scholarly journals The influence of biofilm formation and multidrug resistance on environmental survival of clinical and environmental isolates of Acinetobacter baumannii

2016 ◽  
Vol 44 (5) ◽  
pp. e65-e71 ◽  
Author(s):  
Christine Greene ◽  
Gayathri Vadlamudi ◽  
Duane Newton ◽  
Betsy Foxman ◽  
Chuanwu Xi
Keyword(s):  
Multidrug Resistance ◽  
Acinetobacter Baumannii ◽  
Biofilm Formation ◽  
Environmental Isolates ◽  
Environmental Survival

Multidrug Resistance Related to Biofilm Formation in Acinetobacter baumannii and Klebsiella pneumoniae Clinical Strains from Different Pulsotypes

2016 ◽  
Vol 72 (5) ◽  
pp. 617-627 ◽  
Author(s):  
Paola Amaral de Campos ◽  
Sabrina Royer ◽  
Deivid William da Fonseca Batistão ◽  
Bruna Fuga Araújo ◽  
Lícia Ludendorff Queiroz ◽  
...  
Keyword(s):  
Multidrug Resistance ◽  
Klebsiella Pneumoniae ◽  
Acinetobacter Baumannii ◽  
Biofilm Formation ◽  
Clinical Strains

scholarly journals Biofilm formation in clinical isolates of nosocomial Acinetobacter baumannii and its relationship with multidrug resistance

2016 ◽  
Vol 6 (6) ◽  
pp. 528-533 ◽  
Author(s):  
Ebrahim Babapour ◽  
Azam Haddadi ◽  
Reza Mirnejad ◽  
Seyed-Abdolhamid Angaji ◽  
Nour Amirmozafari
Keyword(s):  
Multidrug Resistance ◽  
Acinetobacter Baumannii ◽  
Biofilm Formation ◽  
Clinical Isolates

scholarly journals Phenotypic and Genotypic Investigation of Biofilm Formation in Clinical and Environmental Isolates of Acinetobacter baumannii

2018 ◽  
Vol 13 (4) ◽  
Author(s):  
Ehsan Ghasemi ◽  
Zohreh Ghalavand ◽  
Hossein Goudarzi ◽  
Farshid Yeganeh ◽  
Ali Hashemi ◽  
...  
Keyword(s):  
Acinetobacter Baumannii ◽  
Biofilm Formation ◽  
Environmental Isolates

scholarly journals TheAcinetobacter baumanniiTwo-Component System AdeRS Regulates Genes Required for Multidrug Efflux, Biofilm Formation, and Virulence in a Strain-Specific Manner

mBio ◽  
2016 ◽  
Vol 7 (2) ◽  
Author(s):  
Grace E. Richmond ◽  
Laura P. Evans ◽  
Michele J. Anderson ◽  
Matthew E. Wand ◽  
Laura C. Bonney ◽  
...  
Keyword(s):  
Multidrug Resistance ◽  
Acinetobacter Baumannii ◽  
Biofilm Formation ◽  
Galleria Mellonella ◽  
Efflux Pump ◽  
Ex Vivo ◽  
Natural Infection ◽  
Opportunistic Pathogen ◽  
Multidrug Resistant ◽  
Component System

ABSTRACTThe opportunistic pathogenAcinetobacter baumanniiis able to persist in the environment and is often multidrug resistant (MDR), causing difficulties in the treatment of infections. Here, we show that the two-component system AdeRS, which regulates the production of the AdeABC multidrug resistance efflux pump, is required for the formation of a protective biofilm in anex vivoporcine mucosal model, which mimics a natural infection of the human epithelium. Interestingly, deletion ofadeBimpacted only on the ability of strain AYE to form a biofilm on plastic and only on the virulence of strain Singapore 1 forGalleria mellonella. RNA-Seq revealed that loss of AdeRS or AdeB significantly altered the transcriptional landscape, resulting in the changed expression of many genes, notably those associated with antimicrobial resistance and virulence interactions. For example,A. baumanniilacking AdeRS displayed decreased expression ofadeABC,pilgenes,comgenes, and apgaC-like gene, whereas loss of AdeB resulted in increased expression ofpilandcomgenes and decreased expression of ferric acinetobactin transport system genes. These data define the scope of AdeRS-mediated regulation, show that changes in the production of AdeABC mediate important phenotypes controlled by AdeRS, and suggest that AdeABC is a viable target for antimicrobial drug and antibiofilm discovery.IMPORTANCEAcinetobacter baumanniiis a nosocomial pathogen and is an increasing problem in hospitals worldwide. This organism is often multidrug resistant, can persist in the environment, and forms a biofilm on environmental surfaces and wounds. Overproduction of efflux pumps can allow specific toxic compounds to be pumped out of the cell and can lead to multidrug resistance. This study demonstrates the role of theA. baumanniiefflux pump AdeB, and its regulator AdeRS, in multidrug resistance, epithelial cell killing, and biofilm formation. Deletion of the genes encoding these systems led to increased susceptibility to antibiotics, decreased biofilm formation on biotic and abiotic surfaces, and decreased virulence. Our data suggest that inhibition of AdeB could prevent biofilm formation or colonization in patients byA. baumanniiand provides a good target for drug discovery.

scholarly journals Interaction of Acinetobacter baumannii with Human Serum Albumin: Does the Host Determines the Outcome?

Antibiotics ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 833
Author(s):  
Camila Pimentel ◽  
Casin Le ◽  
Marisel R. Tuttobene ◽  
Tomas Subils ◽  
Krisztina M. Papp-Wallace ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Human Serum Albumin ◽  
Quorum Sensing ◽  
Serum Albumin ◽  
Human Serum ◽  
Acinetobacter Baumannii ◽  
Biofilm Formation ◽  
Model Systems ◽  
Expression Levels ◽  
Multiple Drugs

Acinetobacter baumannii has become a serious threat to human health due to its extreme antibiotic resistance, environmental persistence, and capacity to survive within the host. Two A. baumannii strains, A118 and AB5075, commonly used as model systems, and three carbapenem-resistant strains, which are becoming ever more dangerous due to the multiple drugs they can resist, were exposed to 3.5% human serum albumin (HSA) and human serum (HS) to evaluate their response with respect to antimicrobial resistance, biofilm formation, and quorum sensing, all features responsible for increasing survival and persistence in the environment and human body. Expression levels of antibiotic resistance genes were modified differently when examined in different strains. The cmlA gene was upregulated or downregulated in conditions of exposure to 3.5% HSA or HS depending on the strain. Expression levels of pbp1 and pbp3 tended to be increased by the presence of HSA and HS, but the effect was not seen in all strains. A. baumannii A118 growing in the presence of HS did not experience increased expression of these genes. Aminoglycoside-modifying enzymes were also expressed at higher or lower levels in the presence of HSA or HS. Still, the response was not uniform; in some cases, expression was enhanced, and in other cases, it was tapered. While A. baumannii AB5075 became more susceptible to rifampicin in the presence of 3.5% HSA or HS, strain A118 did not show any changes. Expression of arr2, a gene involved in resistance to rifampicin present in A. baumannii AMA16, was expressed at higher levels when HS was present in the culture medium. HSA and HS reduced biofilm formation and production of N-Acyl Homoserine Lactone, a compound intimately associated with quorum sensing. In conclusion, HSA, the main component of HS, stimulates a variety of adaptative responses in infecting A. baumannii strains.

scholarly journals Antibiofilm and antivirulence potential of silver nanoparticles against multidrug-resistant Acinetobacter baumannii

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Helal F. Hetta ◽  
Israa M. S. Al-Kadmy ◽  
Saba Saadoon Khazaal ◽  
Suhad Abbas ◽  
Ahmed Suhail ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Antibacterial Activity ◽  
Acinetobacter Baumannii ◽  
Biofilm Formation ◽  
Microtiter Plate ◽  
Diffusion Method ◽  
Resistance Pattern ◽  
Infection Model ◽  
The Impact

AbstractWe aimed to isolate Acinetobacter baumannii (A. baumannii) from wound infections, determine their resistance and virulence profile, and assess the impact of Silver nanoparticles (AgNPs) on the bacterial growth, virulence and biofilm-related gene expression. AgNPs were synthesized and characterized using TEM, XRD and FTIR spectroscopy. A. baumannii (n = 200) were isolated and identified. Resistance pattern was determined and virulence genes (afa/draBC, cnf1, cnf2, csgA, cvaC, fimH, fyuA, ibeA, iutA, kpsMT II, PAI, papC, PapG II, III, sfa/focDE and traT) were screened using PCR. Biofilm formation was evaluated using Microtiter plate method. Then, the antimicrobial activity of AgNPs was evaluated by the well-diffusion method, growth kinetics and MIC determination. Inhibition of biofilm formation and the ability to disperse biofilms in exposure to AgNPs were evaluated. The effect of AgNPs on the expression of virulence and biofilm-related genes (bap, OmpA, abaI, csuA/B, A1S_2091, A1S_1510, A1S_0690, A1S_0114) were estimated using QRT-PCR. In vitro infection model for analyzing the antibacterial activity of AgNPs was done using a co-culture infection model of A. baumannii with human fibroblast skin cell line HFF-1 or Vero cell lines. A. baumannii had high level of resistance to antibiotics. Most of the isolates harbored the fimH, afa/draBC, cnf1, csgA and cnf2, and the majority of A. baumannii produced strong biofilms. AgNPs inhibited the growth of A. baumannii efficiently with MIC ranging from 4 to 25 µg/ml. A. baumannii showed a reduced growth rate in the presence of AgNPs. The inhibitory activity and the anti-biofilm activity of AgNPs were more pronounced against the weak biofilm producers. Moreover, AgNPs decreased the expression of kpsMII , afa/draBC,bap, OmpA, and csuA/B genes. The in vitro infection model revealed a significant antibacterial activity of AgNPs against extracellular and intracellular A. baumannii. AgNPs highly interrupted bacterial multiplication and biofilm formation. AgNPs downregulated the transcription level of important virulence and biofilm-related genes. Our findings provide an additional step towards understanding the mechanisms by which sliver nanoparticles interfere with the microbial spread and persistence.

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