Related Experiment Videos
Active efflux pump adeB is involved in multidrug resistance of Acinetobacter baumannii induced by antibacterial
Tingting Zhang1, Min Wang1, Yixin Xie1
1Department of Laboratory Medicine, The Second Xiangya Hospital, Central South University, Changsha, Hunan 410011, P.R. China.
Abstract:
The aim of the present study was to investigate the resistance of Acinetobacter baumannii, which was induced by cefepime (FEP), cefoperazone-sulbactam (SCF), tazobactam (TZP), levofloxacin (LEV), amikacin (AK), imipenem (IPM), and ciprofloxacin (CIP), in vitro. Multi-step drug resistance selection of 16 A. baumannii strains was performed using seven antibacterial agents (FEP, TZP, CIP, AK, IPM, SCF, and LEV). The minimum inhibitory concentration (MIC) was determined using the agar dilution method. Random amplified polymorphic DNA polymerase chain reaction was performed to analyze the genotypes and the carrying rates of aac(3)-I, aac(6')-I, ant(3)-I, aph(3)-Via, OXA-23, OXA-24, AmpC, TEM-1, metallo-β-lactamase gene (IMP), armA, rmtA, rmtB, parC, gyrA and adeB. Expression of adeB was determined using semi-quantitative reverse transcription-polymerase chain reaction (Semi-qRT-PCR). Among the 16 strains, 15 strains with drug resistance (93.8%) were obtained following in vitro induction. Notable increases (8- to 128-fold) were noted in the MIC and different genotypes were showed in RAPD of the strains before and after performing the drug resistant test. PCR data revealed significant differences (P<0.05) between the carrying rates of resistant genes before and after drug induction, with the exception of rmtA, OXA-24, TEM-1, and IMP. Significant increases were demonstrated in the comparative adeB grayscale in strains that underwent drug induction when compared with the sensitive strains (55.69±43.11% vs. 10.08±26.35%; P=0.001). Findings of the present study suggest that the active efflux pump, adeB, has an important role in multidrug resistance of the A. baumannii induced by antibacterial agents in vitro.
Insights
This study shows that the efflux pump adeB plays a key role in Acinetobacter baumannii developing resistance to antibiotics like cefepime and ciprofloxacin in vitro. Increased adeB expression significantly contributes to multidrug resistance.
Area of Science:
- Microbiology
- Molecular Biology
- Pharmacology
Background:
- Acinetobacter baumannii is a significant opportunistic pathogen.
- Antibiotic resistance in A. baumannii poses a major global health threat.
- Understanding resistance mechanisms is crucial for developing effective treatments.
Purpose of the Study:
- To investigate the in vitro induction of antibiotic resistance in Acinetobacter baumannii.
- To identify genetic changes associated with acquired drug resistance.
- To determine the role of the adeB efflux pump in multidrug resistance.
Main Methods:
- Multi-step drug resistance selection using seven antibiotics.
- Determination of minimum inhibitory concentrations (MIC) via agar dilution.
- Genotyping using Random Amplified Polymorphic DNA (RAPD) PCR.
- Analysis of resistance gene carriage rates.
- Quantification of adeB gene expression using semi-quantitative RT-PCR.
Main Results:
- 15 out of 16 A. baumannii strains (93.8%) acquired drug resistance after in vitro induction.
- Significant increases in MIC (8- to 128-fold) and changes in RAPD genotypes were observed.
- Carrying rates of most resistance genes differed significantly before and after induction (P<0.05).
- A significant increase in adeB expression was found in induced resistant strains compared to sensitive strains (55.69% vs. 10.08%, P=0.001).
Conclusions:
- In vitro induction effectively generates multidrug-resistant Acinetobacter baumannii strains.
- The adeB efflux pump is significantly upregulated and plays a critical role in acquired multidrug resistance.
- These findings highlight the importance of targeting efflux pumps to combat A. baumannii infections.