We report on a partially circular X-ray surface brightness discontinuity found at about 55 kpc from the centre of Abell 2199 with Chandra X-ray observatory observations .
Unlike cold fronts found in other clusters , the feature shows no significant temperature change across it but has an apparent density jump .
We therefore identify it as a weak isothermal shock associated with the central AGN and the inflation of its radio bubbles , as found in the Perseus cluster .
We examine a similar feature at 40 kpc radius found by Mazzotta et al in 2A 0335+096 , and conclude that it too may be an isothermal shock .
The change in density if these are shocks implies a Mach number of \sim 1.5 .
If the isothermal nature of these features is confirmed by deeper observations , the implication is that such shocks are common in clusters of galaxies , and are an important mechanism for the transport of energy from a central supermassive black hole into the cluster core .