scholarly journals Phonotypic Investigation of Biofilm Formation and Determination of Presence of bap and blaOXA-51 Genes in Acinetobacter baumannii From Clinical Specimens in Tehran

2020 ◽  
Vol 14 (6) ◽  
pp. 566-583
Author(s):  
Vahid Rouhi ◽  
Roya Safarkar ◽  
Sanaz Habibi ◽  
◽  
◽  
...  
Keyword(s):  
Acinetobacter Baumannii ◽  
Biofilm Formation ◽  
Clinical Specimens

scholarly journals Detection of Genes Involved in Biofilm Formation in MDR and XDR Acinetobacter baumannii Isolated from Human Clinical Specimens in Isfahan, Iran

2019 ◽  
Vol In Press (In Press) ◽  
Author(s):  
Ahad Mahmoudi Monfared ◽  
Aliakbar Rezaei ◽  
Farkhondeh Poursina ◽  
Jamshid Faghri
Keyword(s):  
Acinetobacter Baumannii ◽  
Biofilm Formation ◽  
Clinical Specimens

scholarly journals Determination of the prevalence of blaoxa-like gene and ISAba1 elements among extensiveــdrug resistant (XDR) Acinetobacter boumannii isolates

Bionatura ◽  
2021 ◽  
Vol 6 (4) ◽  
pp. 2284-2291
Author(s):  
Salah Mohsin ◽  
Wasan Abdul-Elah Bakir ◽  
Majeed Arsheed
Keyword(s):  
Acinetobacter Baumannii ◽  
Drug Resistant ◽  
Disc Diffusion ◽  
Chain Reaction ◽  
Clinical Specimens ◽  
Diffusion Technique ◽  
Microbiological Techniques ◽  
Polymerase Chain ◽  
State Of Affairs

The capacity of Multiـdrug resistant (MDR) Acinetobacter baumannii to survive in any state of affairs concerning the gaining of various gene types of virulence and antimicrobial agent resistance are the main anxiety in the hospital’s environments. So, it is very crucial to determine the prevalence of insertion sequences in A. baumannii. In the hospitals. Detecting the blaoxa-51 gene through the polymerase chain reaction (PCR) was performed to confirm Acinetobacter baumannii and the search for ISAba1 element. Between October 2020 and February 2021, 540 distinct clinical specimens were gathered from five hospitals in Baghdad. Thirty-eight A. baumannii isolates were obtained from various clinical specimens. The isolates were initially identified phenotypically using standard microbiological techniques and by the Vitek2 compact automated machine. Isolates of A. baumannii were identified genotypically by amplification of the blaoxa-51-like gene. Antimicrobials are studied by Kirby-Bauer (disc diffusion) technique on Muller-Hinton agar as specified by the recent clinical and laboratory standard institute (CLSI) guidelines (2020). The actual results of the current study indicated that from total isolated (38) A.baumannii isolates, 23 isolates (61%) were resistant to meropenem and 25 isolates (66%) were resistant to imipenem. The blaoxa-51 gene was identified in all strains examined, ISAba1 was also present in all A. baumannii isolates. ISAba1 has a high predominance between drug-resistant A. baumannii. Identifying these parameters can assist in the control of infection and decreasing the microorganism’s prevalence rate.

scholarly journals Molecular detection of virulence factors and biofilm formation in Pseudomonas aeruginosa obtained from different clinical specimens in Bandar Abbas

2019 ◽  
Author(s):  
Nima Bahador ◽  
Saeed Shoja ◽  
Foroogh Faridi ◽  
Banafsheh Dozandeh-Mobarrez ◽  
Fatemeh Izadpanah Qeshmi ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Virulence Factors ◽  
Antimicrobial Susceptibility ◽  
Biofilm Formation ◽  
Opportunistic Pathogen ◽  
Clinical Specimens ◽  
Biofilm Production ◽  
Bandar Abbas ◽  
Susceptibility Patterns

Background and Objectives: Pseudomonas aeruginosa is a ubiquitous opportunistic pathogen. The presence of several virulence factors such as exotoxin and exoenzyme genes and biofilm may contribute to its pathogenicity. The purpose of this study was to investigate the presence of toxA, exoU and exoS, the determination of biofilm production and antimicrobial susceptibility patterns among clinical isolates of P. aeruginosa. Materials and Methods: In this study, 75 isolates of P. aeruginosa were recovered from various clinical specimens. Antimi- crobial susceptibility pattern of isolates were identified. Virulence genes toxA, exoU and exoS were determined using PCR. The ability of biofilm production was assessed. Results: Antimicrobial susceptibility test showed that 12 strains were resistant to more than 8 antibiotics (17.14%). The most effective antibiotic was colistin as 98.6% of isolates were sensitive. The frequencies of exoU and exoS genes were detected as 36.6% and 55.7%, respectively. In addition, 98.6% of the isolates were biofilm producers. Exotoxin A was detected in sixty-eight isolates (95.7%). Conclusion: The findings of this study showed that, the presence of P. aeruginosa exotoxin and exoenzyme genes, particu- larly, the exoU gene is the most common virulence factors in the bacterial isolates from urine samples. Biofilm is a serious challenge in the treatment of P. aeruginosa infection.

scholarly journals Prevalence Determination of Virulence Related and Biofilm Formation Genes in Acinetobacter baumannii Isolates from Clinical Respiratory Samples in Imam Khomeini Hospital, Tehran, Iran in 2018

2021 ◽  
Vol 15 (3) ◽  
pp. 266-280
Author(s):  
Haniyeh Mozafari ◽  
◽  
Shiva Mirkalantari ◽  
Behrooz Sadeghi Kalani ◽  
Nour Amirmozafari ◽  
...  
Keyword(s):  
Acinetobacter Baumannii ◽  
Biofilm Formation

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.

scholarly journals Lon Protease Has Multifaceted Biological Functions inAcinetobacter baumannii

2018 ◽  
Vol 201 (2) ◽  
Author(s):  
Carly Ching ◽  
Brendan Yang ◽  
Chineme Onwubueke ◽  
David Lazinski ◽  
Andrew Camilli ◽  
...  
Keyword(s):  
Acinetobacter Baumannii ◽  
Biofilm Formation ◽  
Developmental Process ◽  
Cell Envelope ◽  
Opportunistic Pathogen ◽  
Lon Protease ◽  
Content Type ◽  
Hospital Acquired Infections ◽  
Biofilm Development ◽  
Hospital Acquired

ABSTRACTAcinetobacter baumanniiis a Gram-negative opportunistic pathogen that is known to survive harsh environmental conditions and is a leading cause of hospital-acquired infections. Specifically, multicellular communities (known as biofilms) ofA. baumanniican withstand desiccation and survive on hospital surfaces and equipment. Biofilms are bacteria embedded in a self-produced extracellular matrix composed of proteins, sugars, and/or DNA. Bacteria in a biofilm are protected from environmental stresses, including antibiotics, which provides the bacteria with selective advantage for survival. Although some gene products are known to play roles in this developmental process inA. baumannii, mechanisms and signaling remain mostly unknown. Here, we find that Lon protease inA. baumanniiaffects biofilm development and has other important physiological roles, including motility and the cell envelope. Lon proteases are found in all domains of life, participating in regulatory processes and maintaining cellular homeostasis. These data reveal the importance of Lon protease in influencing keyA. baumanniiprocesses to survive stress and to maintain viability.IMPORTANCEAcinetobacter baumanniiis an opportunistic pathogen and is a leading cause of hospital-acquired infections.A. baumanniiis difficult to eradicate and to manage, because this bacterium is known to robustly survive desiccation and to quickly gain antibiotic resistance. We sought to investigate biofilm formation inA. baumannii, since much remains unknown about biofilm formation in this bacterium. Biofilms, which are multicellular communities of bacteria, are surface attached and difficult to eliminate from hospital equipment and implanted devices. Our research identifies multifaceted physiological roles for the conserved bacterial protease Lon inA. baumannii. These roles include biofilm formation, motility, and viability. This work broadly affects and expands understanding of the biology ofA. baumannii, which will permit us to find effective ways to eliminate the bacterium.

scholarly journals EMERGENCE AND ANTIBIOTIC SENSITIVITY PATTERN OF ACINETOBACTER BAUMANNII IN HOSPITAL FACILITY

2017 ◽  
Vol 10 (3) ◽  
pp. 77
Author(s):  
Anania Arjuna ◽  
Dinobandhu Nandi
Keyword(s):  
Acinetobacter Baumannii ◽  
Nosocomial Infections ◽  
Antibiotic Sensitivity ◽  
Hospital Environment ◽  
Sensitivity Testing ◽  
Hospital Acquired Infection ◽  
Clinical Specimens ◽  
Sensitivity Pattern ◽  
Tract Infections ◽  
Hospital Acquired

ABSTRACTObjective: Nosocomial infections or Hospital acquired infection (HAI) are one of the major threats to hospitalized patients as well as for the hospitalassociated personnel. In last few years there is a gross change in causative agents, new organisms have come out with great threat to hospitals as theypossess antibiotic resistance property e.g. production of biofilm, production of enzymes such as β- lactamases. Among many organisms, Acinetobacterbaumannii has emerged as a potent nosocomial pathogen. Our objective of this study was to find the burden of Acinetobacter baumannii infectionswhich are associated as nosocomial infections and to determine the drug of choice for an effective treatment.Methods: Clinical specimens were collected from patients of different unit of the hospital by maintaining universal precautions and standardmicrobiological protocols. All the respective specimens were cultured in respective culture medium i.e. MacConkey agar, blood agar, chocolate agar,cysteine lactose electrolyte deficient (CLED) agar and, fluid thioglycolate (TG) medium at 37˚C for 24-48 hours. After incubation of 24-48 hours cultureplates were examined for bacterial growth and identification and antibiotic sensitivity test was made by Vitek2 compact.Result: The study was conducted at the department of microbiology from January 2016 to April 2016. A total of 2582 specimens were collected andprocessed for identification and sensitivity testing. Specimens of all age group (2 days- 93 years) and both sexes were processed for identificationof A. baumannii and antibiotic sensitivity testing. A total of 119 isolates (4.60%) of A. baumannii were obtained from 2582 clinical specimens. Themost common infection A. baumannii was found as lower respiratory tract infection (89.07%) followed by abscess (6.72%), septicaemia (2.52%),urinary tract infections (0.84%), and soft tissue infections (0.84%). The maximum sensitivity of A. baumannii isolates were seen to Colistin (CL) (119,100%), followed by Tigecycline (TGC) (63, 52.94%) and Minocycline (MIN) (27, 22.69%). The maximum resistant was observed for Imipenem (IMI),Aztreonam (AZT) and Ticarcillin- clavulanic acid (TIC) (119, 100%).Conclusion: The Gram- negative coccobacillus, Acinetobacter baumannii poses a formidable threat to patients. It has emerged as a superbug inhospital environment particularly in ICU units. The chances of A. baumannii infections increase in the presence of iatrogenic factors like inadequatelong- term antibiotic therapy and new interventions in a medical facility. To control the burden of Acinetobacter infections new therapies suchas combine therapy must be obtained and followed with proper dose as recommend by physicians; along with awareness of the importance ofthis infection should be implicated. Proper sanitation, good housekeeping, sterilization of equipment, hand hygiene, water purification, isolationprocedures and maintaining of the hospital environment, use of infection control practices are some of the measures to control the transmission ofAcinetobacter spp. among hospital personnel.Keywords: Acinetobacter baumannii, Biofilm, β-lactamases, Hospital acquired infection.

scholarly journals Growth Retardation, Reduced Invasiveness, and Impaired Colistin-Mediated Cell Death Associated with Colistin Resistance Development in Acinetobacter baumannii

2013 ◽  
Vol 58 (2) ◽  
pp. 828-832 ◽  
Author(s):  
Spyros Pournaras ◽  
Aggeliki Poulou ◽  
Konstantina Dafopoulou ◽  
Yassine Nait Chabane ◽  
Ioulia Kristo ◽  
...  
Keyword(s):  
Cell Death ◽  
Acinetobacter Baumannii ◽  
Biofilm Formation ◽  
Bloodstream Infections ◽  
Single Amino Acid ◽  
Colistin Resistance ◽  
Resistance Development ◽  
Content Type ◽  
Alkyl Hydroperoxide ◽  
Severe Soft Tissue

ABSTRACTTwo colistin-susceptible/colistin-resistant (Cols/Colr) pairs ofAcinetobacter baumanniistrains assigned to international clone 2, which is prevalent worldwide, were sequentially recovered from two patients after prolonged colistin administration. Compared with the respective Colsisolates (Ab248 and Ab299, both having a colistin MIC of 0.5 μg/ml), both Colrisolates (Ab249 and Ab347, with colistin MICs of 128 and 32 μg/ml, respectively) significantly overexpressedpmrCABgenes, had single-amino-acid shifts in the PmrB protein, and exhibited significantly slower growth. The Colrisolate Ab347, tested by proteomic analysis in comparison with its Colscounterpart Ab299, underexpressed the proteins CsuA/B and C from thecsuoperon (which is necessary for biofilm formation). This isolate also underexpressed aconitase B and different enzymes involved in the oxidative stress response (KatE catalase, superoxide dismutase, and alkyl hydroperoxide reductase), suggesting a reduced response to reactive oxygen species (ROS) and, consequently, impaired colistin-mediated cell death through hydroxyl radical production. Colsisolates that were indistinguishable by macrorestriction analysis from Ab299 caused six sequential bloodstream infections, and isolates indistinguishable from Ab248 caused severe soft tissue infection, while Colrisolates indistinguishable from Ab347 and Ab249 were mainly colonizers. In particular, a Colsisolate identical to Ab299 was still invading the bloodstream 90 days after the colonization of this patient by Colrisolates. These observations indicate considerably lower invasiveness ofA. baumanniiclinical isolates following the development of colistin resistance.

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