scholarly journals An Analysis of the Antibiotic Resistance Genes of Multi-Drug Resistant (MDR)Acinetobacter baumannii

2016 ◽  
Vol 48 (3) ◽  
pp. 217-224 ◽  
Author(s):  
Jina Lim ◽  
Gyusang Lee ◽  
Yeonim Choi ◽  
Jongbae Kim
2020 ◽  
Vol 76 (1) ◽  
pp. 65-69
Author(s):  
Xiaoting Hua ◽  
Robert A Moran ◽  
Qingye Xu ◽  
Jintao He ◽  
Youhong Fang ◽  
...  

Abstract Objectives To reconstruct the evolutionary history of the clinical Acinetobacter baumannii XH1056, which lacks the Oxford scheme allele gdhB. Methods Susceptibility testing was performed using broth microdilution and agar dilution. The whole-genome sequence of XH1056 was determined using the Illumina and Oxford Nanopore platforms. MLST was performed using the Pasteur scheme and the Oxford scheme. Antibiotic resistance genes were identified using ABRicate. Results XH1056 was resistant to all antibiotics tested, apart from colistin, tigecycline and eravacycline. MLST using the Pasteur scheme assigned XH1056 to ST256. However, XH1056 could not be typed with the Oxford MLST scheme as gdhB is not present. Comparative analyses revealed that XH1056 contains a 52 933 bp region acquired from a global clone 2 (GC2) isolate, but is otherwise closely related to the ST23 A. baumannii XH858. The acquired region in XH1056 also contains a 34 932 bp resistance island that resembles AbGRI3 and contains the armA, msrE-mphE, sul1, blaPER-1, aadA1, cmlA1, aadA2, blaCARB-2 and ere(B) resistance genes. Comparison of the XH1056 chromosome to that of GC2 isolate XH859 revealed that the island in XH1056 is in the same chromosomal region as that in XH859. As this island is not in the standard AbGRI3 position, it was named AbGRI5. Conclusions XH1056 is a hybrid isolate generated by the acquisition of a chromosomal segment from a GC2 isolate that contains a resistance island in a new location—AbGRI5. As well as generating ST256, it appears likely that a single recombination event is also responsible for the acquisition of AbGRI5 and its associated antibiotic resistance genes.


2019 ◽  
Vol 74 (6) ◽  
pp. 1484-1493 ◽  
Author(s):  
Happiness H Kumburu ◽  
Tolbert Sonda ◽  
Marco van Zwetselaar ◽  
Pimlapas Leekitcharoenphon ◽  
Oksana Lukjancenko ◽  
...  

2021 ◽  
Vol 31 (4) ◽  
pp. 51-60
Author(s):  
Vu Nhi Ha ◽  
Kieu Chi Thanh ◽  
Nguyen Thai Son ◽  
Dao Van Thang ◽  
Tran Huy Hoang

Acinetobacter baumannii (A. baumannii) is currently ranked as the frst concern for the development of new antibiotics due to its capacity of resistance to all available families of antibiotics. The most common mechanism of antibiotic resistance development in A. baumannii is through the acquisition of mobile genetic elements such as plasmid, transposon and integrons carrying resistance genes. A. baumannii strain TN81 was isolated from sputum specimen of a 45-year-old man at Thanh Nhan Hospital (Hanoi, Vietnam) and confrmed to be a multidrug resistance strain with high minimum inhibitory concentration value of 8/9 type of antibiotics, especially colistin. De novo assembly of the whole genome shotgun sequence of strain TN81 yielded an estimated genome size of 3,739,193 bp with 593 contigs and N50 is 9,126 bp. MLST analysis showed that TN81 belongs to ST164, which was frst reported as genome assembly in Vietnam. Resistance genes identifcation through database found that TN81 contained 12 genes encoding for antibiotic resistance. Notably, we performed de novo assembly of plasmid through short read sequence and identifed two potential plasmid-encoded antibiotic resistance genes (ant(2’’)-Ia / aadB and tet (39), which were reported for the first time as in ST164 group. This study aimed to investigate the plasmid-containing antibiotic resistance genes from a nosocomial isolate of Acinetobacter baumannii. Conclusively, all of these results would be crucial information on antibiotic resistance in A. baumannii in Vietnam.


2011 ◽  
Vol 60 (2) ◽  
pp. 211-215 ◽  
Author(s):  
B. S. Lopes ◽  
A. Hamouda ◽  
J. Findlay ◽  
S. G. B. Amyes

Acinetobacter baumannii is a Gram-negative pathogenic bacterium that often exhibits a multidrug-resistant phenotype causing infections at various sites of the body and increasingly leading to septicaemic shock. This study evaluated the role of acriflavine, a frameshift mutagen, on the movement of insertion sequence ISAba1 in clinical isolates of A. baumannii, with the focus on changes in expression levels of the bla ADC and bla OXA-51-like genes. Resistance profiles were assessed with consideration of ISAba1 acting as a promoter upstream of the bla ADC or bla OXA-51-like gene. ISAba1 movement was observed in the acriflavine mutants Ab153M and Ab1225M. Ab153M exhibited an increase in the MIC values of carbapenems and ceftazidime, with ISAba1 gained upstream of the bla ADC and bla OXA-51-like genes, correlating with an increase in gene expression. Reduced expression of the 17, 23 and 25 kDa outer-membrane proteins (OMPs) was also observed in Ab153M. There was a significant decrease in MIC values of carbapenems with the loss of ISAba1 upstream of the bla ADC and bla OXA-51-like genes in strain Ab1225M, and a significant decrease in bla OXA-51-like gene expression and, to a lesser extent, in bla ADC expression. Ab1225M and a serially subcultured Ab1225 strain (Ab1225s) exhibited overexpression of the 17, 23, 25 and 27 kDa OMPs. There was a decrease in MIC values of the carbapenems and piperacillin/tazobactam but not of ceftazidime in Ab1225s, which had ISAba1 upstream of the bla ADC and bla OXA-51-like genes. A significant decrease in bla OXA-51-like expression was observed in Ab1225s, whereas the expression of bla ADC was similar to that in the Ab1225 parental strain. The attenuation in this strain may be due to overexpression of OMPs and it is clear that, even if ISAba1 is present upstream of an antibiotic resistance gene, it may not necessarily contribute towards the overexpression of antibiotic resistance genes (bla OXA-51-like in Ab1225s). Movement of the IS element within the A. baumannii chromosome may be an important regulatory mechanism employed by the bacterium under particular stress conditions, and the ability to upregulate the expression of antibiotic resistance genes is likely to be an important factor in the pathogenicity of this bacterium.


2009 ◽  
Vol 54 (1) ◽  
pp. 333-340 ◽  
Author(s):  
Sébastien Coyne ◽  
Ghislaine Guigon ◽  
Patrice Courvalin ◽  
Bruno Périchon

ABSTRACT An oligonucleotide-based DNA microarray was developed to evaluate expression of genes for efflux pumps in Acinetobacter baumannii and to detect acquired antibiotic resistance determinants. The microarray contained probes for 205 genes, including those for 47 efflux systems, 55 resistance determinants, and 35 housekeeping genes. The microarray was validated by comparative analysis of mutants overexpressing or deficient in the pumps relative to the parental strain. The performance of the microarray was also evaluated using in vitro single-step mutants obtained on various antibiotics. Overexpression, confirmed by quantitative reverse transcriptase PCR, of RND efflux pumps AdeABC, due to a G30D substitution in AdeS in a multidrug-resistant (MDR) strain obtained on gentamicin, and AdeIJK, in two mutants obtained on cefotaxime or tetracycline, was detected. A new efflux pump, AdeFGH, was found to be overexpressed in a mutant obtained on chloramphenicol. Study of MDR clinical isolates, including the AYE strain, whose entire sequence has been determined, indicated overexpression of AdeABC and of the chromosomally encoded cephalosporinase as well as the presence of several acquired resistance genes. The overexpressed and acquired determinants detected by the microarray could account for nearly the entire MDR phenotype of the isolates. The microarray is potentially useful for detection of resistance in A. baumannii and should allow detection of new efflux systems associated with antibiotic resistance.


2016 ◽  
Vol 60 (3) ◽  
pp. 1801-1818 ◽  
Author(s):  
Nabil Karah ◽  
Chinmay Kumar Dwibedi ◽  
Karin Sjöström ◽  
Petra Edquist ◽  
Anders Johansson ◽  
...  

Acinetobacter baumanniihas emerged as an important opportunistic pathogen equipped with a growing number of antibiotic resistance genes. Our study investigated the molecular epidemiology and antibiotic resistance features of 28 consecutive carbapenem-resistant clinical isolates ofA. baumanniicollected throughout Sweden in 2012 and 2013. The isolates mainly belonged to clonal complexes (CCs) with an extensive international distribution, such as CC2 (n= 16) and CC25 (n= 7). Resistance to carbapenems was related toblaOXA-23(20 isolates),blaOXA-24/40-like(6 isolates),blaOXA-467(1 isolate), and ISAba1-blaOXA-69(1 isolate). Ceftazidime resistance was associated withblaPER-7in the CC25 isolates. Two classical point mutations were responsible for resistance to quinolones in all the isolates. Isolates with high levels of resistance to aminoglycosides carried the 16S rRNA methylasearmAgene. The isolates also carried a variety of genes encoding aminoglycoside-modifying enzymes. Several novel structures involved in aminoglycoside resistance were identified, including Tn6279, ΔTn6279, Ab-ST3-aadB, and different assemblies of Tn6020and TnaphA6. Importantly, a number of circular forms related to the IS26or ISAba125composite transposons were detected. The frequent occurrence of these circular forms in the populations of several isolates indicates a potential role of these circular forms in the dissemination of antibiotic resistance genes.


2020 ◽  
Author(s):  
Dickson Aruhomukama ◽  
Ivan Sserwadda ◽  
Gerald Mboowa

AbstractIn recent times, pan-drug resistant Acinetobacter baumannii have emerged and continue to spread among critically ill patients, this poses an urgent risk to global and local human health. This study sought to provide the first genomic analysis of a pan-drug resistant Acinetobacter baumannii from Uganda and Africa, and to tell a story of mobile genetic element-mediated antibiotic resistance evolution in the isolate. It was an in-silico study in which intrinsic and acquired antibiotic resistance genes, and/or chromosomal resistance mutations were identified using PATRIC, CARD, NDARO and ResFinder. Screening for insertion sequences was done using ISfinder. Also, plasmid screening, phylogenetic analysis and sequence typing were performed using PlasmidFinder, PATRIC and Gubbin, and MLST respectively.The isolate belonged to the Sequence type 136, belonging to Clonal complex 208 and Global complex 2. This isolate shared close homology with strains from Tanzania. Resistance in the isolate was chromosomally and mobile genetic element-mediated by Acinetobacter-derived cephalosporinases and carbapenem hydrolyzing class D β-lactamses, blaOXA-2, 51, 5 88, 317, blaADC-2, 25. Colistin resistance was associated with previously documented mutants, lpxA and lpxC. Other key resistance genes identified were: aph(3”)-lb, aph(6)-ld, aph(3’)-la, aac(3)-lld, aac(3)-lla, aph(3’)-l, aph(3”)-l, aph(6)-lc, aph(6)-ld, aac(3)-II, III, IV, VI, VIII, IX, X, macA, macB, tetA, tetB, tetR, dfrA, and those of the floR family. RSF1010 like IncQ broad-host-range plasmids and features of pACICU1, pACICU2, and p3ABAYE Acinetobacter baumannii plasmids namely partitioning proteins ParA and B were present. Insertion sequences present included IS3, IS5, IS66 and those of the ISLre2 families.The study described for the first time a pan-drug resistant Acinetobacter baumannii from Uganda, and told a story of mobile genetic element-mediated antibiotic resistance evolution in the isolate despite being limited by pan-drug resistance phenotypic data. It provides a basis to track trends in antibiotic resistance and identification of emerging resistance patterns in Acinetobacter baumannii in Uganda.


Antibiotics ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1362
Author(s):  
Hlengiwe N. Mtetwa ◽  
Isaac D. Amoah ◽  
Sheena Kumari ◽  
Faizal Bux ◽  
Poovendhree Reddy

Essential components of public health include strengthening the surveillance of infectious diseases and developing early detection and prevention policies. This is particularly important for drug-resistant tuberculosis (DR-TB), which can be explored by using wastewater-based surveillance. This study aimed to use molecular techniques to determine the occurrence and concentration of antibiotic-resistance genes (ARGs) associated with tuberculosis (TB) resistance in untreated and treated wastewater. Raw/untreated and treated (post-chlorination) wastewater samples were taken from three wastewater treatment plants (WWTPs) in South Africa. The ARGs were selected to target drugs used for first- and second-line TB treatment. Both conventional polymerase chain reaction (PCR) and the more advanced droplet digital PCR (ddPCR) were evaluated as surveillance strategies to determine the distribution and concentration of the selected ARGs. The most abundant ARG in the untreated wastewater was the rrs gene, associated with resistance to the aminoglycosides, specifically streptomycin, with median concentration ranges of 4.69–5.19 log copies/mL. In contrast, pncA gene, associated with resistance to the TB drug pyrazinamide, was the least detected (1.59 to 2.27 log copies/mL). Resistance genes associated with bedaquiline was detected, which is a significant finding because this is a new drug introduced in South Africa for the treatment of multi-drug resistant TB. This study, therefore, establishes the potential of molecular surveillance of wastewater for monitoring antibiotic resistance to TB treatment in communities.


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