Microbial Communities under Siege! Petroleum Hydrocarbons vs Microbial Community 

by: Diana Tarver

Figure 1. Species diversity and functional community and its relationship with soil multifunctionality in soils with different petroleum hydrocarbon contamination levels. The Simpson index (A) and Chao index (B) of the microbial community in highly contaminated soils (H), lightly contaminated soils (L) and uncontaminated soils (N). The Pearson correlation between the Simpson index (C) or Chao index (D) and soil multifunctionality in highly contaminated soils (H), lightly contaminated soils (L) and uncontaminated soils (N). The Pearson correlation between the Simpson index (E) or Chao index (F) and soil multifunctionality in all soil samples. The Wilcoxon rank-sum test was used to calculate significant differences (*p < 0.05; **p < 0.01; ***p < 0.001).

Environmental microbes are an important part of keeping the soils functioning and our tampering and adding of chemicals into the environment has made them evolve, and adapt to these chemicals.  Petroleum hydrocarbon, it changes the soil environment increasing organic carbon content changing how microbes interreact with soil. Some microbes have been able to adapt and to these contaminated soil. This study carried out by Wenjuan Jia and colleagues wanted to see how the diversity of these soil microbes were being affected by the petroleum hydrocarbon contamination. They went ahead and collected samples from 3 sites in Beijing China that had low, medium and high contamination. With these soil samples they did some culture dependent and independent studies on the microbes. Results concluded that there was a much lower diversity in high concentrations of petroleum hydrocarbons but surprisingly in the lower concentrations there was a huge increase in diversity giving us hope that these contaminated site will eventually heal. Although we may have known about the idea that microbes can help with contamination in the environment it is good to be able to see when we need to intervene this data could bring us closer in identifying what kind of management plan we can implement. 

Original Article 

Wenjuan J., Lirong C., Qiuyang T., Yueqiao L., Junfeng D., Kai Y., Qing Y., Senjie W., Jing L., Geng N., Lei Z., Aizhong D. (2023). Response of the soil microbial community to petroleum hydrocarbon stress shows a threshold effect: research on aged realistic contaminated fields. Frontiers in Microbiology Volume 14; 10.3389/fmicb.2023.1188229   

Environmental adaptation of host and a microbiome

By. Natalie Reyna

Results of common garden experiments, in which population growth was measured for C. elegans population isolated from mesocosms at day 100 ( final) and initial worm in present of mesocosms. Population growth is shown as offspring per worm added at the beginning of experiment. 

Microorganism when partnered up with plants and animals known to be microbiomes. Microbiomes are very important as they provide biological functions for various things such as digestion, nutrients and resistance to pathogens, and even help our immune system. With this in mind, its important to know how these microbes are able to acclimate and adapt to their changes in the environment they are associated with, typically microbes respond rapidly to these environments challenge both through genetic composition and phenotypically, however, host respond slower to a changing environment because they have longer generation time periods as compared to the microorganisms. 

Microbiome -medicated acclimate to environmental change has been documented before for multiple organisms. The model presented takes into consideration these factors disentangle the contributions of the host and microbiomes to metaorganisms adaption. Worms were harvested as well as associated microbiomes, to which were subjected to a common garden designed to unravel the impacts of microbiome composition and the host genetic adaptation. The results were that different forms of fitness occurred, being increasing and others decreased. The host and microbes play a factor in these adaptations paths.   

original article 

Petersen C, Hamerich IK, Adair KL, Griem-Krey H, Torres Oliva M, Hoeppner MP, Bohannan BJM, Schulenburg H. Host and microbiome jointly contribute to environmental adaptation. ISME J. 2023 Nov;17(11):1953-1965. doi: 10.1038/s41396-023-01507-9. Epub 2023 Sep 6. PMID: 37673969; PMCID: PMC10579302.

Overcoming contamination in hospital: Finding hidden source of bacteria in a radiopharmacy.

By: Albert Gonzalez

    Image of the locations sampled for bacterial content on surfaces in the hospital's radiopharmacy. Each red diamond shows the sampled location, and the arrows display the bacterial contamination's movement. 

Hospitals need to be as clean as possible; the patients' health rests on it. This being said, preventing bacterial contamination in a hospital environment is essential. A recent investigation surrounding sudden and persistent bacterial contamination of a hospital's radiopharmacy was conducted. Radiopharmacies are the section of the hospital that holds radioactive medicine. These medicines are highly important; protecting them from contamination is vital to their maintenance. In this investigation, the radiopharmacy unit of a university teaching hospital searched for the source of an ongoing bacterial contamination. They did this by testing the bacterial content of many surfaces. An interesting new method they used involved placing sterile water into a container, shaking it, and testing it to see what kinds of bacteria were on the surfaces of the container. The unit discovered that the contamination source came from reusable plastic containers. From the data gathered through this investigation, the unit realized the potential of old plastic containers to be a source of bacterial contamination and the effectiveness of a method for sampling surfaces for bacteria. These findings can be shared with other hospitals and help keep them free from contamination, ultimately ensuring patients' health.

Original article: Armando, M., Barthelemi, L., Couret, I., Verdier, C., Dupont, C., Jumas-Bilak, E., Grau, D., (2022) Recurrent environmental contamination in a centralized radiopharmacy unit by Achromobacter spp: Results of a large microbiological investigation. American Journal of Infection Control,  51, 5., 557-562.

Ions Effectively Inhibit Airborne Bacteria Viability

 By: Destinee Lopez

Figure 1 (A and B) S. aureus (A) and E. coli (B) plated at 104 CFU/ml on 150-mm petri dishes were subjected to a direct ion effect, with the ionizer positioned 5 or 10 cm away. n ≥ 3 duplicate studies. *, Student's t-tests; P < 0.05.

Human health depends on indoor air quality, and since airborne pathogens can be harmful, there is growing interest in air ionization technology as a potential means of reducing bacterial growth and improving overall air quality. This study investigates the impact of ion exposure on the survival of Staphylococcus aureus and Escherichia coli bacteria, regardless of whether the bacteria is trapped in air filters or plated on agar. Potential variations in the effects of exposure are examined, which may be influenced by factors such as filter type, action area, distance from the ion generator, bacterial type and load, and exposure time. This study supports the potential use of air ionizers for preventing and controlling indoor airborne infections by offering essential insights into the solid antibacterial activity of air ions and demonstrating their effectiveness in lowering the viability of common airborne pathogens, such as S. aureus and E. coli, under a variety of conditions. The purpose of the experiment was to determine how different experimental conditions, such as bacterial type and load, action area, distance from the ion generator, exposure time, and filter type, affected the viability of Staphylococcus aureus and Escherichia coli bacteria, both plated on agar and trapped in air filters. The results supported the potential use of air ionizers for preventing and controlling indoor airborne infections by showing a significant and consistent antibacterial activity of both positive and negative ions, which reduced the viability of both Staphylococcus aureus and Escherichia coli bacteria, whether plated on agar or trapped in air filters, across various experimental conditions. 

Original article: Comini, Mandras, N., Iannantuoni, M. R., Menotti, F., Musumeci, A. G., Piersigilli, G., Allizond, V., Banche, G., & Cuffini, A. M. (2021). Positive and Negative Ions Potently Inhibit the Viability of Airborne Gram-Positive and Gram-Negative Bacteria. Microbiology Spectrum, 9(3), e0065121–e0065121. https://doi.org/10.1128/Spectrum.00651-21

Dustborne vs Airborne Fungi in Domestic Environments

By: Esmeralda Sandoval

In recent years, poor aeration is a major cause of increasing microbial concentrations in domestic environments because of limited air exchange and removal of indoor pollutants due to windows not being left open in efforts to maintain comfortable climate conditions indoors. Dust serves as reservoir for fungi, allowing it to proliferate in high humidity conditions by using its organic matter. The dustborne fungi can then be suspended into the air and become airborne. In this study conducted by Pyrri and colleagues, fungal concentration were examined from the air and dust during the winter and summer months to determine the negative implications posed to human health. The results showed that fungal concentrations were higher in the summer, averaging at 931 CFU m-3 in the air, than in the winter, averaging at 739 CFU m-3. These concentrations are higher than the suggested level by the World Health Organization (WHO), 150 CFU m-3. These results indicate that when dust is not frequently removed, fungal concentrations increase allergen and pathogen exposure to humans.

Concentration of dustborne, expressed in CFU m−2, and airborne, expressed in CFU m−3 fungal exposure levels during the winter and summer. Figure taken from Pyrri et al. 2023.

Original Article:

Pyrri, I., Stamatelopoulou, A., Pardali, D., &amp; Maggos, T. (2023). The air and Dust Invisible mycobiome of urban domestic environments. Science of The Total Environment, 904, 166228. https://doi.org/10.1016/j.scitotenv.2023.166228 

Double Trouble Oil Degradation

 By: Raul Gonzalez

Bar graph representation of a 7-day culture biodegradation measurement of crude oil, saturates and aromatics by Bacillus subtilis and Pseudomonas aeruginosa.  T1 shows B. subtilis only, T2 is P aeruginosa, T3-T5 show both cultures at ratios of 1:1, 1:2, 2:1, respectively.  Figure taken from Wu et al. 2023.

Throughout history humans have caused negative impacts on environmental health, namely through crude oil spills like that of the Exon-Valdez disaster.  Several techniques have been used for oil clean-up with bioremediation being a helpful and cost-efficient method for large-scale disasters.  Bioremediation is a way to help clean up environmental pollutants by using biological organisms, like bacteria, to do the work.  A recent study conducted by Wu et al. in 2023 has taken bioremediation a step further by utilizing a co-culture method.  In this method, two bacterial species--Bacillus subtilis and Pseudomonas aeruginosa are grown in a petri dish containing crude oil to see how well they clean it up.  Other saturates (hydrocarbons) and aromatics were included in the study to see how well those were also cleaned up by the bacteria.  The methods included five observations: B. subtilis only, P. aeruginosa only, both bacteria at 1 to 1, 1 to 2, and 2 to 1 ratios, respectively.  The results showed that over the course of a 7-day period 63.05% of crude oil was degraded most efficiently by the 1 to 1 ratio of both bacteria working together.  This finding opens a new method for environmental scientists to approach bioremediation strategies that could provide a greater impact on pollutant clean-up efforts worldwide.  

Wu B, Xiu J, Yu L, Huang L, Yi L and Ma Y (2023) Degradation of crude oil in a co-culture system of Bacillus subtilis and Pseudomonas aeruginosa. Frontiers in Microbiology. 14:1132831.  https://doi.org/10.3389/fmicb.2023.1132831

Harmful algal blooms

 

Algal Blooms are a naturally occurring phenomena in freshwater and marine environments, blooms can be an essential part of an ecosystem, providing food and oxygen for the environment. However, human intervention has allowed algal blooms to become an environmental hazard. In the last 30 years, Factors such as climate change, agricultural runoff, and sewage pollution, have led to the harmful algal blooms to increase in frequency and intensity, leading to the formation of “Dead Zones”.  Dead Zones are named as such due to their low oxygen content and have caused species of fish to die off and negatively impacting the food web by causing the small organisms such as plankton to die off as well. The ability of certain species of algae to produce toxins can also negatively affect humans who are exposed to the infected bodies of water, not to mention the risk it poses to pets and livestock. Despite the fact the impact of blooms is detrimental to most environments they occur in, little is being done in the way of remedying the issue.