RND efflux pump mediated antibiotic resistance in Gram-negative bacteria Escherichia coli and Pseudomonas aeruginosa: a major issue worldwide

One of the major families of membrane proteins found in prokaryote genome corresponds to the transporters. Among them, the resistance-nodulation-cell division (RND) transporters are highly studied, as being responsible for one of the most problematic mechanisms used by bacteria to resist to antibiotics, i.e., the active efflux of drugs. In Gram-negative bacteria, these proteins are inserted in the inner membrane and form a tripartite assembly with an outer membrane factor and a periplasmic linker in order to cross the two membranes to expulse molecules outside of the cell. A lot of information has been collected to understand the functional mechanism of these pumps, especially with AcrAB-TolC from Escherichia coli, but one missing piece from all the suggested models is the role of peptidoglycan in the assembly. Here, by pull-down experiments with purified peptidoglycans, we precise the MexAB-OprM interaction with the peptidoglycan from Escherichia coli and Pseudomonas aeruginosa, highlighting a role of the peptidoglycan in stabilizing the MexA-OprM complex and also differences between the two Gram-negative bacteria peptidoglycans.

Download Full-text

Emergence of Colistin Resistant Gram-Negative Bacteria in a Tertiary Care Rural Hospital in 2019

KYAMC Journal ◽

10.3329/kyamcj.v11i2.48421 ◽

2020 ◽

Vol 11 (2) ◽

pp. 87-90

Author(s):

Abdullah Akhtar Ahmed ◽

Nusrat Akhtar Juyee ◽

SM Ali Hasan

Keyword(s):

Escherichia Coli ◽

Pseudomonas Aeruginosa ◽

Tertiary Care ◽

Salmonella Typhi ◽

Rural Hospital ◽

Gram Negative Bacteria ◽

Bacterial Isolates ◽

Colistin Resistance ◽

Sensitivity Testing ◽

Gram Negative

Background: Colistin-resistant Gram-negative bacteria is a rapidly emerging global threatgenerated a sense of public alarm. Objective: To combat this challenge a study was designedto evaluate the fast spreading infections by colistin-resistant pathogens in the tertiary care rural hospital of Bangladesh. Materials and Methods: To study isolation ofpathogenic gram-negative bacilli,clinical sample (n-640) of hospitalized patients of Khwaja Yunus Ali Medical College Hospital in Enayetpur, Bangladesh during the 1st quarter of the year 2019 were used. The bacterial isolates were screened for meropenem and colistin-resistance. Results: A total of 156 bacterial isolates were studied which included Escherichia coli (n-112), Klebsiella pneumoniae (n-14), Pseudomonas aeruginosa (n-27), and Salmonella typhi (n-3). Antibiotic sensitivity testing showed that 32/156(20%) and 119/156 (76%) isolates were resistant to meropenem and colistin, respectively. whereas 50/156 (32%) isolates were resistant to both antibiotics. Escherichia coli, K. pneumoniae, pseudomonas aeruginosa, and Salmonella typhi isolates respectivelywere 112/156 (72%), 14/156 (9%). 27/156 (17%), and 3/156 (2%). Conclusion: Colistin is typically used as salvage therapy, or last-line treatment, for MDR gramnegative infections.But there is worrisome therapeutic scenario in our study finding of colistin resistance is 76% in Gram-negative bacteria of the clinical isolates. The restricted and rational use of colistin drug is the need of hour. KYAMC Journal Vol. 11, No.-2, July 2020, Page 87-90

Download Full-text

National Surveillance of Antimicrobial Susceptibility of Bacteremic Gram-Negative Bacteria with Emphasis on Community-Acquired Resistant Isolates: Report from the 2019 Surveillance of Multicenter Antimicrobial Resistance in Taiwan (SMART)

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.01089-20 ◽

2020 ◽

Vol 64 (10) ◽

Author(s):

Po-Yu Liu ◽

Yu-Lin Lee ◽

Min-Chi Lu ◽

Pei-Lan Shao ◽

Po-Liang Lu ◽

...

Keyword(s):

Escherichia Coli ◽

Pseudomonas Aeruginosa ◽

Antimicrobial Resistance ◽

Klebsiella Pneumoniae ◽

Gram Negative Bacteria ◽

National Surveillance ◽

Gram Negative ◽

Content Type ◽

E Coli ◽

Carbapenem Resistant

ABSTRACT A multicenter collection of bacteremic isolates of Escherichia coli (n = 423), Klebsiella pneumoniae (n = 372), Pseudomonas aeruginosa (n = 300), and Acinetobacter baumannii complex (n = 199) was analyzed for susceptibility. Xpert Carba-R assay and sequencing for mcr genes were performed for carbapenem- or colistin-resistant isolates. Nineteen (67.8%) carbapenem-resistant K. pneumoniae (n = 28) and one (20%) carbapenem-resistant E. coli (n = 5) isolate harbored blaKPC (n = 17), blaOXA-48 (n = 2), and blaVIM (n = 1) genes.

Download Full-text

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

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.42.1.65 ◽

1998 ◽

Vol 42 (1) ◽

pp. 65-71 ◽

Cited By ~ 119

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.

Download Full-text

Susceptibility of Gram-negative bacteria to the synergistic bactericidal action of serum and polymyxin B nonapeptide

Canadian Journal of Microbiology ◽

10.1139/m86-013 ◽

1986 ◽

Vol 32 (1) ◽

pp. 66-69 ◽

Cited By ~ 7

Author(s):

Petri Viljanen ◽

Helena Käyhty ◽

Martti Vaara ◽

Timo Vaara

Keyword(s):

Escherichia Coli ◽

Pseudomonas Aeruginosa ◽

Enterobacter Cloacae ◽

Polymyxin B ◽

Gram Negative Bacteria ◽

Bactericidal Action ◽

Gram Negative ◽

Degree Of Sensitization ◽

Normal Human ◽

Klebsiella Spp

Polymyxin B nonapeptide was able to sensitize Escherichia coli strains and strains of Salmonella typhimurium, Klebsiella spp., Enterobacter cloacae, Pseudomonas aeruginosa, and Haemophilus influenzae to the bactericidal action of fresh normal human serum. The degree of sensitization varied significantly within the strains. Strains of Proteus mirabilis, Neisseria gonorrhoeae, and N. meningitidis remained resistant.

Download Full-text

Gram Negative Bacteria (GNB) Isolated From Used Home-made and Surgical Nose/Face Mask by Local Residents of Akungba Akoko, Ondo State, a Threat to Life and False Sense of Protection against SARS-CoV-2 (COVID-19)

Asian Journal of Advanced Research and Reports ◽

10.9734/ajarr/2021/v15i1030428 ◽

2021 ◽

pp. 1-17

Author(s):

Oludare Temitope Osuntokun

Keyword(s):

Escherichia Coli ◽

Pseudomonas Aeruginosa ◽

Proteus Mirabilis ◽

Antimicrobial Agents ◽

Face Mask ◽

Gram Negative Bacteria ◽

Haemophilus Influenza ◽

Gram Negative ◽

False Sense ◽

Zones Of Inhibition

Nose/Face masks are physical barriers to respiratory droplets that may enter through the nose and mouth to cause infections in the respiratory tract. The study was determined and assess the presence of Gram-negative bacteria in used home-made and surgical nose mask by residents of Akungba-Akoko Ondo State and to determine the antimicrobial susceptibility and resistant profile of the isolated bacteria to eight (8) different antimicrobial agents. The antimicrobial analysis were performed using standard microbiological and biochemical methods. Antimicrobial Susceptibility test of all identified isolates to antimicrobial agents were determined using the standard Kirby-Bauer disk diffusion method. The Gram-negative bacteria that were detected from the used home-made and surgical nose mask in this study include: Haemophilus influenza, Proteus mirabilis, Escherichia coli, Pseudomonas aeruginosa and Klebsiella pneumonia. During this study, all the Gram-negative bacteria isolates were resistant to Ciproflox in both used home-made and surgical nose mask. All isolates were also resistant to Ampicilin, Augmentin, Septrin and Streptomycin. In this study, Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa were isolated organism from used home-made nose mask, it was observed that Escherichia coli were resistant to Augmentin, Tarivid, Ciproflox, Gentamycin, and Reflaxine, and Pseudomonas aeruginosa were resistant to Tarivid, Ciproflox, and Nalidixic acid between 20 mm and 24 mm zones of inhibition respectively. Haemophilus influenza, Pseudomonas aeruginosa, Escherichia coli and Proteus mirabilis were isolated organism from used surgical nose mask. It was observed that all isolated organisms from the used surgical nose/face mask were resistant to Augmentin and Gentamycin between 20 and 24 mm zones of inhibition respectively. Klebsiella pneumoniae were isolated from both used home-made and surgical nose/face mask and were found to be resistant to Streptomycin, Septrin, Ampicilin, and Gentamicin between 20 to 22 mm zones of inhibition respectively. Proteus mirabilis were isolated from used surgical nose/face mask, they were found to be resistant to Ciproflox at 21mm zones of inhibition. Haemophilus influenza were resistant to Ampicilin, Septrin, Streptomycin, and Augmentin at 23 mm zones of inhibition. Isolates from used both home-made and surgical nose/face mask were subjected to modified and synergized antibiotics, it was observed that the isolates from both used home-made and surgical nose mask were resistant to all modified and synergized antibiotics between 20 and 25 mm zones of inhibition respectively. The result of this study validates the potency of Gram negative bacteria isolated from used both home-made and surgical nose/face mask and the degree of invasion and evasiveness, thereby causing various degrees of infections and a false sense of protection against SARS-CoV-2 (COVID-19). Finding from this research recommends a stringent measures were needed to be implemented, to halt and combat this revenging situation especially in the new era of mutating SARS-CoV-2 Virus not only in Nigeria, worldwide at large.

Download Full-text

Green Synthesis of Silver Nanoparticles Using Novel Launaea Procumbens Leaves Extract and Screening Its Antibacterial Activity

10.21203/rs.3.rs-1049725/v1 ◽

2021 ◽

Author(s):

Sanjay Ratan Kumavat ◽

SATYENDRA MISHRA

Keyword(s):

Escherichia Coli ◽

Staphylococcus Aureus ◽

Pseudomonas Aeruginosa ◽

Silver Nanoparticles ◽

Green Synthesis ◽

Gram Negative Bacteria ◽

Zone Of Inhibition ◽

Gram Negative ◽

Green Synthesized Silver Nanoparticles ◽

Launaea Procumbens

Abstract Plants are emerging as a cost-effective and ecofriendly method for green synthesis of nanoparticles. The plant extract Launaea procumbens was used as a reduction agent in the green synthesis of silver nanoparticles. UV-Visible spectroscopy, HR-TEM, SAED, FE-SEM, EDAX, DLS, and FT-IR were used to study the green synthesized silver nanoparticles. UV-Vis spectroscopy of a prepared silver solution revealed maximum absorption at 435 nm. The synthesized silver nanoparticles were found to be spherical in shape with a size in the range of 24.28 to 31.54 nm. DLS analysis was used to determine the size of the green synthesized silver nanoparticles, which showed outstanding antibacterial action against Gram-positive bacteria Bacillus subtilis and Staphylococcus aureus, as well as Gram-negative bacteria Escherichia coli and Pseudomonas aeruginosa. Gram-positive Bacillus subtilis had a maximum zone of inhibition of 20 mm, Staphylococcus aureus had a zone of inhibition of 19 mm, and Gram-negative bacteria Escherichia coli and Pseudomonas aeruginosa had zones of inhibition of 13 mm.

Download Full-text

QUANTITATIVE ESTIMATION AND ANTIMICROBIAL POTENTIAL OF ETHANOL EXTRACT OF DURIO ZIBETHINUS MURR. LEAVES

Asian Journal of Pharmaceutical and Clinical Research ◽

10.22159/ajpcr.2017.v10i9.19767 ◽

2017 ◽

Vol 10 (9) ◽

pp. 251

Author(s):

Sridevi Chigurupati ◽

Jahidul Islam Mohammad ◽

Shantini Vijayabalan ◽

Narmatha Devi Vaipuri ◽

Kesavanarayanan Krishnan Selvarajan ◽

...

Keyword(s):

Escherichia Coli ◽

Pseudomonas Aeruginosa ◽

Quantitative Estimation ◽

Antibacterial Properties ◽

Diffusion Method ◽

Gram Negative Bacteria ◽

Human Pathogens ◽

Gram Negative ◽

Antimicrobial Potential ◽

Durio Zibethinus

Objectives: Current research is aimed to investigate the natural antimicrobial potential of Durio zibethinus murr. ethanol leaves extract (DZL).Methods: DZL was subjected to the preliminary phytochemical screening along with quantitative analysis of phenols and flavonoids. Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) were recorded. The agar well diffusion method was used to measure the antibacterial activity against gram positive and gram negative bacteria. The microorganisms used for the study were the ATCC strains of Bacillus subtilis, Enterococcus faecalis, Staphylococcus aureus, Streptococcus pyogenes, Neisseria gonorrhoeae, Pseudomonas aeruginosa and Escherichia coli.Results: DZL exhibited the highest MIC of 0.1mg/mL and MBC of 0.25 mg/mL against gram negative bacteria, Pseudomonas aeruginosa and Escherichia coli. At MIC of 0.1mg/mL, DZL displayed significant zone of inhibition against Pseudomonas aeruginosa and Escherichia coli compared to gentamycin.Conclusion: This research has shown that DZL has natural antibacterial properties against gram negative human pathogens.

Download Full-text

Core oligosaccharide portion of lipopolysaccharide plays important roles on multiple antibiotic resistance in Escherichia coli

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00341-21 ◽

2021 ◽

Author(s):

Jianli Wang ◽

Wenjian Ma ◽

Yu Fang ◽

Hao Liang ◽

Huiting Yang ◽

...

Keyword(s):

Escherichia Coli ◽

Antibiotic Resistance ◽

Cell Envelope ◽

Gene Clusters ◽

Gram Negative Bacteria ◽

Multiple Antibiotic Resistance ◽

Core Oligosaccharide ◽

Gram Negative ◽

The Core ◽

K 12

Gram-negative bacteria are intrinsically resistant to antibiotics due to the presence of the cell envelope, but mechanisms are still not fully understood. In this study, a series of mutants that lack one or more major components associated with the cell envelope were constructed from Escherichia coli K-12 W3110. WJW02 can only synthesize Kdo 2 -lipid A which lacks the core oligosaccharide portion of lipopolysaccharide. WJW04, WJW07 and WJW08 were constructed from WJW02 by deleting the gene clusters relevant to the biosynthesis of exopolysaccharide, flagella and fimbria, respectively. WJW09, WJW010 and WJW011 cells cannot synthesize exopolysaccharide, flagella and fimbria, respectively. Comparing to the wild type W3110, mutants WJW02, WJW04, WJW07 and WJW08 cells showed decreased resistance to more than 10 different antibacterial drugs, but not the mutants WJW09, WJW010 and WJW011. This indicates that the core oligosaccharide portion of lipopolysaccharide plays important roles on multiple antibiotic resistance in E. coli and the 1 st heptose in core oligosaccharide portion is critical. Furthermore, the removal of the core oligosaccharide of LPS leads to influences on cell wall morphology, cell phenotypes, porins, efflux systems, and the respond behaviors to antibiotic stimulation. The results demonstrated the important role of lipopolysaccharide on the antibiotic resistance of Gram-negative bacteria.

Download Full-text

An Essential Membrane Protein Modulates the Proteolysis of LpxC to Control Lipopolysaccharide Synthesis in Escherichia coli

mBio ◽

10.1128/mbio.00939-20 ◽

2020 ◽

Vol 11 (3) ◽

Cited By ~ 15

Author(s):

Elayne M. Fivenson ◽

Thomas G. Bernhardt

Keyword(s):

Escherichia Coli ◽

Antibiotic Resistance ◽

Outer Membrane ◽

Unknown Function ◽

Barrier Function ◽

Major Determinant ◽

Gram Negative Bacteria ◽

Gram Negative ◽

Content Type ◽

Essential Protein

ABSTRACT Gram-negative bacteria are surrounded by a complex cell envelope that includes two membranes. The outer membrane prevents many drugs from entering these cells and is thus a major determinant of their intrinsic antibiotic resistance. This barrier function is imparted by the asymmetric architecture of the membrane with lipopolysaccharide (LPS) in the outer leaflet and phospholipids in the inner leaflet. The LPS and phospholipid synthesis pathways share an intermediate. Proper membrane biogenesis therefore requires that the flux through each pathway be balanced. In Escherichia coli, a major control point in establishing this balance is the committed step of LPS synthesis mediated by LpxC. Levels of this enzyme are controlled through its degradation by the inner membrane protease FtsH and its presumed adapter protein LapB (YciM). How turnover of LpxC is controlled has remained unclear for many years. Here, we demonstrate that the essential protein of unknown function YejM (PbgA) participates in this regulatory pathway. Suppressors of YejM essentiality were identified in lpxC and lapB, and LpxC overproduction was shown to be sufficient to allow survival of ΔyejM mutants. Furthermore, the stability of LpxC was shown to be reduced in cells lacking YejM, and genetic and physical interactions between LapB and YejM were detected. Taken together, our results are consistent with a model in which YejM directly modulates LpxC turnover by FtsH-LapB to regulate LPS synthesis and maintain membrane homeostasis. IMPORTANCE The outer membrane is a major determinant of the intrinsic antibiotic resistance of Gram-negative bacteria. It is composed of both lipopolysaccharide (LPS) and phospholipid, and the synthesis of these lipid species must be balanced for the membrane to maintain its barrier function in blocking drug entry. In this study, we identified an essential protein of unknown function as a key new factor in modulating LPS synthesis in the model bacterium Escherichia coli. Our results provide novel insight into how this organism and most likely other Gram-negative bacteria maintain membrane homeostasis and their intrinsic resistance to antibiotics.

Download Full-text