[Hygienic and bacteriological comparative studies in 50 hospitals. I. Methods and aim of microbiological monitoring...

Within a period of a year, environmental examinations were carried out in 50 hospitals selected at random in Rheinland-Pfalz with a view to determining the effective conditions, mainly in such risky areas as operating theatres, delivery rooms, intensive-care units and neonatal wards. In this first report the method is described. Such investigations are based on a detailed interrogation of the staff, and local inspection. As is evident from the extract from the questionnaire, the investigation was mainly concerned with details of the functional procedure and the implementation of measures of hospital hygiene. During the subsequent inspection of the rooms, we had the various procedures demonstrated to us. The testing of the sterilisation effect of all 461 programmes of the sterilisers was carried out with spore earth in accordance with DIN 58947. Staph. aureus and Bac. mesentericus spore preparations in accordance with DIN 58949 were used to check the thermal bed-disinfection apparatus. For the determination of the qualitative and quantitative contamination of persons, we employed 2321 sponge-type impression preparations and 8790 "Rodac plates" for the surfaces of floors and furniture. Throat swabs were taken from each of the 831 persons examined, and checked for the presence of pathogens. 2848 blood agar plates were exposed for one hour to ascertain the sedimenting air germs. Although this method is not suitable for determining the germ content per cubic metre of air, it nevertheless furnishes a good idea of the prevailing conditions without involving much work. As part of such environmental examinations, it is very important to determine the contamination of liquids from buckets, disinfecting solutions, bottles from oxygenators, air humidifiers etc. When the samples contained growth-inhibiting additives, we immediately mixed them with an inactivation medium. In the laboratory, blood and endo-agar plates were inoculated with the concentrate and dilutions. In addition we enriched the sediment in 2% sugar bouillon. All culture media were incubated for 48 hours at 37 degrees C. Subsequently we counted the colonies and differentiated in accordance with the usual biochemical or, if required, serological methods. Further reports will discuss the results of this investigation.