&lt;p&gt;Survey on Genetic Diversity, Biofilm Formation, and Detection of Colistin Resistance Genes in Clinical Isolates of &lt;em&gt;Acinetobacter baumannii&lt;/em&gt;&lt;/p&gt;

Khoshnood, Saeed; Savari, Mohammad; Montazeri, Effat Abbasi; Sheikh, Ahmad Farajzadeh

doi:10.2147/idr.s253440

Cited by 30 publications

(30 citation statements)

References 50 publications

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“…24,33 Up to date, there is still no regular pattern in the relationship between biofilm formation ability and bacterial antimicrobial resistance, and the conclusions between different researches were even contradictory. 24,[33][34][35][36] In our research, the non-MDR strains could produce stronger biofilm compared with MDR strains, indicating that the antimicrobial resistance and biofilm formation ability were negatively correlated in A. baumannii. Rodriguez-Bano et al have illustrated that biofilm-forming A. baumannii isolates were more sensitive to ciprofloxacin and imipenem, 37 suggesting that these strains were not as dependent on antimicrobial resistance as non-biofilm-forming isolates for survival, which was consistent with our result.…”

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confidence: 57%

Phenotypic and Genotypic Characteristics of Biofilm Formation in Clinical Isolates of Acinetobacter baumannii

Li¹,

Ding²,

Liu³

et al. 2021

IDR

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Background: Acinetobacter baumannii is an important pathogen in clinical infections, and biofilm formation is an effective way for A. baumannii to survive under external pressures. In this study, the aims were to examine the antimicrobial resistance, biofilm formation, and biofilm-specific resistance in clinical isolates of A. baumannii. Materials and Methods: A total of 104 clinical A. baumannii isolates were collected from a large teaching hospital in Southwest China. The antibiotics susceptibilities were tested, and biofilm-forming ability was evaluated by crystal violet staining by confocal laser scanning microscopy (CLSM). Minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), minimum biofilm inhibitory concentration (MBIC), and minimum biofilm eradication concentration (MBEC) of ciprofloxacin, meropenem, and ceftazidime were tested on selected strains by broth microdilution method. Biofilm-associated genes were detected by polymerase chain reaction (PCR), and expression of genes at planktonic stage and biofilm stage were analyzed by real-time reverse transcription PCR (RT-PCR). Results: Multidrug-resistant (MDR) isolates accounted for 65.4%, but no strain was resistant to tigecycline and polymyxin B. Moreover, non-MDR strains tended to form stronger biofilms than MDR strains, and a negative correlation between biofilm-forming ability and resistance profiles to each of tested antimicrobials were observed. The MBECs and MBICs of ciprofloxacin, ceftazidime, and meropenem were evidently increased compared with MICs and MBCs among all tested strains. Additionally, the biofilm formation ability of the csuDpositive strains was stronger than that of the csuD-negative strains. The strains in MDR group had higher carrying rate of csuA and csuD genes than non-MDR group, while non-MDR strains possessed more ompA gene than MDR group. Finally, abaI gene was significantly up-regulated after biofilm formation. Conclusion:These results revealed valuable data for the negative correlation between antimicrobial resistance and biofilm formation, as well as phenotypic and genotypic characteristics of biofilm formation in A. baumannii.

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confidence: 57%

Phenotypic and Genotypic Characteristics of Biofilm Formation in Clinical Isolates of Acinetobacter baumannii

Li¹,

Ding²,

Liu³

et al. 2021

IDR

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“…The biofilm formation ability of the A. baumannii isolates on 96-well polystyrene microtiter plates was assessed using the crystal violet staining, as formerly described [ 27 ]. The results were classified into the four following categories [ 28 ]: non-biofilm producer, weak biofilm producer, medium biofilm producer, and strong biofilm producer.…”

Section: Methodsmentioning

confidence: 99%

Bloodstream infections caused by ST2 Acinetobacter baumannii: risk factors, antibiotic regimens, and virulence over 6 years period in China

Zeng

et al. 2021

Antimicrob Resist Infect Control

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Background Bloodstream infection (BSI) caused by multidrug-resistant Acinetobacter baumannii (MDR-AB) has been increasingly observed among hospitalized patients. The following study analyzed the epidemiology and microbiological characteristics of MDR-AB, as well as the clinical features, antimicrobial treatments, and outcomes in patients over a six years period in China. Methods This retrospective study was conducted in a large tertiary hospital in China between January 2013 and December 2018. The clinical and microbiological data of all consecutive hospitalized patients with MDR-AB induced bloodstream infection were included and analyzed. Results A total of 108 BSI episodes were analyzed. All MDR isolates belonged to ST2, a sequence type that has spread all over the world. Overall, ST2 strains showed strong biofilm formation ability, high serum resistance, and high pathogenicity. As for the clinical characteristics of the patient, 30-day mortality was 69.4% (75/108). The three main risk factors included mechanical ventilation, intensive care unit (ICU) stay, and thrombocytopenia; three protective factors included a change of antimicrobial regimen within 48 h after positive blood culture, use of the antibacterial agent combination, and more inpatient days. The most effective antibacterial regimen was the combination of cefoperazone/sulbactam and tigecycline. Conclusions BSI caused by ST2 A.baumannii represents a difficult challenge for physicians, considering the high mortality associated with this infection. The combination of cefoperazone/sulbactam and tigecycline may be an effective treatment option.

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“…Extent of resistance exhibited by A. baumannii against different classes of antibiotics results in failure of the various treatment strategies in hospital set-ups. In addition, high frequency of biofilm formation mediated by various biofilm associated genes often correlates with the Drug resistance among the clinical strains of A. baumannii [13]. Amongst various biofilm related genes adhesion based genetic determinants is highly attributed for the bacteria to colonize and to establish an infection in host…”

Section: Correlation Of Fimh With Multidrug Resistancementioning

confidence: 99%

Frequency of Adhesive Virulence Factor fimH among the Clinical Isolates of Acinetobacter baumannii in India

Padmaja

Girija

Priyadharsini

2020

JPRI

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The objective of the study was to detect the presence of fimH gene among the drug resistanst strains of Acinetobacter baumannii. fimH gene was found to be associated with a catch bond mechanism which led to better evolution of biofilm formation. Since there are not many studies done with this gene it would be a timely investigation and this study mainly aims in molecular characterization of fimH gene among clinical isolates of A. baumannii. Semi quantitative bio adherent assay was done by the multidrug resistant strains of A. baumannii to find the formation of biofilm. The DNA was extracted with the help of kit and PCR was performed for amplification. Pearson correlation analysis was done to find the existing correlation between the fimH gene and MDR strains of A. baumannii with significant p-value of (<0.05). From the screened 73 genomes of MDR A. baumannii 6.8% showed positive amplicons for the fimH gene which were related to biofilm and porin formation (Fig. 1). Correlation of its existence was high in beta lactamase (100%), cephems (100%), folate (100%) resistant strains, followed by aminoglycosides (80%), carbapenems (60%) and fluoroquinolones (60%) and efflux pumps (20%). In Spite of various measures undertaken to prevent the disease, the prevalence of the pathogen is multiplying. The current study recorded the presence of fimHgene (6.8%) among the clinical isolates of A.baumannii. This gene can be used as a target to develop new drugs and vaccines to combat the menace of A.baumannii infection.

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<p>Survey on Genetic Diversity, Biofilm Formation, and Detection of Colistin Resistance Genes in Clinical Isolates of <em>Acinetobacter baumannii</em></p>

Cited by 30 publications

References 50 publications

Phenotypic and Genotypic Characteristics of Biofilm Formation in Clinical Isolates of Acinetobacter baumannii

Phenotypic and Genotypic Characteristics of Biofilm Formation in Clinical Isolates of Acinetobacter baumannii

Bloodstream infections caused by ST2 Acinetobacter baumannii: risk factors, antibiotic regimens, and virulence over 6 years period in China

Frequency of Adhesive Virulence Factor fimH among the Clinical Isolates of Acinetobacter baumannii in India

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