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139 results on '"Mollenkopf, Dixie F."'

1. Carbapenemase-producing bacteria recovered from Nairobi River, Kenya surface water and from nearby anthropogenic and zoonotic sources.

Author

Too, Rael J., Kariuki, Samuel M., Gitao, George C., Bebora, Lilly C., Mollenkopf, Dixie F., and Wittum, Thomas E.

Abstract

Carbapenem-resistant bacteria (CRB) present a significant global public health concern. Sub-Saharan Africa has borne a heavy burden of CRB with a reported prevalence of up to 60% in some patient populations. es in Africa focus on clinical CRB isolates, with limited data on their spread in the natural environment. Therefore, the purpose of this study was to report the recovery of CRB from Nairobi River surface waters and nearby anthropogenic and zoonotic sources in Nairobi County, Kenya. A total of 336 CRB were recovered from 336 (250 mL) samples, with 230 of the samples (68.5%) producing one or more CRB isolates. CRB were recovered most commonly from untreated sewage influent (100% of 36 samples; 79 total isolates), treated effluent (93% of 118 samples; 116 total isolates), Nairobi River surface waters upstream (100% of 36 samples; 57 total isolates), downstream (100% of 36 samples; 45 total isolates), and way downstream from the wastewater treatment plant (73% of 11 samples; 19 total isolates), slaughterhouse effluent discharges 1.5%, (5/336), animal contact areas 0.9%, (3/336), a manhole sewer from the affluent neighborhood of Karen at 2.7%, (9/336) respectively. The CRB included Escherichia coli (158, 47%), Klebsiella pneumoniae (74, 22%), and Enterobacter spp (43, 13%). Aeromonas spp (29, 9%) Acinetobacter baumannii (12, 3.6%), Citrobacter freundii (7, 2.1%), Pseudomonas aeruginosa (5, 1.5%) and other species (8, 2.4%). CRB genotypes included blaNDM (246, 73.2%), blaKPC (40, 12%), blaVIM (51, 15.2%), blaOXA-48-like (65, 19.3%), blaIMP (15, 4.5%), and blaGES (7, 2.1%). Sixty-nine of the CRB isolates (20.5%) harbored multiple carbapenemase-encoding genes. Our results indicate that clinically important CRB are commonly present in Nairobi River surface water and from nearby wastewater and livestock sources. These pose an important public health threat that requires urgent intervention strategies and additional investigation. [ABSTRACT FROM AUTHOR]

Published
2024
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9. Prevalence Estimation, Antimicrobial Susceptibility, and Serotyping of Salmonella enterica Recovered from New World Non-Human Primates (Platyrrhini), Feed, and Environmental Surfaces from Wildlife Centers in Costa Rica

Author

Rojas-Sánchez, Ernesto, primary, Jiménez-Soto, Mauricio, additional, Barquero-Calvo, Elias, additional, Duarte-Martínez, Francisco, additional, Mollenkopf, Dixie F., additional, Wittum, Thomas E., additional, and Muñoz-Vargas, Lohendy, additional

Published
2023
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17. Prevalence of extended-spectrum cephalosporin-, carbapenem-, and fluoroquinolone-resistant members of the family Enterobacteriaceae isolated from the feces of horses and hospital surfaces at two equine specialty hospitals

Author

Adams, Rachael J., primary, Mollenkopf, Dixie F., additional, Mathys, Dimitria A., additional, Whittle, Andrea, additional, Ballash, Greg A., additional, Mudge, Margaret, additional, Daniels, Joshua B., additional, Barr, Bonnie, additional, and Wittum, Thomas E., additional

Published
2021
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19. Implementation of an antimicrobial stewardship program in a veterinary medical teaching institution

Author

Feyes, Emily E., primary, Diaz-Campos, Dubraska, additional, Mollenkopf, Dixie F., additional, Horne, Rikki L., additional, Soltys, Rachel C., additional, Ballash, Greg A., additional, Shelby, Jessica A., additional, Reed, Erica E., additional, Stevenson, Kurt B., additional, Daniels, Joshua B., additional, Stull, Jason W., additional, and Wittum, Thomas E., additional

Published
2021
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23. Carbapenemase-producing Enterobacteriaceae and Aeromonas spp. present in wastewater treatment plant effluent and nearby surface waters in the US

Author

Mathys, Dimitria A., primary, Mollenkopf, Dixie F., additional, Feicht, Sydnee M., additional, Adams, Rachael J., additional, Albers, Amy L., additional, Stuever, David M., additional, Grooters, Susan V., additional, Ballash, Gregory A., additional, Daniels, Joshua B., additional, and Wittum, Thomas E., additional

Published
2019
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35. A complex cyclical One Health pathway drives the emergence and dissemination of antimicrobial resistance.

Author

Parker, Elizabeth M., Ballash, Gregory A., Mollenkopf, Dixie F., and Wittum, Thomas E.

Subjects
*DRUG resistance in microorganisms, *DRUG resistance in bacteria, *BACTERIAL genes, *BACTERIAL population, *WASTEWATER treatment, *WASTE products
Abstract

Since their commercialization, scientists have known that antimicrobial use kills or inhibits susceptible bacteria while allowing resistant bacteria to survive and expand. Today there is widespread antimicrobial resistance (AMR), even to antimicrobials of last resort such as the carbapenems, which are reserved for use in life-threatening infections. It is often convenient to assign responsibility for this global health crisis to the users and prescribers of antimicrobials. However, we know that animals never treated with antimicrobials carry clinically relevant AMR bacteria and genes. The causal pathway from bacterial susceptibility to resistance is not simple, and dissemination is cyclical rather than linear. Amplification of AMR occurs in healthcare environments and on farms where frequent exposure to antimicrobials selects for resistant bacterial populations. The recipients of antimicrobial therapy release antimicrobial residues, resistant bacteria, and resistance genes in waste products. These are reduced but not removed during wastewater and manure treatment and enter surface waters, soils, recreational parks, wildlife, and fields where animals graze and crops are grown for human and animal consumption. The cycle is complete when a patient carrying AMR bacteria is treated with antimicrobials that amplify the resistant bacterial populations. Reducing the development and spread of AMR requires a One Health approach with the combined commitment of governments, medical and veterinary professionals, agricultural industries, food and feed processors, and environmental scientists. In this review and in the companion Currents in One Health by Ballash et al, JAVMA, April 2024, we highlight just a few of the steps of the complex cyclical causal pathway that leads to the amplification, dissemination, and maintenance of AMR. [ABSTRACT FROM AUTHOR]

Published
2024
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40. Carbapenemase-Producing Aeromonas veronii Disseminated in the Environment of an Equine Specialty Hospital.

Author

Adams, Rachael J., Mathys, Dimitria A., Mollenkopf, Dixie F., Whittle, Andrea, Daniels, Joshua B., and Wittum, Thomas E.

Subjects
DRUG resistance in bacteria, CARBAPENEMASE, PUBLIC health
Abstract

The emergence of bacterial resistance to carbapenem antibiotics is an urgent public health threat. Carbapenem drugs are a last resort treatment option for life-threatening infections. The frequent use of broad-spectrum antibiotics to treat hospitalized patients provides significant selection pressure favoring the emergence and dissemination of resistant organisms, including carbapenem-resistant Enterobacteriaceae (CRE). CREs have been reported in animal populations, but only rarely in horses. Our objective was to determine the prevalence of CRE in the environment of a referral equine specialty hospital. Environmental samples were collected on seven different sampling dates. Four clonal carbapenemase-producing Aeromonas veronii were recovered from 315 sampled surfaces (1.3%). All four isolates harbored the carbapenemase-producing, metallo-β-lactamase gene blacphA, although corresponding minimum inhibitory concentrations were within the susceptible range for imipenem and meropenem. All had an identical multilocus sequence type with a previously unreported allelic profile and contained multiple plasmids. To our knowledge, this recovery of blacphA-harboring A. veronii is the first report of carbapenemase-producing bacteria in the environment of an equine veterinary hospital. However, the low recovery rate suggests that environmental contamination is uncommon. Appropriate hospital cleaning and disinfection protocols are necessary to maintain a low risk of contamination for patients and personnel. [ABSTRACT FROM AUTHOR]

Published
2017
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41. Enterobacteriaceae Harboring AmpC ( blaCMY) and ESBL ( blaCTX-M) in Migratory and Nonmigratory Wild Songbird Populations on Ohio Dairies.

Author

Mathys, Dimitria A., Mathys, Blake A., Mollenkopf, Dixie F., Daniels, Joshua B., and Wittum, Thomas E.

Subjects
ENTEROBACTERIACEAE, DRUG resistance in bacteria, SONGBIRDS, FOODBORNE diseases, EPIDEMIOLOGY, DISEASE prevalence
Abstract

Extended-spectrum β-lactamases (ESBLs) confer bacterial resistance to critically important antimicrobials, including extended-spectrum cephalosporins (ESCs). Livestock are important reservoirs for the zoonotic food-borne transmission of ESC-resistant enteric bacteria. Our aim is to describe the potential role of migratory and resident wild birds in the epidemiology of ESBL-mediated bacterial resistance on dairy farms. Using mist nets, we sampled wild migratory and resident birds either immediately adjacent to or 600 ft away from free-stall barns on three Ohio dairy farms during the 2014 and 2015 spring migrations. Individual swabs were used to obtain both a cloacal and external surface swab from each bird. Samples were inoculated into MacConkey broth containing cefotaxime then inoculated onto MacConkey agar with cefoxitin, cefepime, or meropenem to identify the blaCMY, blaCTX-M, and carbapenemase phenotypes, respectively. Six hundred twenty-three birds were sampled, 19 (3.0%) of which harbored bacteria with blaCMY and 32 (5.1%) harbored bacteria with blaCTX-M from either their cloacal sample or from their external swab. There was no difference in the prevalence of either gene between migratory and resident birds. Prevalence of blaCMY and blaCTX-M was higher among birds sampled immediately outside the barns compared with those sampled 600 ft away. Our results suggest that wild birds can serve as mechanical and/or biological vectors for Enterobacteriaceae with resistance to ESCs. Birds live in close contact with dairy cows and their feed, therefore, transmission locally between farms is possible. Finding a similar prevalence in migratory and nonmigratory birds suggests the potential for regional and intercontinental movement of these resistance genes via birds. [ABSTRACT FROM AUTHOR]

Published
2017
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42. Salmonellaspp. and Extended-Spectrum Cephalosporin-Resistant Escherichia coliFrequently Contaminate Broiler Chicken Transport Cages of an Organic Production Company

Author

Mollenkopf, Dixie F., De Wolf, Brittany, Feicht, Sydnee M., Cenera, Johana K., King, Christy A., van Balen, Joany C., and Wittum, Thomas E.

Abstract

AbstractAntimicrobial resistant bacteria in retail meat pose a health hazard to the public, as does contamination of these products with Salmonella. Our aim was to determine the prevalence of Salmonellaas well as Escherichia coliexpressing AmpC and extended-spectrum beta-lactamase (ESBL) resistance phenotypes contaminating broiler transport cages and fresh, retail ground chicken meat. Sterile gauze sponges were used to collect duplicate cage floor samples from transport trailers that deliver market-ready birds to a single organic poultry-processing facility. With the exception of the first visit (n= 25), 50 duplicate cage floor samples were collected using moistened sterile gauze sponges on each of nine weekly visits during May, June, and July 2013. Additionally, fresh, retail ground chicken meat was sampled at each weekly visit from an on-site retail store located at the same processing facility. A total of 425 cage swabs and 72 ground chicken aliquots from 24 retail packages were collected and screened for the presence of Salmonellaas well as E. coliexpressing resistance to extended-spectrum cephalosporins using selective culture. We recovered Salmonellafrom 26.1% of cage swab samples and 2.8% of retail meat samples. E. coliexpressing AmpC and ESBL resistance phenotypes were recovered from 84.9% and 22.6% of cage swabs and 77.8% and 11.1% of fresh, retail ground meat samples, respectively. Our results suggest that transport cages could potentially act as a source of broiler exposure to both Salmonellaand enteric bacteria resistant to important antimicrobial drugs as they are transported for entry into the food supply as fresh, retail meat products.

Published
2018
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43. Maintenance of Carbapenemase-Producing Enterobacteriaceaein a Farrow-to-Finish Swine Production System

Author

Mollenkopf, Dixie F., Mathys, Dimitria A., Feicht, Sydnee M., Stull, Jason W., Bowman, Andrew S., Daniels, Joshua B., and Wittum, Thomas E.

Abstract

AbstractCarbapenemase-producing Enterobacteriaceae(CPE) threaten both agriculture and public health. While carbapenems are restricted in food-producing animals, other β-lactams, such as ceftiofur, are frequently applied in livestock. While the relationship is not fully elucidated, ceftiofur use may provide selective pressure that promotes carbapenem resistance. Recently reported in U.S. livestock, plasmid-mediated CPE are also present in livestock in Europe and Asia. We previously reported the rare carbapenemase gene, blaIMP-64, in the environment of a large farrow-to-finish swine operation. To better understand CPE in this swine production system, in 2016 we followed a cohort of 350+ pigs over 5 months from late sow gestation to the final finishing phase. We screened both environmental and fecal samples for CPE using our selective enrichment protocol, with resulting phenotypic CPE isolates further characterized. Of 55 environmental and 109 sow fecal samples collected from a farrowing barn on our initial visit, 35 (64%) environmental and 15 (14%) sow fecal samples yielded isolates of multiple Enterobacteriaceaespecies carrying the metallo-β-lactamase gene blaIMP-64on an IncQ plasmid. The frequency of IMP-64-positive environmental (n= 32), sow fecal (n= 30), and piglet fecal swab (n = 120) samples was highest for all groups when the market pig cohort was between 1 and 10 days, with observed prevalence of 97%, 28%, and 18%, respectively. After weaning, blaIMP-64was detected in a single environmental sample from a nursery pen, with no CPE recovered in the finishing phase. Used in U.S. swine production to treat and control disease, ceftiofur is administered to piglets on this farm at birth, with males receiving a second dose at castration (≈day 7). Once introduced into animal agriculture, the common use of ceftiofur may provide the selection pressure required for CPE dissemination throughout large, intensively managed food animal populations housed in animal-dense environments.

Published
2018
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50. Organic or Antibiotic-Free Labeling Does Not Impact the Recovery of Enteric Pathogens and Antimicrobial-Resistant Escherichia colifrom Fresh Retail Chicken

Author

Mollenkopf, Dixie F., Cenera, Johana K., Bryant, Erin M., King, Christy A., Kashoma, Isaac, Kumar, Anand, Funk, Julie A., Rajashekara, Gireesh, and Wittum, Thomas E.

Abstract

AbstractWe investigated the implied health benefits of retail chicken breast labeled as “organic” or “antibiotic-free” when compared to conventional products based on frequency of contamination by Salmonellaspp., Campylobacterspp., and coliform bacteria resistant to fluoroquinolones, extended-spectrum cephalosporins, or carbapenems. We purchased 231 prepackaged chicken breasts from 99 grocery stores representing 17 retail chains in Ohio, Michigan, and Pennsylvania from June to September 2012. Ninety-six (41.5%) packages were labeled “antibiotic free” and 40 (17.3%) were labeled “organic,” with the remaining 95 (41.1%) making neither label claim. Salmonellawere recovered from 56 (24.2%) packages, and the recovery rate was not different between product types. Five percent of packages contained Salmonellacarrying the extended-spectrum cephalosporin resistance gene blaCMY-2, representing 21.4% of Salmonellaisolates. Campylobacterspp. were recovered from 10.8% of packages, with observed recovery rates similar for the three product types. Using selective media, we recovered Escherichia coliharboring blaCMY-2from over half (53.7%) of packages, with similar recovery rates for all product types. In addition, we recovered E. colicarrying blaCTX-Mfrom 6.9% of packages, and E. coliwith QRDR mutations from 8.2% of packages. Fluoroquinolone-resistant E. colirecovered using selective media were more common (p<0.05) in conventional (18.9%) compared to organic (0) and antibiotic-free (2.1%) packages. Our results indicate that, regardless of product type, fresh retail chicken breast is commonly contaminated with enteric pathogens associated with foodborne illness and commensal bacteria harboring genes conferring resistance to critically important antimicrobial drugs.

Published
2014
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