Open AccessGroup A Streptococcus Colonies From a Single Throat Swab Can Have Heterogeneous Antimicrobial Susceptibility Patterns
Author(s) -
Aurélie Vandevoorde,
Sabrina Ascenzo,
Véronique Yvette Miendje Deyi,
Georges Mascart,
Anne-Laure Mansbach,
Marguerite Landsberg,
Pierre Luc Dreze,
Andrew C. Steer,
Laurence Van Melderen,
Pierre Smeesters
Publication year - 2013
Publication title -
the pediatric infectious disease journal/the pediatric infectious disease journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.028
H-Index - 140
eISSN - 1532-0987
pISSN - 0891-3668
DOI - 10.1097/inf.0b013e31827c9796
Subject(s) - pharyngitis , throat , antibiotics , medicine , microbiology and biotechnology , antibiotic resistance , antimicrobial , streptococcaceae , streptococcus , genotype , group a , throat culture , acute pharyngitis , streptococcus pneumoniae , biology , bacteria , gene , genetics , surgery
This study describes for the first time heterogeneity of antibiotic resistance profiles among group A Streptococcus isolates originating from a single throat swab in patients with acute pharyngitis. For each throat swab, 10 group A Streptococcus colonies were randomly selected from the primary plate and subcultured to a secondary plate. These isolates were characterized by various phenotypic and genotypic methods. Our results demonstrated that differing antibiotic resistance profiles were present in 19% of pediatric patients with acute pharyngitis before antimicrobial treatment. This heterogeneity likely resulted from horizontal gene transfer among streptococcal isolates sharing the same genetic background. As only a minority of colonies displayed antibiotic resistance among these heterogeneous samples, a classical diagnostic antibiogram would have classified them in most instances as "susceptible," although therapeutic failure could be caused by the proliferation of resistant strains after initiation of antibiotic treatment.