Agreement between rapid antigen detection test and culture for group A streptococcus in patients recently treated for pharyngotonsillitis-a prospective observational study in primary care

ObjectiveThe aim was to compare rapid antigen detection test (RADT) and throat culture for group A streptococci (GAS) among patients recently treated with penicillin V for GAS pharyngotonsillitis.Design and settingThe study was a secondary analysis within a randomized controlled trial comparing 5 versus 10 days of penicillin V for GAS pharyngotonsillitis. Patients were recruited at 17 primary health care centres in Sweden.SubjectsWe included 316 patients >= 6 years of age, having 3-4 Centor criteria, a positive RADT and a positive throat culture for GAS at inclusion, and also having a RADT and throat culture for GAS taken at a follow-up visit within 21 days.Main outcome measuresRADT and conventional throat culture for GAS.ResultsThis prospective study showed 91% agreement between RADT and culture at follow-up within 21 days. Only 3/316 participants had negative RADT with a positive throat culture for GAS at follow-up, and 27/316 patients with positive RADT had a negative culture for GAS. Log rank test did not reveal any difference in the decline over time of positive tests between RADT and throat culture (p = 0.24). Agreement between RADT and throat culture for GAS at the follow-up was not associated with treatment duration, number of days from inclusion until follow-up, throat symptoms at follow-up, gender, or age.ConclusionRADT and culture for GAS agreed to a high extent also after recent penicillin V treatment. RADT for GAS means a low risk for missing the presence of GAS

Effects of penicillin V on the faecal microbiota in patients with pharyngotonsillitis-an observational study

Background The intestinal microbiota functions as a reservoir of antibiotic resistance. Objectives To evaluate penicillin V (phenoxymethylpenicillin) effects on the faecal microbiota with focus on beta-lactam resistance. Methods We included 31 primary care patients with group A streptococcal pharyngotonsillitis treated with penicillin V for 5 (800 mg x 4) or 10 days (1000 mg x 3). Twenty-nine patients contributed with three faecal swab samples each. The faecal specimens were collected at the start of penicillin V treatment, after the last dose and at follow-up 7-9 days after completed treatment. Samples were inoculated semiquantitatively on selective screening agar plates to study beta-lactam resistance, species shifts among Enterobacterales and enterococci, and colonization with Candida spp. and Clostridioides difficile. Representative colonies were identified using MALDI-TOF. Results were analysed by non-parametric statistical methods. Results An increase in the proportion of patients colonized with ampicillin-resistant Enterobacterales, from 52% to 86% (P = 0.007), and Enterobacterales with decreased susceptibility to third-generation cephalosporins, from 32% to 52% (P = 0.034), was observed between the first and second samples. This increase was no longer significant at follow-up. New colonization with ampicillin-resistant Enterobacterales species and non-Enterobacterales Gram-negative species was observed, and persisted at follow-up. Conclusions Following treatment with penicillin V, we observed decreased susceptibility to ampicillin and third-generation cephalosporins, and prolonged colonization with non-Escherichia coli Gram-negative species. These findings challenge the perception that penicillin V has limited ecological effect on the intestinal microbiota, and emphasizes the importance of avoiding even narrow-spectrum antimicrobials when possible.Funding Agencies|Public Health Agency of Sweden; Healthcare Committee, Region Vaestra Goetaland; Axel Linders Foundation; Skaraborg Institute [19/1039]</p

Penicillin V four times daily for five days versus three times daily for 10 days in patients with pharyngotonsillitis caused by group A streptococci: randomised controlled, open label, non-inferiority study

OBJECTIVE To determine whether total exposure to penicillin V can be reduced while maintaining adequate clinical efficacy when treating pharyngotonsillitis caused by group A streptococci. DESIGN Open label, randomised controlled non-inferiority study. SETTING 17 primary healthcare centres in Sweden between September 2015 and February 2018. PARTICIPANTS Patients aged 6 years and over with pharyngotonsillitis caused by group A streptococci and three or four Centor criteria (fever amp;gt;= 38.5 degrees C, tender lymph nodes, coatings of the tonsils, and absence of cough). INTERVENTIONS Penicillin V 800 mg four times daily for five days (total 16 g) compared with the current recommended dose of 1000 mg three times daily for 10 days (total 30 g). MAIN OUTCOMES MEASURES Primary outcome was clinical cure five to seven days after the end of antibiotic treatment. The noninferiority margin was prespecified to 10 percentage points. Secondary outcomes were bacteriological eradication, time to relief of symptoms, frequency of relapses, complications and new tonsillitis, and patterns of adverse events. RESULTS Patients (n=433) were randomly allocated to the five day (n=215) or 10 day (n=218) regimen. Clinical cure in the per protocol population was 89.6% (n=181/202) in the five day group and 93.3% (n=182/195) in the 10 day group (95% confidence interval -9.7 to 2.2). Bacteriological eradication was 80.4% (n=156/194) in the five day group and 90.7% (n=165/182) in the 10 day group. Eight and seven patients had relapses, no patients and four patients had complications, and six and 13 patients had new tonsillitis in the five day and 10 day groups, respectively. Time to relief of symptoms was shorter in the five day group. Adverse events were mainly diarrhoea, nausea, and vulvovaginal disorders; the 10 day group had higher incidence and longer duration of adverse events. CONCLUSIONS Penicillin V four times daily for five days was noninferior in clinical outcome to penicillin V three times daily for 10 days in patients with pharyngotonsillitis caused by group A streptococci. The number of relapses and complications did not differ between the two intervention groups. Five day treatment with penicillin V four times daily might be an alternative to the currently recommended 10 day regimen.Funding Agencies|Public Health Agency of Sweden; Healthcare Committee, Region Vastra Gotaland</p