scholarly journals Virulence of Escherichia coli Clinical Isolates in a Murine Sepsis Model in Relation to Sequence Type ST131 Status, Fluoroquinolone Resistance, and Virulence Genotype

2012 ◽  
Vol 80 (4) ◽  
pp. 1554-1562 ◽  
Author(s):  
James R. Johnson ◽  
Stephen B. Porter ◽  
George Zhanel ◽  
Michael A. Kuskowski ◽  
Erick Denamur
Keyword(s):  
Escherichia Coli ◽  
Study Groups ◽  
Sequence Type ◽  
Clinical Isolates ◽  
Fluoroquinolone Resistance ◽  
Content Type ◽  
E Coli ◽  
Sepsis Model ◽  
Virulence Potential ◽  
Wide Range

ABSTRACTEscherichia colisequence type ST131 (O25b:H4) has emerged over the past decade as a globally disseminated, multidrug-resistant pathogen. Unlike traditional antimicrobial-resistantE. coli, ST131 derives from virulence-associated phylogenetic group B2 and exhibits extraintestinal virulence factors. This, plus preliminary evidence of virulence in experimental animals, has suggested that ST131's epidemic emergence may be due to high virulence potential, compared with otherE. colitypes. To test this hypothesis, we compared a large number of matched ST131 and non-ST131E. coliclinical isolates, both fluoroquinolone resistant and susceptible, plus isolates from classic extraintestinal pathogenicE. coli(ExPEC) sequence types (STs) and case report ST131 household transmission isolates, for virulence in a mouse subcutaneous sepsis model. Overall, in mice, the study isolates produced a wide range of lethality and clinical illness. However, neither ST131 status nor fluoroquinolone phenotype correlated with this diversity of illness severity, which occurred within each of the 6 study groups. In contrast, multiple known or suspected ExPEC virulence genes, includingpap(P fimbriae),vat(vacuolating toxin),kpsMII (group 2 capsule),ibeA(invasion of brain endothelium), andclbB/N(colibactin synthesis), plus molecularly defined ExPEC status, were significantly associated with virulence. These findings point away from ST131 isolates as having higher virulence potential compared with otherE. colitypes in causing invasive extraintestinal infections and suggest instead that ST131's epidemiological success may reflect enhanced fitness for upstream steps in pathogenesis or in colonization and transmission. Additionally, the extensive within-ST virulence diversity suggests an opportunity to compare closely related strains to identify the responsible genetic determinants.

scholarly journals Rapid Identification of Different Escherichia coli Sequence Type 131 Clades

2017 ◽  
Vol 61 (8) ◽  
Author(s):  
Yasufumi Matsumura ◽  
Johann D. D. Pitout ◽  
Gisele Peirano ◽  
Rebekah DeVinney ◽  
Taro Noguchi ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Epidemiological Studies ◽  
Rapid Identification ◽  
Sequence Type ◽  
Fluoroquinolone Resistance ◽  
Pcr Assay ◽  
Content Type ◽  
E Coli ◽  
Multiplex Pcr Assay ◽  
Clade C

ABSTRACT Escherichia coli sequence type 131 (ST131) is a pandemic clonal lineage that is responsible for the global increase in fluoroquinolone resistance and extended-spectrum-β-lactamase (ESBL) producers. The members of ST131 clade C, especially subclades C2 and C1-M27, are associated with ESBLs. We developed a multiplex conventional PCR assay with the ability to detect all ST131 clades (A, B, and C), as well as C subclades (C1-M27, C1-nM27 [C1-non-M27], and C2). To validate the assay, we used 80 ST131 global isolates that had been fully sequenced. We then used the assay to define the prevalence of each clade in two Japanese collections consisting of 460 ESBL-producing E. coli ST131 (2001-12) and 329 E. coli isolates from extraintestinal sites (ExPEC) (2014). The assay correctly identified the different clades in all 80 global isolates: clades A (n = 12), B (n = 12), and C, including subclades C1-M27 (n = 16), C1-nM27 (n = 20), C2 (n = 17), and other C (n = 3). The assay also detected all 565 ST131 isolates in both collections without any false positives. Isolates from clades A (n = 54), B (n = 23), and C (n = 483) corresponded to the O serotypes and the fimH types of O16-H41, O25b-H22, and O25b-H30, respectively. Of the 483 clade C isolates, C1-M27 was the most common subclade (36%), followed by C1-nM27 (32%) and C2 (15%). The C1-M27 subclade with bla CTX-M-27 became especially prominent after 2009. Our novel multiplex PCR assay revealed the predominance of the C1-M27 subclade in recent Japanese ESBL-producing E. coli isolates and is a promising tool for epidemiological studies of ST131.

scholarly journals Variation in Resistance Traits, Phylogenetic Backgrounds, and Virulence Genotypes among Escherichia coli Clinical Isolates from Adjacent Hospital Campuses Serving Distinct Patient Populations

2015 ◽  
Vol 59 (9) ◽  
pp. 5331-5339 ◽  
Author(s):  
Sarah M. Drawz ◽  
Stephen Porter ◽  
Michael A. Kuskowski ◽  
Brian Johnston ◽  
Connie Clabots ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Virulence Gene ◽  
Clinical Isolates ◽  
Fluoroquinolone Resistance ◽  
Esbl Production ◽  
Content Type ◽  
E Coli ◽  
Children's Hospital ◽  
High Acuity ◽  
Children’S Hospital

ABSTRACTEscherichia colisequence type 13 (ST131), an emergent cause of multidrug-resistant extraintestinal infections, has important phylogenetic subsets, notably theH30 andH30Rx subclones, with distinctive resistance profiles and, possibly, clinical associations. To clarify the local prevalence of these ST131 subclones and their associations with antimicrobial resistance, ecological source, and virulence traits, we extensively characterized 233 consecutiveE. coliclinical isolates (July and August 2013) from the University of Minnesota Medical Center-Fairview Infectious Diseases and Diagnostic Laboratory, Minneapolis, MN, which serves three adjacent facilities (a children's hospital and low- and high-acuity adult facilities). ST131 accounted for 26% of the study isolates (more than any other clonal group), was distributed similarly by facility, and was closely associated with ciprofloxacin resistance and extended-spectrum β-lactamase (ESBL) production. TheH30 andH30Rx subclones accounted for most ST131 isolates and for the association of ST131 with fluoroquinolone resistance and ESBL production. Unlike ST131per se, these subclones were distributed differentially by hospital, being most prevalent at the high-acuity adult facility and were absent from the children's hospital. The virulence gene profiles of ST131 and its subclones were distinctive and more extensive than those of other fluoroquinolone-resistant or ESBL-producing isolates. Within ST131,blaCTX-M-15was confined toH30Rx isolates and otherblaCTX-Mvariants to non-RxH30 isolates. Pulsed-field gel electrophoresis documented a predominance of globally distributed pulsotypes and no local outbreak pattern. These findings help clarify the epidemiology, ecology, and bacterial correlates of theH30 andH30Rx ST131 subclones by documenting a high overall prevalence but significant segregation by facility, strong associations with fluoroquinolone resistance and specific ESBL variants, and distinctive virulence gene associations that may confer fitness advantages over other resistantE. coli.

scholarly journals Intensity and Mechanisms of Fluoroquinolone Resistance within theH30 andH30Rx Subclones of Escherichia coli Sequence Type 131 Compared with Other Fluoroquinolone-Resistant E. coli

2015 ◽  
Vol 59 (8) ◽  
pp. 4471-4480 ◽  
Author(s):  
James R. Johnson ◽  
Brian Johnston ◽  
Michael A. Kuskowski ◽  
Evgeni V. Sokurenko ◽  
Veronika Tchesnokova
Keyword(s):  
Escherichia Coli ◽  
Efflux Pump ◽  
Resistance Mechanisms ◽  
Sequence Type ◽  
Fluoroquinolone Resistance ◽  
Solvent Tolerance ◽  
Organic Solvent Tolerance ◽  
Content Type ◽  
E Coli ◽  
Pump Activity

ABSTRACTThe recent expansion of theH30 subclone ofEscherichia colisequence type 131 (ST131) and its CTX-M-15-associatedH30Rx subset remains unexplained. Although ST131H30 typically exhibits fluoroquinolone resistance, so do multiple otherE. colilineages that have not expanded similarly. To determine whetherH30 isolates have more intense fluoroquinolone resistance than other fluoroquinolone-resistantE. coliisolates and to identify possible mechanisms, we determined the MICs for four fluoroquinolones (ciprofloxacin, levofloxacin, moxifloxacin, and norfloxacin) among 89 well-characterized, genetically diverse fluoroquinolone-resistantE. coliisolates (48 non-H30 and 41H30 [23H30Rx and 18H30 non-Rx]). We compared the MICs with theH30 andH30Rx status, the presence/number of nonsynonymous mutations ingyrA,parC, andparE, the presence ofaac(6′)-1b-cr(an aminoglycoside/fluoroquinolone agent-modifying enzyme), and the efflux pump activity (measured as organic solvent tolerance [OST]). Among 1,518 recentE. coliclinical isolates, ST131H30 predominated clonally, both overall and among the fluoroquinolone-resistant isolates. Among the 89 study isolates, compared with non-H30 isolates,H30 isolates exhibited categorically higher MICs for all four fluoroquinolone agents, higher absolute ciprofloxacin and norfloxacin MICs, more nonsynonymous mutations ingyrA,parC, andparE(specificallygyrAD87N,parCE84V, andparEI529L), and a numerically higher prevalence of (H30Rx-associated)aac(6′)-1b-crbut lower OST scores. All putative resistance mechanisms were significantly associated with the MICs [foraac(6′)-1b-cr: ciprofloxacin and norfloxacin only].parCD87N corresponded with ST131H30 andparEI529L with ST131 generally. Thus, more intense fluoroquinolone resistance may provide ST131H30, especiallyH30Rx [ifaac(6′)-1b-crpositive], with subtle fitness advantages over other fluoroquinolone-resistantE. colistrains. This urges both parsimonious fluoroquinolone use and a search for other fitness-enhancing traits within ST131H30.

scholarly journals Draft Genome Sequence of a Multidrug-Resistant Escherichia coli Sequence Type 1193 Pandemic Clone Isolated from Wastewater in Austria

2021 ◽  
Vol 10 (37) ◽  
Author(s):  
Adriana Cabal ◽  
Nadine Peischl ◽  
Gerhard Rab ◽  
Anna Stöger ◽  
Burkhard Springer ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Genome Sequence ◽  
Draft Genome ◽  
Treatment Plant ◽  
Multidrug Resistant ◽  
Sequence Type ◽  
Draft Genome Sequence ◽  
Fluoroquinolone Resistance ◽  
Content Type ◽  
E Coli

Extraintestinal Escherichia coli sequence type 1193 (ST1193) is an important source of fluoroquinolone resistance, which has emerged in recent years. We report the first draft genome sequence and annotation of a multidrug-resistant E. coli ST1193 strain obtained from a wastewater treatment plant in Austria.

scholarly journals Tigecycline Nonsusceptibility Occurs Exclusively in Fluoroquinolone-Resistant Escherichia coli Clinical Isolates, Including the Major Multidrug-Resistant Lineages O25b:H4-ST131-H30R and O1-ST648

2016 ◽  
Vol 61 (2) ◽  
Author(s):  
Toyotaka Sato ◽  
Yuuki Suzuki ◽  
Tsukasa Shiraishi ◽  
Hiroyuki Honda ◽  
Masaaki Shinagawa ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Parental Strain ◽  
Efflux Pump ◽  
Multidrug Resistant ◽  
Clinical Isolates ◽  
Fluoroquinolone Resistance ◽  
Content Type ◽  
E Coli ◽  
Line Drug

ABSTRACT Tigecycline (TGC) is a last-line drug for multidrug-resistant Enterobacteriaceae. We investigated the mechanism(s) underlying TGC nonsusceptibility (TGC resistant/intermediate) in Escherichia coli clinical isolates. The MIC of TGC was determined for 277 fluoroquinolone-susceptible isolates (ciprofloxacin [CIP] MIC, <0.125 mg/liter) and 194 fluoroquinolone-resistant isolates (CIP MIC, >2 mg/liter). The MIC50 and MIC90 for TGC in fluoroquinolone-resistant isolates were 2-fold higher than those in fluoroquinolone-susceptible isolates (MIC50, 0.5 mg/liter versus 0.25 mg/liter; MIC90, 1 mg/liter versus 0.5 mg/liter, respectively). Two fluoroquinolone-resistant isolates (O25b:H4-ST131-H30R and O125:H37-ST48) were TGC resistant (MICs of 4 and 16 mg/liter, respectively), and four other isolates of O25b:H4-ST131-H30R and an isolate of O1-ST648 showed an intermediate interpretation (MIC, 2 mg/liter). No TGC-resistant/intermediate strains were found among the fluoroquinolone-susceptible isolates. The TGC-resistant/intermediate isolates expressed higher levels of acrA and acrB and had lower intracellular TGC concentrations than susceptible isolates, and they possessed mutations in acrR and/or marR. The MICs of acrAB-deficient mutants were markedly lower (0.25 mg/liter) than those of the parental strain. After continuous stepwise exposure to CIP in vitro, six of eight TGC-susceptible isolates had reduced TGC susceptibility. Two of them acquired TGC resistance (TGC MIC, 4 mg/liter) and exhibited expression of acrA and acrB and mutations in acrR and/or marR. In conclusion, a population of fluoroquinolone-resistant E. coli isolates, including major extraintestinal pathogenic lineages O25b:H4-ST131-H30R and O1-ST648, showed reduced susceptibility to TGC due to overexpression of the efflux pump AcrAB-TolC, leading to decreased intracellular concentrations of the antibiotics that may be associated with the development of fluoroquinolone resistance.

scholarly journals Genomic and Functional Portrait of a Highly Virulent, CTX-M-15-ProducingH30-Rx Subclone of Escherichia coli Sequence Type 131

2015 ◽  
Vol 59 (10) ◽  
pp. 6087-6095 ◽  
Author(s):  
Amit Ranjan ◽  
Sabiha Shaik ◽  
Arif Hussain ◽  
Nishant Nandanwar ◽  
Torsten Semmler ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Genomic Analysis ◽  
Virulence Gene ◽  
Sequence Type ◽  
Fluoroquinolone Resistance ◽  
Comparative Genomic ◽  
Phylogenomic Analysis ◽  
Phenotypic Analysis ◽  
Content Type ◽  
E Coli

ABSTRACTEscherichia colisequence type 131 (ST131) is a pandemic clone associated with multidrug-resistant, extraintestinal infections, attributable to the presence of the CTX-M-15 extended-spectrum β-lactamase gene and mutations entailing fluoroquinolone resistance. Studies on subclones withinE. coliST131 are critically required for targeting and implementation of successful control efforts. Our study comprehensively analyzed the genomic and functional attributes of theH30-Rx subclonal strains NA097 and NA114, belonging to the ST131 lineage. We carried out whole-genome sequencing, comparative analysis, phenotypic virulence assays, and profiling of the antibacterial responses of THP1 cells infected with these subclones. Phylogenomic analysis suggested that the strains were clonal in nature and confined entirely to a single clade. Comparative genomic analysis revealed that the virulence and resistance repertoires were comparable among theH30-Rx ST131 strains except for the commensal ST131 strain SE15. Similarly, seven phage-specific regions were found to be strongly associated with theH30-Rx strains but were largely absent in the genome of SE15. Phenotypic analysis confirmed the virulence and resistance similarities between the two strains. However, NA097 was found to be more robust than NA114 in terms of virulence gene carriage (draoperon), invasion ability (P< 0.05), and antimicrobial resistance (streptomycin resistance). RT2gene expression profiling revealed generic upregulation of key proinflammatory responses in THP1 cells, irrespective of ST131 lineage status. In conclusion, our study provides comprehensive, genome-inferred insights into the biology and immunological properties of ST131 strains and suggests clonal diversification of genomic and phenotypic features within theH30-Rx subclone ofE. coliST131.

scholarly journals Antibiotic Selection of Escherichia coli Sequence Type 131 in a Mouse Intestinal Colonization Model

2014 ◽  
Vol 58 (10) ◽  
pp. 6139-6144 ◽  
Author(s):  
Frederik Boetius Hertz ◽  
Anders Løbner-Olesen ◽  
Niels Frimodt-Møller
Keyword(s):  
Escherichia Coli ◽  
Negative Impact ◽  
Sequence Type ◽  
Fluoroquinolone Resistance ◽  
Intestinal Colonization ◽  
Gram Positive ◽  
Gram Negative ◽  
Content Type ◽  
E Coli ◽  
Colonization Model

ABSTRACTThe ability of different antibiotics to select for extended-spectrum β-lactamase (ESBL)-producingEscherichia coliremains a topic of discussion. In a mouse intestinal colonization model, we evaluated the selective abilities of nine common antimicrobials (cefotaxime, cefuroxime, dicloxacillin, clindamycin, penicillin, ampicillin, meropenem, ciprofloxacin, and amdinocillin) against a CTX-M-15-producingE. colisequence type 131 (ST131) isolate with a fluoroquinolone resistance phenotype. Mice (8 per group) were orogastrically administered 0.25 ml saline with 108CFU/mlE. coliST131. On that same day, antibiotic treatment was initiated and given subcutaneously once a day for three consecutive days. CFU ofE. coliST131,Bacteroides, and Gram-positive aerobic bacteria in fecal samples were studied, with intervals, until day 8.Bacteroideswas used as an indicator organism for impact on the Gram-negative anaerobic population. For three antibiotics, prolonged colonization was investigated with additional fecal CFU counts determined on days 10 and 14 (cefotaxime, dicloxacillin, and clindamycin). Three antibiotics (cefotaxime, dicloxacillin, and clindamycin) promoted overgrowth ofE. coliST131 (P< 0.05). Of these, only clindamycin suppressedBacteroides, while the remaining two antibiotics had no negative impact onBacteroidesor Gram-positive organisms. Only clindamycin treatment resulted in prolonged colonization. The remaining six antibiotics, including ciprofloxacin, did not promote overgrowth ofE. coliST131 (P> 0.95), nor did they suppressBacteroidesor Gram-positive organisms. The results showed that antimicrobials both with and without an impact on Gram-negative anaerobes can select for ESBL-producingE. coli, indicating that not only Gram-negative anaerobes have a role in upholding colonization resistance. Other, so-far-unknown bacterial populations must be of importance for preventing colonization by incomingE. coli.

scholarly journals Complete Sequences ofmcr-1-Harboring Plasmids from Extended-Spectrum-β-Lactamase- and Carbapenemase-Producing Enterobacteriaceae

2016 ◽  
Vol 60 (7) ◽  
pp. 4351-4354 ◽  
Author(s):  
Aiqing Li ◽  
Yong Yang ◽  
Minhui Miao ◽  
Kalyan D. Chavda ◽  
José R. Mediavilla ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Klebsiella Pneumoniae ◽  
Sequence Type ◽  
Clinical Isolates ◽  
Incompatibility Group ◽  
Content Type ◽  
E Coli ◽  
Extended Spectrum ◽  
Complete Sequences ◽  
Group A

ABSTRACTHere we completely sequenced fourmcr-1-haboring plasmids, isolated from two extended-spectrum-β-lactamase (ESBL)-producingEscherichia coliand two carbapenemase-producingKlebsiella pneumoniaeclinical isolates. Themcr-1-harboring plasmids from anE. colisequence type 2448 (ST2448) isolate and twoK. pneumoniaeST25 isolates were identical (all pMCR1-IncX4), belonging to the IncX4 incompatibility group, while the plasmid from anE. coliST2085 isolate (pMCR1-IncI2) belongs to the IncI2 group. A nearly identical 2.6-kbmcr-1-pap2element was found to be shared by allmcr-1-carrying plasmids.

scholarly journals Molecular Epidemiological Analysis of Escherichia coli Sequence Type ST131 (O25:H4) andblaCTX-M-15among Extended-Spectrum-β-Lactamase-Producing E. coli from the United States, 2000 to 2009

2012 ◽  
Vol 56 (5) ◽  
pp. 2364-2370 ◽  
Author(s):  
James R. Johnson ◽  
Carl Urban ◽  
Scott J. Weissman ◽  
James H. Jorgensen ◽  
James S. Lewis ◽  
...  
Keyword(s):  
United States ◽  
Escherichia Coli ◽  
Antimicrobial Resistance ◽  
The United States ◽  
Sequence Type ◽  
Fluoroquinolone Resistance ◽  
Convenience Sample ◽  
Content Type ◽  
E Coli ◽  
Extended Spectrum

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.

scholarly journals Escherichia coli Sequence Type 131 H30 Is the Main Driver of Emerging Extended-Spectrum-β-Lactamase-Producing E. coli at a Tertiary Care Center

mSphere ◽  
2016 ◽  
Vol 1 (6) ◽  
Author(s):  
James R. Johnson ◽  
Brian Johnston ◽  
Paul Thuras ◽  
Bryn Launer ◽  
Evgeni V. Sokurenko ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Care Center ◽  
Tertiary Care ◽  
Sequence Type ◽  
Fluoroquinolone Resistance ◽  
Tertiary Care Center ◽  
Esbl Production ◽  
Content Type ◽  
E Coli ◽  
Extended Spectrum

ABSTRACT The ever-rising prevalence of resistance to first-line antibiotics among clinical Escherichia coli isolates leads to worse clinical outcomes and higher health care costs, thereby creating a need to discover its basis so that effective interventions can be developed. We found that the H30 subset within E. coli sequence type 131 (ST131-H30) is currently, and has been since at least 2004, the main E. coli lineage contributing to key resistance phenotypes—including extended-spectrum-beta-lactamase (ESBL) production, fluoroquinolone resistance, multidrug resistance, and dual ESBL production-plus-fluoroquinolone resistance—at a United States tertiary care center with a rising prevalence of ESBL-producing E. coli isolates. This identifies ST131-H30 as a target for diagnostic tests and preventive measures designed to curb the emergence of multidrug-resistant E. coli isolates and/or to blunt its clinical impact. The H30 strain of Escherichia coli sequence type 131 (ST131-H30) is a recently emerged, globally disseminated lineage associated with fluoroquinolone resistance and, via its H30Rx subclone, the CTX-M-15 extended-spectrum beta-lactamase (ESBL). Here, we studied the clonal background and resistance characteristics of 109 consecutive recent E. coli clinical isolates (2015) and 41 historical ESBL-producing E. coli blood isolates (2004 to 2011) from a public tertiary care center in California with a rising prevalence of ESBL-producing E. coli isolates. Among the 2015 isolates, ST131, which was represented mainly by ST131-H30, was the most common clonal lineage (23% overall). ST131-H30 accounted for 47% (8/17) of ESBL-producing, 47% (14/30) of fluoroquinolone-resistant, and 33% (11/33) of multidrug-resistant isolates. ST131-H30 also accounted for 53% (8/14) of dually fluoroquinolone-resistant, ESBL-producing isolates, with the remaining 47% comprised of diverse clonal groups that contributed a single isolate each. ST131-H30Rx, with CTX-M-15, was the major ESBL producer (6/8) among ST131-H30 isolates. ST131-H30 and H30Rx also dominated (46% and 37%, respectively) among the historical ESBL-producing isolates (2004 to 2011), without significant temporal shifts in relative prevalence. Thus, this medical center’s recently emerging ESBL-producing E. coli strains, although multiclonal, are dominated by ST131-H30 and H30Rx, which are the only clonally expanded fluoroquinolone-resistant, ESBL-producing lineages. Measures to rapidly and effectively detect, treat, and control these highly successful lineages are needed. IMPORTANCE The ever-rising prevalence of resistance to first-line antibiotics among clinical Escherichia coli isolates leads to worse clinical outcomes and higher health care costs, thereby creating a need to discover its basis so that effective interventions can be developed. We found that the H30 subset within E. coli sequence type 131 (ST131-H30) is currently, and has been since at least 2004, the main E. coli lineage contributing to key resistance phenotypes—including extended-spectrum-beta-lactamase (ESBL) production, fluoroquinolone resistance, multidrug resistance, and dual ESBL production-plus-fluoroquinolone resistance—at a United States tertiary care center with a rising prevalence of ESBL-producing E. coli isolates. This identifies ST131-H30 as a target for diagnostic tests and preventive measures designed to curb the emergence of multidrug-resistant E. coli isolates and/or to blunt its clinical impact.

Sign in / Sign up

Export Citation Format

Share Document