Mycoplasma pneumoniae infection can cause pneumonia, particularly in children. Global increase in macrolide-resistant M. pneumoniae is of concern due to limited therapeutic options. We describe the detection of macrolide resistance-conferring mutations in 9.3% of 43 clinical specimens where M. pneumoniae was detected in England and Wales from September 2014-September 2015. This study aims to impact by highlighting the presence of macrolide resistance in M. pneumoniae positive patients, promoting increased clinical vigilance.
Macrolide resistance determinationThe Bacteriology Reference Department, Public Health England (PHE), London, receives specimens from England and Wales for M. pneumoniae testing and confirmatory testing. Here we detected M. pneumoniae by qPCR in 60 clinical specimens from 60 patients (Cambridge, Leeds, London, Manchester, Nottingham and Oxford) that were submitted to PHE between 1 September 2014 and 1 September 2015. DNA extractions from specimens, where M. pneumoniae was detected, were screened for point mutations known to confer macrolide resistance. Mutations in domain V of the 23S rRNA were detected by a modified version of the method described by Li et al., 2009 [3], wherein the entire region of interest is amplified and sequenced as one product. Primers used were as follows: forward primer 5'-ATCTCTTGACTGTCTCGGC-3' and reverse primer 5'-TACAACTGGAGCATAAGAGGTG-3'.Of the 60 specimens, 17 (28.3%; 95% confidence interval (CI): 18.4--40.8) contained insufficient DNA to determine macrolide resistance-conferring mutations. Of the remaining 43 specimens mutations in the 23S rRNA known to confer macrolide resistance were found in four (9.3%; 95% CI: 3.1-22.2). Of these 43 specimens, 32 were from a single city in England, Leeds, and a single specimen among these was positive for the mutation, 3.1% (95% CI: 0.01-17.1). The cases identified with point mutations known to confer macrolide-resistant M. pneumoniae were in two women and two men, respectively, aged > 15 to <65 years old. Three were hospitalised with pneumonia (Table) with no known connection between patients.Interestingly, two of the macrolide-resistant cases were patients that had recently arrived from the United States (exact timeline unknown); of which one had received clarithromycin whilst undergoing treatment in the UK. The origins of the infecting M. pneumoniae strains in these two cases may have been external to England and Wales. The other two cases were from separate cities in England. All macrolide resistanceconferring mutations were A2058G (Escherichia coli numbering) point mutation in the 23S rRNA.