Distribution of tetracycline resistance genes in anaerobic treatment of waste sludge: The role of pH in regulating tetracycline resistant bacteria and horizontal gene transfer

ABSTRACT Bacterial conjugation constitutes a major horizontal gene transfer mechanism for the dissemination of antibiotic resistance genes among human pathogens. Antibiotic resistance spread could be halted or diminished by molecules that interfere with the conjugation process. In this work, synthetic 2-alkynoic fatty acids were identified as a novel class of conjugation inhibitors. Their chemical properties were investigated by using the prototype 2-hexadecynoic acid and its derivatives. Essential features of effective inhibitors were the carboxylic group, an optimal long aliphatic chain of 16 carbon atoms, and one unsaturation. Chemical modification of these groups led to inactive or less-active derivatives. Conjugation inhibitors were found to act on the donor cell, affecting a wide number of pathogenic bacterial hosts, including Escherichia, Salmonella, Pseudomonas, and Acinetobacter spp. Conjugation inhibitors were active in inhibiting transfer of IncF, IncW, and IncH plasmids, moderately active against IncI, IncL/M, and IncX plasmids, and inactive against IncP and IncN plasmids. Importantly, the use of 2-hexadecynoic acid avoided the spread of a derepressed IncF plasmid into a recipient population, demonstrating the feasibility of abolishing the dissemination of antimicrobial resistances by blocking bacterial conjugation. IMPORTANCE Diseases caused by multidrug-resistant bacteria are taking an important toll with respect to human morbidity and mortality. The most relevant antibiotic resistance genes come to human pathogens carried by plasmids, mainly using conjugation as a transmission mechanism. Here, we identified and characterized a series of compounds that were active against several plasmid groups of clinical relevance, in a wide variety of bacterial hosts. These inhibitors might be used for fighting antibiotic-resistance dissemination by inhibiting conjugation. Potential inhibitors could be used in specific settings (e.g., farm, fish factory, or even clinical settings) to investigate their effect in the eradication of undesired resistances.

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Prevalence of sulfonamide-resistant bacteria, resistance genes and integron-associated horizontal gene transfer in natural water bodies and soils adjacent to a swine feedlot in northern Taiwan

Journal of Hazardous Materials ◽

10.1016/j.jhazmat.2014.02.016 ◽

2014 ◽

Vol 277 ◽

pp. 34-43 ◽

Cited By ~ 79

Author(s):

Jih-Tay Hsu ◽

Chia-Yang Chen ◽

Chu-Wen Young ◽

Wei-Liang Chao ◽

Mao-Hao Li ◽

...

Keyword(s):

Gene Transfer ◽

Horizontal Gene Transfer ◽

Resistance Genes ◽

Natural Water ◽

Water Bodies ◽

Resistant Bacteria ◽

Bacteria Resistance ◽

Natural Water Bodies ◽

Northern Taiwan

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Correlation among extracellular polymeric substances, tetracycline resistant bacteria and tetracycline resistance genes under trace tetracycline

Chemosphere ◽

10.1016/j.chemosphere.2014.09.078 ◽

2014 ◽

Vol 117 ◽

pp. 658-662 ◽

Cited By ~ 16

Author(s):

Man-hong Huang ◽

Wei Zhang ◽

Yu Zheng ◽

Wen Zhang

Keyword(s):

Resistance Genes ◽

Extracellular Polymeric Substances ◽

Tetracycline Resistance ◽

Resistant Bacteria ◽

Tetracycline Resistance Genes

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Potential Role of Veillonella spp. as a Reservoir of Transferable Tetracycline Resistance in the Oral Cavity

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00217-06 ◽

2006 ◽

Vol 50 (8) ◽

pp. 2866-2868 ◽

Cited By ~ 26

Author(s):

D. Ready ◽

J. Pratten ◽

A. P. Roberts ◽

R. Bedi ◽

P. Mullany ◽

...

Keyword(s):

Oral Cavity ◽

Resistance Gene ◽

Resistance Genes ◽

Potential Role ◽

Tetracycline Resistance ◽

Tetracycline Resistance Genes

ABSTRACT Twelve out of 96 Veillonella spp. isolated from oral samples harbored tetracycline resistance genes. The most common resistance gene was tet(M). A tet(M)-positive Veillonella dispar strain was shown to transfer a Tn916-like element to four Streptococcus spp. by conjugation at a frequency of 5.2 × 10−6 to 4.5 × 10−5 per recipient.

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Horizontal gene transfer facilitates the spread of extracellular antibiotic resistance genes in soil

10.1101/2021.12.05.471230 ◽

2021 ◽

Author(s):

Heather A. Kittredge ◽

Kevin M. Dougherty ◽

Sarah E. Evans

Keyword(s):

Antibiotic Resistance ◽

Gene Transfer ◽

Horizontal Gene Transfer ◽

Resistance Genes ◽

Natural Transformation ◽

Antibiotic Resistance Genes ◽

Live Cells ◽

Resistant Bacteria ◽

Antibiotic Resistant Bacteria ◽

Antibiotic Resistant

AbstractAntibiotic resistance genes (ARGs) are ubiquitous in the environment and pose a serious risk to human and veterinary health. While many studies focus on the spread of live antibiotic resistant bacteria throughout the environment, it is unclear whether extracellular ARGs from dead cells can transfer to live bacteria to facilitate the evolution of antibiotic resistance in nature. Here, we inoculate antibiotic-free soil with extracellular ARGs (eARGs) from dead Pseudeononas stutzeri cells and track the evolution of antibiotic resistance via natural transformation – a mechanism of horizontal gene transfer involving the genomic integration of eARGs. We find that transformation facilitates the rapid evolution of antibiotic resistance even when eARGs occur at low concentrations (0.25 μg g-1 soil). However, when eARGs are abundant, transformation increases substantially. The evolution of antibiotic resistance was high under soil moistures typical in terrestrial systems (5%-30% gravimetric water content) and was only inhibited at very high soil moistures (>30%). While eARGs transformed into live cells at a low frequency, exposure to a low dose of antibiotic allowed a small number of transformants to reach high abundances in laboratory populations, suggesting even rare transformation events pose a risk to human health. Overall, this work demonstrates that dead bacteria and their eARGs are an overlooked path to antibiotic resistance, and that disinfection alone is insufficient to stop the spread of antibiotic resistance. More generally, the spread of eARGs in antibiotic-free soil suggests that transformation allows genetic variants to establish at low frequencies in the absence of antibiotic selection.ImportanceOver the last decade, antibiotics in the environment have gained increasing attention because they can select for drug-resistant phenotypes that would have otherwise gone extinct. To counter this effect, bacterial populations exposed to antibiotics often undergo disinfection. However, the release of extracellular antibiotic resistance genes (eARGs) into the environment following disinfection can promote the transfer of eARGs through natural transformation. This phenomenon is well-documented in wastewater and drinking water, but yet to be investigated in soil. Our results directly demonstrate that eARGs from dead bacteria are an important, but often overlooked source of antibiotic resistance in soil. We conclude that disinfection alone is insufficient to prevent the spread of ARGs. Special caution should be taken in releasing antibiotics into the environment, even if there are no live antibiotic resistant bacteria in the community, as transformation allows DNA to maintain its biological activity past microbial death.

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The impact of a freshwater fish farm on the community of tetracycline-resistant bacteria and the structure of tetracycline resistance genes in river water

Chemosphere ◽

10.1016/j.chemosphere.2015.01.035 ◽

2015 ◽

Vol 128 ◽

pp. 134-141 ◽

Cited By ~ 65

Author(s):

Monika Harnisz ◽

Ewa Korzeniewska ◽

Iwona Gołaś

Keyword(s):

Freshwater Fish ◽

River Water ◽

Resistance Genes ◽

Tetracycline Resistance ◽

Fish Farm ◽

Resistant Bacteria ◽

Tetracycline Resistance Genes ◽

The Impact

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Prevalence of Tetracycline Resistance Genes in Oral Bacteria

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.47.3.878-882.2003 ◽

2003 ◽

Vol 47 (3) ◽

pp. 878-882 ◽

Cited By ~ 94

Author(s):

A. Villedieu ◽

M. L. Diaz-Torres ◽

N. Hunt ◽

R. McNab ◽

D. A. Spratt ◽

...

Keyword(s):

Resistance Genes ◽

Tetracycline Resistance ◽

Oral Bacteria ◽

Healthy Adults ◽

Resistant Bacteria ◽

First Report ◽

Tetracycline Resistance Genes ◽

Oral Microflora ◽

Genes Encoding ◽

Ribosomal Protection Protein

ABSTRACT Tetracycline is a broad-spectrum antibiotic used in humans, animals, and aquaculture; therefore, many bacteria from different ecosystems are exposed to this antibiotic. In order to determine the genetic basis for resistance to tetracycline in bacteria from the oral cavity, saliva and dental plaque samples were obtained from 20 healthy adults who had not taken antibiotics during the previous 3 months. The samples were screened for the presence of bacteria resistant to tetracycline, and the tetracycline resistance genes in these isolates were identified by multiplex PCR and DNA sequencing. Tetracycline-resistant bacteria constituted an average of 11% of the total cultivable oral microflora. A representative 105 tetracycline-resistant isolates from the 20 samples were investigated; most of the isolates carried tetracycline resistance genes encoding a ribosomal protection protein. The most common tet gene identified was tet(M), which was found in 79% of all the isolates. The second most common gene identified was tet(W), which was found in 21% of all the isolates, followed by tet(O) and tet(Q) (10.5 and 9.5% of the isolates, respectively) and then tet(S) (2.8% of the isolates). Tetracycline resistance genes encoding an efflux protein were detected in 4.8% of all the tetracycline-resistant isolates; 2.8% of the isolates had tet(L) and 1% carried tet(A) and tet(K) each. The results have shown that a variety of tetracycline resistance genes are present in the oral microflora of healthy adults. This is the first report of tet(W) in oral bacteria and the first report to show that tet(O), tet(Q), tet(A), and tet(S) can be found in some oral species.

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