Characterization of tetracycline resistance genes in Escherichia coli isolated from feedlot cattle administered therapeutic or subtherapeutic levels of tetracycline

2013 ◽  
Vol 59 (4) ◽  
pp. 287-290 ◽  
Author(s):  
T.W. Alexander ◽  
X. Jin ◽  
Q. Li ◽  
S. Cook ◽  
T.A. McAllister

The effect of administering feedlot cattle subtherapeutic levels of chlortetracycline (CT) or CT and therapeutic levels of oxytetracycline (CT-OX) on resistance genotypes in Escherichia coli was investigated. Detection of genes tet(A), tet(B), and tet(C) encoded by tetracycline-resistant isolates (CT, N = 77; CT-OX, N = 99) was performed by multiplex polymerase chain reaction (PCR). Prevalence of tet(A) was similar in isolates across treatment regimes; however, prevalence of tet(B) was lower (18% versus 34%; P < 0.05) and tet(C) was higher (46% versus 28%; P < 0.05) in CT isolates compared with CT-OX isolates. To further characterize selection of resistance genotypes in E. coli, a group of intermediately tetracycline-resistant E. coli (N = 48) was analyzed. The tet(C) gene was present in 92% of these isolates. Copies of tet(C) transcripts, analyzed by real-time PCR, indicated that upregulation did not occur in tetracycline-resistant isolates when compared with intermediately resistant isolates. The minimum inhibitory concentrations of tetracycline, chlortetracycline, and oxytetracycline were also tested on isolates with different resistance genes. The minimum inhibitory concentration was dependent on the tetracycline analogue and the nature of encoded resistance. These data indicate that tetracycline analogues should not be used interchangeably to evaluate resistance and that prevalence of resistance genes in E. coli can vary according to the tetracycline analogue administered to cattle.

2015 ◽  
Vol 81 (16) ◽  
pp. 5560-5566 ◽  
Author(s):  
Seung Won Shin ◽  
Min Kyoung Shin ◽  
Myunghwan Jung ◽  
Kuastros Mekonnen Belaynehe ◽  
Han Sang Yoo

ABSTRACTThe aim of this study was to investigate the prevalence and transferability of resistance in tetracycline-resistantEscherichia coliisolates recovered from beef cattle in South Korea. A total of 155E. coliisolates were collected from feces in South Korea, and 146 were confirmed to be resistant to tetracycline. The tetracycline resistance genetet(A) (46.5%) was the most prevalent, followed bytet(B) (45.1%) andtet(C) (5.8%). Strains carryingtet(A) plustet(B) andtet(B) plustet(C) were detected in two isolates each. In terms of phylogenetic grouping, 101 (65.2%) isolates were classified as phylogenetic group B1, followed in decreasing order by D (17.4%), A (14.2%), and B2 (3.2%). Ninety-one (62.3%) isolates were determined to be multidrug resistant by the disk diffusion method. MIC testing using the principal tetracyclines, namely, tetracycline, chlortetracycline, oxytetracycline, doxycycline, and minocycline, revealed that isolates carryingtet(B) had higher MIC values than isolates carryingtet(A). Conjugation assays showed that 121 (82.9%) isolates could transfer a tetracycline resistance gene to a recipient via the IncFIB replicon (65.1%). This study suggests that the high prevalence of tetracycline-resistantE. coliisolates in beef cattle is due to the transferability of tetracycline resistance genes betweenE. colipopulations which have survived the selective pressure caused by the use of antimicrobial agents.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
R. V. Pereira ◽  
C. Foditsch ◽  
J. D. Siler ◽  
S. C. Dulièpre ◽  
C. Altier ◽  
...  

Abstract The objective of this study was to evaluate the longitudinal effect of enrofloxacin or tulathromycin use in calves at high risk of bovine respiratory disease (BRD) on antimicrobial resistance genes and mutation in quinolone resistance-determining regions (QRDR) in fecal E. coli. Calves at high risk of developing BRD were randomly enrolled in one of three groups receiving: (1) enrofloxacin (ENR; n = 22); (2) tulathromycin (TUL; n = 24); or (3) no treatment (CTL; n = 21). Fecal samples were collected at enrollment and at 7, 28, and 56 days after beginning treatment, cultured for Escherichiacoli (EC) and DNA extracted. Isolates were screened for cephalosporin, quinolone and tetracycline resistance genes using PCR. QRDR screening was conducted using Sanger sequencing. The only resistance genes detected were aac(6′)Ib-cr (n = 13), bla-CTX-M (n = 51), bla-TEM (n = 117), tetA (n = 142) and tetB (n = 101). A significantly higher detection of gyrA mutated at position 248 at time points 7 (OR = 11.5; P value = 0.03) and 28 (OR = 9.0; P value = 0.05) was observed in the ENR group when compared to calves in the control group. Our findings support a better understanding of the potential impacts from the use of enrofloxacin in calves on the selection and persistence of resistance.


2004 ◽  
Vol 70 (4) ◽  
pp. 2503-2507 ◽  
Author(s):  
Andrew Bryan ◽  
Nir Shapir ◽  
Michael J. Sadowsky

ABSTRACT Nonselected and natural populations of Escherichia coli from 12 animal sources and humans were examined for the presence and types of 14 tetracycline resistance determinants. Of 1,263 unique E. coli isolates from humans, pigs, chickens, turkeys, sheep, cows, goats, cats, dogs, horses, geese, ducks, and deer, 31% were highly resistant to tetracycline. More than 78, 47, and 41% of the E. coli isolates from pigs, chickens, and turkeys were resistant or highly resistant to tetracycline, respectively. Tetracycline MICs for 61, 29, and 29% of E. coli isolates from pig, chickens, and turkeys, respectively, were ≥233 μg/ml. Muliplex PCR analyses indicated that 97% of these strains contained at least 1 of 14 tetracycline resistance genes [tetA, tetB, tetC, tetD, tetE, tetG, tetK, tetL, tetM, tetO, tetS, tetA(P), tetQ, and tetX] examined. While the most common genes found in these isolates were tetB (63%) and tetA (35%), tetC, tetD, and tetM were also found. E. coli isolates from pigs and chickens were the only strains to have tetM. To our knowledge, this represents the first report of tetM in E. coli.


2017 ◽  
Vol 8 (2) ◽  
Author(s):  
Mamoona Amir ◽  
Muhammad Riaz ◽  
Yung-Fu Chang ◽  
Saeed Akhtar ◽  
Sang Ho Yoo ◽  
...  

Antibiotic resistance in Escherichia coli is a global health concern. We studied all possible routes of cross contamination of broiler meat with resistant E. coli from broiler feces at poultry shops. Various sample categories namely poultry feces, meat (n=225 for each), slaughterer hands, consumer hands, slaughterer knife, canister, tap water, carcass, feed and drinking water (n=50 for each) were collected from local poultry processing market. Samples were screened for prevalence of E. coli, resistance of isolates against ten antibiotics and presence of tetracycline- resistance genes in the isolates. Fecal samples had greatest colony count (4.1×104 CFU/g) as compared to meat (1.9×104 CFU/g) samples. Samples of consumer hands (6%) and tap water (12%) had less prevalence percentages of E. coli as compared to slaughterer hands (92%) and drinking water of broiler (86%). Isolates of eight sample categories had high resistant rate (≥90%) against oxytetracycline. On average, about 94% of the isolates from various sample categories possessed multidrug-resistance (MDR). Tetracycline-resistance genes (tetA and tetB) were identified in all sample categories except isolates of consumer hands and tap water. The distribution of tetracycline-resistance genes was significantly greater in fecal isolates (42%) than meat isolates (25%). The study depicted the spread of resistant E. coli in broiler meat through all studied routes of contamination of slaughtering periphery. This problem can be mitigated by strict monitoring of antibiotics use at poultry farms, prevention of cross contamination by adopting hygienic slaughter and vigorously screening the market meat for resistant E. coli.


Antibiotics ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 76 ◽  
Author(s):  
Nobuki Yoshizawa ◽  
Masaru Usui ◽  
Akira Fukuda ◽  
Tetsuo Asai ◽  
Hidetoshi Higuchi ◽  
...  

Manure compost has been thought of as a potential important route of transmission of antimicrobial-resistant bacteria (ARB) and antimicrobial resistance genes (ARGs) from livestock to humans. To clarify the abundance of ARB and ARGs, ARB and ARGs were quantitatively determined in tetracycline-resistant Escherichia coli (harboring the tetA gene)-spiked feces in simulated composts. In the simulated composts, the concentration of spiked E. coli decreased below the detection limit at day 7. The tetA gene remained in manure compost for 20 days, although the levels of the gene decreased. Next, to clarify the field conditions of manure compost in Japan, the quantities of tetracycline-resistant bacteria, tetracycline resistance genes, and residual tetracyclines were determined using field-manure-matured composts in livestock farms. Tetracycline-resistant bacteria were detected in 54.5% of tested matured compost (6/11 farms). The copy number of the tetA gene and the concentrations of residual tetracyclines in field manure compost were significantly correlated. These results suggest that the use of antimicrobials in livestock constitutes a selective pressure, not only in livestock feces but also in manure compost. The appropriate use of antimicrobials in livestock and treatment of manure compost are important for avoiding the spread of ARB and ARGs.


Author(s):  
Tanushree Barua Gupta ◽  
Malini Shariff ◽  
Thukral Ss ◽  
S.s Thukral

  Objective: Indiscriminate use of β-lactam antibiotics has resulted in the emergence of β-lactamase enzymes. AmpC β-lactamases, in particular, confer resistance to penicillin, first-, second-, and third-generation cephalosporins as well as monobactams and are responsible for antibiotic resistance in nosocomial pathogens. Therefore, this study was undertaken to screen nosocomial Escherichia coli isolates for the presence and characterization of AmpC β-lactamases. The study also envisaged on the detection of inducible AmpC β-lactamases and extended-spectrum β-lactamases (ESBLs) in AmpC β-lactamase-producing E. coli.Methods: A total of 102 clinical isolates of E. coli, were subjected to cefoxitin screening, and screen-positive isolates were further subjected to inhibitor-based detection method, phenotypic confirmatory test, disc antagonism test, polymerase chain reaction (PCR), and isoelectric focusing (IEF).Results: In this study, 33% of E. coli were resistant to cefoxitin, of which 35% were found to be positive for AmpC β-lactamase by inhibitor-based phenotypic test. Of the AmpC-positive isolates, 83% were positive for ESBLs, whereas 25% were producing inducible AmpC β-lactamases. PCR and IEF showed CIT and EBC types of AmpC β-lactamases present in the tested isolates.Conclusion: Our study showed the presence of inducible AmpC enzymes and ESBLs in E. coli isolates and PCR identified more isolates to be AmpC producers.


2020 ◽  
Vol 17 (3) ◽  
pp. 0710
Author(s):  
Md Fazlul Karim Khan ◽  
Shah Samiur Rashid

A significant increase in the incidence of non-O157 verotoxigenic Escherichia coli (VTEC) infections have become a serious health issues, and this situation is worsening due to the dissemination of plasmid mediated multidrug-resistant microorganisms worldwide. This study aims to investigate the presence of plasmid-mediated verotoxin gene in non-O157 E. coli. Standard microbiological techniques identified a total of 137 E. coli isolates. The plasmid was detected by Perfectprep Plasmid Mini preparation kit. These isolates were subjected to disk diffusion assay, and plasmid curing with ethidium bromide treatment. The plasmid containing isolates were subjected to a polymerase chain reaction (PCR) for investigating the presence of plasmid mediated verotoxin gene (VT1 and VT2) in non-O157 E. coli. Among the 137 E. coli isolates, 49 isolates were non-O157 E. coli while 29 (59.1%) isolates were verotoxin producing non-O157 serotypes and 26 non-O157 VTEC isolates possessed plasmids. Certain isolates harboured single sized plasmid while others had multiple plasmids with different size varied from 1.8kb to 7.6kb. A plasmid containing all (100%) the isolates was multidrug-resistant. Eight isolates changed their susceptibility patterns while three isolates were found to lose plasmid after post plasmid curing treatment and the rest of the isolates (15) remained constant. Different PCR sets characterized 3 plasmid-mediated verotoxins producing non-O157 E. coli. This current study demonstrated the occurrence of plasmid mediated verotoxin gene in non-O157 E. coli. To the best of our knowledge, this is the first report in the global literature on plasmid-mediated verotoxin gene in non-O157 E. coli. Timely diagnosis and surveillance of VTEC infections should prioritize to stop or slow down the virulence gene for dissemination by plasmid-mediated gene transfer amongst the same bacteria or other species.


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