Public Health Commons^™

Oral Localization Of Scardovia Wiggsiae, Graydon Ramos Carr

UNLV Theses, Dissertations, Professional Papers, and Capstones

Early childhood caries is one of the most prevalent diseases in the United States among children. The formation of caries is a complex, multifactorial process that is still being studied. Researchers have thought for years that Streptococcus mutans was the primary causative agent of early childhood caries. The recent discovery of a novel cariogenic pathogen, Scardovia wiggsiae and its significant contribution to the etiology of early childhood caries has led oral health researchers to re-evaluate this microorganism and its link to this disease. While there have been several projects undertaken within the University of Nevada, Las Vegas School of Dental …

Evaluation Of A Fluorescence Method For Quantifying Bioaerosol Concentrations On Air Quality Filter Samples, Rachel Kolberg

UNLV Theses, Dissertations, Professional Papers, and Capstones

Airborne particulate matter (PM) in outdoor environments contains many components that cause adverse human health effects. The size of the particulates determine in what manner the particles would bypass the body’s defense mechanisms to enter the respiratory system and is directly related to their health impacts. Currently the United States Environmental Protection Agency is enforcing the National Ambient Air Quality Standards (NAAQS) to regulate the annual and 24-hour average concentrations of PM2.5 and PM10 in the air. PM2.5 are fine particles with aerodynamic diameter <2.5μm, small enough to reach the deepest parts of the bronchi and lungs. PM10 include PM2.5 and larger particles with aerodynamic diameter of 2.5-10μm. Both PM2.5 and PM10 contain multiple components from multiple sources. Bioaerosols are an important component of PM, but there is limited knowledge about how bioaerosols contribute to PM2.5 and PM10 concentrations. There is also a lack of research about the incidence and prevalence of disease caused by bioaerosols and about the limits of exposure to bioaerosol particulates. The main barrier to assess bioaerosol concentrations and health-related effects is the absence of quick and inexpensive methodology for quantifying bioaerosols. This study explored the feasibility of using fluorescence microscopy to quickly quantify bioaerosols in PM2.5 and PM10 collected on polycarbonate filters. Bioaerosols were stained with a DNA marker directly on a filter, followed by fixation, microscopic imaging, and automatic counting. The method was first validated using reference samples prepared by depositing different known concentrations of E. coli onto blank polycarbonate filters. The results indicated a linear response over two orders of magnitude (R2 = 0.9) and an accuracy within ±25%. E. coli were also deposited onto selected ambient PM10 and PM2.5 filter samples to determine if pre-loaded particles would interfere with bioaerosol imaging and counting. It was found that despite an increase in uncertainty (variability), the calibration slope remained within ±10% of unity for both PM2.5 and PM10 samples. Bioaerosol concentrations in ambient samples, as quantified by this method, were on average 14% higher for PM10 than for PM2.5 acquired concurrently in a desert environment of Las Vegas, Nevada. The application of this method to other types of compliance filters, such as Teflon filters and tapes of a Beta Attenuation Monitor (BAM) were also explored in this study. By means of a high-yield approach this method is expected to facilitate bioaerosol research, support exposure and health assessments, and help refine NAAQS for PM2.5 and PM10.

Microbial Contamination Of Ice At Food Establishments In Las Vegas, Nevada, Jerry Wills

UNLV Theses, Dissertations, Professional Papers, and Capstones

When food establishments make ice for consumption, it is important to use water free of pathogens and to employ hygienic practices. Freezing can reduce the number of culturable microorganisms present in water but does not eliminate them completely. Coliform bacteria are used as an indicator of water quality and are used to test for fecal contamination. The U.S. Environmental Protection Agency (EPA) establishes standards for drinking water, and has set a goal for zero total coliforms. Another commonly used tool to measure water quality is the heterotrophic plate count (HPC). The EPA limit for HPC is 500 colony forming units …

Effectiveness Of Commercially-Available Cosmetic Cleaners On Cosmetics And Cosmetic Brushes, Vanessa Ortiz

UNLV Theses, Dissertations, Professional Papers, and Capstones

The complex nature of skin contributes to the microbial population present on its surface. While normal skin flora is either beneficial or has no effect on the body, there are instances where pathogenic microorganisms are present and can cause infections. Damaged skin is more susceptible to infections from these microbes. Behavioral characteristics, such as the use of cosmetics, can affect the microbial population present on the skin. Staphylococcus aureus is the organism most commonly isolated from cosmetics, and it can be responsible for conjunctivitis, impetigo, boils, and folliculitis.

There are many ways microbial contamination of cosmetics can occur, such as …

Determining The Presence Of Carbapenem Antibiotic Resistance In Clinical Isolates, Fidelis Uzoma Enyinnaya

UNLV Theses, Dissertations, Professional Papers, and Capstones

Carbapenems are β-lactam antibiotics reserved for the treatment of severe microbial infections, especially those targeting the Enterobacteriaceae. Introduced in the 1980s, carbapenems have been used successfully in hospitals, and in the 1990s resistance was discovered. Carbapenem resistance is conferred through the production of carbapenemases. In the U.S., the most common carbapenemase is Klebsiella pneumoniae carbapenemase (KPC). In 2012, the National Healthcare Safety Network reported a carbapenem resistance rate of 13.0% among Klebsiella pneumoniae infections, and indicated that the mortality rate associated with carbapenem resistant Enterobacteriaceae (CRE) infections ranged from 48.0-71.9%. According to the Food and Drug Administration (FDA), carbapenem resistance …

Development Of A Molecular Method For Detecting The Causative Agent Of Swimmer's Itch (Trichobilharzia) In Freshwater Ecosystems, Heidi Mcmaster

UNLV Theses, Dissertations, Professional Papers, and Capstones

Cercarial dermatitis, commonly known as swimmer's itch, is caused by penetration of larvae of the schistosome,Trichobilharzia, into the dermis and epidermis layers of the skin. Symptoms are characterized by painful swelling and itching at the site of penetration. The normal hosts for the life cycle of the schistosome are aquatic birds and aquatic snails. The most frequently used method of detection forTrichobilharziais microscopy. With increases in the occurrence of cercarial dermatitis outbreaks in freshwater in the Southwestern United States, it is becoming increasingly important to develop and standardize a molecular method for rapid detection that can assist health professionals and …

The Presence Of Methicillin Resistant Staphylococcus Aureus (Mrsa) On Environmental Surfaces In Healthcare Facilities Pre- And Post-Cleaning, Aaron Thomas Hunt

UNLV Theses, Dissertations, Professional Papers, and Capstones

The emergence of antibiotic resistant bacteria is a serious public health issue affecting millions of people. Methicillin-resistant Staphylococcus aureus(MRSA) is a leading cause of healthcare acquired infections today. Research has shown that patients infected or colonized with MRSA shed the bacteria into the environment, where the bacteria can survive for long periods of time and become potential sources of infection. Currently, infection prevention efforts focus on active surveillance, hand hygiene, personal protective equipment use and antimicrobial stewardship, with less attention given to environmental cleaning. Nevertheless, environmental cleaning is essential to remove infectious agents from environmental surfaces and prevent transmission. The …

Vertical Transmission Of West Nile Virus In Culex Spp. Mosquitoes Of Clark County, Nevada, Vivek K. Raman

UNLV Theses, Dissertations, Professional Papers, and Capstones

West Nile Virus (WNV) is an RNA arbovirus that cycles between mosquitoes and birds, but also infects and causes disease in humans, horses and other vertebrate species. Although most infections are asymptomatic, WNV has emerged as the most common cause of epidemic meningoencephalitis in North America and the leading cause of arboviral encephalitis in the United States.

Mosquitoes of the genus Culex are the most active vectors of WNV in North America. Approximately 85% of human WNV infections in the United States occur in late summer with a peak number of cases in August and September. Vertical transmission is defined …

An Evaluation Of Methicillin Resistant Staphylococcus Aureus Survival On Five Environmental Surfaces Under Two Different Humidities, With And Without The Addition Of Bovine Serum Albumin, Courtney Ann Coughenour

UNLV Theses, Dissertations, Professional Papers, and Capstones

The spread of antibiotic resistant bacteria is a major public health concern, as they result in greater healthcare costs and increased morbidity and mortality rates. Methicillin resistant Staphylococcus aureus (MRSA) is one organism of particular concern, with the number of infections increasing in epidemic proportion. Bacterial surface contamination with MRSA is significant, as it may serve as a reservoir for transmission and have negative health implications. The purpose of this study was to evaluate survival of MRSA on five environmental surface materials; glass, wood, vinyl, plastic, and cloth. The effect of relative humidity (RH) and bovine serum albumin (BSA) were …

Molecular Epidemiology Of Methicillin-Resistant Staphylococcus Aureus (Mrsa), Ilene Bautista

UNLV Theses, Dissertations, Professional Papers, and Capstones

Staphylococcus aureus is a frequent cause of a myriad of infections in hospitals, healthcare facilities and community settings. It is often related to skin and soft tissue infection, but it can also cause other diseases varying from food poisoning to endocarditis and toxic shock syndrome. According to a study by Kuehnert et al. (2006) there has been a strong association between Staphylococcus aureus (S. aureus) carriage and risk factors for subsequent infections. Subsequent infection from S. aureus , including methicillin-resistant S. aureus (MRSA) infection, can be projected by looking at the presence of S. aureus nasal colonization. The purpose of …