Lecithinase-producing bacteria in commercial and home-made foods: Evaluation of toxic properties and identification of potent producers

Sharaf, Eman F.; El‐Sayed, Wael S.; Abosaif, Roaa M.

doi:10.1016/j.jtusci.2014.03.006

Cited by 17 publications

(16 citation statements)

References 22 publications

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“…Undoubtedly, lipase plays a supreme role in the severity of infection (El-baz et al, 2016). The toxic effect of lecithinase relies on the fact that the enzyme usually acts on cell membranes, either perforating them, resulting in cell lysis or by breaking down the phospholipids (Sharaf et al, 2014). Shetty et al (2009) reported that lecithinase causes lysis of red blood cells, myocytes, fibroblasts platelets, and leukocytes.…”

Section: Discussionmentioning

confidence: 99%

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Antibacterial potential of some seaweeds species to combat biofilm-producing multi-drug resistant Staphylococcus aureus of Nile tilapia

et al. 2019

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T HERE is an increasing worldwide demand for seafood due to the awareness of fish as an important protein source for a growing population. However, the diseases caused by multi-drug resistant (MDR) bacterial infections and the low survival rate of the fish represent significant challenges to fish farmers. The virulence and pathogenicity of bacteria are often enhanced when growing as a biofilm. Therefore, a variety of new antimicrobial drugs has attracted wide attention in treating fish pathogen bacteria. Herein, the efficiency of macroalgal extracts as an antibacterial agent against MDR Staphylococcus aureus bacteria isolated from Nile tilapia (Oreochromis niloticus) was studied. Out of 200 bacterial isolates, 50 strains were identified as S. aureus. Of these strains, 37 were MDR and showed a potential role in the production of virulence factors, including staphylokinase (70.2%), lecithinase (81%), protease (56.7%) and lipase (59.4%). Significant production of biofilm virulence factor by MDR S. aureus strains was also observed from the quantitative and qualitative analysis. Four algal species namely Jania rubens, Ulva lactuca, Sargassum vulgare, and Sargassum fusiforme were tested for their antibacterial activity against MDR S. aureus strains. Of those, S. vulgare diethyl ether extract showed the highest antibacterial. In addition, GC-MS analysis revealed 20 identified components in S. vulgare diethyl ether extract, in which Longifolene was dominant (16.5%). This study thus established the possibility of developing an antibacterial agent to combat developing MDR S. aureus and biofilm-related infections in Nile tilapia.

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Section: Discussionmentioning

confidence: 99%

“…Lecithinase activity of the tested isolates was detected on egg yolk agar plates (Sharaf et al, 2014). The plates were prepared by the addition of 10% of egg yolk suspension to prewarmed (45°C) tryptic soy agar (TSA) supplemented with 1% NaCl.…”

Section: Detection Of Lecithinase Productionmentioning

confidence: 99%

Antibacterial potential of some seaweeds species to combat biofilm-producing multi-drug resistant Staphylococcus aureus of Nile tilapia

et al. 2019

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“…Lecithinase production was tested on a modified medium as described previously (Oladipo et al, 2008). Lecithinase was detected according to the standard method (Sharaf et al, 2014), in which 1 ml of each bacterial culture, having cell density of 6 × 10 8 CFU/ml was inoculated into test tubes containing corn millet broth and incubated for 24 h at 37 • C. After incubation, the cultures were centrifuged at 2500 rpm for 15 min to obtain a cellfree filtrate, and 100 µl of the filtrate was transferred into 10-mm wells made centrally in the egg-yolk agar plates and incubated for 24 h at 37 • C. Opaque zones were measured as indicators of lecithinase production. Gelatinase production was detected by stab inoculating the test strain on nutrient agar supplemented with 3% gelatin kept at 37 • C for 24 h followed by refrigeration at 4 • C for 30 min.…”

Section: Analysis Of Extracellular Enzymesmentioning

confidence: 99%

Comparative Metagenomic Analysis of Two Alkaline Hot Springs of Madhya Pradesh, India and Deciphering the Extremophiles for Industrial Enzymes

et al. 2021

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Hot springs are considered to be a unique environment with extremophiles, that are sources of industrially important enzymes, and other biotechnological products. The objective of this study was to undertake, analyze, and characterize the microbiome of two major hot springs located in the state of Madhya Pradesh explicitly, Chhoti Anhoni (Hotspring 1), and Badi Anhoni (Hotspring 2) to find out the inhabitant microbial population, and their functional characteristics. The taxonomic analysis of the microbiome of the hot springs revealed the phylum Proteobacteria was the most abundant taxa in both the hot-springs, however, its abundance in hot-spring 1 (~88%) was more than the hot-spring 2 (~52%). The phylum Bacteroides (~10–22%) was found to be the second most abundant group in the hot-springs followed by Spirocheates (~2–11%), Firmicutes (~6–8%), Chloroflexi (1–5%), etc. The functional analysis of the microbiome revealed different features related to several functions including metabolism of organics and degradation of xenobiotic compounds. The functional analysis showed that most of the attributes of the microbiome was related to metabolism, followed by cellular processes and environmental information processing functions. The functional annotation of the microbiomes at KEGG level 3 annotated the sequences into 279 active features that showed variation in abundance between the hot spring samples, where hot-spring 1 was functionally more diverse. Interestingly, the abundance of functional genes from methanogenic bacteria, was higher in the hot-spring 2, which may be related to the relatively higher pH and temperature than Hotspring 1. The study showed the presence of different unassigned bacterial taxa with high abundance which indicates the potential of novel genera or phylotypes. Culturable isolates (28) were bio-prospected for industrially important enzymes including amylase, protease, lipase, gelatinase, pectinase, cellulase, lecithinase, and xylanase. Seven isolates (25%) had shown positive results for all the enzyme activities whereas 23 isolates (82%) produced Protease, 27 isolates (96%) produced lipase, 27 isolates produced amylase, 26 isolates (92%) produced cellulase, 19 isolates (67%) produced pectinase, 19 isolates (67%) could produce lecithinase, and 13 isolates (46%) produced gelatinase. The seven isolates, positive for all the enzymes were analyzed further for quantitative analysis and identified through molecular characterization.

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“…We have also noticed that the loss of lecithinase expression by the B. cereus colonies: the typical white halo around colonies on these plates was absent. Studies have demonstrated that the lecithinase production of B. cereus is substrate dependent [33]. Kushner [34,35], for example, reported that the presence of alcohols and enzymes in the growth medium inhibited the synthesis of lecithinase by growing B. cereus.…”

Section: Best Plating Media For Use With T80mentioning

confidence: 99%

Optimized Culture Conditions for the Detection of Selected Strains of Bacillus in Eye Creams

et al. 2017

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Although eye area cosmetics contain preservatives, contamination can still occur during or after manufacture or through use. Understanding the likelihood of bacterial survival in eye creams begins with sensitive and accurate methods for the detection of bacterial contamination; therefore, we investigated optimal culture conditions, including neutralizers, dilution broths, and selective media for the detection of Bacillus in eye cream. Samples of three different brands of eye creams were first mixed with Tween 80, Tween 20, or a blend of Tween 60 and Span 80, then neutralized and non-neutralized samples were individually inoculated with B. cereus strains, B. mycoides, a mislabeled B. megaterium, B. subtilis or B. thuringiensis at a final concentration of 5 log CFU/g. The inoculated samples, with and without neutralizers, were spiral-plated and incubated at 30 • C for 24 h to 48 h. Presumptive colonies of Bacillus were enumerated on U. S. Food and Drug Administration Bacteriological Analytical Manual (FDA-BAM) referenced agars Bacillus cereus rapid agar (BACARA) and mannitol-egg yolk-polymixin agar (MYP). Our results show significant differences among the neutralizers, plates, and products. The combination of Tryptone-Azolectin-Tween and Tween 80 (TAT and T80) produced higher levels of Bacillus, estimated at 4.18 log CFU/g compared to growth on Modified letheen broth and Tween 80, which produced 3.97 log CFU/g (P < 0.05). Colony counts of B. cereus cells on MYP agar were significantly higher, than those on BACARA agar, showing an average of 4.25 log CFU/g versus 3.84 log CFU/g, respectively (P < 0.05). The growth of the strain mislabeled B. megaterium ATCC 6458 on B. cereus selective agars BACARA and MYP agar led us to further investigations. We identified bi-pyramidal crystals among colonies of the strain, and subsequent PCR identified the cry 1 gene, indicating that strain was actually B. thuringiensis subps. kurstaki.

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Lecithinase-producing bacteria in commercial and home-made foods: Evaluation of toxic properties and identification of potent producers

Cited by 17 publications

References 22 publications

Antibacterial potential of some seaweeds species to combat biofilm-producing multi-drug resistant Staphylococcus aureus of Nile tilapia

Antibacterial potential of some seaweeds species to combat biofilm-producing multi-drug resistant Staphylococcus aureus of Nile tilapia

Comparative Metagenomic Analysis of Two Alkaline Hot Springs of Madhya Pradesh, India and Deciphering the Extremophiles for Industrial Enzymes

Optimized Culture Conditions for the Detection of Selected Strains of Bacillus in Eye Creams

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