Indoor bioaerosols in hospitals influenced by air conditioning

Ricardo Gonzalez

(Figure 1) Bacterial colony formation 

(Figure 2) Fungal colony formation

Figure 1. represents how much bacterial colony formed in units per cubic meter (CFU/m^3) in hospitals. (blue) represents without an HVAC system, (orange) use of conventional HVAC, and (grey) with the use of an enhanced HVAC system. This represents how the different types of filters and quality had an effect of the presence of bioaresoles. 

Figure 2. represents the same ting but this is fungal colony formation

    Hospitals around the world are essential for human health but as a consequence, everyone is mostly sick, causing many bioaerosols to roam freely. The objective of this experiment is to evaluate the relationship between HVAC systems and bioaerosol concentration between different hospital rooms. As to when it comes to results, HVAC systems that are enhanced effectively remove bioaerosols but this is predictive, since these are restricted areas, which are meant to be clean and concise throughout. This study was influenced because of the coronavirus disease in 2019 HVAC systems are known to speed up the change and direction of indoor airflow which researchers suspect the HVAC systems may increase the SARS-CoV-2 infection back in 2019 along with current viruses and bioaerosols infectious diseases. The results come to prove that conventional HVAC systems, effectively remove bacteria and fungi from indoor air and enhanced HVAC systems were a lot more effective than conventional HVAC systems in this study. The figures for bacterial colony formation shows that inpatient facilities without HVAC systems had a CFU/m^3 of 356.45 compared to restricted areas without HVAC system where the value of CFU/m^3 was 387.50. If you are to compare this with the values of enhanced HVAC systems, the inpatient facility would have a 20 CFU/m^3 value and restricted area of 36.12 significantly decreasing the amount of bioaerosols in the system in both environments. Overall study concluded that the infection risk associated using HVAC systems did not increase infection risks during the pandemic. All that HVAC systems do in hospitals is to simply reduce the indoor concentrations of bioaerosols which was concluded at the end of the research. 

Original article:

Dai, Rongchen, et al. “A Systematic Review and Meta-Analysis of Indoor Bioaerosols in Hospitals: The Influence of Heating, Ventilation, and Air Conditioning.” PLOS ONE, vol. 16, no. 12, 23 Dec. 2021, p. e0259996, https://doi.org/10.1371/journal.pone.0259996. Accessed 24 Apr. 2022.

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Antibiotic Resistant Bacteria in Compost?

 Amoxicillin Resistance During Composting 

by: Diana Tarver

Figure 1. Dynamic changes of (A)Amoxicillin-resistant bacteria and (B) Amoxicillin-resistant bacteria during composting (days) and how many bacteria were counted. (CK) is the control group, regular compost bacteria with no amoxicillin. 

Amoxicillin is the most used beta-lactam antibiotic as it is used for both humans and livestock. This changes their microbiome which in turn, affects the manure microbiome with possible antibiotic-resistant bacteria. Studying the environmental and human health risk of antibiotic resistant bacteria being transferred so close to our food sources particularly composting, we love using compost even for our backyard gardens, buying manure can be an important part of the microbiome of compost but as stated antibiotics change manure microbiome. Such is that a study carried out by Ning Liu and colleagues looked into the environmental drivers and interactions of bacteria in compost. Samples of pig manure were taken from a pig farm in Shunyi District with the assurance that no antibiotics were used from sampled pigs. Amoxicillin was mixed in by researchers along with a control group with no antibiotic. Their results found good news in that the exposure to composting reduced the availability of heavy metals and amoxicillin reducing the pressure for bacteria to need resistance to antibiotics. Figure 1. This data shows a drastic drop in amoxicillin in both A and B charts, the control group (CK) even starting off with low numbers stabilized the amoxicillin resistant bacteria. This goes to show microbiomes are incredibly powerful by using organic waste products we could promote resource recovery in agriculture. 

Original article:

Liu, N., Li, G., Su, Y., Zhao, Y., Ma, J., & Huang, G. (2023). Environmental drivers and interaction mechanisms of heavy metal and antibiotic resistome exposed to amoxicillin during aerobic composting. Frontiers in Microbiology, 13. https://doi.org/10.3389/fmicb.2022.1079114 

PAE: Plastics Affect on the Enviornment

 

Figure shows conjugation transfer experiments between the donor and the recipient (A), conjunctive transfer with and between genera that is exposed to DMP at different concentrations (B), relative abundance of transconjugant community (C) in conjugative transfer of RP4 plasmid and wastewater microbiota.

In the manufacturing and processing of plastic products phthalate esters (PAEs) are used as plasticizers to enhance the flexibility and durability of the polymers. But PAEs have weak interactions which causes the toxic PAEs to release from the plastic; which can server risks environmental and ecological risk. PAEs can accumulate in the aquatic environments which can then be consumed in the human body by drinking water and foods thus causing diseases like cancer and abnormal reproductive hormones. Wu et al. (2023) have provided a study on how the microbial antibiotic resistance genes (ARG) behave in response to PAEs by using dimethyl phthalate (DMP) as a model toxicant. The donor and recipient strains were cultured in agar plates and incubated. Conjugate experiments was conducted where the donor strain and the recipient were mixed together, then spread on agar plates to grow and the cells were sorted after incubation. The results showed a strong interaction between the DMP molecules and the bilayer of the cell membrane, this causes the membrane lipid fluidity to decrease and the membrane permeability to increase which can favor ARGs.

Original Article:

Wu, J., Zhou, J.-H., Liu. D.-F.,Wu, J., He, R.-L, Cheng, Z.-H., . . . Li, W.-W. (2023, April 21). Phthalates Promote Dissemination of Antibiotic Resistance Genes: An Overlooked Environmental Risk. Enviornmental Science & Technology, 6761-6887. Retrieved from https://pubs.acs.org/doi/10.1021/acs.est.2c09491

Contamination of surfaces and air in hospitals by SARS-CoV2 patients

 By: Azeneth Ramos

The figure shows the location and percentage of sampled contaminated places inside hospital rooms due to SARS-CoV-2.

Being able to identify the level of risks from patients infected by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that pass onto environmental contamination by testing the air and surfaces surrounding hospitalized COVID-19 patients at different stages of illness. It's vital to understand the particle size distribution in air and environmental contamination of SARS-CoV-2 for the prevention of infections. Method one, done for air sampling in three out of the 27 airborne infection isolation rooms (AIIRS) detected positive SARS-CoV-2 PCR-positive particles, despite the changing of 12 air exhaust vent per hour. With air contaminated rooms also surface contamination was detected. A study done was for the presence of environmental surface contamination, Chia and colleagues concluded that higher contamination within the first week of illness was shown. Inside the room with environmental contamination, the floor resulted in being most contaminated, followed by the air exhaust vent, then bed rail, and lastly bedside locker. Chia and colleagues also concluded that SARS-CoV-2 is only able to remain alive in aerosols for up to 3 hours. Further investigation of findings in bigger numbers and in different settings to better grasp the factors affecting surface and air spread of SARS-CoV-2 and enforce effective prevention policies is important. 

Original Article:

Chia, P.Y., Coleman, K.K., Tan, Y.K. et al. Detection of air and surface contaminated by SARS-CoV-2 in hospital rooms of infected patients. Nat Commun 11, 2800 (2020). https://doi.org/10.1038/s41467-020-16670-2

The Existance of Leptospira spp. in Different Wetland Conditions Through the Year

Image A. The image on the right presents the location of the research study in South America near the Parana River 

Image B. The image presents the location of the sample sites 

    Leptospirosis is an infection of spirochaetes of the genus Leptospira. The infected cattle can spread the infection through urine which can infect other animals and humans in the contaminated environment. Sadly, Leptospirosis is capable of survival in numerous different environments, substrates, soils, sediments, and water. It was hypothesized that the amount of Leptospira in a wetland will be higher during higher water availability. The findings of Leptospira were based on water availability which they have learned to adapt to the aquatic environment conditions. Ecosystems with live-stock farming which are known for precipitation, flooding, and overflow can increase the transmission of Leptospira. It is important to know this information in order to prevent future outbreaks that can affect human health. In a study located in South America near the Parana River, 34 water samples and 12 sediment samples were taken from three different precipitation levels between November 2018 and November 2019 to which pathogenic species would be discovered. November 2018 was very dry with low precipitation levels and L. Kmetyu was identified. April 2019 was recorded to be very humid with higher precipitation levels L. kemetyi, L. mayottensis, and L. fainei were identified. In an even drier period in November 2019, L. Meyeri was identified. The results show that the presence of Leptospira was directly related to the water availability. This concludes that when a live-stock animal is infected it can pass through their urination which will be washed into the soil or water bodies with excessive rainfall or flooding. This occurrence will lead to the growth and spread of Leptospira which will have a negative effect on agriculture, economy, and environmental health. 

Article citation:

Chiani, Y. T., Jacob P., Mayora, G., Auino, D. S., Quintana, R. D., & Mesa, L. (2023). Presence of     Leptospira spp. in a mosaic of wetlands used for livestock raising under different hydroclimate         conditions. Applied and Environmental Microbiology, 89(6).https://doi.org/10.1128/aem.01971-22