Investigation of transposons,insertion sequences and integron in multidrug-resistant acinetobacter baumannii
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OBJECTIVE To investigate the distribution of genetic markers of mobile genetic elements: transposons,insertion sequences and integron in multidrug-resistant Acinetobacter baumannii.METHODS From Jan to Dec 2008,20 strains of multidrug-resistant A.baumannii isolated from sputum were collected from a hospital of a county-level city.Then,5 kinds of genetic markers of mobile genetic elements(tnpU,tnp513,IS26,ISaba1,intⅠ1) were analyzed by PCR.RESULTS All 5 kinds of genetic markers of mobile genetic elements were detected,and 15 strains(75.0%),15 strains(75.0%),18 strains(90.0%),17 strains(85.0%),15 strains(75.0%)were detected to carry tnpU,tnp513,IS26,ISaba1,intⅠ1,respectively.CONCLUSION The high rate of drug resitance of MDR-ABA to beta-lactams,aminoglycosides,quinolones is associated to 5 kinds of genetic markers of mobile genetic elements detected in 20 strains of multidrug-resistant A.baumannii.Keywords:
Acinetobacter baumannii
Insertion sequence
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Objective To investigate the distribution of the mobile genetic elements,including integrons,transposons,insertion sequences and conjugative plasmids,in Acinetobacter baumannii carried with bla ADC gene. Methods One hundred and seventy-nine isolates of Acinetobacter baumannii were collected,and their bla ADC gene was determined by PCR. Then,four kinds of mobile genetic elements,including integron genetic marks such as intI 1,intI 2,intI 3 and qacE △1-sul1,transposon genetic marks such as merA,tnpU,tnp513 and tnpA,insertion sequence genetic marks such as ISAba1 and IS26,and conjunction plasmid genetic marks such as traA and trbC,and the antimicrobial susceptibility of the isolates with bla ADC gene were detected by PCR and the disk diffusion method,respectively. Results There was 117 isolates of Acinetobacter baumannii carried with bla ADC gene in all 179 isolates. Among them,the positive rates of intI 1,qacE△1-sul1,merA,tnpU,tnp513,ISAba1 and IS26 were 71. 8%,98. 3%,94. 9%,93. 2%,76. 9%,98. 3% and 100. 0%,respectively,and the other 5 genes were negative. There were at least 3 and at most 7 mobile genetic marks to be detected for each of 117 isolates,and the isolates with 3 and 7 mobile genetic marks accounted for 0. 9% and 50. 4%,respectively.Conclusion Mobile genetic elements can be easily detected from the Acinetobacter baumannii carried with bla ADC,and its drug resistance may be related to the existence of mobile genetic elements.
Acinetobacter baumannii
Insertion sequence
Genetic Analysis
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Objective: To investigate the distribution and prevalence of integrase gene of multidrug-resistance Acinetobacter baumannii in Tianjin,and to analyze the relationship between integron and multidrug-resisitance of Acinetobacter baumannii.Methods: Fifty-five multidrug- resistance Acinetobacter baumannii were collected from three hospitals in Tianjin.The drug sensitivation was detected by K-B test.The integrase genes were detected by PCR.The relationship of clinical isolates was analysed by multigene cluster typing.Results: There were 47 strains ofⅠclass integrase genes,23 contained variable regions,but noⅡand Ⅲ class integrase gene in 55 multidrug- resistance Acinetobacter baumannii.The main reason caused aminoglycosides resistance was the aacA4 and aadA1 cassette in the variable region.Three clone strains were found in 55 multidrug-resistance Acinetobacter baumannii by multigene cluster typing.Conclusion: It was found thatⅠclass integrase gene was existed extensively in multidrug- resistance Acinetobacter baumannii in Tianjin.All strains could be typed by multigene cluster typing.
Acinetobacter baumannii
Gene cassette
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Infections and outbreaks caused by multidrug-resistant Acinetobacter baumannii (MDR-AB) are prevalent and have been reported worldwide over the past 20 or more years. Class 1 integron in MDR-AB plays an important role in the spread of antibiotic resistance in clinical settings. This study has been conducted to evaluate the detection of metallo-β-lactamase, characterization of class 1 integron and determination of clonal relatedness among A. baumannii hospital isolates. Sixty-five clinical isolates of MDR-AB were recovered from two Iranian hospital's intensive care units from February to August 2013. Integrase (intI1) and bla IMP genes were detected in 70.8 % (n=46/65) and 9.23 % (n=6/65) of the isolates using PCR assay, respectively. No other metallo-β-lactamase genes (bla VIM, bla SIM and bla NDM) were detected. PCR sequencing of integron gene cassette revealed the following arrays: bla OXA10-aacA4-bla IMP-55-cmlA5 (as a novel array was designated In1243), aacC1 and aadA1. Analysis of bla IMP gene revealed a new allele designated as bla IMP-55. Gene transfer experiment by conjugation showed the 36 kb conjugative plasmid harbouring In1243. The clonal assessment by repetitive extragenic palindromic PCR demonstrated a high-degree relatedness among the strains, but strains harbouring In1243 displayed a different repetitive extragenic palindromic PCR profile. In this study, we found that a novel class 1 integron (In1243) that encoded a new bla IMP allele resided on a transferable plasmid in non-clonal strains of MDR-AB.
Acinetobacter baumannii
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To characterize the class I integron in Acinetobacter baumannii and to analyze the correlation between integron and drug resistance.In total 187 strains were collected between 2008 and 2009. All strains were tested by Kirb-Bauer disk diffusion test for drug resistance. PCR and DNA sequencing were used to detected class I integrase gene and to clarify the context of gene cassette.Class I integrase gene was detected in 100 (53.4%) of the isolates analyzed. Seven different gene cassettes were identified, including a new integron (GenBank: HQ322622) carrying an unknown protein probably associated with recombination. The vast majority of the cassettes encoded amonoglycoside resistance gene, including aacA4, aadA1, aacC1, aac6 II , aadA2. Susceptibility data show that strains carrying class I integron were significantly more resistant to all of the antibiotics tested than isolates lacking class I integron. The correlation between the presence of integron and the multidrug-resistance of A. baumannii was statistically significant.Drug resistance genes integrated by Class I integron were widespread in A. baumannii. Class I integron plays an important role in resistance of A. baumannii.
Acinetobacter baumannii
Gene cassette
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OBJECTIVE To study the existence status of class Ⅰ integron and transposable element of multi-resistant Acinetobactor baumannii isolated form ICU of Yinzhou People′s Hospital in Ningbo. METHODS The samples of 20 A.baumannii isolates were collected from Oct 2007 to Jul 2008.The susceptibility to 32 antibiotics of the isolates was measured.The genetic markers of integron qacE△1-sul1 and transposable element tnpU were analyzed by polymerase chain reaction(PCR).The PCR products of tnpU or qacE△1-sul1 were sequenced for determination. RESULTS In the 20 ABA isolates,the positive rate of class Ⅰ integron qacE△1-sull was 75%,and the positive rate of transposable element tnpU was 55.0%. CONCLUSIONS The positive rate of the integron qacE△1-sul1 and transposable element tnpU for multi-resistant A.baumannii is high in Yinzhou People′s Hospital in Ningbo.It should be reevaluated the preventative role of chlorhexidine for operation.
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OBJECTIVE To understand the distribution of genetic markers of transposons and insertion sequences in multidrug-resistant Acinetobacter baumannii(A.baumannii) isolated from this hospital.METHODS From Mar,2008 to Nov,2008,20 strains of multidrug-resistant A.baumannii were isolated from the clinical specimens.Then,genetic markers of transposons and insertion sequences: tnpU,tnp513,ISaba1,and linkage detection of ISaba1-ADC were analyzed by PCR.RESULTS In 20 strains of multidrug-resistant A.baumannii,there were 15 strains tested with tnpU and 15 strains tested with tnp513,both of the detection rates were 75.0%.There were 17 strains tested with ISaba1,with the detection rate of 85.0%,and there were 17 strains with the linkage detection of ISaba1-ADC,with the detection rate of 85.0%.CONCLUSION The group of the multidrug-resistant A.baumannii showed multidrug-resistance to the β-lactam antibiotics and aminoglycoside antibiotics,which may be related to the transposons and insertion sequences.
Acinetobacter baumannii
Insertion sequence
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A total of 46 carbapenem- and multidrug-resistant (CR- and MDR-)Acinetobacter baumannii bacteremic isolates from a Taiwanese medical center were investigated over the period 2000 to 2006 using randomly amplified polymorphic DNA (RAPD) profiling and by analysing the genetic organization of their integrons. The results of RAPD patterns revealed that before 2003 each CR- and MDR-A. baumannii bacteremic isolate was independent, but after 2003 the isolates appeared to belong in four epidemic strains and persisted in the hospital. All the CR- and MDR-A. baumannii strains harbored class I integron (intI1) genes. PCR amplification and nucleotide sequencing showed that the cassette genes of intI1 were found to form four different antibiotic-resistant gene alignments in those strains. The bla(IMP-1) gene in the cassette genes of intI1 was identified in a clone, which raised great concern that clonal spread of this strain or of an integron-mediated horizontal gene may have occurred.
Acinetobacter baumannii
Gene cassette
Carbapenem
clone (Java method)
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OBJECTIVE To analyze the existence state of drug-resistant gene,integron and Tn21/Tn501 transposon and the relationship of Acinetobacter baumannii in Ningbo No.2 Hospital by genetic mark.METHODS Twenty seven strains of A.baumannii were clinically isolated.Drug-resistant gene,integron,and Tn21/Tn501 transposon were analyzed using polymerase chain reaction(PCR).The relationship was analyzed with cluster analysis methods.RESULTS The positive rates of blaTEM,blaOXA-23 cluster,blaADC,aac(3)-Ⅰ,aac(6′)-Ⅰ,ant(3″)-Ⅰ,qacE△1-sulⅠ,and intⅠ1 were 81.5%,44.4%,85.2%,85.2%,66.7%,81.5%,85.2%,and 85.2%,respectively.The others were negative.The result of multi-gene cluster analysis showed that the clone transmission existed.CONCLUSIONS The clone transmission of A.baumannii exists in Ningbo No.2 Hospital.The outbreak of A.baumannii may be possible because there are more than 3 clone transmission strains.
Acinetobacter baumannii
clone (Java method)
Gene cluster
Genetic Analysis
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Objective:To study the existence status of the integron and transposable element of multi-resistant Acinetobactor baumannii isolates in clinic in Nanjing.Methods:The samples of 20 multi-resistant acinetobacter baumannii isolates were collected from Jul,2007 to Oct,2007 of patients in hospitals of Nanjing.To determine the sensitivity to the 11 antibacterial a broth induction method was used,the genetic marker of integron qacE△1-sul1 and transposable element tnpU were analyzed by polymerase chain reaction(PCR).Results:In the 20 AB isolates,the rate of the positive of integron qacE△1-sull is 70%,and the rate of transposable element tnpU is 65%.Conclusion:The positive rate of the integron qacE△1-sul1 and transposable element tnpU for multi-resistant acinetobactor baumannii is high in Nanjing region.It should be reevaluated the chlorhexidine used as precaution infection drug after operation.
Acinetobacter baumannii
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Objective:To study the distribution and structure of gene cassettes of class I integron in Acinetobacter baumannii in the First Affiliated Hospital of NJMU and explore the relationship between integron and its resistance.Methods:K-B tests were performed to detect the susceptibility of 77 isolates of Acinetobacter Baumannii randomly selected from the hospital to 18 kinds of antimicrobial agents,class 1 integrase gene(intI 1) and its variable region were amplificated by PCR,the products were analyzed by restriction endonucleases and sequenced.Results:77 isolates from different samples were serious antibiotic resistance.49 of 77(63.64%) isolates were found containing class 1 integron and 91.84%(45 / 49) of the intI 1 positive strains owned the variable region.Four different sizes(0.8 kb,1.8 kb,2.3 kb and 3.0 kb) of the variable region of integrons were amplified.Sequencing results identified four gene cassettes arrays:aacA4,dfrXII-orfF-aadA2,aacA4-catB8-aadA1 and aacC1-orfX-orfX-orfX'-aadA1a.Significant association was demonstrated between integron carriage and resistance to antibiotics in Acinetobacter baumannii.Conclusion:class I integron is closely related to the resistance of Acinetobacter baumannii and plays an important role in its multi-drug resistance.
Acinetobacter baumannii
Gene cassette
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