# | Rank | Similarity | Title + Abs. | Year | PMID |
|---|---|---|---|---|---|
| 0 | 1 | 2 | 3 | 4 | 5 |
| 3556 | 0 | 1.0000 | Antimicrobial resistance genes in marine bacteria and human uropathogenic Escherichia coli from a region of intensive aquaculture. Antimicrobials are heavily used in Chilean salmon aquaculture. We previously found significant differences in antimicrobial-resistant bacteria between sediments from an aquaculture and a non-aquaculture site. We now show that levels of antimicrobial resistance genes (ARG) are significantly higher in antimicrobial-selected marine bacteria than in unselected bacteria from these sites. While ARG in tetracycline- and florfenicol-selected bacteria from aquaculture and non-aquaculture sites were equally frequent, there were significantly more plasmid-mediated quinolone resistance genes per bacterium and significantly higher numbers of qnrB genes in quinolone-selected bacteria from the aquaculture site. Quinolone-resistant urinary Escherichia coli from patients in the Chilean aquacultural region were significantly enriched for qnrB (including a novel qnrB gene), qnrS, qnrA and aac(6')-1b, compared with isolates from New York City. Sequences of qnrA1, qnrB1 and qnrS1 in quinolone-resistant Chilean E. coli and Chilean marine bacteria were identical, suggesting horizontal gene transfer between antimicrobial-resistant marine bacteria and human pathogens. | 2015 | 26259681 |
| 3557 | 1 | 0.9999 | Characterization of the variable region in the class 1 integron of antimicrobial-resistant Escherichia coli isolated from surface water. Fecal bacteria are considered to be a potential reservoir of antimicrobial resistance genes in the aquatic environment and could horizontally transfer these genes to autochthonous bacteria when carried on transferable and/or mobile genetic elements. Such circulation of resistance genes constitutes a latent public health hazard. The aim of this study was to characterize the variable region of the class 1 integron and relate its genetic content to resistance patterns observed in antimicrobial-resistant Escherichia coli isolated from the surface waters of Patos Lagoon, Southern Brazil. Genetic diversity of the isolates and presence of the qacEΔ1 gene, which confers resistance to quaternary ammonium compounds, were also investigated. A total of 27 isolates were analyzed. The variable region harbored dfrA17, dfrA1 and dfrA12 genes, which confer resistance to trimethoprim, and aadA1, aadA5 and aadA22 genes that encode resistance to streptomycin/spectinomycin. Most of the isolates were considered resistant to quaternary ammonium compounds and all of them carried the qacEΔ1 gene at the 3' conserved segment of the integron. ERIC-PCR analyses of E. coli isolates that presented the integrons showed great genetic diversity, indicating diverse sources of contamination in this environment. These results suggest that fecal bacteria with class 1 integrons in aquatic environments are potentially important reservoirs of antibiotic-resistance genes and may transfer these elements to other bacteria that are capable of infecting humans. | 2016 | 26991286 |
| 3559 | 2 | 0.9999 | Plasmid-Mediated Quinolone Resistance (PMQR) Genes and Class 1 Integrons in Quinolone-Resistant Marine Bacteria and Clinical Isolates of Escherichia coli from an Aquacultural Area. Antimicrobial usage in aquaculture selects for antimicrobial-resistant microorganisms in the marine environment. The relevance of this selection to terrestrial animal and human health is unclear. Quinolone-resistance genes qnrA, qnrB, and qnrS were chromosomally located in four randomly chosen quinolone-resistant marine bacteria isolated from an aquacultural area with heavy quinolone usage. In quinolone-resistant uropathogenic clinical isolates of Escherichia coli from a coastal area bordering the same aquacultural region, qnrA was chromosomally located in two E. coli isolates, while qnrB and qnrS were located in small molecular weight plasmids in two other E. coli isolates. Three quinolone-resistant marine bacteria and three quinolone-resistant E. coli contained class 1 integrons but without physical association with PMQR genes. In both marine bacteria and uropathogenic E. coli, class 1 integrons had similar co-linear structures, identical gene cassettes, and similarities in their flanking regions. In a Marinobacter sp. marine isolate and in one E. coli clinical isolate, sequences immediately upstream of the qnrS gene were homologous to comparable sequences of numerous plasmid-located qnrS genes while downstream sequences were different. The observed commonality of quinolone resistance genes and integrons suggests that aquacultural use of antimicrobials might facilitate horizontal gene transfer between bacteria in diverse ecological locations. | 2018 | 28642992 |
| 3554 | 3 | 0.9999 | Transmissible Plasmids and Integrons Shift Escherichia coli Population Toward Larger Multiple Drug Resistance Numbers. Transmissible plasmids and integrons may play important roles in the persistence and spread of antibiotic-resistant bacteria throughout aquatic environment by accumulating antibiotic resistance genes (ARG). Class 1 and class 2 integron (intI), mobilization (mob), sulfamethoxazole resistance (sul), and trimethoprim resistance (dfr) genes were PCR-amplified and confirmed through DNA sequencing following plasmid extraction from 139 antibiotic-resistant Escherichia coli. E. coli had previously been recovered from wastewater treatment plant effluent and receiving stream water in Northwest Arkansas and isolates had expressed resistance to one to six antibiotics. Almost half of the total isolates (47%) carried putatively transmissible plasmids with mob(F12) gene as the most frequently detected mobilization gene. When two or three mob genes were detected per isolate, there was a significant shift in the population toward larger multiple drug resistance (MDR) number. Class 1 and/or 2 integrons were prevalent (46%), and the presence of integron significantly shifted the isolate population toward larger MDR number. More isolates carried single or coexistence of two or three sul genes (99.3%), and single or a combination up to five dfr genes (89.3%) than had exhibited in vitro resistance to the respective antibiotics. These findings indicate not only the role of the wastewater treatment effluent and the stream environment in coaccumulation of ARG with transmissible plasmids and integrons in multiple antibiotic-resistant E. coli populations but also suggest that density of sul and dfr resistance genes within an isolate may serve as a biomarker for mobile MDR in general. | 2018 | 29058514 |
| 3555 | 4 | 0.9998 | Antimicrobial resistance and antimicrobial resistance genes in marine bacteria from salmon aquaculture and non-aquaculture sites. Antimicrobial resistance (AR) detected by disc diffusion and antimicrobial resistance genes detected by DNA hybridization and polymerase chain reaction with amplicon sequencing were studied in 124 marine bacterial isolates from a Chilean salmon aquaculture site and 76 from a site without aquaculture 8 km distant. Resistance to one or more antimicrobials was present in 81% of the isolates regardless of site. Resistance to tetracycline was most commonly encoded by tetA and tetG; to trimethoprim, by dfrA1, dfrA5 and dfrA12; to sulfamethizole, by sul1 and sul2; to amoxicillin, by blaTEM ; and to streptomycin, by strA-strB. Integron integrase intl1 was detected in 14 sul1-positive isolates, associated with aad9 gene cassettes in two from the aquaculture site. intl2 Integrase was only detected in three dfrA1-positive isolates from the aquaculture site and was not associated with gene cassettes in any. Of nine isolates tested for conjugation, two from the aquaculture site transferred AR determinants to Escherichia coli. High levels of AR in marine sediments from aquaculture and non-aquaculture sites suggest that dispersion of the large amounts of antimicrobials used in Chilean salmon aquaculture has created selective pressure in areas of the marine environment far removed from the initial site of use of these agents. | 2014 | 24612265 |
| 5554 | 5 | 0.9998 | High prevalence of multidrug-tolerant bacteria and associated antimicrobial resistance genes isolated from ornamental fish and their carriage water. BACKGROUND: Antimicrobials are used to directly control bacterial infections in pet (ornamental) fish and are routinely added to the water these fish are shipped in to suppress the growth of potential pathogens during transport. METHODOLOGY/PRINCIPAL FINDINGS: To assess the potential effects of this sustained selection pressure, 127 Aeromonas spp. isolated from warm and cold water ornamental fish species were screened for tolerance to 34 antimicrobials. Representative isolates were also examined for the presence of 54 resistance genes by a combination of miniaturized microarray and conventional PCR. Forty-seven of 94 Aeromonas spp. isolates recovered from tropical ornamental fish and their carriage water were tolerant to > or =15 antibiotics, representing seven or more different classes of antimicrobial. The quinolone and fluoroquinolone resistance gene, qnrS2, was detected at high frequency (37% tested recent isolates were positive by PCR). Class 1 integrons, IncA/C broad host range plasmids and a range of other antibiotic resistance genes, including floR, bla(TEM-1), tet(A), tet(D), tet(E), qacE2, sul1, and a number of different dihydrofolate reductase and aminoglycoside transferase coding genes were also detected in carriage water samples and bacterial isolates. CONCLUSIONS: These data suggest that ornamental fish and their carriage water act as a reservoir for both multi-resistant bacteria and resistance genes. | 2009 | 20027306 |
| 5555 | 6 | 0.9998 | New sequence types and multidrug resistance among pathogenic Escherichia coli isolates from coastal marine sediments. The spread of antibiotic-resistant microorganisms is widely recognized, but data about their sources, presence, and significance in marine environments are still limited. We examined 109 Escherichia coli strains from coastal marine sediments carrying virulence genes for antibiotic susceptibility, specific resistance genes, prevalence of class 1 and 2 integrons, and sequence type. Antibiotic resistance was found in 35% of strains, and multiple resistances were found in 14%; the resistances detected most frequently were against tetracycline (28%), ampicillin (16.5%), trimethoprim-sulfamethoxazole (13%), and streptomycin (7%). The highest prevalence of resistant strains was in phylogenetic group A, whereas phylogroup B2 exhibited a significantly lower frequency than all the other groups. Sixty percent of multiresistant strains harbored class 1 or 2 integrase genes, and about 50% carried resistance genes (particularly dfrA and aadA) linked to a class 1 integron. Multilocus sequence typing of 14 selected strains identified eight different types characteristic of extraintestinal pathogens and three new allelic combinations. Our data suggest that coastal marine sediment may be a suitable environment for the survival of pathogenic and antimicrobial-resistant E. coli strains capable of contributing to resistance spread via integrons among benthic bacteria, and they highlight a role for these strains in the emergence of new virulent genotypes. | 2012 | 22447595 |
| 3355 | 7 | 0.9998 | Occurrence and characterization of plasmid-encoded qnr genes in quinolone-resistant bacteria across diverse aquatic environments in southern Ontario. Antimicrobial resistance is an ever-increasing threat. The widespread usage of ciprofloxacin has led to the manifestation of resistance due to chromosomal mutations or the acquisition of plasmid-mediated quinolone resistance (PMQR) traits. Some particular PMQR traits, qnr genes, have been identified globally in clinical and environmental isolates. This study aimed to determine the prevalence of ciprofloxacin-resistant bacteria in aquatic environments in southern Ontario and investigate the extent of dissemination of ciprofloxacin resistance traits among the bacterial communities. We surveyed the prevalence of plasmid encoding qnr genes using a multiplex PCR assay of associated PMQR genes, qnrA, qnrB, and qnrS, on 202 isolates. Despite the absence of significant impacts on minimum inhibitory concentration levels, the presence of qnr genes correlates with heightened resistance to quinolones and nalidixic acid in some isolates. Taxonomic analysis highlights distinct differences in the composition and diversity of ciprofloxacin-sensitive (CipS) and ciprofloxacin-resistant (CipR) populations, with Proteobacteria dominating both groups. Importantly, CipR populations exhibit lower genetic diversity but higher prevalence of multiple antibiotic resistances, suggesting co-selection mechanisms. Co-occurrence analysis highlights significant associations between ciprofloxacin resistance and other antibiotic resistances, implicating complex genetic linkages. The results of our study signified the critical role of environmental monitoring in public health. | 2024 | 39083844 |
| 2853 | 8 | 0.9998 | Antibiotic resistance and virulence genes in coliform water isolates. Widespread fecal pollution of surface water may present a major health risk and a significant pathway for dissemination of antibiotic resistance bacteria. The River Rhine is one of the longest and most important rivers in Europe and an important raw water source for drinking water production. A total of 100 coliform isolates obtained from River Rhine (Germany) were examined for their susceptibility to seven antimicrobial agents. Resistances against amoxicillin, trimethoprim/sulfamethoxazole and tetracycline were detected in 48%, 11% and 9% of isolates respectively. The antibiotic resistance could be traced back to the resistance genes bla(TEM), bla(SHV), ampC, sul1, sul2, dfrA1, tet(A) and tet(B). Whereby, the ampC gene represents a special case, because its presence is not inevitably linked to a phenotypic antibiotic resistance. Multiple antibiotics resistance was often accompanied by the occurrence of class 1 or 2 integrons. E. coli isolates belonging to phylogenetic groups A and B1 (commensal) were more predominant (57%) compared to B2 and D groups (43%) which are known to carry virulent genes. Additionally, six E. coli virulence genes were also detected. However, the prevalence of virulence genes in the E. coli isolates was low (not exceeding 4.3% per gene) and no diarrheagenic E. coli pathotypes were detected. This study demonstrates that surface water is an important reservoir of ARGs for a number of antibiotic classes such as sulfonamide, trimethoprim, beta-lactam-antibiotics and tetracycline. The occurrence of antibiotic resistance in coliform bacteria isolated from River Rhine provides evidence for the need to develop management strategies to limit the spread of antibiotic resistant bacteria in aquatic environment. | 2016 | 27497615 |
| 1930 | 9 | 0.9998 | Changes in dominant Escherichia coli and antimicrobial resistance after 24 hr in fecal matter. Intestinal bacteria carry antimicrobial resistance (AMR) genes in mobile genetic elements which have the potential to spread to bacteria in other animal hosts including humans. In fecal matter, Escherichia coli can continue to multiply for 48 hr after being excreted, and in certain environments, E. coli survive long periods of time. It is unclear the extent to which AMR in E. coli changes in the environment outside of its host. In this study, we analyzed changes in the population structure, plasmid content, and AMR patterns of 30 E. coli isolates isolated from 6 chickens (cloacal swabs), and 30 E. coli isolates from fecal samples (from the same 6 chickens) after 24 hr of incubation. Clonality of isolates was screened using the fumC gene sequence and confirmed in a subset of isolates (n = 14) by multi-locus sequence typing. Major shifts in the population structure (i.e., sequence types) and antibiotic resistance patterns were observed among the numerically dominant E. coli isolates after 24 hr. Four E. coli clones isolated from the cloaca swabs and the corresponding fecal samples (after 24 hr incubation) showed different antibiotic resistance patterns. Our study reveals that fecal matter in the environment is an intermediate habitat where rapid and striking changes occur in E. coli populations and antibiotic resistance patterns. | 2019 | 29896865 |
| 3553 | 10 | 0.9998 | Genetic redundancy and persistence of plasmid-mediated trimethoprim/sulfamethoxazole resistant effluent and stream water Escherichia coli. Antibiotic resistant bacteria may persist in effluent receiving surface water in the presence of low (sub-inhibitory) antibiotic concentrations if the bacteria possess multiple genes encoding resistance to the same antibiotic. This redundancy of antibiotic resistance genes may occur in plasmids harboring conjugation and mobilization (mob) and integrase (intI) genes. Plasmids extracted from 76 sulfamethoxazole-trimethoprim resistant Escherichia coli originally isolated from effluent and an effluent-receiving stream were used as DNA template to identify sulfamethoxazole (sul) and trimethoprim (dfr) resistances genes plus detect the presence of intI and mob genes using PCR. Sulfamethoxazole and trimethoprim resistance was plasmid-mediated with three sul (sul1, sul2 and sul3 genes) and four dfr genes (dfrA12, dfrA8, dfrA17, and dfrA1 gene) the most prevalently detected. Approximately half of the plasmids carried class 1 and/or 2 integron and, although unrelated, half were also transmissible. Sampling site in relationship to effluent input significantly affected the number of intI and mob but not the number of sul and dfr genes. In the presence of low (sub-inhibitory) sulfamethoxazole concentration, isolates persisted regardless of integron and mobilization gene designation, whereas in the presence of trimethoprim, the presence of both integron and mobilization genes made isolates less persistent than in the absence of both or the presence of a gene from either group individually. Regardless, isolates persisted in large concentrations throughout the experiment. Treated effluent containing antibiotic resistant bacteria may be an important source of integrase and mobilization genes into the stream environment. Sulfamethoxazole-trimethoprim resistant bacteria may have a high degree of genetic redundancy and diversity carrying resistance to each antibiotic, although the role of integrase and mobilization genes towards persistence is unclear. | 2016 | 27455416 |
| 3356 | 11 | 0.9998 | Conjugative multiple-antibiotic resistance plasmids in Escherichia coli isolated from environmental waters contaminated by human faecal wastes. AIMS: To better understand the involvement of faecal contamination in the dissemination of antibiotic resistance genes, we investigated the genetic supports of resistances in nine multi-resistant Escherichia coli strains originating from human faecal contamination, and isolated from three different aquatic environments used for producing drinking water. METHODS AND RESULTS: Seven strains harboured at least one large plasmid that we have characterized (size, antibiotic resistance patterns, incompatibility group, capacity of autotransfer, presence of integron). Most of these plasmids were conjugative and carried numerous resistances. One of the plasmids studied, belonging to the IncP incompatibility group, was able to transfer by conjugation to Pseudomonas fluorescens and Aeromonas sp. Only two of the plasmids we studied carried class 1 and/or 2 integron(s). CONCLUSIONS: Conjugative plasmids isolated from multi-resistant E. coli strains explained most of the resistances of their host strains and probably contribute to the spread of antibiotic resistance genes coming from human faecal contamination. SIGNIFICANCE AND IMPACT OF THE STUDY: These results highlight the key role played by plasmids in the multi-resistance phenotype of faecal bacteria and the diversity of these genetic structures. Contaminated water, especially accidentally contaminated drinking water, could be a path back to humans for these plasmids. | 2015 | 25387599 |
| 1931 | 12 | 0.9998 | The level of antimicrobial resistance of sewage isolates is higher than that of river isolates in different Escherichia coli lineages. The dissemination of antimicrobial-resistant bacteria in environmental water is an emerging concern in medical and industrial settings. Here, we analysed the antimicrobial resistance of Escherichia coli isolates from river water and sewage by the use of a combined experimental phenotypic and whole-genome-based genetic approach. Among the 283 tested strains, 52 were phenotypically resistant to one or more antimicrobial agents. The E. coli isolates from the river and sewage samples were phylogenetically indistinguishable, and the antimicrobial-resistant strains were dispersedly distributed in a whole-genome-based phylogenetic tree. The prevalence of antimicrobial-resistant strains as well as the number of antimicrobials to which they were resistant were higher in sewage samples than in river samples. Antimicrobial resistance genes were more frequently detected in strains from sewage samples than in those from river samples. We also found that 16 river isolates that were classified as Escherichia cryptic clade V were susceptible to all the antimicrobials tested and were negative for antimicrobial resistance genes. Our results suggest that E. coli strains may acquire antimicrobial resistance genes more frequently and/or antimicrobial-resistant E. coli strains may have higher rates of accumulation and positive selection in sewage than in rivers, irrespective of their phylogenetic distribution. | 2020 | 33087784 |
| 2856 | 13 | 0.9998 | Multiresistant Enterobacteriaceae with class 1 and class 2 integrons in a municipal wastewater treatment plant. In this study, 1832 strains of the family Enterobacteriaceae were isolated from different stages of a municipal wastewater treatment plant, of which 221 (12.1%) were intI-positive. Among them 61.5% originated from raw sewage, 12.7% from aeration tank and 25.8% from the final effluent. All of the intI-positive strains were multiresistant, i.e. resistant to at least three unrelated antimicrobials. Although there were no significant differences in resistance range, defined as the number of antimicrobial classes to which an isolate was resistant, between strains isolated from different stages of wastewater treatment, for five β-lactams the percentage of resistant isolates was the highest in final effluent, which may reflect a selective pressure the bacteria are exposed to, and the possible route of dissemination of β-lactam resistant strains to the corresponding river. The sizes of the variable part of integrons ranged from 0.18 to 3.0 kbp and contained up to four incorporated gene cassettes. Sequence analysis identified over 30 different gene cassettes, including 24 conferring resistance to antibiotics. The highest number of different gene cassettes was found in bacteria isolated from the final effluent. The gene cassettes were arranged in 26 different resistance cassette arrays; the most often were dfrA1-aadA1, aadA1, dfrA17-aadA5 and dfrA12-orfF-aadA2. Regarding the diversity of resistance genes and the number of multiresistant bacteria in the final effluent, we concluded that municipal sewage may serve as a reservoir of integron-embedded antibiotic resistance genes. | 2012 | 22507248 |
| 2833 | 14 | 0.9998 | Heavy metal resistance genes and plasmid-mediated quinolone resistance genes in Arthrobacter sp. isolated from Brazilian soils. Arthrobacter sp. are Gram-positive bacilli commonly obtained from soil and in the hospital environment. These species have been reported to cause several types of infection. Heavy metals are a threat to the ecological system due to their high-levels of toxicity and the fluoroquinolones are antimicrobials widely used for the treatment of different bacterial infections. The aim of this study was to investigate the resistance to fluoroquinolone and heavy metals, the presence of plasmid-mediated resistance (PMQR) genes and heavy metals resistance (HMR) genes and the presence of plasmids in Arthrobacter sp. obtained from Brazilian soils. Bacterial isolation was performed using soil samples from different Brazilian regions. The bacterial identification was performed by 16S rRNA gene sequencing. The resistance profile for fluoroquinolones and heavy metals was determined by MIC. Several PMQR and HMR genes and plasmid families were investigated by PCR. Eight isolates were obtained from soil samples from different cultivations and regions of Brazil. All isolates were resistant to all fluoroquinolones, cadmium, cobalt and zinc and the majority to copper. Among the PMQR genes, the qepA (4) was the most prevalent, followed by qnrS (3), qnrB (3), oqxB (2) and oqxA (1). Among the HMR genes, the copA was detected in all isolates and the czcA in two isolates. The replication origin of the ColE-like plasmid was detected in all isolates; however, no plasmid was detected by extraction. The association of resistance to heavy metals and antimicrobials is a threat to the environmental balance and to human health. There are no studies reporting the association of PMQR and HMR genes in bacteria belonging to the genus Arthrobacter. To the best of our knowledge, this is the first report of qnrB, qepA, oqxA and oqxB in Arthrobacter species. | 2019 | 31129890 |
| 2829 | 15 | 0.9998 | Prevalence of streptomycin-resistance genes in bacterial populations in European habitats. The prevalence of selected streptomycin (Sm)-resistance genes, i.e. aph (3''), aph (6)-1d, aph (6)-1c, ant (3'') and ant (6), was assessed in a range of pristine as well as polluted European habitats. These habitats included bulk and rhizosphere soils, manure from farm animals, activated sludge from wastewater treatment plants and seawater. The methods employed included assessments of the prevalence of the genes in habitat-extracted DNA by PCR, followed by hybridisation with specific probes, Sm-resistant culturable bacteria and exogenous isolation of plasmids carrying Sm-resistance determinants. The direct DNA-based analysis showed that aph (6)-1d genes were most prevalent in the habitats examined. The presence of the other four Sm-modifying genes was demonstrated in 58% of the tested habitats. A small fraction of the bacterial isolates (8%) did not possess any of the selected Sm-modifying genes. These isolates were primarily obtained from activated sludge and manure. The presence of Sm-modifying genes in the isolates often coincided with the presence of IncP plasmids. Exogenous isolation demonstrated the presence of plasmids of 40-200 kb in size harbouring Sm-resistance genes from all the environments tested. Most plasmids were shown to carry the ant (3'') gene, often in combination with other Sm-resistance genes, such as aph (3'') and aph (6)-1d. The most commonly found Sm-modifying gene on mobile genetic elements was ant (3''). Multiple Sm-resistance genes on the same genetic elements appeared to be the rule rather than the exception. It is concluded that Sm-resistance genes are widespread in the environmental habitats studied and often occur on mobile genetic elements and ant (3'') was most often encountered. | 2002 | 19709288 |
| 1940 | 16 | 0.9998 | Plasmid-mediated multiple antibiotic resistance of Escherichia coli in crude and treated wastewater used in agriculture. A total of 273 Escherichia coli isolates from raw and treated municipal wastewaters were investigated to evaluate the frequency and persistence of antibiotic resistance and to detect the occurrence of conjugative R plasmids and integrons. The highest resistance rates were against ampicillin (22.71%), tetracycline (19.41%), sulfamethoxazole (16.84%) and streptomycin (14.28%). Multiple antibiotic resistance was present in 24.17% of the isolates. Several multiple antibiotic-resistant isolates proved to be able to transfer en bloc their resistance patterns by conjugative R plasmids with different molecular sizes and restriction profiles. Class 1 integrons of 1 or 1.5 kbp were found in 5 out of 24 representative multiresistant E. coli isolates. Although wastewater treatments proved to be effective in eliminating Salmonella spp. and in reaching WHO microbiological standards for safe use of wastewater in agriculture, they were ineffective in reducing significantly the frequency of plasmid-mediated multiple antibiotic resistance in surviving E. coli. Since multiple antibiotic-resistant bacteria carrying integrons and conjugative R plasmids can constitute a reservoir of antibiotic-resistance genes in wastewater reclaimed for irrigation, risks for public health should be considered. Bacterial strains carrying R plasmids and integrons could contaminate crops irrigated with reclaimed wastewater and transfer their resistances to the consumers' intestinal bacteria. | 2009 | 19240351 |
| 1934 | 17 | 0.9998 | Sulfonamide resistance evaluation in five animal species and first report of sul4 in companion animals. Sulfonamides are one of the oldest groups of antibacterial agents with a broad-spectrum, used as first line treatment in bacterial infections. Their widespread use produced a selective pressure on bacteria, as observed by the high incidence of sulfonamides resistance mainly in Gram negative bacteria isolated from animals. In this research, the presence of sulfonamide resistance genes (sul1, sul2, sul3, and sul4) in phenotypically resistant Escherichia coli isolates has been studied. These genes were amplified in isolates recovered from five animal species, with different interactions to humans: cattle, swine, poultry as livestock, and dogs and cats as companion animals. Isolates were collected according to their phenotypic resistance, and the magnetic bead-based Luminex technology was applied to simultaneously detect sul target genes. The frequency of sul genes was highest in swine, among livestock isolates. The sul1 and sul2 were the most frequently sulfonamide resistance genes detected in all phenotypically resistant isolates. Notably, in companion animals, with a closest interaction with human, sul4 gene was detected. To our knowledge, this is the first report of the presence of sul4 gene in E. coli collected from animals, whereas previously the presence of this gene was reported in environmental, municipal wastewater and human clinical isolates. These results highlighted the importance of continuous antimicrobial resistant genes monitoring in animal species, with a special care to companion animals. | 2024 | 39029236 |
| 3391 | 18 | 0.9998 | Phenotypic and genotypic analysis of bacteria isolated from three municipal wastewater treatment plants on tetracycline-amended and ciprofloxacin-amended growth media. AIMS: The goal of this study was to determine the antimicrobial susceptibility of bacteria isolated from three municipal wastewater treatment plants. METHODS AND RESULTS: Numerous bacterial strains were isolated from three municipal wastewater treatment facilities on tetracycline- (n=164) and ciprofloxacin-amended (n=65) growth media. These bacteria were then characterized with respect to their resistance to as many as 10 different antimicrobials, the presence of 14 common genes that encode resistance to tetracycline, the presence of integrons and/or the ability to transfer resistance via conjugation. All of the characterized strains exhibited some degree of multiple antimicrobial resistance, with nearly 50% demonstrating resistance to every antimicrobial that was tested. Genes encoding resistance to tetracycline were commonly detected among these strains, although intriguingly the frequency of detection was slightly higher for the bacteria isolated on ciprofloxacin-amended growth media (62%) compared to the bacteria isolated on tetracycline-amended growth media (53%). Class 1 integrons were also detected in 100% of the queried tetracycline-resistant bacteria and almost half of the ciprofloxacin-resistant strains. Conjugation experiments demonstrated that at least one of the tetracycline-resistant bacteria was capable of lateral gene transfer. CONCLUSIONS: Our results demonstrate that multiple antimicrobial resistance is a common trait among tetracycline-resistant and ciprofloxacin-resistant bacteria in municipal wastewater. SIGNIFICANCE AND IMPACT OF THE STUDY: These organisms are potentially important in the proliferation of antimicrobial resistance because they appear to have acquired multiple genetic determinants that confer resistance and because they have the potential to laterally transfer these genetic determinants to strains of clinical importance. | 2010 | 20629799 |
| 2797 | 19 | 0.9998 | Widespread distribution of tetracycline resistance genes in a confined animal feeding facility. We sought to determine the distribution of resistance and the tetracycline resistance genes among bacteria isolated from a swine confined animal feeding facility where tetracycline-containing feed had been in use for over 20 years. Samples collected from feed, hogs, hog houses, waste lagoon, soil, surface water and well water were screened for the presence of (a) resistant Escherichia coli and enterococci and (b) tetracycline-resistant strains of all species. Genomic DNA was extracted from the latter strain collection and fragments from 16S rDNA and ten tetracycline resistance genes (tetA, tetB, tetC, tetE, tetH, tetL, tetM, tetS, tetT and rumB) were polymerase chain reaction-amplified and a partial nucleotide sequence was obtained. In this environment, 77% of E. coli and 68% of enterococci isolated were tetracycline resistant. Tetracycline resistance was found in 26 different bacterial genera and in 60 species. Single resistance gene alleles (as defined by nucleotide sequence) were present in multiple species. There was evidence of gene recombination and multiple different tetracycline resistance genes were present in single bacterial isolates. These data provide further evidence for the widespread distribution of resistance genes in microbial populations in settings in which there is ongoing subtherapeutic antimicrobial use. | 2007 | 17287111 |