Adherence assays and slime production of Staphylococcus aureus strains after their incubation in seawater microcosms

Békir, Karima; Abdallah, Fethi Ben; Ellafi, Ali; Bakhrouf, Amina

doi:10.1007/s13213-011-0200-2

Cited by 12 publications

(12 citation statements)

References 24 publications

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“…Among the S. epidermidis was a slime-producer developing almost black colonies on CRA plates ( Figure 6). Indeed, slime production play an important role in the pathogenesis of infections caused by different micro-organismes (Bekir et al, 2010) and is considered to be a significant virulence factor for some staphylococci (Bekir et al, 2011) as well as for Aeromonas spp which indicates the high-risk source contamination (Sechi et al, 2002). Slimes are generally polysaccharidic materials, although other poly- mers may also be present.…”

Section: Resultsmentioning

confidence: 99%

Biodegradation of azo and triphenylmethanes dyes: Cytotoxicity of dyes, slime production and enzymatic activities of Staphylococcus epidermidis isolated from industrial wastewater

Ayed¹,

Kouidhi²,

Békir³

et al. 2013

Afr. J. Microbiol. Res.

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In view of compliance with increasingly stringent environmental legislation imposed by regional, national and supranational (for example, European Union) authorities, innovative environmental technologies for the treatment of dye-contaminated effluents are necessary in the color industry. In this study, azo (methyl orange (MO) and methyl red (MR)) and triphenylmethanes (malachite green (MG), fushin (F) and crystal violet (CV)) dyes were subjected to distinct treatment strains following an initial qualitative characterization. The effectiveness of their biodegradation using Staphylococcus epidermidis strain was compared with respect to parameters such as residual color, and toxicity on human cells. The Hep-2 cells were exposed to three azo and two triphenylmethane dyes at various concentrations. After 72 h exposure, the protein contents of the samples compared to the protein contents of non-exposed cells were measured. The level of protein content indicates the viability of the cells. The IC20 values show the limiting value of toxicity. The IC50 values before biodegradation show whether samples are clearly toxic. The IC50 value for the azo dyes (MO, MR) were 65 and 10 μg/ml, the IC20 value were 10 and 5 μg/ml. The IC50 for the triphenylmethane dyes (MG, F and CV) were 35, 25 and 30 μg/ml, the IC20 value were 5, 5 and 10 μg/ml. The viability of the cells was good, the protein content of the samples being over 80% compared to the non-exposed cells. The Hep-2 cell test indicated the toxicity of pure dyes before biodegradation; the dyes after decolorization had no adverse effect. The human keratinocyte Hep-2 cells seem to be a useful tool for the study of the purity/toxicity of dyes and other substances applied to textiles. In addition, the initial cytotoxicity of dyes was still present after the biodegradation, while it was completely removed through the bacterial treatment. Our results show that S. epidermidis was a slime-producer developing almost black colonies on Congo red agar plate. A significant increase in azoreductase, lignin peroxidase and laccase activities in the cells were obtained after complete decolorization.

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Section: Resultsmentioning

confidence: 99%

Biodegradation of azo and triphenylmethanes dyes: Cytotoxicity of dyes, slime production and enzymatic activities of Staphylococcus epidermidis isolated from industrial wastewater

Ayed¹,

Kouidhi²,

Békir³

et al. 2013

Afr. J. Microbiol. Res.

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“…They were visualized under ultraviolet transillumination, and photographed using Gel Doc XR apparatus (Biorad, USA) (Bekir et al . ).…”

Section: Methodsmentioning

confidence: 97%

Exploring bioaugmentation strategies for azo dye CI Reactive Violet 5 decolourization using bacterial mixture: dye response surface methodology

Ayed

Békir²,

Achour³

et al. 2016

Water & Environment J

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The use of response surface methodology based on statistical design of experiments is becoming increasingly widespread in several sciences such as analytical and environmental chemistry. In the present study, the decolourization and the degradation efficiency of CI Reactive Violet 5 (CIRV5) was studied using a novel bacterial consortium. CIRV5 (1000 p.p.m.) biodegradation was investigated under shaking condition in mineral salt medium solution (MSM) at a 7.5 pH and a 25°C temperature. The degradation pathways were also predicted, using UV‐visible spectroscopy analysis. Under optimal conditions, the bacterial consortium was able to decolourize the dye completely (>99%) within 8 h. The colour and chemical oxygen demand (COD) removal were 99.29 and 94.93%, respectively. Polymerase chain reaction (PCR) technique was utilized to detect the adhesin genes ‘icaA’ and ‘icaD.’ Our results showed that Staphylococcus aureus had a high decolourization capacity. Phytotoxicity study using Triticum turgidum ssp durum showed the no toxicity of the produced products.

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“…The used primers were specific to Sa442 gene (5′-CGTAATGAGATTTCAGTAGATAATACAACA-3′ and 5′-AATCTTTGTCGGTACACGATATTCTTCACG-3′) (Murdoch et al 2004;Bekir et al 2011). The PCR was performed using the following thermal cycles: an initial denaturation step at 94°C for 5 min followed by 35 cycles (94°C for 90 s, 57°C for 30 s, and 72°C for 90 s), followed by a final extension step at 72°C for 10 min.…”

Section: Pcr Confirmation Of S Aureus Strainmentioning

confidence: 99%

“…This behavior can be attributed to the conservation of surface antigen integrity in stressed S. aureus. According to Bekir et al (2011), stress induces the reduction of the cell size, the increase in cell number, the lost of small granules and inclusion bodies, the lost of the distinct three-layered integrity of the outer membrane, peptidoglycan, and the inner membrane to retain only remnants of those structures, the compression of the nuclear region into the cell center surrounded by a denser cytoplasm, and the formation of extended or convoluted structures from the cell wall which are pulled away from the cell membrane. In previous work, it was shown that stress phenomenon can lead to the alteration of the S. bovismorbificans envelope (Bakhrouf et al 2008).…”

Section: Detection Of Bacteria Cells Using Electrochemical Impedance mentioning

confidence: 99%

Electrochemical impedance immunosensor for rapid detection of stressed pathogenic Staphylococcus aureus bacteria

Békir¹,

Barhoumi²,

Braiek³

et al. 2015

Environ Sci Pollut Res

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In this work, we report the adaptation of bacteria to stress conditions that induce instability of their cultural, morphological, and enzymatic characters, on which the identification of pathogenic bacteria is based. These can raise serious issues during the characterization of bacteria. The timely detection of pathogens is also a subject of great importance. For this reason, our objective is oriented towards developing an immunosensing system for rapid detection and quantification of Staphylococcus aureus. Polyclonal anti-S. aureus are immobilized onto modified gold electrode by self-assembled molecular monolayer (SAM) method. The electrochemical performances of the developed immunosensor were evaluated by impedance spectroscopy through the monitoring of the charge transfer resistance at the modified solid/liquid interface using ferri-/ferrocyanide as redox probe. The developed immunosensor was applied to detect stressed and resuscitate bacteria. As a result, a stable and reproducible immunosensor with sensitivity of 15 kΩ/decade and a detection limit of 10 CFU/mL was obtained for the S. aureus concentrations ranging from 10(1) to 10(7) CFU/mL. A low deviation in the immunosensor response (±10 %) was signed when it is exposed to stressed and not stressed bacteria.

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Adherence assays and slime production of Staphylococcus aureus strains after their incubation in seawater microcosms

Cited by 12 publications

References 24 publications

Biodegradation of azo and triphenylmethanes dyes: Cytotoxicity of dyes, slime production and enzymatic activities of Staphylococcus epidermidis isolated from industrial wastewater

Biodegradation of azo and triphenylmethanes dyes: Cytotoxicity of dyes, slime production and enzymatic activities of Staphylococcus epidermidis isolated from industrial wastewater

Exploring bioaugmentation strategies for azo dye CI Reactive Violet 5 decolourization using bacterial mixture: dye response surface methodology

Electrochemical impedance immunosensor for rapid detection of stressed pathogenic Staphylococcus aureus bacteria

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