People are a significant source and the most unpredictable vector of microbiological contamination. Microorganisms are always present on hair and skin, which are shed into the surrounding environment. With more movement, more microorganisms are shed.
Concentrations of microorganisms are found in the nose, throat, mouth, anal and genital regions, and may be dispersed by breathing, coughing, sneezing, talking, flatulence and hand contact.
The most likely types of microorganism traceable to natural shedding are
Staphylococcus spp. and Micrococcus spp. Propionibacterium spp. and other coryneforms are unquestionably of human origin but, although periodically identified in failed sterility tests, are hardly ever isolated in environmental monitoring programmes. This may be due to their sensitivity to oxygen and to light limits, the length of time they can survive in air, but most likely by direct transfer from personnel without air being involved as a vector.
Staphylococcus spp. and Streptococcus spp. may be traceable to the nose and throat, Enterobacteriaceaea to the anal and genital areas. Yeast may be traceable to nose, throat or genitals.
Contamination from people is generally controlled by two means.
"Packaging the Personnel"
Personnel who work in clean rooms must be provided with garments suitable for the type of work and clean room. In high-grade, aseptic clean rooms this usually means that all garments are sterile, made from bacteria-retentive fabrics, nonlinting, and leaving as little as possible uncovered skin. In support areas it is unnecessary to have such stringent garment control. No matter how severe the restrictions placed on garments, they are a compromise — personnel have to breathe, perspire, move, see, hear, and so on.
The logic of particular restrictions is always challengeable: "Why do I have to wear a head cover when I shave my head each day? Look, that guy over there has bushy eyebrows and you don't ask him to cover them!"
Informed common sense should prevail.
Most people are well intentioned. When they know that there is a correct way of doing things, they usually do it that way. When they understand the reason behind a particular way of doing things, they are even more likely to do it in the proper way. Managers in the pharmaceutical industry are responsible for training (educating) personnel in asepsis, in proper ways of changing into their clean-room garments without contaminating them, the change rooms, the clean rooms, and in proper behaviour in the clean rooms.
Some pharmaceutical manufacturing companies claim to restrict personnel from clean rooms if they have been shown to carry pathogenic staphylococci or streptococci in their throats or noses. It is very important that personnel with symptomatic medical conditions leading to excessive shedding or dissemination of microorganisms, e.g., coughs, colds, flaking eczema, etc., be restricted from clean rooms.
The attempt to restrict nonsymptomatic carriers is a different issue of complexity. Why should nonsymptomatic carriers of Staphylococcus aureus in their noses be more of a risk to sterile products than nonsymptomatic carriers of Staphylococcus epidermidis on their skins (as most people are)?
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