scholarly journals High Frequency of AdeA, AdeB and AdeC Genes among Acinetobacter baumannii Isolates

2020 ◽  
Author(s):  
Reza RANJBAR ◽  
Shahin ZAYERI ◽  
Davoud AFSHAR
Keyword(s):  
Acinetobacter Baumannii ◽  
Antimicrobial Agents ◽  
Susceptibility Testing ◽  
Efflux Pump ◽  
Multidrug Transporter ◽  
Efflux System ◽  
Pcr Assay ◽  
Multiplex Pcr Assay ◽  
High Prevalence ◽  
Imipenem Resistance

Background: Efflux pumps are involved in resistance of Acinetobacter baumannii isolates to antimicrobial agents. AdeABC efflux pump is one of the RND superfamily efflux pump and consists of adeA (membrane fusion), adeB (multidrug transporter) and adeC (outer membrane) genes. In this study, the frequency of adeA, adeB and adeC genes among A. baumannii isolates with resistance to erythromycin, trimethoprim, meropenem and imipenem was investigated. Methods: Overall, 79 strains of A. baumannii were isolated from patients admitted to two major hospitals in Tehran during 2016. Antibiotic susceptibility testing was determined by disc diffusion and microdilution methods according to Clinical and Laboratory Standards Institute (CLSI) guideline. The presence of adeA, adeB and adeC genes was also determined using Multiplex PCR assay. Results: The highest and the lowest resistance among A. baumannii isolates were to trimethoprim (93%) and erythromycin (53%), respectively. The frequency of adeA, adeB and adeC genes was 96.2%, 96.2% and 91.1 % respectively. There was a significant relationship between imipenem resistance and presence of efflux pump genes (P<0.05). Conclusion: According to the high prevalence of the AdeABC efflux system genes, it may involve in resistance of clinical isolates of A. baumannii to imipenem, especially.  

scholarly journals Functional Characterization of AbaQ, a Novel Efflux Pump Mediating Quinolone Resistance inAcinetobacter baumannii

2018 ◽  
Vol 62 (9) ◽  
Author(s):  
María Pérez-Varela ◽  
Jordi Corral ◽  
Jesús Aranda ◽  
Jordi Barbé
Keyword(s):  
Acinetobacter Baumannii ◽  
Antimicrobial Agents ◽  
Efflux Pump ◽  
Functional Characterization ◽  
Multidrug Resistant ◽  
Quinolone Resistance ◽  
Nosocomial Pathogen ◽  
Content Type ◽  
Mfs Transporter

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.

Development of multiplex PCR for rapid detection of metallo-β-lactamase genes in clinical isolates of Acinetobacter baumannii

2020 ◽  
Author(s):  
Reza Ranjbar ◽  
Shahin Zayeri ◽  
Amir Mirzaie
Keyword(s):  
Acinetobacter Baumannii ◽  
Multiplex Pcr ◽  
Rapid Detection ◽  
Simultaneous Detection ◽  
Cross Reactivity ◽  
Clinical Isolates ◽  
Clinical Samples ◽  
Pcr Assay ◽  
Multiplex Pcr Assay

Background and Objectives: Acinetobacter baumannii has been known as a major pathogen causing nosocomial infec- tions. The aim of this study was to develop multiplex PCR for rapid and simultaneous detection of metallo-β-lactamase (MBL) genes in clinical isolates of A. baumannii. Materials and Methods: In this study, we used three sets of primers to amplify the MBL genes including bla        ,     bla   and bla   OXA-48 . The multiplex PCR assay was optimized for rapid and simultaneous detection of MBL genes in A. bau-   OXA-23   NDM   mannii strains recovered from clinical samples. Results: A. baumannii strains recovered from clinical samples were subjected to the study. The multiplex PCR produced 3   OXA-48   OXA-23   bands of 501 bp for bla        , 744 bp for bla observed in multiplex PCR.   OXA-48   and 623 bp for bla   NDM   genes. In addition to, no any cross-reactivity was   Conclusion: Based on obtained data, the multiplex PCR had a good specificity without any cross reactivity and it appears that the multiplex PCR is reliable assay for simultaneous detection of MBL genes in A. baumannii strains.  

scholarly journals Rapid identification of Acinetobacter baumannii, Acinetobacter nosocomialis and Acinetobacter pittii with a multiplex PCR assay

2014 ◽  
Vol 63 (9) ◽  
pp. 1154-1159 ◽  
Author(s):  
Te-Li Chen ◽  
Yi-Tzu Lee ◽  
Shu-Chen Kuo ◽  
Su-Pen Yang ◽  
Chang-Phone Fung ◽  
...  
Keyword(s):  
Acinetobacter Baumannii ◽  
Multiplex Pcr ◽  
Acinetobacter Calcoaceticus ◽  
Rapid Identification ◽  
23S Rrna ◽  
Pcr Assay ◽  
Complex Species ◽  
Multiplex Pcr Assay ◽  
Acinetobacter Pittii ◽  
Reference Strains

Acinetobacter baumannii, Acinetobacter nosocomialis and Acinetobacter pittii are clinically relevant members of the Acinetobacter calcoaceticus–A. baumannii (Acb) complex and important nosocomial pathogens. These three species are genetically closely related and phenotypically similar; however, they differ in their epidemiology, antibiotic resistance and pathogenicity. In this study, we investigated the use of a multiplex PCR-based assay designed to detect internal fragments of the 16S–23S rRNA intergenic region and the gyrB and recA genes. The assay was capable of differentiating A. baumannii, A. nosocomialis and A. pittii in a reliable manner. In 23 different reference strains and 89 clinical isolates of Acinetobacter species, the assay accurately identified clinically relevant Acb complex species except those ‘between 1 and 3’ or ‘close to 13TU’. None of the non-Acb complex species was misidentified. In an analysis of 1034 positive blood cultures, the assay had a sensitivity of 92.4 % and specificity of 98.2 % for Acb complex identification. Our results show that a single multiplex PCR assay can reliably differentiate clinically relevant Acb complex species. Thus, this method may be used to better understand the clinical differences between infections caused by these species.

scholarly journals Pseudo-Outbreak of Imipenem-Resistant Acinetobacter baumannii Resulting from False Susceptibility Testing by a Rapid Automated System

2000 ◽  
Vol 38 (9) ◽  
pp. 3505-3507 ◽  
Author(s):  
Athanassios Tsakris ◽  
Anastassia Pantazi ◽  
Spyros Pournaras ◽  
Antonios Maniatis ◽  
Aleka Polyzou ◽  
...  
Keyword(s):  
Acinetobacter Baumannii ◽  
General Hospital ◽  
Susceptibility Testing ◽  
Homogeneous Group ◽  
Susceptibility Test ◽  
Automated System ◽  
Disk Diffusion ◽  
Broth Microdilution ◽  
High Prevalence ◽  
Agar Dilution

Introduction of the Vitek GNS-506 susceptibility testing cards in the Hippokration General Hospital, Thessaloniki, Greece, resulted in an apparently high prevalence of imipenem-resistant Acinetobacter baumannii. When 35 of these isolates were further tested by disk diffusion, broth microdilution, and agar dilution assays, 32 were imipenem sensitive by all tests and three were sensitive or intermediate, depending on the method. The pseudoresistant acinetobacters did not form a genetically homogeneous group. It is suggested that the detection of imipenem-resistant A. baumannii isolates by this system should be confirmed by an additional susceptibility test.

scholarly journals Characterization of AreABC, an RND-type efflux system involved in antimicrobial resistance of Aliarcobacter butzleri

2021 ◽  
Author(s):  
Susana Ferreira ◽  
Ana L. Silva ◽  
Joana Tomás ◽  
Cristiana Mateus ◽  
Fernanda Domingues ◽  
...  
Keyword(s):  
Antimicrobial Agents ◽  
Efflux Pump ◽  
Stop Codon ◽  
Premature Stop Codon ◽  
Efflux System ◽  
Erythromycin Resistance ◽  
Efflux Pump Inhibitor ◽  
Underlying Mechanisms ◽  
Multiple Drugs ◽  
Increased Susceptibility

Aliarcobacter butzleri is an emergent enteropathogen for which resistance to several classes of antimicrobial agents has been described, although the underlying mechanisms have been poorly addressed. We aimed to evaluate the contribution of the resistance-nodulation-division-type (RND) efflux system, AreABC, to drug resistance in A. butzleri . A. butzleri strains were first tested against several antimicrobials, with and without an efflux pump inhibitor. Then, erythromycin resistant strains were screened for the presence of a premature stop codon in a putative transcriptional regulator of the AreABC system, areR . Lastly, antimicrobial susceptibility and ethidium bromide (EtBr) accumulation were evaluated using an areB -knockout strain and a strain overexpressing the AreABC system through areR truncation. The presence of the efflux pump inhibitor resulted in increased susceptibility to most of the antimicrobials tested. A correlation between erythromycin resistance and the presence of premature stop codons in areR was observed. The truncation of areR resulted in increased expression of the AreABC system and decreased susceptibility to various antimicrobials. In contrast, areB inactivation resulted in increased susceptibility and a higher intracellular accumulation of EtBr. In conclusion, the AreABC efflux pump plays a role in the resistance of A. butzleri to multiple drugs and is regulated by a putative transcriptional repressor areR . Our results support the importance of efflux pumps in this bacterium's resistance to major classes of antibiotics and other antimicrobials.

scholarly journals Rescued chlorhexidine activity by resveratrol against carbapenem-resistant Acinetobacter baumannii via down-regulation of AdeB efflux pump

PLoS ONE ◽  
2020 ◽  
Vol 15 (12) ◽  
pp. e0243082
Author(s):  
Uthaibhorn Singkham-in ◽  
Paul G. Higgins ◽  
Dhammika Leshan Wannigama ◽  
Parichart Hongsing ◽  
Tanittha Chatsuwan
Keyword(s):  
Acinetobacter Baumannii ◽  
Ethidium Bromide ◽  
Antimicrobial Agents ◽  
Efflux Pump ◽  
Intracellular Accumulation ◽  
Efflux Pump Inhibitor ◽  
Carbapenem Resistant ◽  
Efflux Pump Inhibition ◽  
Synergistic Mechanism ◽  
Time Kill

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.

Role of ppGpp-regulated efflux genes in Acinetobacter baumannii

2020 ◽  
Vol 75 (5) ◽  
pp. 1130-1134 ◽  
Author(s):  
Hye-Won Jung ◽  
Kyeongmin Kim ◽  
M Maidul Islam ◽  
Je Chul Lee ◽  
Minsang Shin
Keyword(s):  
Acinetobacter Baumannii ◽  
Stress Responses ◽  
Pathogenic Bacteria ◽  
Antimicrobial Agents ◽  
Efflux Pump ◽  
Growth Control ◽  
Rational Drug Design ◽  
Transmission Electron Microscopy Analysis ◽  
Secondary Messenger ◽  
Electron Microscopy Analysis

Abstract Objectives Treatment of infections caused by Acinetobacter baumannii nosocomial strains has become increasingly problematic owing to their resistance to antibiotics. ppGpp is a secondary messenger involved in growth control and various stress responses in bacteria. The mechanism for inhibition of antibiotic resistance via ppGpp is still unidentified in various pathogenic bacteria including A. baumannii. Here, we investigated the effects of ppGpp on efflux pump (EP)-related genes in A. baumannii. Methods ppGpp-deficient and -complementary strains were constructed by conjugation and we confirmed (p)ppGpp measurements by thin-layer chromatography. We observed that the ppGpp-deficient strain (ΔA1S_0579) showed abnormal stretching patterns by transmission electron microscopy analysis. The MICs of antimicrobial agents for the WT A. baumannii (ATCC 17978), ppGpp-deficient and complementary strains were determined by the Etest and broth dilution assay methods. The expression levels of EP-related genes were determined by quantitative RT–PCR. Results We observed morphological differences between a ppGpp-deficient strain (ΔA1S_0579) and the WT strain. Dramatic reductions of MICs in the ppGpp-deficient strain compared with the WT were observed for gentamicin (2.6-fold), tetracycline (3.9-fold), erythromycin (4-fold) and trimethoprim (&gt;4-fold). Expression of the EP-related genes abeB (2.8-fold), tet(A) (2.3-fold), adeB (10.0-fold), adeI (9.9-fold), adeJ (11.8-fold) and adeK (14.4-fold) was also decreased in the ppGpp-deficient strain. Conclusions This study demonstrates that ppGpp regulates EP-related gene expression in A. baumannii, affecting antibiotic susceptibility. To date, treatment for MDR A. baumannii has had no new antimicrobial agents, so the A1S_0579 gene could be a novel therapeutic target for rational drug design by affecting ppGpp production.

scholarly journals Erythromycin and Clindamycin Resistance in Group B Streptococcal Clinical Isolates

2006 ◽  
Vol 50 (5) ◽  
pp. 1875-1877 ◽  
Author(s):  
Scott E. Gygax ◽  
Jessica A. Schuyler ◽  
Lauren E. Kimmel ◽  
Jason P. Trama ◽  
Eli Mordechai ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Resistance Genes ◽  
Susceptibility Testing ◽  
Antibiotic Resistance Genes ◽  
Clinical Isolates ◽  
Pcr Assay ◽  
Multiplex Pcr Assay ◽  
Disk Diffusion Assay ◽  
Group B ◽  
Diffusion Assay

ABSTRACT Erythromycin (EM) and clindamycin (CM) susceptibility testing was performed on 222 clinical isolates of group B Streptococcus. A multiplex PCR assay was used to detect the ermB, ermTR, and mefA/E antibiotic resistance genes. These results were compared to the phenotypes as determined by the standard EM/CM double disk diffusion assay.

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.

scholarly journals Role of AbeS, a Novel Efflux Pump of the SMR Family of Transporters, in Resistance to Antimicrobial Agents in Acinetobacter baumannii

2009 ◽  
Vol 53 (12) ◽  
pp. 5312-5316 ◽  
Author(s):  
Vijaya Bharathi Srinivasan ◽  
Govindan Rajamohan ◽  
Wondwossen A. Gebreyes
Keyword(s):  
Escherichia Coli ◽  
Acinetobacter Baumannii ◽  
Antimicrobial Agents ◽  
Efflux Pump ◽  
Multidrug Resistant ◽  
Drug Efflux ◽  
Drug Efflux Pump ◽  
Resistance Expression ◽  
Multidrug Resistant Strain

ABSTRACT In this study, a chromosomally encoded putative drug efflux pump of the SMR family, named AbeS, from a multidrug-resistant strain of Acinetobacter baumannii was characterized to elucidate its role in antimicrobial resistance. Expression of the cloned abeS gene in hypersensitive Escherichia coli host KAM32 resulted in decreased susceptibility to various classes of antimicrobial agents, detergents, and dyes. Deletion of the abeS gene in A. baumannii confirmed its role in conferring resistance to these compounds.

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