Airborne coagulase negative staphylococci produced by a sewage treatment plant

Since some coagulase-negative staphylococci species are involved in clinical and environmental situations, the authors carried out a study on the spread of these bacteria in the air of a sewage treatment plant. For these purposes a total of 196 samples were taken from 16 sampling stations, 11 during the day and 5 at night (only at 4 points), using the settle plate technique. Altogether 13 species of coagulase negative staphylococci were isolated: S. haemolyticus, S. xylosus and S. cohnii were particularly common. Station no. 2 (an area almost always kept closed containing the fine screens) was found to be the most contaminated. The presence of coagulase negative staphylococci was favoured by high temperatures and low humidity. No differences were found due to variations in wind speed and direction or between day and night.