Microbial evaluation of sandboxes located in urban area

Area of Science:

• Environmental microbiology
• Public health
• Pediatric safety

Background:

• Sandboxes in urban housing estates are potential reservoirs for microbial contamination.
• Assessing sandbox safety for children requires understanding the diverse microbial communities present.

Purpose of the Study:

• To evaluate the bacteriological and mycological pollution of sandboxes in urban housing estates.
• To compare microbial contamination levels between sandboxes in fenced and unfenced areas, and near/far from trees.
• To assess the adequacy of traditional fecal indicator bacteria for evaluating sandbox microbial safety.

Main Methods:

• Analysis of sand samples from urban sandboxes using cultivation and fluorescence in situ hybridization (FISH) methods.
• Quantification of Heterotrophic Plate Counts (HPC22, HPC37), Enterobacteriaceae, Escherichia coli, Enterococcus spp., Staphylococcus spp., and Clostridium perfringens.
• Identification of dominant bacterial genera and enumeration of molds and yeasts.

Main Results:

• High microbial loads were detected, with culture-independent methods yielding results 2-4 orders of magnitude higher than cultivation.
• Pantoea spp. and Enterobacter cloacae were the most abundant Enterobacteriaceae; Escherichia coli was detected infrequently.
• Potentially pathogenic Salmonella spp. were isolated even in the absence of E. coli, and Staphylococcus spp. were ubiquitous.
• Molds (Aspergillus, Penicillium) and yeasts (Trichosporon) were also prevalent.
• Sandboxes in fenced estates and those away from trees exhibited lower pollution levels.

Conclusions:

• Sandbox microbial pollution is complex and includes potentially pathogenic bacteria beyond fecal indicators.
• Environmental factors like fencing and proximity to trees significantly impact sandbox contamination.
• Relying solely on fecal bacteria and parasite egg counts may underestimate microbial risks in children's play areas.