Antifungal and antibiofilm effects of probiotic Lactobacillus salivarius, zinc nanoparticles, and zinc nanocomposites against Candida albicans from Nile tilapia (Oreochromis niloticus), water and humans.

Introduction: Candida albicans (C. albicans) can form biofilms; a critical virulence factor that provides effective protection from commercial antifungals and contributes to public health issues. The development of new antifungal therapies, particularly those targeting biofilms, is imperative. Thus, this study was conducted to investigate the antifungal and antibiofilm effects of Lactobacillus salivarius (L. salivarius), zinc nanoparticles (ZnNPs) and nanocomposites (ZnNCs) on C. albicans isolates from Nile tilapia, fish wash water and human fish sellers in Sharkia Governorate, Egypt. Methods: A cross-sectional study collected 300 samples from tilapia, fish wash water, and fish sellers (100 each). Probiotic L. salivarius was immobilized with ZnNPs to synthesize ZnNCs. The study assessed the antifungal and antibiofilm activities of ZnNPs, L. salivarius, and ZnNCs compared to amphotericin (AMB). Results: Candida spp. were detected in 38 samples, which included C. albicans (42.1%), C. glabrata (26.3%), C. krusei (21.1%), and C. parapsilosis (10.5%). A total of 62.5% of the isolates were resistant to at least one antifungal agent, with the highest resistance to nystatin (62.5%). However, 75% of the isolates were highly susceptible to AMB. All C. albicans isolates exhibited biofilm-forming capabilities, with 4 (25%) isolates showing strong biofilm formation. At least one virulence-associated gene (RAS1, HWP1, ALS3, or SAP4) was identified among the C. albicans isolates. Probiotics L. salivarius, ZnNPs, and ZnNCs displayed antibiofilm and antifungal effects against C. albicans, with ZnNCs showing significantly higher inhibitory activity. ZnNCs, with a minimum inhibitory concentration (MIC) of 10 µg/mL, completely reduced C. albicans biofilm gene expression. Additionally, scanning electron microscopy images of C. albicans biofilms treated with ZnNCs revealed asymmetric, wrinkled surfaces, cell deformations, and reduced cell numbers. Conclusion: This study identified virulent, resistant C. albicans isolates with strong biofilm-forming abilities in tilapia, water, and humans, that pose significant risks to public health and food safety.

Detection of Carbapenem-resistance in CRE by Comparative Assessment of RAPIDEC® CARBA NP and Xpert™Carba-R Assay.

Introduction: Carbapenem-resistant Enterobacteriaceae (CRE) infections resist nearly most available antimicrobials, resulting in poor clinical outcomes. Saudi Arabia has a relatively high CRE prevalence. This study aims to evaluate the sensitivity of Rapidec Carba NP test and GeneXpert Carba-R assay compared with conventional manners for detection of carbapenemase-producing Enterobacteriaceae. Methods: This is a cross-sectional study including a total of 90 CRE isolates examined at two tertiary hospitals in KSA from October 2020 to December 2021. Gram-negative Enterobacteriaceae were identified by using Vitek 2 system and were furtherly tested for imipenem and meropenem susceptibility by E- test strips, followed by Rapidec Carba NP test and the Xpert™Carba-R assay. Results: Carbapenem-resistant K. pneumoniae (78.9%) and carbapenem-resistant E. coli (14.4%) were the two most common isolates species. Colistin (98.9%) and tigecycline (88.9%) were the most effective antibiotics against CRE isolates, followed by amikacin (52.2%), gentamicin (33.3%), cotrimoxazole (15.6%), and ciprofloxacin (8.9%). blaOXA-48 was the predominant carbapenemase gene (44.4%), followed by blaNDM (32.2%). blaKPC gene was not detected. The Rapidec Carba NP and the Xpert™Carba-R demonstrated an overall sensitivity of 69.3% and 88%, respectively, in comparison to gold standard detection of meropenem and imipenem resistance by Vitek 2 system and E- test strips. Discussion: RAPIDEC® CARBA NP may be a beneficial screening test for detecting CRE, but for confirmation of the results, Xpert Carba-R assay is more sensitive, significantly lowering the turnaround time compared to reference traditional methods. The information on carbapenemase genes may be used for epidemiologic purposes and outbreak management.

Zamzam water is pathogen-free, uricosuric, hypolipidemic and exerts tissue-protective effects: relieving BBC concerns.

Zamzam water is the most frequently used drinking water by millions of people in Saudi Arabia. It is carried all the time by millions of pilgrims to their home countries as gifts to close and near relatives and friends. Safety of constituents of Zamzam water is a vital health topic. British Broadcasting Corporation (BBC) raised many health concerns regarding the high serum arsenic and nitrate contents in Zamzam water that may cause cancer. It is role of scientific research to present scientific facts to relieve such concerns. Arsenic is a carcinogen while nitrate causes methemogloinemia that affect oxygen carriage by haemoglobin. An ethical committee approval was obtained. Eighteen white albino mice (40-45 g) were used in this study. Three experimental groups were allocated (six mice per group): tap water group, distilled water group and Zamzam water group. Our data revealed that Zamzam water exerts tissue-protective effects that contradict malignancy. Our data proved that Zamzam water is pathogen-free causing no bacterial growth on CLED agar colonies. Zamzam water consumption for three consecutive months in mice was quite safe for the general health and significantly decreased serum uric acid (p < 0.05) (possibly due to Zamzam-induced urine alkalinisation facilitating uric acid excretion). Regular Zamzam water consumption significantly decreased serum cholesterol (p < 0.05) and serum triglycerides (p < 0.05). Hypolipidemic effects of Zamzam water may be due to its high mineral content facilitating increased lipids metabolism. Our data confirmed safety of prolonged use of Zamzam water comparable to other drinking water types regarding the metabolic and synthetic functions of the liver. Nitrates in Zamzam water are thought to be an original constituent that may be useful (exerting vasodilation, antithrombotic, and immunoregulatory effects) and not harmless. This may occur due to high Zamzam content of calcium, magnesium and selenium. Histologically, our data confirmed that Zamzam water was quite safe to renal parenchyma and comparable to other types of drinking water. In conclusion, health concerns raised by BBC regarding Zamzam water safety were a good chance for fruitful scientific research investigations that confirmed safety and beneficial effects of Zamzam water for human health.