scholarly journals Molecular Characterization of Resistance to Extended-Spectrum Cephalosporins in Clinical Escherichia coli Isolates from Companion Animals in the United States

2011 ◽  
Vol 55 (12) ◽  
pp. 5666-5675 ◽  
Author(s):  
Bashar W. Shaheen ◽  
Rajesh Nayak ◽  
Steven L. Foley ◽  
Ohgew Kweon ◽  
Joanna Deck ◽  
...  

ABSTRACTResistance to extended-spectrum cephalosporins (ESC) among members of the familyEnterobacteriaceaeoccurs worldwide; however, little is known about ESC resistance inEscherichia colistrains from companion animals. Clinical isolates ofE. coliwere collected from veterinary diagnostic laboratories throughout the United States from 2008 to 2009.E. coliisolates (n= 54) with reduced susceptibility to ceftazidime or cefotaxime (MIC ≥ 16 μg/ml) and extended-spectrum-β-lactamase (ESBL) phenotypes were analyzed. PCR and sequencing were used to detect mutations in ESBL-encoding genes and the regulatory region of the chromosomal geneampC. Conjugation experiments and plasmid identification were conducted to examine the transferability of resistance to ESCs. All isolates carried theblaCTX-M-1-group β-lactamase genes in addition to one or more of the following β-lactamase genes:blaTEM,blaSHV-3,blaCMY-2,blaCTX-M-14-like, andblaOXA-1.DifferentblaTEMsequence variants were detected in some isolates (n= 40). Three isolates harbored ablaTEM-181gene with a novel mutation resulting in an Ala184Val substitution. Approximately 78% of the isolates had mutations in promoter/attenuator regions of the chromosomal geneampC, one of which was a novel insertion of adenine between bases −28 and −29. Plasmids ranging in size from 11 to 233 kbp were detected in the isolates, with a common plasmid size of 93 kbp identified in 60% of isolates. Plasmid-mediated transfer of β-lactamase genes increased the MICs (≥16-fold) of ESCs for transconjugants. Replicon typing among isolates revealed the predominance of IncI and IncFIA plasmids, followed by IncFIB plasmids. This study shows the emergence of conjugative plasmid-borne ESBLs amongE. colistrains from companion animals in the United States, which may compromise the effective therapeutic use of ESCs in veterinary medicine.

mSphere ◽  
2020 ◽  
Vol 5 (5) ◽  
Author(s):  
Shivdeep Singh Hayer ◽  
Seunghyun Lim ◽  
Samuel Hong ◽  
Ehud Elnekave ◽  
Timothy Johnson ◽  
...  

ABSTRACT Fluoroquinolones and cephalosporins are critically important antimicrobial classes for both human and veterinary medicine. We previously found a drastic increase in enrofloxacin resistance in clinical Escherichia coli isolates collected from diseased pigs from the United States over 10 years (2006 to 2016). However, the genetic determinants responsible for this increase have yet to be determined. The aim of the present study was to identify and characterize the genetic basis of resistance against fluoroquinolones (enrofloxacin) and extended-spectrum cephalosporins (ceftiofur) in swine E. coli isolates using whole-genome sequencing (WGS). blaCMY-2 (carried by IncA/C2, IncI1, and IncI2 plasmids), blaCTX-M (carried by IncF, IncHI2, and IncN plasmids), and blaSHV-12 (carried by IncHI2 plasmids) genes were present in 87 (82.1%), 19 (17.9%), and 3 (2.83%) of the 106 ceftiofur-resistant isolates, respectively. Of the 110 enrofloxacin-resistant isolates, 90 (81.8%) had chromosomal mutations in gyrA, gyrB, parA, and parC genes. Plasmid-mediated quinolone resistance genes [qnrB77, qnrB2, qnrS1, qnrS2, and aac-(6)-lb′-cr] borne on ColE, IncQ2, IncN, IncF, and IncHI2 plasmids were present in 24 (21.8%) of the enrofloxacin-resistant isolates. Virulent IncF plasmids present in swine E. coli isolates were highly similar to epidemic plasmids identified globally. High-risk E. coli clones, such as ST744, ST457, ST131, ST69, ST10, ST73, ST410, ST12, ST127, ST167, ST58, ST88, ST617, ST23, etc., were also found in the U.S. swine population. Additionally, the colistin resistance gene (mcr-9) was present in several isolates. This study adds valuable information regarding resistance to critical antimicrobials with implications for both animal and human health. IMPORTANCE Understanding the genetic mechanisms conferring resistance is critical to design informed control and preventive measures, particularly when involving critically important antimicrobial classes such as extended-spectrum cephalosporins and fluoroquinolones. The genetic determinants of extended-spectrum cephalosporin and fluoroquinolone resistance were highly diverse, with multiple plasmids, insertion sequences, and genes playing key roles in mediating resistance in swine Escherichia coli. Plasmids assembled in this study are known to be disseminated globally in both human and animal populations and environmental samples, and E. coli in pigs might be part of a global reservoir of key antimicrobial resistance (AMR) elements. Virulent plasmids found in this study have been shown to confer fitness advantages to pathogenic E. coli strains. The presence of international, high-risk zoonotic clones provides worrisome evidence that resistance in swine isolates may have indirect public health implications, and the swine population as a reservoir for these high-risk clones should be continuously monitored.


2012 ◽  
Vol 56 (5) ◽  
pp. 2364-2370 ◽  
Author(s):  
James R. Johnson ◽  
Carl Urban ◽  
Scott J. Weissman ◽  
James H. Jorgensen ◽  
James S. Lewis ◽  
...  

ABSTRACTEscherichia colisequence type ST131 (from phylogenetic group B2), often carrying the extended-spectrum-β-lactamase (ESBL) geneblaCTX-M-15, is an emerging globally disseminated pathogen that has received comparatively little attention in the United States. Accordingly, a convenience sample of 351 ESBL-producingE. coliisolates from 15 U.S. centers (collected in 2000 to 2009) underwent PCR-based phylotyping and detection of ST131 andblaCTX-M-15. A total of 200 isolates, comprising 4 groups of 50 isolates each that were (i)blaCTX-M-15negative non-ST131, (ii)blaCTX-M-15positive non-ST131, (iii)blaCTX-M-15negative ST131, or (iv)blaCTX-M-15positive ST131, also underwent virulence genotyping, antimicrobial susceptibility testing, and pulsed-field gel electrophoresis (PFGE). Overall, 201 (57%) isolates exhibitedblaCTX-M-15, whereas 165 (47%) were ST131. ST131 accounted for 56% ofblaCTX-M-15-positive- versus 35% ofblaCTX-M-15-negative isolates (P< 0.001). Whereas ST131 accounted for 94% of the 175 total group B2 isolates, non-ST131 isolates were phylogenetically distributed byblaCTX-M-15status, with groups A (blaCTX-M-15-positive isolates) and D (blaCTX-M-15-negative isolates) predominating. BothblaCTX-M-15and ST131 occurred at all participating centers, were recovered from children and adults, increased significantly in prevalence post-2003, and were associated with molecularly inferred virulence. Compared with non-ST131 isolates, ST131 isolates had higher virulence scores, distinctive virulence profiles, and more-homogeneous PFGE profiles.blaCTX-M-15was associated with extensive antimicrobial resistance and ST131 with fluoroquinolone resistance. Thus,E. coliST131 andblaCTX-M-15are emergent, widely distributed, and predominant among ESBL-positiveE. colistrains in the United States, among children and adults alike. Enhanced virulence and antimicrobial resistance have likely promoted the epidemiological success of these emerging public health threats.


2017 ◽  
Vol 83 (6) ◽  
Author(s):  
James R. Johnson ◽  
Stephen B. Porter ◽  
Brian Johnston ◽  
Paul Thuras ◽  
Sarah Clock ◽  
...  

ABSTRACT Chicken meat products are hypothesized to be vehicles for transmitting antimicrobial-resistant and extraintestinal pathogenic Escherichia coli (ExPEC) to consumers. To reassess this hypothesis in the current era of heightened concerns about antimicrobial use in food animals, we analyzed 175 chicken-source E. coli isolates from a 2013 Consumer Reports national survey. Isolates were screened by PCR for ExPEC-defining virulence genes. The 25 ExPEC isolates (12% of 175) and a 2:1 randomly selected set of 50 non-ExPEC isolates were assessed for their phylogenetic/clonal backgrounds and virulence genotypes for comparison with their resistance profiles and the claims on the retail packaging label (“organic,” “no antibiotics,” and “natural”). Compared with the findings for non-ExPEC isolates, the group of ExPEC isolates had a higher prevalence of phylogroup B2 isolates (44% versus 4%; P < 0.001) and a lower prevalence of phylogroup A isolates (4% versus 30%; P = 0.001), a higher prevalence of multiple individual virulence genes, higher virulence scores (median, 11 [range, 4 to 16] versus 8 [range, 1 to 14]; P = 0.001), and higher resistance scores (median, 4 [range, 0 to 8] versus 3 [range, 0 to 10]; P < 0.001). All five isolates of sequence type 131 (ST131) were ExPEC (P = 0.003), were as extensively resistant as the other isolates tested, and had higher virulence scores than the other isolates tested (median, 12 [range, 11 to 13] versus 8 [range, 1 to 16]; P = 0.005). Organic labeling predicted lower resistance scores (median, 2 [range, 0 to 3] versus 4 [range, 0 to 10]; P = 0.008) but no difference in ExPEC status or virulence scores. These findings document a persisting reservoir of extensively antimicrobial-resistant ExPEC isolates, including isolates from ST131, in retail chicken products in the United States, suggesting a potential public health threat. IMPORTANCE We found that among Escherichia coli isolates from retail chicken meat products purchased across the United States in 2013 (many of these isolates being extensively antibiotic resistant), a minority had genetic profiles suggesting an ability to cause extraintestinal infections in humans, such as urinary tract infection, implying a risk of foodborne disease. Although isolates from products labeled “organic” were less extensively antibiotic resistant than other isolates, they did not appear to be less virulent. These findings suggest that retail chicken products in the United States, even if they are labeled “organic,” pose a potential health threat to consumers because they are contaminated with extensively antibiotic-resistant and, presumably, virulent E. coli isolates.


2019 ◽  
Vol 8 (34) ◽  
Author(s):  
Gregory H. Tyson ◽  
Cong Li ◽  
Olgica Ceric ◽  
Renate Reimschuessel ◽  
Stephen Cole ◽  
...  

The carbapenem resistance gene bla NDM-5 was identified in an Escherichia coli strain isolated from a dog. We report here the complete genome sequence of this E. coli strain; the bla NDM-5 gene was present on a large IncFII multidrug-resistant plasmid. This is the first bla NDM-5-carrying E. coli strain from an animal in the United States.


2011 ◽  
Vol 78 (5) ◽  
pp. 1615-1618 ◽  
Author(s):  
Lydia V. Rump ◽  
Sonya Bodeis-Jones ◽  
Jason Abbott ◽  
Shaohua Zhao ◽  
Julie Kase ◽  
...  

ABSTRACTEscherichia coliO104 isolates collected from different sources in the United States were examined for virulence genes typical of enterohemorrhagicE. coliand those identified in the O104:H4 isolate associated with the 2011 German outbreak. The unexpected presence of virulence markers in these isolates highlights the importance of screening unusual and potentially pathogenic Shiga toxin-producingE. coliserotypes.


2015 ◽  
Vol 59 (6) ◽  
pp. 3606-3610 ◽  
Author(s):  
Sibylle H. Lob ◽  
Krystyna M. Kazmierczak ◽  
Robert E. Badal ◽  
Meredith A. Hackel ◽  
Samuel K. Bouchillon ◽  
...  

ABSTRACTAntimicrobial resistance inEnterobacteriaceae, including resistance to carbapenems, is increasing worldwide. However, using U.S. Study for Monitoring Antimicrobial Resistance Trends (SMART) data for 2009 to 2013, no statistically significant decreasing susceptibility trends were found overall forEscherichia coliisolates from patients with intra-abdominal infections. In the subset of isolates from community-associated infections, susceptibility to levofloxacin decreased significantly and the increasing rate of multidrug-resistantE. coliapproached statistical significance. In 2013, ertapenem, imipenem, and amikacin showed the highest susceptibility rates (≥99%) and fluoroquinolones the lowest (<70%). The 10 non-ertapenem-susceptible isolates (0.3% of allE. coliisolates) encoded one or more carbapenemases, extended-spectrum β-lactamases (ESBLs), AmpC β-lactamases, or non-ESBL β-lactamases.


2017 ◽  
Vol 61 (8) ◽  
Author(s):  
James R. Johnson ◽  
Stephen Porter ◽  
Paul Thuras ◽  
Mariana Castanheira

ABSTRACT The H30 subclone of Escherichia coli sequence type 131 (ST131-H30) has become the leading antimicrobial resistance E. coli lineage in the United States and often exhibits resistance to one or both of the two key antimicrobial classes for treating Gram-negative infections, extended-spectrum cephalosporins (ESCs) and fluoroquinolones (FQs). However, the timing of and reasons for its recent emergence are inadequately defined. Accordingly, from E. coli clinical isolates collected systematically across the United States by the SENTRY Antimicrobial Surveillance Program in 2000, 2003, 2006, and 2009, 234 isolates were selected randomly, stratified by year, within three resistance categories: (i) ESC-reduced susceptibility, regardless of FQ phenotype (ESC-RS); (ii) FQ resistance, ESC susceptible (FQ-R); and (iii) FQ susceptible, ESC susceptible (FQ-S). Susceptibility profiles, phylogroup, ST, ST131 subclone, and virulence genotypes were determined, and temporal trends and between-variable associations were assessed statistically. From 2000 to 2006, concurrently with the emergence of ESC-RS and FQ-R strains, the prevalence of (virulence-associated) phylogroup B2 among such strains also rose dramatically, due entirely to rapid emergence of ST131, especially H30. By 2009, H30 was the dominant E. coli lineage overall (22%), accounting for a median of 43% of all single-agent and multidrug resistance (68% for ciprofloxacin). H30's emergence increased the net virulence gene content of resistant (especially FQ-R) isolates, giving stable overall virulence gene scores despite an approximately 4-fold expansion of the historically less virulent resistant population. These findings define more precisely the timing and tempo of H30's emergence in the United States, identify possible reasons for it, and suggest potential consequences, including more frequent and/or aggressive antimicrobial-resistant infections.


2016 ◽  
Vol 60 (7) ◽  
pp. 4073-4081 ◽  
Author(s):  
Kalyan D. Chavda ◽  
Liang Chen ◽  
Michael R. Jacobs ◽  
Robert A. Bonomo ◽  
Barry N. Kreiswirth

ABSTRACTThe emergence and spread ofKlebsiella pneumoniaecarbapenemase (KPC) amongEnterobacteriaceaepresents a major public health threat to the world. Although not as common as inK. pneumoniae, KPC is also found inEscherichia colistrains. Here, we genetically characterized 9 carbapenem-resistantE. colistrains isolated from six hospitals in the United States and completely sequenced theirblaKPC-harboring plasmids. The nine strains were isolated from different geographical locations and belonged to 8 differentE. colisequence types. SevenblaKPC-harboring plasmids belonged to four different known incompatibility groups (IncN, -FIA, -FIIK2, and -FIIK1) and ranged in size from ∼16 kb to ∼241 kb. In this analysis, we also identified two plasmids that have novel replicons: (i) pBK28610, which is similar to p34978-3 with an insertion of Tn4401b, and (ii) pBK31611, which does not have an apparent homologue in the GenBank database. Moreover, we report the emergence of a pKP048-like plasmid, pBK34397, inE. coliin the United States. Meanwhile, we also found examples of interspecies spread ofblaKPCplasmids, as pBK34592 is identical to pBK30683, isolated fromK. pneumoniae. In addition, we discovered examples of acquisition (pBK32602 acquired an ∼46-kb fragment including a novel replication gene, along with Tn4401band other resistance genes) and/or loss (pKpQIL-Ec has a 14.5-kb deletion compared to pKpQIL-10 and pBK33689) of DNA, demonstrating the plasticity of these plasmids and their rapid evolution in the clinic. Overall, our study shows that the spread ofblaKPC-producingE. coliis largely due to horizontal transfer ofblaKPC-harboring plasmids and related mobile elements into diverse genetic backgrounds.


2004 ◽  
Vol 48 (2) ◽  
pp. 533-537 ◽  
Author(s):  
M. Alvarez ◽  
J. H. Tran ◽  
N. Chow ◽  
G. A. Jacoby

ABSTRACT A sample of 752 resistant Klebsiella pneumoniae, Klebsiella oxytoca, and Escherichia coli strains from 70 sites in 25 U.S. states and the District of Columbia was examined for transmissibility of resistance to ceftazidime and the nature of the plasmid-mediated β-lactamase involved. Fifty-nine percent of the K. pneumoniae, 24% of the K. oxytoca, and 44% of the E. coli isolates transferred resistance to ceftazidime. Plasmids encoding AmpC-type β-lactamase were found in 8.5% of the K. pneumoniae samples, 6.9% of the K. oxytoca samples, and 4% of the E. coli samples, at 20 of the 70 sites and in 10 of the 25 states. ACT-1 β-lactamase was found at eight sites, four of which were near New York City, where the ACT-1 enzyme was first discovered; ACT-1 β-lactamase was also found in Massachusetts, Pennsylvania, and Virginia. FOX-5 β-lactamase was also found at eight sites, mainly in southeastern states but also in New York. Two E. coli strains produced CMY-2, and one K. pneumoniae strain produced DHA-1 β-lactamase. Pulsed-field gel electrophoresis and plasmid analysis suggested that AmpC-mediated resistance spread both by strain and plasmid dissemination. All AmpC β-lactamase-containing isolates were resistant to cefoxitin, but so were 11% of strains containing transmissible SHV- and TEM-type extended-spectrum β-lactamases. A β-lactamase inhibitor test was helpful in distinguishing the two types of resistance but was not definitive since 24% of clinical isolates producing AmpC β-lactamase had a positive response to clavulanic acid. Coexistence of AmpC and extended-spectrum β-lactamases was the main reason for these discrepancies. Plasmid-mediated AmpC-type enzymes are thus responsible for an appreciable fraction of resistance in clinical isolates of Klebsiella spp. and E. coli, are disseminated around the United States, and are not so easily distinguished from other enzymes that mediate resistance to oxyimino-β-lactams.


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