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Amorim JC, Carpio JM. Alpha-Naphthoflavone as a Novel Scaffold for the Design of Potential Inhibitors of the APH(3')-IIIa Nucleotide-Binding Site of Enterococcus faecalis. Microorganisms 2023; 11:2351. [PMID: 37764195 PMCID: PMC10535617 DOI: 10.3390/microorganisms11092351] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2023] [Revised: 07/28/2023] [Accepted: 07/28/2023] [Indexed: 09/29/2023] Open
Abstract
The spread of nosocomial infections caused by antibiotic-resistant Enterococcus faecalis is one of the major threats to global health at present. While aminoglycosides are often used to combat these infections, their effectiveness is reduced by various resistance mechanisms, including aminoglycoside modifying enzymes, and there are currently no drugs to inhibit these enzymes. To address this issue, this study was conducted to identify potential aminoglycoside adjuvants from a database of 462 flavones. The affinity of these molecules with the nucleotide-binding site (NBS) of aminoglycoside phosphotransferase type IIIa of E. faecalis (EfAPH(3')-IIIa) was evaluated, and the five molecules with the highest binding energies were identified. Of these, four were naphthoflavones, suggesting that their backbone could be useful in designing potential inhibitors. The highest-ranked naphthoflavone, 2-phenyl-4H-benzo[h]chromen-4-one, was modified to generate two new derivatives (ANF2OHC and ANF2OHCC) to interact with the NBS similarly to adenine in ATP. These derivatives showed higher binding free energies, better stability in molecular dynamics analysis and superior pharmacokinetic and toxicological profiles compared to the parent molecule. These findings suggest that these alpha-naphthoflavone derivatives are potential inhibitors of EfAPH(3')-IIIa and that this core may be a promising scaffold for developing adjuvants that restore the sensitivity of aminoglycosides.
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Affiliation(s)
| | - Juan Marcelo Carpio
- Unidad Académica de Salud y Bienestar, Universidad Católica de Cuenca, Av. Las Américas, Cuenca 010105, Ecuador;
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Fernandez JE, Seth-Smith HMB, Nordmann P, Egli A, Endimiani A, Perreten V. Intra- and Interspecies Spread of a Novel Conjugative Multidrug Resistance IncC Plasmid Coharboring blaOXA-181 and armA in a Cystic Fibrosis Patient. Microbiol Spectr 2022; 10:e0312122. [PMID: 36154665 PMCID: PMC9603557 DOI: 10.1128/spectrum.03121-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Accepted: 09/09/2022] [Indexed: 01/04/2023] Open
Abstract
A novel multidrug resistance conjugative 177,859-bp IncC plasmid pJEF1-OXA-181 coharboring the carbapenemase-coding blaOXA181 and the aminoglycoside resistance 16S rRNA methyltransferase-coding armA genes was detected in two unrelated Escherichia coli gut isolates of ST196 and ST648, as well as two ST35 Klebsiella pneumoniae gut and sputum isolates of a cystic fibrosis patient. The armA gene was located within the antimicrobial resistance island ARI-A and the blaOXA181 gene, which was preceded by IS903 and ISEcp1Δ was inserted within the transfer genes region without affecting conjugation ability. Comparative plasmid analysis with other related IncC plasmids showed the presence of blaOXA181, as well as its integration site, are thus far unique for these types of plasmids. This study illustrates the potential of a promiscuous multidrug resistance plasmid to acquire antibiotic resistance genes and to disseminate in the gut of the same host. IMPORTANCE Colocalization of carbapenemases and aminoglycoside resistance 16S rRNA methylases on a multidrug resistance conjugative plasmid poses a serious threat to public health. Here, we describe the novel IncC plasmid pJEF1-OXA-181 cocarrying blaOXA-181 and armA as well as several other antimicrobial resistance genes (ARGs) in different Enterobacterales isolates of the sputum and gut microbiota of a cystic fibrosis patient. IncC plasmids are conjugative, promiscuous elements which can incorporate accessory antimicrobial resistance islands making them key players in ARGs spread. This plasmid was thus far unique among IncC plasmids to contain a blaOXA-181 which was integrated in the transfer gene region without affecting its conjugation ability. This study highlights that new plasmids may be introduced into a hospital through different species hosted in one single patient. It further emphasizes the need of continuous surveillance of multidrug-resistant bacteria in patients at risk to avoid spread of such plasmids in the health care system.
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Affiliation(s)
- Javier E. Fernandez
- Division of Molecular bacterial Epidemiology and Infectious Diseases, Institute of Veterinary Bacteriology, Vetsuisse Faculty, University of Bern, Bern, Switzerland
- Graduate School of Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - Helena M. B. Seth-Smith
- Clinical Bacteriology and Mycology, University Hospital Basel, Basel, Switzerland
- Applied Microbiology Research, Department of Biomedicine, University of Basel, Basel, Switzerland
| | - Patrice Nordmann
- Swiss National Reference Center for Emerging Antibiotic Resistance (NARA), University of Fribourg, Fribourg, Switzerland
| | - Adrian Egli
- Clinical Bacteriology and Mycology, University Hospital Basel, Basel, Switzerland
- Applied Microbiology Research, Department of Biomedicine, University of Basel, Basel, Switzerland
| | - Andrea Endimiani
- Institute for Infectious Diseases (IFIK), University of Bern, Bern, Switzerland
| | - Vincent Perreten
- Division of Molecular bacterial Epidemiology and Infectious Diseases, Institute of Veterinary Bacteriology, Vetsuisse Faculty, University of Bern, Bern, Switzerland
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Rocha K, Magallon J, Reeves C, Phan K, Vu P, Oakley-Havens CL, Kwan S, Ramirez MS, LaVoi T, Donow H, Chapagain P, Santos R, Pinilla C, Giulianotti MA, Tolmasky ME. Inhibition of Aminoglycoside 6'- N-acetyltransferase Type Ib (AAC(6')-Ib): Structure-Activity Relationship of Substituted Pyrrolidine Pentamine Derivatives as Inhibitors. Biomedicines 2021; 9:biomedicines9091218. [PMID: 34572404 PMCID: PMC8471502 DOI: 10.3390/biomedicines9091218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Revised: 09/09/2021] [Accepted: 09/10/2021] [Indexed: 11/16/2022] Open
Abstract
The aminoglycoside 6'-N-acetyltransferase type Ib (AAC(6')-Ib) is a common cause of resistance to amikacin and other aminoglycosides in Gram-negatives. Utilization of mixture-based combinatorial libraries and application of the positional scanning strategy identified an inhibitor of AAC(6')-Ib. This inhibitor's chemical structure consists of a pyrrolidine pentamine scaffold substituted at four locations (R1, R3, R4, and R5). The substituents are two S-phenyl groups (R1 and R4), an S-hydroxymethyl group (R3), and a 3-phenylbutyl group (R5). Another location, R2, does not have a substitution, but it is named because its stereochemistry was modified in some compounds utilized in this study. Structure-activity relationship (SAR) analysis using derivatives with different functionalities, modified stereochemistry, and truncations was carried out by assessing the effect of the addition of each compound at 8 µM to 16 µg/mL amikacin-containing media and performing checkerboard assays varying the concentrations of the inhibitor analogs and the antibiotic. The results show that: (1) the aromatic functionalities at R1 and R4 are essential, but the stereochemistry is essential only at R4; (2) the stereochemical conformation at R2 is critical; (3) the hydroxyl moiety at R3 as well as stereoconformation are required for full inhibitory activity; (4) the phenyl functionality at R5 is not essential and can be replaced by aliphatic groups; (5) the location of the phenyl group on the butyl carbon chain at R5 is not essential; (6) the length of the aliphatic chain at R5 is not critical; and (7) all truncations of the scaffold resulted in inactive compounds. Molecular docking revealed that all compounds preferentially bind to the kanamycin C binding cavity, and binding affinity correlates with the experimental data for most of the compounds evaluated. The SAR results in this study will serve as the basis for the design of new analogs in an effort to improve their ability to induce phenotypic conversion to susceptibility in amikacin-resistant pathogens.
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Affiliation(s)
- Kenneth Rocha
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, Fullerton, CA 92831, USA; (K.R.); (J.M.); (C.R.); (K.P.); (P.V.); (C.L.O.-H.); (S.K.); (M.S.R.)
| | - Jesus Magallon
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, Fullerton, CA 92831, USA; (K.R.); (J.M.); (C.R.); (K.P.); (P.V.); (C.L.O.-H.); (S.K.); (M.S.R.)
| | - Craig Reeves
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, Fullerton, CA 92831, USA; (K.R.); (J.M.); (C.R.); (K.P.); (P.V.); (C.L.O.-H.); (S.K.); (M.S.R.)
| | - Kimberly Phan
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, Fullerton, CA 92831, USA; (K.R.); (J.M.); (C.R.); (K.P.); (P.V.); (C.L.O.-H.); (S.K.); (M.S.R.)
| | - Peter Vu
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, Fullerton, CA 92831, USA; (K.R.); (J.M.); (C.R.); (K.P.); (P.V.); (C.L.O.-H.); (S.K.); (M.S.R.)
| | - Crista L. Oakley-Havens
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, Fullerton, CA 92831, USA; (K.R.); (J.M.); (C.R.); (K.P.); (P.V.); (C.L.O.-H.); (S.K.); (M.S.R.)
| | - Stella Kwan
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, Fullerton, CA 92831, USA; (K.R.); (J.M.); (C.R.); (K.P.); (P.V.); (C.L.O.-H.); (S.K.); (M.S.R.)
| | - Maria Soledad Ramirez
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, Fullerton, CA 92831, USA; (K.R.); (J.M.); (C.R.); (K.P.); (P.V.); (C.L.O.-H.); (S.K.); (M.S.R.)
| | - Travis LaVoi
- Center for Translational Science, Florida International University, Port St. Lucie, FL 34987, USA; (T.L.); (H.D.); (C.P.); (M.A.G.)
| | - Haley Donow
- Center for Translational Science, Florida International University, Port St. Lucie, FL 34987, USA; (T.L.); (H.D.); (C.P.); (M.A.G.)
| | - Prem Chapagain
- Department of Physics, Florida International University, Miami, FL 33199, USA;
- Biomolecular Sciences Institute, Florida International University, Miami, FL 33199, USA
| | - Radleigh Santos
- Department of Mathematics, Nova Southeastern University, Fort Lauderdale, FL 33314, USA;
| | - Clemencia Pinilla
- Center for Translational Science, Florida International University, Port St. Lucie, FL 34987, USA; (T.L.); (H.D.); (C.P.); (M.A.G.)
| | - Marc A. Giulianotti
- Center for Translational Science, Florida International University, Port St. Lucie, FL 34987, USA; (T.L.); (H.D.); (C.P.); (M.A.G.)
| | - Marcelo E. Tolmasky
- Center for Applied Biotechnology Studies, Department of Biological Science, College of Natural Sciences and Mathematics, California State University Fullerton, Fullerton, CA 92831, USA; (K.R.); (J.M.); (C.R.); (K.P.); (P.V.); (C.L.O.-H.); (S.K.); (M.S.R.)
- Correspondence: ; Tel.: +1-657-278-5263
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Huang Y, Sokolowski K, Rana A, Singh N, Wang J, Chen K, Lang Y, Zhou J, Kadiyala N, Krapp F, Ozer EA, Hauser AR, Li J, Bulitta JB, Bulman ZP. Generating Genotype-Specific Aminoglycoside Combinations with Ceftazidime/Avibactam for KPC-Producing Klebsiella pneumoniae. Antimicrob Agents Chemother 2021; 65:e0069221. [PMID: 34152820 DOI: 10.1128/AAC.00692-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Antibiotic combinations, including ceftazidime/avibactam (CAZ/AVI), are frequently employed to combat KPC-producing Klebsiella pneumoniae (KPC-Kp), though such combinations have not been rationally optimized. Clinical KPC-Kp isolates with common genes encoding aminoglycoside-modifying enzymes (AMEs), aac(6')-Ib' or aac(6')-Ib, were used in static time-kill assays (n = 4 isolates) and the hollow-fiber infection model (HFIM; n = 2 isolates) to evaluate the activity of gentamicin, amikacin, and CAZ/AVI alone and in combinations. A short course, one-time aminoglycoside dose was also evaluated. Gentamicin plus CAZ/AVI was then tested in a mouse pneumonia model. Synergy with CAZ/AVI was more common with amikacin for aac(6')-Ib'-containing KPC-Kp but more common with gentamicin for aac(6')-Ib-containing isolates in time-kill assays. In the HFIM, although the isolates were aminoglycoside-susceptible at baseline, aminoglycoside monotherapies displayed variable initial killing, followed by regrowth and resistance emergence. CAZ/AVI combined with amikacin or gentamicin resulted in undetectable counts 50 h sooner than CAZ/AVI monotherapy against KPC-Kp with aac(6')-Ib'. CAZ/AVI monotherapy failed to eradicate KPC-Kp with aac(6')-Ib and a combination with gentamicin led to undetectable counts 70 h sooner than with amikacin. A one-time aminoglycoside dose with CAZ/AVI provided similar killing to aminoglycosides dosed for 7 days. In the mouse pneumonia model (n = 1 isolate), gentamicin and CAZ/AVI achieved a 6.0-log10 CFU/lung reduction at 24 h, which was significantly greater than either monotherapy (P < 0.005). Aminoglycosides in combination with CAZ/AVI were promising for KPC-Kp infections; this was true even for a one-time aminoglycoside dose. Selecting aminoglycosides based on AME genes or susceptibilities can improve the pharmacodynamic activity of the combination.
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Foudraine DE, Strepis N, Klaassen CHW, Raaphorst MN, Verbon A, Luider TM, Goessens WHF, Dekker LJM. Rapid and Accurate Detection of Aminoglycoside-Modifying Enzymes and 16S rRNA Methyltransferases by Targeted Liquid Chromatography-Tandem Mass Spectrometry. J Clin Microbiol 2021; 59:e0046421. [PMID: 33910961 DOI: 10.1128/JCM.00464-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
New and rapid diagnostic methods are needed for the detection of antimicrobial resistance to aid in curbing drug-resistant infections. Targeted liquid chromatography-tandem mass spectrometry (LC-MS/MS) is a method that could serve this purpose, as it can detect specific peptides of antimicrobial resistance mechanisms with high accuracy. In the current study, we developed an accurate and rapid targeted LC-MS/MS assay based on parallel reaction monitoring for detection of the most prevalent aminoglycoside-modifying enzymes and 16S rRNA methyltransferases in Escherichia coli and Klebsiella pneumoniae that confer resistance to aminoglycosides. Specific tryptic peptides needed for detection were selected and validated for AAC(3)-Ia, AAC(3)-II, AAC(3)-IV, AAC(3)-VI, AAC(6')-Ib, AAC(6')-Ib-cr, ANT(2″)-I, APH(3')-VI, ArmA, RmtB, RmtC, and RmtF. In total, 205 isolates containing different aminoglycoside resistance mechanisms that consisted mostly of E. coli and K. pneumoniae were selected for assay development and evaluation. Mass spectrometry results were automatically analyzed and were compared to whole-genome sequencing results. Of the 2,460 isolate and resistance mechanism combinations tested, 2,416 combinations matched. Discrepancies were further analyzed by repeating LC-MS/MS analysis and performing additional PCRs. Mass spectrometry results were also used to predict resistance and susceptibility to gentamicin, tobramycin, and amikacin in only the E. coli and K. pneumoniae isolates (n = 191). The category interpretations were correctly predicted for gentamicin in 97.4% of the isolates, for tobramycin in 97.4% of the isolates, and for amikacin in 82.7% of the isolates. Targeted LC-MS/MS can be applied for accurate and rapid detection of aminoglycoside resistance mechanisms.
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Rashvand P, Peymani A, Mohammadi M, Karami A, Samimi R, Hajian S, Porasgari D, Habibollah-Pourzereshki N. Molecular survey of aminoglycoside-resistant Acinetobacter baumannii isolated from tertiary hospitals in Qazvin, Iran. New Microbes New Infect 2021; 42:100883. [PMID: 34094583 PMCID: PMC8165567 DOI: 10.1016/j.nmni.2021.100883] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 04/10/2021] [Accepted: 04/19/2021] [Indexed: 11/30/2022] Open
Abstract
Aminoglycoside-modifying enzymes (AMEs) and 16S rRNA methylases (16S RMTase) are two main resistance mechanisms against aminoglycosides. This study aimed to evaluate the frequency of AMEs and 16S rRNA methylase genes among aminoglycoside non-susceptible Acinetobacter baumannii isolates and to assess their clonal relationship using repetitive extragenic palindromic-PCR (rep-PCR). In this cross-sectional study, a total of 192 A. baumannii isolates were collected from the patients hospitalized in Qazvin, Iran (January 2016 to January 2018). Identification of isolates was performed by standard laboratory methods and API 20E strips. Antimicrobial susceptibility was determined by Kirby–Bauer method followed by examination of the genes encoding the AMEs and 16S RMTase by PCR and sequencing methods. The clonal relationship of isolates was carried out by rep-PCR. In total, 98.4% of isolates were non-susceptible to aminoglycosides, 98.4%, 97.9% and 83.9% of isolates were found to be non-susceptible against gentamicin, tobramycin and amikacin, respectively. The frequencies of aph(3′)-VI, aac(6′)-Ib, aac(3)-II, aph(3′)-Ia and armA genes were 59.3%, 39.2%, 39.2%, 31.7% and 69.8%, respectively, either alone or in combination. Rep-PCR results showed that the aminoglycoside non-susceptible isolates belonged to three distinct clones: A (79.4%), B (17.5%) and C (3.2%). The findings of this study showed a high frequency for AMEs with the emergence of armA genes among the aminoglycoside non-susceptible A. baumannii isolates. Rational administration of aminoglycosides as well as using an appropriate infection control policy may reduce the presence of resistance to antibiotics in medical centres. Little is known regarding carbapenem resistance mechanisms in A. baumannii in our region. More than 85% of our isolates were non-susceptible to carbapenems in Qazvin hospitals, Iran. blaOXA-23, blaOXA-24, blaIMP-1, and blaVIM-1 genes is established in carbapenem resistant A. baumannii isolates. Clonal distribution of carbapenem resistant A. baumannii was demonstrated in investigated hospital settings.
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Affiliation(s)
- P. Rashvand
- Student Research Committee, Qazvin University of Medical Sciences, Qazvin, Iran
| | - A. Peymani
- Medical Microbiology Research Centre, Qazvin University of Medical Sciences, Qazvin, Iran
- Corresponding author: A. Peymani, Medical Microbiology Research Centre, Qazvin University of Medical Sciences, Minoodar, Velayat Hospital, Qazvin, Iran.
| | - M. Mohammadi
- Student Research Committee, Qazvin University of Medical Sciences, Qazvin, Iran
| | - A.A. Karami
- Department of Urology, School of Medicine, Qazvin University of Medical Sciences, Qazvin, Iran
| | - R. Samimi
- Medical Microbiology Research Centre, Qazvin University of Medical Sciences, Qazvin, Iran
| | - S. Hajian
- Department of Nephrology, Velayat Hospital, Qazvin University of Medical Sciences, Qazvin, Iran
| | - D. Porasgari
- Medical Microbiology Research Centre, Qazvin University of Medical Sciences, Qazvin, Iran
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Bordeleau E, Stogios PJ, Evdokimova E, Koteva K, Savchenko A, Wright GD. ApmA Is a Unique Aminoglycoside Antibiotic Acetyltransferase That Inactivates Apramycin. mBio 2021; 12:e02705-20. [PMID: 33563840 DOI: 10.1128/mBio.02705-20] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Apramycin is an aminoglycoside antibiotic with the potential to be developed to combat multidrug-resistant pathogens. Its unique structure evades the clinically widespread mechanisms of aminoglycoside resistance that currently compromise the efficacy of other members in this drug class. Of the aminoglycoside-modifying enzymes that chemically alter these antibiotics, only AAC(3)-IVa has been demonstrated to confer resistance to apramycin through N-acetylation. Knowledge of other modification mechanisms is important to successfully develop apramycin for clinical use. Here, we show that ApmA is structurally unique among the previously described aminoglycoside-modifying enzymes and capable of conferring a high level of resistance to apramycin. In vitro experiments indicated ApmA to be an N-acetyltransferase, but in contrast to AAC(3)-IVa, ApmA has a unique regiospecificity of the acetyl transfer to the N2' position of apramycin. Crystallographic analysis of ApmA conclusively showed that this enzyme is an acetyltransferase from the left-handed β-helix protein superfamily (LβH) with a conserved active site architecture. The success of apramycin will be dependent on consideration of the impact of this potential form of clinical resistance.IMPORTANCE Apramycin is an aminoglycoside antibiotic that has been traditionally used in veterinary medicine. Recently, it has become an attractive candidate to repurpose in the fight against multidrug-resistant pathogens prioritized by the World Health Organization. Its atypical structure circumvents most of the clinically relevant mechanisms of resistance that impact this class of antibiotics. Prior to repurposing apramycin, it is important to understand the resistance mechanisms that could be a liability. Our study characterizes the most recently identified apramycin resistance element, apmA We show ApmA does not belong to the protein families typically associated with aminoglycoside resistance and is responsible for modifying a different site on the molecule. The data presented will be critical in the development of apramycin derivatives that will evade apmA in the event it becomes prevalent in the clinic.
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Seupt A, Schniederjans M, Tomasch J, Häussler S. Expression of the MexXY Aminoglycoside Efflux Pump and Presence of an Aminoglycoside-Modifying Enzyme in Clinical Pseudomonas aeruginosa Isolates Are Highly Correlated. Antimicrob Agents Chemother 2020; 65:e01166-20. [PMID: 33046496 DOI: 10.1128/AAC.01166-20] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Accepted: 09/15/2020] [Indexed: 12/26/2022] Open
Abstract
The impact of MexXY efflux pump expression on aminoglycoside resistance in clinical Pseudomonas aeruginosa isolates has been debated. In this study, we found that, in general, elevated mexXY gene expression levels in clinical P. aeruginosa isolates confer to slight increases in aminoglycoside MIC levels; however, those levels rarely lead to clinically relevant resistance phenotypes. The main driver of resistance in the clinical isolates studied here was the acquisition of aminoglycoside-modifying enzymes (AMEs). The impact of MexXY efflux pump expression on aminoglycoside resistance in clinical Pseudomonas aeruginosa isolates has been debated. In this study, we found that, in general, elevated mexXY gene expression levels in clinical P. aeruginosa isolates confer to slight increases in aminoglycoside MIC levels; however, those levels rarely lead to clinically relevant resistance phenotypes. The main driver of resistance in the clinical isolates studied here was the acquisition of aminoglycoside-modifying enzymes (AMEs). Nevertheless, acquisition of an AME was strongly associated with mexY overexpression. In line with this observation, we demonstrate that the introduction of a gentamicin acetyltransferase confers to full gentamicin resistance levels in a P. aeruginosa type strain only if the MexXY efflux pump was active. We discuss that increased mexXY activity in clinical AME-harboring P. aeruginosa isolates might affect ion fluxes at the bacterial cell membrane and thus might play a role in the establishment of enhanced fitness that extends beyond aminoglycoside resistance.
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Khodabandeh M, Mohammadi M, Abdolsalehi MR, Hasannejad-Bibalan M, Gholami M, Alvandimanesh A, Pournajaf A, Rajabnia R. High-Level Aminoglycoside Resistance in Enterococcus Faecalis and Enterococcus Faecium; as a Serious Threat in Hospitals. Infect Disord Drug Targets 2020; 20:223-228. [PMID: 30499420 DOI: 10.2174/1871526519666181130095954] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2018] [Revised: 09/08/2018] [Accepted: 11/20/2018] [Indexed: 12/12/2022]
Abstract
AIMS AND OBJECTIVES The present work aimed to evaluate the frequency of aminoglycoside- modifying enzymes encoding genes in the E. faecalis and E. faecium and their antibiotic resistance profile. METHODS A total of 305 different clinical samples were subjected for identification and antibiotic susceptibility test. The high-level aminoglycoside resistance was identified by MIC and Kirby Bauer disc diffusion method. The prevalence of aac (6')-Ie-aph (2'')-Ia, aph (3')-IIIa and ant (4')- Ia genes was determined by multiplex- PCR. In total, 100 enterococci strains were isolated. The prevalence of E. faecalis and E. faecium isolates was 78% and 22%, respectively. RESULTS All isolates were susceptible to linezolid. So, all E. faecalis were susceptible to vancomycin but, 36.4% of E. faecium were resistant to it. The prevalence of multiple drug resistance strains was 100% and 67.9% of E. faecium and E. faecalis, respectively. High-level-gentamicin and streptomycin resistant rates were as follows; 26.9% and 73.1% of E. faecalis and 77.3% and 90.1% of E. faecium. Conclucion: The results of the current study showed a high frequency of aac (6')-Ie-aph (2'')-Ia genes among enterococcal isolates. A high rate of resistance to antimicrobials in Enterococcus is obviously problematic, and a novel policy is needed to decrease resistance in these microorganisms.
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Affiliation(s)
- Mahmoud Khodabandeh
- Department of Infectious Diseases, Pediatric's Center of Excellence, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Mohsen Mohammadi
- Non-Communicable Pediatric Diseases Research Center, Health Research Institute, Babol University of Medical Sciences, Babol, Iran
| | - Mohammad Reza Abdolsalehi
- Department of Infectious Diseases, Pediatric's Center of Excellence, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran
| | | | - Mehrdad Gholami
- Department of Microbiology and Virology, Faculty of Medicine, Mazandaran University of Medical Sciences, Sari, Iran
| | - Azadeh Alvandimanesh
- Department of pathology, Shafa hospital, Qazvin University of Medical Sciences, Qazvin, Iran
| | - Abazar Pournajaf
- Department of Microbiology, Faculty of Medicine, Babol University of Medical Sciences, Babol, Iran
| | - Ramazan Rajabnia
- Infectious Diseases and Tropical Medicine Research Center, Babol University of Medical Sciences, Babol, Iran
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Bulman ZP, Cirz R, Hildebrandt D, Kane T, Rosario Z, Wlasichuk K, Park M, Andrews LD. Unraveling the Gentamicin Drug Product Complexity Reveals Variation in Microbiological Activities and Nephrotoxicity. Antimicrob Agents Chemother 2020; 64:e00533-20. [PMID: 32601158 DOI: 10.1128/AAC.00533-20] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Accepted: 06/18/2020] [Indexed: 11/20/2022] Open
Abstract
The gentamicin drug product is a complex mixture of numerous components, many of which have not individually undergone safety and efficacy assessments. This is in contrast to the majority of medicines that require rigorous characterizations of trace impurities and are dosed as single components. In gentamicin, four components, known as gentamicin congeners C1, C1a, C2, and C2a, comprise the majority of the mixture. A liquid chromatography-mass spectroscopy analysis revealed that the relative abundances of each gentamicin congener in commercial formulations can vary up to 1.9-fold depending on the commercial source of the gentamicin. To determine if the gentamicin used for antibiotic susceptibility testing (AST) would be predictive of the microbiological activity of the product used to dose patients, the relative abundances of the four congeners contained on commercial AST disks were measured. It was found that the congener abundances on the commercial AST disks varied up to 4.1-fold. After purification of the four gentamicin congeners, similar potencies against bacterial strains lacking aminoglycoside-modifying enzymes (AMEs) were observed. However, the potency of the congeners against strains harboring a common AME differed up to 128-fold. Nephrotoxicity of the individual gentamicin congeners also differed significantly in cell-based and repeat-dose rat nephrotoxicity studies. Variations in the composition of commercial gentamicin products combined with toxicity differences between gentamicin congeners suggest that some gentamicin formulations may be more nephrotoxic. Our results also raise the concern that gentamicin susceptibility test results may not be predictive of patient outcomes and could lead to unexpected clinical treatment failures.
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Pragasam AK, Jennifer SL, Solaimalai D, Muthuirulandi Sethuvel DP, Rachel T, Elangovan D, Vasudevan K, Gunasekaran K, Veeraraghavan B. Expected plazomicin susceptibility in India based on the prevailing aminoglycoside resistance mechanisms in Gram-negative organisms derived from whole-genome sequencing. Indian J Med Microbiol 2020; 38:313-318. [PMID: 33154241 DOI: 10.4103/ijmm.ijmm_20_384] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Background Aminoglycoside resistance is a growing challenge, and it is commonly mediated by the aminoglycoside-modifying enzymes (AMEs), followed by 16S rRNA methyl transferase. Plazomicin, a novel aminoglycoside agent approved by the Food and Drug Administration for complicated urinary tract infections is proven to overcome resistance mediated by AMEs but not due to 16S rRNA methyl transferase (16SRMTases). We undertook this study to predict the efficacy of plazomicin in India based on the antimicrobial resistance profile derived from whole-genome sequencing (WGS). Methodology A total of 386 clinical isolates of Escherichia coli, Klebsiella pneumoniae and Acinetobacter baumannii subjected to WGS were screened for aminoglycoside-resistance mechanisms such as AMEs and 16SRMTases and its association with carbapenemases. Results AMEs was present in all E. coli, A. baumannii and in 90% of K. pneumoniae. In addition, up to 47% of E. coli and 38% of K. pneumoniae co-carried 16SRMTases with AMEs genes. However, A. baumannii showed 87% of isolates co-harbouring 16SRMTase. bla NDM, bla Oxa-48-like and bla Oxa-23-like were the most predominant carbapenemases in E. coli, K. pneumoniae and A. baumannii, respectively. Notably, 48% of NDM-producing E. coli and 35% of Oxa-48-like producing K. pneumoniae were identified to co-harbour AMEs + RMTAses, where plazomicin may not be useful. Conclusion Overall, 53%, 62% and 14% of carbapenemase-producing E. coli, K. pneumoniae and A. baumannii harbours only AMEs, indicating the role of plazomicin use. Plazomicin can be used both for ESBLs as "carbapenem-sparing agent" and carbapenemase producers as "colistin-sparing agent." For optimal use, it is essential to know the molecular epidemiology of resistance in a given geographical region where plazomicin empirical therapy is considered.
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Affiliation(s)
- Agila Kumari Pragasam
- Department of Clinical Microbiology, Christian Medical College, Vellore, Tamil Nadu, India
| | - S Lydia Jennifer
- Department of Clinical Microbiology, Christian Medical College, Vellore, Tamil Nadu, India
| | | | | | - Tanya Rachel
- Department of Clinical Microbiology, Christian Medical College, Vellore, Tamil Nadu, India
| | - Divyaa Elangovan
- Department of Clinical Microbiology, Christian Medical College, Vellore, Tamil Nadu, India
| | - Karthick Vasudevan
- Department of Clinical Microbiology, Christian Medical College, Vellore, Tamil Nadu, India
| | - Karthick Gunasekaran
- Department of General Medicine (Unit.V), Christian Medical College, Vellore, Tamil Nadu, India
| | - Balaji Veeraraghavan
- Department of Clinical Microbiology, Christian Medical College, Vellore, Tamil Nadu, India
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Beigverdi R, Sattari-Maraji A, Jabalameli F, Emaneini M. Prevalence of Genes Encoding Aminoglycoside-Modifying Enzymes in Clinical Isolates of Gram-Positive Cocci in Iran: A Systematic Review and Meta-Analysis. Microb Drug Resist 2020; 26:126-135. [PMID: 31464570 DOI: 10.1089/mdr.2019.0139] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Introduction: Several studies have investigated the genes encoding aminoglycoside-modifying enzymes (AMEs) among gram-positive cocci (GPC) such as Staphylococcus aureus, methicillin-resistant S. aureus (MRSA), coagulase-negative staphylococci (CoNS), and Enterococcus spp. in Iran; however, a comprehensive analysis has not yet been performed. Thus, the present systematic review and meta-analysis was conducted to determine the prevalence of genes encoding AMEs among GPC in Iran. Methods: A systematic review of the data published in the English and Persian languages from January 2000 to October 2018 was performed by searching different electronic databases (Medline, Embase, Web of Science, and the Iranian Database). Meta-analysis was performed by using the Comprehensive Meta-Analysis (Biostat V2.2) software. Cochran's Q and I2 statistics were used to test heterogeneity, and publication bias was assessed by using funnel plot and Begg's and Egger's tests. Results: Out of 117 studies, 28 were considered eligible for inclusion in the current meta-analysis. The most prevalent AMEs gene among GPC was aac(6')-Ie-aph(2'')-Ia, with a prevalence of 97.7% (95% CI; 94.4-99) in high-level gentamicin-resistant enterococci and 67.7% (95% CI; 59.2-75.2) in MRSA. The second most common gene was ant(4')Ia, with a prevalence of 45.3% (95% CI; 23.9-68.6) in MRSA. Conclusions: It was ultimately determined that the prevalence of AMEs genes among GPC had reached alarming levels in Iran; therefore, aminoglycosides should be prescribed with caution by clinicians. The implementation of a regional and nationwide surveillance system to monitor antimicrobial resistance, especially aminoglycosides, and increasing the awareness of AMEs genes among clinicians are essential to guiding empirical and pathogen-specific therapy.
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Affiliation(s)
- Reza Beigverdi
- Department of Microbiology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Azin Sattari-Maraji
- Department of Microbiology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Fereshteh Jabalameli
- Department of Microbiology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Mohammad Emaneini
- Department of Microbiology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
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Tada T, Hishinuma T, Watanabe S, Uchida H, Tohya M, Kuwahara-Arai K, Mya S, Zan KN, Kirikae T, Tin HH. Molecular Characterization of Multidrug-Resistant Pseudomonas aeruginosa Isolates in Hospitals in Myanmar. Antimicrob Agents Chemother 2019; 63:e02397-18. [PMID: 30803967 DOI: 10.1128/AAC.02397-18] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Accepted: 02/19/2019] [Indexed: 11/20/2022] Open
Abstract
The emergence of multidrug-resistant (MDR) Pseudomonas aeruginosa has become a serious worldwide medical problem. This study was designed to clarify the genetic and epidemiological properties of MDR P. aeruginosa strains isolated from hospitals in Myanmar. Forty-five MDR P. aeruginosa isolates obtained from different patients in seven hospitals in Myanmar were screened using the broth microdilution method. The whole genomes of the MDR isolates were sequenced using a MiSeq platform (Illumina). Phylogenetic trees were constructed from single nucleotide polymorphism concatemers. Multilocus sequence types were deduced, and drug resistance genes were identified. Of the 45 isolates, 38 harbored genes encoding carbapenemases, including DIM-1, IMP-1, NDM-1, VIM-2, and VIM-5, and 9 isolates had genes encoding 16S rRNA methylases, including RmtB, RmtD3, RmtE, and RmtF2. Most MDR P. aeruginosa strains isolated in Myanmar belonged to sequence type 1047 (ST1047). This is the first molecular epidemiological analysis of MDR P. aeruginosa clinical isolates in Myanmar. These findings strongly suggest that P. aeruginosa ST1047 strains harboring carbapenemases, including DIM-, IMP-, NDM-, and VIM-type metallo-β-lactamases, have been spreading throughout medical settings in Myanmar.
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Fabre A, Oleastro M, Nunes A, Santos A, Sifré E, Ducournau A, Bénéjat L, Buissonnière A, Floch P, Mégraud F, Dubois V, Lehours P. Whole-Genome Sequence Analysis of Multidrug-Resistant Campylobacter Isolates: a Focus on Aminoglycoside Resistance Determinants. J Clin Microbiol 2018; 56:e00390-18. [PMID: 29976591 PMCID: PMC6113490 DOI: 10.1128/jcm.00390-18] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Accepted: 06/28/2018] [Indexed: 01/03/2023] Open
Abstract
A whole-genome sequencing (WGS) approach was conducted in order to identify the molecular determinants associated with antimicrobial resistance in 12 multidrug-resistant Campylobacter jejuni and Campylobacter coli isolates, with a focus on aminoglycoside resistance determinants. Two variants of a new aminoglycoside phosphotransferase gene [aph(2″)-Ii1 and aph(2″)-Ii2 ] putatively associated with gentamicin resistance were found. In addition, the following new genes were identified for the first time in Campylobacter: a lincosamide nucleotidyltransferase gene [lnu(G)], likely associated with lincomycin resistance, and two resistance enzyme genes (spw and apmA) similar to those found in Staphylococcus aureus, which may confer spectinomycin and gentamicin resistance, respectively. A C1192T mutation of the 16S rRNA gene that may be involved in spectinomycin resistance was also found in a C. coli isolate. Genes identified in the present study were located either on the bacterial chromosome or on plasmids that could be transferred naturally. Their role in aminoglycoside resistance remains to be supported by genetic studies. Regarding the other antimicrobial agents studied, i.e., ampicillin, ciprofloxacin, erythromycin, and tetracycline, a perfect correlation between antimicrobial phenotypes and genotypes was found. Overall, our data suggest that WGS analysis is a powerful tool for identifying resistance determinants in Campylobacter and can disclose the full genetic elements associated with resistance, including antimicrobial compounds not tested routinely in antimicrobial susceptibility testing.
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Affiliation(s)
- Adrien Fabre
- CHU de Bordeaux, National Reference Center for Campylobacter and Helicobacter, Bordeaux, France
- INSERM, University of Bordeaux, UMR1053 Bordeaux Research in Translational Oncology, BaRITOn, Bordeaux, France
| | - Monica Oleastro
- National Reference Laboratory of Gastrointestinal Infections, Department of Infectious Diseases, National Institute of Health, Lisbon, Portugal
| | - Alexandra Nunes
- Bioinformatics Unit, Department of Infectious Diseases, National Institute of Health, Lisbon, Portugal
| | - Andrea Santos
- National Reference Laboratory of Gastrointestinal Infections, Department of Infectious Diseases, National Institute of Health, Lisbon, Portugal
| | - Elodie Sifré
- CHU de Bordeaux, National Reference Center for Campylobacter and Helicobacter, Bordeaux, France
- INSERM, University of Bordeaux, UMR1053 Bordeaux Research in Translational Oncology, BaRITOn, Bordeaux, France
| | - Astrid Ducournau
- CHU de Bordeaux, National Reference Center for Campylobacter and Helicobacter, Bordeaux, France
- INSERM, University of Bordeaux, UMR1053 Bordeaux Research in Translational Oncology, BaRITOn, Bordeaux, France
| | - Lucie Bénéjat
- CHU de Bordeaux, National Reference Center for Campylobacter and Helicobacter, Bordeaux, France
- INSERM, University of Bordeaux, UMR1053 Bordeaux Research in Translational Oncology, BaRITOn, Bordeaux, France
| | - Alice Buissonnière
- CHU de Bordeaux, National Reference Center for Campylobacter and Helicobacter, Bordeaux, France
- INSERM, University of Bordeaux, UMR1053 Bordeaux Research in Translational Oncology, BaRITOn, Bordeaux, France
| | - Pauline Floch
- CHU de Bordeaux, National Reference Center for Campylobacter and Helicobacter, Bordeaux, France
- INSERM, University of Bordeaux, UMR1053 Bordeaux Research in Translational Oncology, BaRITOn, Bordeaux, France
| | - Francis Mégraud
- CHU de Bordeaux, National Reference Center for Campylobacter and Helicobacter, Bordeaux, France
- INSERM, University of Bordeaux, UMR1053 Bordeaux Research in Translational Oncology, BaRITOn, Bordeaux, France
| | | | - Philippe Lehours
- CHU de Bordeaux, National Reference Center for Campylobacter and Helicobacter, Bordeaux, France
- INSERM, University of Bordeaux, UMR1053 Bordeaux Research in Translational Oncology, BaRITOn, Bordeaux, France
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Abstract
Acinetobacter baumannii has become an important pathogen in hospitals worldwide, where the incidence of these infections has been increasing. A. baumannii infections have become exceedingly difficult to treat due to a rapid increase in the frequency of multidrug- and pan-resistant isolates. This has prompted the World Health Organization to list A. baumannii as the top priority for the research and development of new antibiotics. This study reports for the first time a detailed analysis of aminoglycoside heteroresistance in A. baumannii. We define the mechanistic basis for heteroresistance, where the aadB(ant2″)Ia gene encoding an aminoglycoside adenylyltransferase becomes highly amplified in a RecA-dependent manner. Remarkably, this amplification of 20 to 40 copies occurs stochastically in 1/200 cells in the absence of antibiotic selection. In addition, we provide evidence for a second RecA-independent mechanism for aminoglycoside heteroresistance. This study reveals that aminoglycoside resistance in A. baumannii is far more complex than previously realized and has important implications for the use of aminoglycosides in treating A. baumannii infections. Heteroresistance is a phenomenon where a subpopulation of cells exhibits higher levels of antibiotic resistance than the general population. Analysis of tobramycin resistance in Acinetobacter baumannii AB5075 using Etest strips demonstrated that colonies with increased resistance arose at high frequency within the zone of growth inhibition. The presence of a resistant subpopulation was confirmed by population analysis profiling (PAP). The tobramycin-resistant subpopulation was cross resistant to gentamicin but not amikacin. The increased tobramycin resistance phenotype was highly unstable, and cells reverted to a less resistant population at frequencies of 60 to 90% after growth on nonselective media. Furthermore, the frequency of the resistant subpopulation was not increased by preincubation with subinhibitory concentrations of tobramycin. The tobramycin-resistant subpopulation was shown to replicate during the course of antibiotic treatment, demonstrating that these were not persister cells. In A. baumannii AB5075, a large plasmid (p1AB5075) carries aadB, a 2″-nucleotidyltransferase that confers resistance to both tobramycin and gentamicin but not amikacin. The aadB gene is part of an integron and is carried adjacent to four additional resistance genes that are all flanked by copies of an integrase gene. In isolates with increased resistance, this region was highly amplified in a RecA-dependent manner. However, in a recA mutant, colonies with unstable tobramycin resistance arose by a mechanism that did not involve amplification of this region. These data indicate that tobramycin heteroresistance occurs by at least two mechanisms in A. baumannii, and future studies to determine its effect on patient outcomes are warranted. IMPORTANCEAcinetobacter baumannii has become an important pathogen in hospitals worldwide, where the incidence of these infections has been increasing. A. baumannii infections have become exceedingly difficult to treat due to a rapid increase in the frequency of multidrug- and pan-resistant isolates. This has prompted the World Health Organization to list A. baumannii as the top priority for the research and development of new antibiotics. This study reports for the first time a detailed analysis of aminoglycoside heteroresistance in A. baumannii. We define the mechanistic basis for heteroresistance, where the aadB(ant2″)Ia gene encoding an aminoglycoside adenylyltransferase becomes highly amplified in a RecA-dependent manner. Remarkably, this amplification of 20 to 40 copies occurs stochastically in 1/200 cells in the absence of antibiotic selection. In addition, we provide evidence for a second RecA-independent mechanism for aminoglycoside heteroresistance. This study reveals that aminoglycoside resistance in A. baumannii is far more complex than previously realized and has important implications for the use of aminoglycosides in treating A. baumannii infections.
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16
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Sonousi A, Sarpe VA, Brilkova M, Schacht J, Vasella A, Böttger EC, Crich D. Effects of the 1- N-(4-Amino-2 S-hydroxybutyryl) and 6'- N-(2-Hydroxyethyl) Substituents on Ribosomal Selectivity, Cochleotoxicity, and Antibacterial Activity in the Sisomicin Class of Aminoglycoside Antibiotics. ACS Infect Dis 2018; 4:1114-1120. [PMID: 29708331 DOI: 10.1021/acsinfecdis.8b00052] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Syntheses of the 6'- N-(2-hydroxyethyl) and 1- N-(4-amino-2 S-hydroxybutyryl) derivatives of the 4,6-aminoglycoside sisomicin and that of the doubly modified 1- N-(4-amino-2 S-hydroxybutyryl)-6'- N-(2-hydroxyethyl) derivative known as plazomicin are reported together with their antibacterial and antiribosomal activities and selectivities. The 6'- N-(2-hydroxyethyl) modification results in a moderate increase in prokaryotic/eukaryotic ribosomal selectivity, whereas the 1- N-(4-amino-2 S-hydroxybutyryl) modification has the opposite effect. When combined in plazomicin, the effects of the two groups on ribosomal selectivity cancel each other out, leading to the prediction that plazomicin will exhibit ototoxicity comparable to those of the parent and the current clinical aminoglycoside antibiotics gentamicin and tobramycin, as borne out by ex vivo studies with mouse cochlear explants. The 6'- N-(2-hydroxyethyl) modification restores antibacterial activity in the presence of the AAC(6') aminoglycoside-modifying enzymes, while the 1- N-(4-amino-2 S-hydroxybutyryl) modification overcomes resistance to the AAC(2') class but is still affected to some extent by the AAC(3) class. Neither modification is able to circumvent the ArmA ribosomal methyltransferase-induced aminoglycoside resistance. The use of phenyltriazenyl protection for the secondary amino group of sisomicin facilitates the synthesis of each derivative and their characterization through the provision of sharp NMR spectra for all intermediates.
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Affiliation(s)
- Amr Sonousi
- Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, Michigan 48202, United States
| | - Vikram A. Sarpe
- Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, Michigan 48202, United States
| | - Margarita Brilkova
- Institut für Medizinische Mikrobiologie, Universität Zürich, Gloriastrasse 28/30, 8006 Zürich, Switzerland
| | - Jochen Schacht
- Kresge Hearing Research Institute, Department of Otolaryngology, University of Michigan, 1150 West Medical Center Drive, Ann Arbor, Michigan 48109, United States
| | - Andrea Vasella
- Laboratorium für Organische Chemie, ETH Zürich, Vladimir-Prelog-Weg 1-5/10, 8093 Zürich, Switzerland
| | - Erik C. Böttger
- Institut für Medizinische Mikrobiologie, Universität Zürich, Gloriastrasse 28/30, 8006 Zürich, Switzerland
| | - David Crich
- Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, Michigan 48202, United States
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Cox G, Ejim L, Stogios PJ, Koteva K, Bordeleau E, Evdokimova E, Sieron AO, Savchenko A, Serio AW, Krause KM, Wright GD. Plazomicin Retains Antibiotic Activity against Most Aminoglycoside Modifying Enzymes. ACS Infect Dis 2018; 4:980-987. [PMID: 29634241 DOI: 10.1021/acsinfecdis.8b00001] [Citation(s) in RCA: 75] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Plazomicin is a next-generation, semisynthetic aminoglycoside antibiotic currently under development for the treatment of infections due to multidrug-resistant Enterobacteriaceae. The compound was designed by chemical modification of the natural product sisomicin to provide protection from common aminoglycoside modifying enzymes that chemically alter these drugs via N-acetylation, O-adenylylation, or O-phosphorylation. In this study, plazomicin was profiled against a panel of isogenic strains of Escherichia coli individually expressing twenty-one aminoglycoside resistance enzymes. Plazomicin retained antibacterial activity against 15 of the 17 modifying enzyme-expressing strains tested. Expression of only two of the modifying enzymes, aac(2')-Ia and aph(2″)-IVa, decreased plazomicin potency. On the other hand, expression of 16S rRNA ribosomal methyltransferases results in a complete lack of plazomicin potency. In vitro enzymatic assessment confirmed that AAC(2')-Ia and APH(2'')-IVa (aminoglycoside acetyltransferase, AAC; aminoglycoside phosphotransferase, APH) were able to utilize plazomicin as a substrate. AAC(2')-Ia and APH(2'')-IVa are limited in their distribution to Providencia stuartii and Enterococci, respectively. These data demonstrate that plazomicin is not modified by a broad spectrum of common aminoglycoside modifying enzymes including those commonly found in Enterobacteriaceae. However, plazomicin is inactive in the presence of 16S rRNA ribosomal methyltransferases, which should be monitored in future surveillance programs.
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Affiliation(s)
- Georgina Cox
- M.G. DeGroote Institute for Infectious Disease Research, Department of Biochemistry and Biomedical Sciences, DeGroote School of Medicine, McMaster University, 1280 Main Street West, Hamilton, Ontario L8N 4K1, Canada
| | - Linda Ejim
- M.G. DeGroote Institute for Infectious Disease Research, Department of Biochemistry and Biomedical Sciences, DeGroote School of Medicine, McMaster University, 1280 Main Street West, Hamilton, Ontario L8N 4K1, Canada
| | - Peter J. Stogios
- Center for Structural Genomics of Infectious Diseases (CSGID) and Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario M5G 1L6, Canada
| | - Kalinka Koteva
- M.G. DeGroote Institute for Infectious Disease Research, Department of Biochemistry and Biomedical Sciences, DeGroote School of Medicine, McMaster University, 1280 Main Street West, Hamilton, Ontario L8N 4K1, Canada
| | - Emily Bordeleau
- M.G. DeGroote Institute for Infectious Disease Research, Department of Biochemistry and Biomedical Sciences, DeGroote School of Medicine, McMaster University, 1280 Main Street West, Hamilton, Ontario L8N 4K1, Canada
| | - Elena Evdokimova
- Center for Structural Genomics of Infectious Diseases (CSGID) and Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario M5G 1L6, Canada
| | - Arthur O. Sieron
- M.G. DeGroote Institute for Infectious Disease Research, Department of Biochemistry and Biomedical Sciences, DeGroote School of Medicine, McMaster University, 1280 Main Street West, Hamilton, Ontario L8N 4K1, Canada
| | - Alexei Savchenko
- Center for Structural Genomics of Infectious Diseases (CSGID) and Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario M5G 1L6, Canada
- Department of Microbiology, Immunology and Infectious Diseases, Health Research Innovation Centre, University of Calgary, 3330 Hospital Drive NW, HRIC-2C66, Calgary, Alberta T2N 4N1, Canada
| | - Alisa W. Serio
- Achaogen, One Tower Place, Suite 300, South San Francisco, California 94080, United States
| | - Kevin M. Krause
- Achaogen, One Tower Place, Suite 300, South San Francisco, California 94080, United States
| | - Gerard D. Wright
- M.G. DeGroote Institute for Infectious Disease Research, Department of Biochemistry and Biomedical Sciences, DeGroote School of Medicine, McMaster University, 1280 Main Street West, Hamilton, Ontario L8N 4K1, Canada
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Seyedi-Marghaki F, Kalantar-Neyestanaki D, Saffari F, Hosseini-Nave H, Moradi M. Distribution of Aminoglycoside-Modifying Enzymes and Molecular Analysis of the Coagulase Gene in Clinical Isolates of Methicillin-Resistant and Methicillin-Susceptible Staphylococcus aureus. Microb Drug Resist 2018; 25:47-53. [PMID: 29708846 DOI: 10.1089/mdr.2017.0121] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Enzymatic alteration of aminoglycosides by aminoglycoside-modifying enzymes (AMEs) is the major mechanism of resistance to aminoglycosides. The purpose of this study was to determine the frequency of AME genes, staphylococcal chromosomal cassette mec (SCCmec) types, and molecular analysis of the coagulase (coa) gene in Staphylococcus aureus strains isolated from clinical specimens. Totally, 102 S. aureus were tested by disk diffusion and microbroth dilution methods for susceptibility to aminoglycosides. AMEs genes and SCCmec types were determined by multiplex polymerase chain reaction (PCR). For polymorphism analysis, the 3' end region of the coa gene was amplified by PCR and the products were then subjected to restriction digestion with HaeIII enzyme. Of the 102 S. aureus, 42 (41.2%) were methicillin-resistant S. aureus (MRSA). Thirty-five (83%) of MRSA strains were resistant to kanamycin, 32 (76.2%) to tobramycin, 30 (71.4%) to gentamicin, 25 (59.5%) to amikacin, and 10 (23.8%) to netilmicin. The aac(6')-Ie-aph(2″) was the most frequent gene among MRSA isolates 19 (45.2%), followed by aph(3')-IIIa 8 (19%), ant(4')-Ia 6 (14.3%), and aph(2″)-Id 2 (4.8%). SCCmec types included type I 10 (23.8%), II 1 (2.4%), III 21 (50%), and IV 7 (16.7%). Three (7.2%) isolates were nontypeable. Digestion of the PCR products of the coa gene yielded 19 distinct restriction fragment length polymorphism patterns. In conclusion, given the alarming rate of resistance to aminoglycosides among MRSA, the monitoring of aminoglycoside resistance and AME genes should be performed to limit the spread of aminoglycoside resistance among MRSA isolates. Several variants of the coa gene were found in the studied isolates, although the majority of the MRSA isolates belonged to a limited number of coagulase types.
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Affiliation(s)
- Farhad Seyedi-Marghaki
- Department of Microbiology and Virology, School of Medicine, Kerman University of Medical Sciences , Kerman, Iran
| | - Davood Kalantar-Neyestanaki
- Department of Microbiology and Virology, School of Medicine, Kerman University of Medical Sciences , Kerman, Iran
| | - Fereshteh Saffari
- Department of Microbiology and Virology, School of Medicine, Kerman University of Medical Sciences , Kerman, Iran
| | - Hossein Hosseini-Nave
- Department of Microbiology and Virology, School of Medicine, Kerman University of Medical Sciences , Kerman, Iran
| | - Mohammad Moradi
- Department of Microbiology and Virology, School of Medicine, Kerman University of Medical Sciences , Kerman, Iran
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Cameron A, Klima CL, Ha R, Gruninger RJ, Zaheer R, McAllister TA. A Novel aadA Aminoglycoside Resistance Gene in Bovine and Porcine Pathogens. mSphere 2018; 3:e00568-17. [PMID: 29507894 DOI: 10.1128/mSphere.00568-17] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Accepted: 01/23/2018] [Indexed: 11/30/2022] Open
Abstract
Aminoglycosides are important antimicrobials used worldwide for prophylaxis and/or therapy in multiple production animal species. The emergence of new resistance genes jeopardizes current pathogen detection and treatment methods. The risk of resistance gene transfer to other animal and human pathogens is elevated when resistance genes are carried by mobile genetic elements. This study identified a new variant of a spectinomycin/streptomycin resistance gene harbored in a self-transmissible mobile element. The gene was also present in four different bovine pathogen species. A novel variant of the AAD(3″) class of aminoglycoside-modifying enzymes was discovered in fatal bovine respiratory disease-associated pathogens Pasteurella multocida and Histophilus somni. The aadA31 gene encodes a spectinomycin/streptomycin adenylyltransferase and was located in a variant of the integrative and conjugative element ICEMh1, a mobile genetic element transmissible among members of the family Pasteurellaceae. The gene was also detected in Mannheimia haemolytica from a case of porcine pneumonia and in Moraxella bovoculi from a case of keratoconjunctivitis. IMPORTANCE Aminoglycosides are important antimicrobials used worldwide for prophylaxis and/or therapy in multiple production animal species. The emergence of new resistance genes jeopardizes current pathogen detection and treatment methods. The risk of resistance gene transfer to other animal and human pathogens is elevated when resistance genes are carried by mobile genetic elements. This study identified a new variant of a spectinomycin/streptomycin resistance gene harbored in a self-transmissible mobile element. The gene was also present in four different bovine pathogen species.
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Fernández-Martínez M, Ruiz Del Castillo B, Lecea-Cuello MJ, Rodríguez-Baño J, Pascual Á, Martínez-Martínez L. Prevalence of Aminoglycoside-Modifying Enzymes in Escherichia coli and Klebsiella pneumoniae Producing Extended Spectrum β-Lactamases Collected in Two Multicenter Studies in Spain. Microb Drug Resist 2017; 24:367-376. [PMID: 29727265 DOI: 10.1089/mdr.2017.0102] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The in vitro activity of amikacin, gentamicin, kanamycin, tobramycin, neomycin, and netilmicin against 420 Escherichia coli producing extended spectrum β-lactamases (Ec-ESBLs) and 139 Klebsiella pneumoniae producing extended spectrum β-lactamase (Kp-ESBL) collected in two multicenter studies performed in Spain in 2000 and 2006 was determined. The presence of genes encoding aminoglycoside-modifying enzymes (AMEs) and 16S ribosomal RNA (rRNA) methylases [aac(3)-Ia, aac(3)-IIa, aac(3)-IVa, aac(6')-Ib, ant(2")-Ia, ant(4')-IIa, aph(3')-Ia, aph(3')-IIa, armA, rmtB, and rmtC] was also investigated. The resistance to (one or more) aminoglycosides was significantly higher in Kp-ESBL (104/139, 74.8%) than in Ec-ESBL (171/420, 40.7%; p < 0.0001). The lowest resistance rates for both species in the two studies were observed for amikacin. The prevalence of AME genes was significantly different in Ec-ESBL (161/420, 38.3%) than in Kp-ESBL (115/139, 82.7%; p < 0.0001). The most prevalent AME genes in Ec-ESBL and Kp-ESBL were aac(6')-Ib (16.2% and 44.6%) and aac(3)-IIa (14.7% and 43.1%), respectively. The expected phenotypic profile correlated with the found AMEs encoding genes in 59.6% Ec-ESBL and 26.1% Kp-ESBL. In Ec-ESBL, aac(6')-Ib was usually associated in 2000 with blaSHV (26.6%), but with blaCTX-M-1 group (34.8%) in 2006, while aac(3)-IIa was coincident in 2000 with blaTEM (14.6%) and with blaCTX-M-1 group (16.3%) in 2006. Among Kp-ESBL, the aac(6')-Ib and aac(3)-IIa genes were more frequent in strains with blaTEM (22.0% and 44.0%) in 2000 and with blaCTX-M-1 group (46.4% and 34.0%) in 2006. Resistance to aminoglycosides in Ec-ESBL and Kp-ESBL is frequent and related to production of AMEs; this limits the clinical use of aminoglycosides against these organisms.
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Affiliation(s)
- Marta Fernández-Martínez
- 1 Servicio de Microbiología, Hospital Universitario Marqués de Valdecilla , Santander, Spain .,2 Instituto de Investigación Marqués de Valdecilla (IDIVAL) , Santander, Spain
| | - Belén Ruiz Del Castillo
- 1 Servicio de Microbiología, Hospital Universitario Marqués de Valdecilla , Santander, Spain .,2 Instituto de Investigación Marqués de Valdecilla (IDIVAL) , Santander, Spain
| | - Maria Jesús Lecea-Cuello
- 1 Servicio de Microbiología, Hospital Universitario Marqués de Valdecilla , Santander, Spain .,2 Instituto de Investigación Marqués de Valdecilla (IDIVAL) , Santander, Spain
| | - Jesús Rodríguez-Baño
- 3 Unidad de Enfermedades Infecciosas y Microbiología Clínica, Hospital Universitario Virgen Macarena , Sevilla, Spain .,4 Departamento de Microbiología, Facultad de Medicina, Universidad de Sevilla , Sevilla, Spain .,5 Instituto de Biomedicina de Sevilla , IBiS/Hospital Universitario Virgen Macarena y Virgen del Rocío/CSIC/Universidad de Sevilla, Sevilla, Spain
| | - Álvaro Pascual
- 3 Unidad de Enfermedades Infecciosas y Microbiología Clínica, Hospital Universitario Virgen Macarena , Sevilla, Spain .,4 Departamento de Microbiología, Facultad de Medicina, Universidad de Sevilla , Sevilla, Spain .,5 Instituto de Biomedicina de Sevilla , IBiS/Hospital Universitario Virgen Macarena y Virgen del Rocío/CSIC/Universidad de Sevilla, Sevilla, Spain
| | - Luis Martínez-Martínez
- 6 Unidad de Gestión Clínica de Microbiología, Hospital Universitario Reina Sofía , Córdoba, Spain
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Ghotaslou R, Yeganeh Sefidan F, Akhi MT, Asgharzadeh M, Mohammadzadeh Asl Y. Dissemination of Genes Encoding Aminoglycoside-Modifying Enzymes and armA Among Enterobacteriaceae Isolates in Northwest Iran. Microb Drug Resist 2017; 23:826-832. [PMID: 28151044 DOI: 10.1089/mdr.2016.0224] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
INTRODUCTION Enzymatic inactivation is one of the most important mechanisms of resistance to aminoglycosides. The aim of this study was to investigate the prevalence of armA and diversity of the genes encoding aminoglycoside-modifying enzymes (AMEs) and their associations with resistance phenotypes in Enterobacteriaceae isolates. METHODS Three hundred and seven Enterobacteriaceae isolates were collected from five hospitals in northwest Iran. The disk diffusion method for amikacin, gentamicin, tobramycin, kanamycin, and streptomycin, as well as the minimum inhibitory concentration for amikacin, gentamicin, tobramycin, and kanamycin were done for susceptibility testing. Thirteen AME genes and armA methylase were screened using the PCR and sequencing assays. RESULTS Two hundred and twenty (71.7%) of isolates were resistant to aminoglycosides and 155 (70.5%) of them were positive for aminoglycoside resistance genes. The most prevalent AME genes were ant(3″)-Ia and aph(3″)-Ib with the frequency 35.9% and 30.5%, respectively. Also, 21 (9.5%) of resistant isolates were positive for armA methylase gene. CONCLUSIONS The prevalence of resistance to aminoglycoside is high and AME genes frequently are disseminated in Enterobacteriaceae isolates. There is an association between phenotypic resistance and the presence of some aminoglycoside genes.
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Affiliation(s)
- Reza Ghotaslou
- 1 Infectious and Tropical Diseases Research Center, Tabriz University of Medical Sciences , Tabriz, Iran .,2 Department of Microbiology, Faculty of Medicine, Tabriz University of Medical Sciences , Tabriz, Iran
| | - Fatemeh Yeganeh Sefidan
- 1 Infectious and Tropical Diseases Research Center, Tabriz University of Medical Sciences , Tabriz, Iran .,2 Department of Microbiology, Faculty of Medicine, Tabriz University of Medical Sciences , Tabriz, Iran
| | - Mohammad Taghi Akhi
- 2 Department of Microbiology, Faculty of Medicine, Tabriz University of Medical Sciences , Tabriz, Iran
| | - Mohammad Asgharzadeh
- 3 Department of Laboratory Sciences, Paramedical Faculty and Biotechnology Research Center, Tabriz University of Medical Sciences , Tabriz, Iran
| | - Yalda Mohammadzadeh Asl
- 2 Department of Microbiology, Faculty of Medicine, Tabriz University of Medical Sciences , Tabriz, Iran
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Michalska AD, Sacha PT, Ojdana D, Wieczorek A, Tryniszewska E. Prevalence of resistance to aminoglycosides and fluoroquinolones among Pseudomonas aeruginosa strains in a University Hospital in Northeastern Poland. Braz J Microbiol 2015; 45:1455-8. [PMID: 25763054 PMCID: PMC4323323 DOI: 10.1590/s1517-83822014000400041] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Accepted: 04/17/2014] [Indexed: 11/22/2022] Open
Abstract
The present study was conducted to investigate the prevalence of genes encoding resistance to aminoglycosides and fluoroquinolones among twenty-five Pseudomonas aeruginosa isolated between 2002 and 2009. In PCR, following genes were detected: ant(2″)-Ia in 9 (36.0%), aac(6')-Ib in 7 (28.0%), qnrB in 5 (20.0%), aph(3″)-Ib in 2 (8.0%) of isolates.
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Affiliation(s)
- Anna Diana Michalska
- Department of Microbiological Diagnostics and Infectious Immunology Medical University of Bialystok Poland Department of Microbiological Diagnostics and Infectious Immunology, Medical University of Bialystok, Poland
| | - Pawel Tomasz Sacha
- Department of Microbiological Diagnostics and Infectious Immunology Medical University of Bialystok Poland Department of Microbiological Diagnostics and Infectious Immunology, Medical University of Bialystok, Poland
| | - Dominika Ojdana
- Department of Microbiological Diagnostics and Infectious Immunology Medical University of Bialystok Poland Department of Microbiological Diagnostics and Infectious Immunology, Medical University of Bialystok, Poland
| | - Anna Wieczorek
- Department of Microbiological Diagnostics and Infectious Immunology Medical University of Bialystok Poland Department of Microbiological Diagnostics and Infectious Immunology, Medical University of Bialystok, Poland
| | - Elzbieta Tryniszewska
- Department of Microbiological Diagnostics and Infectious Immunology Medical University of Bialystok Poland Department of Microbiological Diagnostics and Infectious Immunology, Medical University of Bialystok, Poland
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Atasoy AR, Ciftci IH, Petek M. Modifying enzymes related aminoglycoside: analyses of resistant Acinetobacter isolates. Int J Clin Exp Med 2015; 8:2874-2880. [PMID: 25932248 PMCID: PMC4402895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Accepted: 02/06/2015] [Indexed: 06/04/2023]
Abstract
Enzymatic modification of aminoglycosides by nucleotidyltransferases, acetyltransferases and/or phosphotransferases accounts for the majority of aminoglycoside-resistant Acinetobacter isolates. In this study, we investigated the relationship between aminoglycoside resistance and the presence of aminoglycoside-modifying enzymes in Acinetobacter baumannii clinical isolate groups with different resistance profiles. Thirty-two clinical A. baumannii isolates were included in this study. Acinetobacter isolates were divided into 4 groups according to results of susceptibility testing. The presence of genes encoding the following aminoglycoside-modifying enzymes; aph (3')-V1, aph (3')-Ia, aac (3)-Ia, aac (3) IIa, aac (6')-Ih, aac (6')-Ib and ant (2')-Ia responsible for resistance was investigated by PCR in all strains. The acetyltransferase (aac (6')-Ib, aac (3)-Ia) and phosphotransferase (aph (3')-Ia) gene regions were identified in the first group, which comprised nine imipenem, meropenem, and gentamicin-resistant isolates. The acetyltransferase (aac (6')-Ib, aac (3)-Ia), phosphotransferase (aph (3')-VI) and nucleotidyltransferase (ant2-Ia) gene regions were identified in the second group, which was composed of nine imipenem-resistant, meropenem-resistant and gentamicin-sensitive isolates. The acetyltransferase (aac (3)-Ia) and phosphotransferase (aph (3')-Ia) regions were identified in the fourth group, which comprised eight imipenem-sensitive, meropenem-sensitive and gentamicin-resistant isolates. Modifying enzyme gene regions were not detected in the third group, which was composed of six imipenem, meropenem and gentamicin-sensitive isolates. Our data are consistent with previous reports, with the exception of four isolates. Both acetyltransferases and phosphotransferases were widespread in A. baumannii clinical isolates in our study. However, the presence of the enzyme alone is insufficient to explain the resistance rates. Therefore, the association between the development of resistance and the presence of the enzyme and other components should be investigated further.
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Affiliation(s)
- Ali Riza Atasoy
- Department of Medical Microbiology, Sakarya University Faculty of MedicineSakarya, Turkey
| | - Ihsan Hakki Ciftci
- Department of Medical Microbiology, Sakarya University Faculty of MedicineSakarya, Turkey
| | - Mustafa Petek
- Environmental Engineering, Fatih University Faculty of Engineeringİstanbul, Turkey
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