The pink/orange stains in the toilet are most likely bacteria called Serratia Marcescens. This type of bacteria is most frequently observed in toilet bowls, on surfaces in shower stalls, inside dishwashers, on tiles, in sinks, and in pet water dishes.
The bacteria will grow in any moist location where phosphorous containing materials or fatty substances accumulate. Serratia can grow in toilets where the water is left standing long enough for the chlorine residual disinfectant to dissipate. Serratia will not survive in chlorinated drinking water. To remove the bacteria in your toilets, clean them with bleach.