# | Rank | Similarity | Title + Abs. | Year | PMID |
|---|---|---|---|---|---|
| 0 | 1 | 2 | 3 | 4 | 5 |
| 1775 | 0 | 0.8878 | The IncC and IncX1 resistance plasmids present in multi-drug resistant Escherichia coli strains isolated from poultry manure in Poland. The study describes the whole-genome sequencing of two antibiotic-resistant representative Escherichia coli strains, isolated from poultry manure in 2020. The samples were obtained from a commercial chicken meat production facility in Poland. The antibiotic resistance profile was characterized by co-resistance to β-lactam antibiotics, aminoglycosides, and fluoroquinolones. The three identified resistance plasmids (R-plasmids), pECmdr13.2, pECmdr13.3, and pECmdr14.1, harbored various genes conferring resistance to tetracyclines (tetR[A]) for, aminoglycoside (aph, aac, and aad families), β-lactam (bla(CMY-2), bla(TEM-176)), sulfonamide (sul1, sul2), fluoroquinolone (qnrS1), and phenicol (floR). These plasmids, which have not been previously reported in Poland, were found to carry IS26 insertion elements, the intI1-integrase gene, and conjugal transfer genes, facilitating horizontal gene transfer. Plasmids pECmdr13.2 and pECmdr14.1 also possessed a mercury resistance gene operon related to transposon Tn6196; this promotes plasmid persistence even without antibiotic selection pressure due to co-selection mechanisms such as co-resistance. The chicken manure-derived plasmids belonged to the IncX1 (narrow host range) and IncC (broad host range) incompatibility groups. Similar plasmids have been identified in various environments, clinical isolates, and farm animals, including cattle, swine, and poultry. This study holds significant importance for the One Health approach, as it highlights the potential for antibiotic-resistant bacteria from livestock and food sources, particularly E. coli, to transfer through the food chain to humans and vice versa. | 2024 | 39007976 |
| 1752 | 1 | 0.8873 | Genetic Characterization of a Linezolid- and Penicillin-Resistant Enterococcus hirae Isolate Co-Harboring poxtA and pbp5fm. Linezolid and penicillin are critical for treating multidrug resistant (MDR) Gram-positive infections, but the emergence of resistance to both seriously threatens public health. Here, we first report the cocarrying poxtA (oxazolidinone resistance) and pbp5fm (β-lactam resistance) genes by the plasmid in a strain of Enterococcus hirae HDC14-2 derived from porcine. The isolate also exhibits MDR phenotypes to phenicols, oxazolidinones, tetracyclines, β-lactams, aminoglycosides, macrolides, and lincosamides. Whole-genome sequencing (WGS) revealed these resistance genes, along with tet(L), tet(M), catA, erm(B), aac(6)-aph(2"), aadE, spw, lsa(E), lnu(B), sat4, and aphA3, were clustered in a novel MDR region flanked by IS1216 elements on plasmid pHDC14-2.133K. This IS1216-bounded MDR region formed translocatable units (TUs), including an IS1216-poxtA TU that was also identified on a secondary plasmid, pHDC14-2.27K. Functional assays demonstrated the excisability and mobility of these TUs, indicating its potential ability integration into other plasmids or chromosomes. Critically, electrotransformation confirmed the transfer of pHDC14-2.27K (poxtA-carrying) to Enterococcus faecalis JH2-2, with retained TU activity and minimal fitness cost. This study provides the evidence of colocalized poxtA and pbp5fm on plasmids in enterococci, highlighting their role in disseminating pan-resistance among bacteria. Although E. hirae is not an important pathogenic bacterium to humans and animals, but its potential risk to horizontally spread of these resistance genes important in medicine still cannot be ignored. | 2025 | 40692874 |
| 1535 | 2 | 0.8858 | Complete Genome Sequencing of Acinetobacter baumannii AC1633 and Acinetobacter nosocomialis AC1530 Unveils a Large Multidrug-Resistant Plasmid Encoding the NDM-1 and OXA-58 Carbapenemases. Carbapenem-resistant Acinetobacter spp. are considered priority drug-resistant human-pathogenic bacteria. The genomes of two carbapenem-resistant Acinetobacter spp. clinical isolates obtained from the same tertiary hospital in Terengganu, Malaysia, namely, A. baumannii AC1633 and A. nosocomialis AC1530, were sequenced. Both isolates were found to harbor the carbapenemase genes bla(NDM-1) and bla(OXA-58) in a large (ca. 170 kb) plasmid designated pAC1633-1 and pAC1530, respectively, that also encodes genes that confer resistance to aminoglycosides, sulfonamides, and macrolides. The two plasmids were almost identical except for the insertion of ISAba11 and an IS4 family element in pAC1633-1, and ISAba11 along with relBE toxin-antitoxin genes flanked by inversely orientated pdif (XerC/XerD) recombination sites in pAC1530. The bla(NDM-1) gene was encoded in a Tn125 composite transposon structure flanked by ISAba125, whereas bla(OXA-58) was flanked by ISAba11 and ISAba3 downstream and a partial ISAba3 element upstream within a pdif module. The presence of conjugative genes in plasmids pAC1633-1/pAC1530 and their discovery in two distinct species of Acinetobacter from the same hospital are suggestive of conjugative transfer, but mating experiments failed to demonstrate transmissibility under standard laboratory conditions. Comparative sequence analysis strongly inferred that pAC1633-1/pAC1530 was derived from two separate plasmids in an IS1006-mediated recombination or transposition event. A. baumannii AC1633 also harbored three other plasmids designated pAC1633-2, pAC1633-3, and pAC1633-4. Both pAC1633-3 and pAC1633-4 are cryptic plasmids, whereas pAC1633-2 is a 12,651-bp plasmid of the GR8/GR23 Rep3-superfamily group that encodes the tetA(39) tetracycline resistance determinant in a pdif module.IMPORTANCE Bacteria of the genus Acinetobacter are important hospital-acquired pathogens, with carbapenem-resistant A. baumannii listed by the World Health Organization as the one of the top priority pathogens. Whole-genome sequencing of carbapenem-resistant A. baumannii AC1633 and A. nosocomialis AC1530, which were isolated from the main tertiary hospital in Terengganu, Malaysia, led to the discovery of a large, ca. 170-kb plasmid that harbored genes encoding the New Delhi metallo-β-lactamase-1 (NDM-1) and OXA-58 carbapenemases alongside genes that conferred resistance to aminoglycosides, macrolides, and sulfonamides. The plasmid was a patchwork of multiple mobile genetic elements and comparative sequence analysis indicated that it may have been derived from two separate plasmids through an IS1006-mediated recombination or transposition event. The presence of such a potentially transmissible plasmid encoding resistance to multiple antimicrobials warrants vigilance, as its spread to susceptible strains would lead to increasing incidences of antimicrobial resistance. | 2021 | 33504662 |
| 827 | 3 | 0.8854 | Characterization of a ST137 multidrug-resistant Campylobacter jejuni strain with a tet(O)-positive genomic island from a bloodstream infection patient. Campylobacter jejuni (C. jejuni) is a major cause of gastroenteritis and rarely cause bloodstream infection. Herein, we characterized a multidrug-resistant C. jejuni strain LZCJ isolated from a tumor patient with bloodstream infection. LZCJ was resistant to norfloxacin, ampicillin, ceftriaxone, ciprofloxacin and tetracycline. It showed high survival rate in serum and acidic environment. Whole genome sequencing (WGS) analysis revealed that strain LZCJ had a single chromosome of 1,629,078 bp (30.6 % G + C content) and belonged to the ST137 lineage. LZCJ shared the highest identity of 99.66 % with the chicken-derived C. jejuni MTVDSCj20. Four antimicrobial resistance genes (ARGs) were detected, bla(OXA-61), tet(O), gyrA (T86I), and cmeR (G144D and S207G). In addition, a 12,746 bp genomic island GI_LZCJ carrying 15 open reading frames (ORFs) including the resistance gene tet(O) was identified. Sequence analysis found that the GI_LZCJ was highly similar to the duck-derived C. jejuni ZS004, but with an additional ISChh1-like sequence. 137 non-synonymous mutations in motility related genes (flgF, fapR, flgS), capsular polysaccharide (CPS) coding genes (kpsE, kpsF, kpsM, kpsT), metabolism associated genes (nuoF, nuoG, epsJ, holB), and transporter related genes (comEA, gene0911) were confirmed in LZCJ compared with the best closed chicken-derived strain MTVDSCj20. Our study showed that C. jejuni strain LZCJ was highly similar to the chicken-derived strain MTVDSCj20 but with a lot of SNPs involved in motility, CPS and metabolism coding genes. This strain possessed a tet(O)-positive genomic island GI_LZCJ, which was closed to duck-derived C. jejuni ZS004, but with an additional ISChh1-like sequence. The above data indicated that the LZCJ strain may originate from foodborne bacteria on animals and the importance of continuous surveillance for the spread of foodborne bacteria. | 2024 | 39208964 |
| 3030 | 4 | 0.8845 | Mobile Genomic Island GEI-FN1A in Aeromonas salmonicida FN1 Contributes to the Spread of Antibiotic-Resistance Genes. Antibiotics are used to treat severe bacterial infections. However, owing to excessive antibiotic use, bacteria under high selective pressure for antibiotics develop resistance through spontaneous mutation or by acquiring antibiotic-resistance genes (ARGs) through horizontal gene transfer (HGT). Horizontal transfer of ARGs among bacteria in the environment can lead to the emergence of multidrug-resistant (MDR) bacteria that infect animals and humans, thus causing disease outbreaks. In this study, MDR strain FN1 was isolated from a feces-contaminated soil sample from a chicken farm under pressure from the antibiotic florfenicol (16 mg/L) and identified as Aeromonas salmonicida. Whole-genome sequencing and analysis revealed the 86.8-kb antibiotic-resistant genomic island, GEI-FN1A, in the FN1 genome. Genome annotation revealed that GEI-FN1A carried several ARGs, including two tetracycline-resistance genes [tetR and tet(A)], three aminoglycoside-resistance genes [aph(6), aph(3"), and aac(3)], one trimethoprim-resistance gene (dfrB4), two chloramphenicol/florfenicol-resistance genes (catB3 and floR), three macrolide-resistance genes [mphR(A), mrx(A), and mph(A)] and two sul1 genes. GEI-FN1A also contained genes encoding integrase, transposase, and recombinase, which mediate the horizontal transfer of MDR genes. These findings suggest that GEI-FN1A in A. salmonicida FN1 can potentially spread ARGs among environmental bacteria. | 2025 | 40553200 |
| 1388 | 5 | 0.8844 | Snapshot Study of Whole Genome Sequences of Escherichia coli from Healthy Companion Animals, Livestock, Wildlife, Humans and Food in Italy. Animals, humans and food are all interconnected sources of antimicrobial resistance (AMR), allowing extensive and rapid exchange of AMR bacteria and genes. Whole genome sequencing (WGS) was used to characterize 279 Escherichia coli isolates obtained from animals (livestock, companion animals, wildlife), food and humans in Italy. E. coli predominantly belonged to commensal phylogroups B1 (46.6%) and A (29%) using the original Clermont criteria. One hundred and thirty-six sequence types (STs) were observed, including different pandemic (ST69, ST95, ST131) and emerging (ST10, ST23, ST58, ST117, ST405, ST648) extraintestinal pathogenic Escherichia coli (ExPEC) lineages. Eight antimicrobial resistance genes (ARGs) and five chromosomal mutations conferring resistance to highest priority critically important antimicrobials (HP-CIAs) were identified (qnrS1, qnrB19, mcr-1, bla(CTX-M1,15,55), bla(CMY-2), gyrA/parC/parE, ampC and pmrB). Twenty-two class 1 integron arrangements in 34 strains were characterized and 11 ARGs were designated as intI1 related gene cassettes (aadA1, aadA2, aadA5, aad23, ant2_Ia, dfrA1, dfrA7, dfrA14, dfrA12, dfrA17, cmlA1). Notably, most intI1 positive strains belonged to rabbit (38%) and poultry (24%) sources. Three rabbit samples carried the mcr-1 colistin resistance gene in association with IS6 family insertion elements. Poultry meat harbored some of the most prominent ExPEC STs, including ST131, ST69, ST10, ST23, and ST117. Wildlife showed a high average number of virulence-associated genes (VAGs) (mean = 10), mostly associated with an ExPEC pathotype and some predominant ExPEC lineages (ST23, ST117, ST648) were identified. | 2020 | 33172096 |
| 3031 | 6 | 0.8843 | Novel Mobilizable Genomic Island GEI-D18A Mediates Conjugational Transfer of Antibiotic Resistance Genes in the Multidrug-Resistant Strain Rheinheimera sp. D18. Aquatic environments act as reservoirs of antimicrobial-resistant bacteria and antimicrobial resistance (AMR) genes, and the dissemination of antibiotic resistance from these environments is of increasing concern. In this study, a multidrug-resistant bacterial strain, identified as Rheinheimera sp. D18, was isolated from the sea water of an industrial maricultural system in the Yellow Sea, China. Whole-genome sequencing of D18 revealed the presence of a novel 25.8 kb antibiotic resistance island, designated GEI-D18A, which carries several antibiotic resistance genes (ARGs), including aadA1, aacA3, tetR, tet(B), catA, dfrA37, and three sul1 genes. Besides, integrase, transposase, resolvase, and recombinase encoding genes were also identified in GEI-D18A. The transferability of GEI-D18A was confirmed by mating experiments between Rheinheimera sp. D18 and Escherichia coli 25DN, and efflux pump inhibitor assays also suggested that tet(B) in GEI-D18A was responsible for tetracycline resistance in both D18 and the transconjugant. This study represents the first characterization of a mobilizable antibiotic resistance island in a species of Rheinheimera and provides evidence that Rheinheimera spp. could be important reservoirs and vehicles for ARGs in the Yellow Sea area. | 2020 | 32318052 |
| 1995 | 7 | 0.8836 | Genomic insights into Shigella species isolated from small ruminants and manure in the North West Province, South Africa. This study investigated Shigella species' antibiotic resistance patterns and genomic characteristics from small ruminants and manure collected in Potchefstroom, North West, South Africa. Whole genome sequencing was used to determine resistome profiles of Shigella flexneri isolates from small ruminants' manure and Shigella boydii from sheep faeces. Comparative genomics was employed on the South African 261 S. flexneri strains available from GenBank, including the sequenced strains in this study, by investigating the serovars, antibiotic resistance genes (ARGs), and plasmid replicon types. The S. flexneri strains could not be assigned to known sequence types, suggesting novel or uncharacterized lineages. S. boydii R7-1A was assigned to sequence type 202 (ST202). Serovar 2A was the most common among South African S. flexneri strains, found in 96% of the 250 compared human-derived isolates. The shared mdf(A) was the most prevalent gene, identified in 99% of 261 S. flexneri genomes, including plasmid replicon types ColRNAI_1 (99%) and IncFII_1 (98%). Both species share a core set of resistance determinants mainly involving β-lactams (ampC1, ampC, ampH), macrolides (mphB), polymyxins (eptA, pmrF), multidrug efflux pumps (AcrAB-TolC, Mdt, Emr, Kpn families), and regulatory systems (marA, hns, crp, baeRS, evgAS, cpxA, gadX). However, S. boydii possesses additional resistance genes conferring resistance to tetracyclines (tet(A)), phenicols (floR), sulphonamides (sul2), and aminoglycosides (APH(3'')-Ib, APH(6)-Id), along with the acrEF efflux pump components (acrE, acrF). In contrast, S. flexneri harboured unique genes linked to polymyxin resistance (ugd) and regulatory functions (sdiA, gadW) that were absent in S. boydii. These findings highlight Shigella strains' genomic diversity and antimicrobial resistance potential in livestock-associated environments. Moreover, S. boydii highlights the potential risk of multidrug-resistant bacteria in farming and environmental routes. KEY POINTS: • First whole genome study of Shigella from manure and small ruminants in South Africa. • Shigella boydii strain carried multiple resistance genes to β-lactams and tetracycline. • Multidrug efflux pump gene mdf(A) was detected in 99% of South African Shigella flexneri strains. | 2025 | 41148367 |
| 1992 | 8 | 0.8833 | Antimicrobial Resistance Genes, Cassettes, and Plasmids Present in Salmonella enterica Associated With United States Food Animals. The ability of antimicrobial resistance (AR) to transfer, on mobile genetic elements (MGEs) between bacteria, can cause the rapid establishment of multidrug resistance (MDR) in bacteria from animals, thus creating a foodborne risk to human health. To investigate MDR and its association with plasmids in Salmonella enterica, whole genome sequence (WGS) analysis was performed on 193 S. enterica isolated from sources associated with United States food animals between 1998 and 2011; 119 were resistant to at least one antibiotic tested. Isolates represented 86 serotypes and variants, as well as diverse phenotypic resistance profiles. A total of 923 AR genes and 212 plasmids were identified among the 193 strains. Every isolate contained at least one AR gene. At least one plasmid was detected in 157 isolates. Genes were identified for resistance to aminoglycosides (n = 472), β-lactams (n = 84), tetracyclines (n = 171), sulfonamides (n = 91), phenicols (n = 42), trimethoprim (n = 8), macrolides (n = 5), fosfomycin (n = 48), and rifampicin (n = 2). Plasmid replicon types detected in the isolates were A/C (n = 32), ColE (n = 76), F (n = 43), HI1 (n = 4), HI2 (n = 20), I1 (n = 62), N (n = 4), Q (n = 7), and X (n = 35). Phenotypic resistance correlated with the AR genes identified in 95.4% of cases. Most AR genes were located on plasmids, with many plasmids harboring multiple AR genes. Six antibiotic resistance cassette structures (ARCs) and one pseudo-cassette were identified. ARCs contained between one and five resistance genes (ARC1: sul2, strAB, tetAR; ARC2: aac3-iid; ARC3: aph, sph; ARC4: cmy-2; ARC5: floR; ARC6: tetB; pseudo-ARC: aadA, aac3-VIa, sul1). These ARCs were present in multiple isolates and on plasmids of multiple replicon types. To determine the current distribution and frequency of these ARCs, the public NCBI database was analyzed, including WGS data on isolates collected by the USDA Food Safety and Inspection Service (FSIS) from 2014 to 2018. ARC1, ARC4, and ARC5 were significantly associated with cattle isolates, while ARC6 was significantly associated with chicken isolates. This study revealed that a diverse group of plasmids, carrying AR genes, are responsible for the phenotypic resistance seen in Salmonella isolated from United States food animals. It was also determined that many plasmids carry similar ARCs. | 2019 | 31057528 |
| 1751 | 9 | 0.8833 | Strain Characterization of Streptococcus suis Serotypes 28 and 31, Which Harbor the Resistance Genes optrA and ant(6)-Ia. Streptococcus suis causes disease in pigs and is implicated increasingly in human disease worldwide. Although most clinical cases are associated with serotype 2, infections by other serotypes have sometimes been reported. Here, we sequenced the genome of a multidrug-resistant S. suis serotype 28 (strain 11313) and a multidrug-resistant S. suis serotype 31 (strain 11LB5). Strain 11313 was apathogenic in mouse infection models, whereas strain 11LB5 displayed ganglion demyelination, meningeal thickening, congestion, mononuclear cell infiltration, massive proliferation of cortical glial cells, and bacteria (>10(4) CFU/g) in the spinal cord and ganglia in mice. Furthermore, immunohistochemistry found that the heavily infiltrated glial cells were astrocytes. Strain 11313 harbored the resistance genes ant(6)-Ia, erm(B), optrA, tet(l), tet(o), and strain 11LB5 harbored the resistance genes ant(6)-Ia, erm(B), tet(40), tet(o/w/32/o), aac(6')-aph(2″). Mouse studies showed that strain 11LB5 exhibited a similar virulence to serotype 2 strain 700794, highlighting the need for surveillance of the other serotype S. suis isolates, in addition to serotype 2, in farms. This is the first report of the aminoglycoside resistance gene ant(6)-Ia in S. suis from animals. This suggests that S. suis might serve as an antibiotic resistance reservoir, which spreads the resistance gene ant(6)-Ia or optrA to other streptococcal pathogens on farms. | 2021 | 33669225 |
| 2085 | 10 | 0.8832 | Quinolone Resistance Genes qnr, aac(6')-Ib-cr, oqxAB, and qepA in Environmental Escherichia coli: Insights into Their Genetic Contexts from Comparative Genomics. Previous studies have reported the occurrence of transferable quinolone resistance determinants in environmental Escherichia coli. However, little is known about their vectors and genetic contexts. To gain insights into these genetic characteristics, we analyzed the complete genomes of 53 environmental E. coli isolates containing one or more transferable quinolone resistance determinants, including 20 sequenced in this study and 33 sourced from RefSeq. The studied genomes carried the following transferable quinolone resistance determinants alone or in combination: aac(6')-Ib-cr, oqxAB, qepA1, qnrA1, qnrB4, qnrB7, qnrB19, qnrD1, qnrS1, and qnrS2, with qnrS1 being predominant. These resistance genes were detected on plasmids of diverse replicon types; however, aac(6')-Ib-cr, qnrS1, and qnrS2 were also detected on the chromosome. The genetic contexts surrounding these genes included not only those found in clinical isolates but also novel contexts, such as qnrD1 embedded within a composite transposon-like structure bounded by Tn3-derived inverted-repeat miniature elements (TIMEs). This study provides deep insights into mobile genetic elements associated with transferable quinolone resistance determinants, highlighting the importance of genomic surveillance of antimicrobial-resistant bacteria in the environment. | 2025 | 39960660 |
| 2645 | 11 | 0.8831 | High prevalence of a gene cluster conferring resistance to streptomycin, sulfonamide, and tetracycline in Escherichia coli isolated from indigenous wild birds. A total of 116 Escherichia coli isolates from cecal contents of 81 indigenous wild birds in Korea were tested for antimicrobial susceptibility. Seventy-one isolates from sparrows (Passer montanus) and one isolate from doves (Columba livia) were resistant to three antimicrobials, including streptomycin, sulfonamide, and tetracycline (SSuT). PCR and subsequent sequence analysis revealed the SSuT gene cluster region (approximately 13 kb) harboring genes encoding resistance to streptomycin (strA and strB), sulfonamide (sul2), and tetracycline (tetB, tetC, tetD, and tetR). In particular, tetracycline resistance genes were located on the transposon Tn10-like element. The SSuT element-harboring E. coli can be an important source of the transmission of antimicrobial resistance to other pathogenic bacteria. Therefore, strict sanitary measures in human and animal environments are necessary to prevent the spread of resistant bacteria through fecal residues of wild birds. | 2021 | 33487603 |
| 8439 | 12 | 0.8829 | Comparative genomics analysis and virulence-related factors in novel Aliarcobacter faecis and Aliarcobacter lanthieri species identified as potential opportunistic pathogens. BACKGROUND: Emerging pathogenic bacteria are an increasing threat to public health. Two recently described species of the genus Aliarcobacter, A. faecis and A. lanthieri, isolated from human or livestock feces, are closely related to Aliarcobacter zoonotic pathogens (A. cryaerophilus, A. skirrowii, and A. butzleri). In this study, comparative genomics analysis was carried out to examine the virulence-related, including virulence, antibiotic, and toxin (VAT) factors in the reference strains of A. faecis and A. lanthieri that may enable them to become potentially opportunistic zoonotic pathogens. RESULTS: Our results showed that the genomes of the reference strains of both species have flagella genes (flaA, flaB, flgG, flhA, flhB, fliI, fliP, motA and cheY1) as motility and export apparatus, as well as genes encoding the Twin-arginine translocation (Tat) (tatA, tatB and tatC), type II (pulE and pulF) and III (fliF, fliN and ylqH) secretory pathways, allowing them to secrete proteins into the periplasm and host cells. Invasion and immune evasion genes (ciaB, iamA, mviN, pldA, irgA and fur2) are found in both species, while adherence genes (cadF and cj1349) are only found in A. lanthieri. Acid (clpB), heat (clpA and clpB), osmotic (mviN), and low-iron (irgA and fur2) stress resistance genes were observed in both species, although urease genes were not found in them. In addition, arcB, gyrA and gyrB were found in both species, mutations of which may mediate the resistance to quaternary ammonium compounds (QACs). Furthermore, 11 VAT genes including six virulence (cadF, ciaB, irgA, mviN, pldA, and tlyA), two antibiotic resistance [tet(O) and tet(W)] and three cytolethal distending toxin (cdtA, cdtB, and cdtC) genes were validated with the PCR assays. A. lanthieri tested positive for all 11 VAT genes. By contrast, A. faecis showed positive for ten genes except for cdtB because no PCR assay for this gene was available for this species. CONCLUSIONS: The identification of the virulence, antibiotic-resistance, and toxin genes in the genomes of A. faecis and A. lanthieri reference strains through comparative genomics analysis and PCR assays highlighted the potential zoonotic pathogenicity of these two species. However, it is necessary to extend this study to include more clinical and environmental strains to explore inter-species and strain-level genetic variations in virulence-related genes and assess their potential to be opportunistic pathogens for animals and humans. | 2022 | 35761183 |
| 3021 | 13 | 0.8828 | Sequencing and comparative analysis of IncP-1α antibiotic resistance plasmids reveal a highly conserved backbone and differences within accessory regions. Although IncP-1 plasmids are important for horizontal gene transfer among bacteria, in particular antibiotic resistance spread, so far only three plasmids from the subgroup IncP-1α have been completely sequenced. In this study we doubled this number. The three IncP-1α plasmids pB5, pB11 and pSP21 were isolated from bacteria of two different sewage treatment plants and sequenced by a combination of next-generation and capillary sequencing technologies. A comparative analysis including the previously analysed IncP-1α plasmids RK2, pTB11 and pBS228 revealed a highly conserved plasmid backbone (at least 99.9% DNA sequence identity) comprising 54 core genes. The accessory elements of the plasmid pB5 constitute a class 1 integron interrupting the parC gene and an IS6100 copy inserted into the integron. In addition, the tetracycline resistance genes tetAR and the ISTB11-like element are located between the klc operon and the trfA-ssb operon. Plasmid pB11 is loaded with a Tn5053-like mercury resistance transposon between the parCBA and parDE operons and contains tetAR that are identical to those identified in plasmid pB5 and the insertion sequence ISSP21. Plasmid pSP21 harbours an ISPa7 element in a Tn402 transposon including a class 1 integron between the partitioning genes parCBA and parDE. The IS-element ISSP21 (99.89% DNA sequence identity to ISSP21 from pB11), inserted downstream of the tetR gene and a copy of ISTB11 (identical to ISTB11 on pTB11) inserted between the genes pncA and pinR. On all three plasmids the accessory genes are almost always located between the backbone modules confirming the importance of the backbone functions for plasmid maintenance. The striking backbone conservation among the six completely sequenced IncP-1α plasmids is in contrast to the much higher diversity within the IncP-1β subgroup. | 2011 | 21115076 |
| 3008 | 14 | 0.8826 | Sequence of conjugative plasmid pIP1206 mediating resistance to aminoglycosides by 16S rRNA methylation and to hydrophilic fluoroquinolones by efflux. Self-transferable IncFI plasmid pIP1206, isolated from an Escherichia coli clinical isolate, carries two new resistance determinants: qepA, which confers resistance to hydrophylic fluoroquinolones by efflux, and rmtB, which specifies a 16S rRNA methylase conferring high-level aminoglycoside resistance. Analysis of the 168,113-bp sequence (51% G+C) revealed that pIP1206 was composed of several subregions separated by copies of insertion sequences. Of 151 open reading frames, 56 (37%) were also present in pRSB107, isolated from a bacterium in a sewage treatment plant. pIP1206 contained four replication regions (RepFIA, RepFIB, and two partial RepFII regions) and a transfer region 91% identical with that of pAPEC-O1-ColBM, a plasmid isolated from an avian pathogenic E. coli. A putative oriT region was found upstream from the transfer region. The antibiotic resistance genes tet(A), catA1, bla(TEM-1), rmtB, and qepA were clustered in a 33.5-kb fragment delineated by two IS26 elements that also carried a class 1 integron, including the sulI, qacEDelta1, aad4, and dfrA17 genes and Tn10, Tn21, and Tn3-like transposons. The plasmid also possessed a raffinose operon, an arginine deiminase pathway, a putative iron acquisition gene cluster, an S-methylmethionine metabolism operon, two virulence-associated genes, and a type I DNA restriction-modification (R-M) system. Three toxin/antitoxin systems and the R-M system ensured stabilization of the plasmid in the host bacteria. These data suggest that the mosaic structure of pIP1206 could have resulted from recombination between pRSB107 and a pAPEC-O1-ColBM-like plasmid, combined with structural rearrangements associated with acquisition of additional DNA by recombination and of mobile genetic elements by transposition. | 2008 | 18458128 |
| 2603 | 15 | 0.8825 | Characterization of antimicrobial resistance genes in Enterobacteriaceae carried by suburban mesocarnivores and locally owned and stray dogs. The role of wildlife in the dissemination of antimicrobial-resistant bacteria and antimicrobial resistance genes (ARGs) in the environment is of increasing concern. We investigated the occurrence, richness and transmissibility potential of ARGs detected in the faeces of three mesocarnivore species: the coyote (Canis latrans), raccoon (Procyon lotor) and Virginia opossum (Didelphis virginiana), and of stray and owned dogs in suburban Chicago, IL, USA. Rectal swabs were collected from live-captured coyotes (n = 32), raccoons (n = 31) and Virginia opossums (n = 22). Fresh faecal samples were collected from locally owned (n = 13) and stray dogs (n = 18) and from the live-captured mesocarnivores, when available. Faecal samples and rectal swabs were enriched to select for Enterobacteriaceae and pooled by mesocarnivore species and dog type (owned or stray). Pooled enriched samples were then analysed for the presence of ARGs using shotgun sequencing. The three mesocarnivore and stray dog samples had twice as many unique ARGs compared to the owned dog sample, which was partly driven by a greater richness of beta-lactamase genes (genes conferring resistance to penicillins and cephalosporins). Raccoon and stray dog samples had the most ARGs in common, suggesting possible exposure to similar environmental sources of ARGs. In addition to identifying clinically relevant ARGs (e.g. bla(CMY) and qnrB), some ARGs were linked to the class 1 integrase gene, intI1, which may indicate anthropogenic origin. Findings from this pilot investigation suggest that the microbial communities of suburban mesocarnivores and stray dogs can host ARGs that can confer resistance to several antimicrobials used in human and veterinary medicine. | 2020 | 32034890 |
| 3023 | 16 | 0.8824 | ICEAplChn1, a novel SXT/R391 integrative conjugative element (ICE), carrying multiple antibiotic resistance genes in Actinobacillus pleuropneumoniae. SXT/R391 integrative conjugative elements (ICEs) are capable of self-transfer by conjugation and highly prevalent in various aquatic bacteria and Proteus species. In the present study, a novel SXT/R391 ICE, named ICEAplChn1, was identified in the multidrug resistant (MDR) Actinobacillus pleuropneumoniae strain app6. ICEAplChn1 was composed of the typical SXT/R391 backbone and insertion DNA at eight hotspots, including HS1, HS2, HS3, HS4, HS5, VRII, VRIII and a new variation region VRVI. Many of the insertion contents were not present in other reported SXT/R391 family members, including ICEApl2, a recently identified SXT/R391 ICE from a clinical isolate of A. pleuropneumoniae. Remarkably, the VRIII region had accumulated seven resistance genes tet(A), erm(42), floR, aphA6, strB (two copies), strA and sul2. Of them, erm(42) and aphA6 emerged for the first time not only in the SXT/R391 elements but also in A. pleuropneumoniae. Phylogenetic analysis showed considerable variation of the backbone sequence of ICEAplChn1, as compared to those of other SXT/R391 ICEs. A circular intermediate form of ICEAplChn1 was detected by nested PCR. However, the conjugation experiments using different bacteria as recipients failed. These findings demonstrated that SXT/R391 ICEs are able to adapt to a broader range of host bacterial species. The presence of the MDR gene cluster in ICEAplChn1 underlines that SXT/R391 ICE could serve as an important vector for the accumulation of antibiotic resistance genes. | 2018 | 29885796 |
| 3036 | 17 | 0.8823 | Complete nucleotide sequences of 84.5- and 3.2-kb plasmids in the multi-antibiotic resistant Salmonella enterica serovar Typhimurium U302 strain G8430. The multi-antibiotic resistant (MR) Salmonella enterica serovar Typhimurium phage type U302 strain G8430 exhibits the penta-resistant ACSSuT-phenotype (ampicillin, chloramphenicol, streptomycin, sulfonamides and tetracycline), and is also resistant to carbenicillin, erythromycin, kanamycin, and gentamicin. Two plasmids, 3.2- and 84.5-kb in size, carrying antibiotic resistance genes were isolated from this strain, and the nucleotide sequences were determined and analyzed. The 3.2-kb plasmid, pU302S, belongs to the ColE1 family and carries the aph(3')-I gene (Kan(R)). The 84.5-kb plasmid, pU302L, is an F-like plasmid and contains 14 complete IS elements and multiple resistance genes including aac3, aph(3')-I, sulII, tetA/R, strA/B, bla(TEM-1), mph, and the mer operon. Sequence analyses of pU302L revealed extensive homology to various plasmids or transposons, including F, R100, pHCM1, pO157, and pCTX-M3 plasmids and TnSF1 transposon, in regions involved in plasmid replication/maintenance functions and/or in antibiotic resistance gene clusters. Though similar to the conjugative plasmids F and R100 in the plasmid replication regions, pU302L does not contain oriT and the tra genes necessary for conjugal transfer. This mosaic pattern of sequence similarities suggests that pU302L acquired the resistance genes from a variety of enteric bacteria and underscores the importance of a further understanding of horizontal gene transfer among the enteric bacteria. | 2007 | 16828159 |
| 1511 | 18 | 0.8823 | Characterization of an Extensively Drug-Resistant Salmonella Kentucky ST198 Co-Harboring cfr, mcr-1 and tet(A) Variant from Retail Chicken Meat in Shanghai, China. The emergence of extensively drug-resistant (XDR) foodborne pathogens poses grave threats to food safety. This study characterizes the genome of an XDR Salmonella Kentucky isolate (Sal23C1) co-harboring cfr, mcr-1 and tet(A) from Shanghai chicken meat in 2022, which was the only isolate co-harboring these three key resistance genes among 502 screened Salmonella isolates. Genomic analysis revealed that the multidrug resistance gene cfr, which confers resistance to phenicols, lincosamides, oxazolidinones, pleuromutilins and streptogramin A, was identified within a Tn3-IS6-cfr-IS6 structure on the transferable plasmid p3Sal23C1 (32,387 bp), showing high similarity to the Citrobacter braakii plasmid pCE32-2 (99% coverage, 99.98% identity). Concurrently, the mcr-1 gene resided in a pap2-mcr-1 structure on the transferable IncI2 plasmid p2Sal23C1 (63,103 bp). Notably, both genes could be co-transferred to recipient bacteria via conjugative plasmids at frequencies of (1.15 ± 0.98) × 10(-6). Furthermore, a novel ~79 kb multidrug resistance region (MRR) chromosomally inserted at the bcfH locus was identified, carrying fosA3, mph(A), rmtB, qnrS1 and bla(CTX-M-55). Additionally, a novel Salmonella Genomic Island 1 variant (SGI1-KI) harbored aadA7, qacEΔ1, sul1 and the tet(A) variant. The acquisition of these antibiotic resistance genes in this isolate enhanced bacterial resistance to 21 antimicrobials, including resistance to the critical last-resort antibiotics tigecycline and colistin, which left virtually no treatment options for potential infections. Taken together, this is the first comprehensive genomic report of an XDR poultry-derived Salmonella Kentucky isolate co-harboring cfr, mcr-1 and the tet(A) variant. The mobility of these resistance genes, facilitated by IS6 elements and conjugative plasmids, underscores significant public health risks associated with such isolates in the food chain. | 2025 | 40941142 |
| 2991 | 19 | 0.8822 | Occurrence and antimicrobial resistance of Salmonella species and potentially pathogenic Escherichia coli in free-living seals of Canadian Atlantic and eastern Arctic waters. Seal populations in Canadian waters provide sustenance to coastal communities. There is potential for pathogenic and/or antimicrobial-resistant bacteria to transfer to humans through inadvertent faecal contamination of seal products. The objective of this study was to investigate the occurrence and potential antimicrobial resistance of Salmonella spp., Escherichia coli and Listeria monocytogenes in faecal samples collected from grey seals (Halichoerus grypus) in the Gulf of St. Lawrence and from ringed seals (Pusa hispida) in Frobisher Bay and Eclipse Sound, Nunavut, Canada. Grey seals were harvested during commercial hunts or during scientific sampling; ringed seals were collected by Inuit hunters during subsistence harvests. Virulence genes defining pathogenic E. coli were identified by PCR, and antimicrobial susceptibility testing was performed on recovered isolates. In grey seals, E. coli was detected in 34/44 (77%) samples, and pathogenic E. coli (extraintestinal E. coli [ExPEC], enteropathogenic E. coli [EPEC] or ExPEC/EPEC) was detected in 13/44 (29%) samples. Non-susceptibility to beta-lactams and quinolones was observed in isolates from 18 grey seals. In ringed seals from Frobisher Bay, E. coli was detected in 4/45 (9%) samples; neither virulence genes nor antimicrobial resistance was detected in these isolates. In ringed seals from Eclipse Sound, E. coli was detected in 8/50 (16%) samples and pathogenic E. coli (ExPEC and ExPEC/EPEC) in 5/50 (10%) samples. One seal from Eclipse Sound had an E. coli isolate resistant to beta-lactams. A monophasic Salmonella Typhimurium was recovered from 8/50 (16%) seals from Eclipse Sound. All Salmonella isolates were resistant to ampicillin, streptomycin, sulfisoxazole and tetracycline. L. monocytogenes was not detected in any sample. These findings suggest that seals may act as important sentinel species and as reservoirs or vectors for antimicrobial-resistant and virulent E. coli and Salmonella species. Further characterization of these isolates would provide additional insights into the source and spread of antimicrobial resistance and virulence genes in these populations of free-living seals. | 2023 | 37317052 |