scholarly journals Transfer of Class 1 Integron-Mediated Antibiotic Resistance Genes from Shiga Toxin-Producing Escherichia coli to a Susceptible E. coli K-12 Strain in Storm Water and Bovine Feces

2008 ◽  
Vol 74 (16) ◽  
pp. 5063-5067 ◽  
Author(s):  
Supakana Nagachinta ◽  
Jinru Chen

ABSTRACT Transfer of class 1 integron-mediated antibiotic resistance genes has been demonstrated under laboratory conditions. However, there is no information concerning the transfer of these genes in an agricultural environment. The present study sought to determine if integron-mediated streptomycin and sulfisoxazole resistance genes could be transferred from Shiga toxin-producing Escherichia coli (STEC) strains 6-20 (O157:H7) and 7-63 (O111:H8) to the susceptible strain E. coli K-12 MG1655 in bovine feces (pH 5.5, 6.0, or 6.5) and storm water (pH 5, 6, 7, or 8) at 4, 15, and 28°C, which are average seasonal temperatures for winter, spring-fall, and summer, respectively, in the Griffin, GA, area. The results indicated that at 28°C, the integron-mediated antibiotic resistance genes were transferred from both of the STEC donors in bovine feces. Higher conjugation efficiencies were, however, observed in the conjugation experiments involving STEC strain 6-20. In storm water, the resistance genes were transferred only from STEC strain 6-20. Greater numbers of transconjugants were recovered in the conjugation experiments performed with pH 6.5 bovine feces and with pH 7 storm water. Antibiotic susceptibility tests confirmed the transfer of integron-mediated streptomycin resistance and sulfisoxazole resistance, as well as the transfer of non-integron-mediated oxytetracycline resistance and tetracycline resistance in the transconjugant cells. These results suggest that the antibiotic resistance genes in STEC could serve as a source of antibiotic resistance genes disseminated via conjugation to susceptible cells of other E. coli strains in an agricultural environment.

2009 ◽  
Vol 72 (1) ◽  
pp. 21-27 ◽  
Author(s):  
SUPAKANA NAGACHINTA ◽  
JINRU CHEN

This study was undertaken to characterize the integrons present in a group of Shiga toxin–producing Escherichia coli (STEC) isolates and the ability of these integrons to transfer antibiotic resistance genes from STEC to E. coli K-12 MG1655. A total of 177 STEC isolates were analyzed for antibiotic susceptibility and the presence of integrons. Class 1 integrons were detected in 14 STEC isolates, and a class 2 integron was identified in 1 STEC isolate. The STEC isolates positive for class 1 integrons were resistant to streptomycin (MICs > 128 μg/ml) and sulfisoxazole (MICs > 1,024 μg/ml), and the isolate positive for the class 2 integron was resistant to streptomycin (MIC of 128 μg/ml), trimethoprim (MIC > 256 μg/ml), and streptothricin (MIC > 32 μg/ml). Results of restriction digestion and nucleotide sequencing revealed that the cassette regions of the class 1 integrons had a uniform size of 1.1 kb and contained a nucleotide sequence identical to that of aadA1. The class 2 integron cassette region was 2.0 kb and carried nucleotide sequences homologous to those of aadA1, sat1, and dfrA1. Results of the conjugation experiments revealed that horizontal transfers of conjugative plasmids are responsible for the dissemination of class 1 integron–mediated antibiotic resistance genes from STEC to E. coli K-12 MG1655. Antibiotic resistance traits not mediated by integrons, such as resistance to tetracycline and oxytetracycline, were cotransferred with the integron-mediated antibiotic resistance genes. The study suggested a possible role of integron and conjugative plasmid in dissemination of genes conferring resistance to antibiotics from pathogenic to generic E. coli cells.


2004 ◽  
Vol 48 (10) ◽  
pp. 3996-4001 ◽  
Author(s):  
Yolanda Sáenz ◽  
Laura Briñas ◽  
Elena Domínguez ◽  
Joaquim Ruiz ◽  
Myriam Zarazaga ◽  
...  

ABSTRACT Seventeen multiple-antibiotic-resistant nonpathogenic Escherichia coli strains of human, animal, and food origins showed a wide variety of antibiotic resistance genes, many of them carried by class 1 and class 2 integrons. Amino acid changes in MarR and mutations in marO were identified for 15 and 14 E. coli strains, respectively.


2017 ◽  
Vol 62 (No. 3) ◽  
pp. 169-177 ◽  
Author(s):  
TH Chung ◽  
SW Yi ◽  
BS Kim ◽  
WI Kim ◽  
GW Shin

The present study sought to identify pathogens associated with septicaemia in the Chinese soft-shelled turtle (Pelodiscus sinensis) and to characterise antibiotic resistance in these pathogens. Twenty-three isolates recovered from the livers of diseased soft-shelled turtles were genetically identified as Aeromonas hydrophila (n = 8), A. veronii (n = 3), Citrobacter freundii (n = 4), Morganella morganii (n = 3), Edwardsiella tarda (n = 2), Wohlfahrtiimonas chitiniclastica (n = 1), Chryseobacterium sp. (n = 1), and Comamonas sp. (n = 1). Most isolates (n = 21) were resistant to ampicillin whereas a low percentage of isolates was susceptible to aminoglycosides (amikacin, gentamicin, and tobramycin). PCR assays and sequence analysis revealed the presence of the qnrS2 and bla<sub>TEM</sub> antibiotic resistance genes in all isolates. The bla<sub>DHA-1</sub>, bla<sub>CTX-M-14</sub> and bla<sub>CMY-2</sub> genes were harboured by 17.4% (n = 4), 13.5% (n = 3) and 8.7% (n = 2) of the strains, respectively. One or more tetracycline resistance genes were detected in 60.9% (n = 14) of the isolates. Four isolates (17.4%) harboured single or multiple class 1 integron cassettes. Collectively, a variety of bacterial pathogens were involved in the occurrence of septicaemia in Chinese soft-shelled turtles and most of the isolates had multi-antibiotic resistant phenotypes. To our knowledge, the present report is the first to identify W. chitiniclastica and Comamonas sp. as causes of septicaemia in soft-shelled turtles and the first to identify Aeromonas spp. with bla<sub>CTX-M-14</sub> and bla<sub>DHA-1</sub> resistance genes.


Water ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 450 ◽  
Author(s):  
Ocean Thakali ◽  
Sarmila Tandukar ◽  
John Brooks ◽  
Samendra Sherchan ◽  
Jeevan Sherchand ◽  
...  

Urban rivers affected by anthropogenic activities can act as reservoirs of antibiotic resistance genes (ARGs). This study aimed to describe the occurrence of selected ARGs (blaTEM, ermF, mecA, and tetA) and a class 1 integron (intI1) in an urban river in Nepal. A total of 18 water samples were collected periodically from upstream, midstream, and downstream sites along the Bagmati River over a 1-year period. All ARGs except mecA and intI1 were consistently detected by a quantitative polymerase chain reaction in the midstream and downstream sites, with concentrations ranging from 3.1 to 7.8 log copies/mL. ARG abundance was significantly lower at the upstream site (p < 0.05), reflecting the impact of anthropogenic activities on increasing concentrations of ARGs at midstream and downstream sites. Our findings demonstrate the presence of clinically relevant ARGs in the urban river water of Nepal, suggesting a need for mitigating strategies to prevent the spread of antibiotic resistance in the environment.


2020 ◽  
Vol 11 ◽  
Author(s):  
Masaki Shintani ◽  
Eman Nour ◽  
Tarek Elsayed ◽  
Khald Blau ◽  
Inessa Wall ◽  
...  

IncP-1 plasmids, first isolated from clinical specimens (R751, RP4), are recognized as important vectors spreading antibiotic resistance genes. The abundance of IncP-1 plasmids in the environment, previously reported, suggested a correlation with anthropogenic pollution. Unexpectedly, qPCR-based detection of IncP-1 plasmids revealed also an increased relative abundance of IncP-1 plasmids in total community DNA from the rhizosphere of lettuce and tomato plants grown in non-polluted soil along with plant age. Here we report the successful isolation of IncP-1 plasmids by exploiting their ability to mobilize plasmid pSM1890. IncP-1 plasmids were captured from the rhizosphere but not from bulk soil, and a high diversity was revealed by sequencing 14 different plasmids that were assigned to IncP-1β, δ, and ε subgroups. Although backbone genes were highly conserved and mobile elements or remnants as Tn501, IS1071, Tn402, or class 1 integron were carried by 13 of the sequenced IncP-1 plasmids, no antibiotic resistance genes were found. Instead, seven plasmids had a mer operon with Tn501-like transposon and five plasmids contained putative metabolic gene clusters linked to these mobile elements. In-depth sequence comparisons with previously known plasmids indicate that the IncP-1 plasmids captured from the rhizosphere are archetypes of those found in clinical isolates. Our findings that IncP-1 plasmids do not always carry accessory genes in unpolluted rhizospheres are important to understand the ecology and role of the IncP-1 plasmids in the natural environment.


2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Jianhua Qiu ◽  
Zhiyu Jiang ◽  
Zijing Ju ◽  
Xiaonan Zhao ◽  
Jie Yang ◽  
...  

In this study, the prevalence, phenotypes, and clonal relationships ofEscherichia coli(E. coli) strains isolated from minks were investigated. In July 2017, a total of 62 fresh faecal swab samples were randomly collected from one large-scale mink farm in Zhucheng, Shandong Province, China. In all the samples, 50E. colistrains were isolated and then assigned to serotyping, antimicrobial susceptibility test, detection of antimicrobial resistance genes and the Class 1 integrons, and multilocus sequence typing (MLST). Four pathogenic serotypes were identified among all the isolates, while the most common serotype was enterohemorrhagicE. coliO104:H4 (6.0 %). Antimicrobial sensitivity testing revealed that most isolates were susceptible to cefoxitin (96.0 %) and amikacin (82.0 %), while most isolates were resistant to ampicillin (92.0 %) and tetracycline (90.0 %). An analysis of the nucleotide sequences revealed that 7 isolates (14.0%) carried 4 types of Class 1 integron cassette, includingdfrA27+aadA2+qnrA(57.1%),dfrA17+aadA5(14.3%),dfrA12+aadA2(14.3%), anddfrA1+aadA1(14.3%). PCR screening showed that 14 antibiotic resistance genes were presented in 50 isolates, while the most prevalent resistance gene wasqnrS, which was detected in 60.0 % of isolates, followed bysul2(40.0%) andoqxA(38.0%). MLST analysis showed that 32 sequence types (STs) were identified, while ST46 was the predominant genotype among all isolates. Clonal complex 3 (CC3) was dominant. Compared with 340 humanE. coliSTs reported in China, the ST10 clonal complex, known as the largest human clonal complex, was also found in the 50 minkE. coliisolates. Meanwhile, mink-derived strain ST206 formed a new clonal complex, CC206, which was different from human ST strains. Our results showed that farmed minks could be reservoirs of antimicrobial-resistantE. coliwith Class 1 integron cassettes and resistance genes, which were likely to pose a threat to public health. Therefore, continuous inspections and monitoring ofE. coliin minks are essential for detecting and controlling emergingE. coliwith different serovars as well as antibiotic resistance.


2012 ◽  
Vol 2012 ◽  
pp. 1-13 ◽  
Author(s):  
Hassan Momtaz ◽  
Rahil Farzan ◽  
Ebrahim Rahimi ◽  
Farhad Safarpoor Dehkordi ◽  
Negar Souod

The aims of the current study were to detect the virulence factors and antibiotic resistance of Shiga toxin-producingE. coli, in animal milk and dairy products in Iran. AfterE. colidentification with culture method, PCR assay were developed for detection of pathogenic genes, serotypes and antibiotic resistance genes ofE. coli. Results showed that out of 719 samples, 102 (14.18%) were confirmed to be positive forE. coliand out of 102 positive samples, 17.64% were O26 and 13.72% were O157 and 1.96% were O91 and 1.96% were O145 serotypes. Totally, the prevalence ofstx1 andpapAgenes were the highest while the prevalence ofsfaSandfyuAwere the lowest in the positive samples. PCR results showed thattetA, tetBwere the highest (64.70%) andaac(3)-IVwere the lowest (27.45%) antibiotic resistant genes inE. colipositive samples. Our study indicated that the isolatedE. colitrains in these regions had a highest antibiotic resistance to tetracycline (58.82%) and the lowest to nitrofurantoin (3.92%).tetAgene andE. coliO157 serotype had highest andaac(3)-IVgene, andE. coliO145 serotype had a lowest frequency rates of antibiotics resistance genes, in the region.


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