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Chambers LE, Chang M, Boyina K, Williams A, Dye R, Miller RV, DeGear MA, Assefa S, Köhler GA, Champlin FR. Disparate outer membrane exclusionary properties underlie intrinsic resistance to hydrophobic substances in Pseudomonas spp. isolated from surface waters under triclosan selection. JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART A, TOXIC/HAZARDOUS SUBSTANCES & ENVIRONMENTAL ENGINEERING 2021; 56:257-268. [PMID: 33411598 DOI: 10.1080/10934529.2020.1868822] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2020] [Revised: 12/14/2020] [Accepted: 12/17/2020] [Indexed: 06/12/2023]
Abstract
Representative members of surface water microbiota were obtained from three unrelated municipal sites in Oklahoma by direct plating under selection by the hydrophobic biocide triclosan. Multiple methods were employed to determine if intrinsic triclosan resistance reflected resistance to hydrophobic molecules by virtue of outer membrane impermeability. While all but one organism isolated in the absence of triclosan were able to initiate growth on MacConkey agar, only one was able to initiate significant growth with triclosan present. In contrast, all bacteria selected with triclosan were identified as Pseudomonas spp. using 16S RNA gene sequencing and exhibited growth comparable to Pseudomonas aeruginosa controls in the presence of hydrophobic antibacterial agents to include triclosan. Two representative bacteria isolated in the absence of triclosan allowed for greater outer membrane association with the fluorescent hydrophobic probe 1-N-phenylnapthylamine than did two triclosan-resistant isolates. Compound 48/80 disruption of outer membrane impermeability properties for hydrophobic substances either partially or fully sensitized nine of twelve intrinsically resistant isolates to triclosan. These data suggest that outer membrane exclusion underlies intrinsic resistance to triclosan in some, but not all Pseudomonas spp. isolated by selection from municipal surface waters and implicates the involvement of concomitant triclosan resistance mechanisms.
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Affiliation(s)
- Lauren E Chambers
- Department of Biochemistry and Microbiology, Oklahoma State University Center for Health Sciences, Tulsa, Oklahoma, USA
| | - Mang Chang
- Department of Biochemistry and Microbiology, Oklahoma State University Center for Health Sciences, Tulsa, Oklahoma, USA
| | - Kavya Boyina
- Department of Biochemistry and Microbiology, Oklahoma State University Center for Health Sciences, Tulsa, Oklahoma, USA
| | - Ashton Williams
- Department of Biochemistry and Microbiology, Oklahoma State University Center for Health Sciences, Tulsa, Oklahoma, USA
| | - Rebecca Dye
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, Oklahoma, USA
| | - Robert V Miller
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, Oklahoma, USA
| | - Michelle A DeGear
- Department of Biochemistry and Microbiology, Oklahoma State University Center for Health Sciences, Tulsa, Oklahoma, USA
| | - Senait Assefa
- Department of Biochemistry and Microbiology, Oklahoma State University Center for Health Sciences, Tulsa, Oklahoma, USA
| | - Gerwald A Köhler
- Department of Biochemistry and Microbiology, Oklahoma State University Center for Health Sciences, Tulsa, Oklahoma, USA
| | - Franklin R Champlin
- Department of Biochemistry and Microbiology, Oklahoma State University Center for Health Sciences, Tulsa, Oklahoma, USA
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Salaheen S, Almario J, Biswas D. Inhibition of growth and alteration of host cell interactions of Pasteurella multocida with natural byproducts. Poult Sci 2014; 93:1375-82. [DOI: 10.3382/ps.2013-03828] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Ellison ML, Champlin FR. Outer membrane permeability for nonpolar antimicrobial agents underlies extreme susceptibility of Pasteurella multocida to the hydrophobic biocide triclosan. Vet Microbiol 2007; 124:310-8. [PMID: 17560745 DOI: 10.1016/j.vetmic.2007.04.038] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2007] [Revised: 04/09/2007] [Accepted: 04/25/2007] [Indexed: 10/23/2022]
Abstract
Pasteurella multocida exhibits nonspecific susceptibility to nonpolar antimicrobial agents such as triclosan, despite possessing an ultrastructurally typical gram-negative cell envelope. Capsulated and noncapsulated cell surface variants were examined to investigate the role outer membrane permeability plays in triclosan susceptibility. Test strains were unable to initiate growth in the presence of bile salts and were susceptible to triclosan with minimal inhibitory concentrations (MICs) ranging from 0.06 to 0.25 microg/ml. Disk agar diffusion bioassays revealed triclosan susceptibility to be dose dependent and all strains were susceptible to the hydrophobic antibiotics novobiocin, rifamycin SV, and chloramphenicol. Triclosan minimal bactericidal concentrations were greater than MICs, thereby suggesting that dose dependency reflected both bacteriostatic and bactericidal effects. Total and viable cell density growth kinetic determinations revealed a triclosan concentration of 2.0 microg/ml resulted in loss of batch culture viability within 4-24 h. Concentrations of 0.02 and 0.2 microg/ml exerted either a bacteriostatic or bactericidal effect depending on the strain. Uptake of the hydrophobic probe 1-N-phenylnaphthylamine was greater in P. multocida strains than refractory control organisms Pseudomonas aeruginosa and Escherichia coli thereby suggesting the presence of phospholipid bilayer regions in the outer membrane. Because triclosan inhibits a conserved enoyl-ACP reductase necessary for bacterial fatty acid biosynthesis, these data support the notion that extreme susceptibility in P. multocida is due to the general inability of the outer membrane to exclude nonpolar compounds. Moreover, susceptibility is independent of the presence of capsular material and the biocide is bactericidal in a concentration dependent manner.
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Affiliation(s)
- Matthew L Ellison
- Department of Biological Sciences, Mississippi State University, Mississippi State, MS 39762, USA.
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