Antibiotic resistant bacteria associated with biological aerosols within broiler houses

Authors: Brooks, John; Miles, Dana

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 2/15/2007
Publication Date: 5/21/2007
Citation: Brooks, J.P., Miles, D.M. 2007. Antibiotic resistant bacteria associated with biological aerosols within broiler houses [Abstract]. Proceedings American Society of Microbiology. CD-ROM.

Interpretive Summary:

Technical Abstract: Poultry are known to harbor antibiotic resistant and pathogenic bacteria, and as such poultry litter and poultry house air can be contaminated with these bacteria. Health researchers have typically focused on the presence of aerosolized endotoxin, NH3, and particulate matter within poultry houses; however, the presence of antibiotic resistant bacteria in biological aerosols is largely not understood. The purpose of this study was to determine the amount of aerosolized bacteria, particularly fecal indicators, staphylococci, and enterococci, associated with poultry house and outdoor air. Aerosol samples were collected using SKC Biosamplers in triplicate at multiple locations on the farm and in the house. Antibiotic resistance was investigated using the Kirby Bauer method on selected isolates using twelve different antibiotics spanning both narrow to broad spectrums of effectiveness. Overall, the presence of antibiotic resistant bacteria followed a cyclical trend, with 2 orders magnitude lower concentration during periods following litter removal in both the litter and aerosol samples. It was interesting to note that samples collected at the end of the house (near exhaust fans) produced counts approximately 1 order magnitude greater than samples collected in the center of the house. Typical isolates included Staphylococcus, Enterococcus, and Escherichia coli. It was estimated that Staphylococcus and Enterococcus bacteria accounted for at least 90% of cultured aerobic bacteria. Rarely was an isolate resistant to more than 4 antibiotics; however, members of the Pseudomonas genera were found to be resistant to more than 4 antibiotics. It appears that although levels of antibiotic resistant bacteria were highly concentrated within the house, levels were much lower outside of the house, and very little house escape was occuring. Simple use of hygienic masks and gloves would limit the amount of interaction between workers and any poultry litter associated bacteria, be it aerosol or litter contact.