Mycoplasma pneumoniae, a cause of pneumonia, as its name suggests, is also implicated in reactive arthritis.

ECONOMIST: Bugged by disease

Chlamydia trachomatis also causes blindness, while its cousin, Chlamydia pneumoniae, is implicated in childhood asthma and adult emphysema.

ECONOMIST: Bugged by disease

Penicillin is now useless against one-third of all Streptococcus pneumoniae, a common cause of pneumonia, meningitis and ear infections.

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But perhaps the most worrying of all these findings is the suspected link between Chlamydia pneumoniae and atherosclerosis (hardening of the arteries).

ECONOMIST: Bugged by disease | The

However, the researchers detected the same resistant S. pneumoniae strains in siblings of attendees, suggesting that resistance could easily spread beyond the confines of a centre.

BBC: Nursery

Those involved in the study were also tested for Chlamydia pneumoniae, which causes lung diseases, and Mycoplasma pneumoniae, which can cause a mild form of pneumonia.

BBC: Herpes virus linked to dementia

Mycoplasma pneumoniae also appears to be involved in asthma.

ECONOMIST: Bugged by disease