scholarly journals The success of particular Acinetobacter baumannii clones: accumulating resistance and virulence inside a sugary shield

2020 ◽  
Author(s):  
Liliana Silva ◽  
Filipa Grosso ◽  
Carla Rodrigues ◽  
Magdalena Ksiezarek ◽  
Helena Ramos ◽  
...  
Keyword(s):  
Acinetobacter Baumannii ◽  
Mammalian Cells ◽  
Virulence Genes ◽  
Attenuated Total Reflection ◽  
Snp Analysis ◽  
Sugar Composition ◽  
Carbapenem Resistant ◽  
Antimicrobial Resistance Profile ◽  
Capsule Locus ◽  
Pseudaminic Acid

Abstract Background In Portugal, carbapenem-resistant Acinetobacter baumannii (CRAB) has been associated with ST98, ST103 and ST208 (Oxford Scheme, Oxf) and a clone has usually been associated with a particular period of time. These clonal shifts were primarily explained by an increased antimicrobial resistance profile. Here we explore genomic and biochemical differences among these and more recent clones, which could further explain the diversity and evolution of this species. Methods A total of 116 CRAB isolates (2010–15), together with representatives of a previously described CRAB collection (4 isolates, 2001–06) were characterized by attenuated total reflection Fourier transform infrared spectroscopy (FTIR-ATR) and MLST. Representatives of different FTIR-ATR/MLST clusters were selected for WGS (n = 13), which allowed the in silico extraction of resistance and virulence genes, capsule locus and SNP analysis. Results A. baumannii clonal shifts of OXA-58-producing ST103Oxf (2001–04), OXA-40-producing ST98Oxf (2002–06), OXA-23-producing ST208Oxf (2006–10) and OXA-23-producing ST218Oxf (2010–15) were accompanied by an increase in AMR genes and virulence factors. FTIR-ATR clustering was congruent with sugar composition predicted from the capsular locus: a fucosamine cluster comprising ST98Oxf, ST103Oxf and a single ST218Oxf isolate; a pseudaminic acid cluster of ST208Oxf and ST1557Oxf isolates; and legionaminic acid, resembling the sialic acid from mammalian cells, in a cluster comprising ST218Oxf isolates. The whole-genome phylogenetic tree was congruent with MLST, with isolates presenting 5–28 938 SNPs. ST208Oxf and ST218Oxf presented ∼1900 SNPs while ST103Oxf and ST1557Oxf showed a greater number of SNPs (∼28 000). Conclusions Clonal shifts of CRAB were promoted, in our country, by consecutive virulence and AMR gene pool enlargement, together with features increasing pathogen–host adaptation. Worldwide dominance of ST218Oxf is supported by the combination of high AMR and virulence levels.

scholarly journals Whole-Genome Sequencing for Investigating a Health Care-Associated Outbreak of Carbapenem-Resistant Acinetobacter baumannii

Diagnostics ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 201
Author(s):  
Sang Mee Hwang ◽  
Hee Won Cho ◽  
Tae Yeul Kim ◽  
Jeong Su Park ◽  
Jongtak Jung ◽  
...  
Keyword(s):  
Whole Genome Sequencing ◽  
Acinetobacter Baumannii ◽  
Genome Sequencing ◽  
Snp Analysis ◽  
Whole Genome ◽  
Phylogenetic Tree Analysis ◽  
Web Based ◽  
Hospital Outbreak ◽  
Carbapenem Resistant ◽  
Bioinformatics Tools

Carbapenem-resistant Acinetobacter baumannii (CRAB) outbreaks in hospital settings challenge the treatment of patients and infection control. Understanding the relatedness of clinical isolates is important in distinguishing outbreak isolates from sporadic cases. This study investigated 11 CRAB isolates from a hospital outbreak by whole-genome sequencing (WGS), utilizing various bioinformatics tools for outbreak analysis. The results of multilocus sequence typing (MLST), single nucleotide polymorphism (SNP) analysis, and phylogenetic tree analysis by WGS through web-based tools were compared, and repetitive element polymerase chain reaction (rep-PCR) typing was performed. Through the WGS of 11 A. baumannii isolates, three clonal lineages were identified from the outbreak. The coexistence of blaOXA-23, blaOXA-66, blaADC-25, and armA with additional aminoglycoside-inactivating enzymes, predicted to confer multidrug resistance, was identified in all isolates. The MLST Oxford scheme identified three types (ST191, ST369, and ST451), and, through whole-genome MLST and whole-genome SNP analyses, different clones were found to exist within the MLST types. wgSNP showed the highest discriminatory power with the lowest similarities among the isolates. Using the various bioinformatics tools for WGS, CRAB outbreak analysis was applicable and identified three discrete clusters differentiating the separate epidemiologic relationships among the isolates.

scholarly journals First Description of Colistin and Tigecycline-Resistant Acinetobacter baumannii Producing KPC-3 Carbapenemase in Portugal

Antibiotics ◽  
2018 ◽  
Vol 7 (4) ◽  
pp. 96 ◽  
Author(s):  
Cátia Caneiras ◽  
Filipa Calisto ◽  
Gabriela Jorge da Silva ◽  
Luis Lito ◽  
José Melo-Cristino ◽  
...  
Keyword(s):  
Case Report ◽  
High Risk ◽  
Acinetobacter Baumannii ◽  
University Hospital ◽  
Virulence Determinants ◽  
Molecular Screening ◽  
Pcr Screening ◽  
Carbapenem Resistant ◽  
Antimicrobial Resistance Profile

Herein, we describe a case report of carbapenem-resistant Acinetobacter baumannii and Klebsiella pneumoniae isolates that were identified from the same patient at a Tertiary University Hospital Centre in Portugal. Antimicrobial susceptibility and the molecular characterization of resistance and virulence determinants were performed. PCR screening identified the presence of the resistance genes blaKPC-3, blaTEM-1 and blaSHV-1 in both isolates. The KPC-3 K. pneumoniae isolate belonged to the ST-14 high risk clone and accumulated an uncommon resistance and virulence profile additional to a horizontal dissemination capacity. In conclusion, the molecular screening led to the first identification of the A. baumannii KPC-3 producer in Portugal with a full antimicrobial resistance profile including tigecycline and colistin.

Efficient Delivery of Antisense Oligonucleotides by an Amphipathic Cell-Penetrating Peptide in Acinetobacter baumannii

2019 ◽  
Vol 16 (8) ◽  
pp. 728-736 ◽  
Author(s):  
Zhou Chen ◽  
Dan Nie ◽  
Yue Hu ◽  
Mingkai Li ◽  
Zheng Hou ◽  
...  
Keyword(s):  
Acinetobacter Baumannii ◽  
Antisense Oligonucleotides ◽  
Mammalian Cells ◽  
Acyl Carrier Protein ◽  
High Specificity ◽  
Independent Manner ◽  
Amphipathic Peptide ◽  
Carbapenem Resistant ◽  
Efficient Delivery ◽  
Novel Strategy

Background: Carbapenem-resistant Acinetobacter baumannii (A. baumannii) was on the top of the list of the most threatening bacteria published by the WHO in 2017. Antisense oligonucleotides (ASOs) based therapy is a promising strategy for combating Multi-Drug Resistant (MDR) bacteria because of its high specificity, easy design and lower induction of resistance, but poor cellular uptake by bacteria has restricted the further utilization of this therapy. Methods: Here, we used CADY, a secondary amphipathic peptide of 20 residues that could successfully carry siRNA into mammalian cells, to prepare CADY/ASOs nanoparticles (CADY-NPs) targeting acpP (encoding acyl carrier protein), and evaluated the uptake features, the inhibitory effects of CADY-NPs on gene expression and the growth of MDR-A. baumannii. Results: We found that CADY-NPs could be quickly internalized by drug-sensitive and MDR-A. baumannii in an energy independent manner, which could be restrained by chlorpromazine (an inhibitor of clathrin mediated endocytosis) significantly. In addition, CADY-NPs targeting acpP concentrationdependently retarded the growth of MDR-A. baumannii, which was associated with the decreased expression of targeted genes in A. baumannii. Conclusion: In conclusion, our research is the first to demonstrate that CADY can deliver ASOs into bacteria and provide a novel strategy for the treatment of MDR-A. baumannii.

Molecular characterization of carbapenem-resistant Acinetobacter baumannii using WGS revealed missed transmission events in Germany from 2012–15

2019 ◽  
Vol 74 (12) ◽  
pp. 3473-3480 ◽  
Author(s):  
Tatjana Eigenbrod ◽  
Sandra Reuter ◽  
Andrea Gross ◽  
Kaan Kocer ◽  
Frank Günther ◽  
...  
Keyword(s):  
Acinetobacter Baumannii ◽  
Snp Analysis ◽  
Prevention Measures ◽  
Retrospective Assessment ◽  
Clonal Type ◽  
Carbapenem Resistant ◽  
Containment Measures ◽  
High Discriminatory Power ◽  
Spatio Temporal ◽  
Therapeutic Problem

Abstract Background Infection and colonization with multi-resistant Acinetobacter baumannii causes therapeutic and economic problems in the nosocomial setting. Due to the sensitivity issue of screening schemes for A. baumannii, it is difficult to implement adequate transmission prevention measures. The high discriminatory power of WGS for transmission-chain analysis provides us with the necessary tool to study and identify transmission events. We retrospectively sequenced and analysed 39 A. baumannii isolates from 2012–15 to search for possible missed transmission events. Methods Molecular typing by WGS was performed for non-repetitive (n=39) carbapenem-resistant A. baumannii. Retrospective assessment of patient records was performed to investigate and confirm possible transmission events. Results Between July 2012 and September 2015, A. baumannii was isolated from 268 patients, of which 16% (42/268) were carbapenem resistant. Thirty-nine of these isolates were recoverable and sequenced. Fifteen percent (6/39) of these were resistant to all antibiotics tested. Most isolates belong to the circulating IC2 clonal type. SNP analysis revealed four potential outbreak clusters. Two of these clusters showed high concordance with the local spatio-temporal epidemiology, suggesting that transmission events were very likely. Conclusions Our data suggest that there were two independent transmission events, which would have been missed by conventional MLST owing to high clonality. The routine implementation of WGS can optimize surveillance and initiation of suitable containment measures. In addition, emerging resistance to salvage therapy is a major therapeutic problem and should be monitored closely.

Community-acquired in name only: A cluster of carbapenem-resistant Acinetobacter baumannii in a burn intensive care unit and beyond

2020 ◽  
Vol 41 (5) ◽  
pp. 531-538 ◽  
Author(s):  
Erica S. Shenoy ◽  
Virginia M. Pierce ◽  
Mohamad R. A. Sater ◽  
Febriana K. Pangestu ◽  
Ian C. Herriott ◽  
...  
Keyword(s):  
Acinetobacter Baumannii ◽  
Tertiary Care ◽  
Index Patient ◽  
Environmental Sampling ◽  
Snp Analysis ◽  
Environmental Isolates ◽  
Carbapenem Resistant ◽  
Single Cluster ◽  
Clinical Cases

AbstractObjective:To describe an investigation into 5 clinical cases of carbapenem-resistant Acinetobacter baumannii (CRAB).Design:Epidemiological investigation supplemented by whole-genome sequencing (WGS) of clinical and environmental isolates.Setting:A tertiary-care academic health center in Boston, Massachusetts.Patients or participants:Individuals identified with CRAB clinical infections.Methods:A detailed review of patient demographic and clinical data was conducted. Clinical isolates underwent phenotypic antimicrobial susceptibility testing and WGS. Infection control practices were evaluated, and CRAB isolates obtained through environmental sampling were assessed by WGS. Genomic relatedness was measured by single-nucleotide polymorphism (SNP) analysis.Results:Four clinical cases spanning 4 months were linked to a single index case; isolates differed by 1–7 SNPs and belonged to a single cluster. The index patient and 3 case patients were admitted to the same room prior to their development of CRAB infection, and 2 case patients were admitted to the same room within 48 hours of admission. A fourth case patient was admitted to a different unit. Environmental sampling identified highly contaminated areas, and WGS of 5 environmental isolates revealed that they were highly related to the clinical cluster.Conclusions:We report a cluster of highly resistant Acinetobacter baumannii that occurred in a burn ICU over 5 months and then spread to a separate ICU. Two case patients developed infections classified as community acquired under standard epidemiological definitions, but WGS revealed clonality, highlighting the risk of burn patients for early-onset nosocomial infections. An extensive investigation identified the role of environmental reservoirs.

Decreased carO gene expression and OXA-type carbapenemases among extensively drug-resistant Acinetobacter baumannii strains isolated from burn patients in Tehran, Iran

2020 ◽  
Author(s):  
Elham Abbasi ◽  
Hossein Goudarzi ◽  
Ali Hashemi ◽  
Alireza Salimi Chirani ◽  
Abdollah Ardebili ◽  
...  
Keyword(s):  
Gene Expression ◽  
Acinetobacter Baumannii ◽  
High Rate ◽  
Burn Patients ◽  
Drug Resistant ◽  
Disc Diffusion ◽  
Carbapenem Resistant ◽  
Extensively Drug Resistant ◽  
Sds Page ◽  
Extensively Drug Resistance

AbstractA major challenge in the treatment of infections has been the rise of extensively drug resistance (XDR) and multidrug resistance (MDR) in Acinetobacter baumannii. The goals of this study were to determine the pattern of antimicrobial susceptibility, blaOXA and carO genes among burn-isolated A. baumannii strains. In this study, 100 A. baumannii strains were isolated from burn patients and their susceptibilities to different antibiotics were determined using disc diffusion testing and broth microdilution. Presence of carO gene and OXA-type carbapenemase genes was tested by PCR and sequencing. SDS-PAGE was done to survey CarO porin and the expression level of carO gene was evaluated by Real-Time PCR. A high rate of resistance to meropenem (98%), imipenem (98%) and doripenem (98%) was detected. All tested A. baumannii strains were susceptible to colistin. The results indicated that 84.9% were XDR and 97.9% of strains were MDR. In addition, all strains bore blaOXA-51 like and blaOXA-23 like and carO genes. Nonetheless, blaOXA-58 like and blaOXA-24 like genes were harbored by 0 percent and 76 percent of strains, respectively. The relative expression levels of the carO gene ranged from 0.06 to 35.01 fold lower than that of carbapenem-susceptible A. baumannii ATCC19606 and SDS – PAGE analysis of the outer membrane protein showed that all 100 isolates produced CarO. The results of current study revealed prevalence of blaOXA genes and changes in carO gene expression in carbapenem resistant A.baumannii.

PREVALENCE OF CARBAPENEM-RESISTANT ACINETOBACTER BAUMANNII (CRAB) IN MEDICAL AND SURGICAL INTENSIVE CARE UNITS (ICUS) OF JPMC, KARACHI

2019 ◽  
Author(s):  
Rabia Arshad
Keyword(s):  
Intensive Care ◽  
Antimicrobial Resistance ◽  
Acinetobacter Baumannii ◽  
Intensive Care Units ◽  
Carbapenem Resistance ◽  
Chronic Obstructive ◽  
Surgical Intensive Care ◽  
Carbapenem Resistant ◽  
Number Of Patients ◽  
Increased Risk

Background: Antimicrobial resistance is one of the research priorities of health organizations due to increased risk of morbidity and mortality. Outbreaks of nosocomial infections caused by carbapenem-resistant Acinetobacter Baumannii (CRAB) strains are at rise worldwide. Antimicrobial resistance to carbapenems reduces clinical therapeutic choices and frequently led to treatment failure. The aim of our study was to determine the prevalence of carbapenem resistance in A. baumannii isolated from patients in intensive care units (ICUs). Methods: This cross-sectional study was carried out in the Department of Microbiology, Basic Medical Sciences Institute (BMSI), Jinnah Postgraduate Medical Centre (JPMC), Karachi, from December 2016 to November 2017. Total 63 non-repetitive A. baumannii were collected from the patients’ specimens, admitted to medical and surgical ICUs and wards of JPMC, Karachi. The bacterial isolates were processed according to standard microbiological procedures to observe for carbapenem resistance. SPSS 21 was used for data analysis. Results: Out of the 63 patients, 40 (63.5%) were male. The age of the patient ranged from 15-85 year, with average of 43 year. 34.9% patients had been hospitalized for 3 days. Chronic obstructive pulmonary disease was present in highest number with average of 58.7% for morbidity. Number of patients on mechanical ventilation was highest (65.1%). All isolates were susceptible to colistin. The resistance to ampicillin-sulbactam, ceftazidime, ciprofloxacin, amikacin, piperacillin- tazobactam and meropenem was 82.5%, 81%, 100%, 87.3%, 82.5% and 82% respectively. Out of 82% CRAB, 77% were obtained from ICUs. Conclusion: This study has revealed the high rate of carbapenem resistance in A. baumannii isolates in ICUs thus leaving behind limited therapeutic options.

scholarly journals 813. The Reduction of the acquisition rate of carbapenem resistant Acinetobacter baumannii after room privatization in the intensive care unit

2020 ◽  
Vol 7 (Supplement_1) ◽  
pp. S448-S449
Author(s):  
Jongtak Jung ◽  
Pyoeng Gyun Choe ◽  
Chang Kyung Kang ◽  
Kyung Ho Song ◽  
Wan Beom Park ◽  
...  
Keyword(s):  
Regression Model ◽  
Acinetobacter Baumannii ◽  
Cox Regression ◽  
Univariate Analysis ◽  
Intervention Group ◽  
Feeding Tube ◽  
Control Group ◽  
Cox Regression Model ◽  
Carbapenem Resistant ◽  
Hospital Acquired

Abstract Background Acinetobacter baumannii is one of the major pathogens of hospital-acquired infection recently and hospital outbreaks have been reported worldwide. On September 2017, New intensive care unit(ICU) with only single rooms, remodeling from old ICU with multibed bay rooms, was opened in an acute-care tertiary hospital in Seoul, Korea. We investigated the effect of room privatization in the ICU on the acquisition of carbapenem-resistant Acinetobacter baumannii(CRAB). Methods We retrospectively reviewed medical records of patients who admitted to the medical ICU in a tertiary care university-affiliated 1,800-bed hospital from 1 January 2015 to 1 January 2019. Patients admitted to the medical ICU before the remodeling of the ICU were designated as the control group, and those who admitted to the medical ICU after the remodeling were designated as the intervention group. Then we compared the acquisition rate of CRAB between the control and intervention groups. Patients colonized with CRAB or patients with CRAB identified in screening tests were excluded from the study population. The multivariable Cox regression model was performed using variables with p-values of less than 0.1 in the univariate analysis. Results A total of 1,105 cases admitted to the ICU during the study period were analyzed. CRAB was isolated from 110 cases in the control group(n=687), and 16 cases in the intervention group(n=418). In univariate analysis, room privatization, prior exposure to antibiotics (carbapenem, vancomycin, fluoroquinolone), mechanical ventilation, central venous catheter, tracheostomy, the presence of feeding tube(Levin tube or percutaneous gastrostomy) and the length of ICU stay were significant risk factors for the acquisition of CRAB (p< 0.05). In the multivariable Cox regression model, the presence of feeding tube(Hazard ratio(HR) 4.815, 95% Confidence interval(CI) 1.94-11.96, p=0.001) and room privatization(HR 0.024, 95% CI 0.127-0.396, p=0.000) were independent risk factors. Table 1. Univariate analysis of Carbapenem-resistant Acinetobacter baumannii Table 2. Multivariable Cox regression model of the acquisition of Carbapenem-resistant Acinetobacter baumannii Conclusion In the present study, room privatization of the ICU was correlated with the reduction of CRAB acquisition independently. Remodeling of the ICU to the single room would be an efficient strategy for preventing the spreading of multidrug-resistant organisms and hospital-acquired infection. Disclosures All Authors: No reported disclosures

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