The
transfer and transport of antibiotic resistance in metal-contaminated
streams
One
aspect challenging public health efforts to minimize the spread of antibiotic
resistance (AR) is the prevalence of resistant bacteria in the environment.
Anthropogenic-derived agents of selection are typically implicated as
mechanisms for maintaining AR in the environment, whether it is through
the release of antibiotics or resistant bacteria from confined animal
feeding operations, hospital waste, or sewage treatment facilities.
An increasing number of studies have documented an additional mechanism
for maintaining AR in the environment through bacterial co-resistance
or cross-resistance to metals. Studies conducted at the Savannah River
Ecology Laboratory demonstrate that bacteria collected from metal-contaminated
streams have a higher frequency of antibiotic and metal resistance compared
to reference streams despite no significant source of anthropogenic-derived
antibiotics or sewage inputs at these sites. Therefore, it is likely
that metal contamination directly selects for metal-tolerant bacteria
while co-selecting for antibiotic resistant bacteria. The objective
of my research is to investigate what mechanisms are involved in the
development and transmission of antibiotic resistance in systems with
metal contamination.
Research
Interests
My research interests encompass a broad range of microbial ecology and
evolutionary questions. My dissertation research focuses on examining
the effects of varying degrees of selective pressures on microbial evolution
at the molecular and ecosystem scale. In addition to assessing potential
mechanisms involved in the co-selection of antibiotic and metal resistance,
I am investigating the role of class I integrons in the evolution of
environmental bacteria in the presence or absence of a selective agent
(i.e., cadmium). The approach I use quantifies the abundance of IntI1
genes through quantitative PCR and assesses the structure and function
of integron-associated gene cassettes. For this I am also characterizing
individual isolates and microbial communities from contaminated and
reference sites with both phenotypic (antibiotic and metal resistance
profiles) and genotypic assays (gene cassette sequencing for a functional
assessment and cassette diversity analysis for a structural assessment).
With regards to microbial ecology, I am particularly interested in the
feedbacks between microbial community structure at both the species
and gene levels of organization and ecosystem properties.
Publications
Wright, M.S., G. Loeffler Peltier, R. Stepanuaskas, JV. McArthur. In
press. Bacterial tolerances to metals and antibiotics in metal-contaminated
and reference streams. FEMS Microbiology Ecology.
Baker-Austin, C*., M.S. Wright*, R. Stepanauskas, JV. McArthur. 2006. Co-selection for antibiotic and metal resistance. Trends in Microbiology 14:176-182. *Authors contributed equally to this work.
Wright, M.S. and A.P. Covich. 2005. Relative importance of bacteria and fungi in a tropical headwater stream: Leaf decomposition and invertebrate feeding preference. Microbial Ecology 49(4):536-546 .
Wright,
M.S. and A.P. Covich. 2005. The effect of macroinvertebrate exclusion
on leaf breakdown rates in a tropical headwater stream. Biotropica 37(3):403-408.
Curriculum Vitae
| Savannah
River Ecology Laboratory Drawer E Aiken, SC, 29802 phone (office): (803) 952-7425 fax (SREL): (803) 952-7413 email: mswrightatuga.edu |
Institute
of Ecology University of Georgia Athens, GA 30602 phone (office): (706) 542-2968 fax (UGA): (706) 542-4819 http://arches.uga.edu/~mswright |
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