Chinese study of serogroup 6 S. pneumoniae finds no antibiotic-resistant clones

A survey of serogroup 6 Streptococcus pneumoniae isolates from children in China has identified no antibiotic-resistant clones, leading the authors to speculate that the isolates may be under antibiotic selective pressure. The findings are important because serogroup 6 is one of the most common causes of invasive pneumococcal disease in unvaccinated populations, say Yonghong Yang (Beijing Children’s Hospital Capital Medical University, China) and co-authors in BMC Infectious Diseases. Yang et al investigated the population biology of 255 strains of serogroup 6 S. pneumoniae isolated from paediatric nasopharyngeal specimens collected between 1997 and 2011. Serotypes were identified using the Quellung reaction and polymerase chain reaction; type 6A was the most prevalent, accounting for 46.7% of isolates, followed by 6B-II (25.8%), 6B-I (19.6%), 6C (6.2%) and 6D (1.8%). Multilocus sequence typing revealed 58 distinct strains, the most common of which were ST982 (23.1%), ST90 (14.7%) and ST4542 (7.6%). The researchers identified eight new sequence types and...