Seasonal changes in bacterial and fungal concentrations in floor dust from Lublin region homes

摘要

Numerous studies have demonstrated that floor dust can play a role of bacterial and fungal depository in indoor environments. Typically, microbial species originate from sources other than the dust itself like the outdoor environments, occupants and pets. Most notably indoor sources of bacteria and fungi are biological corrosion of building materials, house plants, food and HVAC systems. This study presents seasonal changes in bacterial and fungal concentrations in floor dust from 50 households located in Lublin area, Poland. During one year survey, floor dust samples were collected twice a month from vacuum cleaner bags. No moisture or mold problems were reported in studied houses, and the residents did not use any air cleaners. Moreover, temperature and relative humidity in studied households were recorded during the measurements. The bacterial and fungal concentrations were determined by the dilution plate method. Additionally, the bacterial and yeast strains were taxonomically identified after Gram staining based on their morphology and biochemical analytical profile index (API) tests. Filamentous fungi were identified according to their morphology using identification keys. Average concentrations of bacteria varied from 1.3x104 to 2.4x106 CFU/g dust and for fungi from 1.1x104 to 6x106 CFU/g dust, respectively. Microbial concentrations varied significantly between different seasons and hence the similarity of samples within a home was mainly low. The most commonly isolated cultivable bacterial genera included Bacillus, Staphylococcus, and Pseudomonas. Fungi were dominated by Penicillium, Aspergillus and Penicillium sp.