This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Baldassarri, L.
Right arrow Articles by Orefici, G.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Baldassarri, L.
Right arrow Articles by Orefici, G.

 Previous Article  |  Next Article 

Journal of Clinical Microbiology, August 2006, p. 2721-2727, Vol. 44, No. 8
0095-1137/06/$08.00+0     doi:10.1128/JCM.00512-06
Copyright © 2006, American Society for Microbiology. All Rights Reserved.

Therapeutic Failures of Antibiotics Used To Treat Macrolide-Susceptible Streptococcus pyogenes Infections May Be Due to Biofilm Formation

Lucilla Baldassarri,1* Roberta Creti,1 Simona Recchia,1 Monica Imperi,1 Bruna Facinelli,2 Eleonora Giovanetti,2 Marco Pataracchia,1 Giovanna Alfarone,1 and Graziella Orefici1

Dipartimento di Malattie Infettive, Parassitarie ed Immunomediate, Istituto Superiore di Sanità, Roma,1 Istituto di Microbiologia e Scienze Biomediche, Università Politecnica delle Marche, Ancona, Italy2

Received 9 March 2006/ Returned for modification 24 April 2006/ Accepted 5 June 2006

Streptococcus pyogenes infections often fail to respond to antibiotic therapy, leading to persistent throat carriage and recurrent infections. Such failures cannot always be explained by the occurrence of antibiotic resistance determinants, and it has been suggested that S. pyogenes may enter epithelial cells to escape antibiotic treatment. We investigated 289 S. pyogenes strains isolated from different clinical sources to evaluate their ability to form biofilm as an alternative method to escape antibiotic treatment and host defenses. Up to 90% of S. pyogenes isolates, from both invasive and noninvasive infections, were able to form biofilm. Specific emm types, such as emm6, appeared to be more likely to produce biofilm, although variations within strains belonging to the same type might suggest biofilm formation to be a trait of individual strains rather than a general attribute of a serotype. Interestingly, erythromycin-susceptible isolates formed a significantly thicker biofilm than resistant isolates (P < 0.05). Among resistant strains, those carrying the erm class determinants formed a less organized biofilm than the mef(A)-positive strains. Also, prtF1 appeared to be negatively associated with the ability to form biofilm (P < 0.01). Preliminary data on a selection of strains indicated that biofilm-forming isolates entered epithelial cells with significantly lower efficiency than biofilm-negative strains. We suggest that prtF1-negative macrolide-susceptible or mef(A)-carrying isolates, which are poorly equipped to enter cells, may use biofilm to escape antimicrobial treatments and survive within the host. In this view, biofilm formation by S. pyogenes could be responsible for unexplained treatment failures and recurrences due to susceptible microorganisms.

* Corresponding author. Mailing address: Reparto di Malattie Batteriche Respiratorie e Sistemiche, Dipartimento di Malattie Infettive, Parassitarie ed Immunomediate, Istituto Superiore di Sanità, Viale Regina Elena, 299, 00161 Roma, Italy. Phone: 39.06.4990.2092. Fax: 39.06.4938.7112. E-mail: baldassa{at}iss.it.

Journal of Clinical Microbiology, August 2006, p. 2721-2727, Vol. 44, No. 8
0095-1137/06/$08.00+0     doi:10.1128/JCM.00512-06
Copyright © 2006, American Society for Microbiology. All Rights Reserved.



This article has been cited by other articles:

  • Doern, C. D., Roberts, A. L., Hong, W., Nelson, J., Lukomski, S., Swords, W. E., Reid, S. D. (2009). Biofilm formation by group A Streptococcus: a role for the streptococcal regulator of virulence (Srv) and streptococcal cysteine protease (SpeB). Microbiology 155: 46-52 [Abstract] [Full Text]  
  • Creti, R., Imperi, M., Baldassarri, L., Pataracchia, M., Recchia, S., Alfarone, G., Orefici, G. (2007). emm Types, Virulence Factors, and Antibiotic Resistance of Invasive Streptococcus pyogenes Isolates from Italy: What Has Changed in 11 Years?. J. Clin. Microbiol. 45: 2249-2256 [Abstract] [Full Text]  


Copyright © 2009 by the American Society for Microbiology.   For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»