history, and evolution of symptoms. The clinical efficacy rate in the two groups at day 12 was as follows: QID group--cured, 64 (92.8%) of 69 patients; improved, 5 (7.2%) of 69 patients; BID group--cured, 67 (93.1%) of 72 patients; improved, 5 (6.9%) of 72 patients. There were no significant differences between the groups. Both regimens were well tolerated with only 1 patient in the QID group who did not complete the therapy due to a rash.(ABSTRACT TRUNCATED AT 250 WORDS)

Randomized evaluation of benzathine penicillin V twice daily versus potassium penicillin V three times daily in the treatment of group A streptococcal pharyngitis. Pharyngitis Study Group

In a randomized, prospective, multicenter study the clinical and bacteriological efficacies of three dosage schedules with two different salts of oral penicillin V suspensions (regimen 1: potassium salt of penicillin V, 50,000 U/kg of body weight per day in three divided doses; regimen 2: benzathine salt of penicillin V, 50,000 U/kg of body weight per day in two divided doses; and regimen 3: benzathine salt of penicillin V, 100,000 U/kg of body weight in two divided doses) for the treatment of streptococcal pharyngitis were evaluated. Children with clinical signs of acute pharyngitis and a positive throat culture for group A beta-hemolytic streptococci (GABHS) were eligible. There was no difference between the treatment groups with respect to the overall clinical success rate. Eradication of the original serotype of GABHS from throat cultures was achieved in 87.1% (regimen 1), 85.5% (regimen 2) and 87.7% (regimen 3) of patients. The incidence of potential drug-related adverse events was significantly higher in patients treated with regimen 3. The results of this and earlier studies strongly suggest that oral penicillin given twice daily should be the recommended treatment for the initial treatment of pharyngitis due to GABHS. Doubling the total daily dose is not beneficial in the usual clinical setting. Because of its favorable pharmacokinetics, the benzathine salt of penicillin V appears to be well suited for a twice-a-day dosage schedule.

Streptococcal pharyngitis: a review of pathophysiology, diagnosis, and management

Pharyngitis is an illness frequently treated by emergency physicians and primary care practitioners. It is the subject of much controversy regarding optimal treatment in the acute care setting. This review discusses pertinent aspects of the pathophysiology, clinical features, diagnosis, and treatment based on available literature. This review is also meant to serve as a bibliographic resource for some of the controversies of this complex topic.

Lack of impact of early antibiotic therapy for streptococcal pharyngitis on recurrence rates

To determine whether recurrence rates for group A beta-hemolytic streptococcal (GABHS) pharyngitis are related to the time of initiation of antibiotic therapy, we randomly assigned 113 patients with GABHS pharyngitis either to a group that began a 10-day course of penicillin V at the time of diagnosis or to a group that began the same antibiotic regimen after a dealy of 48 hours. Follow-up throat culture specimens were obtained 4 days, 2 months, and 4 months after the completion of antibiotic therapy, as well as during any interim episodes of acute pharyngitis. Serotyping of all GABHS isolates was performed to distinguish between recurrences with homologous serotypes and new acquisitions with heterologous serotypes. There was no significant difference between the two treatment groups in age, gender, duration of illness before enrollment in the study, initial clinical presentation, or compliance. Of the 50 patients in the immediate-treatment group, 6 (12%) had homologous serotypes of GABHS isolated on one of the follow-up throat cultures. Of the 63 patients in the delayed-treatment group, 9 (14%) had homologous serotypes of GABHS isolated on one of the follow-up throat cultures. These data indicate that a 48-hour delay in the initiation of penicillin therapy for GABHS pharyngitis does not reduce the recurrence rate.

Cefadroxil versus penicillin in the treatment of streptococcal tonsillopharyngitis

In a randomized multicentre study the efficacy of phenoxymethyl-penicillin and cefadroxil was tested in the treatment of acute tonsillopharyngitis caused by group A streptococci. These organisms were detected in 269 of the 300 children studied. Of the 239 patients in whom results could be evaluated, 121 received penicillin and 118 cefadroxil. After ten days of therapy the microbiological failure rate was 19% in the penicillin group and 6.8% in the cefadroxil group (p less than 0.01). Ten of 23 cases of microbiological failure in the penicillin group and two of eight in the cefadroxil group also had clinical symptoms of infection. All streptococcal isolates were sensitive to penicillin, cefadroxil and clindamycin with the exception of one strain with intermediate sensitivity to cefadroxil. Seven strains had intermediate sensitivity to erythromycin and one was resistant. No penicillin tolerance was observed. Patients in whom penicillin therapy failed more frequently had beta-lactamase producing staphylococci in the pharyngeal flora in comparison to successfully treated patients. The clinical and bacteriological results showed that cefadroxil was clearly superior to penicillin.

Five versus ten days treatment of group A streptococcal pharyngotonsillitis: a randomized controlled clinical trial with phenoxymethylpenicillin and cefadroxil

216 patients aged greater than or equal to 7 years with febrile group A streptococcal pharyngotonsillitis were randomly assigned to 3 treatment groups receiving either phenoxymethylpenicillin for 5 days followed by placebo for 5 days, phenoxymethylpenicillin for 10 days, or cefadroxil for 10 days. 209 patients completed treatment, 70 subjects in each phenoxymethylpenicillin group and 69 in the cefadroxil group. Within 1 week after completion of the antibiotic treatment significantly more recurrences with the same T-type as the initial streptococcal strain occurred in the 5-day treatment group (27%) as compared with the two 10-day groups (6% and 3%, respectively). The cumulative rate of recurrences (irrespective of T-type) within 2 months from the start of therapy was 55% among patients treated with phenoxymethylpenicillin for 5 days, 24% among those treated for 10 days with this drug and 19% among patients receiving cefadroxil. Obviously, one important factor to avoid recurrence of group A streptococcal pharyngotonsillitis is the length of antibiotic treatment and, in our opinion, it is not advisable to change the current recommendation of 10 days treatment.

Evaluation of beta-lactamase activity and microbial interference in treatment failures of acute streptococcal tonsillitis

Out of 169 patients with streptococcal tonsillitis treated with phenoxymethylpenicillin, 13 (8%) developed a new clinical infection with the same streptococcal strain within 2 weeks of completing the therapy (clinical treatment failure) and 24 (14%) were clinically healthy but harboured the same streptococcal strain after treatment (bacterial treatment failure). Patients with clinical treatment failure showed beta-lactamase activity in their saliva pellet significantly more often than patients with bacterial treatment failure, healed streptococcal tonsillitis or non-streptococcal tonsillitis as well as healthy controls. In an interference study, clinical treatment failures were compared with healthy streptococcal carriers, i.e. persons living in the same household and harbouring the same beta-streptococcal strain. 11/12 healthy carriers had alpha-streptococci with interfering activity against their own beta-streptococcal strain, while the corresponding figure for the clinical treatment failures was 2/13. Furthermore, 6/12 healthy carriers had beta-streptococci inhibiting their own alpha-strains, while the streptococci in 11/13 clinical treatment failures had this ability. The beta-lactamase activity and the interference between alpha- and beta-streptococci may be a contributory cause to treatment failure in streptococcal tonsillitis.

Pharmacokinetics of phenoxymethylpenicillin in tonsils

The pharmacokinetics of phenoxymethylpenicillin in tonsillar tissue was studied in 33 patients who underwent tonsillectomy, mainly because of repeated tonsillitis or peritonsillitis. The patients were operated on 30-240 min after an oral penicillin dose of 12.5 mg/kg body weight. The mean serum concentration was 2.8 micrograms/ml for 10 patients operated upon 80-95 min after drug administration. The mean tissue concentration for these patients at the same time was 0.6 micrograms/g. The mean concentration of penicillin in tissue after 240 min was 0.05 micrograms/g. 19% of the serum concentration was recovered in the tonsillar tissue. No significant difference between penicillin concentration in the centre or surface of the tonsils was found. The tissue concentration was calculated to be above 0.03 micrograms/ml for at least 4-5 h. 30% of the patients harboured penicillinase producing bacteria on their tonsils, mainly Staphylococcus aureus. These patients had a lower tissue concentration than those lacking the bacteria, but the difference was not statistically significant (p = 0.095).

Penicillin V and rifampin for the treatment of group A streptococcal pharyngitis: a randomized trial of 10 days penicillin vs 10 days penicillin with rifampin during the final 4 days of therapy

To improve the bacteriologic and clinical cure rates of streptococcal pharyngitis, 79 children were randomly assigned to receive penicillin V alone for 10 days (39 patients) or penicillin for the same duration and rifampin during the last 4 days of penicillin therapy (40 patients). Eleven patients given penicillin had evidence of bacteriologic failure (including eight with relapse of clinical illness) on repeat cultures done 4 to 7 days after treatment, whereas there were no failures in children given combination therapy (P = 0.0015). All eight symptomatic children improved with penicillin-rifampin therapy and subsequent cultures were negative, whereas three asymptomatic children continued to harbor group A streptococci even after combination therapy. Antibody response by antistreptolysin O or antideoxyribonuclease B assay was seen in 50.6% of patients; the antibody responses in both groups were comparable. These results show that addition of rifampin to the penicillin regimen improves the clinical and bacteriologic cure rates in children with streptococcal pharyngitis.

Concentrations of cloxacillin and erythromycin in the tonsils of children after administration of therapeutic doses

The treatment of infections in the ring of Waldeyer in children is an ever present problem. Most infections are caused by group A streptococci, and various antibiotics are routinely used for their treatment. In many cases, however, this treatment is ineffective as demonstrated by prolonged disease duration and recurrences. This may be due to the resistance of the pathogens to the used antibiotic, too low dose, or inadequate penetration of the drug into the focus of infection. To explain this problem the reported investigation was undertaken carrying out bacteriological investigations of the removed tonsils and determining antibiotic concentrations in tonsil homogenates and in the serum after cloxacillin and erythromycin treatment of 45 children aged 4-14 years subjected to tonsillectomy or adenotomy . It was found that the most frequent aetiological factors in angina and adenoiditis were group A streptococci. Cloxacillin and erythromycin are the antibiotics penetrating well into the lymphoid tissue and reaching high concentrations in the focus of infection but the courses of treatment should not be shorter than 10 days.

Treatment of Group A streptococcal pharyngitis in children. Results of a prospective, randomized study of four antimicrobial agents

Penicillin V, benzathine/procaine penicillin G, cefadroxil monohydrate, and erythromycin estolate were randomly assigned for therapy of group A streptococcal pharyngitis in 198 children. All patients improved with in 24 hours of initiating therapy. Reinfection with a new group A streptococcal serotype occurred in 13 patients, 12 developing 7 to 12 days after stopping therapy and 11 becoming symptomatic. Relapse with the same organism occurred in 16 patients, only 5 (31%) of whom were symptomatic. Antibody titer rises, antibiotic resistance of group A organisms, presence of penicillinase-producing staphylococci, and lack of compliance were not related to recurrent infections. There were no significant differences between the failure rates of the four test drugs: penicillin V, 12%; benzathine/procaine penicillin G, 12%; cefadroxil monohydrate, 5%; and erythromycin, 2%.

Susceptibility of group A beta-hemolytic Streptococcus isolates to penicillin and erythromycin

We have reevaluated the antibiotic susceptibilities of group A beta-hemolytic streptococci in view of recent reports of a high prevalence of erythromycin resistance in Japan and of an increase in penicillin treatment failures in the United States. A total of 474 isolates recovered during a 2- to 3-month period in 1980 were tested. All were susceptible by microtiter broth dilution to a penicillin concentration of less than or equal to 0.03 micrograms/ml (minimal inhibitory concentration), and 473 were killed by less than or equal to 0.06 micrograms/ml (minimal inhibitory concentration). Erythromycin minimal inhibitory concentrations showed a bimodal distribution: 95% were less than or equal to 0.06 micrograms/ml, and 5% were greater than or equal to 1 microgram/ml. Of the minimal bactericidal concentrations, 21% were greater than or equal to 1 microgram/ml and 3% were greater than or equal to 16 micrograms/ml. Group A beta-hemolytic streptococci remain susceptible to the inhibitory and bactericidal actions of penicillin, thus providing no in vitro explanation for the bacteriological relapses reported in some clinical studies. Unlike the Japanese experience, only 5% of our isolates were resistant to erythromycin (minimal inhibitory concentration, greater than or equal to 1 microgram/ml); however, 22% were tolerant (ratio of minimal inhibitory/bactericidal concentrations, greater than or equal to 32).

Streptococcal infection in a Junior Detention Centre: a five-year study

In 1972 more than 20% of boys admitted to a closed community (Junior Detention Centre) developed acute tonsillitis and group-A streptococci were isolated from more than 40% of all boys at some time during their stay of two months. The most common serotype was M-type 5, which has frequently been associated with rheumatic fever in other epidemics; four cases of rheumatic fever occurred between 1972 and 1977. Various methods were tried to eliminate the infection, but only full penicillin prophylaxis (0.25 g oral penicillin 4 times a day for 10 days) to all boys on entry appeared to be effective. In a sample of cases of acute tonsillitis, group-A haemolytic streptococci were isolated from 31.7% by the use of dry swabs or unenriched transport medium, but with enrichment medium duplicate swabs, 77.6% yielded positive results. We question the current practice in some laboratories of reporting positive cultures only when more than ten colonies of beta-haemolytic streptococci are present. In this survey viruses did not appear to be an important cause of acute tonsillitis. High titres of streptococcal antibodies (antistreptolysin O, anti-desoxyribonuclease B and anti-M associated protein) were found, not only in cases and carriers, but in boys on entry to the centre. This supports epidemiological evidence that adolescent boys are particularly prone to streptococcal throat infections.

Erythromycin: a review of its uses in pediatric practice

Erythromycin continues to be a valuable and useful antimicrobial agent in children. Its low index of toxicity, freedom from sensitization, and reliable absorption and when administered orally contribute to make it an attractive agent in the treatment of a variety of minor respiratory and skin infections, especially in those situations where real or potential allergy to penicillin exists. Additional major uses are in the eradication of the carrier state in whooping cough and in diphtheria, especially in those instances when oral therapy can be tolerated. Dispite use over more than two decades, resistance developing in formerly susceptible organisms has not been a problem and thus seems unlikely to become so in the future.

The pediatric medical triangle

The pediatric patient has many needs which are often ignored in the ambulatory environment partially due to participation in a medical triangle. This medical triangle and its participants frequently contribute to the development of an ineffective physician-patient encounter which, in turn, may lead to numerous problems including parental dissatisfaction, altered health care behavior and noncompliance with clinic appointments and drug therapy. This article attempts to summarize some of these problems with the pediatric medical triangle as well as some of the special needs of this patient.

Comparison of erythromycin ethyl succinate, stearate and estolate treatments of group A streptococcal infections of the upper respiratory tract

The microbiologic and clinical responses of acute Group A beta-hemolytic streptococcal infections of the upper respiratory tract to oral treatment with erythromycin ethyl succinate, stearate, and estolate were studied in 303 patients. Streptococcal M and T typing was done on all positive cultures. The overall cure rate was 95.4 per cent, with no statistically significant differences in clearing organisms from the pharynx. Of the 285 cured patients who completed the prescribed follow-up period, 11 had recurrences between the 12th and 31st day after initiation of therapy, and five developed new infections. No cases of rheumatic fever or glomerulonephritis were encountered during a follow-up study. Eight gastrointestinal reactions and one transient rash occurred. Results with these forms of erythromycin compare favorably with published results for similar infections treated with oral penicillins.

Identification and treatment of group A beta-hemolytic streptococcal infections. Role of the pediatrician and the nurse-practitioner

The risk of rheumatic fever in childhood continues to be high in the United States, especially where crowded living conditions promote epidemic spread of streptococcal pharyngitis. Early identification and appropriate penicillin therapy shorten the acute streptococcal illness and greatly reduce the occurrence of sequelae. Florid disease usually presents no therapeutic dilemma, but a firm scientific basis for definitive diagnosis and treatment of the carrier state, inapparent infection, mild clinical disease, or relapse is lacking. Appreciation of these unresolved issues is helpful in developing practical therapeutic guidelines for physicians and assistants. Public health throat culture programs may provide the initiative for effective community streptococcal control, but centralization of facilities on a large scale may delay institution of therapy because of slow reporting of culture results. Although delay in treatment may engender increased risk of rheumatic fever, institution of appropriate penicillin therapy may prevent rheumatic fever even if started after an untreated streptococcal tonsillitis has run its usual 5 day symptomatic course. Throat cultures are necessary in diagnosis, but clinical judgment must be exercised in initiating penicillin therapy before the culture is reported. The relative morbidity and ultimate mortality of the sequelae to streptococcal disease suggest assignment of national health priority to the development of preventive programs. Utilization of nurse-practitioners or similarly trained medical assistants seems necessary to effective delivery of care in the crowded areas of highest rheumatic fever incidence.