SOFIA (Bulgaria), October 25 (SeeNews) - International rating agency Standard & Poor's (S&P) said on Thursday it has affirmed a BB- long-term issuer credit rating on the central Bulgarian city of Karlovo on a stable outlook. "The rating is constrained by Karlovo's continuing operating deficit and limited fiscal flexibility in the face of operating-expenditure pressures and infrastructure investment needs. [...] In addition, the impact of upcoming public finance reform is unclear, given continued uncertainty about its content, with no details having been made to the public to date," S&P credit analyst Marcin Gdula was quoted in a statement as saying.