Diversity Of Culturable Bacteria On Natural Vs Artifical Fabrics

摘要

Bacterial sampling of clothing worn by a class of undergraduate microbiology students was performed over the course of one month. Microorganisms were cultured on nutrient agar, visually distinct colonies were subcultured, and subcultured colonies were tested for alpha haemolyic properties. Significant differences were found between the number of visually differentiable types of colony forming units on natural and artificial textiles, with mean diversity of cfus on artificial textiles exceeding those on natural by a factor of 2.3. Significant differences in the number of organisms capable of alpha haemolysis were also noted, with mean levels of such organisms on artificial textiles exceeding those on natural by a factor of 3.7. Introduction Clinical practices are important in reducing rates of nosocomial infection. Many studies have been done related to patient-centered aspects of nosocomial infection. For example, it is known that adherence to hand washing protocols results in reduced rates of nosocomial infection (1). Fomites also have the potential to transmit infection. Studies have shown that approximately 25% of the white coats worn by health care workers carry Staphylococcus aureus, including methicillin-resistant strains of the organism (2,3). Neckties have also been implicated as potential vectors, although conclusions as to the risks they present vary (4,5). They are no longer recommended for clinical wear in the UK (4). The above referenced studies examine fomites such as white coats and neckties without breakdown as to material composition or microorganismal diversity. There is evidence to suggest that the type of textile used in clothing has a significant impact on the type and number of microorganisms that colonize the object. Microorganism populations have a significant impact on infection. Understanding these populations may allow superior control of nosocomial infections.It is known that polyester and acrylic fibers bind Gram negative and Gram positive organisms at ratios exceeding 80%, whereas cotton fibers bind these organisms at ratios less than 10% (6). Synthetic textiles have been shown to collect more bacterial mass than cellulose-based textiles (7). It has also been shown that while cellulose-based textiles are mostly colonized by bacteria normally found in human sweat, such as members of Propionibacteria, Corynebacteria, Staphylococcus and Streptococcus, while synthetic textiles are frequently colonized by genera that are not found in human sweat (8,7).Studies addressing the type and quantity of bacteria that colonize textiles relative to their material composition have previously been done on textile and fiber samples under strictly controlled laboratory, ie in vitro conditions, usually with known quantities of microorganisms being artificially introduced to the fabric sample. This study looks at the relationship between the diversity of organisms on clothing and the type of material of which the clothing is composed under more typical, ie in vivo conditions, wherein the textiles sampled were worn by human beings during normal use, and acquired populations of microorganisms under real world conditions. Materials and Methods In order to test if clothing composition affected the number of bacteria carried on that clothing, undergraduate students in a microbiology class at Illinois Wesleyan University examined the relationship between the number of organisms found on the cuffs of their classmates’ sleeves and the material of which the clothing was made. Study participants gave informed consent; samples were anonymized and records relating individuals to their samples were destroyed. Damp, sterile swabs were used to sample the bottom-most two inches of the sleeves of participants every class period. Material composition of the garments was recorded. If clothing was composed entirely of plant or animal-based fibers, it was recorded as a “natural fiber”. If clothing was composed all or in part of artificial