Long interruption of production represents the largest threat from political turmoil to the financial stability of oil and gas companies with operations in the Middle East and North Africa (MENA) but remains unlikely, an international credit-reporting agency says.A secondary risk, nationalization of assets by successor regimes in countries now experiencing unrest, is a "remote scenario," although contract renegotiations by successor regimes remains possible, according to Fitch Ratings, New York and London.A recent Fitch report covering North American companies with operations in the MENA region said credit pressures from unrest in Egypt, Libya, and other countries of concern are...