Healthcare-associated infections (HAI) are commonly defined as adverse events resulting from the provision of healthcare. The reduction of risk arising from the spread of pathogenic microorganisms in the hospital environment is a considerable challenge in the context of the proper functioning of the medical services sector. The financial costs of hospitals resulting from HAI are a serious problem for the Polish healthcare system. The spread of strains with a high level of drug resistance in individual hospitals is associated with the local epidemiological situation. In 2015-2017, there was a high increase in the number of infections caused by New Delhi strains. The highest increase due to this strain occurred in Mazowieckie and Podlasie provinces. The dynamics of infection caused by New Delhi strains throughout Poland in 2015-2016 indicated an increase of 278.7%. In 2017, the phenomenon of antibiotic abuse in all regions of Poland was 24% higher than the EU average. One of the reasons is the insufficient number of diagnostic tests ordered by both general practitioners and doctors representing hospital care. In 2016-2017, the average number of microbiological tests in diagnosing hospital infections performed annually within the entire territory of Poland was 50% lower than in European Union countries and the number recommended by WHO. Increased, and at the same time inappropriate antibiotic therapy led to a build-upof drug resistance among bacterial species of significant clinical importance. The current epidemiological situation imposes the necessity for constant HAI control and broadly understood rationalization of the guidelines of hospital antibiotic policy.

Although the evaluation of air quality in the residential and office rooms has been significantly developed in recent decades, the issues associated with securing the air quality requirements in nurseries are still not well recognised. This study presents the results of tests regarding the physical and microbiological properties of air in selected rooms of a nursery, including the alternatively variable way of rooms ventilation. The experiment was conducted in four different rooms from the 20th of November 2017 to the 16th of April 2018. The constant measurements of basic parameters of physical air quality in rooms and outside as well as the measurements of microbiological and particulate matter contaminations were conducted in the chosen days of the analysis. The results have confirmed the unsatisfactory air quality in the rooms dedicated to small children. Modernisation of the ventilation system, from a natural one to the supply-exhaust ventilation, has lead to an improvement of physical property of the air, but it did not significantly improve its microbiological quality. Our research indicates that the controlled air flow, method of cleaning the premise and health condition of the children may have a great influence on the physical and microbiological quality of the air.

This article presents the current and important results of bioaerosol studies which allow for the comparison of microbial contamination of air in 11 wastewater treatment plants (WWTPs), which differed in terms of capacity from 350 to 200,000 m³/day. The abundance of mesophilic bacteria, M+ and M− Staphylococcus, Pseudomonas fluorescens, Actinobacteria, coliform and psychrophilic bacteria, and microscopic fungi was determined. Additionally, the air temperature, relative humidity, wind velocity, and direction were also analyzed at each research station. The obtained very numerous results of bioaerosol and climate parameter studies were subjected to statistical analysis. The results regarding the minimum, maximum, and median abundance of the studied bacteria and microscopic fungi at 11 WWTPs and in background studies at control stations were presented in tables. Additionally, basic descriptive statistics for all studied microorganisms at specific seasons were presented. It was established that at the areas of WWTPs, the microscopic fungi were present that the highest concentrations (ranging from 0 to 1,148,530 CFU m⁻³), followed by psychrophilic bacteria (ranging from 40 to 225,000 CFU m⁻³) and mesophilic bacteria (ranging from 0 to 195,000 CFU m⁻³). The novel elaboration of bioaerosol study results based on cluster analysis and determination of a dendrogram allowed to compare the studied WWTPs. The similarity was decided based on the type of studied microorganisms and their dominance and abundance, while no similarities were observed in terms of capacity. In order to investigate the relation between the abundance of bacterial groups as well as microscopic fungi and microclimatic parameters (air temperature and humidity), a calculation of Spearman’s range correlation coefficients was conducted.

This study presents the results of bioaerosol analyses conducted in the area of 9 wastewater treatment plants (WTTPs) in the Wielkopolska Region (Poland) with different capacities (from 500 to 200,000 m3/day). The abundance of mesophilic and psychrophilic bacteria, Staphylococcus, Actinobacteria, Pseudomonas fluorescens, coliform bacteria, and microscopic fungi in different plant sites and the control site were analysed. Microscopic fungi exhibited the highest contribution to air contamination and their highest median value was found in WWTP No. 5, which reached 6,700 colony forming units (CFU/m3) of air. Psychrophiles and mesophiles were the most abundant bacterial groups. It was established that the highest concentration of bioaerosols was observed during the mechanical treatment of wastewater at sewage sludge treatment sites and near bioreactors. The Rav parameter, which represents the ratio of average annual microbial abundance in the air to the average annual microbial abundance in the background at the control site, was a very good indicator of air contamination rate. This parameter may be analysed with respect to bacteria (Rav B), microscopic fungi (Rav F), and all microorganisms (Rav M).

Introduction: Clostridium difficile spores, due to their ability to adapt to adverse conditions in a hospital environment, cause enormous difficulties associated with the effective decontamination of surfaces and equipment. Elimination of this pathogen is possible through effective...

Dissatisfaction with indoor air quality is common even in relatively new or renovated Polish school buildings. To improve air quality in educational buildings, portable devices have seen increased use, for which manufacturers guarantee a high level of indoor air purification. However, their optimized operation largely depends on their correct use. The aim of this article was to determine the effectiveness of air purification in a primary school using an air purification device with an analysis of the classroom indoor air quality (IAQ). Two criteria were used, microbiological and particulate matter concentration. Measurements were made before device installation and during its continuous operation, and before and after lessons on chosen days. Measurements related to IAQ did not detect clear differences in the analyzed measurement periods. For microbiological contamination, in the morning before lessons, the total count for all bacteria and microscopic fungi was definitely lower than after lessons. Comparing the periods before and after device installation, no clear tendency for reducing the bacteria count or microscopic fungi occurred during air purifier operation, nor was there any noticeable trend in the reduction of particulate matter. There was no improvement in air quality in the classrooms during the operation of the purification devices.