Aminoglycoside resistance in multiply antibiotic-resistant Acinetobacter baumannii belonging to global clone 2 from Australian hospitals

Nigro, Steven J.; Post, Virginia; Hall, Ruth M.

doi:10.1093/jac/dkr163

Cited by 93 publications

(93 citation statements)

References 29 publications

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“…1B). ARI R16a is composed of the IS26-based compound transposon Tn6020 (34) and three different Tn3-family members, i.e., Tn1 (35), Tn5393 (36), and the newly identified Tn6333. All resistance genes of ARI R16a are located in transposons Tn1 (bla TEM-1D ), Tn6020 (aphA1b), and Tn6333 (mer module).…”

Section: Resultsmentioning

confidence: 99%

Characterization of Two Multidrug-Resistant IncA/C Plasmids from the 1960s by Using the MinION Sequencer Device

Szabó

Nagy

Wilk

et al. 2016

Antimicrob Agents Chemother

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Two A/C incompatibility group (IncA/C family) plasmids from the 1960s have been sequenced and classified into the A/C 2 type 1 group. R16a and IP40a contain novel antibiotic resistance islands and a complete GIsul2 genomic island not previously found in the family. In the 173.1-kb R16a, the 29.9-kb antibiotic resistance island (ARI) is located in a unique backbone position not utilized by ARIs. ARI R16a consists of Tn1, Tn6020, and Tn6333, harboring the resistance genes bla TEM-1D and aphA1b and a mer module, respectively; a truncated Tn5393 copy; and a gene cluster with unknown function. Plasmid IP40a is 170.4 kb in size and contains a 5.6-kb ARI inserted into the kfrA gene. ARI IP40a carrying bla TEM-1D and aphA1b genes is composed of Tn1 with a Tn6023 insertion. Additionally, IP40a harbors single IS2, IS186, and Tn1000 insertions scattered in the backbone; an IS150 copy in GIsul2; and a complete Tn6333 carrying a mer module at the position of ARI R16a . Loss of resistance markers in R16a, IP40a, and R55 was observed during stability tests. Every phenotypic change proved to be the result of recombination events involving mobile elements. Intramolecular transposition of IS copies that generated IP40a derivatives lacking large parts of the backbone could account for the formation of other family members, too. The MinION platform proved to be a valuable tool in bacterial genome sequencing since it generates long reads that span repetitive elements and facilitates full-length plasmid or chromosome assembly. Nanopore technology enables rapid characterization of large, low-copy-number plasmids and their rearrangement products.

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Section: Resultsmentioning

confidence: 99%

Characterization of Two Multidrug-Resistant IncA/C Plasmids from the 1960s by Using the MinION Sequencer Device

Szabó

Nagy

Wilk

et al. 2016

Antimicrob Agents Chemother

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“…Due to A. baumannii's ability to acquire drug resistance determinants, it was not surprising that the vast majority of isolates tested harbored multiple resistance determinants; nine isolates had 13 detected resistance genes in addition to positive con-trols. In fact, various isolates were found to contain up to four ␤-lactamase determinants and six AG resistance determinants; the prevalence of multiple AG resistance determinants in particular has been well documented (47)(48)(49).…”

Section: Discussionmentioning

confidence: 99%

Antimicrobial Resistance Determinants in Acinetobacter baumannii Isolates Taken from Military Treatment Facilities

Taitt

Łęski

Stockelman

et al. 2014

Antimicrob Agents Chemother

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c Multidrug-resistant (MDR) Acinetobacter baumannii infections are of particular concern within medical treatment facilities, yet the gene assemblages that give rise to this phenotype remain poorly characterized. In this study, we tested 97 clinical A. baumannii isolates collected from military treatment facilities (MTFs) from 2003 to 2009 by using a molecular epidemiological approach that enabled for the simultaneous screening of 236 antimicrobial resistance genes. Overall, 80% of the isolates were found to be MDR, each strain harbored between one and 17 resistant determinants, and a total of 52 unique resistance determinants or gene families were detected which are known to confer resistance to ␤-lactam (e.g., bla GES-11 , bla TEM , bla OXA-58 ), aminoglycoside (e.g., aphA1, aacC1, armA), macrolide (msrA, msrB), tetracycline [e.g., tet(A), tet(B), tet(39)], phenicol (e.g., cmlA4, catA1, cat4), quaternary amine (qacE, qacE⌬1), streptothricin (sat2), sulfonamide (sul1, sul2), and diaminopyrimidine (dfrA1, dfrA7, dfrA19) antimicrobial compounds. Importantly, 91% of the isolates harbored bla OXA-51-like carbapenemase genes (including six new variants), 40% harbored the bla OXA-23 carbapenemase gene, and 89% contained a variety of aminoglycoside resistance determinants with up to six unique determinants identified per strain. Many of the resistance determinants were found in potentially mobile gene cassettes; 45% and 7% of the isolates contained class 1 and class 2 integrons, respectively. Combined, the results demonstrate a facile approach that supports a more complete understanding of the genetic underpinnings of antimicrobial resistance to better assess the load, transmission, and evolution of MDR in MTF-associated A. baumannii.

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“…The fast development and worldwide dissemination of A. baumannii as a major nosocomial pathogen is significant and shows its successful adaptation to the 21st century hospital wards (7). The 2 main mechanisms of resistance to aminoglycosides are as follow: first, changes in the structure of the ribosome as a result of the structural protein mutant ribosomes, rRNA or enzymatically; and the second, changes in the structure of antibiotics by enzymes (8) most common mechanism of resistance to aminoglycosides in this bacterium is the modification of hydroxyl or amino groups of the antibiotic by modifying aminoglycoside (9,10), albeit other mechanisms such as reduced permeability and change of the binding sites have been suggested (11). Aminoglycosides have long been used for the therapy of infection in hospitalized patients and still are an essential option for treatment of diseases created by MDR strains.…”

Section: Introductionmentioning

confidence: 99%

Distribution of Aminoglycoside Resistance Genes Among Acinetobacter Baumannii Strains Isolated From Burn Patients in Tehran, Iran

Khoshnood

Eslami

Hashemi

et al. 2017

Arch Pediatr Infect Dis

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Background: Acinetobacter baumannii is an important cause of nosocomial infections, particularly in burn patients. Hospital Infections caused by these bacteria are difficult to treat. Objectives: The present study aimed at determining the frequency of genes encoding aminoglycoside-modifying enzymes in A. baumannii strains isolated from burn patients in Shahid Motahari hospital. Methods: This study was performed on 100 A. baumannii strains collected from Shahid Motahari hospital in Tehran during 2013 and 2014. The bacteria were cultured and identified. Antibiotic susceptibility testing was performed by disk diffusion method according to the CLSI guidelines. PCR assay was done to find the genes encoding aminoglycoside-modifying enzymes. Results: In this study, highest resistance to antibiotic was reported for ceftriaxone, ciprofloxacin, and ceftizoxime (100%), whereas the highest susceptibility was observed for colistin (100%), followed by gentamicin, amikacin, and tobramycin with (93%), (90%), and (87%), respectively. In the total of 100 strains studied, aphA6, aadB, aacC1 and aadA1 genes were found in 657 221 and 37 of A. baumannii isolates, respectively; 8 isolates had aadB and aphA6 genes and 3 had aadB, aadA1, aacC1, and aphA6 genes. Conclusions: This study showed the high frequency aminoglycoside-resistance genes among A. baumanni strains. Thus, the implementation of appropriate programs to prevent the spread of the bacteria seems necessary in the Shahid Motahari hospital.

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Aminoglycoside resistance in multiply antibiotic-resistant Acinetobacter baumannii belonging to global clone 2 from Australian hospitals

Cited by 93 publications

References 29 publications

Characterization of Two Multidrug-Resistant IncA/C Plasmids from the 1960s by Using the MinION Sequencer Device

Characterization of Two Multidrug-Resistant IncA/C Plasmids from the 1960s by Using the MinION Sequencer Device

Antimicrobial Resistance Determinants in Acinetobacter baumannii Isolates Taken from Military Treatment Facilities

Distribution of Aminoglycoside Resistance Genes Among Acinetobacter Baumannii Strains Isolated From Burn Patients in Tehran, Iran

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