[Emergence of macrolide resistant Streptococcus pyogenes strains in pediatric patients in France]. / Emergence de la résistance aux macrolides chez Streptococcus pyogenes en pédiatrie.

A total of 206 recent throat isolates of Streptococcus pyogenes collected between 2002 and 2004 from children were tested for their susceptibility to penicillin, amoxycillin, erythromycin, clarythromycin and clindamycin. The erythromycin resistant isolates were further studied for their genetic mechanism of resistance by means of PCR. In all, 14.5% of the strains were erythromycin resistant and 13.5 and 1% expressed the constitutive MLS(B) and M resistance phenotypes and harbored the ermB and mef A genes respectively.

[Current Streptococcus pyogenes sensitivity responsible for acute tonsillopharyngitis in France]. / Sensibilité actuelle en France de Streptococcus pyogenes responsable d'angine aiguë.

OBJECTIVE: Current guidelines recommend that only tonsillopharyngitis due to group A beta-haemolytic streptococcus (GABHS) diagnosed by rapid diagnostic test should be treated with antibiotics. Empirical antibiotic therapy must be based on epidemiological surveillance of resistance of GABHS to antibiotics. The aim of our study was to assess the activity of antimicrobial agents currently recommended for the treatment of GABHS tonsillopharyngitis. Method The activity of penicillin G, amoxicillin, cefaclor, cefpodoxime, cefuroxime, erythromycin, clarithromycin and clindamycin was determined against 93 consecutive GABHS isolates collected in 2002. MIC50 and MIC90 of antibiotics tested were determined by agar dilution method according to CA-SFM guidelines. Macrolide resistance genes (ermA, ermB, mef) were detected by PCR. Genetic diversity of erythromycin-resistant isolates was analysed by pulsotypic method after digestion by SmaI (Finger-printing II, Biorad). RESULTS: The activity of beta-lactam agents tested was similar and no resistant strain was detected (0%). Nevertheless, this study shows an increasing emergence of erythromycin-resistant GABHS strains reaching 14% in 2002 (vs. 6.2% in a previous study carried out in 1996-1999). CONCLUSION: The empirical antibiotic therapy of tonsillopharyngitis must consider, on the one hand, the high risk of GABHS eradication failure associated with in vitro resistance to erythromycin and clarithromycin, and on the other hand, the sustained susceptibility of GABHS to beta-lactam agents. These results reinforce the recommendations to use beta-lactam agents as first line treatment of GABHS tonsillopharyngitis.

Mechanisms of macrolide resistance in clinical group B streptococci isolated in France.

Macrolide susceptibility was investigated in clinical group B streptococci obtained from neonates or pregnant women in 2000 in France. Of 490 consecutive isolates, 18% were resistant to erythromycin. The erm(B), erm(A) subclass erm(TR), and mef(A) genes were harbored by 47, 45, and 6% of these strains, respectively. Two isolates did not harbor erm or mef genes.

Impact of antimicrobial therapy on nasopharyngeal carriage of Streptococcus pneumoniae, Haemophilus influenzae, and Branhamella catarrhalis in children with respiratory tract infections.

We conducted a multicenter prospective study to document changes in nasopharyngeal carriage of Streptococcus pneumoniae, Haemophilus influenzae, and Branhamella catarrhalis during antibiotic therapy. A cohort of 629 children with respiratory tract infections underwent nasopharyngeal sampling before and after antibiotic treatment. Susceptibility testing, serotyping, arbitrarily primed polymerase chain reaction, and pulsed-field gel electrophoresis were used to compare pretreatment and posttreatment strains of S. pneumoniae. A significant decrease in carriage of all 3 species (especially S. pneumoniae and B. catarrhalis) was recorded. The increase in the proportion of penicillin-resistant pneumococci (PRP; 66% vs. 44%) was due to the decreased carriage of penicillin-susceptible pneumococci (71 of 629 vs. 176 of 629). The risk of PRP carriage in a given child did not increase. None of the children was found to harbor genetically related strains with increased minimum inhibitory concentrations. Given the multiple resistance of PRP, beta-lactam antibiotic therapy also increased the incidence of macrolide-resistant strains, whereas macrolides selected both macrolide- and penicillin-resistant strains.

Resistance to macrolides in Streptococcus pyogenes in France in pediatric patients.

A total of 1,500 recent throat isolates of Streptococcus pyogenes collected between 1996 and 1999 from children throughout France were tested for their susceptibility to erythromycin, azithromycin, josamycin, clindamycin, and streptogramin B. The erythromycin-resistant isolates were further studied for their genetic mechanism of resistance, by means of PCR. The clonality of these strains was also investigated by means of serotyping and ribotyping. In all, 6.2% of the strains were erythromycin resistant, and 3.4 and 2.8% expressed the constitutive MLS(B) and M resistance phenotypes and harbored the ermB and mefA genes, respectively; ermTR was recovered from one isolate which also harbored the ermB gene. Ten serotypes and 8 ribotypes were identified, but we identified 17 strains by combining serotyping with ribotyping. Among the eight ribotypes, the mefA gene was recovered from six clusters, one being predominant, while the ermB gene was recovered from four clusters, of which two were predominant.

[Bacterial epidemiology of pharyngitis in pediatric private practice]. / Epidémiologie bactérienne des angines en pratique pédiatrique de ville.

OBJECTIVES: While viruses are usually the causal agents of common sore throat in children, bacterial infections cannot be distinguished solely on the basis of clinical presentation. Thus most physicians in France prefer to prescribe antibiotics in order to prevent rheumatismal complications of group A streptococcal infections. We updated current epidemiological data on bacterial pharyngitis in paediatric out-patient clinics. METHODS: A prospective study was conducted from March 1 to June 1, 1992 by 9 physicians. Throat swabs were obtained from 102 controls and from 307 patients with acute pharyngitis. Samples were transferred to the same bacteriology laboratory for examination. RESULTS: The mean age of the children was 6.1 years for patients and 7.2 years for controls. Throat swabs were inoculated for culture within a mean delay of 22.6 hours. Cultures were performed on Columbia blood medium with nalidixic acid and colistin then incubated in CO2 enriched atmosphere and on trypticase blood soy medium + 3.5% NaCl. Group A streptococcal strains were identified by search for beta-haemolysis and latex characterisation of group A polyosides. Group A streptococcal strains were found in 8.8% of the controls and 36.8% of the patients. Groups B, C or G streptococci were found in 10.8 et 11.4% of the controls and patients respectively (NS). Arcanobacterium haemolyticum was never isolated. Clinical association of sore throat, erythematous pharyngitis, fever > 38 degrees C and cervical lymph nodes was found in only 33.63% of the sore throat cases with group A streptococcal infection and in 7.73% of those without group A streptococcal infection (p < 0.0001, sensitivity 33%, specificity 92%). CONCLUSION: These results emphasize the necessity either to treat all pharyngitis or to do throat swabs or rapid group A streptococcal tests for diagnosis.