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Bioaerosols are formed by suspension of biological origin in the air. Bioaerosols are particulate matter composed of live or dead bacteria and fungi, viruses, high molecular weight allergens, bacterial endotoxins, mycotoxins, pollen, plant fibers, etc. Exposure to bioaerosols may be associated with a wide range of adverse health effects including contagious infectious diseases, acute toxicity, allergies and cancer. Previous studies show that bioaerosols have an impact on homes of low economic status. Poor ventilation and hygiene, lack of proper maintenance and temperature regulation can impact bioaerosols in those areas leading to higher risks of respiratory and cardiovascular diseases. The objective of this study is to identify bacteria present in aerosols using a Two-Stage Viable Anderson Cascade impactor for collection, both inside and outside low-income houses located in the Chamizal, Westside and Northeast areas of El Paso, Texas. This project focuses on the second stage of the cascade impactor, which collects fine size particles (1 – 8
m) that can reach human lungs. A total of 15 houses were sampled. Sampling for indoor and outdoor bioaerosols were conducted for a period of 15 minutes at 28.3 L/min using the cascade impactor loaded with 100 × 15-mm plastic Petri dishes with 20 mL of TSA containing 5% sheep blood.
Isolates were analyzed using a Micro Scan Auto Scan 4 automated bacterial identification system. Six
-
isolates showed a probability of correct identification (PCI) ranging from 97.34 to 99.77%. Four
isolates with a
PCI ranging from 89.49 to 99.26%. Four
.
isolates showed a PCI ranging from 85.42 to 99.71%.Three
with a PCI ranging from 99.29 to
99.99%.Two
isolates with a PCI ranging from 45.51 to 86.37%. One isolate each of
and
with a PCIs of 99.99%. Preliminary results show that potentially pathogenic bacteria were present inside low-income homes in this area.
Bioaerosols consist of inorganic and organic matter including bacteria, fungi, pollen, endotxins, viruses, etc [1]. The size of these bioaerosols range from 0.001 to 100
m [2]. Particles area size of 0.02 to 8.0
m can make their way down the respiratory and pulmonary tract [3]. Inhalation of these particles can lead to different health effects such as asthma, bronchitis, and emphysema
[4]. Some pathogenic bioaerosols can lead to more severe health effects especially on those who are immunocompromised [5]. Some of the sources of these pathogens come from humans, animal houses, and water treatment plants [6]. High winds can suspend these pathogens into the air and travel many miles (depending on their size) [7]. Some of the factors that affect the presence of indoor bioaerosols are temperature, humidity, pets, and ventilation systems. A study in Boston suggests that people who live in low-income areas tend to have higher amounts of exposure to bioaerosols because of the indoor and outdoor environments they reside in [8]. El Paso, TX, is an interesting city due to it’s surrounding environments. El Paso is surrounded by mountains (Northeast), dairy farms (Westside), and is a border city to
, Mexico. Few studies for bioaerosols have been conducted in El Paso area but those few studies have shown presence of multi-drug resistant
in indoor houses
[9]. The lack of studies about El Paso, TX low income environments, the need to conduct such studies to try to find a correlation between health effects and external environments is of paramount importance.
The primary objective is to capture fine size particle bioaerosols in the low income areas of Northeast, Westside, and South of El Paso, TX, for identification and characterization.
Geographic location is a determinant factor for the presence of pathogenic bacteria.
Three different sites of El Paso, TX, were sampled for the fine size bioaerosols. A two stage cascade impactor was used to capture the particles. This study focuses on the second stage of the impactor, which captures particles whose size range from .08 to 8.0 µm. The cascade impactor was loaded with Tryptic Soy Agar plates containing 5% sheep blood and ran for 15 minutes both indoors and outdoors concurrently. After collection, the samples were taken back to the lab and incubated for 24 hours at 35 o C. After incubation, the samples were analyzed and streaked for isolation onto TSA plates. The gram stain method was thus applied to verify cellular morphology. After identifying most of to the bacteria as gram positive, the isolates were ran through the Micro Scan Auto 4 Automated. This machine uses a series of chemical test to identify the carbon source of the bacteria and the antibiotic susceptibility.
Bacteria
Identified :
Indoors
Number of
Isolates:
1
1
1
1
Probability of
Correct
Identification:
99.99%
Bacteria
Identified :
Outdoors
89.49%
99.69%
93.92%
Number of
Isolates:
1
1
1
1
1 99.99%
an isolate of
and
were below the standard range of 85%.
Bacteria
Identified :
Indoors
Number of
Isolates:
2
1
1
1
3
Bacteria
Indoors
Number of
1
.
7
1
1
1
Probability of
Correct
Identification:
82.49-99.26%
99.77%
85.91%
99.59%
98.83-99.77%
Probability of
Correct
Identification:
99.99%
98.78%
99.57%
99.26%
Bacteria
Identified :
Outdoors
Number of
Isolates:
2
1
1
1
1
Probability of
Correct
Identification:
97.34-99.09%
99.71%
86.37%
98.78%
98.34%
Probability of
Identification:
98.54%
Bacteria Number of Probability of
Indoors Identification:
Outdoor samples demonstrated no growth or low probability of correct identification: Below
85%.
95-99.99%
87.98-98.76%
99.99%
98.83%
Preliminary results show that potentially pathogenic bacteria were present in lowincome homes in this area. The presence of
is very important especially in indoor environments. Exposure to this bacteria could cause skin and soft tissue infections as well as infect the bloodstream, cause pneumonia and joint infections, and septicemia . People who have chronic conditions tend to be at higher risks to develop complications as well as young children. The presence of this pathogen in low income communities is also alarming due to the fact that low income communities tend to have higher risk for chronic conditions. It is important to study this bacteria more and see if it is methillicin resistant as it can pose further complications.
The presence of the pathogen
exists in human skin but may be able to cause opportunistic infections or septis.
nd
are harmless to those who are healthy but can become virulent in individuals whose immune system are compromised. Detection of pathogenic bacteria is important especially in low income communities as they tend to be at higher risk for health problems. Continuing to characterize and identify harmful pathogens is important for future interventions in these communities.
Future studies consist of continue sampling year round in all three sites: Northeast,
Westside, and South of El Paso, TX. PCR method will be used to quantify and verify bacterial identification. Also, collection of gram negative bacteria will be done using
MacConkey agar to identify and characterize other potential pathogens.
• [1],[2],[3],[7]: Mandal, J., & Brandl H. (2011). Bioaersols in Indoor
Environment- A Review with Special Reference to Residential and
Occupational Locations.
4, 83-96. Retrieved from
• [4],[5],[6]: University of Florida. Aerosol Science & Engineering. Washington
University. Retrieved from
• [8]: Adamkiewicz G, Spengler JD, Harley AE, Stoddard A, Yang A, Alvarez-
Reeves M, Sorensen G. Environmental Conditions within Low-income Urban
Housing: Clustering and Associations with Self-reported Health.
. Published online ahead of print September 12, 2013: e1–e7. doi:10.2105/AJPH.2013.301253.
• [9]: Gandara, A., Mota, L. C., Flores, C., Perez, H. R., Green, C. F., & Gibbs, S.
G. (2006). Isolation of Staphylococcus aureus and antibiotic-resistant
Staphylococcus aureus from residential indoor bioaerosols.
, 114, 1859-1864.
Raul Higuera and the research reported in this publication was supported in part by the
National Institute of General Medical Sciences of the National Institutes of Health under Award Number R25GM060424. This research was also funded in part by the
NIH/NIEH grant number 1RO1ES022248-01. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National
Institutes of Health.