scholarly journals Characteristics of Quinolone Resistance in Multidrug-resistant Acinetobacter baumannii Strains Isolated from General Hospitals

2021 ◽  
Vol 14 (3) ◽  
Author(s):  
Choong Ki Hong ◽  
Joon Kim ◽  
Ga-Yeon Kim

Background: Acinetobacter baumannii is the causative agent in various types of hospital-acquired infections, including respiratory, urinary tract, and wound infections. Objectives: This study investigated the primary mechanisms underlying quinolone resistance in A. baumannii strains, isolated from samples collected from general hospitals. Methods: Ninety-eight strains of A. baumannii were isolated from clinical specimens from general hospitals from 2017 – 2019. Antimicrobial susceptibility, efflux pump inhibition tests, multilocus sequence typing (MLST), and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry analyses were conducted on 64 strains, and the blaoxa-51-like gene sequence was detected. Results: In the antimicrobial susceptibility test, 78.1% (n = 50) of the strains exhibited resistance to ciprofloxacin, a quinolone antibiotic, and 57.8% (n = 37) strains were multidrug resistant (MDR). For 18 strains, the minimum inhibitory concentration of ciprofloxacin reduced in presence of an efflux pump inhibitor. Sequence analysis revealed that in 50 strains of A. baumannii, the codon for serine (TCA) in gyrA was replaced by that for leucine (TTA), whereas in 43 strains, the codon for serine (TCG) in parC was replaced by that for leucine (TTG). Multilocus sequence typing analysis confirmed 18 sequence types, and allelic number analysis showed the presence of nine gyrB alleles, with gyrB3 showing the highest frequency (62.5%). Conclusions: The findings of this study will be useful in improving treatment efficiency and preventing the spread of A. baumannii (both MDR and non-MDR strains).

2018 ◽  
Vol 62 (9) ◽  
Author(s):  
María Pérez-Varela ◽  
Jordi Corral ◽  
Jesús Aranda ◽  
Jordi Barbé

ABSTRACTAcinetobacter baumanniihas emerged as an important multidrug-resistant nosocomial pathogen. In previous work, we identified a putative MFS transporter, AU097_RS17040, involved in the pathogenicity ofA. baumannii(M. Pérez-Varela, J. Corral, J. A. Vallejo, S. Rumbo-Feal, G. Bou, J. Aranda, and J. Barbé, Infect Immun 85:e00327-17, 2017,https://doi.org/10.1128/IAI.00327-17). In this study, we analyzed the susceptibility to diverse antimicrobial agents ofA. baumanniicells defective in this transporter, referred to as AbaQ. Our results showed that AbaQ is mainly involved in the extrusion of quinolone-type drugs inA. baumannii.


PLoS ONE ◽  
2020 ◽  
Vol 15 (12) ◽  
pp. e0243082
Author(s):  
Uthaibhorn Singkham-in ◽  
Paul G. Higgins ◽  
Dhammika Leshan Wannigama ◽  
Parichart Hongsing ◽  
Tanittha Chatsuwan

The aim of this study was to determine the activity and synergistic mechanisms of resveratrol in combination with chlorhexidine against carbapenem-resistant Acinetobacter baumannii clinical isolates. The activity of resveratrol plus antimicrobial agents was determined by checkerboard and time-kill assay against carbapenem-resistant A. baumannii isolated from patients at the King Chulalongkorn Memorial Hospital, Bangkok, Thailand. Overexpression of efflux pumps that mediates chlorhexidine susceptibility was characterized by the ethidium bromide accumulation assay. The effect of resveratrol on the expression of efflux pump genes (adeB, adeJ, adeG abeS, and aceI) and the two-component regulators, adeR and adeS was determined by RT-qPCR. The combination of resveratrol and chlorhexidine resulted in strong synergistic and bactericidal activity against carbapenem-resistant A. baumannii. Up-regulation of adeB and aceI was induced by chlorhexidine. However, the addition of resveratrol increased chlorhexidine susceptibility with increased intracellular accumulation of ethidium bromide in A. baumannii indicating that resveratrol acts as an efflux pump inhibitor. Expression of adeB was significantly reduced in the combination of resveratrol with chlorhexidine indicating that resveratrol inhibits the AdeB efflux pump and restores chlorhexidine effect on A. baumannii. In conclusion, reduced adeB expression in A. baumannii was mediated by resveratrol suggesting that AdeB efflux pump inhibition contributes to the synergistic mechanism of resveratrol with chlorhexidine. Our finding highlights the potential importance of resveratrol in clinical applications.


2018 ◽  
Vol 11 (4) ◽  
pp. 371-378 ◽  
Author(s):  
In-Sun Choi ◽  
Choon-Mee Kim ◽  
Sook-Jin Jang

AbstractBackgroundUnderstanding the contribution of efflux pumps to the resistance of antibiotics is useful when considering strategies for antimicrobial therapy.ObjectivesTo assess the role of efflux activity on the resistance of antibiotics commonly used in hospitals.MethodsWe analyzed the efflux activity of 120 clinical isolates of Acinetobacter baumannii using an Hoechst 33342 (H33342) dye-accumulation assay. We compared the indicators for efflux activity of susceptible and non-susceptible groups of each of 16 tested antibiotics. To determine the role of efflux activity on resistance to an antibiotic, we used 3 criteria based on the results of the H33342-accumulation assay.ResultsThe evaluation suggests that efflux activity contributed to resistance to the following 11 antibiotics: cefepime, cefotaxime, ceftazidime, ciprofloxacin, gentamicin, imipenem, meropenem, piperacillin, piperacillin/tazobactam, ticarcillin/ clavulanic acid, and tigecycline. However, ampicillin/sulbactam, minocycline, and trimethoprim/sulfamethoxazole did not meet the criteria, suggesting resistance may not be mediated by efflux activity. A significant difference in efflux activity was observed between bacteria belonging to the multidrug-resistant Acinetobacter baumannii (MDRAB) group and those belonging to the non-MDRAB group.ConclusionsEfflux activity may contribute to multidrug resistance and particularly resistance to numerous antibiotics used in hospitals. These antibiotics would be good candidates for combination therapeutic regimens consisting of an antibiotic and an efflux pump inhibitor as an adjuvant to combat drug efflux.


2021 ◽  
Vol 4 (9) ◽  
pp. 9799-9810
Author(s):  
Ioanna Eleftheriadou ◽  
Kleoniki Giannousi ◽  
Efthymia Protonotariou ◽  
Lemonia Skoura ◽  
Minas Arsenakis ◽  
...  

Author(s):  
Zumaana Rafiq ◽  
Sreevidya Narasimhan ◽  
Magesh Haridoss ◽  
Rosy Vennila ◽  
Rama Vaidyanathan

ABSTRACTObjective: With a rise in multidrug resistant (MDR) bacterial isolates, search for antibiotics or compounds that could act synergistically with themis a significant area of research. Efflux-mediated resistance, in particular, is a great hurdle that needs to be overcome. In an effort to identify suchsynergistic compounds and potential efflux pump inhibitors (EPI), we analyzed the rind of Punica granatum (pomegranate) against MDR clinicalKlebsiella pneumoniae isolates.Methods: Sequential fractionation of P. granatum rind ethanol (PGR) extract was carried out to obtain hexane, butanol and water fractions.Antibacterial activity of the plant extracts was confirmed, and synergistic interaction with antibiotics was determined by the checkerboard assay. Gaschromatography-mass spectrometry (GC-MS) analysis was performed to identify the phytochemical constituents of the hexane extract. To study EPIactivity of the extracts, norfloxacin accumulation assay was carried out.Results: PGR ethanol extract was found to have synergistic activity with ciprofloxacin, levofloxacin, ceftazidime, cefoxitin, meropenem, and gentamicinresulting in fold decrease of minimum inhibitory concentration (MIC) ranging from 2 to 32 fold. The hexane fraction was found to have maximumsynergistic activity resulting in a 32-fold reduction of ciprofloxacin MIC followed by butanol and water fractions. The PGR ethanol extract was alsofound to have efflux inhibition activity by the norfloxacin accumulation assay. Of the sequential fractions, the butanol fraction had maximum effluxinhibition activity.Conclusion: Therefore, our study shows that PGR extract can potentiate the effect of antibiotics on MDR bacteria, and the mode of action is likely tobe due to EPI.Keywords: Punica granatum rind, Pomegranate, Synergy with antibiotics, Multidrug resistant, Klebsiella pneumoniae, Efflux pump inhibition.


2020 ◽  
pp. 59-67
Author(s):  
Sulaiman D. Sulaiman ◽  
Ghusoon A. Abdulhasan

  Pseudomonas aeruginosa is considered as a developing opportunistic nosocomial pathogen and is well-known for its multidrug resistance that can be efficiently treated by a combination of antibiotics andefflux pump inhibitors (EPI). Therefore, the purpose of this study was to investigate the effect of curcumin as an EPI for the enhancement of the effectiveness of antibiotics against multidrug resistant (MDR) isolates ofP. aeruginosa. Susceptibility patterns of suspected bacteria was determined using the disc diffusion method andresistant bacteria were identified using chromogenic agar and 16S rDNA. The effectsof curcuminon the enhancement of antibiotics’s activity was evaluated usingthe broth microdilution method.The susceptibility patterns for 50 (67.6%) suspectedP. aeruginosaisolates showed that 36 (72%) of these isolateswere resistant to one of the used antibiotics,whereasonly 21 (42%) were MDR. The highest percentage of resistance was observedtoceftazidime (66%) followed by ciprofloxacin and levofloxacin (40%). Only 35 isolates were specified by chromogenic agar and 16S rDNAas P. aeruginosa.The minimal inhibitory concentration (MIC) of 35 isolates for ciprofloxacin resistant was between 4 and128 µg/ml while for ceftazidime was between 64and 512 µg/ml. After the addition of 50 μg/ml curcumin with ciprofloxacin, there wasa significant increase in the sensitivity (p≤ 0.01) of 13 MDR P.aeroginosa isolates whereas no differences in the sensitivity to ceftazidime were recorded before and after addition ofcurcumin. In conclusion, the results of this study show that curcumin can decrease the MIC value of ciprofloxacin in MDR isolates of P. aeruginosaand can be used as a native compound to enhance the treatment of resistant isolates with ciprofloxacin.


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