Potentially Pathogenic Bacteria in Urban Indoor Air Assessed by Culture‐Dependent and Culture‐Independent Quantitative PCR Methods: A Study of Public Service Buildings in Poznań, Poland

Potentially pathogenic airborne bacteria may pose a risk to human health, yet their prevalence in public service buildings remains largely unknown. In this study, we detected and quantified the most common potentially pathogenic bacteria in the air inside public service buildings (schools, universities, a pharmacy, and a medical clinic) in Poznań, a large city in Poland, using both culture‐based and culture‐independent PCR methods. The total number of bacteria determined by culturing reached 1.1 × 10 4 CFU/m 3 , while 16S rRNA gene copy number analysis indicated 2.4 × 10 5 bacteria/m 3 . Indoor air was contaminated with numerous bacterial species, including Pseudomonas aeruginosa , Escherichia coli , Enterococcus faecalis , Staphylococcus aureus , and Klebsiella pneumoniae . Among species‐specific targets, the highest gene copy number determined by the culture‐independent approach was 3.4 × 10 4 copies/m 3 for the regA gene of P. aeruginosa . The results demonstrate the need for routine microbiological monitoring of indoor air quality in public service buildings.