scholarly journals Active efflux pump adeB is involved in multidrug resistance of Acinetobacter baumannii induced by antibacterial agents

2017 ◽  
Vol 13 (4) ◽  
pp. 1538-1546 ◽  
Author(s):  
Tingting Zhang ◽  
Min Wang ◽  
Yixin Xie ◽  
Xianping Li ◽  
Zhihui Dong ◽  
...  
Keyword(s):  
Multidrug Resistance ◽  
Acinetobacter Baumannii ◽  
Antibacterial Agents ◽  
Efflux Pump ◽  
Active Efflux ◽  
Active Efflux Pump

scholarly journals Triclosan resistance in clinical isolates of Acinetobacter baumannii

2009 ◽  
Vol 58 (8) ◽  
pp. 1086-1091 ◽  
Author(s):  
Yagang Chen ◽  
Borui Pi ◽  
Hua Zhou ◽  
Yunsong Yu ◽  
Lanjuan Li
Keyword(s):  
Acinetobacter Baumannii ◽  
Efflux Pump ◽  
Resistance Mechanism ◽  
Dilution Method ◽  
Agar Dilution Method ◽  
Active Efflux ◽  
Low Level ◽  
High Level ◽  
Resistance Rates ◽  
Triclosan Resistance

The susceptibility to triclosan of 732 clinical Acinetobacter baumannii isolates obtained from 25 hospitals in 16 cities in China from December 2004 to December 2005 was screened by using an agar dilution method. Triclosan MICs ranged between 0.015 and 16 mg l−1, and the MIC90 was 0.5 mg l−1, lower than the actual in-use concentration of triclosan. Twenty triclosan-resistant isolates (MICs ≥1 mg l−1) were characterized by antibiotic susceptibility, clonal relatedness, fabI mutation, fabI expression, and efflux pump phenotype and expression to elucidate the resistance mechanism of A. baumannii to triclosan. The resistance rates of triclosan-resistant isolates to imipenem, levofloxacin, amikacin and tetracycline were higher than those of triclosan-sensitive isolates. Triclosan resistance was artificially classified as low level (MICs 1–2 mg l−1) or high level (MICs ≥4 mg l−1). High-level triclosan resistance could be explained by a Gly95Ser mutation of FabI, whilst wild-type fabI was observed to be overexpressed in low-level resistant isolates. Active efflux did not appear to be a major reason for acquired triclosan resistance, but acquisition of resistance appeared to be dependent on a background of intrinsic triclosan efflux.

scholarly journals Overexpression of Efflux Pumps, Mutations in the Pumps’ Regulators, Chromosomal Mutations, and AAC(6′)-Ib-cr Are Associated With Fluoroquinolone Resistance in Diverse Sequence Types of Neonatal Septicaemic Acinetobacter baumannii: A 7-Year Single Center Study

2021 ◽  
Vol 12 ◽  
Author(s):  
Subhasree Roy ◽  
Somdatta Chatterjee ◽  
Amrita Bhattacharjee ◽  
Pinaki Chattopadhyay ◽  
Bijan Saha ◽  
...  
Keyword(s):  
Acinetobacter Baumannii ◽  
Efflux Pump ◽  
Critical Role ◽  
Holistic Approach ◽  
Efflux Pumps ◽  
Resistance Mechanisms ◽  
Fluoroquinolone Resistance ◽  
Active Efflux ◽  
Chromosomal Mutations ◽  
Sequence Types

This study investigates susceptibility toward three fluoroquinolones (ciprofloxacin, levofloxacin, moxifloxacin), multiple fluoroquinolone-resistance mechanisms, and epidemiological relationship of neonatal septicaemic Acinetobacter baumannii. Previous studies on fluoroquinolone resistance in A. baumannii focused primarily on ciprofloxacin susceptibility and assessed a particular mechanism of resistance; a more holistic approach was taken here. Epidemiological relationship was evaluated by Multi Locus Sequence Typing. Minimum Inhibitory Concentrations of fluoroquinolones was determined with and without efflux pump inhibitors. Overexpression of efflux pumps, resistance-nodulation-cell-division (RND)-type, and multidrug and toxic compound extrusion (MATE)-type efflux pumps were evaluated by reverse transcriptase-qPCR. Mutations within regulatory proteins (AdeRS, AdeN, and AdeL) of RND-pumps were examined. Chromosomal mutations, presence of qnr and aac(6′)-Ib-cr were investigated. A. baumannii were highly diverse as 24 sequence-types with seven novel STs (ST-1440/ST-1441/ST-1481/ST-1482/ST-1483/ST-1484/ST-1486) were identified among 47 A. baumannii. High resistance to ciprofloxacin (96%), levofloxacin (92%), and particularly moxifloxacin (90%) was observed, with multiple mechanisms being active. Resistance to 4th generation fluoroquinolone (moxifloxacin) in neonatal isolates is worrisome. Mutations within GyrA (S83L) and ParC (S80L) were detected in more than 90% of fluoroquinolone-resistant A. baumannii (FQRAB) spread across 10 different clonal complexes (CC1/CC2/CC10/CC25/CC32/CC126/CC149/CC216/CC218/CC513). Efflux-based FQ resistance was found in 65% of FQRAB with ≥2 different active pumps in 38% of strains. Overexpression of adeB was highest (2.2−34-folds) followed by adeJ, adeG, and abeM. Amino acid changes in the regulators (AdeRS/AdeN/AdeL) either as single or multiple substitutions substantiated the overexpression of the pumps. Diverse mutations within AdeRS were detected among different CCs whereas mutations within AdeN linked to CC10 and CC32. Chromosomal mutations and active efflux pumps were detected simultaneously among 64% of FQRAB. Presence of aac(6′)-Ib-cr was also high (74% of FQRAB) but qnrS were absent. As most FQRABs had chromosomal mutations, this was considered predominant, however, isolates where pumps were also active had higher MIC values, establishing the critical role of the efflux pumps. The high variability of FQ susceptibility among FQRAB, possessing the same set of mutations in gyrA, parC, and efflux pump regulators, was also noted. This reveals the complexity of interpreting the interplay of multiple resistance mechanisms in A. baumannii.

scholarly journals Selenocompounds as Novel Antibacterial Agents and Bacterial Efflux Pump Inhibitors

Molecules ◽  
2019 ◽  
Vol 24 (8) ◽  
pp. 1487 ◽  
Author(s):  
Tímea Mosolygó ◽  
Annamária Kincses ◽  
Andrea Csonka ◽  
Ádám Szabó Tönki ◽  
Karolina Witek ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Multidrug Resistance ◽  
Carbonyl Compounds ◽  
Antibacterial Agents ◽  
Inhibitory Concentration ◽  
Efflux Pump ◽  
Attractive Potential ◽  
Bacterial Strains ◽  
Gram Positive Bacteria ◽  
Efflux Pump Inhibitors

Bacterial multidrug resistance is becoming a growing problem for public health, due to the development and spreading of bacterial strains resistant to antimicrobials. In this study, the antibacterial and multidrug resistance reversing activity of a series of seleno-carbonyl compounds has been evaluated. The effects of eleven selenocompounds on bacterial growth were evaluated in Staphylococcus aureus, methicillin resistant S. aureus (MRSA), Enterococcus faecalis, Escherichia coli, and Chlamydia trachomatis D. The combination effect of compounds with antibiotics was examined by the minimum inhibitory concentration reduction assay. Their efflux pump (EP) inhibitory properties were assessed using real-time fluorimetry. Relative expressions of EP and quorum-sensing genes were studied by quantitative PCR. Results showed that a methylketone selenoester had remarkable antibacterial activity against Gram-positive bacteria and potentiated the activity of oxacillin in MRSA. Most of the selenocompounds showed significant anti-chlamydial effects. The selenoanhydride and the diselenodiester were active inhibitors of the AcrAB-TolC system. Based on these results it can be concluded that this group of selenocompounds can be attractive potential antibacterials and EP inhibitors. The discovery of new derivatives with a significant antibacterial activity as novel selenocompounds, is of high impact in the fight against resistant pathogens.

scholarly journals First Identification and Characterization of an AdeABC-Like Efflux Pump inAcinetobacterGenomospecies 13TU

2011 ◽  
Vol 55 (3) ◽  
pp. 1285-1286 ◽  
Author(s):  
Ignasi Roca ◽  
Paula Espinal ◽  
Sara Martí ◽  
Jordi Vila
Keyword(s):  
Multidrug Resistance ◽  
Acinetobacter Baumannii ◽  
Clinical Isolate ◽  
Nosocomial Infections ◽  
Efflux Pump ◽  
Hospital Setting ◽  
Multidrug Resistant ◽  
Identification Techniques ◽  
Identification And Characterization

ABSTRACTNon-Acinetobacter baumanniispp. are emerging among clinicalAcinetobacterisolates causing nosocomial infections, and some (such as genomospecies 13TU) appear to be multidrug resistant. The prevalence of non-Acinetobacter baumanniispp. in the hospital setting is likely understated due to poor identification techniques. We report the first identification of an AdeABC-type efflux pump in anAcinetobactergenomospecies 13TU clinical isolate, its contribution to multidrug resistance, and the coexistence of three Ade-type efflux pumps in this strain.

scholarly journals CraA, a Major Facilitator Superfamily Efflux Pump Associated with Chloramphenicol Resistance in Acinetobacter baumannii

2009 ◽  
Vol 53 (9) ◽  
pp. 4013-4014 ◽  
Author(s):  
I. Roca ◽  
S. Marti ◽  
P. Espinal ◽  
P. Martínez ◽  
I. Gibert ◽  
...  
Keyword(s):  
Multidrug Resistance ◽  
Acinetobacter Baumannii ◽  
Antimicrobial Agents ◽  
Efflux Pump ◽  
Major Facilitator Superfamily ◽  
Intrinsic Resistance ◽  
Chloramphenicol Resistance ◽  
Hospital Acquired Infections ◽  
Major Facilitator ◽  
Hospital Acquired

ABSTRACT Acinetobacter baumannii has been increasingly associated with hospital-acquired infections, and the presence of multidrug resistance strains is of great concern to clinicians. A. baumannii is thought to possess a great deal of intrinsic resistance to several antimicrobial agents, including chloramphenicol, although the mechanisms involved in such resistance are not well understood. In this work, we have identified a major facilitator superfamily efflux pump present in most A. baumannii strains, displaying strong substrate specificity toward chloramphenicol.

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