The present study is aimed at evaluating microbiological air pollution in libraries, cafeterias and selected classrooms of two schools in Bydgoszcz city, northern Poland and determining the antibiotic resistance of Staphylococcal strains isolated from the indoor air. One of the investigated schools (School A) is located in the very center of the city, in the vicinity of a park, among old houses and stone-lined streets, while the other (School B), among modern residential buildings, close to a street with heavy traffic. In each school, air samples were collected in the morning, always from all three sampling sites, using the MAS-100 sampler. Selective growth media were used for bacteria and mold isolation and quantifying analysis. The antibiotic resistance of the isolated mannitol-positive staphylococci was assessed using the disc diffusion method in accordance with EUCAST recommendations. The highest mean concentration of heterotrophic bacteria was recorded in the cafeterias: 884 CFU m⁻³ in School A and 1906 CFU m⁻³ in School B. Molds were the most abundant in the library and cafeteria in School B, where their average concentration exceeded 300 CFU m⁻³. Cladosporium and Penicillium species prevailed, while Fusarium, Acremonium and Aspergillus were less abundant. Airborne mannitol-positive staphylococci were recorded at low concentrations, ranging from 6 to 11 CFU m⁻³ on average. According to the taxonomic analysis, Staphylococcus aureus isolates were the most abundant in both schools, followed by S. xylosus, S. haemolyticus and S. saprophyticus. The antibiograms indicated that resistance to erythromycin was common in 62.5% of the isolated staphylococcal strains. Levofloxacin and gentamicin were the most effective antibiotics. No multidrug-resistant strains were identified.

中文翻译：

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两所学校选定房间中生物气溶胶的多样性和分离的葡萄球菌菌株的耐药性（波兰比得哥什）：一个案例研究

本研究旨在评估波兰北部比得哥什市两所学校的图书馆，自助餐厅和部分教室中的微生物空气污染，并确定从室内空气中分离出的葡萄球菌菌株的抗生素耐药性。其中一所被调查学校（学校A）位于城市的正中心，在公园附近，在老房子和石砌的街道之间，而另一所学校（学校B）在现代住宅建筑中，靠近一条交通繁忙的街道。在每所学校中，总是使用MAS-100采样器在早晨从所有三个采样点采集空气样品。选择性生长培养基用于细菌和霉菌的分离和定量分析。分离的甘露醇阳性葡萄球菌的抗药性是根据EUCAST推荐使用椎间盘扩散法评估的。食堂记录的最高异养细菌平均浓度为：884 CFU mA学校中的⁻³和B学校中的1906 CFU m ^-3。霉菌在B学校的图书馆和自助餐厅中含量最高，其平均浓度超过300 CFU m ^-3。枝孢属和青霉菌占优势，而镰刀菌，顶孢菌属和曲霉菌则较少。空气中甘露醇阳性葡萄球菌的浓度很低，平均范围为6至11 CFU m ^-3。根据分类学分析，金黄色葡萄球菌分离株在两所学校中含量最高，其次为木糖链球菌，溶血链球菌。和腐生葡萄球菌。抗菌素谱图表明，在分离的葡萄球菌菌株中，对红霉素具有抗性是62.5％。左氧氟沙星和庆大霉素是最有效的抗生素。未鉴定出耐多药菌株。