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Publication Abstract from PubMed

Fosfomycin targets the first step of peptidoglycan biosynthesis in Streptococcus pneumoniae catalyzed by UDP-N-acetylglucosamine enolpyruvyltransferase (MurA1). We investigated whether heteroresistance to fosfomycin occurs in S. pneumoniae. We found that of 11 strains tested all but one (Hungary19A) displayed heteroresistance and that deletion of murA1 abolished heteroresistance. Hungary19A differs from the other strains by a single amino-acid substitution in MurA1 (Ala364Thr). To test whether this substitution is responsible for lack of heteroresistance, it was introduced into strain D39. The heteroresistant phenotype of strain D39 was not changed. Furthermore, no relevant structural differences between MurA1 of the heteroresistant strain D39 or the non-heteroresistant strain Hungary19A were found in their crystal structures. Our results reveal that heteroresistance to fosfomycin is the predominant phenotype in S. pneumoniae and that MurA1 is required for heteroresistance to fosfomycin but is not the only factor involved. The findings provide a caveat for any future use of fosfomycin in the treatment of pneumococcal infections.

Heteroresistance to fosfomycin is predominant in Streptococcus pneumoniae and depends on murA1 gene.,Engel H, Gutierrez-Fernandez J, Fluckiger C, Martinez-Ripoll M, Muhlemann K, Hermoso JA, Hilty M, Hathaway LJ Antimicrob Agents Chemother. 2013 Apr 9. PMID:23571543^[2]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.