Potential Health Risk of Exposure to Microbial Contaminants in Settled Indoor Dusts (SIDs) from a Polytechnic Environment

Dust particulates are solid, settle on the surface of objects and harbor a range of largely benign microbes, some of which are beneficial or pathogenic. Indoor dust exposure is a growing public health concern and needs a wide range of attention. The study aims to examine the microbial contaminants in indoor dust from a polytechnic environment. A total of ten (10) composite settled dust samples were collected from selected sampling sites in Moshood Abiola Polytechnic (MAPOLY), Abeokuta, Ogun State, Nigeria. Samples were collected, labeled and transported to the laboratory for microbial analysis using standard microbiological techniques. The findings revealed that the dust contained six (6) bacterial species ( Escherichia coli, Enterococcus sp., Staphylococcus aureus, Staphylococcus epidermidis, Bacillus subtilis and Pseudomonas aeruginosa) which can be grouped into gut-associated bacteria (Enterococcus sp. and E. coli) suggesting potential fecal contamination, skin-associated bacteria (S. aureus and S. epidermidis), and soil-associated bacteria (B. subtilis and P. aeruginosa), suggesting contamination from outdoor dust particulate. Also, isolated are nine (9) fungal species (Aspergillus niger, A. nidulans, A. terrus, Rhizopus sp., Candida sp., Mucor sp., Penicillium sp., Conidiobolus sp., and A. flavus). The fungal isolates were primarily soil and dust dwellers, which must have evolved from the outside environments. Although they are considered non-pathogenic, they can be harmful to occupants with compromised immune systems. In conclusion, the presence of the isolates indicates dust contamination and, therefore, is a public health concern.