scholarly journals Aminoglycoside resistance mediated by the bifunctional enzyme 6 -N-aminoglycoside acetyltransferase-2 -O-aminoglycoside phosphotransferase

10.2741/a407 ◽  
1999 ◽  
Vol 4 (4) ◽  
pp. d1-8 ◽  
Author(s):  
José L Martínez
Keyword(s):  
Bifunctional Enzyme ◽  
Aminoglycoside Resistance ◽  
Aminoglycoside Phosphotransferase

scholarly journals Aminoglycoside Resistance in Mycobacterium kansasii,Mycobacterium avium-M. intracellulare, andMycobacterium fortuitum: Are Aminoglycoside-Modifying Enzymes Responsible?

2000 ◽  
Vol 44 (1) ◽  
pp. 39-42 ◽  
Author(s):  
I. I. Y. Ho ◽  
C. Y. Chan ◽  
A. F. B. Cheng
Keyword(s):  
Mycobacterium Avium ◽  
Substrate Affinity ◽  
Mycobacterium Kansasii ◽  
Mycobacterial Species ◽  
Aminoglycoside Resistance ◽  
Resistance Level ◽  
Positive Correlation ◽  
Aminoglycoside Phosphotransferase ◽  
Drug Modification

ABSTRACT Aminoglycoside acetyltransferase was detected inMycobacterium kansasii and M. fortuitum but not in M. avium-M. intracellulare when they were screened by a radioassay. Aminoglycoside phosphotransferase and nucleotidyltransferase activities were absent from all three species tested. Acetyltransferases from both M. kansasiiand M. fortuitum displayed relatively highKm s, all at the millimolar level, for substrates including tobramycin, neomycin, and kanamycin A. TheKm of each substrate was well above the corresponding maximum achievable level in serum. The low affinities of these enzymes for their substrates suggested that drug modification in vivo was very unlikely. Among the various substrates tested, no apparent positive correlation was found between substrate affinity and resistance level. The presence of aminoglycoside-modifying enzymes in these mycobacterial species was therefore not shown to confer resistance to aminoglycosides.

scholarly journals Aph(3′)-IIc, an Aminoglycoside Resistance Determinant from Stenotrophomonas maltophilia

2006 ◽  
Vol 51 (1) ◽  
pp. 359-360 ◽  
Author(s):  
Aki Okazaki ◽  
Matthew B. Avison
Keyword(s):  
Escherichia Coli ◽  
Clinical Isolate ◽  
Stenotrophomonas Maltophilia ◽  
Resistance Determinant ◽  
Aminoglycoside Resistance ◽  
Aminoglycoside Phosphotransferase

ABSTRACT We report the characterization of an intrinsic, chromosomally carried aph(3′)-IIc gene from Stenotrophomonas maltophilia clinical isolate K279a, encoding an aminoglycoside phosphotransferase enzyme that significantly increases MICs of kanamycin, neomycin, butirosin, and paromomycin when expressed in Escherichia coli. Disruption of aph(3′)-IIc in K279a results in decreased MICs of these drugs.

scholarly journals Cloning and Expression of Novel Aminoglycoside Phosphotransferase Genes from Campylobacter and Their Role in the Resistance to Six Aminoglycosides

2017 ◽  
Vol 62 (1) ◽  
Author(s):  
S. Zhao ◽  
S. Mukherjee ◽  
C. Li ◽  
S. B. Jones ◽  
S. Young ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Cloning And Expression ◽  
Aminoglycoside Resistance ◽  
Content Type ◽  
E Coli ◽  
Aminoglycoside Phosphotransferase

ABSTRACT Nine aph genes, including aph(2″)-Ib, aph(2″)-Ic, aph(2″)-Ig, aph(2″)-If, aph(2″)-If1, aph(2″)-If3, aph(2″)-Ih, aac(6′)-Ie–aph(2″)-Ia, and aac(6′)-Ie–aph(2″)-If2, were previously identified in Campylobacter. To measure the contribution of these alleles to aminoglycoside resistance, we cloned nine genes into the pBluescript and expressed them in Escherichia coli DH5α. The nine aph expressed in E. coli showed various levels of resistance to gentamicin, kanamycin, and tobramycin. Three genes, aac(6″)-Ie–aph(2″)-Ia, aph2″-If1, and aph2″-Ig, showed increased MICs to amikacin, and five aph genes were transferrable.

scholarly journals Diverse Aminoglycoside Phosphotransferase Types Conferring Aminoglycoside Resistance in Enterobacteriaceae: A Single-centre Study from Northeast India

2019 ◽  
Vol 37 (3) ◽  
pp. 418-423
Author(s):  
Jayalaxmi Wangkheimayum ◽  
Mohana Bhattacharjee ◽  
Bhaskar Jyoti Das ◽  
K.Melson Singha ◽  
Debadatta Dhar Chanda ◽  
...  
Keyword(s):  
Northeast India ◽  
Single Centre ◽  
Aminoglycoside Resistance ◽  
Centre Study ◽  
Aminoglycoside Phosphotransferase ◽  
Single Centre Study

scholarly journals Structure of the bifunctional aminoglycoside-resistance enzyme AAC(6′)-Ie-APH(2′′)-Ia revealed by crystallographic and small-angle X-ray scattering analysis

2014 ◽  
Vol 70 (10) ◽  
pp. 2754-2764 ◽  
Author(s):  
Clyde A. Smith ◽  
Marta Toth ◽  
Thomas M. Weiss ◽  
Hilary Frase ◽  
Sergei B. Vakulenko
Keyword(s):  
Small Angle ◽  
Coenzyme A ◽  
Full Length ◽  
Scattering Data ◽  
Bifunctional Enzyme ◽  
Aminoglycoside Resistance ◽  
X Ray ◽  
X Ray Scattering ◽  
Α Helix ◽  
Ray Scattering

Broad-spectrum resistance to aminoglycoside antibiotics in clinically important Gram-positive staphylococcal and enterococcal pathogens is primarily conferred by the bifunctional enzyme AAC(6′)-Ie-APH(2′′)-Ia. This enzyme possesses an N-terminal coenzyme A-dependent acetyltransferase domain [AAC(6′)-Ie] and a C-terminal GTP-dependent phosphotransferase domain [APH(2′′)-Ia], and together they produce resistance to almost all known aminoglycosides in clinical use. Despite considerable effort over the last two or more decades, structural details of AAC(6′)-Ie-APH(2′′)-Ia have remained elusive. In a recent breakthrough, the structure of the isolated C-terminal APH(2′′)-Ia enzyme was determined as the binary Mg2GDP complex. Here, the high-resolution structure of the N-terminal AAC(6′)-Ie enzyme is reported as a ternary kanamycin/coenzyme A abortive complex. The structure of the full-length bifunctional enzyme has subsequently been elucidated based upon small-angle X-ray scattering data using the two crystallographic models. The AAC(6′)-Ie enzyme is joined to APH(2′′)-Ia by a short, predominantly rigid linker at the N-terminal end of a long α-helix. This α-helix is in turn intrinsically associated with the N-terminus of APH(2′′)-Ia. This structural arrangement supports earlier observations that the presence of the intact α-helix is essential to the activity of both functionalities of the full-length AAC(6′)-Ie-APH(2′′)-Ia enzyme.

scholarly journals Healthcare-Associated Laboratory-Confirmed Bloodstream Infections—Species Diversity and Resistance Mechanisms, a Four-Year Retrospective Laboratory-Based Study in the South of Poland

2021 ◽  
Vol 18 (5) ◽  
pp. 2785
Author(s):  
Agnieszka Chmielarczyk ◽  
Monika Pomorska-Wesołowska ◽  
Dorota Romaniszyn ◽  
Jadwiga Wójkowska-Mach
Keyword(s):  
Bloodstream Infections ◽  
Diagnostic Techniques ◽  
Resistance Mechanisms ◽  
Infection Prevention And Control ◽  
The South ◽  
Coagulase Negative Staphylococci ◽  
Aminoglycoside Resistance ◽  
Gram Negative ◽  
Maldi Tof ◽  
Carbapenem Resistant

Introduction: Regardless of the country, advancements in medical care and infection prevention and control of bloodstream infections (BSIs) are an enormous burden of modern medicine. Objectives: The aim of our study was to describe the epidemiology and drug-resistance of laboratory-confirmed BSI (LC-BSIs) among adult patients of 16 hospitals in the south of Poland. Patients and methods: Data on 4218 LC-BSIs were collected between 2016–2019. The identification of the strains was performed using MALDI-TOF. Resistance mechanisms were investigated according to European Committee on Antimicrobial Susceptibility Testing, EUCAST recommendations. Results: Blood cultures were collected from 8899 patients, and LC-BSIs were confirmed in 47.4%. The prevalence of Gram-positive bacteria was 70.9%, Gram-negative 27.8% and yeast 1.4%. The most frequently isolated genus was Staphylococcus (50% of all LC-BSIs), with a domination of coagulase-negative staphylococci, while Escherichia coli (13.7%) was the most frequent Gram-negative bacterium. Over 4 years, 108 (2.6%) bacteria were isolated only once, including species from the human microbiota as well as environmental and zoonotic microorganisms. The highest methicillin resistant Staphylococcus aureus (MRSA) prevalence was in intensive care units (ICUs) (55.6%) but S. aureus with resistance to macrolides, lincosamides and streptogramins B (MLSB) in surgery was 66.7%. The highest prevalence of E. faecalis with a high-level aminoglycoside resistance (HLAR) mechanism was in ICUs, (84.6%), while E. faecium-HLAR in surgery was 83.3%. All cocci were fully glycopeptide-sensitive. Carbapenem-resistant Gram-negative bacilli were detected only in non-fermentative bacilli group, with prevalence 70% and more. Conclusions: The BSI microbiology in Polish hospitals was similar to those reported in other studies, but the prevalence of MRSA and enterococci-HLAR was higher than expected, as was the prevalence of carbapenem-resistant non-fermentative bacilli. Modern diagnostic techniques, such as MALDI-TOF, guarantee reliable diagnosis.

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