Most life-threatening meningitis and septicaemia in the UK is caused by the meningococcal bacteria.
Meningococcal bacteria are classified according to structural differences in certain components. The serogroup, e.g. A, B, C, W or Y, is defined by the type of sugar coat, or capsule, that surrounds the bacteria.
Meningococcal bacteria can also be classified according to certain parts of their genetic make-up. This type of classification is known as Multi Locus Sequence Typing (MLST) and it is based on similarities between seven ‘housekeeping’ genes within the meningococcal genome. The advantages of classifying bacteria in this way is that it can provide information about how bacteria are evolving over time and the information can easily be shared between laboratories and researchers. This is one of the reasons why our genome library
is such a useful resource.
Genetic sequences which are identical across the seven housekeeping genes will belong to a given sequence type (ST). Meningococcal bacteria belonging to ST-11 have been identified as especially virulent and have been associated with outbreaks that particularly affect healthy people in their prime, namely teenagers and young adults.