scholarly journals Novel Variants of AbaR Resistance Islands with a Common Backbone in Acinetobacter baumannii Isolates of European Clone II

2012 ◽  
Vol 56 (4) ◽  
pp. 1969-1973 ◽  
Author(s):  
Vaida Šeputienė ◽  
Justas Povilonis ◽  
Edita Sužiedėlienė

ABSTRACTIn this study, the genetic organization of three novel genomic antibiotic resistance islands (AbaRs) inAcinetobacter baumanniiisolates belonging to group of European clone II (EC II)comMintegrated sequences of 18-, 21-, and 23-kb resistance islands were determined. These resistance islands carry the backbone of AbaR-type transposon structures, which are composed of the transposition module coding for potential transposition proteins and other genes coding for the intact universal stress protein (uspA), sulfate permease (sul), and proteins of unknown function. The antibiotic resistance genesstrA,strB,tetB, andtetRand insertion sequence CR2 element were found to be inserted into the AbaR transposons. GenBank homology searches indicated that they are closely related to the AbaR sequences found integrated incomMin strains of EC II (A. baumanniistrains 1656-2 and TCDC-AB0715) and AbaR4 integrated in another location ofA. baumanniiAB0057 (EC I). All of the AbaRs showed structural similarity to the previously described AbaR4 island and share a 12,008-bp backbone. AbaRs contain Tn1213, Tn2006, and the multiple fragments which could be derived from transposons Tn3, Tn10, Tn21, Tn1000, Tn5393, and Tn6020, the insertion sequences IS26, ISAba1, ISAba14, and ISCR2, and the class 1 integron. Moreover, chromosomal DNA was inserted into distinct regions of the AbaR backbone. Sequence analysis suggested that the AbaR-type transposons have evolved through insertions, deletions, and homologous recombination. AbaR islands, sharing the core structure similar to AbaR4, appeared to be distributed in isolates of EC I and EC II via integration into distinct genomic sites, i.e.,phoandcomM, 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.


2011 ◽  
Vol 55 (7) ◽  
pp. 3201-3206 ◽  
Author(s):  
Lenka Krizova ◽  
Lenie Dijkshoorn ◽  
Alexandr Nemec

ABSTRACTTo assess the diversity of AbaR genomic resistance islands inAcinetobacter baumanniiEuropean clone I (MLST clonal complex 1), we investigated 26 multidrug-resistant strains of this major clone isolated from hospitals in 21 cities of 10 European countries between 1984 and 2005. Each strain harbored an AbaR structure integrated at the same position in the chromosomal ATPase gene. AbaR3, including four subtypes based on variations in class 1 integron cassettes, and AbaR10 were found in 15 and 2 strains, respectively, whereas a new, unique AbaR variant was discovered in each of the other 9 strains. These new variants, designated AbaR11 to AbaR19 (19.8 kb to 57.5 kb), seem to be truncated derivatives of AbaR3, likely resulting from the deletions of its internal parts mediated by either IS26elements (AbaR12 to AbaR19) or homologous recombination (AbaR11). AbaR3 was detected in all 10 strains isolated in 1984 to 1991, while AbaR11 to AbaR19 were carried only by strains isolated since 1997. Our results and those from previous publications suggest that AbaR3 is the original form of AbaR in European clone I, which may have provided strains of the lineage with a selective advantage facilitating their spread in European hospitals in the 1980s or before.


2001 ◽  
Vol 67 (12) ◽  
pp. 5675-5682 ◽  
Author(s):  
Anja S. Schmidt ◽  
Morten S. Bruun ◽  
Inger Dalsgaard ◽  
Jens L. Larsen

ABSTRACT A collection of 313 motile aeromonads isolated at Danish rainbow trout farms was analyzed to identify some of the genes involved in high levels of antimicrobial resistance found in a previous field trial (A. S. Schmidt, M. S. Bruun, I. Dalsgaard, K. Pedersen, and J. L. Larsen, Appl. Environ. Microbiol. 66:4908–4915, 2000), the predominant resistance phenotype (37%) being a combined oxytetracycline (OTC) and sulphadiazine/trimethoprim resistance. Combined sulphonamide/trimethoprim resistance (135 isolates) appeared closely related to the presence of a class 1 integron (141 strains). Among the isolates containing integrons, four different combinations of integrated resistance gene cassettes occurred, in all cases including a dihydrofolate reductase gene and a downstream aminoglycoside resistance insert (87 isolates) and occasionally an additional chloramphenicol resistance gene cassette (31 isolates). In addition, 23 isolates had “empty” integrons without inserted gene cassettes. As far as OTC resistance was concerned, only 66 (30%) out of 216 resistant aeromonads could be assigned to resistance determinant class A (19 isolates), D (n = 6), or E (n = 39); three isolates contained two tetracycline resistance determinants (AD, AE, and DE). Forty OTC-resistant isolates containing large plasmids were selected as donors in a conjugation assay, 27 of which also contained a class 1 integron. Out of 17 successful R-plasmid transfers to Escherichia coli recipients, the respective integrons were cotransferred along with the tetracycline resistance determinants in 15 matings. Transconjugants were predominantly tetApositive (10 of 17) and contained class 1 integrons with two or more inserted antibiotic resistance genes. While there appeared to be a positive correlation between conjugative R-plasmids andtetA among the OTC-resistant aeromonads, tetEand the unclassified OTC resistance genes as well as class 1 integrons were equally distributed among isolates with and without plasmids. These findings indicate the implication of other mechanisms of gene transfer besides plasmid transfer in the dissemination of antibiotic resistance among environmental motile aeromonads.


2020 ◽  
Author(s):  
Jorge Agramont ◽  
Sergio Gutierrez-Cortez ◽  
Enrique Joffré ◽  
Åsa Sjöling ◽  
Carla Calderon Toledo

AbstractWater and sediment samples affected by mining activities were collected from three lakes in Bolivia, the pristine Andean lake Pata Khota, the Milluni Chico lake directly impacted by acid mine drainage, and the Uru-Uru lake located close to Oruro city and highly polluted by mining activities and human wastewater discharges. Physicochemical parameters, including metal compositions, were analyzed in water and sediment samples. Antibiotic resistance genes (ARGs), were screened for, and verified by quantitative PCR together with the mobile element class 1 integron (intl1) as well as crAssphage, a marker of human fecal pollution. The gene intl1 showed a positive correlation with sul1, sul2, tetA and blaOXA-2. CrAssphage was only detected in Uru-Uru lake and its tributaries and significantly higher abundance of ARGs were found in these sites. Multivariate analysis showed that crAssphage abundance, electrical conductivity and pH were positively correlated with higher levels of intl1 and ARGs. Taken together our results suggest that fecal pollution is the major driver of higher ARGs and intl1 in wastewater and mining contaminated environments.


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.


2020 ◽  
Vol 29 (6) ◽  
pp. 580-587
Author(s):  
Balaram Khamari ◽  
Manmath Lama ◽  
Chanakya Pachi Pulusu ◽  
Amarendra Pratap  Biswal ◽  
Sai Manoz Lingamallu ◽  
...  

<b><i>Objectives:</i></b> The aim of the study was to determine the presence of antimicrobial-resistance (AMR) genes, virulence genes, and mobile genetic elements (MGEs) in 14 biofilm-producing clinical isolates of <i>Acinetobacter baumannii</i>. <b><i>Materials and Methods:</i></b> PCR amplification was performed to analyse the prevalence of genes associated with antibiotic resistance (extended-spectrum β-lactamases [ESBLs] and metallo-β-lactamases [MBLs]), virulence factors, MGEs (class 1 integron, Tn<i>1213</i>, and <i>A. baumannii</i> antibiotic resistance [AbaR]), and <i>comM</i> among the study isolates. Random amplified polymorphic DNA (RAPD) PCR was then deployed to understand their phylogenetic relationship. All the isolates were investigated for biofilm production. <b><i>Results:</i></b> Two isolates were antibiotic-sensitive (AS), 3 were multi-drug-resistant (MDR), and the remaining 9 were extensively drug-resistant (XDR). The majority of the isolates were found to be positive for biofilm production and were sensitive against tetracycline and colistin only. Ab14 and Ab11 were found to be resistant to minocycline and colistin, respectively. <i>bla</i><sub>TEM</sub>, <i>bla</i><sub>OXA</sub>, <i>bla</i><sub>NDM</sub>, <i>bla</i><sub>VIM</sub>, <i>bla</i><sub>SIM</sub>, and <i>bla</i><sub>PER-1</sub>; class 1 integron; composite transposon Tn<i>1213</i>; AbaR island, and virulence factor genes were detected among the isolates. These pathogens were found to have originated from multiple clonal lineages. <b><i>Conclusion:</i></b> Biofilm-producing <i>A. baumannii</i> with multiple virulence and AMR genes pose serious clinical challenges. The presence of MGEs further compounds the situation as these isolates serve as potential reservoirs of AMR and virulence genes. Together with their capacity for natural competence, <i>A. baumannii</i>, if left unchecked, will lead to the spread of resistance determinants to previously sensitive bacteria and may aid in the emergence of untreatable pan-drug-resistant phenotypes.


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