Environmental and occupational risks for exposure to methicillin-resistant Staphylococcus

• Main Author: Peterson, Amy Eleanor
• Format: Dissertation
• Language: English
• Published: ProQuest Dissertations & Theses 01.01.2011
• Subjects: Antibiotics; Drug resistance; Environment; Epidemiology; Infections; Microbiology; Mortality; Occupational health; Pathogens; Public health; Staphylococcus infections
• ISBN: 9781124757919; 1124757910

Background. Antibiotic resistance is increasing in pathogenic and non-pathogenic bacterial populations both in healthcare settings and in the community. Resistant infections are a major component of emerging infectious diseases and multidrug resistance is increasing globally. Resistance to drugs carries a cost both in morbidity and in mortality. Methicillin-resistant Staphylococcus aureas (MRSA) is one of the most commonly recognized resistant pathogens and is a major public health concern in the US. Current nomenclature refers to MRSA as originating the community or in the hospital (CA-MRSA or HA-MRSA). Rates of infection and severity of disease have increased in the community, shifting focus from the healthcare setting as part of a rapidly shifting epidemic. Current surveillance methods for MRSA rely on screening for nasal colonization and focus on the hospital setting or on specific risk groups. However, MRSA has been seen in multiple animal species and transmission demonstrated from animals to humans and from humans to animals. As antibiotic use has increased in animals, resistant pathogens as well as drug residues are increasingly found in animal waste and in the environment surrounding farms as well as in food produced in this manner. Methods. This dissertation describes the role of agriculture in the development of antimicrobial resistant pathogens, the development and validation of a method for sampling MRSA from the environment, an investigation of occupational and environmental risk factors for community MRSA acquisition in patients entering a hospital, and the molecular profile of MRSA entering a hospital. Results. Farms appeared linked to the surrounding environment at the microbial level. Environmental sampling can be used to aid in better understanding this shifting epidemic. Designations for MRSA based on risk factors do not match those based on molecular diagnosis or antimicrobial profiles. Conclusions. Current designations of MRSA by suspected point of acquisition are increasingly arbitrary, and this nomenclature is no longer useful. In order to understand the increased resistance to antimicrobials in pathogens it is necessary to address the community component and to broaden the definition of community to include inputs from healthcare, agriculture, the environment, animals, and exposed workers to determine control or surveillance points.