scholarly journals Molecular epidemiology of Escherichia coli producing CTX-M and plasmid AmpC-type β-lactamases from dairy farms identifies a dominant plasmid encoding CTX-M-32 but no evidence for transmission to humans in the same geographical region

2019 ◽  
Author(s):  
Jacqueline Findlay ◽  
Oliver Mounsey ◽  
Winnie W.Y. Lee ◽  
Nerissa Newbold ◽  
Katy Morley ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Geographical Location ◽  
Dairy Farms ◽  
Generation Cephalosporin ◽  
Sequencing Analysis ◽  
Third Generation ◽  
E Coli ◽  
Animal Populations ◽  
Novel Variant ◽  
Close Relatives

AbstractThird-generation cephalosporin resistance (3GC-R) in Escherichia coli is a rising problem in human and farmed animal populations. We conducted whole genome sequencing analysis of 138 representative 3GC-R isolates previously collected from dairy farms in South West England and confirmed by PCR to carry acquired 3GC-R genes. This analysis identified blaCTX-M (131 isolates: encoding CTX-M-1, −14, −15, −32 and the novel variant, CTX-M-214), blaCMY-2 (6 isolates) and blaDHA-1 (one isolate). A highly conserved plasmid was identified in 73 isolates, representing 27 E. coli sequence types. This novel ~220 kb IncHI2 plasmid carrying blaCTX-M-32 was sequenced to closure and designated pMOO-32. It was found experimentally to be stable in cattle and human transconjugant E. coli even in the absence of selective pressure and was found by multiplex PCR to be present on 26 study farms representing a remarkable range of transmission over 1500 square kilometres. However, the plasmid was not found amongst human urinary E. coli we have recently characterised from people living in the same geographical location, collected in parallel with farm sampling. There were close relatives of two blaCTX-M plasmids circulating amongst eight human and two cattle isolates, and a closely related blaCMY-2 plasmid found in one cattle and one human isolate. However, phylogenetic evidence of recent sharing of 3GC-R strains between farms and humans in the same region was not found.ImportanceThird-generation cephalosporins (3GCs) are critically important antibacterials and 3GC-resistance (3GC-R) threatens human health, particularly in the context of opportunistic pathogens such as Escherichia coli. There is some evidence for zoonotic transmission of 3GC-R E. coli through food, but little work has been done examining possible transmission (e.g. via interaction of people with the local near-farm environment). We characterised acquired 3GC-R E. coli found on dairy farms in a geographically restricted region of the United Kingdom and compared these with E. coli from people living in the same region, collected in parallel. Whilst there is strong evidence for recent farm-to-farm transmission of 3GC-R strains and plasmids – including one epidemic plasmid that has a remarkable capacity to transmit – there was no evidence that 3GC-R found on study farms had a significant impact on circulating 3GC-R E. coli strains or plasmids in the local human population.

scholarly journals Molecular Epidemiology of Escherichia coli Producing CTX-M and pAmpC β-Lactamases from Dairy Farms Identifies a Dominant Plasmid Encoding CTX-M-32 but No Evidence for Transmission to Humans in the Same Geographical Region

2020 ◽  
Vol 87 (1) ◽  
Author(s):  
Jacqueline Findlay ◽  
Oliver Mounsey ◽  
Winnie W. Y. Lee ◽  
Nerissa Newbold ◽  
Katy Morley ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Geographical Location ◽  
Dairy Farms ◽  
Generation Cephalosporin ◽  
Sequencing Analysis ◽  
Third Generation ◽  
Content Type ◽  
E Coli ◽  
Animal Populations ◽  
Close Relatives

ABSTRACT Third-generation cephalosporin resistance (3GC-R) in Escherichia coli is a rising problem in human and farmed-animal populations. We conducted whole-genome sequencing analysis of 138 representative 3GC-R isolates previously collected from dairy farms in southwest England and confirmed by PCR to carry acquired 3GC-R genes. This analysis identified blaCTX-M (131 isolates encoding CTX-M-1, -14, -15, -and 32 and the novel variant CTX-M-214), blaCMY-2 (6 isolates), and blaDHA-1 (1 isolate). A highly conserved plasmid was identified in 73 isolates, representing 27 E. coli sequence types. This novel ∼220-kb IncHI2 plasmid carrying blaCTX-M-32 was sequenced to closure and designated pMOO-32. It was found experimentally to be stable in cattle and human transconjugant E. coli even in the absence of selective pressure and was found by multiplex PCR to be present on 26 study farms representing a remarkable range of transmission over 1,500 square kilometers. However, the plasmid was not found among human urinary E. coli isolates we recently characterized from people living in the same geographical location, collected in parallel with farm sampling. There were close relatives of two blaCTX-M plasmids circulating among eight human and two cattle isolates, and a closely related blaCMY-2 plasmid was found in one cattle and one human isolate. However, phylogenetic evidence of recent sharing of 3GC-R strains between farms and humans in the same region was not found. IMPORTANCE Third-generation cephalosporins (3GCs) are critically important antibacterials, and 3GC resistance (3GC-R) threatens human health, particularly in the context of opportunistic pathogens such as Escherichia coli. There is some evidence for zoonotic transmission of 3GC-R E. coli through food, but little work has been done examining possible transmission via interaction of people with the local near-farm environment. We characterized acquired 3GC-R E. coli found on dairy farms in a geographically restricted region of the United Kingdom and compared these with E. coli from people living in the same region, collected in parallel. While there is strong evidence for recent farm-to-farm transmission of 3GC-R strains and plasmids—including one epidemic plasmid that has a remarkable capacity to be transmitted—there was no evidence that 3GC-R E. coli found on study farms had a significant impact on circulating 3GC-R E. coli strains or plasmids in the local human population.

scholarly journals National Prevalence of Resistance to Third-Generation Cephalosporins in Escherichia coli Isolates from Layer Flocks in France

2013 ◽  
Vol 57 (12) ◽  
pp. 6351-6353 ◽  
Author(s):  
Claire Chauvin ◽  
Laetitia Le Devendec ◽  
Eric Jouy ◽  
Maena Le Cornec ◽  
Sylvie Francart ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Confidence Interval ◽  
Egg Production ◽  
Generation Cephalosporin ◽  
Gene Control ◽  
Third Generation ◽  
Content Type ◽  
E Coli ◽  
National Prevalence ◽  
Third Generation Cephalosporins

ABSTRACTResistance ofEscherichia colito third-generation cephalosporin (3GC) in fecal samples representative of French egg production was studied. The susceptibility to cefotaxime ofE. coliisolates obtained by culture on nonselective media was determined. Twenty-two nonsusceptible isolates were obtained (7.51%; 95% confidence interval, 4.49 to 10.54%), the majority of which came from young birds. Most isolates carried ablaCTX-M-1group gene, and a few carried ablaCMY-2-like gene. Control of 3GC resistance in laying hens is needed.

scholarly journals Clinical and Economic Impact of Third-Generation Cephalosporin-Resistant Infection or Colonization Caused by Escherichia coli and Klebsiella pneumoniae: A Multicenter Study in China

2020 ◽  
Vol 17 (24) ◽  
pp. 9285
Author(s):  
Xuemei Zhen ◽  
Cecilia Stålsby Lundborg ◽  
Xueshan Sun ◽  
Xiaoqian Hu ◽  
Hengjin Dong
Keyword(s):  
Escherichia Coli ◽  
Klebsiella Pneumoniae ◽  
Hospital Mortality ◽  
Multicenter Study ◽  
Generation Cephalosporin ◽  
Total Hospital Cost ◽  
Third Generation ◽  
E Coli ◽  
Significant Difference ◽  
The Impact

Quantifying economic and clinical outcomes for interventions could help to reduce third-generation cephalosporin resistance and Escherichia coli or Klebsiella pneumoniae. We aimed to compare the differences in clinical and economic burden between third-generation cephalosporin-resistant E. coli (3GCREC) and third-generation cephalosporin-susceptible E. coli (3GCSEC) cases, and between third-generation cephalosporin-resistant K. pneumoniae (3GCRKP) and third-generation cephalosporin-susceptible K. pneumoniae (3GCSKP) cases. A retrospective and multicenter study was conducted. We collected data from electronic medical records for patients who had clinical samples positive for E. coli or K. pneumoniae isolates during 2013 and 2015. Propensity score matching (PSM) was conducted to minimize the impact of potential confounding variables, including age, sex, insurance, number of diagnoses, Charlson comorbidity index, admission to intensive care unit, surgery, and comorbidities. We also repeated the PSM including length of stay (LOS) before culture. The main indicators included economic costs, LOS and hospital mortality. The proportions of 3GCREC and 3GCRKP in the sampled hospitals were 44.3% and 32.5%, respectively. In the two PSM methods, 1804 pairs and 1521 pairs were generated, and 1815 pairs and 1617 pairs were obtained, respectively. Compared with susceptible cases, those with 3GCREC and 3GCRKP were associated with significantly increased total hospital cost and excess LOS. Inpatients with 3GCRKP were significantly associated with higher hospital mortality compared with 3GCSKP cases, however, there was no significant difference between 3GCREC and 3GCSEC cases. Cost reduction and outcome improvement could be achieved through a preventative approach in terms of both antimicrobial stewardship and preventing the transmission of organisms.

scholarly journals Fluoroquinolone-Resistant Escherichia coli Originating on Dairy Farms are an Infrequent Cause of Bacteriuria in Humans Living in the Same Geographical Region

2021 ◽  
Author(s):  
Oliver Mounsey ◽  
Hannah Schubert ◽  
Jacqueline Findlay ◽  
Katy Morley ◽  
Emma F. Puddy ◽  
...  
Keyword(s):  
Risk Factors ◽  
Escherichia Coli ◽  
Positive Association ◽  
Dairy Farms ◽  
Generation Cephalosporin ◽  
Geographical Region ◽  
E Coli ◽  
Dry Cow Therapy ◽  
On Farm ◽  
South West England

SynopsisBackgroundOur primary aim was to test whether cattle-associated fluoroquinolone-resistant (FQ-R) Escherichia coli found on dairy farms were a significant cause of bacteriuria in humans living in the same 50 x 50 km geographical region located in South West England. Another aim was to identify risk factors for the presence of FQ-R E. coli on dairy farms.MethodsFQ-R E. coli were isolated during 2017-18 from 42 dairy farms and from community urine samples. Forty-two cattle and 489 human urinary isolates were subjected to WGS, allowing phylogenetic comparisons. Risk factors were identified using a Bayesian regularisation approach.ResultsOf 489 FQ-R human isolates, 255 were also 3rd generation cephalosporin-resistant (3GC-R), with strong genetic linkage between aac(6’)Ib-cr and blaCTX-M-15. We identified possible farm-to-human sharing for pairs of ST744 and ST162 isolates, but core genome SNP distances (71 and 63, respectively) were smaller in pairs of ST744 and ST162 isolates from different farms (7 and 3 SNPs, respectively). Total farm fluoroquinolone use showed a positive association with the odds of isolating FQ-R E. coli while total dry cow therapy use showed a negative association.ConclusionsThis work suggests that FQ-R E. coli found on dairy farms have a limited impact on community bacteriuria within the local human population, however, this appears greater than observed for 3GC-R E. coli when studied in parallel. Reducing fluoroquinolone use may reduce the on-farm prevalence of FQ-R E. coli, and this reduction may be greater when dry cow therapy is targeted to the ecology of resistant E. coli on the farm.

Intrathecal Administration of Amikacin for Treatment of Meningitis Secondary to Cephalosporin-Resistant Escherichia Coli

1993 ◽  
Vol 27 (7-8) ◽  
pp. 870-873 ◽  
Author(s):  
Sandra L. Preston ◽  
Laurie L. Briceland
Keyword(s):  
Escherichia Coli ◽  
Bacterial Resistance ◽  
Generation Cephalosporin ◽  
Intrathecal Administration ◽  
Neurosurgical Procedures ◽  
Third Generation ◽  
E Coli ◽  
Efficacious Treatment ◽  
Clonic Seizures ◽  
Third Generation Cephalosporins

OBJECTIVE: To report a case of gram-negative bacillary meningitis (GNBM) secondary to cephalosporin-resistant Escherichia coli that was treated with intrathecal and intravenous amikacin and intravenous imipenem/cilastatin (I/C). CASE SUMMARY: A patient who had undergone two recent neurosurgical procedures developed GNBM and bacteremia. He was treated empirically with ceftazidime. Both bloodstream and cerebrospinal fluid isolates were identified as E. coli, resistant to third-generation cephalosporins, penicillins, tobramycin, and gentamicin. The patient was subsequently treated with intravenous and intrathecal amikacin plus intravenous I/C He experienced subjective and objective improvement on days 2–4 of antimicrobial therapy; two generalized tonic-clonic seizures occurred on days 7 and 12. Intrathecal amikacin was discontinued after 6 days, and intravenous amikacin and I/C were discontinued after 23 and 27 days, respectively. The patient's mental status did not completely return to premeningitis baseline. DISCUSSION: Third-generation cephalosporins are the treatment of choice for GNBM. In the case reported herein, bacterial resistance to these agents prompted the use of a therapy that has not been well studied and is also considered to be less safe and perhaps less efficacious. Treatment of GNBM with an intrathecally administered aminoglycoside or with intravenous I/C plus an aminoglycoside is reviewed. CONCLUSIONS: Patients with GNBM secondary to third-generation cephalosporin-resistant organisms may require therapies that may be less effective and more toxic. Further study of alternative agents is warranted.

scholarly journals Characterization of AmpC-hyperproducing Escherichia coli from humans and dairy farms collected in parallel in the same geographical region

2020 ◽  
Vol 75 (9) ◽  
pp. 2471-2479 ◽  
Author(s):  
Maryam Alzayn ◽  
Jacqueline Findlay ◽  
Hannah Schubert ◽  
Oliver Mounsey ◽  
Virginia C Gould ◽  
...  
Keyword(s):  
Risk Factors ◽  
Phylogenetic Analysis ◽  
Human Population ◽  
Dairy Farms ◽  
Generation Cephalosporin ◽  
Third Generation ◽  
E Coli ◽  
Increased Risk ◽  
Amoxicillin Clavulanate ◽  
Cephalosporin Resistance

Abstract Objectives To characterize putative AmpC-hyperproducing third-generation cephalosporin-resistant E. coli from dairy farms and their phylogenetic relationships; to identify risk factors for their presence; and to assess evidence for their zoonotic transmission into the local human population. Methods Proteomics was used to explain differences in antimicrobial susceptibility. WGS allowed phylogenetic analysis. Multilevel, multivariable logistic regression modelling was used to identify risk factors. Results Increased use of amoxicillin/clavulanate was associated with an increased risk of finding AmpC hyperproducers on farms. Expansion of cephalosporin resistance in AmpC hyperproducers was seen in farm isolates with marR mutations (conferring cefoperazone resistance) or when AmpC was mutated (conferring fourth-generation cephalosporin and cefoperazone resistance). Phylogenetic analysis confirmed the dominance of ST88 amongst farm AmpC hyperproducers but there was no evidence for acquisition of farm isolates by members of the local human population. Conclusions Clear evidence was found for recent farm-to-farm transmission of AmpC-hyperproducing E. coli and of adaptive mutations to expand resistance. Whilst there was no evidence of isolates entering the local human population, efforts to reduce third-generation cephalosporin resistance on dairy farms must address the high prevalence of AmpC hyperproducers. The finding that amoxicillin/clavulanate use was associated with an increased risk of finding AmpC hyperproducers is important because this is not currently categorized as a highest-priority critically important antimicrobial and so is not currently targeted for specific usage restrictions in the UK.

scholarly journals Role of Ceftiofur in Selection and Dissemination of blaCMY-2-Mediated Cephalosporin Resistance in Salmonella enterica and Commensal Escherichia coli Isolates from Cattle

2009 ◽  
Vol 75 (11) ◽  
pp. 3648-3655 ◽  
Author(s):  
Joshua B. Daniels ◽  
Douglas R. Call ◽  
Dale Hancock ◽  
William M. Sischo ◽  
Katherine Baker ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
The United States ◽  
Generation Cephalosporin ◽  
Plasmid Transfer ◽  
Third Generation ◽  
Antimicrobial Drugs ◽  
E Coli ◽  
History Of ◽  
Cephalosporin Resistance

ABSTRACT Third-generation cephalosporin resistance of Salmonella and commensal Escherichia coli isolates from cattle in the United States is predominantly conferred by the cephamycinase CMY-2, which inactivates β-lactam antimicrobial drugs used to treat a wide variety of infections, including pediatric salmonellosis. The emergence and dissemination of bla CMY-2 --bearing plasmids followed and may in part be the result of selection pressure imposed by the widespread utilization of ceftiofur, a third-generation veterinary cephalosporin. This study assessed the potential effects of ceftiofur on bla CMY-2 transfer and dissemination by (i) an in vivo experimental study in which calves were inoculated with competent bla CMY-2-bearing plasmid donors and susceptible recipients and then subjected to ceftiofur selection and (ii) an observational study to determine whether ceftiofur use in dairy herds is associated with the occurrence and frequency of cephalosporin resistance in Salmonella and commensal E. coli. The first study revealed bla CMY-2 plasmid transfer in both ceftiofur-treated and untreated calves but detected no enhancement of plasmid transfer associated with ceftiofur treatment. The second study detected no association (P = 0.22) between ceftiofur use and either the occurrence of ceftiofur-resistant salmonellosis or the frequency of cephalosporin resistance in commensal E. coli. However, herds with a history of salmonellosis (including both ceftiofur-resistant and ceftiofur-susceptible Salmonella isolates) used more ceftiofur than herds with no history of salmonellosis (P = 0.03) These findings fail to support a major role for ceftiofur use in the maintenance and dissemination of bla CMY-2-bearing plasmid mediated cephalosporin resistance in commensal E. coli and in pathogenic Salmonella in these dairy cattle populations.

scholarly journals 646. Adapting the modified Carbapenem Inactivation Method to assess for possible beta-lactamase mediated resistance in Piperacillin-Tazobactam resistant/ Ceftriaxone susceptible Escherichia. coli and Klebsiella pneumoniae

2020 ◽  
Vol 7 (Supplement_1) ◽  
pp. S382-S382
Author(s):  
Alexander Lawandi ◽  
Samuel De L’Etoile-Morel ◽  
Gleice C Leite ◽  
Todd C Lee
Keyword(s):  
Escherichia Coli ◽  
Carbapenem Resistance ◽  
Generation Cephalosporin ◽  
Third Generation ◽  
Beta Lactamase ◽  
Review Of The Literature ◽  
Beta Lactamases ◽  
Resistance Phenotype ◽  
E Coli ◽  
Reference Strains

Abstract Background A cluster of piperacillin-tazobactam resistant/ceftriaxone susceptible Escherichia coli and Klebsiella pneumonaie bacteremias were noted at our institution. A review of the literature suggested this resistance phenotype was mediated by a beta-lactamase. We sought to further corroborate this phenotypically. Methods We adapted the “carbapenem inactivation method” utilizing piperacillin-tazobactam and ceftriaxone discs on all E. coli and K. pneumoniae isolated from blood and demonstrating piperacillin-tazobactam resistance but with ceftriaxone susceptibility. We utilized pan-susceptible and carbapenem resistance Enterobacteriaceae reference strains as well as third generation cephalosporin resistant, piperacillin-tazobactam susceptible isolates as controls. Results 96% of the piperacillin-tazobactam resistant, ceftriaxone susceptible strains demonstrated the capacity to degrade the piperacillin-tazobactam discs while 100% spared the ceftriaxone discs. 75% of the piperacillin-tazobactam susceptible, ceftriaxone resistant control strains spared the piperacillin-tazobactam discs while degrading the ceftriaxone discs. Conclusion The resistance phenotype observed is due to beta-lactamase production and the modified carbapenem inactivation method can be adapted to probe for other beta-lactamases. Further study is required to definitively identify which beta-lactamase is responsible. Disclosures All Authors: No reported disclosures

scholarly journals Increasing incidence and antimicrobial resistance in Escherichia coli bloodstream infections: a multinational population-based cohort study

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Melissa C. MacKinnon ◽  
Scott A. McEwen ◽  
David L. Pearl ◽  
Outi Lyytikäinen ◽  
Gunnar Jacobsson ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Incidence Rate ◽  
Bloodstream Infections ◽  
Generation Cephalosporin ◽  
Population Based ◽  
Incidence Rates ◽  
Third Generation ◽  
Common Cause ◽  
E Coli ◽  
Cephalosporin Resistance

Abstract Background Escherichia coli is an important pathogen in humans and is the most common cause of bacterial bloodstream infections (BSIs). The objectives of our study were to determine factors associated with E. coli BSI incidence rate and third-generation cephalosporin resistance in a multinational population-based cohort. Methods We included all incident E. coli BSIs (2014–2018) from national (Finland) and regional (Australia [Canberra], Sweden [Skaraborg], and Canada [Calgary, Sherbrooke, and western interior]) surveillance. Incidence rates were directly age and sex standardized to the European Union 28-country 2018 population. Multivariable negative binomial and logistic regression models estimated factors significantly associated with E. coli BSI incidence rate and third-generation cephalosporin resistance, respectively. The explanatory variables considered for inclusion in both models were year (2014–2018), region (six areas), age (< 70-years-old and ≥ 70-years-old), and sex (female and male). Results We identified 31,889 E. coli BSIs from 40.7 million person-years of surveillance. Overall and third-generation cephalosporin-resistant standardized rates were 87.1 and 6.6 cases/100,000 person-years, respectively, and increased 14.0% and 40.1% over the five-year study. Overall, 7.8% (2483/31889) of E. coli BSIs were third-generation cephalosporin-resistant. Calgary, Canberra, Sherbrooke, and western interior had significantly lower E. coli BSI rates compared to Finland. The significant association between age and E. coli BSI rate varied with sex. Calgary, Canberra, and western interior had significantly greater odds of third-generation cephalosporin-resistant E. coli BSIs compared to Finland. Compared to 2014, the odds of third-generation cephalosporin-resistant E. coli BSIs were significantly increased in 2016, 2017, and 2018. The significant association between age and the odds of having a third-generation cephalosporin-resistant E. coli BSI varied with sex. Conclusions Increases in overall and third-generation cephalosporin-resistant standardized E. coli BSI rates were clinically important. Overall, E. coli BSI incidence rates were 40–104% greater than previous investigations from the same study areas. Region, sex, and age are important variables when analyzing E. coli BSI rates and third-generation cephalosporin resistance in E. coli BSIs. Considering E. coli is the most common cause of BSIs, this increasing burden and evolving third-generation cephalosporin resistance will have an important impact on human health, especially in aging populations.

scholarly journals Antibiotic resistance among Escherichia coli and Salmonella isolated from dairy cattle feces in Texas

2020 ◽  
Author(s):  
Rosine Manishimwe ◽  
Paola M. Moncada ◽  
Marie Bugarel ◽  
H. Morgan Scott ◽  
Guy H. Loneragan
Keyword(s):  
Escherichia Coli ◽  
Antibiotic Resistance ◽  
Dairy Cattle ◽  
Nalidixic Acid ◽  
Generation Cephalosporin ◽  
Third Generation ◽  
Bacterial Isolates ◽  
Macconkey Agar ◽  
E Coli ◽  
Cattle Feces

AbstractThis study was conducted to develop and field-test a low cost protocol to estimate the isolate- and sample-level prevalence of resistance to critically important antibiotic drugs among Escherichia coli and Salmonella isolated from dairy cattle feces. E. coli and Salmonella were isolated from and screened on selective media, with and without antibiotics respectively. Bacterial isolates were further tested for susceptibility to a suite of antibiotics using disk diffusion. Molecular methods were performed on select bacterial isolates to identify and distinguish genetic determinants associated with the observed phenotypes. Among 85 non-type-specific E. coli randomly isolated from MacConkey agar without antibiotics, the isolate-level prevalence of resistance to tetracycline was the highest (8.2%), there was no isolate resistant to third-generation cephalosporin (0.0%) and one isolate was resistant to nalidixic acid (1.2%). Among 37 E. coli recovered from MacConkey agar with cefotaxime at 1.0µg/ml, 100% were resistant to ampicillin and 56.8% were resistant to a third-generation cephalosporin (ceftriaxone). Among 22 E. coli isolates recovered from MacConkey agar with ciprofloxacin at 0.5µg/ml, 90.9% were resistant to tetracycline whereas 77.3% and 54.5% were resistant to nalidixic acid and ciprofloxacin respectively. Sixteen Salmonella were isolated and only one demonstrated any resistance (i.e., single resistance to streptomycin). Among E. coli isolates that were either resistant or intermediate to ceftriaxone, an AmpC phenotype was more common than an extended spectrum beta-lactamase (ESBL) phenotype (29 versus 10 isolates, respectively). Among 24 E. coli isolates that were whole genome sequenced, phenotypic profiles of antibiotic resistance detected were generally substantiated by genotypic profiles. For instance, all isolates with an AmpC phenotype carried a blaCMY2 gene. The protocol used in this study is suited to detecting and estimating prevalence of antimicrobial resistance in bacteria isolated from food animal feces in resource-limited laboratories in the developing world.

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