Molecular Detection of Class-D OXA Carbapenemase Genes in Biofilm and Non-Biofilm Forming Clinical Isolates of Acinetobacter baumannii

Azizi, Omid; Shakibaie, Mohammad Reza; Modaresi, Farzan; Shahcheraghi, Fereshteh

doi:10.5812/jjm.21042

Cited by 33 publications

(40 citation statements)

References 23 publications

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“…One loopful of each sample was streaked on cysteine electrolyte deficient (CLED) (Hi‐Media, Mumbai, India) and blood agar base (Merck) to which 5 mL of fresh sheep blood was added and incubated at 37 °C for 24 h. Well‐isolated colonies were then subjected to conventional diagnostic tests and confirmed to species level by API20 NE (BioMérieux, Marcy‐l'Etoile, France) diagnostic test as well as bla OXA51 ‐PCR. Biofilm quantification and the presence of AHL compound were also investigated as described previously . The individual colonies were inoculated into sterile True North TM Cryogenic Vials (TNC) containing 1 mL sterile tryptic soy broth (BioMérieux) mixed with 40% glycerol and preserved at −70 °C for further study.…”

Section: Methodsmentioning

confidence: 99%

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Effect of iron on expression of efflux pump (adeABC) and quorum sensing (luxI, luxR) genes in clinical isolates of Acinetobacter baumannii

Modaresi

Azizi

Shakibaie

et al. 2015

APMIS

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Resistance-nodulation-division efflux system (RND) adeABC contributes to intrinsic resistance to various drug classes in Acinetobacter baumannii. Similarly, quorum sensing (QS) plays an important role in the biofilm formation and pathogenicity of this bacterium. The aims of this study were to evaluate the influence of iron limitation on the expression of efflux pump (adeABC) genes and QS (luxI, luxR) system by relative quantitative real-time polymerase chain reaction (qRT-PCR). In addition, DNA sequence and phylogenetic relatedness of biofilm-associated protein (Bap) gene was also investigated. Sixty-five multidrug-resistant isolates of A. baumannii were recovered from ICU patients of three hospitals in Kerman, Iran. The isolates were highly resistant to at least 11 antibiotics (MIC ≥64 μg/mL); however, 87% and 89% were susceptible to colistin and tigecycline, respectively (MIC 0.05 μg/mL) (p ≤ 0.05). We detected the presence of RND efflux pump, QS, and bap genes with the frequencies of 92% (adeA), 61.5% (adeB), 84.6% (adeC), 80% (luxI), 61% (luxR), and 66% (bap), respectively. qRT-PCR analysis showed that in some isolates, expression of both adeABC and luxI/R was increased more than fourfold in the presence of low iron (20 μm), suggesting the additional regulatory role of iron on both efflux pump and QS system. Alignment and phylogenetic analysis on the strong biofilm forming isolates confirmed that the fragments amplified were indeed part of bap gene and deduced sequence was similar to A. baumannii K9B410.

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Section: Methodsmentioning

confidence: 99%

“…In many cases, acquiring plasmids and integrons from resistant bacteria were responsible for many outbreaks of infections in various hospitals . Multidrug‐resistant A. baumannii (MDR‐AB) strains are often susceptible only to carbapenems and colistin, though resistant to imipenem and colistin, are increasingly reported .…”

mentioning

confidence: 99%

Effect of iron on expression of efflux pump (adeABC) and quorum sensing (luxI, luxR) genes in clinical isolates of Acinetobacter baumannii

Modaresi

Azizi

Shakibaie

et al. 2015

APMIS

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“…Due to its intrinsic resistance to antimicrobial agents and harsh environments, it can survive and spread in hostile niches, such as hospitals. In enterococcal infections, biofilm plays an essential role by providing a context to enhance microbial survival in the host (32)(33)(34). Several studies were conducted to identify the virulence factors of enterococci and their possible association with biofilm formation, but this issue is not yet well understood.…”

Section: Discussionmentioning

confidence: 99%

Virulence Factor and Biofilm Formation in Clinical Enterococcal Isolates of the West of Iran

Azizi¹,

Banafshe²,

Kashef³

et al. 2017

Jundishapur J Microbiol

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Background: Enterococcus spp., a part of the normal flora of the human intestine, possess several virulence factors that can develop biofilms to endure harsh environments. Their ability to cause nosocomial infections makes them as critical opportunistic pathogens in hospital settings. Objectives: The current study aimed at determining the occurrence of 6 genes coding virulence factors and their ability to develop biofilms, and conducting phenotypical assessments of haemolysin and gelatinase in clinical enterococci isolated from the West of Iran. Methods: A total of 126 isolates were screened for harbouring the following genes: aggregation substance (asa1), cytolysin (cylABM), enterococcal surface protein (esp), and gelatinase (gelE). Isolates were tested for haemolysin and gelatinase expression phenotypically and for biofilm production quantitatively, using the microtiter method.Results: Of the 126 tested isolates, 95 (73%) were Enterococcus faecalis and 28 (21%) were E. faecium. The total frequency of virulence gene was cylA 92 (73%), cylB 85 (67%), cylM 57 (45%), asa1 26 (21%), gelE 64 (51%), and esp 66 (53%); while 98 (75%) of the isolates were able to form biofilm. A total of 74 (58%) and 46 (35%) isolates could secret haemolysin and gelatinase. Conclusions: There was a significant difference between the frequency of virulence gene in E. faecalis and E. faecium. Enterococcus faecium isolates lacked the gelE and asa1 genes and the frequency of cylABM genes were lower than that of E. faecalis isolates. Enterococcus faecalis isolates were relatively rich in virulence factors; no association was observed between biofilm formation and the presence of specific virulence genes.

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“…Genomic DNA was extracted from 90 isolates of P. aeruginosa and 90 isolates of A. baumannii by boiling method as described previously (20). Briefly, two well separated colonies of each isolate were dissolved in 200 µl of sterile D/W in 1.5 µl capacity Eppendorf tubes (Eppendorf, Germany) and placed in boiling water bath for 20 minutes.…”

Section: Genomic Dna Extractionmentioning

confidence: 99%

Prevalence of Class 1, 2, and 3 Integrons and Biofilm Formation in Pseudomonas aeruginosa and Acinetobacter baumannii among ICU and non-ICU Patients

Aryanezhad¹,

Shakibaie²,

Karmostaji³

et al. 2016

IEM

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Background:Infections caused by Pseudomonas aeruginosa or Acinetobacter baumannii are of greatest concern for hospitalized patients, particularly those in intensive care units (ICUs). The aims of this study were to investigate the prevalence of integrons and biofilm formation among P. aeruginosa and A. baumannii isolates collected from ICU and non-ICU inpatients. Materials and Methods: A total of 90 P. aeruginosa and 90 A. baumannii isolates were recovered from patients admitted into diverse units of Shahid Mohammadi hospital in Bandar Abbas from January to December 2014. Bacterial identification was carried out by phenotypic methods and PCR. Antibiotic susceptibility was measured by disk diffusion assay. The presence of Class 1, 2, and 3 integrons were evaluated by multiplex-PCR. Biofilm quantification was done by microtiter method. Results: The highest number of isolates (48%) were recovered from ICU patients. About 81% of P. aeruginosa isolates were sensitive to piperacillin/tazobactam and ticarcillin, while 60% were resistant to third generation of cephalosporins. In case of A. baumannii, all the isolates were sensitive to colistin, but 98% were resistant to other antibiotics (p≤0.05). Susceptibility to ceftazidime, ticarcillin, imipenem, and piperacillin/tazobactam were higher among isolates obtained from non-ICU patients. Class 1 integron was detected in 13.3% of the P. aeruginosa and 40% of the A. baumannii isolates, while Class 2 integron was harbored by 7 and 6.6% of the isolates, respectively. Furthermore, 23% of the A. baumannii and 12% of the P. aeruginosa isolates showed strong biofilm activity. Conclusion: Class 1 integron-positive isolates were resistant to three classes of antibiotics and predominantly observed in specimens collected from ICU patients showing strong biofilm.

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Molecular Detection of Class-D OXA Carbapenemase Genes in Biofilm and Non-Biofilm Forming Clinical Isolates of Acinetobacter baumannii

Cited by 33 publications

References 23 publications

Effect of iron on expression of efflux pump (adeABC) and quorum sensing (luxI, luxR) genes in clinical isolates of Acinetobacter baumannii

Effect of iron on expression of efflux pump (adeABC) and quorum sensing (luxI, luxR) genes in clinical isolates of Acinetobacter baumannii

Virulence Factor and Biofilm Formation in Clinical Enterococcal Isolates of the West of Iran

Prevalence of Class 1, 2, and 3 Integrons and Biofilm Formation in Pseudomonas aeruginosa and Acinetobacter baumannii among ICU and non-ICU Patients

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