It is widely established that drains are reservoirs for microbes and antibiotic residues. It is also clear that microbes in drains and pipes adhere to the surfaces of drains and drain age pipes as microbial biofilms, creating a complex ecosystem of different microbes that are fed by organic and inorganic matter. Drains act as cradles to the emergence of bacteria armed with abilities to resist multiple antibiotics. The development of resistance is probably enhanced at hospitals due to the fact that more bacteria and more antibiotics are flushed down the drains due to the very nature of hospitals constantly caring for numerous different patients that are ill and treated with antibiotics.
Thus, biofilm in building drains, not properly maintained, have the potential of spreading even more resistant bacteria. Numerous studies stress the importance of a physical barrier between drainage systems and surroundings. As shown in the SARS outbreak at Amoy Gardens, harmful biologic aerosols can enter the ventilation system from exposed drains and be spread to all the other connected rooms igniting a fearsome spread. It is essential that drainage systems must be completely tight and intact where openings have physical barriers.