scholarly journals Effect of Phenylalanine-arginine-beta-naphthylamide to Ciprofloxacin Minimum Inhibitory Concentration Values and Expression of Efflux Pump System Genes in Acinetobacter baumannii Isolates

2021 ◽  
Vol 55 (3) ◽  
pp. 285-299
Author(s):  
Fatma Kaynak Onurdağ ◽  
Uğur Kayış ◽  
Suzan Ökten
Keyword(s):  
Minimum Inhibitory Concentration ◽  
Acinetobacter Baumannii ◽  
Inhibitory Concentration ◽  
Efflux Pump ◽  
Pump System

scholarly journals Efflux Pump Activity and Mutations Driving Multidrug Resistance in Acinetobacter baumannii at a Tertiary Hospital in Pretoria, South Africa

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Noel-David Nogbou ◽  
Granny M. Nkawane ◽  
Khanyisa Ntshane ◽  
Charles K. Wairuri ◽  
Dikwata T. Phofa ◽  
...  
Keyword(s):  
Acinetobacter Baumannii ◽  
Gene Mutation ◽  
Efflux Pump ◽  
Pcr Amplification ◽  
Tertiary Hospital ◽  
Gyra Gene ◽  
Efflux Pump Inhibitor ◽  
Pump System ◽  
Mechanism Of Resistance ◽  
Evolutionary Relatedness

Acinetobacter baumannii (A. baumannii) has developed several resistance mechanisms. The bacteria have been reported as origin of multiple outbreaks. This study aims to investigate the use of efflux pumps and quinolone resistance-associated genotypic mutations as mechanisms of resistance in A. baumannii isolates at a tertiary hospital. A total number of 103 A. baumannii isolates were investigated after identification and antimicrobial susceptibility testing by VITEK2 followed by PCR amplification of blaOXA-51. Conventional PCR amplification of the AdeABC efflux pump (adeB, adeS, and adeR) and quinolone (parC and gyrA) resistance genes were performed, followed by quantitative real-time PCR of AdeABC efflux pump genes. Phenotypic evaluation of efflux pump expression was performed by determining the difference between the MIC of tigecycline before and after exposure to an efflux pump inhibitor. The Sanger sequencing method was used to sequence the parC and gyrA amplicons. A phylogenetic tree was drawn using MEGA 4.0 to evaluate evolutionary relatedness of the strains. All the collected isolates were blaOXA-51-positive. High resistance to almost all the tested antibiotics was observed. Efflux pump was found in 75% of isolates as a mechanism of resistance. The study detected parC gene mutation in 60% and gyrA gene mutation in 85%, while 37% of isolates had mutations on both genes. A minimal evolutionary distance between the isolates was reported. The use of the AdeABC efflux pump system as an active mechanism of resistance combined with point mutation mainly in gyrA was shown to contribute to broaden the resistance spectrum of A. baumannii isolates.

scholarly journals Insights into the Resistome and Phylogenomics of a ST195 Multidrug-Resistant Acinetobacter baumannii Clinical Isolate from the Czech Republic

Life ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1079
Author(s):  
Patrik Mlynarcik ◽  
Monika Dolejska ◽  
Iva Vagnerova ◽  
Jana Petrzelova ◽  
Iva Sukkar ◽  
...  
Keyword(s):  
Acinetobacter Baumannii ◽  
Clinical Isolate ◽  
Efflux Pump ◽  
Resistance Mechanism ◽  
Carbapenem Resistance ◽  
Multidrug Resistant ◽  
Clinical Settings ◽  
Sequencing Analysis ◽  
Pump System ◽  
The Czech Republic

Increasing antimicrobial resistance in nosocomial pathogens, such as Acinetobacter baumannii, is becoming a serious threat to public health. It is necessary to detect β-lactamase-producing microorganisms in clinical settings to be able to control the spread of carbapenem resistance. This study was conducted to evaluate the presence of β-lactamases in a selected clinical isolate of A. baumannii of ST2P/ST195Ox and to characterize possible enzymes, as well as its β-lactam resistome, using PCR and whole-genome sequencing analysis. PCR and sequencing confirmed that the isolate harbored five bla gene alleles, namely, blaADC-73, blaTEM-1, blaOXA-23, blaOXA-58 and blaOXA-66, as well as aminoglycosides, macrolides, sulfonamides and tetracyclines resistance determinants, which were either chromosomally and/or plasmid located. Furthermore, a gene order comparison using MAUVE alignment showed multiple changes compared with the clinical isolate of Malaysian A. baumannii AC30 genome and 76 regions with high homology. This study suggests that resistance to β-lactams in this A. baumannii isolate is mainly due to an overproduction of β-lactamases in combination with other resistance mechanism (efflux pump system).

Synergistic Effect of Tazobactam on Amikacin MIC in Acinetobacter baumannii Isolated from Burn Patients in Tehran, Iran

2020 ◽  
Vol 21 (10) ◽  
pp. 997-1004
Author(s):  
Leila Azimi ◽  
Sahel V. Tahbaz ◽  
Reza Alaghehbandan ◽  
Farank Alinejad ◽  
Abdolaziz R. Lari
Keyword(s):  
Acinetobacter Baumannii ◽  
Inhibitory Concentration ◽  
Efflux Pump ◽  
Multidrug Resistant ◽  
Inhibitory Effect ◽  
Resistant Bacteria ◽  
High Morbidity ◽  
Burn Patients ◽  
Global Public Health ◽  
Before And After

Background: Burn is still an important global public health challenge. Wound colonization of antibiotic resistant bacteria such as Acinetobacter baumannii can lead to high morbidity and mortality in burn patients. The aim of this study was to evaluate the inhibitory effect of tazobactam on efflux pump, which can cause aminoglycoside resistant in A. baumannii isolated from burn patients. Methods: In this study, 47 aminoglycoside resistant A. baumannii spp. were obtained from burn patients, admitted to the Shahid Motahari Burns Hospital in Tehran, Iran, during June-August 2018. The inhibitory effect of tazobactam against adeB such as efflux pump was evaluated by Minimum Inhibitory Concentration (MIC) determination of amikacin alone and in combination with tazobactam. Fractional Inhibitory Concentration index (FIC) was used to determine the efficacy of tazobactam/ amikacin combination. Further, semi-quantitative Real- Time PCR was performed to quantify the expression rates of the adeB gene before and after addition of tazobactam/amikacin. Results: The MIC values were significantly reduced when a combined amikacin and tazobactam was utilized. The most common interaction observed was synergistic (78.2%), followed by additive effects (21.8%), as per FIC results. The adeB mRNA expression levels were found to be downregulated in 60.7% of isolates treated with tazobactam. Conclusions: Tazobactam can have impact on resistance to aminoglycoside by inhibiting efflux pump. Thus, the combination of tazobactam with amikacin can be used as an alternative treatment approach in multidrug resistant A. baumannii infections.

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