Browsing by Author "Wasfi, Reham"

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Anaerobic biodegradation of anthracene by oral Firmicutes isolates from smokers and its potential pathway
(Elsevier Ltd., 2023-04) Wasfi, Reham; Moussa, Hams A; Bakr, Riham O; Abdeltawab, Nourtan F; Megahed, Salwa A
Exposure to polycyclic aromatic hydrocarbons (PAHs) from tobacco smoke has been linked to many negative health effects. Studies on the biodegradation of PAHs by human microbiota and detailed pathways for their anaerobic biodegradation are scarce despite their importance in getting rid of these toxic compounds. In a previous study for our group, we determined the ability of oral bacterial isolates in the anaerobic biodegradation of anthracene as a model of PAHs. Three isolates with the highest anthracene degradation ability were selected for the present study which include Limosilactobacillus fermentum, Veillonella parvula, and Streptococcus anginosus. In this study, we aimed at exploring and elucidating the anthracene anaerobic biodegradation pathways in selected Firmicutes oral isolates. Metabolites throughout the pathway were detected by gas chromatography coupled with mass spectroscopy (GC-MS) using anthracene as sole source of carbon. After incubation for 3 days, anthracene was undetected in the supernatant of L. fermentum and V. parvula, while a residual of 3% of anthracene was detected in presence of S. anginosus. Results revealed that anaerobic biodegradation by L. fermentum and V. parvula started with hydroxylation and dehydrogenation producing 9,10- anthraquinone and ended up with simpler structures such as catechol, while S. anginosus hydroxylation for anthracene resulted in the production of 1,2-anthracenediol and ended up with catechol and phthalic acid. The biodegradation of anthracene by oral bacteria could convert it to other toxic metabolites such as anthraquinone and catechol which were reported to have potential carcinogenic effects. Moreover, fatty acids detected as biodegradation metab- olites could be one of the causes of smokers’ heart-related diseases. Thus, this study explored oral metabolites resulting from smoking under anaerobic conditions towards elucidating the role of oral microbiota in health and disease states.
Antimicrobial activity of Vitex agnus-castus Essential Oil and Molecular Docking Study of Its Major Constituents
(Taylor & Francis, 2/26/2020) Bakr, Riham O.; Fayed, Marwa A.A.; Wasfi, Reham; Sonousi, Amr; Hassan, Rasha A.; Zaghloul, Soumaya S.
Antimicrobial resistance represents a public health problem worldwide that is associated with high morbidity and mortality which rose up the need for natural products as being an effective alternative. This study aims to evaluate the antimicrobial activity of the Vitex agnus-cactus L. essential oil (EO) towards bacterial and fungal strains of economic importance, besides, correlating its chemical constituents to the observed antimicrobial and antifungal activity using molecular docking. The chemical composition of essential oil was analyzed by gas chromatography-mass spectroscopy (GC-MS), where oxygenated monoterpenes (44.98 %) and monoterpenes (32.2 %) represented the major classes. Molecular docking study was carried out for the major identified essential oil constituents against bacterial protein targets, where, sabinene, 1,8 cineole, and linalool (the major oil constituents) acted on multi targets and reflected the effective antibacterial activity. Additionally, caryophyllene and verticiol showed a high binding affinity to Candida’s Farnesyl pyrophosphate synthase, a critical enzyme responsible for cell membrane integrity. V. agnus-cactus L. oil demonstrated itself as a powerful anticandidal agent providing a possible candidate in the pharmaceutical formulations
Biosurfactant from Nile Papyrus endophyte with potential antibiofilm activity against global clones of Acinetobacter baumannii
(Frontiers Media S.A., 2023-07) Amer, Mai A; Wasfi, Reham; Hamed, Samira M
Acinetobacter baumannii is a leading cause of biofilm-associated infections, particularly catheter-related bloodstream infections (CRBSIs) that are mostly recalcitrant to antimicrobial therapy. One approach to reducing the burden of CRBSIs is inhibiting biofilm formation on catheters. Owing to their prodigious microbial diversity, bacterial endophytes might be a valuable source of biosurfactants, which are known for their great capacity to disperse microbial biofilms. With this in mind, our study aimed to screen bacterial endophytes from plants growing on the banks of the River Nile for the production of powerful biosurfactants capable of reducing the ability of A. baumannii to form biofilms on central venous catheters (CVCs). This was tested on multidrug- and extensive drug- resistant (M/XDR) clinical isolates of A. baumannii that belong to high-risk global clones and on a standard strain of A. baumannii ATCC 19606. The drop collapse and oil dispersion assays were employed in screening the cell-free supernatants (CFS) of all endophytes for biosurfactant activity. Of the 44 bacterial endophytes recovered from 10 plants, the CFS of Bacillus amyloliquefaciens Cp24, isolated from Cyperus papyrus, showed the highest biosurfactant activity. The crude biosurfactant extract of Cp24 showed potent antibacterial activity with minimum inhibitory concentrations (MICs) ranging from 0.78 to 1.56 mg/ml. It also showed significant antibiofilm activity (p-value<0.01). Sub-MICs of the extract could reduce biofilm formation by up to 89.59%, while up to 87.3% of the preformed biofilms were eradicated by the MIC. A significant reduction in biofilm formation on CVCs impregnated with sub-MIC of the extract was demonstrated by CV assay and further confirmed by scanning electron microscopy. This was associated with three log10 reductions in adhered bacteria in the viable count assay. GC-MS analysis of the crude biosurfactant extract revealed the presence of several compounds, such as saturated, unsaturated, and epoxy fatty acids, cyclopeptides, and 3-Benzyl- hexahydro-pyrrolo [1, 2-a] pyrazine-1,4-dione, potentially implicated in the potent biosurfactant and antibiofilm activities. In the present study, we report the isolation of a B. amyloliquefaciens endophyte from the plant C. papyrus that produces a biosurfactant with potent antibiofilm activity against MDR/XDR global clones of A. baumannii. The impregnation of CVCs with the biosurfactant was demonstrated to reduce biofilms and, hence, proposed as a potential strategy for reducing CRBSIs.
Characterization of the bioactive constituents of Nymphaea alba rhizomes and evaluation of anti-biofilm as well as antioxidant and cytotoxic properties
(Journal of Medicinal Plants Research, 2016) Omar Bakr, Riham; Wasfi, Reham; Swilam, Noha; Ezz Sallam, Ibrahim
Anti-biofilm represents an urge to face drug resistance. Nymphaea alba L. flowers and rhizomes have been traditionally used in Ayurvedic medicine for dyspepsia, enteritis, diarrhea and as an antiseptic. This study was designed to identify the main constituents of Nymphaea alba L. rhizomes and their antibiofilm activity. 70% aqueous ethanolic extract (AEE) of N. alba rhizomes was analyzed by liquid chromatography, high resolution, mass spectrometry (LC-HRMS) for its phytoconstituents in the positive and negative modes in addition to column chromatographic separation. Sixty-four phenolic compounds were identified for the first time in N. alba rhizomes. Hydrolysable tannins represent the majority with identification of galloyl hexoside derivative, hexahydroxydiphenic (HHDP) derivatives, glycosylated phenolic acids and glycosylated flavonoids. Five phenolics have been isolated and identified as gallic acid and its methyl and ethyl ester in addition to ellagic acid and pentagalloyl glucose. Minimum inhibitory concentrations (MIC) and anti-biofilm activity for the extract and the major isolated compounds were determined. Radical scavenging activity using 2.2Di (4-tert-octylphenyl)-1- picryl-hydrazyl (DPPH) assay as well as cytotoxic activity using 3-(4, 5-dimethyl thiazol-2-yl)-2, 5- diphenyl tetrazolium bromide (MTT) assay have also been evaluated. MIC of N. alba rhizomes against Staphylococcus aureus was 0.25 mg/mL compared with 0.1 mg/mL for methyl gallate. The best reduction in biofilm formation (84.9%) as well as the best radical scavenging (IC50 3 µg/mL) and cytotoxic (IC50 9.61 ± 0.3 µg/mL) activities were observed with methyl gallate. This is the first study for in-depth characterization of phenolic compounds in N. alba rhizomes revealing it as a valuable source of phenolic compounds and promising anti-biofilm forming agent of natural origin.
Co-Existence of Carbapenemase-Encoding Genes in Acinetobacter baumannii from Cancer Patients
(ADIS, 11/12/2020) Wasfi, Reham; Rasslan, Fatma; Hassan, Safaa S.; Ashour, Hossam M.; Abd El-Rahman, Ola A.
Introduction: Acinetobacter baumannii is an opportunistic pathogen, which can acquire new resistance genes. Infections by carbapenem-re- sistant A. baumannii (CRAB) in cancer patients cause high mortality. Methods: CRAB isolates from cancer patients were screened for carbapenemase-encoding genes that belong to Ambler classes (A), (B), and (D), followed by genotypic characterization by enterobacterial-repetitive-Intergenic- consensus–polymerase chain reaction (ERIC–PCR) and multilocus-sequence-typing (MLST). Results: A total of 94.1% of CRAB isolates co- harbored more than one carbapenemase-en- coding gene. The genes blaNDM, blaOXA-23-like, and blaKPC showed the highest prevalence, with rates of 23 (67.7%), 19 (55.9%), and 17 (50%), respectively. ERIC-PCR revealed 19 patterns (grouped into 9 clusters). MLST analysis identi- fied different sequence types (STs) (ST-268, ST- 195, ST-1114, and ST-1632) that belong to the highly resistant easily spreadable International clone II (IC II). Genotype diversity indicated the dissemination of carbapenem-hydrolyzing, b-lactamase-encoding genes among genetically unrelated isolates. We observed a high preva- lence of metallo-b-lactamase (MBL)-encoding genes (including the highly-resistant blaNDM gene that is capable of horizontal gene transfer) and of isolates harboring multiple carbapene- mase-encoding genes from different classes. Conclusion: The findings are alarming and call for measures to prevent and control the spread of MBL-encoding genes among bacteria causing infections in cancer patients and other immunocompromised patient populations.
Editorial: Emerging strategies in combatting and managing bacterial biofilms
(Frontiers Media S.A., 2023-08) Wasfi, Reham; Zarkan, Ashraf; Hamed, Samira M
Numerous microbes use biofilm formation as a mean of survival. Biofilms are multicellular communities in which microorganisms are encased in a protective matrix that enables them to endure challenging environments and resist traditional therapies. The widespread existence of biofilm-forming bacteria in various settings, including healthcare facilities, is made possible by their capacity to colonize a variety of biotic and abiotic surfaces. They pose a serious threat to human health because they can develop increasing resistance to traditional antibiotics and spread morbidity through both device- and non- device (tissue)-associated infections, as reviewed by Zhao et al. This microbial phenotype consequently became a significant concern in several fields, including public health and medicine. Biofilms are involved in the pathogenicity of infectious diseases as well as the establishment of healthy microbiomes. Many bacterial species within the gut microbiome grow as biofilms, and disease outcome is greatly impacted by the location of the biofilms within the gastrointestinal tract (Miller et al., 2021). Hammouda et al. reported that hormonal drugs affect biofilm formation by selected gut microbiota such as Bifidobacterium longum, Limosilactobacillus reuteri, Bacteroides fragilis, and Escherichia coli, representing the four main phyla in the gut. Despite increasing the adhesion of L. reuteri to Caco-2/HT-29 cell line coculture, progesterone inhibited the biofilm development of the Gram-positive bacteria. In contrast, it increased the ability of Gram- negative bacteria to form biofilms and increased the adherence of B. fragilis to the cell lines coculture. Both estradiol and thyroxine displayed antibiofilm activity against L. reuteri. In the meantime, thyroxine boosted the capacity of E. coli to develop a biofilm. The implication of biofilm-related multi-drug resistance (MDR) in hospital-acquired infections is a significant issue with increased rates of patient mortality and morbidity as well as economic burden, including high healthcare expenses and extended hospital stays (Assefa and Amare, 2022). Hu et al. reported the ability of the emerging opportunistic nosocomial pathogen Elizabethkingia anophelis to form biofilms. MDR phenotype was also exhibited by all isolates. The authors concluded that biofilm development and antibiotic
High Counts and Anthracene Degradation Ability of Streptococcus mutans and Veillonella parvula Isolated From the Oral Cavity of Cigarette Smokers and Non-smokers
(Frontiers, 6/28/2021) Moussa, Hams A; Wasfi, Reham; Abdeltawab, Nourtan F; Megahed, Salwa A
The composition and metabolic functions of oral microbiota are affected by many factors including smoking leading to several health problems. Cigarette smoking is associated with changes in oral microbiota composition and function. However, it is not known if the depletion of certain bacterial genera and species is due to specific toxins in cigarette smoke, or indirectly due to competition for colonization with smoking-enriched bacteria. Therefore, the aim of this study was to determine the effect of cigarette smoking on the microbial prevalence and polycyclic aromatic hydrocarbons (PAHs) biodegradation of selected enriched and depleted oral bacteria from oral microbiota of smokers compared to that in non-smokers. Samples of oral rinse from smokers and non-smokers were collected (n = 23, 12 smokers and 11 non-smokers) and screened for oral bacterial strains of Streptococcus mutans, Lactobacillus spp., and Veillonella spp. Comparing counts, S. mutans, V. tobetsuensis, and V. dispar showed higher counts in smokers compared to non-smokers while the Lactobacillus spp. were higher in non-smokers. Lactobacillus fermentum was prevalent in smokers, representing 91.67% of the total Lactobacillus spp. isolates. The biodegradation potential of anthracene; a representative of PAHs of collected isolates, in single and mixed cultures, was assayed with anthracene as the sole source of carbon using 2,6-dichlorophenol indophenol (2,6-DCPIP) as indicator. S. mutans isolates recovered from smokers showed higher degradation of anthracene compared to those recovered from non-smokers. The anaerobic anthracene biodegradation activity of V. parvula isolates from non-smokers was the highest among all isolates of the three recovered genera from the same subject. The anthracene biodegradation potential of Lactobacillus spp. was variable. Combinations of isolated bacteria in co-cultures showed that Lactobacillus spp. interfered with anthracene biodegradation ability along with the viable counts of S. mutans and Veillonella spp. In conclusion, oral dysbiosis due to cigarette smoking was observed not only due to changes in oral bacterial relative abundance but also extended to bacterial functions Frontiers in Microbiology | www.frontiersin.org 1 June 2021 | Volume 12 | Article 661509 Moussa et al. Anthracene Biodegradation by Oral Bacteria such as anthracene biodegradation tested in this study. Microbe-microbe interactions changed the anthracene biodegradation potential and growth of the microbial mixture compared to their corresponding single isolates, and these changes differ according to the constituting bacteria.
Hormonal drugs: Influence on growth, biofilm formation, and adherence of selected gut microbiota
(Frontiers Media S.A., 2023-03) Hammouda, Zainab K; Wasfi, Reham; Abdeltawab, Nourtan F
Many studies have reported the influence of hormonal drugs on gut microbiota composition. However, the underlying mechanism of this interaction is still under study. Therefore, this study aimed to evaluate the possible in vitro changes in selected members of gut bacteria exposed to oral hormonal drugs used for years. Selected members of gut bacteria were Bifidobacterium longum, Limosilactobacillus reuteri, Bacteroides fragilis, and Escherichia coli representing the four main phyla in the gut. Selected hormonal drugs used for a long time were estradiol, progesterone, and thyroxine. The effect of intestinal concentrations of these drugs on the selected bacterial growth, biofilm formation, and adherence to Caco-2/HT-29 cell line was assessed. Short-chain fatty acids (SCFAs) have been included in host functions including the gut, immune and nervous functions; thus, the drug’s effects on their production were assayed using High- Performance Liquid Chromatography. Sex steroids significantly increased the growth of all tested bacteria except B. longum, similarly, thyroxine increased the growth of tested Gram-negative bacteria however reducing that of tested Gram-positive bacteria. The effect of drugs on biofilm formation and bacterial adherence to cell lines cocultures was variable. Progesterone decreased the biofilm formation of tested Gram-positive bacteria, it nevertheless increased L. reuteri adherence to Caco-2/ HT-29 cell line cell lines coculture. By contrast, progesterone increased biofilm formation by Gram-negative bacteria and increased adherence of B. fragilis to the cell lines coculture. Moreover, thyroxine and estradiol exhibited antibiofilm activity against L. reuteri, while thyroxine increased the ability of E. coli to form a biofilm. Moreover, hormones affected bacterial adherence to cell lines independently of their effect on hydrophobicity suggesting other specific binding factors might contribute to this effect. Tested drugs affected SCFAs production variably, mostly independent of their effect on bacterial growth. In conclusion, our results showed that the microbiota signature associated with some hormonal drug consumption could be the result of the direct effect of these drugs on bacterial growth, and adherence to enterocytes besides the effect of these drugs on the host tissue targets. Additionally, these drugs affect the production of SCFAs which could contribute to some of the side effects of these drugs.
Indole Derivatives Obtained from Egyptian Enterobacter sp. Soil Isolates Exhibit Antivirulence Activities against Uropathogenic Proteus mirabilis
(MDPI, 3/29/2021) Amer, Mai A; Wasfi, Reham; Attia, Ahmed S; Ramadan, Mohamed A
Proteus mirabilis is a frequent cause of catheter associated urinary tract infections (CAUTIs). Several virulence factors contribute to its pathogenesis, but swarming motility, biofilm formation, and urease activity are considered the hallmarks. The increased prevalence in antibiotic resistance among uropathogens is alarming and requires searching for new treatment alternatives. With this in mind, our study aims to investigate antivirulence activity of indole derivatives against multidrug resistant P. mirabilis isolates. Ethyl acetate (EtOAc) extracts from Enterobacter sp. (rhizobacterium), isolated from Egyptian soil samples were tested for their ability to antagonize the virulence capacity and biofilm activity of P. mirabilis uropathogens. Extracts of two Enterobacter sp. isolates (coded Zch127 and Cbg70) showed the highest antivirulence activities against P. mirabilis. The two promising rhizobacteria Zch127 and Cbg70 were isolated from soil surrounding: Cucurbita pepo (Zucchini) and Brassica oleracea var. capitata L. (Cabbage), respectively. Sub-minimum inhibitory concentrations (Sub-MICs) of the two extracts showed potent antibiofilm activity with significant biofilm reduction of ten P. mirabilis clinical isolates (p-value < 0.05) in a dose-dependent manner. Interestingly, the Zch127 extract showed anti-urease, anti-swarming and anti-swimming activity against the tested strains. Indole derivatives identified represented key components of indole pyruvate, indole ac- etamide pathways; involved in the synthesis of indole acetic acid. Additional compounds for indole acetonitrile pathway were detected in the Zch127 extract which showed higher antivirulence activity. Accordingly, the findings of the current study model the feasibility of using these extracts as promis- ing antivirulence agent against the P. mirabilis uropathogens and as potential therapy for treatment of urinary tract infections (UTIs).
Novel linezolid loaded bio-composite films as dressings for effective wound healing: experimental design, development, optimization, and antimicrobial activity
(Informa Healthcare, 2022-10) Ghataty, Dina Saeed; Amer, Reham Ibrahim; Wasfi, Reham; Shamma, Rehab Nabil
Biphasic release bio-composite films of the low water-soluble drug, linezolid (LNZ), were formulated using the solvent casting technique. Different polymers and plasticizers (gelatin, Tween 80, polyethylene glycol 400, and glycerol) were assessed for the preparation of bio-composite films. An I-optimal design was applied for the optimization and to study the impact of polymer concentration (X1), plasticizer concentration (X2), polymer type (X3), and plasticizer type (X4) on different LNZ-loaded bio-composite films. The film thickness, moisture content, mechanical properties, swelling index, and percentage of drug release at fixed times opted as dependent variables. Results demonstrated a significant effect of all independent variables on the drug release from the prepared bio-composite films. The plasticizer concentration significantly increased the thickness, moisture content, elongation at break, swelling index, and in vitro drug release and significantly reduced the tensile strength. The optimized LNZ-loaded bio-composite film comprised of 15% Tween 80 and 30% PEG 400 was highly swellable, elastic, acceptable tensile properties, safe, maintained a moist environment, and indicated great antimicrobial activity against both Staphylococcus aureus (ATCC® 25922) and methicillin-resistant Staphylococcus aureus (MRSA), which are common wound infectious bacteria. The present study concludes that the optimized LNZ-loaded bio-composite film was successfully designed with fast drug release kinetics and it could be regarded as a promising novel antimicrobial wound dressing formulation.
Phenotypic and Molecular Characterization of Plasmid Mediated AmpC β-Lactamases among Escherichia coli, Klebsiella spp., and Proteus mirabilis Isolated from Urinary Tract Infections in Egyptian Hospitals
(HINDAWI LTD, 2014) M Helmy, Mai; Wasfi, Reham
The incidence of resistance by Enterobacteriaceae to β-lactam/β-lactamase inhibitors combination is increasing in Egypt. Three phenotypic techniques, comprising AmpC disk diffusion and inhibition dependent methods using phenylboronic acid (PBA) and cloxacillin, were compared to PCR based method for detection of plasmid mediated AmpC β-lactamase in common urinary tract isolates. A total of 143 isolates, including E. coli, Klebsiella pneumonia, and Proteus mirabilis, were collected from urinary tract infections cases in Egyptian hospitals. Plasmid encoded AmpC genes were detected by PCR in 88.46% of cefoxitin resistant isolates. The most prevalent AmpC gene family was CIT including CMY-2, CMY-4, and two CMY-2 variants. The second prevalent gene was DHA-1 which was detected in E. coli and Klebsiella pneumonia. The genes EBC, FOX, and MOX were also detected but in small percentage. Some isolates were identified as having more than one pAmpC gene. The overall sensitivity and specificity of phenotypic tests for detection of AmpC β-lactamase showed that AmpC disk diffusion and inhibition dependent method by cloxacillin were the most sensitive and the most specific disk tests. PCR remains the gold standard for detection of AmpC β-lactamases. This study represents the first report of CMY-2 variants of CMY-42 and CMY-102 β-lactamase-producing E. coli, Klebsiella pneumonia, and Proteus mirabilis isolates in Egypt
Proteus mirabilis Biofilm: Development and Therapeutic Strategies
(Frontier, 2020-08) Wasfi, Reham; Hamed, Samira; Amer, Mai Abdel wahed; Fahmy, Lamiaa Ismail
Proteus mirabilis is a Gram negative bacterium that is a frequent cause of catheter-associated urinary tract infections (CAUTIs). Its ability to cause such infections is mostly related to the formation of biofilms on catheter surfaces. In order to form biofilms, P. mirabilis expresses a number of virulence factors. Such factors may include adhesion proteins, quorum sensing molecules, lipopolysaccharides, efflux pumps, and urease enzyme. A unique feature of P. mirabilis biofilms that build up on catheter surfaces is their crystalline nature owing to their ureolytic biomineralization. This leads to catheter encrustation and blockage and, in most cases, is accompanied by urine retention and ascending UTIs. Bacteria embedded in crystalline biofilms become highly resistant to conventional antimicrobials as well as the immune system. Being refractory to antimicrobial treatment, alternative approaches for eradicating P. mirabilis biofilms have been sought by many studies. The current review focuses on the mechanism by which P. mirabilis biofilms are formed, and a state of the art update on preventing biofilm formation and reduction of mature biofilms. These treatment approaches include natural, and synthetic compounds targeting virulence factors and quorum sensing, beside other strategies that include carrier-mediated diffusion of antimicrobials into biofilm matrix. Bacteriophage therapy has also shown successful results in vitro for combating P. mirabilis biofilms either merely through their lytic effect or by acting as facilitators for antimicrobials diffusion.
The RND Efflux Pump Gene Expression in the Biofilm Formation of Acinetobacter baumannii
(Multidisciplinary Digital Publishing Institute (MDPI), 2023-02) Abd El-Rahman, Ola A; Rasslan, Fatma; Hassan, Safaa S; Ashour, Hossam M; Wasfi, Reham
Multidrug resistant (MDR) Acinetobacter baumannii is a critical opportunistic pathogen in healthcare-associated infections (HAI). This is attributed to several factors, including its ability to develop biofilms that can enhance antimicrobial resistance (AMR) in addition to creating an environment for horizontal transfer of antibiotic resistance genes. The role of the efflux pump in biofilm formation is important for studies on alternative treatments for biofilms. One of the significant efflux pump families is the RND efflux pump family, which is common in Gram negative bacteria. The aim is to study the role of the RND efflux pump in biofilm formation by A. baumannii. The biofilm formation potential of thirty-four MDR A. baumannii isolates was evaluated by crystal violet assays. The effect of efflux pump inhibition and activation was studied using the efflux pump inhibitor carbonyl cyanide 3-chlorophenylhydrazone (CCCP) and the RND efflux pump substrate levofloxacin (at sub-MIC), respectively. The isolates were genotypically grouped by enterobacterial repetitive intergenic consensus (ERIC) typing and the expression of adeABC, adeFGH, and adeIJK efflux pump genes was measured by qPCR. Overall, 85.2% (29/34) of isolates were biofilm producers (the phenotype was variable including strong and weak producers). Efflux pump inhibition by CCCP reduced the biofilm formation significantly (p < 0.05) in 20.5% (7/34) of some isolates, whereas sub-MICs of the substrate levofloxacin increased biofilm formation in 17.6% (6/34) of other isolates. Overexpression of the three RND efflux pump genes was detected in five out of eleven selected isolates for qPCR with remarkable overexpression in the adeJ gene. No correlation was detected between the biofilm phenotype pattern and the RND efflux pump gene expression in biofilm cells relative to planktonic cells. In conclusion, the role of the RND efflux pumps AdeABC, AdeFGH, and AdeIJK in biofilm formation does not appear to be pivotal and the expression differs according to the genetic background of each strain. Thus, these pumps may not be a promising target for biofilm inhibition.
Silicone Foley catheters impregnated with microbial indole derivatives inhibit crystalline biofilm formation by Proteus mirabilis
(Frontiers Media S.A., 2022-09-02) Amer, Mai A; Ramadan, Mohamed A; Attia, Ahmed S; Wasfi, Reham
Proteus mirabilis is a common causative agent for catheter-associated urinary tract infections (CAUTI). The crystalline biofilm formation by P. mirabilis causes catheter encrustation and blockage leading to antibiotic treatment resistance. Thus, biofilm formation inhibition on catheters becomes a promising alternative for conventional antimicrobial-based treatment that is associated with rapid resistance development. Our previous work has demonstrated the in vitro antibiofilm activity of microbial indole derivatives against clinical isolates of P. mirabilis. Accordingly, we aim to evaluate the capacity of silicone Foley catheters (SFC) impregnated with these indole derivatives to resist biofilm formation by P. mirabilis both phenotypically and on the gene expression level. Silicon Foley catheter was impregnated with indole extract recovered from the supernatant of the rhizobacterium Enterobacter sp. Zch127 and the antibiofilm activity was determined against P. mirabilis (ATCC 12435) and clinical isolate P8 cultured in artificial urine. The indole extract at sub- minimum inhibitory concentration (sub-MIC=0.5X MIC) caused a reduction in biofilm formation as exhibited by a 60-70% reduction in biomass and three log10 in adhered bacteria. Results were confirmed by visualization by scanning electron microscope. Moreover, changes in the relative gene expression of the virulence genes confirmed the antibiofilm activity of the indole extract against P. mirabilis. Differential gene expression analysis showed that extract Zch127 at its sub-MIC concentration significantly down-regulated genes associated with swarming activity: umoC, flhC, flhD, flhDC, and mrpA (p< 0.001). In addition, Zch127 extract significantly down-regulated genes associated with polyamine synthesis: speB and glnA (p< 0.001), as well as the luxS gene associated with quorum sensing. Regulatory genes for capsular polysaccharide formation; rcsB and rcsD were not significantly affected by the presence of the indole derivatives. Furthermore, the impregnated catheters and the indole extract showed minimal or no cytotoxic effect against human fibroblast cell lines indicating the safety of this intervention. Thus, the indole-impregnated catheter is proposed to act as a suitable and safe strategy for reducing P. mirabilis CAUTIs.
Silicone Foley catheters impregnated with microbial indole derivatives inhibit crystalline biofilm formation by Proteus mirabilis
(Frontiers Media S.A., 2022-09) Amer, Mai A; Ramadan, Mohamed A; Attia, Ahmed S; Wasfi, Reham
Proteus mirabilis is a common causative agent for catheter-associated urinary tract infections (CAUTI). The crystalline biofilm formation by P. mirabilis causes catheter encrustation and blockage leading to antibiotic treatment resistance. Thus, biofilm formation inhibition on catheters becomes a promising alternative for conventional antimicrobial-based treatment that is associated with rapid resistance development. Our previous work has demonstrated the in vitro antibiofilm activity of microbial indole derivatives against clinical isolates of P. mirabilis. Accordingly, we aim to evaluate the capacity of silicone Foley catheters (SFC) impregnated with these indole derivatives to resist biofilm formation by P. mirabilis both phenotypically and on the gene expression level. Silicon Foley catheter was impregnated with indole extract recovered from the supernatant of the rhizobacterium Enterobacter sp. Zch127 and the antibiofilm activity was determined against P. mirabilis (ATCC 12435) and clinical isolate P8 cultured in artificial urine. The indole extract at sub-minimum inhibitory concentration (sub-MIC=0.5X MIC) caused a reduction in biofilm formation as exhibited by a 60-70% reduction in biomass and three log10 in adhered bacteria. Results were confirmed by visualization by scanning electron microscope. Moreover, changes in the relative gene expression of the virulence genes confirmed the antibiofilm activity of the indole extract against P. mirabilis. Differential gene expression analysis showed that extract Zch127 at its sub-MIC concentration significantly down-regulated genes associated with swarming activity: umoC, flhC, flhD, flhDC, and mrpA (p< 0.001). In addition, Zch127 extract significantly down-regulated genes associated with polyamine synthesis: speB and glnA (p< 0.001), as well as the luxS gene associated with quorum sensing. Regulatory genes for capsular polysaccharide formation; rcsB and rcsD were not significantly affected by the presence of the indole derivatives. Furthermore, the impregnated catheters and the indole extract showed minimal or no cytotoxic effect against human fibroblast cell lines indicating the safety of this intervention. Thus, the indole-impregnated catheter is proposed to act as a suitable and safe strategy for reducing P. mirabilis CAUTIs. Copyright © 2022 Amer, Ramadan, Attia and Wasfi.
State of the art in epitope mapping and opportunities in COVID-19
(Future Medicine Ltd., 2023-03) Hamed, Samira M; Sakr, Masarra M; El-Housseiny, Ghadir S; Wasfi, Reham; Aboshanab, Khaled M
The understanding of any disease calls for studying specific biological structures called epitopes. One important tool recently drawing attention and proving efficiency in both diagnosis and vaccine development is epitope mapping. Several techniques have been developed with the urge to provide precise epitope mapping for use in designing sensitive diagnostic tools and developing rpitope-based vaccines (EBVs) as well as therapeutics. In this review, we will discuss the state of the art in epitope mapping with a special emphasis on accomplishments and opportunities in combating COVID-19. These comprise SARS-CoV-2 variant analysis versus the currently available immune-based diagnostic tools and vaccines, immunological profile-based patient stratification, and finally, exploring novel epitope targets for potential prophylactic, therapeutic or diagnostic agents for COVID-19. Plain language summary: Epitope mapping is an important tool recently proving efficiency in both diagnosis and vaccine development. Several epitope mapping techniques have been developed for designing sensitive diagnostic tools and developing rpitope-based vaccines (EBVs) as well as therapeutics. In this review, we will discuss the state of the art in epitope mapping, emphasizing accomplishments and opportunities in combating COVID-19. These comprise SARS-CoV-2 variant analysis versus the currently available immune-based diagnostic tools and vaccines and exploring novel epitope targets for potential prophylactic, therapeutic or diagnostic agents for COVID-19. First draft submitted: 29 July 2022; Accepted for publication: 15 February 2023; Published online: 6 March 2023