## 3 Results and Discussion
### Microbial Risk Assessment at the Museum Palace in Wilanow
#### 3.3.2 Putative Bacterial Pathogens  
While human-to-human transmission of pathogenic bacteria is strongly dependent on a pathogen's biology, many studies emphasize that the environment and its characteristics, such as indoor/outdoor location, active/passive ventilation, heating, humidity, and temperature, play an important role in pathogen viability [18; 19; 48]. Above all, direct human contact is the main driving factor for both viral and microbial infections. Museums and other institutions of cultural heritage can be considered as hot spots of increased biological air contamination due to their high human traffic. Therefore, their regular testing is of utmost importance. Published studies investigating microbial air contamination usually focus on bacteria known to be etiological factors of respiratory diseases, such as _Mycobacterium tuberculosis_, _Legionella pneumophila_, _Pseudomonas aeruginosa_, or members of the _Staphylococcus_ genus [49; 50; 51]. In this study, we detected a relatively high number of representatives of the _Pseudomonas_ and _Staphylococcus_ genera (Figure 3). While _Pseudomonas_ spp. host many species that are able to colonize a wide range of niches, _Staphylococcus_ spp. are instead associated with a multitude of mammalian infections [52; 53]. Human pathogens can also be found in both genera, including: (i) an opportunistic pathogen _P. aeruginosa_, which is a common multidrug-resistant bacterium that causes severe infections, especially in patients with cystic fibrosis [54]; (ii) _Pseudomonas mendocina_, an emerging pathogen that causes mainly nosocomial endocarditis and meningitis [55]; (iii) _Staphylococcus aureus_ and _Staphylococcus epidermidis_, which are known to cause various skin and soft-tissue infections [56]. Moreover, amongst the detected genera, some can host opportunistic human pathogens, as is the case for the _Chryseobacterium_ genus. [PERSON] et al. described several serious infections caused by _Chryseobacterium indologenes_, a bacterium that is usually found in soil and water [57]. In order to quantify the applicability of the used growth media for the detection of human pathogens in museums, we conducted a systematic literature review, as described in Section 2.5, to identify genera that potentially contain human pathogens. This analysis revealed that 64 out of 130 genera detected in this study contained bacterial species reported to be human pathogens (Table 3). Despite the very high contribution of genera containing human pathogens--49.23%, it should be noted that most of them are opportunistic pathogens, which are mostly dangerous, specifically for immunocompromised individuals. Table 3 shows that the FA and R2A media detected up to 46 genera containing human pathogens, while NA--42, LB--40, BHI and BA--37, and YEA only 19. These results were in line with general genus recovery rates presented in Table 2, showing that the media (FA and R2A) capable of recovering the highest number of different bacterial genera were also suitable for the detection of species that are potentially pathogenic to humans. It is also important to highlight that one of the dominant genera found in the Museum of King John III's Palace at Wilanow, namely, _Acinetobacter_, contains two clinically important pathogenic species, namely, _A. baumannii_ and _A. Iwofii_, which are both often characterized by their ability to form complex biofilms that reduce their sensitivity to many antibacterial agents, such as antibiotics [58; 59]. Although _A. baumannii_ is rarely found outside hospitals, it is still possible that a museum microclimate, with its stable temperature and humidity, may provide suitable conditions for its development.