Natural Rocks are Richer in Microbial Communities than in Playgrounds

Fig 1. The gene copy numbers sampled from dust and dirt from artificial rubber mats (blue) and natural rock (red). The solid outline boxes are 16S rRNA gene copy in all samples and the dotted boxplots are paired samples. The mean is the midline and the upper and lower hinges are the minimum and maximum in order. This figure shows that natural rocks have a higher gene copy than the sampled rubber mat from playgrounds. https://doi.org/10.1128/spectrum.01930-24

The playground environment stresses microbial communities that contribute to the risk of immune-mediated diseases. Children are more at risk of infection by poor microbial communities in playgrounds. In this study led by Juulia Manninen and other researchers, tested a total of 20 dirt and dust samples gather from 9 natural rocks and 19 playgrounds in Finland cities of Helsinki and Lahti. The natural rocks from dry natural habitats were used in this study were biotite paragneis, microcline granite, or quartzite. The rubber mats were made of steryene-buadiene and ethylene propylene diene monomer rubber. In their experiments they analyzed bacterial communities by using Illumina MiSeq 16S rRNA gene metabarcoding. They found that the 16S rRNA gene copy numbers were higher than the sampled rubber mats. Additionally, there was a more pronounced contrast when the mean values were in paired samples as shown in Fig.1. The importance of this study is to understand and be aware that playgrounds with poor microbial communities are creating avoidable situations that can be managed with proper strategies. Such as introducing rich organic soil and a diversity of vegetation. This certain introduction can increase the quality of children's immune system. Some concerns regarding this situation are that children being affected with immune-mediated diseases can develop antibiotic resistance from the antibiotics they are prescribed. Antibiotic resistance will become a challenge for treating immune-mediated diseases in the future.

Original article:

Manninen J., Saarenpaa M., Roslund M., Galitskaya P., Sinkkonen A. 2025. Microbial communities on dry natural rocks are richer and less stressed than those on man-made playgrounds. Microbiology Spectrum 13(5):1930 https://doi.org/10.1128/spectrum.01930-24