Clinical outcomes and macrolide resistance in Mycoplasma pneumoniae infection in Scotland, UK.

Mycoplasma pneumoniae has a cyclical, epidemic pattern of infection and the most recent epidemic occurred in Europe in 2011. Macrolides are recommended for the treatment of M. pneumoniae respiratory tract infection, but macrolide resistance has been reported at low levels in Europe. The aim of the study was to examine the clinical impact of the recent M. pneumoniae epidemic in a hospital setting in Scotland and to determine whether macrolide-resistant strains are present. Data were analysed retrospectively for 307 patients with M. pneumoniae respiratory infection diagnosed in 2010 and 2011 in Edinburgh, UK. Genotypic macrolide resistance testing was also carried out in 32 patients in whom resistance was considered most likely, based on their clinical picture. We found that 175 patients (59 %) were admitted to hospital, 20 (7 %) were admitted to critical care and 97 (38 %) required oxygen. All 48 adult patients (100 %) were admitted to hospital, compared with 127 children (51 %). Adults were also more likely to require oxygen [odds ratio (OR) 4.964, P<0.001, 95 % confidence interval (CI) 2.129-11.803] and to be admitted to critical care (OR 4.909, P = 0.001, 95 % CI 1.735-13.829), compared with children. Macrolide resistance conferred by the 23S rRNA gene mutation was found in samples from 6 out of 32 patients (19 %) in the subset tested. The results suggest that the recent M. pneumoniae epidemic was associated with a significant burden of hospital admission locally. The study also describes the first case series of macrolide-resistant M. pneumoniae in the UK, indicating that macrolide resistance surveillance is warranted in preparation for the next epidemic.