More Like this

1. Relating Antimicrobial Resistance and Virulence in Surface-Water E. coli

   https://doi.org/10.3390/microorganisms11112647  

   LaMontagne, Connor D; Christenson, Elizabeth C; Rogers, Anna T; Jacob, Megan E; Stewart, Jill R (November 2023, Microorganisms)

   The role of the environment in the emergence and spread of antimicrobial resistance (AMR) is being increasingly recognized, raising questions about the public health risks associated with environmental AMR. Yet, little is known about pathogenicity among resistant bacteria in environmental systems. Existing studies on the association between AMR and virulence are contradictory, as fitness costs and genetic co-occurrence can be opposing influences. Using Escherichia coli isolated from surface waters in eastern North Carolina, we compared virulence gene prevalence between isolates resistant and susceptible to antibiotics. We also compared the prevalence of isolates from sub-watersheds with or without commercial hog operations (CHOs). Isolates that had previously been evaluated for phenotypic AMR were paired by matching isolates resistant to any tested antibiotic with fully susceptible isolates from the same sample date and site, forming 87 pairs. These 174 isolates were evaluated by conventional PCR for seven virulence genes (bfp, fimH, cnf-1, STa (estA), EAST-1 (astA), eae, and hlyA). One gene, fimH, was found in 93.1% of isolates. Excluding fimH, at least one virulence gene was detected in 24.7% of isolates. Significant negative associations were found between resistance to at least one antibiotic and presence of at least one virulence gene, tetracycline resistance and presence of a virulence gene, resistance and STa presence, and tetracycline resistance and STa presence. No significant associations were found between CHO presence and virulence, though some sub-significant associations merit further study. This work builds our understanding of factors controlling AMR dissemination through the environment and potential health risks. 

   more » « less
2. Comparison of methods proposed for monitoring cefotaxime-resistant Escherichia coli in the water environment

   https://doi.org/10.1128/aem.02128-23  

   Calarco, Jeanette; Pruden, Amy; Harwood, Valerie J (May 2024, Applied and Environmental Microbiology)

   Semrau, Jeremy D (Ed.)

   ABSTRACT Escherichia coliis a promising subject for globally coordinated surveillance of antimicrobial resistance (AMR) in water environments due to its clinical relevance and widespread use as an indicator of fecal contamination. Cefotaxime-resistantE. coliwas recently evaluated favorably for this purpose by the World Health Organization TriCycle Protocol, which specifies tryptone bile x-glucuronide (TBX) medium and incubation at 35°C. We assessed comparability with the U.S. Environmental Protection Agency-approved method forE. coliquantification, which uses membrane-thermotolerantE. coli(mTEC) agar and incubation at 44.5°C, in terms of recovery ofE. coliand cefotaxime-resistantE. colifrom wastewater influent and surface waters. TotalE. coliconcentrations in wastewater influent were 10⁶–10⁸CFU/100 mL, while cefotaxime-resistantE. coliwere ~100-fold lower. TotalE. coliin surface waters were ~10²CFU/100 mL, and cefotaxime-resistant isolates were near the limit of detection (0.4 CFU/100 mL). Total and putative cefotaxime-resistantE. coliconcentrations did not differ significantly between media or by incubation method; however, colonies isolated on mTEC were more frequently confirmed to species (97.1%) compared to those from TBX (92.5%). Incubation in a water bath at 44.5°C significantly decreased non-specific background growth and improved confirmation frequency on both media (97.4%) compared to incubation at 35°C (92.3%). This study helps to advance globally coordinated AMR in water environments and suggests that the TriCycle Protocol is adaptable to other standard methods that may be required in different locales, while also offering a means to improve specificity by decreasing the frequency of false-positive identification of cefotaxime-resistantE. coliby modifying incubation conditions.IMPORTANCEAs antibiotic-resistant bacteria in water environments are increasingly recognized as contributors to the global antibiotic resistance crisis, the need for a monitoring subject that captures antibiotic resistance trends on a global scale increases. The World Health Organization TriCycle Protocol proposes the use of cefotaxime-resistantEscherichia coliisolated on tryptone bile x-glucuronide agar. The U.S. Environmental Protection Agency (USEPA) criteria for safe recreational waters also useE. colias an indicator but specify the use of mTEC agar at a higher incubation temperature (44.5°C vs 35°C). We assessed the comparability of these methods for isolating total and cefotaxime-resistantE. coli, finding overall good agreement and performance, but significantly higher specificity towardE. coliselection with the use of the USEPA incubation protocol and mTEC agar. This study is the first to directly compare these methods and provides evidence that the methods may be used interchangeably for global surveillance of antibiotic resistance in the environment. 

   more » « less
3. Atlanta E. coli data, 2019-2023

   https://doi.org/10.4211/hs.30600d19187f4a0cb3489908e07e652d  

   Ledford, Sarah (August 2025, HydroShare)

   Urban streams and rivers have chronic bacteria contamination in the United States, coming from multiple sources, following a variety of flowpaths to the waterway, and with differing downstream fates. Bacteria from human sewage, estimated through measures of Escherichia coli, pose the highest risk to human health. We analyzed four years of E. coli monitoring by community science groups to look for spatial and temporal drivers of E. coli densities in watersheds in the urban core of metro Atlanta, GA, with a wide range of racial and economic diversity as well as persistent patterns of segregation and racialized inequality. These watersheds are spaces of environmental injustice, with disproportionate impacts for lower-wealth and predominantly Black communities from flooding, soil contamination, and air pollution. While there were minimal differences in E. coli between watersheds with different Black and white populations, individual sites could be identified as hot and cold spots of contamination. Storm events increased E. coli at most sites, indicating a combination of runoff and sediment-sorbed E. coli explains about 50% of the temporal variability in E. coli densities. Long-term median E. coli levels were not strongly correlated to land cover or socio-demographic characteristics of the contributing watershed, but E. coli variability was lower in less densely urbanized areas. Temporal and spatial distributions of E. coli are controlled by complex interactions between sources and hydrologic transport that vary across watersheds. While direct correlations to racial demographics were not observed, the interactions between sewage as one environmental harm and the many others (air quality, soil quality, prison-industrial complex, etc.) present in minority and low-income urban communities emphasize the oversized burden environmental justice communities carry. 

   more » « less
4. Extended Spectrum β-Lactamase Activity and Cephalosporin Resistance in Escherichia coli from U.S. Mid-Atlantic Surface and Reclaimed Water

   https://doi.org/10.1128/aem.00837-22  

   Solaiman, Sultana; Handy, Eric; Brinks, Taylor; Goon, Kasey; Bollinger, Chris; Sapkota, Amy R.; Sharma, Manan; Micallef, Shirley A. (August 2022, Applied and Environmental Microbiology)

   Villanueva, Laura (Ed.)

   ABSTRACT Phylogenetic distribution and extended spectrum β-lactamase (ESBL) activity of Escherichia coli recovered from surface and reclaimed water in the mid-Atlantic U.S. were evaluated. Among 488 isolates, phylogroups B1 and A were the most and least prevalent, respectively. Water type, but not season, affected phylogroup distribution. The likelihood of detecting group A isolates was higher in reclaimed than pond ( P <  0.01), freshwater river ( P <  0.01) or brackish river (P <  0.05) water. Homogeneity in group distribution was lowest in pond water, where group B1 comprised 50% of isolates. Only 16 (3.3%) isolates exhibited phenotypic resistance to one or more cephalosporins tested and only four had ESBL activity, representing groups B1, B2 isolates, and D. Phylogroup was a factor in antimicrobial resistance ( P <  0.05), with group A (8.7%) and D (1.6%) exhibiting the highest and lowest rates. Resistance to cefoxitin was the most prevalent. Multi- versus single drug resistance was affected by phylogroup ( P <  0.05) and more likely in groups D and B1 than A which carried resistance to cefoxitin only. The most detected β-lactam resistance genes were bla CMY-2 and bla TEM . Water type was a factor for bla CTX-M gene detection ( P <  0.05). Phenotypic resistance to cefotaxime, ceftriaxone, cefuroxime and ceftazidime, and genetic determinants for ESBL-mediated resistance were found predominantly in B2 and D isolates from rivers and reclaimed water. Overall, ESBL activity and cephalosporin resistance in reclaimed and surface water isolates were low. Integrating data on ESBL activity and β-lactam resistance among E. coli populations can inform decisions on safety of irrigation water sources and One Health. IMPORTANCE Extended spectrum β-lactamase (ESBL) producing bacteria, that are resistant to a broad range of antimicrobial agents, are spreading in the environment but data remain scarce. ESBL-producing Escherichia coli infections in the community are on the rise. This work was conducted to assess presence of ESBL-producing E. coli in water that could be used for irrigation of fresh produce. The study provides the most extensive evaluation of ESBL-producing E. coli in surface and reclaimed water in the mid-Atlantic United States. The prevalence of ESBL producers was low and phenotypic resistance to cephalosporins (types of β-lactam antibiotics) was affected by season but not water type. Data on antimicrobial resistance among E. coli populations in water can inform decisions on safety of irrigation water sources and One Health. 

   more » « less
5. Molecular epidemiology and pathogenomics of extended-spectrum beta-lactamase producing- Escherichia coli and - Klebsiella pneumoniae isolates from bulk tank milk in Tennessee, USA

   https://doi.org/10.3389/fmicb.2023.1283165  

   Gelalcha, Benti D; Mohammed, Ruwaa I; Gelgie, Aga E; Kerro_Dego, Oudessa (November 2023, Frontiers in Microbiology)

   IntroductionThe rise in extended-spectrum beta-lactamase (ESBL)-producingEnterobacteriaceaein dairy cattle farms poses a risk to human health as they can spread to humans through the food chain, including raw milk. This study was designed to determine the status, antimicrobial resistance, and pathogenic potential of ESBL-producing -E. coliand -Klebsiellaspp. isolates from bulk tank milk (BTM). MethodsThirty-three BTM samples were collected from 17 dairy farms and screened for ESBL-E. coliand -Klebsiellaspp. on CHROMagar ESBL plates. All isolates were confirmed by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) and subjected to antimicrobial susceptibility testing and whole genome sequencing (WGS). ResultsTen presumptive ESBL-producing bacteria, eightE. coli, and twoK. pneumoniaewere isolated. The prevalence of ESBL-E. coliand -K. pneumoniaein BTM was 21.2% and 6.1%, respectively. ESBL-E. coliwere detected in 41.2% of the study farms. Seven of the ESBL-E. coliisolates were multidrug resistant (MDR). The two ESBL-producingK. pneumoniaeisolates were resistant to ceftriaxone. Seven ESBL-E. colistrains carry thebla_CTX-Mgene, and five of them co-harboredbla_TEM-1. ESBL-E. colico-harboredbla_CTX-Mwith other resistance genes, includingqnrB19,tet(A),aadA1,aph(3’’)-Ib,aph(6)-Id),floR,sul2, and chromosomal mutations (gyrA, gyrB, parC, parE, and pmrB). MostE. coliresistance genes were associated with mobile genetic elements, mainly plasmids. Six sequence types (STs) ofE. coliwere detected. All ESBL-E. coliwere predicted to be pathogenic to humans. Four STs (three ST10 and ST69) were high-risk clones ofE. coli. Up to 40 virulence markers were detected in allE. coliisolates. One of theK. pneumoniaewas ST867; the other was novel strain.K. pneumoniaeisolates carried three types of beta-lactamase genes (bla_CTX-M,bla_TEM-1andbla_SHV). The novelK. pneumoniaeST also carried a novel IncFII(K) plasmid ST. ConclusionDetection of high-risk clones of MDR ESBL-E. coliand ESBL-K. pneumoniaein BTM indicates that raw milk could be a reservoir of potentially zoonotic ESBL-E. coliand -K. pneumoniae. 

   more » « less