scholarly journals Mutational Activation of Antibiotic Resistant Mechanisms in the Absence of Major Drug Efflux Systems of Escherichia coli

2021 ◽  
Author(s):  
Hyun Jae Cho ◽  
Rajeev Misra
Keyword(s):  
Escherichia Coli ◽  
Antibiotic Resistance ◽  
Efflux Pump ◽  
Efflux Pumps ◽  
Regulatory Genes ◽  
Health Concern ◽  
Missense Mutations ◽  
Compensatory Mutations ◽  
Mutational Activation ◽  
Antibiotic Efflux

Mutations are one of the common means by which bacteria acquire resistance to antibiotics. In an Escherichia coli mutant lacking major antibiotic efflux pumps AcrAB and AcrEF, mutations can activate alternative pathways that lead to increased antibiotic resistance. In this work, we isolated and characterized compensatory mutations of this nature mapping in four different regulatory genes—baeS, crp, hns, or rpoB. The gain-of-function mutations in baeS constitutively activated the BaeSR two-component regulatory system to increase the expression of the MdtABC efflux pump. The loss-of-function mutations in crp and hns caused de-repression of an operon coding for the MdtEF efflux pump. Interestingly, despite the dependence of rpoB missense mutations on MdtABC for their antibiotic resistance phenotype, neither the expression of the mdtABCDbaeSR operon nor that of other known antibiotic efflux pumps went up. Instead, the RNA-seq data revealed a gene expression profile resembling that of a “stringent” RNA polymerase where protein and DNA biosynthesis pathways were down-regulated, but pathways to combat various stresses were up-regulated. Some of these activated stress pathways are also controlled by the general stress sigma factor, RpoS. The data presented here also show that compensatory mutations can act synergistically to further increase antibiotic resistance to a level similar to the efflux pump-proficient parental strain. Together, the findings highlight a remarkable genetic ability of bacteria to circumvent antibiotic assault even in the absence of a major intrinsic antibiotic resistance mechanism. Importance Antibiotic resistance among bacterial pathogens is a chronic health concern. Bacteria possess or acquire various mechanisms of antibiotic resistance, and chief among them is the ability to accumulate beneficial mutations that often alter antibiotic targets. Here we explored E. coli’s ability to amass mutations in a background devoid of a major, constitutively expressed efflux pump and identified mutations in several regulatory genes that confer resistance by activating specific or pleiotropic mechanisms.

scholarly journals Expression of Pseudomonas aeruginosa Multidrug Efflux Pumps MexA-MexB-OprM and MexC-MexD-OprJ in a Multidrug-Sensitive Escherichia coli Strain

1998 ◽  
Vol 42 (1) ◽  
pp. 65-71 ◽  
Author(s):  
Ramakrishnan Srikumar ◽  
Tatiana Kon ◽  
Naomasa Gotoh ◽  
Keith Poole
Keyword(s):  
Escherichia Coli ◽  
Pseudomonas Aeruginosa ◽  
Antibiotic Resistance ◽  
Crystal Violet ◽  
Efflux Pump ◽  
Efflux Pumps ◽  
Multidrug Efflux ◽  
Efflux System ◽  
E Coli ◽  
Multidrug Efflux Pumps

ABSTRACT The mexCD-oprJ and mexAB-oprM operons encode components of two distinct multidrug efflux pumps inPseudomonas aeruginosa. To assess the contribution of individual components to antibiotic resistance and substrate specificity, these operons and their component genes were cloned and expressed in Escherichia coli. Western immunoblotting confirmed expression of the P. aeruginosa efflux pump components in E. coli strains expressing and deficient in the endogenous multidrug efflux system (AcrAB), although only the ΔacrAB strain, KZM120, demonstrated increased resistance to antibiotics in the presence of the P. aeruginosa efflux genes. E. coli KZM120 expressing MexAB-OprM showed increased resistance to quinolones, chloramphenicol, erythromycin, azithromycin, sodium dodecyl sulfate (SDS), crystal violet, novobiocin, and, significantly, several β-lactams, which is reminiscent of the operation of this pump in P. aeruginosa. This confirmed previous suggestions that MexAB-OprM provides a direct contribution to β-lactam resistance via the efflux of this group of antibiotics. An increase in antibiotic resistance, however, was not observed when MexAB or OprM alone was expressed in KZM120. Thus, despite the fact that β-lactams act within the periplasm, OprM alone is insufficient to provide resistance to these agents. E. coli KZM120 expressing MexCD-OprJ also showed increased resistance to quinolones, chloramphenicol, macrolides, SDS, and crystal violet, though not to most β-lactams or novobiocin, again somewhat reminiscent of the antibiotic resistance profile of MexCD-OprJ-expressing strains ofP. aeruginosa. Surprisingly, E. coli KZM120 expressing MexCD alone also showed an increase in resistance to these agents, while an OprJ-expressing KZM120 failed to demonstrate any increase in antibiotic resistance. MexCD-mediated resistance, however, was absent in a tolC mutant of KZM120, indicating that MexCD functions in KZM120 in conjunction with TolC, the previously identified outer membrane component of the AcrAB-TolC efflux system. These data confirm that a tripartite efflux pump is necessary for the efflux of all substrate antibiotics and that the P. aeruginosa multidrug efflux pumps are functional and retain their substrate specificity in E. coli.

scholarly journals Interplay between Efflux Pumps May Provide Either Additive or Multiplicative Effects on Drug Resistance

2000 ◽  
Vol 182 (11) ◽  
pp. 3142-3150 ◽  
Author(s):  
Angela Lee ◽  
Weimin Mao ◽  
Mark S. Warren ◽  
Anita Mistry ◽  
Kazuki Hoshino ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Antibiotic Resistance ◽  
Efflux Pump ◽  
External Medium ◽  
Efflux Pumps ◽  
Single Component ◽  
Structural Types ◽  
First Case ◽  
Multiplicative Effects ◽  
Simultaneous Expression

ABSTRACT The effects of simultaneous expression of several efflux pumps on antibiotic resistance were investigated in Escherichia coliand Pseudomonas aeruginosa. Several combinations of efflux pumps have been studied: (i) simultaneous expression of a single-component efflux pump, which exports antibiotics into the periplasm, in combination with a multicomponent efflux pump that accomplishes efflux directly into the external medium; (ii) simultaneous expression of two single-component pumps; and (iii) simultaneous expression of two multicomponent pumps. It was found that when efflux pumps of different structural types were combined in the same cell (the first case), the observed antibiotic resistance was much higher than that conferred by each of the pumps expressed singly. Simultaneous expression of pairs of single-component or multicomponent efflux pumps (the second and third cases) did not produce strong increases in antibiotic resistance.

scholarly journals Alkylaminoquinolines inhibit the bacterial antibiotic efflux pump in multidrug-resistant clinical isolates

2003 ◽  
Vol 376 (3) ◽  
pp. 801-805 ◽  
Author(s):  
Monique MALLÉA ◽  
Abdallah MAHAMOUD ◽  
Jacqueline CHEVALIER ◽  
Sandrine ALIBERT-FRANCO ◽  
Pierre BROUANT ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Efflux Pump ◽  
Efflux Pumps ◽  
Multidrug Resistant ◽  
Clinical Isolates ◽  
Microbial Pathogens ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
High Level ◽  
Antibiotic Efflux

Over the last decade, MDR (multidrug resistance) has increased worldwide in microbial pathogens by efflux mechanisms, leading to treatment failures in human infections. Several Gram-negative bacteria efflux pumps have been described. These proteinaceous channels are capable of expelling structurally different drugs across the envelope and conferring antibiotic resistance in various bacterial pathogens. Combating antibiotic resistance is an urgency and the blocking of efflux pumps is an attractive response to the emergence of MDR phenotypes in infectious bacteria. In the present study, various alkylaminoquinolines were tested as potential inhibitors of drug transporters. We showed that alkylaminoquinolines are capable of restoring susceptibilities to structurally unrelated antibiotics in clinical isolates of MDR Gram-negative bacteria. Antibiotic efflux studies indicated that 7-nitro-8-methyl-4-[2´-(piperidino)ethyl]aminoquinoline acts as an inhibitor of the AcrAB–TolC efflux pump and restores a high level of intracellular drug concentration. Inhibitory activity of this alkylaminoquinoline is observed on clinical isolates showing different resistance phenotypes.

scholarly journals Emergence of a Potent Multidrug Efflux Pump Variant That Enhances Campylobacter Resistance to Multiple Antibiotics

mBio ◽  
2016 ◽  
Vol 7 (5) ◽  
Author(s):  
Hong Yao ◽  
Zhangqi Shen ◽  
Yang Wang ◽  
Fengru Deng ◽  
Dejun Liu ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Multidrug Resistance ◽  
Efflux Pump ◽  
Efflux Pumps ◽  
The United States ◽  
Drug Binding ◽  
Resistance To Antibiotics ◽  
Multiple Drugs ◽  
Antibiotic Efflux ◽  
Multiple Antibiotics

ABSTRACT Bacterial antibiotic efflux pumps are key players in antibiotic resistance. Although their role in conferring multidrug resistance is well documented, the emergence of “super” efflux pump variants that enhance bacterial resistance to multiple drugs has not been reported. Here, we describe the emergence of a resistance-enhancing variant (named RE-CmeABC) of the predominant efflux pump CmeABC in Campylobacter , a major zoonotic pathogen whose resistance to antibiotics is considered a serious antibiotic resistance threat in the United States. Compared to the previously characterized CmeABC transporters, RE-CmeABC is much more potent in conferring Campylobacter resistance to antibiotics, which was shown by increased MICs and reduced intracellular accumulation of antibiotics. Structural modeling suggests that sequence variations in the drug-binding pocket of CmeB possibly contribute to the enhanced efflux function. Additionally, RE-CmeABC expands the mutant selection window of ciprofloxacin, enhances the emergence of antibiotic-resistant mutants, and confers exceedingly high-level resistance to fluoroquinolones, an important class of antibiotics for clinical therapy of campylobacteriosis. Furthermore, RE-CmeABC is horizontally transferable, shifts antibiotic MIC distribution among clinical isolates, and is increasingly prevalent in Campylobacter jejuni isolates, suggesting that it confers a fitness advantage under antimicrobial selection. These findings reveal a new mechanism for enhanced multidrug resistance and an effective strategy utilized by bacteria for adaptation to selection from multiple antibiotics. IMPORTANCE Bacterial antibiotic efflux pumps are ubiquitously present in bacterial organisms and protect bacteria from the antibacterial effects of antimicrobials and other toxic compounds by extruding them out of cells. Thus, these efflux transporters represent an important mechanism for antibiotic resistance. In this study, we discovered the emergence and increasing prevalence of a unique efflux pump variant that is much more powerful in the efflux of antibiotics and confers multidrug resistance in Campylobacter , which is a major foodborne pathogen transmitted to humans via the food chain. Unlike other specific resistance determinants that only allow bacteria to resist a particular antimicrobial, the acquisition of a functionally enhanced efflux pump will empower bacteria with simultaneous resistance to multiple classes of antibiotics. These findings reveal a previously undescribed mechanism for enhanced multidrug resistance and open a new direction for us to understand how bacteria adapt to antibiotic treatment.

scholarly journals An Update on Plant-Derived Compounds as Potential Inhibitors of the Bacterial Efflux Pumps: With Reference to Staphylococcus aureus and Escherichia coli

2018 ◽  
Author(s):  
Saurav Das ◽  
Santosh Kumar ◽  
Pabitra Bhagowati ◽  
Ashish Kumar Singh
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Efflux Pump ◽  
Efflux Pumps ◽  
Health Concern ◽  
Multi Drug Resistance ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
Potential Inhibitors

Bacterial antibiotic resistance has become a major global health concern. One of the main reasons for the development of multi-drug resistance properties in bacteria is due to the bacterial efflux pump systems. They are important transport proteins, mainly involved in the removal of toxic substrates like antibiotics from inner cell environment. These pumps are responsible for the intrinsic ability of bacteria to get resistant to the antibiotic. Various types of efflux pumps are present in the Gram-positive and Gram-negative bacteria. Plant-derived products like Capsaicin, Olympicin A, and Indirubicin were found to be inhibitors of an efflux pump in Staphylococcus aureus similarly Ursolic acid derivatives; Daidzein and Lanatoside C were plant-derived inhibitors of an efflux pump in Escherichia coli. In this review detail information have been provided about efflux pump inhibitors that have been found to be effective in the Gram-positive bacteria and Gram-negative bacteria. The aim of this review is to focus on the role of plant-derived compounds as effective efflux pumps inhibitors with reference to mainly Staphylococcus aureus and Escherichia coli.

scholarly journals Antibiotic Resistance of Escherichia Coli Isolated from Lake Nainital, Uttarakhand State, India

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Neha Giri ◽  
Anchal Lodhi ◽  
Devendra Singh Bisht ◽  
Suvarna Bhoj ◽  
Deepak Kumar Arya
Keyword(s):  
Escherichia Coli ◽  
Antibiotic Resistance ◽  
Multiple Drug Resistance ◽  
Health Concern ◽  
Penicillin G ◽  
Resistant Bacteria ◽  
Sample Collection ◽  
E Coli ◽  
Mar Index ◽  
Collection Sites

Researchers have encountered new challenges with the discovery of multiple drug resistance in microbes. Currently, multidrug resistant bacteria are considered a major public health concern and an emerging global epidemic. Presence of Escherichia coli in water is used as a faecal pollution measure. In this study E. coli isolates were collected from 20 sample collection sites at Lake Nainital. 20 E. coli isolates, 1 from each sample collection sites, were examined for their antibiotic response patterns against a panel of widely used 15 antibiotics. The result of this study showed 100% resistance to Penicillin G followed by Erythromycin (80%). All isolates (100%) were found susceptible for Gentamycin. The susceptibilities for Chloramphenicol and Co-trimoxazaole were found next to Gentamycin as 90 and 85% respectively. Multiple antibiotic resistance (MAR) index was also determined. 0.73 MAR index was observed as highest in 1 isolate. 13 out of 20 isolates had more than 0.2 MAR indices. The result reveals the origin of E. coli isolates from an area of high antibiotics use.

scholarly journals A Preliminary Study: Antibiotic Resistance Patterns of Escherichia coli and Enterococcus Species from Wildlife Species Subjected to Supplementary Feeding on Various South African Farms

Animals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 396 ◽  
Author(s):  
Michaela Sannettha van den Honert ◽  
Pieter Andries Gouws ◽  
Louwrens Christiaan Hoffman
Keyword(s):  
Escherichia Coli ◽  
Antibiotic Resistance ◽  
Supplementary Feeding ◽  
Health Concern ◽  
Diffusion Method ◽  
Disk Diffusion Method ◽  
E Coli ◽  
Wildlife Species ◽  
Human Contact ◽  
Resistance Patterns

Studies have shown that antibiotic resistance among wild animals is becoming a public health concern, owing to increased contact and co-habitation with domestic animals that, in turn, results in increased human contact, indirectly and directly. This type of farming practice intensifies the likelihood of antibiotic resistant traits in microorganisms transferring between ecosystems which are linked via various transfer vectors, such as rivers and birds. This study aimed to determine whether the practice of wildlife supplementary feeding could have an influence on the antibiotic resistance of the bacteria harboured by the supplementary fed wildlife, and thus play a potential role in the dissemination of antibiotic resistance throughout nature. Escherichia coli and Enterococcus were isolated from the faeces of various wildlife species from seven different farms across South Africa. The Kirby-Bauer disk diffusion method was used according to the Clinical and Laboratory Standards Institute 2018 guidelines. The E. coli (F: 57%; N = 75% susceptible) and Enterococcus (F: 67%; N = 78% susceptible) isolates from the supplementary fed (F) wildlife were in general, found to be more frequently resistant to the selection of antibiotics than from those which were not supplementary fed (N), particularly towards tetracycline (E. coli F: 56%; N: 71%/Enterococcus F: 53%; N: 89% susceptible), ampicillin (F: 82%; N = 95% susceptible) and sulphafurazole (F: 68%; N = 98% susceptible). Interestingly, high resistance towards streptomycin was observed in the bacteria from both the supplementary fed (7% susceptible) and non-supplementary fed (6% susceptible) wildlife isolates. No resistance was found towards chloramphenicol and ceftazidime.

scholarly journals The Evolutionary Conservation of Escherichia coli Drug Efflux Pumps Supports Physiological Functions

2020 ◽  
Vol 202 (22) ◽  
Author(s):  
Tanisha Teelucksingh ◽  
Laura K. Thompson ◽  
Georgina Cox
Keyword(s):  
Escherichia Coli ◽  
Efflux Pump ◽  
Efflux Pumps ◽  
Evolutionary Conservation ◽  
Drug Efflux ◽  
Physiological Functions ◽  
Content Type ◽  
Bacterial Physiology ◽  
E Coli ◽  
Drug Efflux Pumps

ABSTRACT Bacteria harness an impressive repertoire of resistance mechanisms to evade the inhibitory action of antibiotics. One such mechanism involves efflux pump-mediated extrusion of drugs from the bacterial cell, which significantly contributes to multidrug resistance. Intriguingly, most drug efflux pumps are chromosomally encoded components of the intrinsic antibiotic resistome. In addition, in terms of xenobiotic detoxification, bacterial efflux systems often exhibit significant levels of functional redundancy. Efflux pumps are also considered to be highly conserved; however, the extent of conservation in many bacterial species has not been reported and the majority of genes that encode efflux pumps appear to be dispensable for growth. These observations, in combination with an increasing body of experimental evidence, imply alternative roles in bacterial physiology. Indeed, the ability of efflux pumps to facilitate antibiotic resistance could be a fortuitous by-product of ancient physiological functions. Using Escherichia coli as a model organism, we here evaluated the evolutionary conservation of drug efflux pumps and we provide phylogenetic analysis of the major efflux families. We show the E. coli drug efflux system has remained relatively stable and the majority (∼80%) of pumps are encoded in the core genome. This analysis further supports the importance of drug efflux pumps in E. coli physiology. In this review, we also provide an update on the roles of drug efflux pumps in the detoxification of endogenously synthesized substrates and pH homeostasis. Overall, gaining insight into drug efflux pump conservation, common evolutionary ancestors, and physiological functions could enable strategies to combat these intrinsic and ancient elements.

Antibiotic Resistance Profile of Commensal Escherichia coli Isolated from Broiler Chickens in Qatar

2017 ◽  
Vol 81 (2) ◽  
pp. 302-307 ◽  
Author(s):  
Nahla O. Eltai ◽  
Elmoubasher A. Abdfarag ◽  
Hamad Al-Romaihi ◽  
Eman Wehedy ◽  
Mahmoud H. Mahmoud ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Antibiotic Resistance ◽  
Broiler Chickens ◽  
Susceptibility Testing ◽  
Multidrug Resistant ◽  
Test Method ◽  
Health Concern ◽  
E Coli ◽  
Extended Spectrum ◽  
Stewardship Program

ABSTRACT Antibiotic resistance (AR) is a growing public health concern worldwide, and it is a top health challenge in the 21st century. AR among Enterobacteriaceae is rapidly increasing, especially in third-generation cephalosporins and carbapenems. Further, strains carrying mobilized colistin resistance (mcr) genes 1 and 2 have been isolated from humans, food-producing animals, and the environment. The uncontrolled use of antibiotics in food-producing animals is a major factor in the generation and spread of AR. No studies have been done to evaluate AR in the veterinary sector of Qatar. This study aimed at establishing primary baseline data for the prevalence of AR among food-producing animals in Qatar. Fecal samples (172) were obtained from two broiler farms and one live bird market in Qatar, and 90 commensal Escherichia coli bacteria were isolated and subjected to susceptibility testing against 16 clinically relevant antibiotics by using the E-test method. The results found that 81 (90%) of 90 isolates were resistant to at least one antibiotic, 14 (15.5%) of 90 isolates were colistin resistant, 2 (2.2%) of 90 isolates were extended-spectrum β-lactamase producers, and 2 (2.2%) of 90 isolates were multidrug resistant to four antibiotic classes. Extended-spectrum β-lactamase–producing E. coli and colistin-resistant isolates were confirmed by using double-disc susceptibility testing and PCR, respectively. Such a high prevalence of antibiotic-resistant E. coli could be the result of a long application of antibiotic treatment, and it is an indicator of the antibiotic load in food-producing animals in Qatar. Pathogens carrying AR can be easily transmitted to humans through consumption of undercooked food or noncompliance with hygiene practices, mandating prompt development and implementation of a stewardship program to control and monitor the use of antibiotics in the community and agriculture.

scholarly journals Antibiotic Resistance Patterns of Diverse Escherichia coli Phylogenetic Groups Isolated from the Al-Hillah River in Babylon Province, Iraq

2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Mourouge Saadi Alwash ◽  
Hawraa Mohammed Al-Rafyai
Keyword(s):  
Escherichia Coli ◽  
Antibiotic Resistance ◽  
Anthropogenic Activities ◽  
Health Concern ◽  
Resistant Bacteria ◽  
Anthropogenic Pressures ◽  
Phylogenetic Groups ◽  
E Coli ◽  
Resistance Patterns ◽  
Antibiotic Resistance Patterns

Surface water contamination remains a major worldwide public health concern and may contribute to the dissemination of antibiotic-resistant bacteria. The Al-Hillah River in the city of Babylon Province, Iraq, diverts flows from the Euphrates River. Because of its importance in irrigation and population density, it faces several forced and unforced changes due to anthropogenic activities. To evaluate water quality, water samples were collected from three sites with different anthropogenic pressures along the Al-Hillah River. These samples were subjected to bacteriological analyses, i.e., total coliforms, Escherichia coli, and faecal enterococci. The phylogenetic groups of the E. coli isolates (n = 61) were typed by rapid PCR-based analyses. Representatives of each isolate were tested phenotypically for resistance to six classes of antibiotics and characterized according to their phylogenetic groups. The results demonstrated the highest resistance levels were to β-lactam antibiotics, followed by fosfomycin and aminoglycosides. Escherichia coli isolates belonging to phylogenetic groups A and B2 were the most common and were characterized by a higher prevalence of antibiotic resistance. This study is important for understanding the current conditions of the Al-Hillah River, as the data reveal a high prevalence of multiresistance among E. coli isolates circulating at the three sampling sites.

Sign in / Sign up

Export Citation Format

Share Document