First report of macrolide-resistant strains and description of a novel nucleotide sequence variation in the P1 adhesin gene in Mycoplasma pneumoniae clinical strains isolated in France over 12 years.

Mycoplasma pneumoniae isolates are divided in two types based on the sequence variations in the P1 adhesin gene. The type of P1 adhesin gene of 155 clinical isolates of M. pneumoniae collected in France between 1994 and 2006 was determined by a PCR-restriction fragment length polymorphism method. Until 1995, all strains belonged to type 1. In 1996 and 1997, type 1 was still predominant, but type 2 increased. Finally, since 1998, both types were present in about the same proportion. In our study, a novel sequence of the P1 adhesin gene was described in one strain. This strain could not be classified into type 1 or 2 because of variability in both P1 gene repeat elements, RepMP4 and RepMP2/3. This new sequence was certainly issued from recombination with repetitive sequences localized outside of the P1 gene in the M. pneumoniae chromosome. Moreover, MICs of erythromycin, tetracycline, and ciprofloxacin were determined for the 155 isolates. All isolates remained susceptible to tetracycline and ciprofloxacin, but two macrolide-resistant strains, isolated from two children in 1999, were identified. They harbored an A-to-G substitution at position 2058 or 2059 (Escherichia coli numbering) in domain V of 23S rRNA, associated with resistance to macrolides, lincosamides, and ketolides. To our knowledge, this is the first description of macrolide-resistant isolates of M. pneumoniae in France, but at this time, there is no sign of recent diffusion of resistant strains.