Faculty Opinions recommendation of The impact and mechanism of quaternary ammonium compounds on the transmission of antibiotic resistance genes.

The impact of amendment with swine manure compost (SMC), yard waste compost (YWC), or food waste compost (FWC) on the abundance of antibiotic resistance genes in soil was evaluated. Following a commercial-scale application of the composts in a field experiment, soils were sampled periodically for a decade, and archived air-dried. Soil DNA was extracted and gene targets quantified by qPCR. Compared with untreated control soil, all 3 amendment types increased the abundance of gene targets for up to 4 years postapplication. The abundance of several gene targets was much higher in soil amended with SMC than in soil receiving either YWC or FWC. The gene target ermB remained higher in the SMC treatment for a decade postapplication. Clostridia were significantly more abundant in the SMC-amended soil throughout the decade following application. Eight percent of Clostridium spp. isolates from the SMC treatment carried ermB. Overall, addition of organic amendments to soils has the potential to increase the abundance of antibiotic resistance genes. Amendments of fecal origin, such as SMC, will in addition entrain bacteria carrying antibiotic resistance genes. Environmentally recalcitrant clostridia, and the antibiotic resistance genes that they carry, will persist for many years under field conditions following the application of SMC.

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The Occurrence of Antibiotic Resistance Genes in an Urban River in Nepal

Water ◽

10.3390/w12020450 ◽

2020 ◽

Vol 12 (2) ◽

pp. 450 ◽

Cited By ~ 3

Author(s):

Ocean Thakali ◽

Sarmila Tandukar ◽

John Brooks ◽

Samendra Sherchan ◽

Jeevan Sherchand ◽

...

Keyword(s):

Antibiotic Resistance ◽

Resistance Genes ◽

Anthropogenic Activities ◽

Quantitative Polymerase Chain Reaction ◽

Antibiotic Resistance Genes ◽

Urban River ◽

Class 1 Integron ◽

Upstream Site ◽

Class 1 ◽

The Impact

Urban rivers affected by anthropogenic activities can act as reservoirs of antibiotic resistance genes (ARGs). This study aimed to describe the occurrence of selected ARGs (blaTEM, ermF, mecA, and tetA) and a class 1 integron (intI1) in an urban river in Nepal. A total of 18 water samples were collected periodically from upstream, midstream, and downstream sites along the Bagmati River over a 1-year period. All ARGs except mecA and intI1 were consistently detected by a quantitative polymerase chain reaction in the midstream and downstream sites, with concentrations ranging from 3.1 to 7.8 log copies/mL. ARG abundance was significantly lower at the upstream site (p < 0.05), reflecting the impact of anthropogenic activities on increasing concentrations of ARGs at midstream and downstream sites. Our findings demonstrate the presence of clinically relevant ARGs in the urban river water of Nepal, suggesting a need for mitigating strategies to prevent the spread of antibiotic resistance in the environment.

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The impact of on-site hospital wastewater treatment on the downstream communal wastewater system in terms of antibiotics and antibiotic resistance genes

International Journal of Hygiene and Environmental Health ◽

10.1016/j.ijheh.2019.01.004 ◽

2019 ◽

Vol 222 (4) ◽

pp. 635-644 ◽

Cited By ~ 27

Author(s):

Gabriela K. Paulus ◽

Luc M. Hornstra ◽

Nikiforos Alygizakis ◽

Jaroslav Slobodnik ◽

Nikolaos Thomaidis ◽

...

Keyword(s):

Antibiotic Resistance ◽

Wastewater Treatment ◽

Resistance Genes ◽

Antibiotic Resistance Genes ◽

Hospital Wastewater ◽

The Impact

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Distribution of antiseptic resistance genes in Staphylococcus spp. from bovine mastitis

Veterinární Medicína ◽

10.17221/265/2015-vetmed ◽

2017 ◽

Vol 62 (No. 4) ◽

pp. 200-203

Author(s):

Y. Ergun ◽

Z. Cantekin ◽

K. Gurturk ◽

H. Solmaz ◽

IH Ekin ◽

...

Keyword(s):

Public Health ◽

Resistance Genes ◽

Quaternary Ammonium ◽

Bovine Mastitis ◽

Quaternary Ammonium Compounds ◽

Staphylococcus Spp ◽

Ammonium Compounds

The purpose of this study was the determination of antiseptic resistance genes (qacA/B and qacC) from staphylococcal mastitis in cattle in various regions of Turkey. In total, 283 isolates (Burdur: 36, Hatay: 47 and Van: 200) were studied, and the antiseptic resistance genes were detected using simplex PCR. The distribution of the qacA/B and qacC genes, mediating resistance against quaternary ammonium compounds, was found to vary among the different isolates. The qacA/B genes were found in three of the Burdur isolates, six of the Hatay isolates and seven of the Van isolates. The qacC gene was found in two of the Burdur isolates, none of the Hatay isolates and two of the Van isolates. The presence of these genes and transmission among Staphylococcus spp. strains may pose risks in the control of mastitis, as well as to public health.

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Cohorting KPC+ Klebsiella pneumoniae (KPC-Kp)–positive patients: A genomic exposé of cross-colonization hazards in a long-term acute-care hospital (LTACH)

Infection Control and Hospital Epidemiology ◽

10.1017/ice.2020.261 ◽

2020 ◽

Vol 41 (10) ◽

pp. 1162-1168

Author(s):

Shawn E. Hawken ◽

Mary K. Hayden ◽

Karen Lolans ◽

Rachel D. Yelin ◽

Robert A. Weinstein ◽

...

Keyword(s):

Antibiotic Resistance ◽

Klebsiella Pneumoniae ◽

Acute Care ◽

Resistance Genes ◽

Acute Care Hospital ◽

Antibiotic Resistance Genes ◽

Care Hospital ◽

Cross Transmission ◽

The Impact

AbstractObjective:Cohorting patients who are colonized or infected with multidrug-resistant organisms (MDROs) protects uncolonized patients from acquiring MDROs in healthcare settings. The potential for cross transmission within the cohort and the possibility of colonized patients acquiring secondary isolates with additional antibiotic resistance traits is often neglected. We searched for evidence of cross transmission of KPC+ Klebsiella pneumoniae (KPC-Kp) colonization among cohorted patients in a long-term acute-care hospital (LTACH), and we evaluated the impact of secondary acquisitions on resistance potential.Design:Genomic epidemiological investigation.Setting:A high-prevalence LTACH during a bundled intervention that included cohorting KPC-Kp–positive patients.Methods:Whole-genome sequencing (WGS) and location data were analyzed to identify potential cases of cross transmission between cohorted patients.Results:Secondary KPC-Kp isolates from 19 of 28 admission-positive patients were more closely related to another patient’s isolate than to their own admission isolate. Of these 19 cases, 14 showed strong genomic evidence for cross transmission (<10 single nucleotide variants or SNVs), and most of these patients occupied shared cohort floors (12 patients) or rooms (4 patients) at the same time. Of the 14 patients with strong genomic evidence of acquisition, 12 acquired antibiotic resistance genes not found in their primary isolates.Conclusions:Acquisition of secondary KPC-Kp isolates carrying distinct antibiotic resistance genes was detected in nearly half of cohorted patients. These results highlight the importance of healthcare provider adherence to infection prevention protocols within cohort locations, and they indicate the need for future studies to assess whether multiple-strain acquisition increases risk of adverse patient outcomes.

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Analysis of Antibiotic Resistance Genes in Multidrug-Resistant Acinetobacter sp. Isolates from Military and Civilian Patients Treated at the Walter Reed Army Medical Center

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00778-06 ◽

2006 ◽

Vol 50 (12) ◽

pp. 4114-4123 ◽

Cited By ~ 270

Author(s):

Kristine M. Hujer ◽

Andrea M. Hujer ◽

Edward A. Hulten ◽

Saralee Bajaksouzian ◽

Jennifer M. Adams ◽

...

Keyword(s):

Antibiotic Resistance ◽

Resistance Genes ◽

Medical Center ◽

Antibiotic Resistance Genes ◽

Bloodstream Infections ◽

Multidrug Resistant ◽

Walter Reed Army Medical ◽

Army Medical ◽

Starting Point ◽

The Impact

ABSTRACT Military medical facilities treating patients injured in Iraq and Afghanistan have identified a large number of multidrug-resistant (MDR) Acinetobacter baumannii isolates. In order to anticipate the impact of these pathogens on patient care, we analyzed the antibiotic resistance genes responsible for the MDR phenotype in Acinetobacter sp. isolates collected from patients at the Walter Reed Army Medical Center (WRAMC). Susceptibility testing, PCR amplification of the genetic determinants of resistance, and clonality were determined. Seventy-five unique patient isolates were included in this study: 53% were from bloodstream infections, 89% were resistant to at least three classes of antibiotics, and 15% were resistant to all nine antibiotics tested. Thirty-seven percent of the isolates were recovered from patients nosocomially infected or colonized at the WRAMC. Sixteen unique resistance genes or gene families and four mobile genetic elements were detected. In addition, this is the first report of bla OXA-58-like and bla PER-like genes in the U.S. MDR A. baumannii isolates with at least eight identified resistance determinants were recovered from 49 of the 75 patients. Molecular typing revealed multiple clones, with eight major clonal types being nosocomially acquired and with more than 60% of the isolates being related to three pan-European types. This report gives a “snapshot” of the complex genetic background responsible for antimicrobial resistance in Acinetobacter spp. from the WRAMC. Identifying genes associated with the MDR phenotype and defining patterns of transmission serve as a starting point for devising strategies to limit the clinical impact of these serious infections.

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Estimating the conjugative transfer rate of antibiotic resistance genes: Effect of model structural errors

10.1101/2021.06.29.450325 ◽

2021 ◽

Author(s):

Sulagna Mishra ◽

Thomas U Berendonk ◽

David Kneis

Keyword(s):

Antibiotic Resistance ◽

Resistance Genes ◽

Rate Constants ◽

Transfer Rate ◽

Antibiotic Resistance Genes ◽

Plasmid Transfer ◽

Transfer Rates ◽

Model Predictions ◽

Mating Conditions ◽

The Impact

The spread of antibiotic resistance genes (ARG) occurs widely through plasmid transfer majorly facilitated via bacterial conjugation. To assess the spread of these mobile ARG, it is necessary to develop appropriate tools to estimate plasmid transfer rates under different environmental conditions. Process-based models are widely used for the estimation of plasmid transfer rate constants. Empirical studies have repeatedly highlighted the importance of subtle processes like delayed growth, the maturation of transconjugants, the physiological cost of plasmid carriage, and the dependence of conjugation on the culture′s growth stage. However, models used for estimating the transfer rates typically neglect them. We conducted virtual mating experiments to quantify the impact of these four typical structural model deficits on the estimated plasmid transfer rate constants. We found that under all conditions, the plasmid cost and the lag phase in growth must be taken into account to obtain unbiased estimates of plasmid transfer rate constants. We observed a tendency towards the underestimation of plasmid transfer rate constants when structurally deficient models were fitted to virtual mating data. This holds for all the structural deficits and mating conditions tested in our study. Our findings might explain an important component of the negative bias in model predictions known as the plasmid paradox. We also discuss other structural deficits that could lead to an overestimation of plasmid transfer rate constants and we demonstrate the impact of ill-fitted parameters on model predictions.

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Enterococcus faecalisCRISPR-Cas is a robust barrier to conjugative antibiotic resistance dissemination in the murine intestine

10.1101/312751 ◽

2018 ◽

Cited By ~ 2

Author(s):

Valerie J. Price ◽

Sara W. McBride ◽

Karthik Hullahalli ◽

Anushila Chatterjee ◽

Breck A. Duerkop ◽

...

Keyword(s):

Antibiotic Resistance ◽

Enterococcus Faecalis ◽

Resistance Genes ◽

Antibiotic Resistance Genes ◽

Conjugative Plasmids ◽

Resistance Plasmids ◽

The Impact ◽

Mammalian Intestine

AbstractCRISPR-Cas systems are barriers to horizontal gene transfer (HGT) in bacteria. Little is known about CRISPR-Cas interactions with conjugative plasmids, and studies investigating CRISPR-Cas/plasmid interactions inin vivomodels relevant to infectious disease are lacking. These are significant gaps in knowledge because conjugative plasmids disseminate antibiotic resistance genes among pathogensin vivo, and it is essential to identify strategies to reduce the spread of these elements. We use enterococci as models to understand the interactions of CRISPR-Cas with conjugative plasmids.Enterococcus faecalisis a native colonizer of the mammalian intestine and harbors pheromone-responsive plasmids (PRPs). PRPs mediate inter- and intraspecies transfer of antibiotic resistance genes. We assessedE. faecalisCRISPR-Cas anti-PRP activity in the mouse intestine and under varyingin vitroconditions. We observed striking differences in CRISPR-Cas efficiencyin vitroversusin vivo. With few exceptions, CRISPR-Cas blocked intestinal PRP dissemination, whilein vitro, the PRP frequently escaped CRISPR-Cas defense. Our results further the understanding of CRISPR-Cas biology by demonstrating that standardin vitroexperiments do not adequately model thein vivoanti-plasmid activity of CRISPR-Cas. Additionally, our work identifies several variables that impact the apparentin vitroanti-plasmid activity of CRISPR-Cas, including planktonic versus biofilm settings, different donor/recipient ratios, production of a plasmid-encoded bacteriocin, and the time point at which matings are sampled. Our results are clinically significant because they demonstrate that barriers to HGT encoded by normal human microbiota can have significant impacts onin vivoantibiotic resistance dissemination.ImportanceCRISPR-Cas is a type of immune system encoded by bacteria that is hypothesized to be a natural impediment to the spread of antibiotic resistance genes. In this study, we directly assessed the impact of CRISPR-Cas on antibiotic resistance dissemination in the mammalian intestine and under varyingin vitroconditions. We observed a robust effect of CRISPR-Cas onin vivobut notin vitrodissemination of antibiotic resistance plasmids in the native mammalian intestinal colonizerEnterococcus faecalis. We conclude that standard laboratory experiments currently do not appropriately model thein vivoconditions where antibiotic resistance dissemination occurs betweenE. faecalisstrains. Moreover, our results demonstrate that CRISPR-Cas encoded by native members of the mammalian intestinal microbiota can block the spread of antibiotic resistance plasmids.

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